Tears of the Tree
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Tears of the Tree THE STORY OF RUBBER — A MODERN MARVEL
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Tears of the Tree
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Tears of the Tree THE STORY OF RUBBER — A MODERN MARVEL
JOHN LOADMAN
AC
AC
Great Clarendon Street, Oxford OX2 6DP Oxford University Press is a department of the University of Oxford. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide in Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offices in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries Published in the United States by Oxford University Press Inc., New York # J. Loadman 2005 The moral rights of the author have been asserted Database right Oxford University Press (maker) First published 2005 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, or under terms agreed with the appropriate reprographics rights organization. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above You must not circulate this book in any other binding or cover and you must impose the same condition on any acquirer British Library Cataloguing in Publication Data Data available Library of Congress Cataloging in Publication Data Data available Typeset by Newgen Imaging Systems (P) Ltd., Chennai, India Printed in Great Britain on acid-free paper by Biddles Ltd., King’s Lynn ISBN 0–19–856840–1 (Hbk.)
978–0–19–856840–7
1 3 5 7 9 10 8 6 4 2
For Lina Marriage for over thirty-five years to someone with a passion for rubber must often have been difficult!
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Acknowledgements The basic framework of this book grew out of over thirty years of reading and collecting snippets from colleagues at the Tun Abdul Razak Research Centre (TARRC). The library there offered a range of early twentieth century books on rubber technology which were an invaluable source of primary data. Second-hand bookshops and internet searches for referenced books slowly filled in the gaps, as did the disposal of books and journals such as the India Rubber Journal and India Rubber World to the Plastics Historical Society (PHS) by universities which had no space in their libraries (or syllabuses) for old science books. More recently, information and illustrations have come to me from a wide range of sources. Many of the illustrations come from two locations, the photo-archives of the TARRC and the PHS. The latter set of some 700 glass lantern slides has an interesting history in that it was accumulated and catalogued in the 1920s by the Research Association of British Rubber Manufacturers, where it remained, virtually unknown and forgotten, until it was about to be thrown away in the 1990s. Luckily, the archivist of the PHS, Colin Williamson, saved them and they were donated to the PHS. Acknowledgement is given to both of these sources for the use of their collections and to Colin for scanning many of the slides onto a compact disk for me. Other illustrations have a range of histories. Those of the ball courts were supplied by my niece, Nesta Waters, whilst Ridley’s letter to Turrill, dated 8 July 1950, was initially located in the ‘Miscellaneous Correspondence Collection’ of the Royal Botanical Gardens, Kew by Hew Prendergast, and was supplied to me by Michele Losse and
Acknowledgements viii Julia Steele. The final paragraph is published with the permission of the Trustees of the Royal Botanical Gardens. The photograph of H. M. Stanley was unaccountably missing from the two large collections mentioned above and was supplied by the Royal Geographical Society, whilst the illustration of the principles of injection moulding was supplied by REP UK. Permission to reproduce them is acknowledged. Wong Fot Jaw kindly e-mailed me the photograph of the 1877 Hevea tree in Kuala Kangsar. The cartoon showing ‘imps’ attacking a piece of rubber in Fig. 13.4 was drawn by my old TARRC colleague, Peter Lewis, and is used with his permission. This truly is a case of one picture being better than one thousand words. The early history of the steamship Amazonas was found in the Maritime Navy List Maritime Directory by Bryan Smalley, who gave me its identification number—70893—from which later records could be traced. Details of the voyage to and from South America in the summer of 1876 including the crew agreement, records, and release documents were located at the Maritime History Archive of the Memorial University of Newfoundland by Paula Marshall, whilst the Amazonas’ ‘bill of entry’ was found in the Liverpool Records Office by another retired colleague and friend, Dr Arthur Edwards. Particular thanks are due to Frank James, a descendant of Thomas Hancock’s brother, John, and the family archivist who provided me with much biographical detail of the Hancock family. It was he who set me on the trail of the more than 700 lantern slides mentioned above. It was during this search that I contacted Jackie McCarthy at the Rubber and Plastics Research Association (Rapra) who, whilst searching unsuccessfully for the slides with Sheila Cheese, came across a dust-covered box containing numerous documents and correspondence relating to, or written by, Thomas Hancock which had been ‘loaned’ to the forerunner
Acknowledgements
ix of Rapra in the early years of the twentieth century and had lain ‘lost’ ever since. My thanks are extended to Carole Lee at Rapra for giving the documents to me to be returned to Frank James. My thanks are also due to Ted Rogers of the Hackney Borough Archives who was able to trace the location of Hancock’s home, Marlborough Cottage, from census and land registry records, although its well-established name was not found in any of the documentation. This enabled the PHS to place a plaque on a site of great significance to the whole of the industrialised world. I would also like to thank Ovidio Lagos, who is currently writing a biography of J. C. Arana, for supplying me with a portrait of the man himself. Finally, my thanks go to my friends at the TARRC, particularly Gail Reader for her help in many ways and David Cawthra for supplying me with the cover photograph of the Hevea tree being tapped. If any illustrations have ‘sneaked through’ without being accredited, I hope I will be forgiven and the original owner will be content to see his or her work published here.
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Contents List of Illustrations Outline Introduction
xii xvii xxv
1. The Mesoamericans and the ‘all-American ball game’ 2. Europe goes west 3. What’s in a name? 4. The battles of the giants—Charles Goodyear 5. The battles of the giants—Thomas Hancock 6. Rubber goes east 7. The King and the Congo 8. Slaves to rubber 9. Competition! 10. The heavy mob 11. Chemicals and curatives 12. Padding or performance enhancer? 13. The rot sets in 14. Death and destruction 15. Timeline
1 12 22 29 45 81 108 143 164 188 207 220 239 258 277
Bibliography Index
315 319
List of Illustrations 0.1 1.1 1.2 1.3 1.4 2.1 2.2 3.1a 3.1b 3.1c 3.1d 4.1a 4.1b 4.2 4.3 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11
Mayan doll made from fabric and rubber. Classical design of a ball court at Yagul. Mayan ball players. Ball court at Uxmal. Close-up of the ring. Severed head inside a Mayan ball. Charles Marie de la Condamine. La Gataudie`re. Hevea braziliensis Castilloa elastica Ficus elastica Landolphia owariensis Nathaniel Hayward His concrete ‘rubber tree’ memorial. Charles Goodyear. Charles Goodyear’s tombstone. Marlborough Cottage. Hancock’s pickle. Hancock’s first metal pickle. Charles Macintosh. The Hancock factory, Goswell Road, 1850. The ‘Grasshopper’, built by Easton & Amos, 1822. The Chas. Macintosh & Co. shop in Charing Cross, 1840. William Brockedon. The Chas. Macintosh & Co. trademark—HAN (d) COCK. Stephen Moulton. Rubber moulding of a pastoral scene which may have been shown on the Hancock stand at the Great Exhibition of 1851.
xxvi 3 4 5 7 14 20 27 27 27 27 39 39 42 44 47 51 52 54 55 57 61 63 67 68 71
5.12 5.13 5.14a 5.14b 5.15 6.1 6.2 6.3 6.4 6.5a 6.5b 6.6a 6.6b
6.7 6.8 7.1 7.2 8.1 8.2 8.3 8.4
List of Illustrations The Chas. Macintosh and Co. factory in Manchester as it was in 1857. Thomas Hancock: (a) an ebonite medallion, and (b) a portrait. Hancock’s memorial in Kensal Green Cemetery The inscription on Hancock’s memorial. Plaque erected on the site of Marlborough Cottage, 2003. A smoked ball of rubber (pelle) being cut in half in Para´ to check quality. Bill of Entry for the SS Amazonas, Liverpool, 12 June 1876: (a) heading, and (b) details. The last paragraph of Ridley’s letter of 1950. Henry Wickham with one of the original Heveas at Heneratgoda in 1911. One of the original Heveas planted at Kuala Kangsar in 1877 Its associated plaque. H. N. Ridley with a Hevea tree showing herringbone tapping. A modern tapping panel. Thin slivers are removed each time the tree is tapped. By tapping progressively the trunk can regenerate and the process can continue. Sir Henry Wickham, 12 october 1926. Tapping Hevea trees on a modern Malaysian plantation. How to get rich in the Congo. ‘Henry Morton Stanley’. Graph of rubber exports from Para´, 1836–1872. Sketch map of Brazil, Colombia, Peru, and Ecuador showing the rubber rivers and towns. Rubber dealing in Manaus in the early twentieth century. The public face of rubber tapping: (a) Amazonian Seringueiros, and (b) tappers smoking rubber pelles.
xiii 75 78 79 80 82 91 94 98 100 100 102
102 105 106 109 115 144 146 147 152
xiv 8.5 8.6 9.1
10.1 10.2 10.3 10.4 10.5 10.6 10.7a 10.7b 10.8a 10.8b 10.9 10.10 10.11a 10.11b 10.12 10.13 10.14 11.1 11.2 11.3
List of Illustrations The not-so-public face of the rubber industry: an Indian woman condemned to death by starvation on the upper Putumayo. J. C. Arana in 1925 as senator from Loreto. Graph of natural and synthetic rubber production 1900–1997, and natural rubber production as a percentage of the total elastomers produced worldwide. A simple spreading table. Hancock’s 1840 masticator. Single-roller masticators manufactured by (a) Francis Shaw, and (b) David Bridge. A three-roll calender. Moulton’s three-roll calender—the Iron Duke. Diagram of mastication and the addition of additives. An early electric two-roll mill A modern sixty-inch two-roll mill. A diagram of a Bridge–Banbury A Banbury internal mixer. Three-mould hydraulic press. Milling and extruding. A schematic illustration of injection moulding, supplied by REP UK A bathing cap being injection moulded. Batch dipping of (a) bathing caps, (b) catheters, and (c) balls and bladders. Modern continuous production of dipped medical gloves. Various toys made from latex. A rheometer printout for the vulcanisation of a ‘conventional’ mix. Sheets of natural rubber after smoking in a smokehouse. A vulcanised blend of natural rubber and nitrile rubber.
159 163
167 189 191 191 193 194 195 196 196 198 198 200 202 203 203 205 205 206 212 215 217
11.4a 11.4b
12.1 12.2 12.3
12.4
13.1 13.2 13.3a
13.3b
13.4 13.5
List of Illustrations xv A two-phase polymer system with weak bonding (white areas) between the phases 218 A three-phase polymer system where the third polymer (thin black line around the white areas) acts as a ‘compatibiliser’ between the other two phases. 218 An advertisement for rubber fillers which appeared in the early twentieth century. 221 A representative virgin carbon black as seen using a transmission electron microscope. 227 A micrograph of (a) a two-elastomer co-continuous blend, and (b) a two-elastomer blend showing one discrete (dark) phase and one continuous (light) phase. 230 Ebonite articles: (a) a jumble of necklace chains, (b) pendants, (c) buttons and brooches, (d) detail of one brooch (top right in (c)), (e) fountain pens, (f ) flute, (g) pipe bowl, (h) revolver hand grips, (i) brooch, ( j) Queen Victoria Jubilee medal, (k) ornamental comb, (l) combs, (m) medicine holders, and (n) cigarette lighter. 236–237 Examples of degraded rubber fabric. 240 ‘The Proofer’s Song’. 241 Substitution positions on a phenolic ring. This is the basic phenolic group. At each point (2–6) there is a C–H group and the substitution positions are named. 245 Possible atmospheric degradation routes illustrated by formulae. A commercial phenolic antioxidant (top) has alkyl groups at the ortho- positions which ‘block’ it from further attack. The left-hand product shows two molecules oxidised and joined together to give a quinone. The right-hand product has been nitrated in the para- position. 245 Pictorial illustration of possible routes to rubber degradation—the ‘imps’. 246 Sulphur bloom seen under a microscope. 252
List of Illustrations xvi 13.6 Stress-induced surface oxidation showing loss of the smooth surface. 14.1 ‘The Rubber Doll, A Christmas Story in Verse’. 14.2 Old tyres used as (a) boat fenders in Crete, and (b) planters in Malaysia. 14.3 A Mexican house using old tyres filled with soil to create a level stable (?) foundation. 14.4 ‘Tyred’ furniture. 14.5 A Malaysian rubber plantation (or factory?) in 1996.
255 259 267 268 269 275
Outline Introduction What is it all about? Can a natural product which has been in use for over three and a half thousand years still be relevant in today’s age of synthetics? This book sets out to look at the history of rubber, a unique material without which the modern world could not exist, and poses the question ‘If it was not there would we have invented it?’
1. The Mesoamericans and the ‘All-American Ball Game’ Although the story of rubber begins between thirty and sixty million years ago, genuine records of its use began with the earliest settlements in Mesoamerica. This chapter tells of the history of the ‘ball game’ from its earliest beginnings with the Olmecs around 1600 bc through to Cortez in the sixteenth century ad. It discusses the cultural significance of the game and its religious significance as set out in the Mayan ‘Council Book’, the Popol Vuh. This was the start of a long story of blood, sacrifice, and murder which was to last into the twentieth century!
2. Europe goes West This chapter covers the period from the early sixteenth century through to the development of Western interest in the material due to the exploration of Amazonia by Charles Marie de la Condamine and his relationship with the ‘Father of rubber’,
Outline xviii Franc¸ois Fresneau, towards the end of the eighteenth century. La Condamine used many words relating to rubber for the first time, including caoutchouc, generally translated as ‘the weeping tree’, but it is suggested that its origins could be from ‘caa ochu’—an ancient Inca word relating to mysticism and witchcraft—a connection quite possible in view of the horrors of the Popol Vuh. The chapter includes biographies of both men and describes their cooperative work, including the presentation of the first scientific paper on rubber, presented to the French Academy of Science in 1751.
3. What’s in a Name? Many plants produce latex and several plants of possible early significance are described here. There was much confusion over who was talking about what due to the range of botanical names given to many of these plants, and it took a sudden flash of realisation by a young student that different people were talking about different trees to make sense of the literature. The chapter also looks at the history of rubber-related names (including ‘rubber’ itself ) which are common today and discusses their origins.
4. The Battles of the Giants—Charles Goodyear Goodyear is well known as ‘the inventor of vulcanisation’ and this chapter, basically a biography of this perpetually ill man who sacrificed himself and his family in an attempt to cure rubber of its propensity to turn sticky when hot and brittle when cold, attempts to put some balance back into US presentations of the man as a genius and to look at what he was really like—his life of failures except for one fluke! It also contains a quote in full from a letter printed in a magazine in the mid-1860s which suggests that
Outline
xix it was a friend of Goodyear—a Mr Eli—who actually made the discovery (a letter believed to have been referenced nowhere before). Goodyear’s own description of his actual moment of discovery is so vague as to be historically useless and many different versions have been published since his original one. These are discussed.
5. The Battles of the Giants—Thomas Hancock Hancock was the founder of the UK rubber industry and this is his biography. It draws on family archives and many documents recently unearthed by the author ‘in a dusty box in a dusty cupboard under some dusty stairs’ which had been ‘lost’ since the early part of the nineteenth century. It looks at his siblings and their contribution to the world of rubber, as well as his complicated business relationship with Charles Macintosh. It describes the machinery he invented to process rubber and how this ran hand in hand with the industrial revolution—often at the ‘cutting edge’ of what could be made. Hancock’s independent discovery of vulcanisation, having seen from a sample of Goodyear’s material that it could actually be done, is described in some detail and should be recognised as possibly one of the first ‘design experiments’ in chemistry. For many years from 1836 onwards he was involved in numerous legal battles and these are detailed. The interesting fate of his home in Stoke Newington (which the author identified and documented for the first time) from his death until 1941 is briefly summarised. Many of the illustrations used in this and other chapters were discovered in a unique collection of lantern slides prepared in the early 1920s. The author discovered these slides in the archives of the Plastics Historical Society where they had been ‘forgotten’ after having being discarded by the company which had them ‘taking up space’.
xx
Outline
6. Rubber goes East The first part of this chapter describes the work of Clements Markham in organising the shipment of rubber seeds from Amazonia to the UK and their propagation at Kew. This includes Henry Wickham’s biography and the famous story of his ‘seed theft’, as it became known after he told the story, initially in 1908. Investigations by the author discovered new documentation on the ship which brought the seeds from Amazonia, including detailed crew records and the bill of entry of the cargo into the UK which indicated that much of Wickham’s story was untrue. The question of how much was true is discussed. The irony of the Brazilian Government in labelling Wickham as a thief when the original idea of plantation rubber came from a Brazilian (at that time there was no restriction on the export of the seeds), and another Brazilian had stolen coffee seeds from Cayenne to begin the Brazilian coffee industry, is mentioned. The second part of the chapter is concerned with the shipment of rubber seedlings to the Far East and the establishment of plantations in Malaysia. It was a time of chaos and confusion, and to this day some confusion exists as to whether the seedlings which formed the basis of the plantation industry were those brought to the UK by Wickham or by the plantsman, Robert Cross. Although many authorities have firm ideas on this, mostly favouring Wickham, the evidence is listed which shows that many quoted references are selective and there must remain some doubt. A paragraph of a letter written by Henry Ridley (the founder of the plantation industry in Malaysia) which claims that the seedlings were from ‘Cross’ plants and not from Wickham is illustrated. Wickham’s life after delivering the seeds to Kew is documented. As with Goodyear, he seemed to be beset by failure and the chapter ends with an assessment of his flawed character.
Outline
xxi
7. The King and the Congo This is the story of King Leopold II and his ‘rape’ of the Congo. It tells of his early days and his desire to have an empire (and money) for the new country of Belgium, and how he manipulated public opinion into allowing him to take over a country larger than Europe and to strip it of anything of value. He was not aware that rubber could be a significant crop until demand rocketed and it was found to be collectable from a vine growing throughout the country. He enlisted the aid of H. M. Stanley and his biography is contained in the chapter. Some details are given of the procedures Leopold and his agents used to obtain the rubber. However, nemesis was on the way in the name of Edmund Morel, a young clerk in the office of a shipping company used by Leopold. The chapter continues by describing his (initially) one-man attempts to expose Leopold and shows how he got support from Roger Casement and missionaries in the region to eventually persuade the British Parliament to take action to publicise the truth and force Leopold out of power. They never succeeded as he died fighting a series of rearguard battles and it took the Belgian Government a long time, even after Leopold’s death, to act. The chapter ends with some statistics on the weight of rubber obtained from the Congo, its value and its cost in lives—one native for every 10 kg of rubber!
8. Slaves to Rubber What happened in the Congo was also ongoing in Amazonia as various ‘rubber barons’ carved up the river valleys and worked them to death—along with the indigenous natives and those bought in to labour with them. This chapter tells of these barons and uses one particular expose´ by a young American engineer,
Outline xxii Walter Hardenburg, of Julio Arana to illustrate the cruelty in this region. The story is of particular significance in the UK as Arana established his company here to raise money and have ‘protection’ from the British establishment. It details Hardenburg’s adventures on the Amazon and the court case in Britain in which Arana and the British end of the company were brought to book. The ratio of rubber to native was rather more cost effective than in the Congo, with an estimated 150 kg rubber for every native life.
9. Competition! Inevitably, the Victorian scientists believed that they could do better than God (nature), so they set out to discover what rubber actually was and then to synthesise a synthetic material which would do the job just as well. Here we look at their attempts to understand the structure of natural rubber and then the development of the synthetic rubber industry. Particular reference is made to the lives of Waldo Semon and Wallace Carothers who, in the first half of the twentieth century, developed synthetic rubbers (and plastics) which are still elastomers of choice in many applications today and which set the basis of the synthetic rubber industry. The chapter concludes with a list of the majority of synthetic rubbers available today, in many cases what they are used for, and how they are designated.
10. The Heavy Mob This, and the following chapters, although ‘scientific’ and ‘chemical’, are written to be understood by non-technical or non-expert readers. The growth of the rubber industry through the nineteenth and twentieth centuries would not have been possible without the
Outline
xxiii development of machinery to mix rubber chemicals, mould the mixture, and vulcanise (cure) it to produce rubber products. This chapter describes this development from Hancock’s ‘pickle’ in 1819 to the modern equipment of today.
11. Chemicals and Curatives A vulcanised rubber product of today contains many ingredients, often a dozen or more, and a number of these are associated with the vulcanisation process. This chapter shows how a realisation that much more than just sulphur and rubber were involved in the process developed, and how different collections of chemicals (cure systems) were developed to give final products with optimised properties for their particular applications.
12. Padding or Performance Enhancer? Given the ever-increasing demand for rubber products through the second half of the nineteenth century, a demand which is still increasing today, and the shortage and expense of natural rubber, it was not surprising that it was soon found possible to add a whole raft of inorganic powders and still retain sufficient of the rubbery properties to make a commercially viable end product. This chapter investigates the history of the powders (fillers) used, the peculiar effects produced by some, and a realisation that some of them had much more to offer than just a ‘bulking-out’ effect.
13. The Rot Sets in Although Hancock claimed that the advent of vulcanisation had solved all the problems associated with rubber, he and many others soon found that the anticipated working life of many goods
Outline xxiv was cut short by degradation of the rubber so that, in the worst cases, they just fell apart. Here we consider the reasons for those problems and the development of chemicals which were able to slow down, but never halt, the inevitable deterioration. Some of these chemicals caused problems of their own and the reason for one—the bright yellow colouration of fabric in contact with rubber containing one type of chemical—shows that this is an ongoing area of research.
14. Death and Destruction As is implied in the previous chapter, all rubber goods have a finite life and the user or the producer is left with the problem of waste disposal. Recycling is the ‘buzz word’ of today and this final chapter discusses what ‘recycling’ options are available to a material which has been modified by vulcanisation so that, unlike glass or paper, the original rubber cannot be reclaimed. It has already been said that a rubber vulcanisate performs as it does because of its numerous additives, so we discuss what problems these might cause during any recycling process. Perhaps the final paragraph provides a new light with which to look at the argument between natural and synthetic elastomers.
15. Timeline A chronological listing of some 600 events in the history of rubber from the earliest days to 2000 ad.
Introduction There can be no one living today who is not familiar with rubber and its properties, but perhaps it is that very familiarity which has bred, if not contempt, at least an unthinking acceptance of the material and its position in society. This natural material has been used for almost four thousand years that we know of. It may, even today, be used ‘raw’ for creˆpe soles of high-quality shoes, or mixed with chemicals in the latex state, prior to having formers dipped into it, to produce such articles as baby bottle teats, condoms, or surgeons’ gloves. The mixed (or compounded) latex may also be treated to produce latex thread suitable for the finest underwear whilst, at the other extreme, dried rubber can be mixed with more chemicals, often including carbon black, to manufacture the strongest of engineering products, such as base isolation units for buildings in earthquake zones, conveyer belts, and, accounting for by far the greatest area of usage of elastomers, aircraft, off-road vehicle, and car tyres. If you doubt the remarkable properties of this material, then remember the faith a motorist puts in those few square inches of tyre which are all that hold a car (as well as its driver) on the wet tarmac as it powers down a precipitous mountain road. The history of the evolution of natural rubber, or NR as it is usually known, is a fascinating story. It is also a story confused in some important details, complex, and containing elements of greed and mayhem where, even today, the truth is sometimes obscure. For at least three thousand years before the first Europeans saw natural rubber, the Mesoamerican communities had developed
xxvi
Introduction
Fig. 0.1 Mayan doll made from fabric and rubber.
ways of collecting it and forming it into a wide variety of objects ranging from toys (see Fig. 0.1) and domestic products through medicinal devices and items relating to ritual sacrifice to tribute payments. They had also discovered ways of treating many of the objects to minimise their subsequent degradation during service. For some two hundred and fifty years following early European reports concerning this remarkable material, the ‘developed world’ was remarkably disinterested in its properties, and it was only in the mid-eighteenth century that the work of two Frenchmen, Charles Marie de la Condamine and Franc¸ois Fresneau, inspired the earliest stirrings of today’s rubber industry. Their reward was to be treated badly by history. La Condamine (1701– 1794) has several biographies on the Internet but only one, the
Introduction
xxvii ‘Catholic Encyclopedia’ (sic), notes ‘It is claimed that he introduced caoutchouc (natural rubber) into Europe.’ Of Fresneau (1703–1770), who has the strongest claim of all to be called ‘the father of the rubber industry’, even less is available unless one knows that his descendants are the Chasseloup-Laubat family and the family home is the Chateau de la Gataudie`re at Marennes. Two or three lines on that website provide his epitaph. There is also a picture on the site, but this contradicts the observation of his biographer (as we shall see in Chapter 2) that none exists. The embryonic industry grew slowly. It had a long history of failed applications, virtually all due to the different climatic conditions in Europe compared with those of Mesoamerica. Nevertheless, it was kept alive by a small number of dedicated scientists and entrepreneurs who believed that somehow rubber could be cured of its problems, which were mainly its tendency to become sticky when warm and brittle when cold. The door to solving this problem was opened in 1839 by the American Charles Goodyear, but he failed to patent his process until 1844. By this time the first patent for a similar process, based on the action between sulphur and rubber, had been granted to Thomas Hancock in the UK (BP9952/1843). This caused considerable resentment in the US, where it was claimed, an irrelevant point never denied by Hancock, that he only developed his procedure after examining a piece of Goodyear’s ‘cured’, or ‘vulcanised’, rubber. The embryonic industry passed rapidly to maturity without the usual childlike and teenage tantrums and, by 1868, the Frenchman, Turgan, was able to write: Rubber has, at the present day, become not only an essential factor of industry but also, and to an equal extent, of everyday life . . . it enters, under every size and shape, into the equipment of civilization.
Introduction xxviii It is perhaps ironic that these words were written some ten years before the invention of the internal combustion engine, twenty years before the pneumatic tyre, and thirty years before natural rubber latex medical gloves and condoms came into use. World commercial production figures for natural rubber in those early days vary from source to source, but during the 1850s it was probably no more than one to two thousand tons per annum. By 1875 it was close to 10 000 and at the turn of the century it passed 50 000, reaching 100 000 tons just before the Great War of 1914–1918. Today the world’s total production of rubber is about 15 000 000 tons, 6 000 000 tons of which is natural whilst 9 000 000 tons is synthetic. Obviously, the growth in demand for natural rubber closely paralleled the development of the motor car in the early years of the twentieth century (the reasons for the development of the synthetic rubber industry will be considered later), so the question is, where did all this rubber originate? The answer lies initially in the rubber-producing plants of the basins of the two great tropical rivers, the Amazon and the Congo, with lesser contributions from many other parts of the world. Later expansion was fuelled from plantations established in Ceylon (Sri Lanka) and The Federated States of Malaya (Malaysia), followed by India, Indonesia, and Thailand. The purpose of this book is to draw all these threads together and to examine the story of natural rubber in its social context. We shall begin by examining the ways in which it affected the lives of the Mesoamerican Indians, consider how tales of its uses and the material itself were brought to Europe, and then address the periods of native African and South American exploitation prior to the start of the Great War (1914–1918) which resulted in a native death toll considerably greater than that of the war itself.
Introduction
xxix We will look at the famous characters of the last 500 years who featured in the story, as well as the development of the rubber industry through the nineteenth century. This will include a chapter devoted to the way in which the seeds for the plantation industry (literally) were planted. We shall address the synthetic rubber industry, its genesis and development through the first half of the twentieth century, and the direction in which the whole rubber industry might be moving in the twenty-first century. In the last four chapters we shall consider the use of fillers to extend the bulk and improve the properties of vulcanisates, and take a brief look at our current understanding of the vulcanisation process—a process which was hardly comprehended, although used empirically, until the latter half of the twentieth century. We shall review the problems that arise during the life cycle of rubber articles and how chemicals to prevent their degradation were developed. Finally, we shall look past old age to the death of the product and how that great ‘buzz word’, recycling, could apply to rubber vulcanisates. The question is often raised, ‘If rubber had not existed would man have invented it?’ This raises another interesting question. If we had no concept of an elastic material would we think of trying to create one and, if so, when? The whole synthetic rubber industry developed from research in the late nineteenth century when chemists ‘broke down’ natural rubber, recombined it to an elastic material, and discovered polymerisation. It is also true that many of the important plastics of today were discovered by accident as chemists attempted to make rubbers. Even then, it took the demands of the Second World War and blank cheques from the US Government to produce viable substitutes for the natural material. One could reasonably argue that, even if a
Introduction xxx passionate desire had existed to invent a ‘bouncy’ or ‘stretchy’ substance, with no natural material to provide a starting-point it would have been unlikely to have been discovered before well into the second half of the twentieth century. That really would have changed the world!
1 The Mesoamericans and the ‘All-American Ball Game’ The oldest known sample of rubber was reputed to have been found in 1924, in Germany, fossilised in lignite deposits, and some sixty million years old. It is described by Schidrowitz and Dawson in History of the rubber industry (1952). This could be the same material described by Auleytner in 1953, which was again found in Germany and dated to the Eocene period, some thirty million years ago. The last-known location of this was the Jagiellonian University, Cracow in 1994, from whence it appears to have vanished. Apart from this, and one reference to very bouncy balls by Herodotus, who attributed their origins to the Lydians, the early history of rubber is solely a story of the ‘New World’, centred around the equatorial regions of South America and Mexico. The Mesoamerican civilisations of Central America are divided into three periods, although there is some disagreement about the exact dates involved. The Pre-classic or Formative Period is taken as being from around 2000 bc to ad 300, whilst the Classic Period, representing the golden age of the Maya, covered the years ad 300 to ad 900. The Post-classic Period covers the decline of the Maya from 900 to the early years of the sixteenth century and the arrival of the Spanish.
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Tears of the Tree
During these three periods there were numerous social units which developed, thrived for varying times, and then collapsed. The Mesoamerican era started with the ‘corn people’ or Mokaya who, as their name implies, are believed to be the first settled communities, as opposed to hunter–gatherer tribes. The Mokaya were followed by the Olmecs (c. 1500–300 bc), whose name means ‘rubber people’. The reasons for this are not fully understood, but may have been due to the significance to them of the famous Mesoamerican ball game which we know was played in formal ball courts from as early as 1600 bc and which represents the earliest certain use of natural rubber. Today the Olmecs are best known for their massive sculptures of individual heads, weighing up to forty tons each. These are now believed to be individual ‘portraits’ of their leaders which were disfigured on their deaths. The Olmec region was south of the Gulf of Mexico around La Venta in Tabasco and San Lorenzo, Tenochtitlan and Laguna de los Cerros in Veracruz. To talk of the Mesoamerican ball game is, perhaps, being a little simplistic since the game has a history extending over many centuries. It was played in Mexico (tlachtli), where it was seen and described by the conquistadors, by the Maya (pok-ta-pok), and by the islanders of the Greater Antilles (Batey). In all, the ball game is known to have extended as far south as Paraguay and north into what is now Arizona. Over a considerable timescale involving so many different and developing cultures it is inevitable that local variations would appear. The ‘game’ which the conquistadors saw and wrote of in the sixteenth century certainly seems to have differed in several ways from those played much earlier in the area’s cultural development. Our knowledge of the older versions of the game is obtained from classic art and archaeology. The ball courts were built in the shape of a capital ‘I’, with the length varying from that of a tennis
The Mesoamericans and the ‘All-American Ball Game’
3
Fig. 1.1 Classical design of a ball court at Yagul.
court to a football field or longer, see Fig. 1.1. The central flat strip was narrow when compared with the length and both sides were flanked by sloping banks which were used to keep the ball in play, rather like the sloping rooves of a real tennis court. At each end were markers, possibly indicating the ‘goal line’, and a later refinement was the incorporation of eyes or rings, one on each side, set in the top of the sloping banks, see Fig. 1.3. Most courts were aligned north–south and some locations had a number of different sized courts. The record seems to be held by El Tajin in Veracruz which had eleven courts, whilst one of the most famous Mayan ruined towns known today, Chichen Itza, had at least five. Here a great ‘wishing well’ has been excavated which was found to contain many sacrificial items (including human remains), rubber figurines, and torches with rubber cores which were burnt to generate thick black smoke, possibly to suggest rain clouds—homeopathic
Tears of the Tree 4 witchcraft! The earliest ‘written’ records which refer to natural rubber in the Americas are Aztec picture writings dating from the sixth century ad which show that rubber was used as a material for paying tributes and was also associated with devil-worship. Whilst most ball courts are in prominent positions near the cultural/religious centres of towns, some have been found at the boundaries between adjacent kingdoms, and it has been postulated that these could have been used for battles between rulers’ champions to settle ‘inter-kingdom’ rivalries and disputes. Teams varied in size from two to six and the general idea seemed, initially, to be to get the solid rubber ball, which varied in size from four to twelve inches in diameter, past the opponents’ ‘goal line’. The ball had to be kept in the air and all parts of the body could be used except the hands and feet. Each player wore protective clothing, knee and elbow pads, as well as a carved wooden or leather ‘yoke’ around his waist with which, by swivelling his hips, he could hit the ball with considerable force.
Fig. 1.2 Mayan ball players.
The Mesoamericans and the ‘All-American Ball Game’
5 Although all experts agree that hands and feet could not be used, two eighth-century Mayan sculptures show players holding the ball—half time? Points were scored for ‘goals’ and also if the opponents allowed the ball to touch the central flat playing area. With the advent of the rings, additional points were scored if the ball could be projected through the ring, see Fig. 1.3. By the time that the Spanish saw the game being played, they were treated to an ‘all fun and games’ version, with one writer describing how it was the custom for any player who succeeded in putting the ball through a ring to be awarded the clothes and jewellery of any spectator(s) whom he could catch.
Fig. 1.3 Ball court at Uxmal. Close-up of the ring.
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Cortez was so amused by the game that he took two teams (and some balls) back to Spain with him, where they were painted by the German artist, Weiditz. Although the Spanish were presented with a purely sporting activity, a study of Mayan carvings and pottery shows that the history of the ball game had considerable religious significance and was also bound up with ritual sacrifice. For instance, a relief in Izapa shows a decapitated (presumably defeated) ball-game player at the feet of the victor who holds his decapitated head, whilst a relief at El Tajin shows the classic Mayan scene of the loser having his heart cut out as an offering to the underworld to release the Sun for another cycle. There are many references to defeated warriors being forced to play against their captors prior to execution. We do not know if they were freed if they won, but in one illustration the losers were rolled up into balls and then rolled down an adjacent pyramid to their death. The use of the decapitated head, encased in rubber, as a ball is described in the Mayan ‘Council Book’—the Popol Vuh—and is illustrated in the fraction shown in Fig. 1.4 from a more descriptive illustration. The head is seen in profile within the ball. The religious significance of the ball game is most completely described in the Popol Vuh and the actual game, as played in the ball court, is a re-enactment of Mayan mythology, with the movement of the ball representing the cyclic journeys of the Sun and Moon through the sky, sinking to Earth only to rise again. The Mayan civilisation, which extended from around 1000 bc to ad 1500, had its origins in those Mokaya who moved further south and west, occupying the lowlands of the Yucatan Peninsular, with its most famous town of Chichen Itza, and the highlands of Southern Chiapas and Guatemala. The Maya created extensive cities built with carved and shaped stone, even though they were
The Mesoamericans and the ‘All-American Ball Game’
7
Fig. 1.4 Severed head inside a Mayan ball.
without metal tools or wheels to assist in the transportation of building materials. Their architecture is at least comparable with that of the ancient Egyptians. The cities contained many ball courts, some dating back to the earliest days of their emergence. In the highlands of Guatemala is the ancient town of Quiche´, the home of the Quiche´ Maya. The Popol Vuh is superficially their history, starting from before the dawn of life with the ‘divine matchmaker’, Xpiyacoc, and his wife, the ‘divine midwife’, Xmucane, who are the oldest of the gods. The saga continues from myth through history to conclude in the mid-1550s, at the time of its writing. It is, however, much more than just folklore and the Quiche´ Maya believed that within it lay the answers to all of life. It was consulted at the meetings of their council and this gave it its name—the ‘Council Book’. The ages of the stories are unknown but must date from the beginnings of the Mayan empire.
8
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The book was written anonymously in alphabetical Mayan, rather than in hieroglyphics, by high-ranking Maya who, ironically, had been taught the alphabet by missionaries so that they could read the scriptures! At the very beginning of the eighteenth century Francisco Xine´nez, a priest, saw the manuscript and copied it, dividing each page in two, down the centre, so that he could add a Spanish translation opposite the Mayan text. After many travels this manuscript eventually came to rest in Chicago in the year 1911. The significance of the book to the history of natural rubber is the prominence given within it to the ancient Mesoamerican ball game. Xpiyacoc and Xmucane had twin sons, One Hunahpu and Seven Hunahpu, and, bearing in mind that the characters are all gods, they jointly fathered with Blood Moon another set of twins, Hunahpu and Xbalanque. These five characters are the heroes and their adventures take place before the gods had managed to create humans. Both sets of twins play the ball game and the book follows an interwoven pattern of stories centred around the game and the battles they have with other gods. The individual episodes do not follow in chronological order, but are broadly divided into their adventures above ground and in the underworld. There are more complications in that, whilst the characters are generally treated as being on a terrestrial plane, the tales can also be interpreted at the celestial/astronomical/astrological levels, with various characters being (or becoming) stars. Places have both terrestrial and celestial significance. The episodes therefore tell of the creation of the Sun, the Moon, and the stars in human terms, whilst the tales provide an astrological ‘clock’ or calendar on which the Quiche´ Maya based their life. The battle of Hunahpu and Xbalanque with the gods ends in their death, which is interpreted as their victory since they are reborn
The Mesoamericans and the ‘All-American Ball Game’
9 as the Moon and Sun. The tests to which Blood Moon are put have celestial significance as they define the phases of the Moon. The Popol Vuh clearly shows that the ball game was a central part of the Mayan culture and provides firm documentary evidence of its religious significance. In referring to rubber as the ‘blood of sacrifice’ it provides evidence that at least some ball games were played as re-enactments of the sagas told in the book and that the vanquished players were sacrificed, whilst the word the Quiche´ use today for a graveyard is ‘jom’, the word used in the book for the ball court. Continuing the history of the Mesoamerican peoples, we find that to the north-west of the Olmecs was the cultural region of Teotihuacan, which began around 200 bc and which lasted for some 900 years. It was located in the central section of the Valley of Teotihuacan, which is on a 2000-metre plateau in the eastern part of the basin of Mexico. Teotihuacan was a trading state and data indicate that there were well-developed trading routes throughout Mesoamerica, with the Teotihuacans spreading their economic and ideological influence across the whole area. In ad 700 Teotihuacan was destroyed by tribes from the north, and this gave rise to a cultural wilderness which lasted until the rise of the Toltecs some 250 years later. The Toltecs were a warrior people who were important in that they maintained and extended the Teotihuacan culture. Their name is not a tribal name but simply means ‘craftsman’ in the Nahua language of Mexico, and it was used to distinguish those Mexican peoples who retained the culture and characteristics of the Teotihuacan peoples from others. By now the Mayan civilisation was in decline and the Toltecs expanded into large areas of their territory. The resulting culture is called ‘Toltec–Mayan’ and its greatest centre was at Chichen Itza on the Yucatan Peninsula. Around ad 1200, their dominance over the region faded.
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The last great period of cultural unification came under the Aztecs who, by the end of the Mesoamerican era in the fifteenth century, had built the most complex urban culture in Native American history. According to their own legends, the Aztecs (also known as the Mexica or Tenochca) came from north or north-west Mexico and were originally a group of tribal peoples living on the margins of ‘civilised’ Mesoamerica. In the thirteenth century they settled in the central basin of Mexico where they eventually found refuge on the small islands in Lake Texcoco. Here, in 1325, they founded the town of Tenochtitlan, some 60 km south-west of the site of Teotihuacan. They then set about creating an empire which, during the fifteenth century, was only surpassed in size (in the Americas) by that of the Incas in Peru. The Aztecs are the most extensively documented of all the Mesoamerican civilisations as Spanish soldiers, priests, and historians left numerous reports of all aspects of their life and culture. These showed them to have a highly sophisticated intellectual and religious outlook on life which placed their society as an integral part of the cosmos. The urban structure was based on individual specialisation, which included administrators, traders, and agronomists. The administrative structure was financed by tributes and it is recorded that their last king, Montezuma, received, inter alia, 16 000 balls of rubber each year as part of this. Although the ball game appears to have covered a vast area, the same is not true for the artefacts manufactured by the natives of the Amazon or Peruvian regions, which did not spread in the same way, possibly because they had much more practical and/or religious values. One example was the use of rubber for the manufacture of shoes. The Amazonian native was concerned with protecting his feet and did this by a straight over-dipping process, with his feet as the mould, to produce a perfectly fitting pair of galoshes. In the more civilised (questionably) courts of Mexico
The Mesoamericans and the ‘All-American Ball Game’
11 joke shoes were made in such a way that it was impossible to walk on them without tottering and falling over. They were used to shoe the dwarfs and hunchbacks who provided light relief for their lords and masters. Perhaps the most unusual recorded use was by the women of the Huitoto tribe of the upper Putumayo who coated their newborn children with latex to keep them warm immediately after their birth. On 21 April 1519 Montezuma was musing on Aztec folklore, which predicted that on that day the fearsome god Quetzalcoatl would return to claim his kingdom. He would arrive by ship from the east, would have a light skin, a black beard, and be robed in black. Later in the day, Fernando Cortez arrived at the court of Montezuma in Tenochtitlan and the Mesoamerican era was essentially over. However, by this time the natives over a vast region of equatorial America had developed processes for manufacturing articles from rubber which were at the forefront of technological innovation and which would take the ‘developed world’ a further 300 years or more to improve upon. The basis of many of these processes involved a controlled combination of drying and sterilising the latex products by smoking them over fires fuelled with certain nuts.
2 Europe goes West The prehistory of rubber took many years to deduce and resulted from archaeological excavations carried out right through to modern times and which are, indeed, ongoing today. The earliest ‘Western’ references to natural rubber inevitably involve Christopher Columbus, but the honour for the first certain reference to rubber in print belongs to Pietro, Martire d’Anghiera, who talked of ‘gummi optima’, and described how it was obtained from certain trees as a white juice which dried to a transparent material, the properties of which were improved by fumigation. For a few years the literature flowed. In 1535 Captain Gonzalo Fernandez de Oviedo gave a detailed description of the ball games played in the Greater Antilles, whilst Antonio de Herrera Tordesillas described how Cortez had watched such a game at the court of Montezuma. Probably the first and certainly one of the most prescient references to appear in popular print can be found in The alchemist, written by Ben Jonson in 1610. The character Sir Epicure Mammon, in describing the luxuries he would get when he had the secrets of the philosopher’s stone, said, ‘I will have all my beds blown up as down is too hard’; a remarkable flight of fancy because no suitable material existed at that time to contain the air. It was only in 1615 that Torquemada wrote of how his men discovered, or were shown by the South American natives, how to waterproof
Europe goes West
13 their capes by dipping them in the juice from certain trees—what we today call latex. We might not yet have a material for Sir Epicure Mammon but it is on the way. Torquemada also described the making of footwear, bottles, and a variety of hollow goods by the process of dipping over clay formers and then breaking out the latter. The medicinal properties of oil distilled from rubber were documented, including its efficacy in stopping haemorrhages when taken internally. His description of the relationship between rubber and devil-worship and other barbaric rites tied in closely with the Aztec picture writings mentioned earlier. He also included the first observations relating to the collection of the milky fluid. The (correct type of ) tree had its trunk incised with an axe and, from this, the fluid flowed. It was usually collected in special vessels but, if none was available, the natives would cover their skin with it and, when it had dried, peel it off in sheets. Perhaps this is why the natives had relatively hairless bodies! In 1653 Cobo wrote about coating long stockings with latex to protect his legs when walking in the tropical jungle, and the extension of this practice to hats and boots developed into an established industry in Mexico by the late eighteenth century. In the 1790s latex-coated fabric bags were manufactured to transport mercury. These replaced the chamois leather bags that had previously been used; a development much approved of by the chamois. However, for now, neither the reports nor the rubber products which came out of the Americas stimulated more than a passing interest in Spain or Portugal. The latter were simply regarded as curiosities, whilst there was no appreciation of the commercial landslide which was shortly to come. From 1615 to 1736 there appears a literary void, but from the latter date the start of the Western rubber industry can be set. This was due to the activities of two Frenchmen, Charles Marie de la Condamine (1701–1774) (see Fig. 2.1) and Franc¸ois
14
Tears of the Tree
Fig. 2.1 Charles Marie de la Condamine.
Fresneau (unfortunately, the biographer of Franc¸ois Fresneau, his great-grandson, The Compte de Chaseloup Loubat, states that there is no known portrait or other illustration of Frensneau). La Condamine was an exceptional gentleman of the eighteenth century. Born at the turn of the eighteenth century, he was a soldier, social climber, dilettante, and poet, but he was also a friend of Voltaire’s and had interests in chemistry, astronomy, and botany. He studied mathematics at the Jesuit
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15 College of Louis-le-Grand in Paris. On leaving the College, he joined the French army when war broke out. Although he was recognised for his bravery, he soon decided that army life did not suit him. In 1730 he joined the Acade´mie Royale des Sciences and sailed to Algiers followed by Alexandria, Palestine, Cyprus, and Constantinople, where he remained for five months. On his return to Paris, he published mathematical and physical observations of his voyage. In 1735 he joined an expedition to Peru to measure the length of a degree of meridian at the equator. The expedition was led by Louis Godin and the third scientist was Bouguer. The three arrived by different routes, la Condamine going overland from Manta, and the other two sailing to Quito where they joined up. Soon after his arrival in Quito, in 1736, la Condamine sent a package of rubber to the Acade´mie with a long memoir describing many aspects of its origins and production. These included the words ‘He´ve´’ as the name of the tree from which the milk or ‘latex’ flowed, and the name given to the material by the Maninas Indians, namely ‘cahuchu’ or ‘caoutchouc’. La Condamine’s word ‘caoutchouc’ is generally taken to be based on the Indian ‘caa ochu’—‘the tree that weeps’—but, in view of the early religious significance of rubber, it is interesting to note that in a dictionary of the Kechuan language of the ancient Incas, written by Holguin in 1608, he translated ‘cauchu’ as ‘he who casts the evil eye’, whilst other writers have also noted the connection between the word and things magical. It has also been related to a native word for blood, and this could complete the circle to the weeping (bleeding) tree romanticised by Vicki Baum. Regardless of which is correct (and both could be), these are the likely origins of the current German and French words ‘kautschuk’ and ‘caoutchouc’.
16
Tears of the Tree
La Condamine later described the smoking process by which the natives made the rubber stable and the wide range of goods which were produced, including the following: They [the natives on the banks of the Amazon] make bottles of it in the shape of a pear, to the neck of which they attach a fluted piece of wood. By pressing them, the liquid they contain is made to flow out through the flutes and, by this means, they become real syringes.
From this the Portuguese called the tree ‘pao de Xiringa’ (syringe wood) and the rubber tappers or harvesters ‘Seringueiros’. The tree which la Condamine called ‘He´ve´’ we now know as ‘Castilloa elastica’, but he did not realise that the one he described a decade later, the ‘pao de Xiringa’ or Seringa tree, was different. The use by the Portuguese of words derived from the native syringe was extensive. Not only are the labourers called ‘seringueiros’, but the village which is the centre of their daily toil is called a ‘seringal’. The emphasis on one particular instrument which the Indians manufactured is possibly due to the uses to which the syringes were put. La Condamine said that at any banquet or meal with the Omaguan natives it would be impolite not to offer each guest a syringe filled with hot water to be used before sitting at table. He does not go into details, but the sentence is part of a section on medical practices. Fordyce Jones swallows his scruples and mentions enema syringes as being produced by the Amazonian Indians, and at least one author has queried as to whether coming into contact with these practices might have been the origin of ‘The great American sense of humour’. ‘Latex’, the word used by la Condamine to describe the juice of the tree, was derived from the Spanish word for milk and remains in use to this day.
Europe goes West
17 Godin, Bouguer, and la Condamine were soon involved in arguments which resulted in them all making (different) independent measurements. The work was completed in 1743 and the three began their returns by different routes. La Condamine decided to travel east, following the Amazon to the coast. He did not find the female warriors he had heard tell of, the Amazons from which the river’s name comes. The Amazons were first described by Francisco de Orellana who had followed the same route two hundred years earlier, fleeing from Pizarro, when he was attacked by long-haired natives dressed in simple shifts whom he assumed (erroneously) to be female. However, la Condamine did write the first scientific account of the Amazon which was later published as the Journal du voyage fait par ordre du roi a l’e´quateur in 1751. In Guiana he met Franc¸ois Fresneau, who was an engineer by profession and a botanist by inclination. Fresneau became fascinated with la Condamine’s rubber and was the first person to realise that this was a potentially useful industrial material. Franc¸ois Fresneau (1703–1770) was an unlikely soulmate for la Condamine. He was born in the house which his mother had brought with her as her dowry when she married Franc¸ois’ father, also called Franc¸ois, in 1700. It, and the town of Cayenne in French Guiana, were to be his physical and spiritual homes for much of his life. In 1726 he moved to Paris to study mathematics and drawing under M. Duplessis, and after two years became a certified engineer. A very severe attack of smallpox interrupted his studies and left him permanently disfigured (perhaps the reason for the lack of paintings or sketches of him), but he recovered and went on to become a certified astronomer in 1730. Soon afterwards he went to stay at the house of the Marquise d’Ambres, whose husband was the Lieutenant Ge´ne´ral de la Haute-Guyenne, where he was to draw up plans to restore his family home, ‘La Gataudie`re’. The
Tears of the Tree 18 Marquise was to be his protector until her death some thirty years later. One of her first actions was to introduce him to the ‘Minister of the Marine’—Maurepas—who obtained for him in August 1732 the post of engineer at Cayenne in Guiana with a specified brief both to design and construct new fortifications for the town and to investigate the local flora in the hope of finding some new plants for the ‘Jardin du Roy’. He set off for the New World in late 1732, and by 1733 had written to the Minister describing the poor state of repair of the fortifications and given his ideas as to how they should be reconstructed. Three years of frustration followed as political in-fighting took place in France, but in 1736 the plans were approved by the King. He was still unable to begin work in Guiana so, in the winter of 1737/38 he returned to his home, ‘La Gataudie`re’, where he met Ce´cile Solain-Baron whom he married on 10 June 1738. The two of them returned to Guiana, again to be involved in political manoeuvrings, until on 9 November 1740 it was made clear to everyone by Maurepas that the plans had the King’s approval and must go ahead immediately. Money was made available and he was at last able to start work. He was now content in this area of his brief and felt able to pursue the second part of it, namely to examine the flora of Guiana. It was during this period that he and la Condamine met and carried out their first scientific research together. However, by now la Condamine was keen to return to France and pick up his social life after a ten year absence. He returned with many notes, 200 natural history specimens and works of art, and found time to write six books on his experiences. It is worth noting that la Condamine also found and reported on the cinchona tree, another ‘white man’s miracle tree’ which was later ‘transplanted’ to the east by Sir Clements Markham to provide a source of quinine.
Europe goes West
19 Meanwhile, Fresneau continued his work, and in a letter to Maurepas dated 19 February 1746 he made his first reference to the milk of a tree which the Portuguese used to make a variety of objects (including syringes). However, in France it was regarded as just a curiosity within a long report on the various flora which could be transplanted to the ‘Jardin du Roy’. In 1748 Fresneau returned to France in ill health to find his wife dead, worn out by seven pregnancies and life in Guiana. It was whilst recovering at Marennes that he wrote his first ‘memoire’ describing the physical properties of rubber and how he saw its potential for uses in the west. He particularly emphasised the benefits for France and Guiana in its promotion. The memoire went to the new Minister for the Colonies, Rouille´, in the summer of 1749. He was not interested, but it eventually fell into the hands of The Academy of Science in Paris and thence to la Condamine who, having known and worked briefly with Fresneau, gave it his support and presented it to the Academy on 21 February 1751. In the same year Fresneau married Anne-Marie Horric de Laugerie and the two of them, together with Fresneau’s only surviving child, Charles, settled in Marennes to rebuild ‘La Gataudie`re’. The re-build included a laboratory on the ground floor, where he could continue his research into rubber, and particularly his search for a solvent which would enable him to prepare solutions which could be used for dipping, coating, etc. in the same way that fresh latex was used in Amazonia. This research continued for a number of years and gradually some interest was shown by the Government. In 1762 Vaucanson asked M. Bertin, the Controller-General of Finances, to write to Fresneau asking him to set down the results of his labours, and this he duly produced in February 1763, a document of some note, being the first scientific research paper on natural rubber. With the documents was a letter explaining that he had prepared
Tears of the Tree 20 waterproof fabrics by dipping the materials in solutions of rubber with turpentine as a solvent. Having received a ‘thank you’ from Bertin and nothing more, Fresneau asked his old friend, la Condamine, if his research could be presented to the Academy of Science. La Condamine said there would be no problem, but suggested that it should be rewritten as a scientific paper rather than retaining its existing form as a report to the minister. This Fresneau did and it was submitted in March 1765. However, at some time in 1763, two scientist friends of M. Bertin, He´rrisant and Macquer, claimed independently to have discovered turpentine as the best solvent for rubber, and they went down in history for that discovery. Unfortunately, there is no documentation in the Academy’s records for the year 1763 of their submissions, so we are left to wonder whether they had a private briefing from Bertin or whether it was just a coincidence! Fresneau certainly believed the former, as an exchange of letters between himself and Macquer clearly shows. Perhaps Britain had
Fig. 2.2 La Gataudie`re.
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21 a hand in Macquer’s good fortune; in 1766 Macquer had published his famous Dictionnaire de chymie which, incidentally, contained no mention of rubber, and this was translated into English by a ‘lunatic’—or more correctly, James Kier, a knowledgeable chemist and member of the Lunar Society of Birmingham. The translated dictionary was extremely well received and brought Macquer to the attention of the British scientific community which subsequently published his work, again in English translation. Fresneau, on the other hand, received little appreciation outside his native country. That was how things stood when Franc¸ois Fresneau died on 25 June 1770. However, his work had raised natural rubber from a passing curiosity to a useful industrial raw material, and he should be given his long overdue recognition for realising and developing its potential. It is gratifying to note that at the end of the twentieth century his greatgrandson, the Compte de Chassloup Loubat, restored ‘La Gataudie`re’, including Fresneau’s laboratory, to its former glory and it is now open to the public. It can be found at Marennes, near La Rochelle in south-west France (see Fig. 2.2).
3 What’s in a Name? At this point it is appropriate to consider what plants provide us with latex (hence rubber), the varieties which exist, and their relative merits to the rubber collectors of two centuries ago. Natural rubber, India rubber, or caoutchouc are all names for the solid elastic material isolated, one way or another, from the ‘milk’ or latex of various plants. Whilst these plants tend to occur in the tropics, there are many which grow in the temperate zones and also produce this material, although not in any commercial sense. Perhaps the most common sources in the UK are the dandelion and the goldenrod—snap their stalks and the white fluid is latex, which will dry to give rubber. Latex is therefore the white milklike fluid which is obtained by wounding the plant. In the case of the most common commercial source today, the tree Hevea braziliensis, a sloping incision is cut in the outer bark from which the latex will ‘bleed’ and the wound is refreshed by removing slivers from the surface of the cut on subsequent tapping days. The word ‘rubber’ itself did not come into use until the 1770s when Joseph Priestly observed that Nairne’s of London (an artists’ materials shop) was selling a half-inch cube of material for erasing pencil marks for three shillings. He called it ‘India rubber’, having found from whence it came, but it was another hundred or more years before this was adopted by scientists who preferred the ‘classical’ caoutchouc. The 1868 edition of Chambers encyclopaedia
What’s in a Name?
23 enters the material under ‘caoutchouc’, whilst the Encyclopaedia Britannica of 1876 enters it under ‘rubber’, and in the same year a chapter in Bevan’s volumes on British manufacturing industries is headed ‘Guttapercha and India-rubber’. From then on the word ‘rubber’ is used in the UK. Popular usage of the word became commonplace much earlier. Charles Dickens, writing in the Pickwick papers in 1837, describes how the lines on Mr Pickwick’s brow melted away: ‘like the marks of a blacklead pencil beneath the softening influence of India rubber’, and that Mr Dowler, ‘bounced off the bed as abruptly as an India-rubber ball’. In the twentieth century the application of this one word (rubber) expanded in common usage to include an ever-growing range of synthetic elastomers, something we shall return to later. It is interesting to look at the origins of the word ‘caoutchouc’ a little closer, but first let us consider the names of the trees from which this material comes as this also provides an interesting story. Fernando Hernandez produced a great survey of the natural resources of Mexico in the 1570s (Rerum medicarum bovae Hispaniae thesaures) which was only published in 1649. Here he wrote extensively about the rubber-producing tree which is today identified as Castilla elastica. He wrote: When the bark is tapped a gum flows out which is called ‘holli’ by the Indians . . . the gum is so resilient that, properly prepared and shaped into round balls, these balls can be used for the same purpose as our Spanish inflated leather balls.
In 1723, Father A. J. de la Neuville wrote of the peculiar gum (rubber) which the Indians of French Guiana used to make various artefacts and ornaments. He made no comments about the origins of the gum and had probably therefore not seen its collection, but,
Tears of the Tree 24 from his description, it seems likely that it was obtained from a vine of the order of Apocynaceae—probably landolphia. The Castilla elastica was also the tree described by la Condamine, and from this came the rubber samples which he sent to France in the 1730s. However, a decade later he saw the ‘syringe tree’ and did not realise it was different. Almost certainly, he had not seen the original Castilla but had only heard reports of it. It was this ‘syringe tree’ which Franc¸ois Fresneau found in French Guiana and wrote about to la Condamine and the Paris Academy of Science. By a pure fluke he appears to have found the one and only Hevea braziliensis in that country, and it is not surprising that his drawings caused confusion some time later. He did not give it its current name but just referred to the ‘enema tree’, after the stories of the uses to which the syringes prepared from the ‘syringe tree’ were put. Pierre Barre`re can lay claim to having been the second Western person to have actually seen rubber being produced. In 1743 he belatedly published his survey of the natural resources of French Guiana, in which he described how natives made the same rubber articles as those described by la Neuville from the milk obtained from a vine which he identified as belonging to the order of Apocynaceae. Since he was in French Guiana between 1721 and 1724, this must have predated the observations of la Condamine. In 1775 J. C. F. Aublet published a book on the plants of French Guiana, and in it he recorded a ‘rubber tree’ which we now know could not have been the same as Fresneau’s. However, at that time, Aublet believed that his tree, la Condamine’s, and Fresneau’s were the same. He came up with the name ‘Hevea peruviana’, thus giving la Condamine credit for his early discoveries. With a second thought, he then reasoned that, since he had not seen la Condamine’s tree but only the ones in French Guiana, he had better play safe, so he renamed his tree ‘Hevea guyanensis’
What’s in a Name?
25 (its present name). This upset many people who objected to a ‘localised’ name being given to a tree found all over the north of South America. At the same time, Aublet was castigating Fresneau for the poor quality of his sketches which looked nothing like his (Aublet’s) tree. One of Aublet’s other claims to fame was that he was the first Westerner to eat rubber seeds and, whilst finding them quite oily, was not averse to them. In 1794 Vincente Cervantes presented a paper at the Royal Botanical Gardens on the various rubber-producing trees of Mesoamerica and suggested that the trees of the Brazilian and Mexico rubber industries were different. It seemed to get little in the way of publicity and it was left to the Dutchman, Arnoud Juliaans, to study all the literature and shout the obvious for the world to see—THERE WERE AT LEAST TWO DIFFERENT TREES! The name Castilla elastica has been used earlier but its origins should be given here. Juan Diego del Castillo was a botanist who joined Cervantes in Mexico. He died there in 1793 aged fortynine, and left a considerable sum of money towards the printing of their projected book Flora Mexicana. Cervantes chose the name Castilla elastica in honour of his friend. In 1807 Persoon called the ‘syringe’ or ‘enema’ tree ‘Siphonia elastica’, whilst in 1811 Willdenhow, Director of the Berlin Botanical Gardens, came up with the name ‘Hevea braziliensis’. The dispute was only resolved in 1865/66 by Mu¨ller, who suppressed ‘Siphonia’ in favour of Willdenhow’s name which illustrated the Aztec origins of rubber technology and the geographical location of the tree. It is now appreciated that Hevea braziliensis is almost completely located south of the river Amazon in northwest Brazil, north Bolivia, and east Peru, whilst other rubberproducing trees of the genus Hevea are located north of the river to a latitude of about 6 N.
26
Tears of the Tree
Having dealt with the trees, we can now consider the material which we get from them. There are four New World native words for rubber and these are written as ‘Cauchuc’ (or caoutchouc), ‘Hevea’, ‘Olli’, and ‘Kik’. It has been said that there is a relationship between ‘caoutchouc’ and devil-worship and sacrifice but, before considering this, let us deal with the three other words. ‘Kik’ is a word from the Mayan language of the Yucatan Peninsula and means ‘blood’. It has never been used in the west to refer to rubber. ‘Olli’ comes from the Nahuatl language of ancient Mexico and, because of the locations of the various rubber-bearing trees, always refers to the Castilloa elastica. This is obviously the root of the current Mexican word for rubber—Ule. ‘Hevea’ was la Condamine’s word taken from the Ecuadorian Indians for the rubber-bearing tree itself, and has never been used in modern times to mean rubber. The modern word for rubber in Peru and Ecuador is jebe. This brings us to ‘Cauchuc/caoutchouc’, which is important in that it is the basis for the current French, German, Spanish, Italian, and Russian words for the material—and is complicated as it seems to have origins in at least four different languages. The Maı¨nas Indians of Peru have the word meaning ‘juice of a tree’, whilst other authorities have identified the word with the Tupi Indians of the Brazilian Amazon and also the word ‘Caucciu´’ from the Caribbean. Each could, of course, be relevant depending on which explorer met which native! The interpretation publicised by Vicki Baums’s eponymous novel Weeping wood is that of W. H. Johnson, who claims that ‘caoutchouc’ is a corruption of ‘caaocho’, itself derived from ‘Caa’, meaning ‘wood’, and ‘o-cho’, meaning ‘to run’ or ‘weep’. Perhaps the final word should lie with the Kechuan language of the Peruvian Incas as this was the most developed of four
What’s in a Name?
27 Indian languages. Here the 1608 dictionary of Diego Gonzalez Holguin translates ‘cauchu’ as ‘he who casts an evil eye’, whilst in 1653 Bernabe´ Cobo noted that the Mexican ‘olli’ and the Peruvian ‘cauchuc’ refer to the same material obtained from Castilloa elastica. It should be remembered that applications of rubber to witchcraft, sorcery, and ritual sacrifice (as well as the ball game) predate its more utilitarian uses. (a)
(b)
(c)
(d)
Fig. 3.1 (a) Hevea braziliensis, (b) Castilloa elastica, (c) Ficus elastica, and (d) Landolphia owariensis.
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Tears of the Tree
Other rubber-producing trees of historical interest are listed below. For various reasons, none challenged the Hevea braziliensis (see Fig. 3.1(a)) which today produces virtually all of the natural rubber used worldwide.
Castilloa (elastica and ulei): The former is found in Central America and Mexico (see Fig. 3.1(b)), the latter in Peru and Brazil. Manihot glaziovii: From the Ceara region of Brazil. Ficus elastica: Found in Java and Malaysia (see Fig. 3.1(c)). Landolphia: Creepers found mainly in the Congo basin (see Fig. 3.1(d)). Funtumia elastica: Found in West Africa. The following are also of related note:
Parthenium argentatum: A shrub producing guayule, which is regularly re-examined as a possible source of ‘local’ natural rubber by the US. It is found naturally in the arid regions of Mexico and the rubber has to be solvent-extracted. Dyera costulata: Found in Malaysia and Sumatra—gives jelutong, used in chewing gum. Genus dichopsis: Produces gutta-percha. Mimusops globosa: Yields balata. First harvested commercially in Guiana in 1863 and used for golf balls, insulation, etc. Today the Macushi Indians of Guiana carve animals from it which are sold to sustain their rural communities and lifestyle.
4 The Battles of the Giants—Charles Goodyear The first of our giants is Charles Goodyear who was born at Oyster Point, close to New Haven, Connecticut, in December 1800. Five years later the family moved to Union City, which would eventually become Naugatuck, and here his father, Amasa, opened a mill which manufactured a range of agricultural implements. Charles had two brothers and a sister Harriet. When he was sixteen an event occurred which was to be significant throughout much of his life; his father hired a tutor, William DeForest, who later successfully moved into wool (then rubber) manufacturing and also married Harriet. He was to be Goodyear’s ‘angel’ and supporter for the rest of Goodyear’s life. Goodyear initially entered the hardware business with his father but, after marrying Clarissa Beecher, moved to Philadelphia to set up his own hardware business. It was now 1826. By 1830 he had prospered and had three daughters, but it was a false dawn. His naive business sense, coupled with a downturn in the economy, left him hopelessly in debt and he enjoyed the first of many visits to a debtors’ prison. In 1831 he was declared bankrupt, lost the store, his rights in his father’s business, and a daughter born that year died shortly after. In 1833 his first son, Charles Junior,
Tears of the Tree 30 was born, but soon after his third-born daughter (Sarah) died, a pattern of good followed by bad news which was to follow him throughout his life. During this time he had tried to make ends meet by various inventions, but here his second fatal character flaw showed itself—he could have an idea but was unable to progress it to an end product. It should, perhaps, also be noted that he had a third flaw, although this was physical rather than temperamental. He had been a sickly child whose health never improved throughout his life. In the summer of 1834 he walked past the New York retail store of the Roxbury India Rubber Company, America’s first rubber-manufacturing company, and noticed a rubber life preserver or life jacket on display. It was not the rubber which attracted him but the valve used to inflate it. He thought he could invent a better one, so he took a life preserver home with him, developed an improved valve, and returned to the store to show the manager the valve he had devised. The manager was not interested. The company was not in the market for valves now and it would be lucky to stay in business at all. He showed Goodyear racks of rubber goods which had melted to a stinking gum in the heat. Goodyear disappointedly pocketed the valve and took his first good look at rubber. He experienced a sudden curiosity and wonder about this mysterious material. ‘There is probably no other inert substance’, he said later, ‘which so excites the mind.’ Returning to Philadelphia, Goodyear was clapped into jail for debt. Whilst there he asked his wife to bring him a batch of raw rubber and her rolling pin. In his cell Goodyear worked his first rubber experiments. If rubber was naturally adhesive, he reasoned, why couldn’t a dry powder be mixed with it to absorb its stickiness—perhaps talc or magnesia? Once out of jail, he, his wife, and small daughters made up several hundred pairs of
The Battles of the Giants—Charles Goodyear
31 magnesia-filled rubber overshoes in their kitchen; but, before he could market them, summer came and he watched them sag into shapeless lumps. Life got no better for Goodyear and his family. Borrowed money ran out and they moved to successively poorer rented properties until in 1836 he moved his experiments to New York, where a friend gave him a spare bedroom for his ‘laboratory’. Just before the move a sixth child, William, had been born, but he only lived a few months. Goodyear still persevered with what can only be described as his obsession. He was now adding two drying agents to his rubber, magnesia and quicklime, and improving the product all the time. He had turned to decorating and painting his shoes to hide the sticky surface, and one day he decided to repaint an old decorated sample, so he applied nitric acid to remove its bronze paint. The piece turned black and Goodyear discarded it. A few days later he found it again and realised that the nitric acid had done something to the rubber, making it smooth and no longer sticky. He managed to convince the Roxbury India Rubber Company (which had just managed to stay in business) that he was on to something, and the company gave him access to its factory and raw materials so that he could continue his experiments. Here again his inability to see projects through to completion led to friction and he was eventually told to leave. Soon after came a pivotal event in his life. He met Nathaniel Hayward, who had worked for the Eagle Rubber Company in Easton, Pennsylvania throughout the 1830s. The firm had not been successful and in 1838 Hayward took it over, moving to Woburn, Massachusetts. At that time the reputation of rubber was at rock bottom and Hayward was unable to make a success of his company, so he agreed to turn over the factory to Goodyear in exchange for an agreed contract as foreman. He also agreed to
Tears of the Tree 32 hand over all of his research information. One item was his discovery that dusting rubber sheets with sulphur, or painting the surfaces of the sheets with solutions of sulphur in turpentine and exposing them to sunlight (a process he called ‘solarisation’) ‘causes the gum to dry more perfectly and to improve the whole substance thereof rendering it much superior to that prepared by any other combination therewith.’ This process he patented, at Goodyear’s suggestion, late in 1838 (US Patent 1090 granted 1839), and immediately sold it to Goodyear. Goodyear, rubber, and sulphur had now come together, but he already had in hand a government contract for 150 mailbags which were to be manufactured by the process which involved treating the rubber with nitric acid. After making the bags at Hayward’s old factory in East Woburn, Massachusetts, he relaxed and took his family on vacation. When he returned, the mailbags had melted to a sticky gum! This was another disaster and one which not only forced him back to poverty and made him give up the Eagle mill, but also disillusioned many of his friends and supporters. It could well have been the final debacle which prevented what was to come being his lifeline to fame and fortune. It was now 1839 and Goodyear continued to use sulphur in his experiments as a ‘drying agent’. He made numerous visits to the factory at Woburn for the purpose of closing it down and disposing of its assets and, quoting his own words (Goodyear wrote all of his autobiography in the third party): While on one of the visits above alluded to, at the factory at Woburn, and at the dwelling place where he stopped whenever he visited the manufactory at Woburn, the inventor made some experiments to ascertain the effect of heat upon the same compound that had decomposed in the mail bags and other articles. He was surprised to find that a specimen being carelessly brought
The Battles of the Giants—Charles Goodyear
33
in contact with a hot stove charred like leather . . . He however directly inferred that if the process of charring could be stopped at the right point, it might divest the gum of its adhesiveness throughout which would make it better than the native gum . . . India rubber could not be melted in boiling sulphur at any heat ever so great but always charred.
He had made what today we call vulcanised rubber. But now he was very ill and had only taken the first step along the long road of his great invention. He knew that heat and sulphur miraculously changed rubber, but how much heat was needed and for how long? He experimented with hot sand, flat irons, boiling water, and everything he could think of until, at last, he decided that steam under pressure, applied for four to six hours at around 130 C, gave him the best results. Whilst the above quotation from Goodyear’s autobiography actually gives us minimal information about his discovery, other, different, stories abound, although a similar story is told in The Readers Digest of 1958, and shown on the Goodyear Corporation website. (Incidentally, the Goodyear Corporation has nothing to do with Charles Goodyear but used his name when it was founded thirty-eight years after his death.) Others claim that the discovery took place in the laboratory at his house, and certainly the classic picture is more suggestive of a home laboratory than a shop. One ‘domestic’ story tells how, one day, while holding aloft a ladle of his latest failure, Goodyear gave the mixture an angry shake. A glob flew from the ladle and landed on a hot stove. He peeled the rubber concoction off the stove and was amazed at what he had. The heat had changed it. Kneading the small piece in his fingers he found that it was now strong and elastic. Another reads that Goodyear had invited some friends over to show them his ball of gummy rubber. He had managed to harden it by mixing the rubber with sulphur and treating it with an acid gas. As people
Tears of the Tree 34 began to toss the rubber ball around, it accidentally landed on a hot wood stove. The rubber began to melt and Goodyear was terribly upset. However, as he attempted to scrape the rubber off the stove, he discovered it had hardened to the consistency he had been trying to achieve. Yet another ‘domestic’ story involves rubberised fabric, which has some primitive basis in truth as Goodyear himself talks of a subsequent experiment in which he heated some of the treated mailbag fabric—although he claimed to use an open fire—in one attempt to make a better rubber. Goodyear mixed rubber with sulphur and white lead, and painted the mix onto a piece of fabric. Then somebody, no one knows just who, left this piece of rubberised fabric on a hot stove top. Goodyear realised from the smell that the fabric was burning, but before he could throw out the charred remains, he noticed that the material had charred but the rubber had not melted under all that heat, as he would have expected. The problem with the various ‘stove and compounded rubber’ stories which are attached to Charles Goodyear is that he does not seem to be the only claimant for it!. The following letter was written by Morriss Mattson MD to an American friend. It is undated but can be found in The India rubber and gutta-percha and electrical trades journal of 1887. I have been familiar with everything relating to rubber since its first inception as an industrial interest and yet I am free to confess that I do not know what are the current statements as to the true origin of its vulcanisation. It is universally conceded that Mr Goodyear was the discoverer and I have no disposition to pluck a single laurel from his brow, Yet history is uncompromising in her demand, always requiring the exact truth in reference to every great discovery . . . Be it known that the first great movement made in reference to its manufacture was by a Mr Hayward of Boston who discovered that sulphur was a
The Battles of the Giants—Charles Goodyear peculiar drier of rubber, if I may so express myself, and that by mixing the two together the resulting compound could be forced into thin and delicate sheets and fabricated into various useful and beautiful articles. Very soon a store was opened in Boston for the sale of these articles, and I remember that they elicited a great deal of public admiration. Indeed they were ornamented in a very high degree. A Mr Eli was the proprietor of said store and many were the conversations we had in reference to the probable future of this new movement in rubber . . . Mr Goodyear was in the habit of passing in and out of this store, according to my dim recollections, but whether he had an interest in the business I cannot say. He was not then the observer of all observers but simply a very plain, unpretending, citizen, known as the patentee of a few but, perhaps, not very profitable inventions. Mr Eli’s store was heated by an anthracite stove which had a flattened top, and that memorable stove I can see in ‘my mind’s eye’ as though I had visited that little store in Walther Street but yesterday. Nothing was dreamed of in that store but the sulpho-rubber compound, and, of course, they were to be seen scattered in every direction, just as bread and dough are seen in a baker’s kitchen. A small mass of the aforesaid rubber compound had forced its way, by some accident, upon the top of the aforesaid stove. Perhaps it had been used to protect the fingers against the heat in moving the lid of the stove. But this is only a surmise. How long the rubber mass had remained upon the top of the stove I have not the tongue of tradition to give an answer. Let this pass then, as an inscrutable mystery, unless someone can throw more light on the subject than myself. In the meantime Mr Eli was standing beside the stove seeking the genial warmth radiating from the glowing anthracite within. He espied the mass of rubber of which I have spoken and carelessly took it up for examination. To his surprise he found that it was entirely different from the ordinary sulpho-rubber with which he was so familiar. It was entirely changed in texture. It was tough, hard, strong yet elastic. What had produced this change? Surely the heat of the stove. Here was a grand secret, a grand revelation, a grand
35
36
Tears of the Tree discovery; but a discovery by accident, and many of our greatest discoveries come to us by accident. Mr Eli, as I well remember, had a sharp and intuitive mind, and probably was not slow in perceiving that the anthracite stove had flashed forth to the world an unexpected revelation of inconceivable value to the human family. He must have thought about it, dreamed about it, and talked about it and yet I do not remember of his saying anything to me upon the subject beyond the mere recital which I have just given to the reader.
What one makes of these stories, and in particular the last one, is something for the reader to decide. Goodyear certainly knew William Ely of New York as someone who had backed him financially in the late 1830s, but there is no mention of him in this context in his autobiography. It is an inescapable fact that, if only Goodyear had expanded a little on the details of his great discovery, then there would have been much less speculation as to what really happened on that day in 1839. Now let us return to Goodyear’s story. Due to his earlier cries of ‘Wolf ’ he was unable to convince anyone that he had actually achieved something worthwhile and, indeed, in practical commercial terms he had not. All his efforts to produce a consistently vulcanised sheet of rubber ended in failure. In 1842 Goodyear showed Horace Cutler, a shoemaker who had a factory near where Goodyear was working, some of his vulcanised rubber and, when Cutler expressed interest (and offered financial backing) to manufacture rubber overshoes, Goodyear had to point out that he was not actually at a reliable production stage yet—and then went on to prove it. Cutler and Goodyear had split up by late 1842 but, from the ruins of their production, Cutler managed to find a few decent pairs of overshoes which he sold to another rubber manufacturer—Horace Day—in order to get some return on his failed investment.
The Battles of the Giants—Charles Goodyear
37 As far as Goodyear was concerned this was a disaster waiting to happen as Day, a hard-nosed businessman, was determined to find out what Goodyear had done to his rubber and to copy him. Unlike Goodyear, who had no interest in money, and certainly no ability to make any, this was Day’s driving ambition, and the two would fight their way through the US courts for many years to come. Day’s first action was to persuade the disillusioned Cutler to come and work for him, on the understanding that he would reveal all that he knew of Goodyear’s process. Cutler soon realised that Day was not a man he wished to work for and left; but, before going, he did agree (for a price) to pass on every bit of information he had about the Goodyear process. Day set out to emulate Goodyear but, like the latter, he was unable to make any products which were of a consistent quality. By now it was mid1843 and we have clear evidence that, whilst Goodyear’s vulcanisation process may on occasion have produced saleable articles, it was hardly a patentable process! Goodyear was probably aware of this and it could well have been one of his reasons for failing to take that route. Like Thomas Hancock, whom we shall come to later with his masticator or ‘pickle’, secrecy during development could have been the best option—if only he could have got the process to work quickly and reliably. By now Goodyear found himself penurious again and back in jail. On his release he realised that he had exhausted his possible partners in America, so he decided to turn to Great Britain which, he knew, had a considerable (unvulcanised) rubber industry but no knowledge of his process of vulcanisation. He employed an Englishman who was living in the US at that time, Mr Stephen Moulton, to act as his agent and to negotiate a deal to sell his secrets there. If he had felt able, on a technical basis, and had had the funds to patent his process before trying to enter the
Tears of the Tree 38 UK market, the story might have been very different. However, he did not, British industry was not impressed, and the UK glory went to Thomas Hancock as we shall see later; but, before following that story up, we shall continue with Goodyear’s. Having learnt a lesson for his UK experiences, Goodyear at last patented his process in the US in early 1844. Ironically, one of the first people to take out a licence to manufacture rubber goods under Goodyear’s vulcanisation patent was the man who had introduced him to rubber and sulphur, Nathaniel Hayward, but he soon transferred this to Gandee and Steele of New Haven, whose company went on to become part of the United States Rubber Company in 1892. In 1844 Hayward and Burr established the Hayward Rubber Company at Lisbon, Connecticut. From here, rubber products, boots, and shoes were shipped all over the country and, although Hayward retired in 1864 because of ill health, the company thrived until 1893 when it was closed. Later the building burned to the ground. Hayward died in 1865 and is buried in the small rural town of Colchester, about sixty miles north-east of New York. This town, today with a population of around 10 000, has a unique place in the history of rubber since in its churchyard is a tombstone and memorial to Nathaniel Hayward, the latter in the shape of a 10 ft high concrete rubber tree trunk, whilst the former identifies him as the inventor of hard rubber (ebonite or vulcanite)—an arguably contentious statement which we shall consider later (see Fig. 4.1). Returning to Goodyear, it was time for his brother-in-law, William DeForest, to come to his rescue again by setting up the Naugatuck Rubber Company (which would go on to become Uniroyal). For a cash sum the company bought the rights to all of Goodyear’s patents, past and future, although he retained the
The Battles of the Giants—Charles Goodyear (a)
39
(b)
Fig. 4.1 (a) Nathaniel Hayward, and (b) his concrete ‘rubber tree’ memorial.
right to sell elsewhere licences to any patent which the company declined to use. The company immediately began to make money and Goodyear was allowed space in the factory to experiment. This, however, soon turned into a disaster as his investigations and demands interfered with the smooth running of the production unit, and he was shown the door. It was time for Horace Day to surface again, and he now dropped any subtlety by applying for a patent which was essentially based on that of Goodyear. It was rejected outright, but Day would not go away and he began to manufacture shirred cloth, although Goodyear had already assigned that licence exclusively to a third party. It was now time for Goodyear to take action against Day in the courts, but they never got there. The two settled and Day received the shirred cloth licence which the third party had sold back to Goodyear. Although this would have made Day a rich man, it was not enough and he began manufacturing a wide range of rubber goods. This was a serious mistake. He was
Tears of the Tree 40 now not just infringing Goodyear’s patent, but manufacturing and marketing goods which were covered by licences issued to a number of rubber companies who did not wish to see their prosperity threatened and had both the money and will to fight. It was now 1851 and Goodyear was in the UK for Queen Victoria’s Great Exhibition. He had borrowed extensively from his brother-in-law to create a propaganda masterpiece, and this he succeeded in doing with the creation of his ebonite rooms—the ‘Goodyear Vulcanite Court’. Ebonite was, after all, a reliable material in his hands. He just kept on heating his mixes until they were rock-hard. However, contrasting with Hancock’s stand, there was relatively little ‘soft’ vulcanised rubber on display. Hancock’s display, on the other hand, concentrated on a vast range of practical vulcanised articles, clearly illustrating the difference in character between the two men; Hancock the industrialist and Goodyear the showman. Both men must have studied each other’s displays with interest, but there is no record of their meeting nor of what they thought of the other’s achievements. Hancock probably admired the quality of Goodyear’s ebonite mouldings but wondered about their commercial practicality, whilst Goodyear no doubt still failed to understand that a creative artist must also make money to live— unless he has enough friends to borrow from—but he was soon back in the States for the battle against Horace Day. This was going to be one of the greatest trials in American history, with Daniel Webster appearing for the rubber companies and Rufus Choate for Day. Both were brilliant orators, with Choate, the younger upstart, fighting Webster, the old lion. The truth would not really matter in this trial of oration; indeed, it featured but rarely. Choate’s defence was that numerous people, all produced in court, had carried out Goodyear’s experiments before he had—one of those being Day himself who claimed to
The Battles of the Giants—Charles Goodyear
41 have carried out Goodyear’s exact work as a fourteen-year-old in 1827! These matters were quickly put aside and the manufacturers’ unanswerable question was: if Day knew Goodyear’s patent to be invalid, why did he give it credence by taking out a licence to manufacture shirred cloth in the first place? When summing up, Webster spoke for two days, weaving Goodyear’s sad story of deprivation and suffering into the battle for the American constitution, the authority of Congress, and the rights of man. The verdict was a foregone conclusion. Goodyear’s patent rights were cast in stone and Day was hit hard in both reputation and pocket as the court ordered his factory records to be checked and all monies due to the injured parties to be calculated and paid. Although too long to reproduce here, the full text of Webster’s oration was published in the New York Daily Tribune at the end of 1851. Unfortunately, no record of Choate’s summing up has ever been found. Goodyear’s rubber had now taken off with a vengeance in America and he found himself with time for two new projects. The first (in 1853) was the publication of the first part of his history of rubber: Gum elastic & its varieties with a detailed account of its applications and uses and of the discovery of vulcanization (a catchy title), of which only a very few copies were ever printed, one having rubber pages. The second volume: The applications and uses of vulcanized gum elastic followed later in the same year. A few further copies appear to have been printed in 1855, but, again, these exist only in very specialised collections and the commonly available version today is a facsimile reproduction published in London by The India-rubber journal in 1937. The original appears to have been rushed to print whilst Goodyear was in France preparing for the Paris Exhibition of 1854/55 and contains a number of blanks or dashes to be filled in later. Again, Goodyear’s mercurial flitting from project ‘A’ to ‘B’ had got the better of him!
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It was in London in 1853, whilst preparing for the Paris Exhibition, that disaster again struck. Goodyear’s ever-supportive wife, Clarissa, took ill and died aged just forty-eight. He poured himself into his preparations, determined to make his display at this exhibition even greater than it was in 1851, and just over a year later he arrived in Paris having found a new wife, a twentyyear-old Englishwoman, Fanny Wardell. It was during this time that Goodyear persuaded George Healy to paint on a sheet of ebonite that which is probably the most recognised painting of him—romanticised and worry-free—a long way from the true picture of the sick man, aged beyond his years, who staggered into Healy’s studio (see Fig. 4.2). Once again, his exhibits were often of ebonite, many carried over from the 1851 Great Exhibition, but with a number of new ones made by French manufacturers to his specification. More
Fig. 4.2 Charles Goodyear.
The Battles of the Giants—Charles Goodyear
43 adulation followed and so did the bills. Before the exhibition was over he was experiencing a French debtors’ prison, where he was pleased to receive the ‘Grand Medal of Honour’ and the ‘Cross of the Legion of Honour’, awarded by the Emperor Napole´on III for his contribution to the exhibition. Freed from the French prison, he returned to England where, after another spell in an English debtors’ prison, he was released in time for his court battle with Thomas Hancock. The court found in Hancock’s favour (we shall return to this in more detail later) but Goodyear remained in London, and later Bath, carrying out research using compounded rubber supplied by Stephen Moulton, originally his agent who had brought samples of his vulcanised rubber to England in 1843 and who now had a thriving rubber business at Bradford-on-Avon, near Bath. It was here that family misfortune continued to take its toll with the death of Fanny’s first-born son, but this was compensated for by the birth of a second son, Arthur. As ever, Goodyear was unable to pay Moulton for the rubber with which he was supplied, and by mid-1858 it was obvious that he had exhausted Moulton’s goodwill. He returned to the States, albeit claiming that his return was demanded by his licensees as his patent was soon to expire and they wished him to seek an extension. Needless to say, Horace Day would be there to object, whilst Hancock was also there to oppose Goodyear since expansion into the American market now held many attractions for him and the company he was now associated with—Chas. Macintosh and Co. This time it was Goodyear’s turn to win against Hancock, or, more accurately, for Goodyear to continue his string of victories against Horace Day, and he was awarded a seven-year extension. It has already been said that almost every piece of good news which Goodyear received had to be paid for, and this time it was
44
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Fig. 4.3 Charles Goodyear’s tombstone.
with the death of Arthur. A year later Fanny gave birth to a girl, but at virtually the same time Goodyear received news that his second daughter by Clarissa, Cynthia, was seriously ill in New Haven. Goodyear was in Washington and ill himself, but he set out by sea to avoid the rough cross-country journey. When the ship docked in New York he found that he was too late. Cynthia was dead. Charles Goodyear collapsed in grief and died in New York on 1 July 1860 with Fanny at his bedside. He is buried in Grove Street Cemetery, New Haven, beneath a massive sepulchre which shouts the single name ‘GOODYEAR’ (see Fig. 4.3).
5 The Battles of the Giants—Thomas Hancock The second giant in the story of rubber vulcanisation is Thomas Hancock, who was as unlike Goodyear as one could imagine. He lived in the same house most of his adult life, he never married but looked after his extended family of nine adopted nieces and nephews, he concentrated on one project at a time, made that work, hopefully made money from it, and researched new ideas in his very limited spare time. He also believed in patents, as we shall see (with one notable exception), and took out a total of fourteen relating to rubber and gutta-percha between 1820 and 1847. One thing he did share with Goodyear was the same fascination, although not obsession, with that sometimes sticky, sometimes brittle, and sometimes even useful material, rubber. Thomas Hancock was born in 1786 in Marlborough, Wiltshire, the third of twelve children born to James and Betty Hancock between 1780 and 1800. This was a remarkable family, although we know little of the children’s formative years except that, as was all too common at that time, several, including four girls, died either in infancy or when relatively young. Their father was a cabinetmaker, and it is probable that Thomas learnt the skills of that trade because sometime after 1815 he appeared in London with his brother John to set up business as a coachbuilder. Only
Tears of the Tree 46 one of his brothers, William, continued the family tradition of cabinet-making, but at least four more of the brothers, including John, deserve mention as having contributed significantly to Britain’s culture and industry in the nineteenth century. Walter, born in 1799, was an engineer who designed and built some of the earliest and most successful of the steam carriages which were appearing on the English roads in the early nineteenth century. Around 1840 he became disillusioned with the prospects for these vehicles and threw in his lot with Thomas, where his engineering abilities enabled him to work on the construction of various pieces of rubber processing and product manufacturing equipment. John, born in 1788, had his own rubber goods and hose factory, where he used equipment designed by Walter to make catheters and other products with medical applications. Unfortunately, he died of consumption in 1835, aged just forty-seven. He and his wife, Fanny, had continued the family tradition by having nine children between 1812 and 1828, but, when John died, Thomas took the children to live with him at his house, Marlborough Cottage (see Fig. 5.1), in Green Lanes, Stoke Newington, where three of them, remaining spinsters, lived after Thomas’s death until their own in 1895 (Fanny), 1902 (Maria), and 1909 (Harriet). A fourth child, John Junior, was a noted sculptor who exhibited at the Great Exhibition of 1851. He was a friend of Dante Gabriel Rossetti and the pre-Raphaelites, and helped finance their magazine, The Germ. Another of Thomas’s brothers, Charles (1800–1877), was a not inconsiderable artist whose works could be seen at the Royal Academy and to whom, incidentally, we must be grateful for his sketches of his siblings and mother. Although this book is concerned with natural rubber, it is worth mentioning that in 1843 Charles was to be introduced to gutta-percha, a material with the
The Battles of the Giants—Thomas Hancock
47
Fig. 5.1 Marlborough Cottage.
same chemical composition as rubber but with a different spatial configuration, by its discoverers, Drs Almeida and Montgomerie. Within a year he had taken out the first of a number of patents concerning its processing and use, including one for coating wire with it to form an electrically-insulated conductor. He founded The West Ham Gutta Percha Company with Henry Bewley and was soon selling a wide range of products, as well as sheet for others to fabricate articles from. By 1855 his catalogue listed over one hundred different products. The two separated and in 1860 Charles Hancock joined S. W. Silver & Company, bringing with him his patents and knowledge of gutta-percha, and entered the business of manufacturing and laying submarine cables through a new company—The India Rubber, Gutta Percha and Telegraph Works Company, Ltd. Their first cable was in 1865 and ran from Dover to Cap Gris Nez. This was followed in 1867 by a cable for the International Ocean Telegraph Company which linked
Tears of the Tree 48 Havana, Cuba to Key West and Key West to Punta Rassa. For almost fifty years they continued to lay cables across most of the oceans and seas of the world. With the loss of their last ship in 1915, the company withdrew from cable-laying and in the mid1920s became the Silvertown Rubber Company and, eventually, part of BTR Industries Ltd. By 1998 this company had become part of Dunlop Standard Aerospace Group. James, the eldest of the brothers, (1783–1859) married Elizabeth Lyne in 1811 and she gave birth to James Lyne Hancock in 1815. It was he to whom Thomas handed over his thriving company in 1842 and who ran it until his death in 1884 when it passed to Thomas’s grand-nephew, the son of Sarah (one of John and Fanny Hancock’s children) and John Nunn, John Hancock Nunn, who was then aged only twenty-nine. Thomas’s interest in rubber seems to have sprung from a desire to make waterproof fabrics to protect the passengers on his coaches, and he recalled that by 1819 he was beginning to experiment by making solutions of rubber in oil of turpentine, but was dissatisfied with the thin solutions which were all he could obtain and the poor quality of the films cast from them. It later appeared that the oil of turpentine was often impure and this led to the variability in solution properties. At about the same time he hit upon his first reasonably practical use of rubber. He was aware of its unfortunate habit of becoming sticky when hot and brittle when cold, but reasoned that the English climate was not too variable and if the rubber was to be worn close to the skin this should have a compensatory effect. His idea was to attach rubber strips (caoutchouc springs) to articles such as gloves or ‘any article of dress where elasticity is desirable at any particular part’, and this was the subject of his first patent dated 29 April 1820. In the patent he lets his imagination run riot as to the possible applications, clearly foreshadowing the vast range of
The Battles of the Giants—Thomas Hancock
49 applications he was to come up with in later life for this new material—rubber. Hancock does not say what source of rubber he initially used to make his elastic springs, but does say that they were sliced and sewn in place on the article to be elasticated. This taught him a new lesson which was that, although a piece of rubber could be stretched, if it was punctured with, say, a needle then it would quickly tear from that point and be useless. His initial answer to this problem was to cut the rubber thicker at the points of attachment and so spread the load around the holes, but he soon came up with a better solution when he realised that a good quantity of rubber was coming into the country in the form of thin-skinned rubber bottles. Here was the ideal material for him. Rings could be cut directly from the bottles, with different-sized bottles, or even different regions of the same bottles, providing the variety of sizes he needed for his multitude of applications. These could be enclosed within a rolled-over piece of the fabric without the need for actually sewing through the rubber itself, a practice which remains in use to this day. His second lesson in rubber engineering followed quickly and shows his abilities as an experimentalist. Many articles were being returned with the elastic springs broken, so he subjected a range of them to a cycle of stretching and relaxation under close observation. He saw ragged edges where the cutting had ‘nicked’ the rubber and that tearing propagated from these defective regions. He further noted that some of the bands did not tear under these conditions and realised that these were the ones which had been immersed in hot water after cutting, the heat allowing any fresh cuts to self-seal. This practice became the norm during his subsequent manufacture of the rings. His ability to observe and experiment would serve him well in the months to come as his new concern was that he was now
Tears of the Tree 50 generating a great deal of waste rubber from this process. The observation that freshly-cut faces of rubber blocks could be fused by simple pressure and a little heat led him to design a mould into which he could place freshly-cut blocks of rubber and compress them to provide a ‘standard block’ of rubber. This was a much more useful starting material for his ideas than the randomly shaped lumps or bottles then being imported. Although this observation had originally been made by Franc¸ois Fresneau and was common practice in the making of catheters in the eighteenth century, it seems probable that Hancock had come across it independently as the timescale between his becoming interested in rubber and observing this phenomenon was extremely short. However, he agreed with the earlier workers that this was a time-consuming process and not always successful, so he set his mind to designing a machine which would tear up any rubber placed in it into fine shreds which would then reunite to give him one homogeneous piece. Still in 1820, he built his first machine out of wood. It simply consisted of a hollow circular cylinder lined with iron spikes inside which was rotated (by hand) a smaller cylinder, again studded with iron spikes (see Fig. 5.2). The rubber shards were dropped into the gap between the cylinders through a ‘door’ in the top of the machine and the handle was turned. On opening the machine Hancock found that he had managed to fuse the shards into one lump of warm rubber, although this still showed graining from the separate pieces. He replaced it in the machine and continued mixing until he had determined how long it took to obtain a uniform ball or ‘slug’ of rubber. He was familiar with fibre-carding machines at that time from his interest in artificial leather, and it seems likely that his design of the pickle was influenced by these. This ‘one-man-powered’ machine would only take a charge of about two ounces of rubber, which was not particularly practical,
The Battles of the Giants—Thomas Hancock
51
Fig. 5.2 Hancock’s pickle.
so he immediately designed a larger one, this time made of cast iron, with suitable gearing so that one man could treat about one pound of rubber at a time (see Fig. 5.3). The patent claimed that: . . . in the course of half-an-hour, more or less, according to the speed of the shaft and the quantity of India rubber employed, the combined action of heat and friction, occasioned by the motion and pressure on the India rubber had the effect of uniting it into one compact mass or roll (F).
This is the masticator which he began using in 1821 but which was only described and illustrated in his 1837 patent entitled ‘Dough waterproofing’, to which we shall return later.
52
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Fig. 5.3 Hancock’s first metal pickle.
Rubber technology had arrived in the shape of the highly secret ‘pickling machine’, or masticator as we know it today. He soon advanced this to a horse-powered machine (fifteen pounds), and by 1840 his masticator could handle charges up to two hundred pounds. It should be noted that he chose not to patent his ‘pickle’, this being the one time that he preferred to rely on secrecy— an important point which will be returned to later. Both his earliest wooden prototype and his first cast-iron machine remain in existence today, the former in the Science Museum of London and the latter in the care of the Plastics Historical Society.
The Battles of the Giants—Thomas Hancock
53 As soon as Hancock had prepared his ‘pickled’ rubber he began experimenting further with rubber solutions, and in 1824 and 1825 he took out three more patents, processes for making artificial leather and for waterproofing ropes and cordage. Interestingly, the first and third of these three patents required the use of latex, which was extremely rare in Europe, as the waterproofing adhesive, although he does not use the word ‘latex’ but talks of this ‘juice’ being identical, when dried, to caoutchouc or India rubber. His choice of solvent for the middle patent, a mixture of highly rectified coal-tar oil and oil of turpentine, was probably influenced by Charles Macintosh’s patent of 1823. In the same year he began collaborating with Macintosh on the manufacture of his ‘double-textured’ material. (It has to be observed somewhere that, whilst Macintosh’s name has no ‘k’ in it, his eponymous article of clothing has!) Macintosh (see Fig. 5.4) was a Glaswegian chemist who had a dyestuffs and mordant business. In 1819 he entered into a contract with the Glasgow Gas Works to relieve it of its waste coal tar, which resulted from the company’s gas manufacturing process. Macintosh wanted the coal tar for its ammonia, but was probably familiar with Syme’s work and realised that he could obtain coal tar naphtha from his waste material. He dissolved rubber in this and came up with the brilliant idea of making a three-ply material, comprising two layers of fabric bonded together with a middle layer of rubber. This was the process he patented in 1823, not the use of naphtha as a solvent, although the patent was the first to refer to this particular chemical. His new industry for producing double-texture waterproof fabrics was founded in Glasgow in 1824. In 1825 Hancock obtained a licence from Macintosh to use his patent, but realised that his own rubber solution, prepared from masticated rubber and a solvent mixture of rectified coal-tar
54
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Fig. 5.4 Charles Macintosh.
naphtha and oil of turpentine, was much superior to that of Macintosh—it was thicker and therefore required less solvent, it penetrated into the fabric less, and it dried to give a less malodorous material. At this stage Macintosh did not trust Hancock sufficiently to use his rubber solutions. However, by 1830 it was obvious to all that Hancock’s solution was significantly superior to that of Macintosh, and so full cooperation between the two began, one feature of which was the construction of an automated
The Battles of the Giants—Thomas Hancock
55 spreading machine, probably designed by Walter Hancock, to replace Macintosh’s paintbrushes. At this time Hancock was working with Macintosh, but with a contractual relationship limited to Hancock supplying the rubber solution whilst he carried on his own independent business in Goswell Road, London (see Fig. 5.5). One aspect of his independence was that he was invited to set up a complete manufacturing facility in Paris for Messrs Rattier and Guibal, what today we would call a ‘turn-key’ operation. He supplied the equipment and workers, including a manager, Mr Edward Woodcock, who must have found the life there most convivial because he remained there until at least 1857, when he received a copy of Hancock’s Narrative and wrote a very appreciative reply. It is of interest to note how many of Hancock’s employees stayed with him for many years. Edward had a brother,
Fig. 5.5 The Hancock factory, Goswell Road, 1850.
Tears of the Tree 56 Alonso, who was also working with Hancock at the time that Edward went to Paris and he could be found in 1858 as works manager of Chas. Macintosh and Co. in Manchester. Initially, Hancock kept his mastication process confidential but contracted to supply his solution. Production started in late 1828 and the goods were sold through a shop specially opened by Rattier and Guibal. Hancock also had a share in his brother John’s medical goods and hose manufacturing company, but John sold his share in the company to Chas. Macintosh and Co. in 1833 when he was forced to move to Cornwall because of ill health. In 1834 Hancock’s London factory burnt down, so it was agreed that he would do likewise with his share in John’s company in return for a formal partnership in Chas. Macintosh and Co. Ltd. Almost as soon as Macintosh had started in business in 1824 he had received some large government contracts, so he needed both more space and a reliable source of fabrics. He therefore entered into an agreement with Hugh Hornby Birley and his brother, Joseph, who were cotton spinners based in Manchester, whereby they would build a new factory to make the waterproof material. This gave him the base on which he could now build by closing the Glasgow factory and moving all of his rubber business to Manchester. The factory he actually moved into had been substantially designed and equipped by Hancock in around 1830, and it is interesting to note that Macintosh investigated the possibilities of solvent recovery from the drying cylinders but decided that it was neither commercially viable nor a particularly useful exercise. The new company had as its directors Macintosh, Hancock, the Birley brothers, and William Brockedon. We shall meet Mr Brockedon again but can note here that he had started life as a watchmaker, turned to art, and then became an inventor who, as well as being involved with natural rubber, also invented a process for compressing graphite for ‘lead’ pencils.
The Battles of the Giants—Thomas Hancock
57 Hancock, however, remained in London, rebuilt his London base, and continued to manufacture airproof and waterproof cloths and products there, whilst the mastication and preparation of the rubber solutions was carried out in Manchester. The Manchester factory was equipped with steam power to drive the ever larger and more numerous machines, but the first steam engine ever to be used in the rubber industry was installed in Hancock’s Goswell Road, London, factory in 1836. Here it remained in use until 1922. It was known as the ‘Grasshopper’ (see Fig. 5.6). Just as things were settling down it was Hancock’s and Macintosh’s turn to go to law. The first of their major UK cases took place in 1836, with Chas. Macintosh & Co. as plaintiffs and
Fig. 5.6 The ‘Grasshopper’, built by Easton & Amos, 1822.
Tears of the Tree 58 Wynne Ellis as defendant. The plaintiffs’ case was that Everington and Ellis had infringed Charles Macintosh’s patent of 1823 for the manufacture of ‘double-textured’ cloth. In 1824 Macintosh had approached Wynne Ellis, perhaps the richest silk merchant in the UK and an art collector of international renown whose collection later was to form part of the UK National Gallery, for financial backing for his new material. Some of Wynne Ellis’s silks had been treated at Macintosh’s factory in Glasgow, but he was not sufficiently impressed to help finance Macintosh’s expansion plans. However, in 1835, Everington and Ellis began to market ‘Fanshawe’s improved India rubber cloth’, which appeared in all respects identical to that manufactured by Hancock and Macintosh. The latter were just starting to make money and were not prepared to share it with interlopers! The situation was further complicated in that, whilst they were preparing their court case, they applied for an extension of the 1823 patent. The application was heard in December 1835 and it was ruled that a decision should be held over until 1837—after the pending court case. The case for Wynne Ellis was threefold in that evidence was produced that ‘double-textured’ garments had been produced in Demerara since the end of the eighteenth century using latex as the adhesive, that Charles Green had used rubber solution and the double-texture procedure to manufacture balloons, and that it was obvious by inspection of the current output from the Macintosh factory that it bore little resemblance to that produced in 1823, and therefore the process must be different and the patent could not apply. The first point was quickly dealt with (surprisingly) when it was agreed that what happened when using latex was not the same as when using a rubber solution. It was surprising because the plaintiffs had emphasised that the solution was not important but that the patent referred uniquely to the ‘double texture’ in
The Battles of the Giants—Thomas Hancock
59 combination with a solution. The second witness was quickly disposed of when it was shown that his ‘double texture’ was an overlapping of seams and that the rubber solution was just a mastic. This left the final point, which put Hancock and Macintosh in a difficult position since the whole manufacturing operation had been the subject of ongoing development and had been carried out in secrecy without the benefit of patent protection. Their first witness was an operative who had left the business in 1825 before Macintosh had moved from Glasgow to Manchester, and he knew only the original procedure so could give away no secrets; but they then had to produce the man who was currently in charge of the manufacturing operations and who knew the development of the spreading machinery. Because of Hancock’s passion for secrecy, however, he knew nothing of the composition of the solution, nor did he have any knowledge of the masticator. They got away with it and were victorious, but opposition to an extension of the patent was so great that they decided to withdraw it and, at last, opted for the only protection left—to patent both the masticator and the spreading machinery. Reading the patent today and knowing of the introduction of the masticator, and Macintosh’s initial (patented) preference for purified coal-tar naptha but subsequent change to Hancock’s thick viscous solutions prepared with naptha and turpentine mixed solvent, etc., one must doubt whether the same verdict would have been reached today. Macintosh was lucky to allow for the spreader by saying in the patent ‘ . . . with a brush or other suitable instrument lay upon the surface of each (fabric) a uniform layer . . . ’. But when it comes to the adhesive the patent appears to be very specific: . . . cemented together by means of a flexible cement . . . prepare the caoutchouc by cutting into thin shreds or parings and then steep it in the substance used in making coal gas, commonly called coal
60
Tears of the Tree oil . . . 10–12 oz to 1 gallon of oil . . . to give a thin pulpy mass . . . pass through a fine wire or silk sieve . . . resembles thin transparent honey . . .
It was only in 1837 that Hancock finally patented both his masticator and spreader in the same UK patent, which was his eighth in seventeen years. The title of the patent:‘ ‘‘Dough Waterproofing’’ and the ‘‘Specification of the Patent’’. . . for an improvement or improvements in the process of rendering cloth and other fabrics partially or entirely impervious to air and water by means of caoutchouc or India rubber’, would suggest that he hoped that its contents would pass unnoticed, although this subterfuge was highlighted by Moulton in a later patent case, as we shall see. The masticator included in this patent shows his earliest iron version, with the functional part as illustrated earlier in this chapter (Fig. 5.3). In 1838 another fire destroyed the Manchester factory, but a new one was quickly built and business continued as before although Macintosh’s 1823 patent had expired in 1837. A few years of profitable manufacture brings us to 1842, and it was in that year that Macintosh and Co. decided to withdraw their operations from London and agreed to sell what had been John Hancock’s hose and tube business to Thomas’s nephew, James Lyne Hancock. Thomas included his interest in the Goswell Road business in the deal and James ran it until his death in 1884. The complicated relationships between various Hancock and Macintosh businesses—part independent and part interdependent—inevitably gave rise to friction. No better example of this exists than the argument between James and Macintosh and Co. as to whether hose pipes and tubes were both covered in the sale agreement of 1842. Macintosh and Co. carried out the vulcanisation of all James’s products (which must have been an extremely inefficient process, the one being in London
The Battles of the Giants—Thomas Hancock
61
Fig. 5.7 The Chas. Macintosh & Co. shop in Charing Cross, 1840.
and the other in Manchester), and so knew exactly what he was making. An argument blew up late in 1849 with Macintosh and Co. refusing to vulcanise ‘solid rubber tube’ on the grounds that this was not hose pipe and thus not included in James’s manufacturing rights. Thomas was caught in the middle and came down firmly on his nephew’s side, eventually, on 22 April 1850, writing a two thousand word letter to Macintosh and Co. setting out with wit and irony the history and usage of the words ‘hose’, ‘pipe’, and ‘tube’ during more than three hundred years of English literature. Unfortunately, this is the last letter in the set of a dozen on this topic so, regretfully, the company’s reply is not available.
Tears of the Tree 62 Nevertheless, we must assume the Hancocks won as James’ company went from strength to strength, and on his death it was willed to Thomas’s grand-nephew, John Hancock Nunn. This brings us to what was to be the start of the most contentious period of Hancock’s life—the discovery and subsequent story of vulcanisation in the UK. The story begins in 1842. It is an established fact that Stephen Moulton brought samples of Goodyear’s vulcanised rubber to the UK as Goodyear’s agent, attempting to sell the unpatented process for a considerable sum of money. He had with him a few scraps of vulcanised material, but Hancock comments that when he saw them they were charred at the edges, so it seems obvious that Goodyear was not able to send (or even possibly make) top-quality samples to promote his process. Moulton took them to Chas. Macintosh and Co. in Manchester where there was little interest in investing serious money without a thorough knowledge of the process involved in making it. This was not just for chemical reasons, but also because they needed to understand the technology involved so that they could calculate any capital expenditure which might be necessary to implement the process. William Brockedon (see Fig. 5.8), a director of the company, then showed some of the material to Hancock who was in London. Hancock willingly admitted that he realised that the material contained sulphur and claimed that he had been experimenting with sulphur for many years himself but with no success. The fact that it was somehow possible to obtain the result he was after with this substance spurred him on to concentrate on it further. In his 1857 Narrative he describes how he carried out numerous experiments in his private laboratory at his home, Marlborough Cottage, through the winter of 1842/43 and into the summer of 1843 when he had to purchase ice to see if he had changed the properties of his strips when cold. He realised that
The Battles of the Giants—Thomas Hancock
63
Fig. 5.8 William Brockedon.
sometimes he had managed to effect what he called ‘the change’ he was looking for, but he was not yet sure of the ‘hows and whys’—very like Goodyear. However, he took advantage of the English patent laws which allowed an inventor to apply for a preliminary patent to protect his interests after his first discoveries, and then six months to clarify points of detail before the patent became final, or enrolled. It was during this time that his friend and colleague, Charles Macintosh, died. During those six months Hancock carried out what were possibly the first systematic design experiments in the field of chemistry. He began by immersing rubber strips in molten
Tears of the Tree 64 sulphur and removing them after varying periods of time. Here he observed the previously unknown dissolution and steady migration of the yellow sulphur through the rubber section until the colour was uniform throughout. Nothing had happened to the physical properties, however, so he than began raising the temperature, again studying the samples periodically, and eventually removed one sliver to find that it had undergone the change he was looking for. He further noted that slivers which remained even longer in the sulphur had turned ‘black and horny, thus at once and indubitably opening to me the true source and process of producing the ‘‘change’’ in all its states and conditions, and in its pure and pristine simplicity’. He immediately appreciated that his existing equipment would enable him to process sulphur-treated rubber either dry or in solution before vulcanisation. With the information he had gathered, such as ways of adding sulphur and the time– temperature relationship of curing or vulcanising, he was able to get his final patent enrolled on 21 May 1844. It is a remarkable and all-embracing document describing various ways of adding sulphur—in the dry using his masticator or a mill in the same way that he was adding inorganic powders, or by immersing the masticated rubber in molten sulphur—together with subsequent spreading and moulding options as well as time: temperature:thickness correlation data for optimum curing or vulcanising. Ways of removing excess sulphur after vulcanisation are also discussed. Whilst Goodyear may well have been the first person to vulcanise rubber, he certainly had no control of his process at the time of Hancock’s patent, when the latter was able to illustrate his complete understanding and control of the chemistry. It was at this time, when his small-scale experiments moved from his private laboratory to the factory at Manchester, that
The Battles of the Giants—Thomas Hancock
65 William Brockedon came up with the name for the process— ‘vulcanisation’. The truth about Hancock and his ‘discovery’ of vulcanisation is unlikely ever to become clearer, although, given his Christian upbringing and reputation for honesty and fairness amongst his workers, there is no reason to doubt his version of events. Let his employees have their say. When he retired in 1858 he was presented with an illuminated address, written by a committee of employees, the grammar of which an unknown director would later apologise for to Hancock. The first two paragraphs read: WE, the operatives in the employ of Chas Macintosh and Co., cannot permit the opportunity to pass of your retirement as partner in the above firm, without expressing our heartfelt gratitude for the kindness, generosity and benevolence which you have so liberally bestowed upon us while in your employ. THERE are many of us who have for a long series of years witnessed your Christian forbearance, mildness of council and impartiality which have assumed more the character of an indulgent parent than an employer.
Some, who had been unable to append their signatures to the original address for various reasons, later wrote asking that their names should be associated with the sentiments expressed therein. It should also be noted that a number of chemists swore that, even if he had analysed Goodyear’s vulcanised material, this would not have given him enough information to manufacture it. Moulton, however, claimed that some of Hancock’s employees did carry out the analyses and one Mr Cooper had sworn that he was one who did. Alexander Parkes, the inventor of the ‘cold-cure’ process, went one step further and claimed that both Hancock and Brockedon had admitted to him that their
Tears of the Tree 66 experiments on the Goodyear vulcanisates had enabled them to understand what he had done, although how this statement differs from Hancock’s—that he realised sulphur was present and pursued the matter until he had obtained his ‘cure’—would appear to be one for the pedants. Whatever the truth, the fact remains that Hancock beat Goodyear to the Patent Office by some eight weeks and did nothing illegal or underhand. His understanding of the ‘cure’ or vulcanisation process and his ability to control it was certainly much more advanced than Goodyear’s. There also exists one report that Goodyear visited Hancock at Marlborough Cottage in 1843 and was entertained there on later visits. It claims that they were said to be firm friends, a relationship which would be difficult to understand if Goodyear had believed that Hancock had acted unethically. In November 1845 there was a rearrangement of partners at Chas. Macintosh and Co. George Macintosh, Charles’s son, and Henry Birley retired, and the remaining directors were identified in the ‘Notice of Dissolution of Partnership’ as Thomas Hancock, Richard, Thomas H., and Herbert Birley, and William Brockedon. Soon after, in 1846, the company purchased from Alexander Parkes his patent for the vulcanising of single-texture fabrics by a ‘cold’ process using sulphur chloride in carbon disulphide solution for £5000, and this added the final string to the company’s vulcanising empire. The company flourished and it is hard to find an article today which is made of vulcanised rubber and which does not feature in Hancock’s Narrative. The one notable exception is the pneumatic tyre which, although normally associated with John Boyd Dunlop’s invention of 1888, was first invented by R. W. Thompson in 1845. As well as describing hard rubber (vulcanite or ebonite), Hancock also mentioned blown sponge, although the latter never achieved significance during his lifetime.
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67
Fig. 5.9 The Chas. Macintosh & Co. trademark—HAN (d) COCK.
There were, however, still legal battles to be fought. In 1847 the first major shipment of vulcanised rubber products, mainly rubber overshoes, arrived in the UK from the States. This had the potential to undermine the position of Chas. Macintosh & Co. and had to be contested on the strength of Hancock’s prior patent. This was found to be valid and Macintosh & Co. granted The
Tears of the Tree 68 Hayward Rubber Company of Connecticut sole rights to import and sell vulcanised rubber footwear in the UK (for a consideration). In 1849 Chas. Macintosh & Co. began to prepare a case against a UK importer who was bypassing Hayward and, yet again, Hancock’s patent was found to stand. With these decisions in his favour, Hancock felt able to challenge the biggest thorn in his side—Stephen Moulton—who was manufacturing vulcanised rubber goods from his factory in Bradford-on-Avon. Stephen Moulton (1794–1880, see Fig. 5.10) is ‘the forgotten man’ of the UK rubber industry who seems only to be remembered as the man who brought samples of Goodyear’s vulcanised rubber to England and who passed some of them, via Brockedon, to Hancock. In fact, he became a major UK competitor to Hancock and was also responsible for opening up the south-west of England to the infant rubber industry. Moulton was born in County Durham in 1794 but his family was not North Country; indeed, his parents were both Londoners, where his father ran a law stationary business.
Fig. 5.10 Stephen Moulton.
The Battles of the Giants—Thomas Hancock
69 Mrs Moulton was visiting her sister when Stephen arrived! Like Hancock, his early life is undocumented, but in December 1826 the records of St George’s Church, Hanover Square, show that he married Elizabeth Hales of Somerset. The union produced nine children. Unusually, all of these survived to adulthood. We next hear of him in 1839, in America, living in New York and described as ‘a broker’. It was here that he met Goodyear, Hayward, and the Rider brothers, who were rubber manufacturers. It was through these relationships that Goodyear asked him to return to England and attempt to persuade some members of the British rubber industry to put up capital to develop his improved rubber products. Having failed in this project, Moulton returned to the US but remained bitten by the rubber bug, so much so that in 1847 he returned to England, determined to set up his own rubber goods factory. He had no desire to pay either Hancock or Goodyear royalties for the use of their patents, so he entered into an agreement with the Rider brothers and a chemist called James Thomas. This agreement allowed him to use the US rubber factory of the Rider brothers for development work, whilst James Thomas would allow him to patent in the UK his vulcanisation process using lead hyposulphite instead of elemental sulphur. They would have a share in Moulton’s profits from the patent. Unfortunately, the patent seemed to be based more on hope than proven results and it took two years of experimentation before Moulton succeeded in developing it to a practical conclusion. Although it had originally been agreed that the patent would be funded by the Rider brothers and that this would be repaid from future profits from the products manufactured in England, the Riders suffered from a downturn in the US economy and refused to financially back Moulton further, causing him, in late 1848, to go into the manufacturing business on his own.
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The location he chose was unusual in that it was in the west of England, far removed from the more usual centres of industrial activity, and was a disused woollen mill, the Kingston Mill, in Bradford-on-Avon, Wiltshire. Nevertheless, it had a wealth of advantages: coal from Somerset, the river Avon alongside the mill to supply power and washing water, the closely adjacent Kennet and Avon Canal, and the Great West Road to provide access to London. It was cheap and contained within the eight acre site ‘Kingston House’, which would provide the family home. Now that he had committed himself, the Riders were willing to offer him non-financial help, and so provided both advice and lent him the engineer who had built their machinery so that he could oversee the fitting out of Moulton’s factory. It thus became one of the first factories in the UK to be conceived and equipped as one complete unit. At that time it was not possible to buy much of the equipment needed, so some was built on site and some was manufactured by iron foundries to Moulton’s design. By 1850 Moulton and the Riders had a joint manufacturing agreement in place, but Hancock was not prepared to stand by and see his monopoly disappear without a fight, so it was back to the courts. He was, however, busy with the company’s large display stands at the Great Exhibition of 1851, where, as has already been said, he was in competition with Goodyear. An indication of the display presented by Chas. Macintosh and Co. can be obtained from Hancock’s Narrative: The year 1851 brought with it the memorable Crystal Palace and the ‘Great Exhibition of the Works of the Industry of all Nations’, and we were not slow in availing ourselves of this opportunity of exhibiting such a general collection of rubber manufactures as the world had never before seen; comprising specimens of almost every article to which the substance had been applied. Whether adhesive or unadhesive, vulcanised or unvulcanised, possessing
The Battles of the Giants—Thomas Hancock
71
elongating elasticity, or rendered rigid by hard vulcanising. Plain, coloured, printed, embossed, moulded portraits [see Fig. 5.11]. Medallions [see Fig. 5.13a], tablets, stick and umbrella handles, mechanical applications, toys and various other things made entirely of rubber, and ordinary and coloured solutions were also there, to which must be added some beautiful specimens of rubber produced by the converting process of Mr. Alexander Parkes. Of course we had also all the well-known Macintosh articles, Such as cloaks, capes, of double and single textures, airbeds, pillows, cushions, life-preservers, model pontoons, diving dresses, gas-bags, &c., &c.
This activity meant that Hancock could not take Moulton to court until after the exhibition. Here Moulton claimed that his patent of 1847 in which he used ‘lead hydrosulphite and artificial sulphured of lead’ did not infringe Hancock’s patent which just used sulphur, or Goodyear’s which used lead oxide and
Fig. 5.11 Rubber moulding of a pastoral scene which may have been shown on the Hancock stand at the Great Exhibition of 1851.
Tears of the Tree 72 sulphur. He also mixed ‘in the dry’, whereas Hancock’s patent was solely concerned with applications of solutions of rubber (not true), and there were other differences of varying importance which had allowed the patent to be granted. He further raised the point that Hancock’s patent was, in any event, invalid because its deposit paper of 1843 was not followed through in the final specification. As we have already seen, the title was: . . . For improvements in the preparation or manufacture of caoutchouc in combination with other substances, which preparation or manufacture is suitable for rendering leather cloth and other fabrics waterproof, and to various other purposes for which caoutchouc is employed.
The text begins with: . . . Preparation or manufacture of caoutchouc in combination with other substances, consists in diminishing or obviating their clammy adhesiveness and also in diminishing or entirely preventing their tendency to stiffen and harden by cold and become soften or decomposed by heat, grease and oil.
The eventual decision of the Vice-Chancellor’s court was unusual. The judge found for Hancock on all counts but pointed out that, because he had taken so long to bring Moulton to court (1847– 1852), he felt unable to make an injunction against Moulton, but ordered the motion to ‘stand over’ so that the plaintiffs could take further action if they so wished. Whether by coincidence or planning, it was shortly after this that Hancock had published by James Barclay of London a book which contained reprints of all the fourteen patents which he had taken out between 1820 and 1847. The book was comprehensively indexed and would suggest that he was setting out his position: This is where I stand. Certainly you can use my process to manufacture any of
The Battles of the Giants—Thomas Hancock
73 these (or related) products. Just remember to ask first and pay for a licence. Moulton was extremely unhappy with this outcome, not least because he continued to harbour a dislike of Hancock, believing him to have stolen Goodyear’s ideas and failing conspicuously to give him credit for the original discovery of sulphur vulcanisation. However, he now was able to manufacture a wide range of goods and he specialised in industrial and engineering applications, although his records show that he continued to produce rubberised fabrics, beds, and cushions through to 1880. The major products of the company were railway and carriage springs which, together with other railway-related products, grew from 30% of output by value in 1860 to 85% by 1890. The growth was due, in considerable measure, to Moulton’s patented (1861) suspension unit, which consisted of a coiled spring embedded in a block of rubber. Other areas of importance were hoses, sealing washers, and valves. Perhaps surprisingly, the company never showed much interest in rubber tyres, although the pneumatic tyre was not patented by Dunlop until eight years after Stephen Moulton’s death, whilst the other potential growth area, footwear, was bedevilled by patent restrictions. The company flirted with rubberised conveyer belting in its early days, but dropped out of this market due to the intense competition and low profitability by the time of Moulton’s death. In 1891 the company amalgamated with George Spencer of London to become Spencer Moulton. This company continued until 1956 when it became part of the Avon Rubber Company. Production ceased on the site in 1993. There is a footnote to the story of Stephen Moulton; his great-grandson is Dr Alex Moulton (born 1926), who is also famous for his involvement with rubber in engineering. Not only did he develop the Moulton bicycle with its rubber suspension, but also
Tears of the Tree 74 the rubber suspension used in the Mini, which further developed into the hydroelastic system used initially in the 1100/1300 Austin/Morris series, then in the Rover 100 series, and currently in the MGF sports car. Let us now return to the trials of Thomas Hancock and Chas. Macintosh and Co. The American shoe trade was not at all happy with Hancock’s victories and the indecisive verdict in the case of Hancock versus Moulton so a Mr Ross, who was importing American shoes into the UK but not via Hayward, challenged Macintosh & Co. to sue—which Hancock duly did. After all the old ground had been gone over again the jury failed to reach a verdict, but the fighting spirit of the anti-Hancock group was high and they issued a writ of scire facias against Hancock, essentially putting the onus on him to provide evidence that he had actually carried out all the work described in his patent. The trial returned to court in mid-1855 and even Goodyear attended to stake his claim to royalties from Hancock should the latter lose. In the end it came down to one question. When Hancock had taken out his patent in 1843 had he understood and achieved vulcanisation? If he had only done this between 1843 and the final specification in 1844 then his patent would fall. In January 1856 the saga came to an end with the jury finding for Hancock, and Moulton was granted a licence to manufacture rubber products, excluding clothing and medical goods, for the sum of £600 per annum. Hancock was able to get on with his stand at the International Exhibition of 1855 in Paris. Somewhere in all this activity, Hancock found the time to write his magnum opus, The origin and progress of the CAOUTCHOUC or India-rubber manufacture in England, which was published in 1857 and sets out in great detail his business-related life from 1820. It includes many illustrations of his products as well as page upon
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75
Fig. 5.12 The Chas. Macintosh and Co. factory in Manchester as it was in 1857.
page of listed products with their descriptions and uses for the benefit of the uninitiated. The patent specifications are also appended. A particularly interesting section tabulates the exports of rubber from Para´ to cities throughout the world from 1837 to 1856, as well as total rubber imports to, and exports from, the UK during the period 1842–1855. To quote just one statistic, the total imports of rubber into the UK in 1842 were around 140 tons, but had risen to 2235 tons by 1855. These figures accounted for about half the output of Amazonia. Some of that was traded on. In 1842 about 10% left the country as the raw material and this had risen to over 18% by 1855. Nevertheless, the growth of rubber product manufacturing in the UK over this period was phenomenal—and we still did not have the motor car with its demand for tyres! James Lyne Hancock authorised a reprint of the Narrative, without the patent appendix, in 1920 to celebrate one hundred years of the company’s existence. Hancock sent copies of his book to many of his friends and business colleagues but there is no record of one going to Charles
Tears of the Tree 76 Goodyear. However, one was sent to Nathaniel Hayward with an attached letter which is reproduced in full below. Stoke Newington. N. 27th. Jan Y. 1857. Nathaniel Hayward. Esq., Dear Sir. Considering the position you are entitled to take amongst the foremost in the manufacture of India Rubber in the United States I have thought that having written a simple narrative of the part which I have taken in its manipulations in this country a copy would not prove unacceptable to you. I have therefore forwarded one to your address of which 1 beg your acceptance. If you have not already done the same thing in America no man I should think is more able or more entitled to fulfil such a task. I indulge the hope that although fast declining into the vale of years I may yet live to see such a production emanating from the press under your hand. With the expression of every good wish to you as a Fellow labourer in the same pursuit, I am, Dear Sir,
One wonders why Hancock chose to write to Hayward in this way. He could not have read Goodyear’s book, only a very few were published, but he might well have heard comments from America that Goodyear felt, at best, put out by Hancock’s patent and subsequent victories in court. Did he think that Hayward could add some revealing background to the very incomplete story of Goodyear’s discovery of vulcanisation? Of equal interest is that he chose to send a copy of the book to Horace Day, writing inter alia: . . . I have written a Narrative of the part I have taken in the Rubber manufacture in England . . . If a similar narrative of an authentic character has been published in the United States I should feel very much obliged if you would be so good as to send a copy to me.
The Battles of the Giants—Thomas Hancock
77 (The underlining is Hancock’s.) Did he know of Goodyear’s book and was making some derogatory implication or was he unaware of its existence? He also found time, with considerable prescience, to send a copy of his book to the first Keeper of the Royal Botanic Gardens at Kew, Sir W. J. Hooker. Having previously, and to no avail, sent an employee to Para´ to try and persuade the tappers and collectors to improve the quality of their material, he suggested that consideration should be given to creating plantations in either the East or West Indies. Hooker replied, mentioning that he knew Macintosh as they had been in Glasgow at the same time and adding that he had already asked his agent in Brazil to acquire seeds from the best rubber trees for germination at Kew. Unfortunately, he was not successful and a generation was to pass before this was to be finally achieved. This is a generation gap which, if it had not occurred, could have substantially altered history, as we shall see. This is not quite the end of Hancock’s story because someone discovered that there were two patents by Goodyear and Hancock covering the UK. In England Hancock’s preceded that of Goodyear by some two months, but in Scotland the position was reversed with Goodyear’s application dated three months ahead of that of Hancock and the final specification being just one month ahead. In 1856 the North British Rubber Company was founded in Edinburgh, being shipped over, lock, stock, barrel and key workers, from the US. Legal opinion was that Hancock’s delay in filing his Scottish patent would probably lead to defeat if he went to court and, since it had so little time left to run, the battles at last ceased. Hancock’s very abridged reports of his trials in his Narrative paint him very much as the injured party just trying to protect his interests, whilst the rest of the rubber world is bent on destroying him and the monopoly he aimed to obtain in the UK. How
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78 (a)
(b)
Fig. 5.13 Thomas Hancock: (a) an ebonite medallion, and (b) a portrait.
The Battles of the Giants—Thomas Hancock (a)
79
(b)
Fig. 5.14 (a) Hancock’s memorial in Kensal Green Cemetery, and (b) the inscription on Hancock’s memorial.
justified he was in holding those beliefs the reader must judge, but what is certain is that without Hancock’s drive and inventions between 1820 and 1850 the UK rubber industry would never have achieved the advancements it did, and the UK would be a worse place for that. Thomas Hancock died at his house in Green Lanes, Stoke Newington, on 26 March 1865 and was buried in Kensal Green Cemetery (see Fig. 5.14). He left just over sixty thousand pounds, a not inconsiderable sum, but only a fraction of what he might have made if he had been the hard uncaring money-grabber that some have made him out to be. On 7 April 1865 The Mechanics’ Magazine published a thirteen-hundred word obituary. The house survived in the care of his three spinster nieces until the last one died in 1909, after which it had a chequered
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Fig. 5.15 Plaque erected on the site of Marlborough Cottage, 2003.
history until 8 January 1945 when a German V2 rocket exploded in the next door meadow. The house was terminally damaged and soon afterwards demolished. In its place was erected a block of flats, but Hancock’s contribution to the UK rubber industry remains for all to see in the form of a plaque erected on the site by the Plastics Historical Society in 2003 (see Fig. 5.15).
6 Rubber goes East It is probably useful to note at the beginning of this chapter the location of the Hevea or Para´ rubber tree which was, and still is, believed to provide the best rubber. With two very small exceptions, it is confined to the land south of the River Amazon, dropping from its estuary at Bele´m to about 15 south, then swinging west to the border between Peru and Bolivia, before swinging round in a great loop taking in about one-third of Peru, before rejoining the Amazon where Brazil, Peru, and Colombia meet. The two exceptions are a small looped incursion to the north-west of Manaos (today known as Manaus) and a triangular excursion north of the estuary delta 1 or so north of the equator. Between 1851, the year of the ‘Great Exhibition’ in London, and 1855 a Scottish explorer, Richard Spruce, was searching for new plants in the Amazon basin. Thousands were brought to England but he did not bring any Hevea seedlings as he knew that these would not survive the long journey home. He thought of bringing some seeds back but found that these quickly turned rancid after collection, so he abandoned that idea. He did, however, make detailed studies of the tapping and collecting procedures adopted by the natives and noted that the price (demand) was rising rapidly. He also realised that the tappers were essentially slaves, given advances for tools and food which were to be paid off against future earnings. The high prices
Tears of the Tree 82 demanded for the former and low prices paid by the traders to the tappers for their rubber ensured that this would be a very long process. Given the high death rate amongst the tappers due to disease and malnutrition, it was more likely to be ‘never’. It is worth remembering that Thomas Hancock had sent one of his employees to the Amazon basin in an attempt to persuade the dealers to supply cleaner rubber. Obviously, the incentives to the tappers were few and it was not uncommon for pelles or smoked balls of rubber to have a stone inserted in the centre to increase their weight and hence selling price (see Fig. 6.1). At the same time that Spruce was travelling in the Amazon basin, a young naval officer called Clements Markham was devoting two years of his life to journeying around Peru, and here he noted two unrelated things which were to have a significant effect on his career and the future of the industrial world. The first
Fig. 6.1 A smoked ball of rubber (pelle) being cut in half in Para´ to check quality.
Rubber goes East
83 was the cinchona tree, from the bark of which is extracted quinine, and he determined to transplant this to India for the treatment of the tropical diseases which were rampant there and which posed a bigger threat to the lives of the British soldiers and families than did actual warfare. The second was the death of the rubber-producing trees due to massive over-tapping when numerous cuts were made simultaneously in the bark of the same tree. When he returned to England he obtained a position in the Civil Service and spent the next few years organising the movement of the cinchona tree to India via the Botanic Gardens at Kew with the help of one of their staff, Robert Cross. For this work Markham was later to be awarded a knighthood. The transplantation required further journeys to Peru and in 1865 he was in India and Ceylon (Sri Lanka) checking on his trees. Here he found that the lust for rubber was being met by the slaughter tapping of India’s rubber plant—ficus elastica. It was then that he became the first person to realise that ‘wild rubber’ would never be able to meet the ever-increasing demand of the industrialising nations. He wrote to the India Office suggesting that rubber plantations be established to meet this growing demand. No doubt his idea was that this should be a British exploit on Britishcontrolled land and India would meet the bill nicely. Markham’s letter remained on file and on his return he was promoted before going to Abyssinia with the 1867–1869 expedition, after which he returned to spend two years preparing detailed maps from his notes. Time was passing, but in 1870 Markham decided that he must act. When it is considered that every steam vessel afloat, every train and every factory on shore employing steam power, must of necessity use India-rubber, it is hardly possible to overrate the importance of securing a permanent supply, in connection with the industry of the world.
Tears of the Tree 84 He had seen papers published by James Collins, who was then the curator of the museum of the Pharmaceutical Society, on rubber and realised that here was a man with a knowledge base which should be tapped. He therefore commissioned him to write as detailed and as comprehensive a report on all aspects of rubber production as possible, and this was completed in 1872. The report favoured the collection of Hevea seeds and was circulated to several interested parties, one of whom, Dietrich Brandis, supported Collins’s idea and suggested southern India or Ceylon as good locations for possible plantations. Markham was now moving fast and sent his old and trusted previous ‘partner’, Robert Cross, to the Amazon to collect seeds. In 1873, after discussions with Sir Joseph Hooker, Director of the Botanic Gardens at Kew, he requested the Foreign Office to ask the British Consul at Bele´m (also known as Para´, the capital of Para´ State) to send some seeds of the Hevea tree to Kew. He suggested that a certain Mr Wickham at Santarem might carry out the collection as he had previously written to Hooker offering to supply Kew with botanical specimens. In the meantime, the first rubber seeds had turned up in London. In Collins’s second publication he had asked readers to send him any new information which they might have on rubber. Along with that feedback came an offer from Charles Ferris to sell him some two thousand freshly collected seeds. The news was passed to Markham who purchased them on Kew’s behalf, where they were planted. Unfortunately, only twelve germinated and these soon died, although six survived long enough to be the first Hevea ever to arrive in India. They were delivered to the Calcutta Botanic Gardens and the lesson learnt from this was that any more should be sent further south, to warmer climes. Whilst waiting to hear from Wickham, Markham had been offered seeds by a Bolivian, Ricardo Cha´vez. These arrived in
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85 mid-1875 when Markham was away from his office. No one knew what to do with them, and by the time any decision was reached they were useless. This brings us to ‘a certain Mr Wickham’. At about the time that Thomas Hancock was writing to Sir William Hooker, the then Director of the Botanic Gardens at Kew (who was followed in this post by his son, Sir Joseph, in 1865), about the possibility of the UK starting some form of rubber plantation industry, there was the young Henry Alexander Wickham who was a ten-yearold boy with his life before him. He was the eldest child of Henry and Harriette (ne´e Johnson) Wickham and was to have two siblings, Harriette Jane and John, the latter being born after Henry senior had died in the London cholera epidemic of 1850. The death of Henry senior left the family in dire financial straits as there was no private income, and Mrs Wickham had to work as a milliner to support them. It is perhaps inevitable that Henry was somewhat spoilt and had an unexceptional schooling and early life. He showed some talent for sketching and painting and this was to provide a pictorial insight into his later travels. He was also reportedly good at fishing, which may have given him a grounding in many of the ‘fisherman’s tales’ he would come out with later in life. In 1866, aged twenty, he set out for Central America. Possibly he had been inspired by the stories of Robert Cross concerning his exploits in bringing the cinchona tree from South America in 1860. Wickham arrived in Nicaragua on 22 October and from there he travelled up country to spend nine months catching exotic birds, the feathers of which he sent to London for the ladies’ hat trade—possibly to his mother. By the end of the summer of 1867 he was back in England. A year later saw him in the Orinoco Delta and, again, he travelled up country tapping wild rubber trees, eventually crossing to the River Negro which
Tears of the Tree 86 led him to Manaus, strategically positioned at the River’s confluence with the River Amazon. As the crow flies, Manaus is about eight hundred miles inland, due west from Bele´m (Para´) (see Fig. 8.2). By river it is considerably further! He followed the Amazon to Para´, where he met the British Consul, James Drummond Hay, who had written a report on the socioeconomic climate of the region with particular reference to the profits being made by rubber collecting. Wickham gave a full transcription of the report in his first book, published in 1872, entitled Rough notes on a journey through the wilderness from Trinidad to Para´, Brazil, by way of the great cataracts of the Orinoco, Atababo and the Rio Negro. From Bele´m he shipped to England, noting that: I have come to the conclusion that the valley of the Amazon is the great and best field for any of my countrymen who have energy and a spirit of enterprise as well as a desire for independence.
One has to wonder at his enthusiasm when his notes tell of sandflies, mosquitoes, tropical rainstorms and almost unbearable heat, semi-starvation, and malaria. Nevertheless, he vowed to return to Santarem, located at the confluence of the Tapajos and Amazon rivers, about three hundred and fifty crow miles and five hundred water miles inland, for his next adventure. Back in England he married Violet, daughter of W. H. J. Carter, who was a publisher with a bookshop/library in London and who, it is generally believed, financed much of Wickham’s later travels and (mis)adventures. Soon after the wedding, in the summer of 1871, they set sail for Santarem, accompanied by Wickham’s mother, sister Harriette, and brother John. A sketch by Wickham of their first house survives in the New York Public Library and shows a very primitive wood-framed shack with thatched roof and walls. Harriette and John were both married in Bele´m in July 1873, but by 1876 Mrs Wickham senior,
Rubber goes East
87 Harriette, and John’s mother-in-law had all been killed by the Amazonian climate. Wickham had taken with him from England some labourers with the idea of growing sugar, manioc, and tobacco (rubber was not yet in the picture), but they soon deserted him and he was forced to move several times in a search for reliable workers. Eventually, the family returned to Santarem where there was a group of ex-confederate soldiers who worked as a commune, thus avoiding the problems with local labour. All this time Wickham’s lifestyle was progressing smoothly downhill. In late 1874 he had been offered ten pounds for one thousand seeds by Markham but saw no point in putting himself out for such a sum. After much discussion within the India Office, this number was increased to ten thousand, and in April 1875 Wickham received a letter from Markham, through Hooker, offering ten pounds per thousand for as many as he could collect. The contract was supposed to include the words ‘viable seeds’, but ‘viable’ got omitted! Wickham pointed out that it was now at the very end of the seed-drop season so things would have to wait until the next season, nine months away. During the first six months of 1876, Wickham’s ‘extraction’ of some 70 000 rubber seeds from Amazonia and their transportation to Kew, via Liverpool, took place, but the complexities of this story are many and remain unresolved to this day. The story was told many times by Wickham, the first being in his book of 1908, On the plantation, cultivation, and curing of Para´ Indian rubber, with more and more added refinements until his death in 1928. Even the first version runs to seven pages but can be summarised as follows. The Amazonas, under Captain Murray, the first of a new line of Inman Line-owned steamships, had arrived at Santarem and he had received an invitation to dine on board. The ship then continued
Tears of the Tree 88 its voyage upstream to Manaus. He next heard that the ship had been stripped of its cargo and abandoned by two of its crew. Murray was unable to purchase any cargo for the return voyage to the UK, so he (Wickham) chartered it and arranged to meet it at Santarem, where he would load the seeds he had managed to collect. He then immediately set off by canoe up the River Tapajos and, working with as many natives as he could recruit, ranged the forests collecting seeds. The girls in the village made baskets or crates of split cane to receive the seeds, which were lightly dried and packed between layers of banana leaves to preserve their vitality. He also noted that he was working against time as, although the seeds would fall for a further month or so, he had his appointment to keep with Captain Murray and the Amazonas. He returned down the Tapajos, loaded the otherwise empty ship, and returned with his wife to Europe, dropping off at Le Havre to arrange for a train to meet the steamer when it docked in Liverpool and transport the seeds without delay to Kew. Unfortunately, Wickham’s story only states that he arranged to meet the Amazonas at Santarem ‘on a certain date’. We know the seeds arrived at Kew on 14 June 1876 and that the Amazonas docked in Liverpool on 10 June. We also know that he wrote to Hooker on 6 March claiming: I am now collecting Indian rubber seeds in the ciringals (areas of tapped trees) of the River Tapajos being careful to select only those of the best quality.
Unfortunately, the story just does not gel. First, there is the question of the origin of the 70 000 seeds themselves. Given that the Hevea trees were widely scattered throughout the tropical rainforest and not in tidy plantations, and that the seeds do not just drop but are ‘catapulted’ up to forty yards from their parent tree, could Wickham and a few helpers really
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89 have collected 70 000 seeds in a matter of days or had he been hoarding them since the dropping season began in January when he knew that he would get the contract? His wife also noted in her diary that he put out a call for seeds and was buying all he could get hold of (sources obviously unknown). He knew they had a very short ‘shelf life’ but, after all, he was going to make sure he was paid on the basis of ‘number delivered’, not ‘number germinated’. Secondly, there is the question of the ship. The Amazonas was built in 1874 by A. Simey and Co. at Sunderland for the Laing family, and was first registered in 1875. She was almost immediately sailing under the Inman line flag, where she was captained by George Murray, a man in his mid-thirties. During the time of interest to us she had made two voyages to Brazil. She had sailed from Liverpool on 24 December 1875, arrived in Para´ on 19 January 1876, continued to Manaus, and then returned to Para´ on 15 February. She was home in Liverpool on 14 March. She set sail again on 25 March 1876 with many of the same crew and, although there are no records of her times in Brazil, we can assume she arrived in Para´ in mid-April, and was back there close to 10 May since she was certainly home on 10 June. These dates do not fit with Wickham’s letter of 6 March; nor does the conclusion that the Amazonas must have been at Santarem in early May fit with Wickham’s comment that there was still one month or so of seed-drop time left to him, since this period finishes in late April, not June. The detailed crew records exist today and provide an interesting insight into seafaring at that time. The voyage was described in the agreement in considerable detail and, although it would take only a little over three months, the contract allowed up to twelve months. The food ration for each of the crew was listed (but could be varied at the master’s option). No grog was permitted on board and there would be no advances of pay until
Tears of the Tree 90 the voyage was complete. The Amazonas should have had a crew of thirty-two. One, Joseph Ceriney (?), failed to appear at the time of sailing, whilst another, James Coran (?), deserted when the ship docked at Havre four days later. Two more crew members joined at Lisbon: the surgeon, whose name is not legible, and a replacement able seaman, Alexander Lorrimer. The release documents show that the surgeon was signed off when the Amazonas returned to Lisbon on 1 June and all the other members of the crew were discharged with full pay on 10 June. Contrary to that part of Wickham’s story, none was missing and there were no adverse behaviour notes on any crew member. The Liverpool Customs Office bill of entry (see Fig. 6.2) shows the ship fully laden with most of her cargo (including 171 cases of rubber) being loaded at Manaus, well upstream from Santarem, although she did call at Obedos, some seventy-five miles upstream from Santarem, to take on board more cargo, including 819 bags of Para´ nuts. As one might expect, the goods were to be delivered to specified destinations. There was no question of the shipping line trading on its own behalf. Our problem now is that there is no record of the ship stopping at Santarem and there is no mention in the cargo manifest of rubber seeds. It is tempting to think that the ‘Para´ nuts’ could be rubber tree seeds, but we know that these were what we call today ‘Brazil nuts’. Also, there is no reason for Wickham to travel seventy-five miles upstream to Obedos when the ship would be passing his door less than a day later! It is worth calculating what we are looking for and, although all the figures are very much approximations, they do give some idea of the ‘package’. The weight of 70 000 rubber tree seeds is about 700 000 grams or three-quarters of a ton. Allowing for the banana leaf layers and the cases, the gross weight must have been nearer 1500 kg or one and a half tons. For the woven baskets to be
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91
(a)
(b)
Fig. 6.2 Bill of Entry for the SS Amazonas, Liverpool, 12 June 1876: (a) heading, and (b) details.
portable by the natives they would be unlikely to weigh more than 30 kg, so we are looking for a few tens (fifty?) of them. Converting 30 kg of seeds and leaves to volume gives a value of around 65 litres, which is close to a 40 cm cube or a 50 cm diameter hemispherical basket—a very convenient size to manhandle for the relatively small Amazonian natives.
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We must accept from Kew’s records that they were on this ship, but where and how? The problem we have with Wickham’s story is that we do not know the detailed source of all of the seeds he supplied or if, as his wife said, he actually bought some from the natives. If his collecting times were right, then the seeds must have been stored for a considerable period until the Amazonas was in the region of Santarem in early May, and how did he get them on board the ship? No documents have turned up to date which show that the India Office actually paid anything for the ship’s ‘charter’. Certainly, the Brazilians described Wickham’s actions as despicable and branded him a thief for carrying out an ‘exploit hardly defensible in international law’. In 1884 the state of Amazonas levied a massive export duty on rubber seeds, and in 1918 it banned the export completely, but in 1876 there were no restrictions in place. As early as 1861, a Brazilian, Joao Martins da Silva Coutinho, had suggested the formal cultivation of Hevea in plantations, and he repeated this in 1867 when he was the chairman of a jury examining the quality of rubber from sources throughout the world. This was picked up by Collins and included in his report to Sir Clements Markham. Interestingly, and in complete contrast to their attitude to Wickham, Brazil glorifies to this day the names of Francisco Inocentcio de Souza Coutinho, who smuggled seeds of many spices from Cayenne to Para´ in 1797, and Francisco de Melo Palheta, who, in 1727, had been able to charm the wife of the French Governor into providing him with a number of forbidden fruits, including coffee seeds from which Brazil has certainly benefitted considerably. Regardless of the details, Wickham’s seeds did arrive at Kew on 14 June 1876 and were planted in seedbeds the day after their arrival. Within a few weeks 2397 of them had germinated (rather less than the 10% or seven thousand subsequently claimed by
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93 Wickham). We know that 1919 of these seedlings were then sent to Ceylon (Sri Lanka) under the charge of one of the Kew gardeners, William Chapman, where there were three days of panic as no one had arranged for the harbour dues to be paid. However, the seedlings were eventually released and 1700 survived to be planted at the Heneratgoda Gardens in Colombo. By 1880 it was reported that only some 300 were still alive. At the same time that the seedlings were dispatched to Sri Lanka, two cases, containing a total of fifty seedlings, were sent to Singapore for the attention of H. J. Murton, who had been placed in charge of the Singapore Botanical Gardens in the previous year. These were offloaded and left in a shed for a month before being collected—dead. As the Kew Report of 1876 succinctly says: In the case of Singapore . . . Owing to the delay on the part of the India Office in paying the freight the case did not come into the hands of the Superintendent of the Botanical Gardens to whom they should have been consigned till the plants were nearly all dead.
In September 1876 a further 100 seedlings were sent to Sri Lanka. These were presumably from ‘Wickham seedling’ cuttings as no new source was known to have come into the UK until the botanist and explorer Robert Cross, whom Markham had sent to the Amazon to provide back-up in case of Wickham’s failure, returned in November of that year with just over 1000 Heveas, as well as some Cearas and Castilloas. Kew gave away just over half of these but retained 400, from which about two dozen survived. We also know that 100 plants went to Sri Lanka in the summer of 1877 and a further 50 to India. In all, by the end of 1877, Kew had distributed over 3000 seedlings; this was vastly more than their primary stock, so there must have been considerable
Tears of the Tree 94 propagation from cuttings. Sri Lanka then forwarded 22 seedlings, probably from that delivery of 100, to Singapore. All of these survived and Sir Henry Ridley, Director of the Singapore Botanical Gardens, was later to remark that it was from these 22 seedlings in the Gardens that more than 75% of the cultivated plants in Malaysia were derived. Unfortunately, in spite of all the detailed records kept by Kew, one piece of information is missing, and that is the certain source of those 100 seedlings. We do not know whether they were propagated from ‘Wickham’ or ‘Cross’ plants. Whilst many writers claim, without giving verifiable references, that they were from ‘Wickham’ plants, we have the firm opinion of Ridley that they appeared different from the original (Wickham) seedlings and that they were from ‘Cross’ plants. He made this claim many times in his career and maintained it to the end. The last paragraph of a letter written by him to W. B. Turrill at Kew in 1950 (see Fig. 6.3) reads: I conclude therefore that the 22 plants which were sent to Singapore from which almost all the cultivated plantations derived are from Cross not Wickham.
Fig. 6.3 The last paragraph of Ridley’s letter of 1950.
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95 This remains yet another great unanswered question in the ‘biography’ of natural rubber. The question was first raised with Kew in 1910 by P. J. S. Cramer of the Botanic Gardens at Buitenzorg, in W. Java, Indonesia, possibly resulting from earlier discussions with Ridley. He was answered by David Prain at Kew, who said that there was no chance that Cross’s seeds could be involved. However, if we look at p. 88 of the Selected papers from the Kew Bulletin. III—Rubber, there is the statement that Robert Cross: . . . arrived at Kew on 21st November 1876. He brought with him about 1080 seedlings without soil, of which, with the greatest care, scarcely 3% could be saved. About 100 plants propagated at Kew from these were subsequently sent to Ceylon.
Another early report—W. Wicherley (one-time Head of Botany at the Rubber Research Institute of Malaysia) writing in The whole art of rubber growing (1911)—repeats the observation, including the dispatch of 100 of the Cross seedlings to Sri Lanka. All of the information from a variety of sources can be tabulated as follows. 14 June 1876 Wickham arrives at Kew with around 70 000 seeds. 12 August–October 1876 Kew sends to Ceylon 1919 Wickham seedlings. August–September 1786 Kew sends to Singapore 50 Wickham seedlings (died in harbour). September–November 1876 Kew sends to Ceylon 100 Wickham seedlings. 21 November 1876 Cross arrives at Kew with 1080 seedlings. Early 1877 Kew sends to Ceylon 100 Cross seedlings. 11 June 1877 Ceylon sends to Singapore 22 Cross or Wickham seedlings?
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Tears of the Tree October 1877 Singapore to Perak: 9 or 10 from these 22 seedlings sent to Malaysia as the basis for most of the plantation industry.
One small ‘fly in the ointment’ remains and this is a letter from H. J. Murton to Kew, dated 6 September 1877: Our climate is evidently suited for the growth of Hevea, judging by the growth the plants you sent last year have made.
This must refer to the first batch of seedlings, sent in late 1876; but, judging by the considerable evidence that all or virtually all of these had died due to maladministration, this could be an attempt by Murton to salvage his position now that he had the second delivery, should anyone come to inspect them. It did him little good as his career came to an abrupt end two years later when he was convicted of embezzlement and sent to prison. In any event, William Anderson (Chairman of the Raffles Library and Museum, Singapore) wrote to the Colonial Secretary on 30 September 1876 saying that Murton had told him that, by the time he had been notified of the seedlings’ arrival, they were all dead. In summary therefore, and contrary to what some authors claim, on p. 88 of the Selected papers from the Kew Bulletin. III— Rubber Dr Trimen clearly states that the 100 seedlings sent from Kew to Sri Lanka in 1877 were Cross seedlings. His comment that Cross’s contribution was small reflected the fact that this 100 should be compared with the 1919 (þ100) Wickham seedlings which had been shipped to Ceylon, but, this comment is not relevant as we are only concerned with the 22 seedlings which were subsequently sent to Singapore. What is still undetermined is whether those 22 seedlings sent from Ceylon to Singapore came from this last batch of seedlings (apparently from Cross if Trimen
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97 and Ridley are to be believed) or were from other (Wickham) stock held there. Whether the truth can ever be established now is doubtful, but perhaps we should consider Cross, not Wickham, to be the ‘father of the rubber plantation industry’. It should be added that a further shipment of Hevea, Castilloa, and Ceara seedlings held at Kew from Cross’s travels were dispatched to Sri Lanka on 15 September 1877, but these were too late to be the source of the famous 22 seedlings. In Sri Lanka experimental plantings were carried out at the Botanic Gardens at Heneratgoda and Peradeniya, the latter being in the highlands near Candy. The planters were not convinced that Hevea was the best option and they also experimented with Ficus elastica, as well as Castilloa and Ceara. Initially, the last two were favoured because of their quick maturation, but were eventually displaced by the slower growing but higher yielding Hevea. By 1882 the young plants were bearing seeds and the further development of government plantations in India was through this route. ‘Private’ demand for the seeds, however, was poor as many planters had been made bankrupt by the coffee blight which had struck a few years earlier, and those who had survived had already replanted with tea or moved to Malaysia to start afresh. Indeed, in 1887 Kew received 2000 seeds from Sri Lanka in the hope that a home could be found for them as they were not wanted there. Soon, however, the situation had changed, and by the 1890s it was reported that some planters were doing so well from their seed sales that they saw no need to go through the daily grind of tapping! In the Botanic Gardens, Dr H. Trimen was active in developing tapping procedures so that he could get an ongoing supply of latex from each tree in such a way that it would produce for an appreciable number of years. His results led him to conclude that
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Fig. 6.4 Henry Wickham with one of the original Heveas at Heneratgoda in 1911.
rubber had a viable future in the country, so he set out to convince both the Government and the private tappers that this was the case. In 1896 he was succeeded by J. C. Willis, who had the added impetus of being able to promote rubber due to the falling prices for tea, and he was also able to obtain considerable government assistance towards a replanting programme. From this a thriving plantation industry developed, although, after an initial very rapid growth, land restrictions precluded the continuing expansion which took place in Malaysia. Figures for acreage under rubber in
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99 Ceylon were: 1900, 1000 acres; 1905, 66 000 acres; 1910, 258 000 acres; and 1920, 433 000 acres. Although many samples of Sri Lankan Hevea rubber were sent to the UK for evaluation, it is generally accepted that 1899 marked the first commercial exportation of plantation rubber from that country. Returning to the Malaysian peninsular, it should not be thought that the arrival of 22 seedlings in Singapore in 1877 created the Malaysian plantation industry overnight. Indeed, officialdom was not particularly interested in the idea as the country had tin, and the mining of this was exceedingly profitable. Murton planted 10 seedlings in the Singapore Botanical Gardens and in October he contacted the Resident—Sir Hugh Low—who expressed an interest in the plants and their potential. Murton then set out with 10 of the seedlings for the Residency at Kuala Kangsar. Nine seedlings were planted in the Residency gardens, where they were nurtured by Hugh Low, whilst the tenth was believed to have been planted in Taiping, although no trace of it was found when Hugh Low looked for it the following year. One of the 9 seedlings still exists as the photograph in Fig. 6.5 shows. Investigations of both Hevea and indigenous rubber-producing plants were carried out by Murton, at the Singapore Botanical Gardens, and by his successor, N. Cantly. In 1885 Cantly claimed that the latter offered better commercial potential. Meanwhile, in 1884 Frank Swettenham, later to be the High Commissioner of the Federated Malay States, planted 400 Hevea seeds from the Kuala Kangsar trees in Perak. More were planted in Selangor between 1883 and 1885 by T. H. Hill, although these were possibly ornamental rather than commercial plantings. In 1888 Henry Ridley, a former gardener at Kew, then aged just thirty-five, was appointed Director of the Singapore Botanical Gardens and suggested that the Government should consider large-scale plantings since there was little private interest in
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(a)
(b)
Fig. 6.5 (a) One of the original Heveas planted at Kuala Kangsar in 1877, and (b) its associated plaque.
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101 planting crops which would take five years or more to start paying their way. He was able to use his additional position as Supervisor of the Straits Forest Department to carry out plantings in both Singapore and in the vicinity of Malacca, and, like Trimen in Sri Lanka, he investigated different ways of cultivating and tapping the trees to optimise the yield. He published his ideas in 1897 and, following these, Curtis in Penang and Derry in Kuala Kangsar obtained yields of latex from which they were able to calculate that rubber production could be profitable. It was also noted from samples sent to England that there would be a ready market for plantation rubber as it was much cleaner and more consistent in quality than the wild rubbers of either Africa or Amazonia. It is perhaps ironic that another Brazilian commodity had pushed Malaysia into rubber, whereas in Sri Lanka it had had the opposite effect. Various government inducements had encouraged planters to create and expand plantations and many of these chose coffee as their main crop. The price of coffee had been high due to production problems in Brazil, but, by the mid-1890s, these problems had been overcome and the fungal disease which had wiped out the Sri Lankan industry was attacking the Malaysian plants. In 1895 Tan Chay Yan planted forty-three acres of Hevea on his estate at Bukit Lintang in Malacca and the Kindersleys planted a further five acres in Selangor. These were the first commercial rubber estates in Malaysia and, as the coffee market collapsed, more and more planters turned to rubber. Initially the plantings were interspersed with cash crops, but by 1898 Stephens, in Perak, was planting dedicated rubber plantations. At about this time Ridley (now universally know as ‘Rubber Ridley’) noted that he had received requests for one million seeds in a single day! Although there was no mechanism for collecting reliable statistics on land usage prior to 1905, some idea of the speed at
Tears of the Tree 102 which the industry developed can be obtained from the following estimated figures for total rubber acreage in all of what is now Malaysia: 1898, 2000 acres; 1900, 6000 acres; 1905, 46 000 acres; 1910, 540 000 acres; and 1920, 2 180 000 acres. By 1920 wild rubber had been essentially consigned to history and plantation rubber had arrived with a vengeance. However, the story of Brazilian rubber does not quite end there. Henry Ford wanted a more controllable source of rubber for his car tyres, so in 1928 he purchased some 25 000 square kilometres of land sixty miles south of Santarem, on which he set out to create not only a plantation but also a complete town for his workers. He named it ‘Fordlandia’. Unfortunately, he encountered numerous difficulties and after five years only about ten (a)
(b)
Fig. 6.6 (a) H. N. Ridley with a Hevea tree showing herringbone tapping. (b) A modern tapping panel. Thin slivers are removed each time the tree is tapped. By tapping progressively the trunk can regenerate and the process can continue.
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103 square kilometres per year were being planted. It was obvious that the venture was never going to succeed, so Ford abandoned the site and in the early 1930s began work at ‘Fordlandia II’ or ‘Belterra’ on a new site much closer to Santarem. Although he imported high-yielding rubber seeds from Asia, labour problems and poor soil conditions, resulting in stunted growth, again doomed the venture, which Ford finally abandoned in the late 1930s, selling out to the Brazilian Government for a pittance in 1945. Then the story ended! Let us now return to Henry Wickham. He and his wife were back in England in June 1876, and in July and August Wickham persisted in trying to persuade the Director of the Botanic Gardens at Kew (Dr Joseph Hooker) to employ him so that he might accompany some of the young rubber seedlings to areas of the tropics then under Britain’s control and complete what he now saw as his mission. Hooker rejected the idea, having no proof of, or faith in, Wickham’s arboricultural expertise. So Wickham took the £700 paid to him for delivering the seeds and set out with his wife for a new life in Queensland, where he intended to grow tobacco and coffee. Life in the Amazon basin had been very difficult for him and it had no intention of getting better! A change in the wind direction caused the fire he had started to clear scrubland to set fire to the thatched cottage which he had built, and the building, with all their possessions, was destroyed. A second dwelling was built— this time with a corrugated-iron roof which was ripped off in a storm. Finally, he was left with massive debts when his partner, for whom he had stood guarantor, walked away from the business. He sold up, cleared the debt, and returned to England. Shortly after his return in November 1886 he was on his way to British Honduras, where he obtained a government post. His wife joined him and, for once, her diaries showed a degree of contentment with their social existence. Wickham, however,
Tears of the Tree 104 longed for life in the wild and started another plantation some sixty miles from ‘civilisation’. On this occasion there were problems with his lease and during his long legal argument over the land rights he petitioned Queen Victoria directly. Having apparently taken advice from King Solomon, she wrote on his solicitor’s statement ‘Let justice be done. Victoria R and I.’ The ‘justice’ finished with Wickham again having to sell up and return to England in poverty in 1893. Next he turned to the sea and took a concession to develop a small group of coral islands to the south-east of Papua New Guinea, the Conflict Group. These islands turned out to be aptly named because, after two years without seeing another white woman, his wife had finally had enough and returned to England, never to see her husband again, although she lived a month longer than he, dying in late 1928. As always, he was hampered by a lack of investment capital and negligible business acumen. Although he had one more try at developing a rubber plantation on New Guinea, he eventually gave up these enterprises and returned to England; his final return being in 1911. Even in England he continued to speak his mind on how rubber trees should be planted, cultivated, and tapped, and he invented various devices such as tapping knives and rubbersmoking machines. As the reader might expect by now, his ideas on rubber cultivation were contrary to the pragmatic ‘best practice’ developed in the Far East, whilst his inventions were commercial failures. In 1911 he at last gained some financial reward from the rubber industry with the gift of a silver salver, a £1000 cheque, and an annuity purchased with a further £1000. In 1920 he was knighted for ‘services in connection with the rubber plantation industry in the Far East’ and in 1926 the American oil magnate Edgar B. Davis presented him with
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105
Fig. 6.7 Sir Henry Wickham, 12 october 1926.
a cheque for £6000 as an 80th birthday present. Soon afterwards the British Government of Malaysia gave him £8000. Two years later he was dead. What then can one make of Sir Henry Wickham? One view was expressed by Henry Ridley, the person who, more than any other, persuaded the country we now know as Malaysia to develop rubber plantations: I looked on him as a failed planter who was lucky in that for merely traveling home with a lot of seeds had received a knighthood and enough money to live comfortably in his old age . . . He ordered natives to bring him in the seeds and to pack them in crates and put them on board ship. One cannot help feeling he was jolly well
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paid for a little job. He was no agriculturalist, he knew nothing about rubber and cared not for it . . . As for his abilities in planting I should say he had none.
Edward Lane, one of the very few people to have studied Wickham’s life in detail, wrote of him in 1953 as an ardent imperialist with little business acumen and with an autocratic manner which made him difficult to get on with, yet he was a staunch and loyal friend to those he really liked. Fordyce Jones, a close friend in Wickham’s later years, called him: a great man . . . whom to know was to love and whom all those in the rubber industry who have its interests at heart have affectionately called its ‘father’.
Although these remarks consider different aspects of the one man and his life, there seems little conflict between them. He was
Fig. 6.8 Tapping Hevea trees on a modern Malaysian plantation.
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107 domineering, egocentric, but a true friend. His business acumen was undoubtedly hopeless, but, at one point in his life, he was ‘in the right place at the right time’. In order to boost his ego and standing, he had to make an adventure out of a simple voyage, and in so doing his exaggerations and deceptions hid beyond recovery the truth of his one successful activity which certainly did change the world for ever (if the 22 seedlings really were from his seeds and not from those of Robert Cross!).
7 The King and the Congo In the early 1880s the article shown in Fig. 7.1 appeared in a British magazine. But the truth was somewhat different. In the previous chapters we have seen that wild natural rubber could be obtained from many plants and that these are widely distributed across the tropics, sub-tropics, and even the temperate regions of the Earth. However, only one region other than Amazonia made a significant contribution to the world’s supply of this material during the late nineteenth and early twentieth centuries, and this was the Congo. The timescale over which the development of this trade occurred closely mirrored that of the Amazon basin but its gestation was very different. The Amazon region had long been noted as the source of natural rubber and production naturally rose in an attempt to meet a growing demand. The methods by which this was brought about will be discussed in the next chapter and, depending on one’s viewpoint, could be ascribed to enthusiastic entrepreneurs or to ‘robber barons’ operating within their own very private fiefdoms. The exploitation of the Congo grew out of one man’s lust for money with which to establish a family dynasty, together with his remarkable ability to convince a broad spectrum of European politicians and businessmen that he was a great humanitarian and that he was acting with pure altruism. That man was Leopold II, King of the Belgians.
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Fig. 7.1 How to get rich in the Congo.
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Tears of the Tree 110 Leopold’s story begins with the foundation of the free and independent state of Belgium on 20 January 1831. Prince Leopold of Saxe-Coberg was eventually chosen as its king and came to the throne later that year. On his death in 1865, his son, the Duke of Brabant, who was just three months younger than the country, became King Leopold II. In accepting the kingship his father had also agreed to be bound by the Constitution which, it was thought, would keep him in his place, but, it contained a fatal flaw. The king was Commander-in-Chief of the army and was therefore in charge of the nation’s defence. This obviously required considerable interaction with his European neighbours and so enabled him to take control of foreign affairs, a useful portfolio to pass to his son. Leopold II seemed not to have had a particularly happy upbringing. He was tall, thin, and, according to many reports, he had an enormous nose. He was also idle (or suffered from late development) but he did develop a passion for the accumulation of data of all description, which he filed, classified, and crossreferenced. His father does not seem to have been particularly fond of him, but in later years acknowledged that he was his own man and that, whilst abrasive and over-sure of himself, he was also showing signs of subtleness and a manipulative ability which would manifest themselves with a vengeance in the not too distant future. Belgium’s problem was that neither the country nor the monarchy was built on ‘old money’. The new country had passed through many crises in its first thirty-four years and was now reasonably rich as well as politically neutral. Leopold II was certainly not rich and this led him to argue that Belgium could not stand still but should strengthen her position by becoming even richer, in the anticipation that some of the wealth might rub off on him. Given his inherited position as director of foreign affairs, it
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111 seemed an obvious move to consider which accessible parts of the world remained unclaimed by existing colonial powers and what riches he could seize therefrom for his country and himself. The first question was where to start. He had already travelled extensively, visiting Egypt in 1855 and again in 1864 en route to China via India and the Malay States. As a result of these travels he had identified three types of colony: the slave, the white e´migre´, and that containing large numbers of indigenous workers under white control. He identified the last as being the most appropriate for his purpose and he noted of Java, where forced labour was used, that it was ‘the only way to civilise and moralise these idle and corrupt populations’. Nevertheless, he appreciated that he would have to be rather more circumspect in presenting his intentions to those whose help he wished to solicit in his endeavours. It was soon brought home to him that neither the prospect of an external source of income nor an appeal to patriotism would galvanise his fellow countrymen into activity. His plans became one stage clearer when he wrote, in 1863, ‘Belgium does not exploit the world, it is a taste we have got to make her learn.’ Over the next ten years Leopold investigated a number of possible countries in which he might have been able to take, or purchase, influence, but none proved acceptable. However, in August 1875 a letter to a confidante contained the sentence, ‘I intend to find out discreetly whether there may not be anything to be done in Africa.’ It took little effort on his behalf to focus down from ‘Africa’ to ‘the Congo’, a virtually blank area on the map which had recently become the subject of renewed interest following the discoveries and writings of Livingstone, Speke, Baker, and Burton into the interrelationship between the Nile, the Lualaba, and the Congo river itself. At first glance it may have seemed an obvious choice to settle some of the arguments by following the Congo inland from
Tears of the Tree 112 the western seaboard and to see where one finished up, but the complex of rapids and cataracts 100 or so miles inland made further navigation impossible. Indeed, it had been tried in 1875 by a German team but their efforts failed after a few days. At the end of that same year Lovatt Cameron turned up on the west coast, near Luanda, after a two and a half year journey through the heart of Africa from the east coast. Some of his comments struck crucial chords with Leopold. Tales of rich mineral deposits, grain, and rubber triggered his financial lust, whilst the stories of the Arab slavers with their heavily laden caravans provided an opportunity for him to appeal to Belgian missionary zeal and, hopefully, gain access to the country through apparently altruistic and honourable means. Two problems remained; the first was how to bring about this move into the Congo without upsetting or alarming the other European nations, and the second was how to extract any valuable ‘assets’ without, at best, having to share them with another country or, at worst, precipitating open hostilities. This was to be resolved at the Brussels Conference of 1876 in a manner which proved how well Leopold had learned to manipulate, lie, and distort facts during his formative years. His father was to be proved right but he would not have approved. The Brussels Conference was a gathering of scientists, explorers, and geographers. They came from Austria, Britain, France, Germany, Italy, and Russia, and they were all famous names. It was completely non-political and Leopold’s proposition was that Central Africa should not be a place of national squabbles and bickerings, but that an international body should be set up which would suppress slavery and develop the country and its infrastructure through normal and fair commercial practices. Exploration would be controlled by the geographers, whilst national sub-committees would be set up through existing learned
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113 bodies which would be financed by national governments but not subject to political control or influence. In his opening speech, on 12 September, Leopold laid out his ‘public’ position: The subject which brings us together today is one of those which must be the supreme preoccupation to all friends of humanity. To open to civilisation the only area of our globe to which it has not yet penetrated . . . a crusade worthy of this century of progress. . . . Many of those who have made the closest study of Africa have come to the conclusion that their common purpose would be well served by a conference to get their work in step, to concert efforts, to share all resources and to avoid covering the same ground twice . . . Need I say that in bringing you to Brussels I was guided by no motives of egoism? Belgium may be a small country but she is happy and contented with her lot. I have no other ambition than to serve her well.
He then set out the following three points to be addressed. 1. Location of bases and whether they are to be acquired by treaty or purchase from the natives. 2. Location of routes to the interior, with the setting up of posts for scientific research, the abolition of slavery, and the education of the natives. 3. Establishment of the central and national committees, and deciding the best way to appeal to each nation’s charitable instincts for finance. The meeting then established the international authority itself, formally known as the ‘Association Internationale pour Reprimer la Traite et Ouvrir l’Afrique Centrale’ but more commonly known as the ‘Association Internationale Africaine’ (or AIA). This was to be managed by an ‘International Committee’ chaired by Leopold on the understanding that the chair would progress annually through
Tears of the Tree 114 different national representatives. There was then established an ‘Executive Committee’ and the various ‘National Committees’. It was a remarkable conference and altruism, coupled with the spirit of pure research, triumphed—for a short time. The International Committee met again in 1877 and, forgetting its own rules, re-elected Leopold to the chair. It never met again. The Executive Committee reported on the AIA’s operations until 1880, whilst, with the exception of that of Belgium, the National Committees never even saw the light of day. Leopold’s intention at that time was somehow to find a way for Belgium to take control of the AIA, but over the next two years it became a political brickbat, with all political parties as well as the Catholic Press putting their selective interpretations on what the AIA was really up to. Fortunately for Leopold, none deduced his real intent of using its ostensible purpose as a front to pacify and confuse the other nations whilst he got his colony up, running, and secure, but it rapidly became obvious to him that Belgium was unfit to receive the polished jewel which he was creating. He would just have to establish his own private colony in the Congo basin. The new question was whom could Leopold trust to set up such a structure? He would have to know something of the African native, believe in himself, be prepared to use force where necessary, and yet, at the same time, at least initially whilst the scheme gathered momentum, be gullible and unappreciative of Leopold’s true intent. Out of the jungle, having taken almost three years to cross Africa from Lake Tanganyika down the Lualaba and the Congo to the West African Coast, came Henry Morton Stanley (see Fig. 7.2). H. M. Stanley is known to the world as the American journalist who issued the immortal greeting ‘Dr Livingstone I presume’ in
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Fig. 7.2 ‘Henry Morton Stanley’.
November 1871 when he located the missing explorer at Ujiji. In fact, he was neither ‘Henry’, nor ‘Morton’, nor ‘Stanley’, nor American, and it is arguable whether his journalism was based more on fact than on fiction. He was born in Wales in 1841, one of several illegitimate children of Betsy Parry, and his birth certificate identifies him, with little subtlety, as ‘John Rowlands— Bastard’, the first of many indignities which contributed to the character which Leopold found so useful. The first six years of his life were spent with his grandfather who did not believe in sparing the rod and, when he died, John was deposited in the St Asaph Union Workhouse. Here he seems to have been the recipient of
Tears of the Tree 116 the worst kinds of Victorian sexual and physical abuse, but gained a passion for geography, an elegant script, and a bible as a prize from a local bishop. At fifteen he left St Asaph’s and for two years lived as the ‘poorhouse boy’ with various relatives before shipping to New Orleans on a split-second impulse. In a series of moves which would be recognised by any psychiatrist today, he then began a process of reinvention, taking on the name of the merchant who befriended him when he landed and inventing a whole new autobiography. There is no doubt that his early childhood left him with what would today be called ‘sexual hang-ups’ and it can be no coincidence that, in years to come, he departed on two of his African journeys soon after becoming engaged. Neither lady waited for him. After a stint in the American Civil War—fighting for the Confederates at the battle of Shiloh and then for the Union Navy bombarding Confederate ports in North Carolina—he started his journalistic career writing freelance articles and then turned to covering the Indian wars for a variety of Eastern papers. The conflict between the papers’ desire for stories of blood and thunder and the fact that the wars were virtually over and that Stanley’s time was spent covering peace missions was easily resolved, as his fictional reports of the Indians on the warpath showed. His reports and style were appreciated by the publisher of the New York Herald, James Gordon Bennett Junior who hired him to cover the British–Abyssinian war. Here, foresight and luck played equal parts in the advancement of Stanley. He had already bribed the telegraph operator in Suez to send his dispatches before all others and, just after his report of a British victory, the telegraph cable out of Suez broke, so no more dispatches could be sent. This scoop, in June of 1868, resulted in his being given a permanent position as a roving reporter on the Herald, but it took
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117 until the end of 1871 for him to become a household name, as famous as the explorer whom he had found. This mattered to Stanley, who never regarded exploration as anything more than the establishment of a factual framework within which he might weave his arguably fictional tales of daring-do and thus obtain the riches he never had as a child. His books were so popular that it would be fair to identify him as the first of a long sequence of professional travel writers, but, once again, he was fortunate. Livingstone died in Africa and did not return to Britain, where his story might well have conflicted with that of Stanley’s as told in How I found Livingstone. Stanley was now thirty years old. Yet again, his past returned to haunt him as the ‘upper crust’ Royal Geographic Society refused to acknowledge his exploring abilities, and rumours about his birth began to spread. This could be professionally damaging to an ‘American’ writing for an antiBritish paper in the US. His insecurity was further increased when he discovered that his fiance´e had married whilst he was away. His answer—to return to Africa—could be considered escapism or a need for more background for his next book. Finance was available from Gordon Bennett, Levy-Lawson of the UK Daily Telegraph, and others for an Anglo-American expedition to solve a number of geographical problems relating to the land west of Lake Tanganyika and, particularly, to establish the relationship between the Rivers Lualaba, Nile, Niger, and Congo. Livingstone had thought that the Lualaba formed the headwaters of the Nile, but Lovatt Cameron believed it fed the Congo. Stanley initially favoured the Niger but slowly came to prefer the Congo. The world wanted to know and he could see money in a book. The expedition set off in 1874 with Stanley, three other whites whose lack of experience suggested that they had been chosen so that they would not detract from Stanley’s glory, and their main means of transport, the Lady Alice, a forty-foot steam launch which
Tears of the Tree 118 divided into five sections for portage. The boat was named after Stanley’s second fiance´e, the seventeen-year-old Alice Pike. The expedition also contained over 300 Africans. Stanley’s attitude to the natives was exactly what Leopold required and can best be illustrated by two examples. Stanley was, of course, equipped with the most up-to-date armaments and was perfectly happy to fight his way past any tribal opposition, particularly when it consisted of bows, arrows, and spears, with the occasional antique muzzle loader. He noted that: ‘we have attacked and destroyed twenty-eight large towns and three or four score villages’. However, when necessary, he was capable of a more subtle approach, illustrated in his conversion of the Emperor of Uganda to Christianity. This was brought about by making him aware of the church’s eleven commandments, the one we would not recognise being that man must ‘honour and respect kings as they are envoys of God’. Starting down the Lualaba, Stanley travelled several hundred miles before the first portage round ‘Stanley Falls’ and then he had a clear run of almost 1000 miles to ‘Stanley Pool’. Lest it be thought that his egotism was running a little high, he named Mount Gordon Bennett, the Gordon Bennett River, the Levy Hills, and Mount Lawson after his main sponsors. The naming of ‘Stanley Pool’ was at the insistence of one of the other whites, Frank Pocock, or so Stanley claimed; but as Mr Pocock, like Stanley’s other two white companions, died on the expedition we can only take his word for that. The final 200 or so miles west of Stanley Pool to the coast were a continuous string of rapids and waterfalls, which made Stanley realise that he was on the River Congo. The boats were abandoned and a desperate four and a half months of marching through the jungle were needed to arrive at Bomba. The epic Through the dark continent, published by Stanley in 1878, tells all from his point of view in his established and popular
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119 style, although one fact which is missing is the number of native survivors. We know that Stanley was the lone survivor of the four whites who set out, and that the death toll amongst the natives was massively high. Perhaps Stanley’s failure to record this detail just reflected his lack of interest in the trivial details of his successful expedition. The only sour note to be sounded was when he discovered that his second fiance´e had preferred the ‘bird in the hand’ and had married an American railway heir a few months after they had separated. He would have been more distressed to know that in later years, after his death, she claimed remorse that she had not waited for him and professed that it was her spirit, together with the physical presence of the Lady Alice, which had motivated and carried him across Africa. Leopold had found his man. In fact, Stanley had first come to Leopold’s attention when his plans to follow the Lualaba downstream had been announced three years earlier. Leopold believed in Lovatt Cameron’s supposition that the Rivers Lualaba and Congo were linked, and he was also aware that in 1874 Lovatt Cameron had annexed the Congo in the name of Queen Victoria—only to have the British Government reject the annexation as soon as it heard of it. Leopold’s immediate problem now was how to recruit Stanley without alerting the British. He therefore resolved to employ Stanley to explore the Congo basin and establish some posts under the auspices of the AIA. A little early discussion with Stanley seemed a good idea, so he sent two emissaries to meet him at Marseilles, where his train had stopped en route to Britain from Italy. Stanley was not interested; he wanted plaudits from his countrymen (the British) and time to write his book. Inevitably, Leopold had to use a small coterie of trusted employees in his machinations, but some consciences were
Tears of the Tree 120 pricking and questions were being asked as to how Stanley could be offered this position without the approval of the Executive Committee of the AIA, and what exactly was the purpose of the posts which he was to establish. The situation would soon become clear to those in the know and more complex to everybody else. By June 1878 Stanley had become tired of the negative attitude of the British Government, which was too tied up in Egypt and the Nile to consider further African undertakings, so he travelled to Brussels for a meeting with Leopold. The two got on well, but Stanley emphasised that the first stage of any useful opening-up of the Congo required a railway round the lower falls and rapids. Funding was a problem, but a proposal from the Dutch traders at the mouth of the Congo for a ‘study syndicate’ fitted nicely into the ostensible purposes of the AIA, and a group of European financiers agreed to support this. The syndicate came into being as the ‘Comite´ d’Etudes du Haut-Congo’. Its terms of reference were never published, but came to light in 1918 and included a clause excluding the Comite´ from taking any political action. Like so many of Leopold’s clauses and contracts, this seems to have faded into oblivion very quickly if one considers the evidence of a document found in the Belgian Foreign Ministry archives. Leopold writing to Stanley: . . . It is a question of creating a new State as big as possible and running it . . . there is no question of granting political power to Negroes . . . the white man will head the stations which will be populated by free and freed Negroes. Every station would regard itself as a little republic . . . The work will be directed by the King [Leopold] who attaches particular importance to the setting up of the stations . . . the best course of action would be to secure concessions of land from the natives for the purposes of roads and cultivation and to found as many stations as possible . . . should we not try to extend the influence of the stations over the neighbouring chiefs and form a Republican Confederation of native
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freedmen. The President [of the Confederation] will hold his powers from the King.
The emphasis on ‘freed men’ fitted in with the aims of the AIA and gave Leopold the time he needed to implement his real schemes, more honestly set out in a private letter to Stanley in August 1878. Stanley was to acquire as much land as possible by purchase or concession on behalf of the Comite´, which would set out the laws of this ‘free state’ with Leopold, as a private citizen, at its head. Although Stanley obtained close to 1 000 000 square miles of the Congo for Leopold, the latter was not happy as the French, through Count Savorgnan de Brazza, established a camp at Stanley Pool, the site of the future Brazzaville. What Stanley did not know was that the Comite´ d’Etudes du Haut-Congo no longer existed! In November 1878 Leopold announced to his shareholders that most of the money used to found it had been spent and the rest was committed to contracts already underway. He felt very sorry about this, but was prepared to return their original investments in full and offer them preference should any commercial undertakings grow from the enterprise. All he asked was that the Comite´ be dissolved. This was agreed and the Comite´ d’Etudes du Haut-Congo was immediately replaced by the Association Internationale du Congo (AIC) with 100% funding from Leopold. This fund provided the treasury of the Congo Free State, which was thus also owned by Leopold. The similarity of the names of the AIA and AIC were hardly coincidental. As Leopold wrote to a supporter, ‘care must be taken not to let it be obvious that the AIA and AIC are different, the public doesn’t grasp this.’ Leopold remained dissatisfied with Stanley’s qualities of leadership and in 1882, when Stanley was in Brussels, they discussed his possible successor. Leopold was interested in recruiting General Gordon, who was avidly anti-slavery and whom he had
Tears of the Tree 122 met earlier; he would be an ideal ‘front’ for the AIC. In 1883 Leopold offered him a position, suggesting that a field marshal’s position in the Congo would be a considerable advance on a generalship in England. Gordon accepted, but changed his mind when the British Government asked him to oversee the pacification of the Sudan and, specifically, to relieve the isolated garrison in Khartoum. He became trapped there and was killed in 1884. History now regards him as a hero and, whilst it may have been a bad career move in the very short term, it is doubtful whether he would have fared so well if he had chosen the Congo route. Although his financial position had now been strengthened, Leopold was still looking for international recognition and started with the United States of America as being the country least likely to understand the complexities of the pyramid of power which he was creating or, indeed, Africa itself. It proved relatively simple to confuse the Americans. In the President’s message to Congress in December 1883 the AIC was referred to as the AIA and the Comite´ d’Etudes du Haut-Congo was taken as a branch of the AIA. By February 1884 both Congress and the Senate recognised the flag of the AIC as that of the Congo Free States (not yet one state). Leopold then staged a magnificent coup by, in one statement, binding France, Germany, and Britain to his scheme. The statement, issued jointly by the AIC and the French Prime Minister, said in essence that the AIC would not cede any of its territory to any power, but that if it ever had to realise its assets then France would have first refusal. The contradiction went unnoticed or, at least, it was not commented on. Now France could relax, knowing it would have no problems with the AIC and could, potentially, have some rich pickings, whilst Germany and Britain now had no option but to support the AIC and so prevent it falling to the French.
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123 Two items remained to be dealt with before Leopold had the kingdom he craved. The first was the Berlin Conference of 1884– 1885, arranged by a number of European powers in an attempt to sort out a range of conflicting land claims in Africa. Interestingly, it was not felt necessary to invite any Africans. Leopold busied himself negotiating numerous bilateral agreements, but had surprisingly little trouble in acquiring the million or so square miles of Central Africa which he sought, as well as the port of Matadi and the land on which to build his railway past the rapids. There were probably two reasons for the ease with which he was granted his claims. The first was that most delegates had never even seen Africa and believed that, for them, any wealth came from trading at the water’s edge. The second was that it was still believed that Leopold’s organisation, be it the AIA or AIC, was generating some sort of international colony which would be one giant freetrade area. It took Leopold just three months to clarify the nomenclature when, by royal decree, his privately purchased country became the ‘E´tat Inde´pendant du Congo’—the Congo Free State. Note that the ‘States’ approved by the US had become one state a one-letter difference which went unnoticed. His second problem was cash flow. His efforts to date had cost him a fortune and he still did not have his railway, which was essential for the transportation of the riches of the Congo from the interior to the coast in reasonable quantity. At this time he was still thinking of ivory, and rubber hardly featured in his calculations. In 1887, for instance, only thirty tons of rubber came out of the Congo. He needed money and turned to his own (first) country, Belgium, which was beginning to realise that there might, after all, be some financial benefits to be had from the Congo. Using a combination of his philanthropic record, the ‘French possession’ threat, and a will in which he left ‘all his sovereign rights’ in the Congo Free State to Belgium upon his death, he received an interest-free loan
Tears of the Tree 124 of £1 000 000 (1890 value). He promised to borrow no more without the prior approval of the Belgian Parliament and to repay the loan (or have the Congo annexed by Belgium) by the end of 1900. The French do not seem to have been consulted and, in a typical gesture of altruism, the king backdated his will by a year to August 1889, thus making it appear that his generosity had nothing to do with the ‘subsequent’ loan. Although the political wheeler-dealing, corruption, and lies continued to the end of Leopold’s reign, he now had his State, but to take full financial advantage of it he needed four fundamental things. He had to put in place posts throughout his new land in which to pace his administrators and their ‘enforcers’, ‘recruit’ a labour force, develop the river transport on the 1000 or so miles between Stanley Falls and the rapids, and build Stanley’s railway from east of the rapids to Matadi. In addition he needed stability. He was aware of the growing demand for rubber and of the competition he was facing from South America and the plantations in the Far East. He was now close to sixty years old and needed to make money fast. His idea for short-to-medium-term stability was simple: he would involve directly, and for their own financial benefit, influential political and commercial friends throughout Europe who would, in the preservation of their own interests, support him against his detractors. He also appreciated the particular advantage to himself that he would then be able to offload any approbation onto their shoulders and off his own! This was achieved by a decree of October 1892 which split the Congo into three zones. The first, the ‘Domaine Prive´e’, was to be solely for his financial benefit and consisted of an area around Lake Leopold II and Lake Tumba. In 1901 it was supposed that it had been set up by a decree of 1896, reserving the land as ‘Crown property’, but this was subsequently shown to have been forged. The Domaine Prive´e was about
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125 ten times the area of Belgium. A second region was to be either sold on to new owners or distributed between concession companies. The largest of these companies, known as the ‘Anversoise’, was to be in the hands of his close friends, but, by 1898, a 50% interest had been acquired by the Congo State (Leopold). The next largest, the Anglo-Belgian India-Rubber Company (ABIR), was notionally under the chairmanship of an Englishman, Colonel North, although it later emerged that his financial stake was purchased with Leopold’s money. As with the Anversoise, Leopold soon owned at least 50% of the shares and the British interest reverted to the Belgian. Perhaps the most interesting area, from the point of view of Leopold’s machinations, was that situated around the River Kasai. This was designated a free-trade area, although Leopold’s organisation already controlled a major part of it and was particularly obstructive when independent traders tried to work within its ‘free’ economy. Within the 1892 decree was the comment, once again overlooked by all, that the free-trade rights would cease when Belgium ‘was in a position to take over the sovereignty of the Congo’. By the terms of the Belgian Government’s loan this was 1901 and, although Belgium did not take up its offer, it was in a position to do so. Leopold took over again, for once with the law on his side, and that was the end of free trade. With his land and position reasonably secure he could concentrate on transport and infrastructure. In 1890 Stanley’s railway was started at Matadi. Three years later it had advanced fourteen miles at a cost in African life which is, even now, unknown. The official figures claimed 1800 non-whites and 132 whites, but less official (and more reliable?) sources suggest that the 1800 figure only relates to the first two years of its construction. Nevertheless, the line was extended to Stanley Pool over the next five years and was then open for business.
Tears of the Tree 126 Three weeks of portage were reduced to two days of steampowered transportation. Leopold needed steamboats above the rapids well before the completion of the railway so that he could use the clear 1000 miles of river, and its tributaries, to put in place his administrative infrastructure. These boats had to be dismantled and carried past the rapids and, as an indication of what this involved, just one of the steamboats required over 3000 ‘porter loads’. With transport now under control Leopold could get his ivory and rubber out—when it had been collected. It has already been observed that his preferred modus operandi would be trading posts with a white man in charge of the native work force. The posts, with their white agents in charge, were put in place, but, since the native workers had to be coerced to do anything for the agents, a middle tier of management was required. This was supplied by soldiers of Leopold’s private army, the ‘Force Publique’, which supplied both garrisons for general area protection and local ‘sentries’. The officers of this army were generally whites, often from Belgium but sometimes from other countries, lent to Leopold to learn the techniques of native control. Other ranks were often enslaved as much as the rubber tappers proved to be. They were generally stationed far from home and were left to be self-supporting. However, possessing guns, they were one off the bottom of the pyramid of power and not actually on the bottom. That position was reserved for the tappers and their families. There were inevitably some mutinies, but, if these could be suppressed and the tappers forced to produce their full allocation of rubber, the soldiers had some chance of survival. Looking to the future, Leopold organised children’s camps, ostensibly under the auspices of the Catholic Church, which were intended to educate the native orphan children, but, in actuality, his purpose was to turn them into trustworthy soldiers.
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127 The orphans tended to be collected from villages destroyed by the Force Publique and, if they were not orphans when they were found, they became so very soon afterwards. The control of gangs of labourers by armed supervisors is nothing new, but, because of the individual work of the natives in collecting the latex, a new protocol had to be developed by the agents and put into operation by the sentries and the Force Publique. The vine which produced most of the Congo rubber was of the landolphia genus, which climbed a convenient tree and then spread out through the upper branches of its neighbours. When one was first located the latex could be extracted by tapping or incising close to the ground, but the tappers then had to move higher and higher up the vine for subsequent tappings. More latex could be obtained by cutting completely though the vine, but this was terminal to the vine and forbidden. If caught doing this, it was also terminal for the tapper! As the vines close to a settlement ran dry the tappers had to move further out, often making journeys of a day or more. The usual trading goods of trinkets and the like were not of sufficient interest to the natives for them to put up with the rigours of a tapper’s life and Leopold had made certain that the Congo was, at least to the natives, a ‘no money’ economy. Money could give you power in that you might purchase guns or other undesirable products. Force was the obvious means of persuasion and this was better used against women and children than against the tapper, who might then be unable to work efficiently. A procedure was soon established and documented in the official manual given to all agents. The soldiers would arrive at a settlement, loot it of animals and any other items of value, destroy the buildings, capture the women and children, and imprison them in stockades built close to each trading post for just this purpose. They would then be ransomed against an arbitrarily decided weight of rubber.
Tears of the Tree 128 On returning with the rubber, the tappers often found that their women had been raped by the ‘sentries’ and/or had died from starvation or some disease. If the natives objected to the forced labour the settlement was wiped out. Since Leopold did not want to waste money, his agents knew exactly how many bullets were issued to each soldier and these were not to be used shooting game for food! The bullet usage was supposed to relate closely to the number of natives killed, and the soldiers supplied evidence of their kills by cutting the right hand from each corpse and smoking it so that it might be preserved for subsequent checking. When one agent suggested that the hands could have come from women, easier to catch and kill, penises were brought in to prove the honesty of the soldiers. Severed heads had been considered trophies of inter-tribal wars long before Leopold took an interest in the Congo, but he certainly had no objections to the continuation of the practice. One agent, Van Kerckhoven, paid his soldiers 1p per head ‘to stiffen their resolve during battle’, whilst another used twenty-one heads to decorate his flowerbeds. This is probably the origin of Marlow’s observation of Kurtz’s collection of heads in Joseph Conrad’s book The heart of darkness. In the ultimate statement of self-justification one agent reported how, when local villagers failed to meet their fish and manioc quota, he decapitated 100 of them: ‘There have been plenty of supplies ever since. My goal was ultimately humanitarian. I killed 100 people but this allowed 500 to live.’ Tales of horror and destruction could continue, but the point has been made and it is time to turn to the fall of Leopold. It has already been noted that he fought a running battle with his critics throughout his ‘Congo mission’, but for many years his outward altruism and humanity, as well as influential friends who
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129 were also gaining from his efforts, protected him. One of the earliest attempts to bring him to some accountability was initiated by a black American soldier, lawyer, and preacher, James Washington Williams. Williams was already known in America as a proponent of black civil rights. In 1889 he wrote to Leopold suggesting that he could recruit black Americans to work in the Congo, where they could advance themselves in a way impossible in the US. He came to Europe, met and was impressed by Leopold, and in 1890 set out for Africa, where he spent six months touring the Congo. He was a civil rights activist and what he saw sickened him. His response was to write an Open letter to His Serene Majesty Leopold II, which was also published as a pamphlet and widely distributed throughout Europe. He wrote a similar letter to the President of the United States of America, President Harrison. In the ‘open letter’ he accused Leopold on eight major points: Stanley used a range of crude conjuring tricks to persuade the natives that he had supernatural powers and to induce them to sign over their tribal lands for trivial recompense. Stanley was not a hero but a cruel foul-mouthed tyrant. Leopold’s African soldiers had to be self-sufficient and the results—death of the unhelpful natives and the destruction of their villages—followed from that. Leopold’s soldiers were excessively cruel to their prisoners. There was no wise government, no schools and no hospitals for the natives. The judicial system was corrupt and unjust. Whites could get away (literally) with murder whilst blacks could receive terrible punishments, including death, for trivial, or even invented, offences. Kidnapping natives to be used as concubines by state officials was commonplace. Leopold’s government was systematically slave trading throughout the Congo.
Tears of the Tree 130 In a letter to America he coined a phrase which, still today, is the ultimate condemnation. He described Leopold’s operations in the Congo as ‘a crime against humanity’. Leopold immediately set out to discredit Williams, a now standard procedure when one cannot contest a person’s argument, and found a number of grounds on which to do so. His most fortunate break occurred when in August 1891 Williams died of tuberculosis aged just forty-one. The rumblings continued, but, without his passion to fan the flames, they slowly subsided. Even that august newspaper, The Times, saw fit to write a leader in 1895 which included: . . . a system of compulsion closely akin to slavery would be necessary before natives of the Congo Free State could be trained to regular voluntary labour.
Another black American missionary, William Henry Sheppard, was in the Congo at the same time as Williams and for partly the same reason—to find a country where black Americans could develop without segregation. Unlike Williams, however, he was based at one place, the Presbyterian mission which he and a colleague had established far up the River Kasai, the home of the Kuba people. This was so remote that it took eight years for Leopold’s soldiers to reach it, and during that time Sheppard established a remarkable rapport with the natives. He appears to have been one of the very few black men respected by both whites and blacks in the Congo at that time. With the arrival of the soldiers the world fell apart, the Kubas resisted with what they had and were massacred as thousands sought shelter in the mission. In 1899 Sheppard was told by his superiors to go into the jungle and find out what was happening. What he found were smoked right hands and the soldiers smoking them, for it was he who first publicised the practice in missionary
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131 magazines throughout both Europe and the States. His, and other missionaries’, articles continued to infuriate Leopold, who in 1906 made it an offence punishable by a fine or imprisonment to commit any calumny against a Congo State official. After the first conviction of a Baptist minister, things quietened down a little, but in 1908 Sheppard published the story of another Kuba revolt and the way in which it was put down. The local concessionaires, the ‘Compagnie du Kasai’, demanded a retraction and, when Sheppard’s colleague pointed out to the company that they had a lot more charges to make, the Compagnie became more enraged. Whilst the arguments were continuing, the British Vice Consul visited the region with Sheppard as guide to prepare his own report. When this was published supporting Sheppard’s story, the company had had enough and sued Sheppard for libel. The judge reserved judgment as he worked out what to do. The Americans had made it clear that their attitude to Belgium’s claim on the Congo could depend on the result, whilst the judge’s career was obviously finished if he found for Sheppard. The verdict was clear. Since Sheppard had not named the Compagnie du Kasai in his article, it could be assumed that he was only blaming soldiers of chartered trading companies for the massacres and did not intend to make an attack on the defendant; Sheppard was innocent and the Compagnie not guilty. Although the story of Sheppard has been told in isolation, it forms only part of the greater story concerning the downfall of Leopold. If Leopold was the schemer and Stanley the realiser then E. D. Morel was their nemesis. Edmund Dene Morel was the son of an English widow who had been married to a Frenchman. At the age of seventeen he moved from Paris to Liverpool to become a clerk in the Elder–Dempster shipping line. He had no history of political activism; neither did he know, nor care, much about Africa. The shipping line had plied
Tears of the Tree 132 the routes to Africa for a number of years and held the contract for all cargo to and from Leopold’s Congo. Being bilingual he soon became the liaison officer between the line and the Congo officials in Belgium, and regularly visited Antwerp to compile and check the records of goods received and dispatched. It did not take him long to realise that a great fraud was being perpetrated—and that even worse things were happening. The fraud was obvious to someone used to dealing with figures. Leopold’s various trading companies and the Congo Government published certain trade figures for exports, whilst the amounts of ivory and rubber unloaded at Antwerp greatly exceeded them. Millions of pounds were floating loose somewhere. The more disconcerting discovery was that there were regular shipments of guns and ammunition out of Antwerp into the Congo, assigned to either the State itself or to various named trading companies. Coupled to this was the fact that over 80% of the goods being shipped to the Congo were of no benefit to the natives, but were intended to prop up the administrative system. How then were the ever-increasing quantities of ivory and rubber being paid for? He knew that money was not an option as the natives were not allowed to use it, and yet Elder–Dempster had a monopoly on all trade. The only answer must be that they were not being paid. They were, in fact, slave labour. At the end of the century, in his mid-twenties, Morel found his conscience and, blistering with outrage, set out to destroy Leopold and his operation in the Congo. He first revealed his suspicions to Sir Alfred Jones, head of the shipping line and also Honorary Consul in Liverpool to the Congo. Howerver, since Jones was more concerned with keeping his lucrative contract than on displaying moral principles, he was reluctant to stir the muddy waters. He did, however, promptly visit Leopold, who told him, in essence, that the natives had to be subdued for their
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133 own long-term benefit and it would be better if this young clerk learned some discretion—quickly. The offer of a pay rise and a transfer away from the ‘Congo desk’ was rejected, only to be followed by a more blatant bribe which was again refused. In his younger days Morel had written some freelance articles for trade journals and found he had some flair for the written word so, in 1901, aged twenty-eight, he resigned and started his onslaught. Unfortunately, there were limits to what he could get published, so, two years later, he started his own paper, The West African Mail, in which he had total editorial control. Contrary to the philosophy of most newspapers, a good story to Morel was one of unimpeachable veracity and, whilst always writing with all the fury he could muster, he was infallibly accurate in everything he wrote. Every attempt by Leopold’s supporters to catch him out was foiled. On complaining that the story of natives being forced to work through the kidnapping of their women was false, Morel was ready with a copy of the form given by the ABIR to all its agents headed ‘Natives under bodily detention’ and an order on the upkeep and feeding of hostages. As Morel’s fame spread he received letters, reports, and copies of documents from a vast number of people, including employees of Leopold in the Congo and clerks in the Belgian offices of Congo companies. Missionaries, who had at last found a mainstream publisher outside the normal run of religious pamphlets and journals, willingly released their pent-up emotions and produced more irrefutable evidence—photographs. Of the eyewitness stories which Morel published, just one sums up Leopold’s Congo. It came from an American agent working for the ‘Anversoise’, Edward Canisius: . . . We had undergone six weeks of painful marching and had killed over 900 natives, men, women and children. The incentive? Adding fully twenty tons of rubber to the monthly crop.
Tears of the Tree 134 One of Morel’s supporters was Sir Charles Dilkes MP and in 1903 the Congo question was raised in the Houses of Parliament. A resolution was passed making clear Parliament’s belief in Morel’s writings and protesting over the treatment of the natives. It also expressed concern about Leopold’s failure to live up to his free-trade promises. Leopold became concerned and so started a campaign to present his side of the story: Britain was intent on destabilising his operations because British gin manufacturers wanted to export their product to innocent natives but his enlightened administration would stop them. Missionaries were bigots out to force their beliefs on everyone by any methods. The very profits he was making from the Congo showed how well the natives were being treated.
Would this be enough and had he bought enough politicians and businessmen for things to quieten down yet again? The answer was soon forthcoming; the Foreign Office sent a telegram to HM Consul in the Congo and asked him to investigate. The Consul was the thirty-nine-year-old Roger Casement, who had been in Africa for much of the last twenty years and had seen it all. Amongst other activities, he had worked for the surveyors on the ‘rapids railway’ and had spent a week with Stanley in the Congo. In 1890 he had shared rooms with a Polish ship’s officer, Jo´zef Konrad Korzeniowski, who was on his way to learn the secrets of the river so that he might take control of his own steamer. Six months was all he could take in the Congo and later, as Joseph Conrad, he wrote of the atrocities he had witnessed in The heart of darkness, a work of fiction embedded in fact. In 1892 Casement worked in what is today Nigeria and then transferred to the British Consular Service. In 1900 he was to set up the Consular Service in the Congo. He was fully aware of Leopold’s activities in the Congo and had already written to the Foreign
The King and the Congo
135 Office about them. Now he had permission to investigate officially and he was not to let either the natives or his government down. For over three months he travelled throughout the Congo and the more he learned the more sickened he became. He returned to Britain to write his report and, although it was written in the formal restrained way of a government document, the factual and graphic contents were much more than the Government expected or, perhaps, wanted. It was Casement, for instance, who dispassionately described the severing of penises in confirmation that the corpses which had provided right hands were males. Pressure to stop publication came from highly placed sources, including the British pro-Leopold Minister to Brussels, who wanted to ‘avoid being put in an awkward position at the (Belgian) court’, and the head of the Elder–Dempster shipping line, for more obvious financial reasons. The report had to be published, particularly since the frustrated Casement had given several interviews about its contents to the press, but, as a compromise, all names were purged. Casement seethed when Leopold’s apologists issued general denials which he was unable to defend with specifics. It appeared that the ‘sentries’ were to protect the tappers (from what or whom?) and those unfortunates with missing hands had had them amputated to prevent the spread of cancer of the hands. Luckily for Casement’s sanity, he had, by then, met Morel, whose work he had read whilst in the Congo, and the two men struck up an immediate strong friendship. Out of this meeting came, in 1904, the ‘Congo Reform Association’, the intention of which was to persuade European governments to take action against the abuses of human rights in the Congo. He knew that politicians prefer a quiet life whenever possible, so he sought out support from a wide range of lords, MPs, churchmen, and businessmen, and kept up a continuous barrage of public (and private) meetings and writings. Perhaps his most famous book is
Tears of the Tree 136 Red rubber: The story of the rubber trade flourishing on the Congo in the year of grace 1906 in which, in a central section of thirty-six pages, he documented close to 100 reports which he had received, from a broad spectrum of sources, concerning atrocities committed on the Congolese natives between 1890 and 1905. Each report was accompanied by a full provenance. As some indication of his prolific outpourings, it is estimated that he wrote over 3500 letters in the first half of that year (1906) alone. Leopold now realised that neither his words alone, nor those of his apologists, were enough to stop the rising tide of concern and resentment being orchestrated from Britain. He was presented with further problems when American missionaries lobbied President Roosevelt, claiming that, as the US was the first country to recognise the Congo Free State, it had a special responsibility to protect its indigenous population. Forced to act, predominantly in response to the Casement report, Leopold set up an ‘International Commission of Enquiry’ consisting of three judges, one from each of Belgium, Italy, and Switzerland, who were to travel to the Congo to investigate Casement’s allegations. They returned to Belgium in March 1905, but Leopold kept their report suppressed until November of that year. In the meantime a Belgian Member of Parliament struck gold. He asked a provocative question: ‘Were bonuses still being paid to agents in inverse proportion to the value of the goods they exchanged for rubber and ivory?’ The Foreign Minister explicitly denied any such policy, only to have read out to him the confidential State documents confirming that this was official policy. The finally released report of the Commission of Enquiry was a shattering blow to the Belgian Government. It listed the following. 1. The land laws: contrary to the Berlin Directive and would militate against the development of native life.
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2. 3. 4. 5.
137 Forced labour: applied with unpardonable ferocity and reprisals. Bonus system: unacceptable and dishonest. Powers to concession companies: intolerable. Legal system: biased and inadequate.
(Shades of Williams’ ‘open letter’ over a decade earlier.) Leopold’s choices were becoming very limited and became more so in March 1906 when a motion to revive the Annexation Bill of 1901 was passed in the Belgian Parliament. Leopold realised that he was beaten in terms of actual ‘ownership’ of the Congo, but he still had more than half a pack of cards to play in concealing the multiplicity of companies in which he had shares, or owned outright. He was content to hand over the administrative shell if he could keep the contents. He retreated to his yacht, the Alberta, and his Villa des Ce`dres on Cap Ferat, and prepared his defences. These would require their own chapter to detail, but they consisted of a series of defensive ‘walls’, built on the assumption that, as each defence fell, another would be there to back it up. In mid-1907 the Congolese and Belgians agreed to produce a draft treaty and negotiators were appointed, several of whom happened to be friends of Leopold. By the end of the year a draft treaty had been produced and signed which proved that Leopold had succeeded with his most important defence wall—the Belgian State pledged itself to recognise the Foundations existing in the Congo. This would include Leopold’s ‘Fondation de la Couronne’, formed as a ‘Fondation’ barely a year earlier but holding Leopold’s ‘Domaine de la Couronne’ (that tract of land ten times the area of Belgium) as its major asset, together with a massive portfolio of land holdings throughout Belgium and southern France, shares, and cash. The Government could not
Tears of the Tree 138 accept this and was surprised when Leopold gave way in early 1908. It had not appreciated the purpose of his ‘walls’ and by now he had finished putting most of his fortune out of reach of the Government. However, he still believed that he had a saleable asset. There was, and still is, no argument that a large amount of Leopold’s wealth went into building works throughout Belgium, and the Government agreed to take these over and complete them as well as taking responsibility for their many outstanding debts. Leopold himself kept the ‘goods and movable assets’ of the ‘Fondation’ and received a gift of £2 000 000 in recognition of a nation’s gratitude. The politicians still argued but the end was in sight. A speech from the throne by King Edward VII in 1908 represented the ultimate approval of the work of Morel and his colleagues. The King hoped that negotiations between Belgium and the Congo State would result in a State humanely administered in the spirit of the Berlin Act. The Belgian Parliament had to act if it was to retain any credence and self-respect, so the treaty became law in 1908. On 8 November 1908 the flag of the Congo Free State was lowered for the last time, but it took several more years for the Belgian Government to dismantle the ‘Leopold legacy’. It was 1913, the year in which the Congo Reform Association disbanded, that Britain recognised that the transfer of power was effective. By then Leopold had been dead for three and a half years, finally succumbing to an intestinal operation on 14 December 1909. Was it worth it and what was the cost? No one knows the answer to either question. Some figures have been produced, most comprehensively in terms of rubber production, by Morel, who, after his discoveries in the late 1890s which precipitated Leopold’s fall from grace, set out to establish realistic figures for
The King and the Congo
139 Congo rubber exports. The best one can say is that they represent minimum figures. From the earliest days of trading through the west coast settlements, small amounts of rubber had become available for export at the instigation of the traders. Unlike his Mesoamerican counterpart, the African native had little use for the material except as an adhesive to fasten spearheads and arrowheads to their shafts. By 1888 it was still a small amount, representing about 10% in value of all exports, rising to 25% by 1895, 50% in 1896, 70% in 1898, 85% in 1900, and peaking at 90% in 1901, but remaining in this area for the rest of Leopold’s ownership of the Congo. It has been estimated that, between 1898 and 1905, raw materials to the value of about £14 000 000 were exported from the Congo for the benefit of Leopold and his collaborators, whilst imports, mainly to support the ‘administrative’ regime, were some £6 000 000. In tonnage these figures represent an output of between 4500 to 6000 tons each year from 1900 to 1908. It was also estimated that Leopold’s ‘Domaine de la Couronne’ gave him a clear profit of some £3 000 000 between 1896 and 1906, whilst the State’s rubber exports in its peak year of 1901 were estimated to be some £2 000 000. These estimates were calculated on the ‘most realistic estimates’ of exports from a mass of data and not just on the ‘official’ documents of the time which first aroused Morel’s suspicions. They also exclude his profits from companies in which he had shares, usually over 50%. Morel estimated his income from dividends alone in the three major companies to be £360 000 in 1904–1905. In attempting to ridicule the figure of £3 000 000, the Belgian Premier, a known apologist for Leopold, produced figures to show that it was at least a factor of four too large. Unfortunately, his mathematical errors
Tears of the Tree 140 did not escape the Members of the Belgian Parliament, who felt that even the £3 000 000 was an underestimate. In calculating Leopold’s financial gains from the Congo, the various loans he raised between 1888 and 1904 should not be forgotten. The Belgian Premier suggested £3 000 000, whilst others, less in Leopold’s pocket, calculated over £5 000 000. By the time of Leopold’s death the money was rolling in nicely, and it has already been noted that the Belgian Government did not act with an excess of zeal to stop the slave trade when it took control at the end of 1909. The money was, after all, useful to balance the country’s books and complete Leopold’s lavish projects. In the four following years, 1909–1912, 14 000 tons of rubber were exported, but then came the Great War followed by plantation rubber. The rush for wild rubber was over. After Leopold’s death it took some years for the true size of his residual wealth to surface. Indeed, the complexity of his affairs makes it possible that there could still be a fortune or two, unclaimed and unidentified, gathering interest in bank accounts throughout Europe. Although his private will indicated a wealth of some £750 000, it did not take much sleuthing to discover ‘The Foundation of Niederfulbach’, established in Germany, which contained £4 000 000 in property and bonds which should have been handed over to the Belgian Government with the Congo. After a prolonged legal battle it was returned to the Belgians in 1913. The human cost of the Congo rubber saga is as difficult to calculate as the financial throughput, but it was certainly high. There is general agreement that the population of the Congo in the 1880s was around 25 000 000. In 1911 the official figure was put at 8 500 000, 7 700 000 in 1923, and 8 000 000–10 000 000 in the mid-1930s. Making due allowance for inaccuracies in the 1880s figure, there seems to be no reason to doubt that
The King and the Congo
141 10 000 000–15 000 000 natives ‘vanished’ in the Congo during Leopold’s rubber-grabbing years. Not all of this can be laid at the door of rubber or, indeed, at the door of Leopold himself, for during this period Africa was swept by a devastating plague of sleeping sickness. Villages vanished, as illustrated in a letter from a missionary to Casement who claimed that the population of Lukolela fell from 6000 to 352 in twelve years. Secret flight was an option, but this was against the concession company’s ‘law’ and it was not easy, as the death toll incurred by native porters during many explorations have shown. The birth rate of native Congolese fell substantially in the first decade of the nineteenth century, and this is generally ascribed to the falling numbers of young indigenous males, murdered for failing to meet their target quotas of rubber. However, the concurrent rape of the female hostages should have compensated for this, so the reasons must be more complex. One still has to ask whether this should be factored into any calculations regarding lives ‘lost’ during this period. The rubber tappers had to work between twenty and twentyfive days each month to pay their rubber taxes, and this left them with little time to clear land, build shacks, and grow food. Whichever came first, exhaustion or illness, and either would almost inevitably lead to the other, the result would be a drop in rubber collection and death. If half the missing millions died due to rubber-related causes, the figure would be close to the total population of Belgium and not dissimilar to the total number of dead in the Great War. If we take a not-unrealistic weight of rubber to come out of the Congo as 75 000 tons (75 000 000 kg) and the loss of native life as 7 500 000 then we have the value of a Congolese native life— 10 kg of rubber!
Tears of the Tree 142 Leopold did not know what riches were to be found in the Congo, although he appreciated that ivory was one. His sole ambition was to take control of some foreign land and strip it of its wealth by any means. The fact that the land was the Congo basin, that its major source of that wealth was rubber, and that its extraction cost millions of lives, was irrelevant.
8 Slaves to Rubber At the turn of the twentieth century the rubber plantation industry in Asia was getting off to a slow and shaky start (Ridley claimed that disruptive actions by Sir Frank Swettenham, the first Resident-General of the Federated Malay States, had set it back by at least ten years), whilst the African rubber industry was extremely small. Nevertheless, the industrialised countries, particularly America and Great Britain, were crying out for rubber and had to rely on the Amazonian basin to meet their demands. Statistics prior to about 1835 are difficult to find, but at that time the rubber exports from Para´ were as likely to be unvulcanised rubber overshoes as the raw material. The weight of the latter was less than one ton per week. A letter from Mr James Upton to Mr Seth Low of New York in March 1831 details how there are aboard the schooner Betsy & Eliza, en route to New York, one cask and five barrels of rubber totalling 537 lbs net weight which are to be sold ‘for the most you can obtain. I think the quality is very good’. In 1844–1845 the overshoe export market was over 400 000 pairs. By 1849–1850 it had fallen to just over 300 000, and by 1854–1855 it was too small to show in the statistics. The graph shown in Fig. 8.1 was prepared close to one hundred years ago and shows rubber (including the shoes) exported
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144 7000 6000 5000 4000 3000 2000 1000 1836
1846
1856
1866
Fig. 8.1 Graph of rubber exports from Para´, 1836–1872.
through Para´ between 1836 and 1872; in the years 1872 it can be seen that there were about 8000 tons per year. By 1890 that figure had almost trebled to 20 000 tons and the demand was set to escalate to such an extent that these early years would not feature on world production plots through the twentieth century. This is clearly illustrated in the graph showing natural and synthetic rubber production throughout the twentieth century in Fig. 9.1. The obvious event which triggered this demand was the invention of the internal combustion engine, which took place at the same time that Wickham was bringing his seeds from South America and which led, in 1885, to the first motor car proper, manufactured by Daimler and Benz. In 1888 John Boyd Dunlop ‘reinvented’ the pneumatic tyre. The original pneumatic tyre had been patented by R. W. Thompson as early as 1845, but there was no interest in it—probably because the roads were inadequate and it seemed to offer no particular advantage over the solid ones. The Dunlop tyres had a particular shortcoming as they were stuck to
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145 the wheel and thus access to the inner rubber tube in the common event of a puncture was tedious, but by the end of 1890 C. K. Welsh had patented the design of a wheel rim and outer cover with an inextensible lip. The fundamental design feature common to virtually all types of wheeled vehicles had arrived and would only be refined to the present day. The first motor vehicle specifically designed to use a pneumatic tyre took part in the Paris–Bordeaux–Paris race of 1895. Seven hundred and twenty miles (and twenty-two inner tubes) later the Daimler finished ninth in a field of forty-two. The ways in which rubber was ripped from the Amazon basin to meet this demand is the subject of this chapter. Like that of the Congo, it is not a pretty story! The development of the South American and Congo rubber production industries has one common thread—the deaths of millions of natives to meet the demand for rubber in the developing world between the first growth in its demand and the coming ‘on-stream’ of the plantations in the Far East. In other ways they differ. In the Congo the discovery of rubber was pure serendipity for Leopold II, but in South America the story was one of a substance which had been known about in the West for four hundred years suddenly being in ever-increasing demand. Rubber had initially been collected by individual tappers, but towards the end of the nineteenth century this changed to small cooperatives, often financed by trading companies. However, as soon as it was appreciated that vast amounts of money could be made, large companies run by the great, often murderous, ‘rubber barons’ moved in and took over, expanding their empires up the numerous tributaries and feeder rivers of the Amazon by (occasionally) buying out those in their way or (more often) by taking their trees and native workers by force.
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146 COLOMBIA
RI
Atlantic ocean
a can
RC
aqu
eta
R Putumayo
ali cay
OBIDOS MANAUS
RU
s
s
uru
RP
ajo
i
avar
RY
a
ier
ad
M
reg ori
o
R
500 miles
BRAZIL
RG
Madiera–Mamore railway
PERU R Beni
ga lla ua LIMA
PARA BOIM SANTAREM ap
IQUITOS on
RH
Pacific ocean
gro
R Amazon
R Maran
YURIMAGUAS RIOJA TARAPOTO
R Ne
R Japura
RT
ECUADOR
*
uru a
R Napo
RJ
QUITO
R Mamore
*
Marks the disputed border between Peru/Ecuador and Colombia Marks EI Encanto on the upper reaches of the Putumayo
Fig. 8.2 Sketch map of Brazil, Colombia, Peru, and Ecuador showing the rubber rivers and towns.
Manoel Carioca controlled much of the rubber coming down the Grego´rio River—it would take a steamboat seven days to sail through his domain—whilst Luis de Silva Gomes had an estate on the Puru´s River which was estimated to be ten million acres in size. J. G. Arau´jo had half a million acres on the Negro. His expansion only stopped when he came up against another baron as powerful as himself, Germino Garrido y Otero, the ‘King of the Ic¸ana’ to the north-west of the Negro. Perhaps the biggest and most powerful of them all was Nicola´s Sua´rez, who ‘owned’ sixteen million acres around the most southerly of the great rubber rivers, the Beni. These barons, and dozens more like them, did not spend long periods of time in their jungle fiefdoms. The rubber gathering was overseen by their hand-picked enforcers, often criminals fleeing justice, who were usually paid on a commission-only basis, whilst their masters lived and worked in the more congenial atmosphere of the rapidly expanding cities, of which Manaus, located close to the confluence of the Amazon, Negro, and Puru´s Rivers, was the most important (see Fig. 8.3).
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147
Fig. 8.3 Rubber dealing in Manaus in the early twentieth century.
As with any group of people, the rubber barons were vastly different in character once the lust for money and the lack of morality in its making were discounted. The biggest spender was undoubtedly Waldemar Scholz, whose bacchanalian parties included ‘ladies’ bathing in iced champagne from which the male guests would replenish their glasses, whilst, at the other extreme, Arau´jo was a teetotaller and non-smoker whose preferred home was his office and who was responsible for the design and construction of much of Manaus. In many instances the detailed stories of these rubber barons and the ways in which they ran their great estates can only be guessed at. One example which was eventually brought to the notice of the consuming countries through the influence of the British Parliament was dubbed the ‘Putumayo affair’, and knowledge of
Tears of the Tree 148 the atrocities committed therein only came under public scrutiny in the UK because of two miscalculations by its overlord. The Putumayo is a major river in its own right, over one thousand miles long, which rises in the mountains on the west coast of Colombia and joins the Amazon in Brazil. It initially forms the border between Ecuador and Colombia and then, for much of its length, between Peru and Colombia. If it had risen a few miles further to the west it would have emptied quickly into the Pacific Ocean, these events might never have happened, and the story of the South American rubber boom might never have been fully told. It was in this region, in an area about the size of Belgium, that one Julio Ce´sar Arana built his rubber empire. Arana was born around 1864 in the Peruvian town of Rioja, where his father sold hats. His next-door neighbour was a girl a little younger than he, called Eleonora Zumaeta, on whom he was fixated and whom, he knew, he would never win as a shopkeeper. By the time he was fourteen he had left school and was established in his father’s business. In 1879 his father sent him to work as a secretary, where he learned business administration and bookkeeping, but by 1881 he had set out to discover the world beyond Rioja and hopefully to make his name and fortune—and win Eleonora. He set off down the Maran˜on River and then followed the Amazon to Iquitos, Manaus, and finally Para´, where he discovered the important rubber traders. They all appeared to have money to burn—sometimes literally, as displays of ostentation such as lighting one’s cigar with a large denomination banknote would result in one’s neighbour immediately doing the same, but with a note of even more value. Selling hats to a gathering of such exhibitionists, where each would vie to pay the most, was child’s play! In 1884 Arana returned to Yurimaguas, a settlement near Rioja where Eleonora, now a qualified teacher, had opened the State’s
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149 first school, to follow up his fevered written declarations of love with a personal approach, and by 1887 he had won her. During his travels he had become infected by the bites of many insects and animals, but the one he could not shake off was that of the rubber bug, and by 1889 he had established a rubbercollecting business with his brother-in-law, Pablo Zumaeta, in the small settlement of Tarapoto on the Huallaga River, which feeds into the Maran˜on from the Peruvian Andes. Travelling the waterways, he put his business training to good account as he would trade anything for rubber and he always costed the rubber at the price prevailing at the time of the deal. This was usually out of date because of the rising market, but the traders, who may have seen no white man since his last visit, remained in ignorance of that. He then shipped to the US or Europe and sold in the markets there, where the prices were almost inevitably higher. This led to a massive profit on each shipment. But this was not enough. He wanted to cut out the ‘middle men’, so he bought his own rubber estate near Yurimaguas and recruited natives from Ceara´, on the eastern seaboard of Brazil, to work them. These natives were much stronger than the local Indians and could not escape as they were bound by debts to Arana for transport and basic supplies. These debts would never be cleared since they had to buy their supplies in his store at exorbitant prices. In any event, the punishment on recapture for trying to escape tended to be a painful death! By 1896 Arana had moved the centre of his operations downstream to Iquitos and was living in a ten-room house. He had built up international business connections and for eight years he prospered, although still not making the fortune he felt was his right. He believed his operation was too small, so he sold up and went looking for something bigger. Now luck and international politics came to his aid. In 1899 he had first explored the
Tears of the Tree 150 Putumayo River and had traded goods for the rubber collected by a few small isolated trail masters. None of the big rubber barons had found this river and, even if they had, they might not have wanted it as it was a war zone, with the governments of Colombia and Peru continually fighting over its possession. After years of argument they asked Pope Pius X to arbitrate and, at his suggestion, agreed that they would both declare a ‘demilitarised zone’ along the river. Arana moved and bought out nearly, but not quite, all the trail masters to control twelve thousand square miles of Putumayo territory. He was now frustratingly near realising his ambition of having the Putumayo known as ‘his’ river. All he had to do was to remove the few Colombians who were still tapping independently upstream and legitimise his claim to the land. The President of Peru was happy with the arrangement (Arana was of course Peruvian), but Arana needed more funds to cement his control of the region and decided that these could best be obtained by taking the company he had formed with his brother, Lizardo, Pablo Zumaeta, and Abel Alarco—J. C. Arana & Hermanos Company—public. The two largest rubber-consuming countries were the US and the UK, but the UK had one particular advantage; American ships did not journey up the Amazon beyond Para´, but the British operated a regular service between Liverpool and Manaus, and even sent smaller ships further upstream as far as Iquitos, past the junction of the Putumayo and Amazon Rivers. Britain it would have to be. Arana set to work on his prospectus whilst tightening his hold on the river. Although there was plenty of indigenous native labour to be had, they did not have leadership qualities and, like Leopold, Arana realised that supervisors who were in no way related to the workers could generally obtain the highest productivity as there were no tribal or personal loyalties to interfere with their loyalties to him.
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151 His idea was to put in place a strong administrative layer of management, leave his brother-in-law to look after the day-to-day running of the business, and retire to Europe where he had already established his wife and children in a more congenial climate. He soon recruited his supervisors, including two hundred West Indians who were offered two-year contracts, and built up an armed ‘police force’ which had absolute control of all passage up and down the river. Arana had intended the recruitment of the West Indians to be an advantage in floating his company in the UK, but, as we shall see, it backfired with a vengeance. The illustrations in Fig. 8.4 show the public face of the rubber-collecting industry. The people are obviously not from the native tribes which traditionally supplied tappers to the large estates, whilst the ‘Seringueiros’ seem relatively prosperous and well equipped and are more likely to be ‘enforcers’ or family members of the landowners. Throughout 1907 Arana laboured to set up his company, and by early 1908 the Peruvian Amazon Rubber Company was formed, capitalised at one million pounds and with seven hundred thousand £1 shares held by Arana and his family. Important British figureheads on the Board were Henry Read, manager of the London Bank of Mexico and South America, John Gubbins, a merchant with years of experience dealing with Peru (but knowing nothing of the rubber trade), and the mandatory titled director, Sir John Lister-Kaye, Bart. Unfortunately for Arana, the price of rubber was now falling and he was advised to postpone going public for a few months. He used this time constructively to rename the company the Peruvian Amazon Company (PAC) (no ‘Rubber’) and to stress in the prospectus that its main assets were its trading businesses in Manaus and Iquitos. Land holdings around the Putumayo were a minor bonus!
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152 (a)
(b)
Fig. 8.4 The public face of rubber tapping: (a) Amazonian Seringueiros, and (b) tappers smoking rubber pelles.
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153 Just as Arana’s dream was coming to fulfilment, his nemesis was crossing the Peruvian Andes from the Pacific coast and discovering himself at the westernmost limit of the Putumayo. Nemesis here was named Walter Ernest Hardenburg, a twentyone-year-old engineer, born in Illinois, who had been working on a new railroad in Colombia, but who had always had a passion for the Amazon. For over a year he had heard nothing but stories of that river and its riches, so, when he discovered that a railroad was being built alongside the Madiera River, close to one thousand miles south of Manaus, which would bypass over two hundred miles of rapids-infested river to link up with the Mamore´ River and provide an easy route to deliver the Bolivian rubber of Sua´rez to the Amazon, he quit his job with the intention of travelling down the Amazon and up the Madiera to find work there. No one had told him that life expectancy for a worker on the construction site was three months! As he canoed down the Putumayo with a friend and colleague he met various Colombian rubber collectors who treated him well but warned of trouble ahead from Peruvian rubber men, who were slowly taking over the whole river. They claimed that Julio Ce´sar Arana was their leader and that his company was British! Keen to be on his way, Hardenburg put the remarks down to inter-country rivalry and left Remolino with a native Huitoto guide, who told him of the atrocities carried out by the Bolivian overseers—floggings, rape of the wives or daughters, and execution, usually after the amputation of some part of the anatomy and a period of agony—if one did not bring in one’s quota of rubber. One story was very reminiscent of the Congo, where here an overseer would blindfold young girls and use them for rifle practice as they ran about in front of his house. As yet these tales made little impact as the guide admitted that he had seen nothing of them himself but that every forest Indian knew of them.
Tears of the Tree 154 He added that his bosses, the Colombians, were good people and it was only the Peruvians who were bad. As Hardenburg travelled further down the river he began to have second thoughts, as he met people such as David Serrano, who had had his stock of rubber forcibly taken by Peruvian ‘soldiers’ employed by Arana and whose wife had been raped in front of him by the officer in charge, one of Arana’s ‘enforcers’, Miguel Loayza. It was not long afterwards that Hardenburg was taken prisoner on Arana’s ‘flagship’—the somewhat ironically named Liberal—and he heard first-hand of the massacre which had just taken place upstream, including the killing of his most recent befriender, Serrano. As a prisoner of Loayza at El Encanto, he saw for himself how the natives were treated, the tappers being starved, beaten, and left to die if they no longer had the strength to work. He saw young Indian girls working as domestic slaves during the day and either locked in a compound or used as sex slaves at night. Using various official-looking documents which he was carrying and realising Loayza’s lack of English, he was able to bluff Loayza into releasing him and sending him to Iquitos on the Liberal. It was five weeks since Hardenburg had started his journey down the Putumayo and his first priority was to alert Arana to the atrocities being carried out in his name, as he could not believe that the atrocities were being carried out with his prior knowledge. Unfortunately, Arana was away, so, being completely out of funds, Hardenburg took a part-time job teaching English. He stayed with an American dentist, Guy King, who seemed to be aware of the stories about Arana and his ‘enforcers’ but preferred to turn a blind eye to them. Although Acting Consul, he did not see how it could be America’s problem. One day Hardenburg heard sounds of a commotion across the road and saw the police raiding the offices of a local newspaper run by Benjamin Saldan˜a
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155 Rocca, who, he was soon to discover, had tried to rouse the populous by publishing stories given to him by ex-employees of Arana. Hardenburg tried to obtain some of the publications, but to no avail. At last Arana returned to Iquitos and granted Hardenburg an audience, but from Hardenburg’s point of view it was unsatisfactory. Arana told him that he had only visited the Putumayo region a few times in his life and that his soldiers were there to protect his interests against marauding Colombians. Arana added that he would soon be visiting the region again and there the discussion ended. Soon after this meeting he was approached by a young native who claimed to be the son of Rocca, who by that time had fled to Lima in fear of his life, and the native had all of Rocca’s original testimonials from the enslaved natives of the Putumayo. As Hardenburg read them he realised that all he had heard, and more, was true and that Arana was knowingly running his ‘empire’ along lines which, if he had known it, exactly paralleled those in the Congo. Even the tales of mutilation, rape, and decapitation were interchangeable. From that point on, in his writings on the subject Hardenburg referred to Arana’s company as the ‘civilising company’ (his italics)! However, few of the documents were notarised, so Hardenburg set out to find any ex-employees or slaves of Arana who would talk to him directly and whom, he hoped, he would be able to persuade to provide sworn affidavits. Here he was initially unlucky but, as his reputation as ‘a man who was about to do something’ spread, he managed to meet a number of witnesses who would talk freely to him and this gave him the answer to his one big question— why would the overseers act so cruelly; surely they could not all be that sadistic? It was a simple answer: they were only paid commission. At last, with eighteen sworn depositions, he decided it was time to let the British people know what a British company was up
Tears of the Tree 156 to in the jungles of South America. He set sail for London in July 1909 with his mass of documentary evidence that Britain, the world leaders in anti-slavery legislation in the nineteeth century, was home to a company still practising all the most terrible of activities associated with slavery in the new twentieth century. He had first thought of approaching the British directors of the PAC, but then he decided that it would be safer to get his story published. Unfortunately, no paper would touch him for fear of a libel action and, as his frustrations grew, he was only persuaded to continue by his new-found friend, Mary Feeney. Almost at the end of his patience, he was introduced to the Revered John H. Harris of the Anti-slavery and Aborigines Protection Society who had just finished his decade-long campaign against Leopold and the Congo rubber trade. Harris in turn introduced Hardenburg to Sydney Paternoster of the newspaper Truth, who was able to confirm enough of Rocca’s story to begin the crusade in his paper. His allegations included rape, torture, and murder of the natives, and emphasised that the PAC was a British company. The uproar the articles caused could not be ignored by the Government, but it was unsure how to tackle the problem. Then Arana’s second mistake came to light (his first was to make the company a British one). He had recruited British subjects (West Indians) and, if these were being treated as slaves or held against their wishes, then Britain had every right to intervene. The matter was now out of the hands of Hardenburg who, by March 1910, had arrived in Canada to start a new life with his wife, Mary (ne´e Feeney). In May of that year the Foreign Office asked Roger Casement, who, as we have seen in the previous chapter, had been involved in exposing the Congo horrors, to investigate. He travelled throughout the Putumayo region and reported that the fundamentals of Rocca’s and Hardenburg’s allegations were based on
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157 fact. He demanded that the law should take its course and, in order to prevent a Government cover-up, as he had experienced with his reports from the Congo, he copied his report to the Antislavery and Aborigines Protection Society. (This was probably sensible as it took until 1912 for the UK Government to actually publish it.) One year after he had set out, in May 1911, each director of the PAC received a personal copy of Casement’s report from the Foreign Office and it was confirmed in the House of Commons that the allegations were true. Just as they finished reading the report the directors got another shock when Arana’s brother-in-law, Pablo Zumaeta, notified them that, acting with his sister’s (Eleonora’s) power of attorney, he had mortgaged the Putumayo estates for sixty thousand pounds to pay off the company’s debts to her—debts the directors did not realise existed due to their imperfect understanding of the company books! A few months later, in the autumn of 1911, the company was wound up with, amazingly, Arana elected as liquidator to resolve the position as best he could. At this stage it should be pointed out that other voices were being raised against Arana. The governments of Colombia, Ecuador, and Peru were all concerned with the tales coming out of the Putumayo, but nationalism and politics were used by each to manipulate the truth to its own advantage. Colombia and Ecuador used the stories to take the moral high ground and to reinforce their territorial claims on the area, whilst Arana roused all patriotic Peruvians to help him, blaming soldiers from the other two countries for the atrocities. As Arana was Peruvian, the Peruvian Government was in an embarrassing position, although it had been quietly investigating Arana’s activities for some time. Finally, spurred on by articles in the ‘serious’ press, it directed Judge Carlos Valca´cel to investigate. This appointment
Tears of the Tree 158 fell through and it was left to Judge Ro´mulo Paredos to set off and initiate Peru’s formal investigation in early 1911. Four months later he returned with his evidence which, when documented, came to 1242 pages and confirmed all that had been said about the horrors of the Putumayo. Valca´cel supported Paredos and issued over 200 arrest warrants, but the pro-Arana camp was so powerful and vociferous that he quickly realised that his life was in danger and fled the country. The courts cancelled the warrants. Arana’s argument was simplistic and appealing. The PAC was a strong and civilising force in the wilds of the jungle and he was promoting Peru’s national interests and international position; to say otherwise was simply unpatriotic. Within the country this argument could appeal to a compliant Government, but Peru was now facing a rising tide of anger in the UK and, perhaps more importantly, by 1912 the quantity of clean Asian plantation rubber coming onto the market was virtually equivalent to the less-clean wild material, and this was starting to threaten the world market for Amazonian rubber. The writing was on the wall for the whole Amazonian economy. America was sitting on the fence for fear of upsetting its South American neighbours, whilst Brazil was keeping a very low profile as it was well aware that the ‘Putumayo affair’ was not unique but fairly typical of rubber collecting throughout the Amazon and related river basins. The eventual publication of (now Sir Roger) Casement’s report in 1912 by the UK Government contained figures which could no longer be ignored. Casement calculated that at least 30 000 natives had been directly murdered or killed by deliberate starvation brought about by crop destruction for a gain of 4000 tons of rubber in the Putumayo region alone in the first twelve years of the century.
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159 On 5 November 1912 UK Government agents arrived at the PAC’s offices to impound all the company records, and the next day a parliamentary committee began its investigations into the affair. Charles Roberts MP was in the chair. Casement produced both documentary evidence, and photographs, of the atrocities he had seen (see Fig. 8.5). He then delivered to the badly shaken committee a range of trade goods, listing their real values and the prices charged to the tappers by Arana’s company enforcers or trail bosses. It was then the turn of the PAC. First to be called was the company accountant, Henry Gielgud, who had been sent to South America by his employer, a London firm of accountants, to reorganise the books of the PAC. On his return he was asked to report on the treatment of the natives and had assured the directors that they were well treated and happy, but before the committee his answers were rather less
Fig. 8.5 The not-so-public face of the rubber industry: an Indian woman condemned to death by starvation on the upper Putumayo.
Tears of the Tree 160 forthcoming. He prevaricated and blustered, claimed that as an accountant it was not his responsibility to investigate the workers’ conditions, and that his very trip had been devised and orchestrated to provide cover for the PAC. One question which he was unable to answer in his role as accountant was why the company should spend seven thousand pounds on rifles, each costing just over two pounds according to Casement. His suggestion that the tappers might buy them to protect themselves against jaguars was treated with derision since Casement had also pointed out that it would have taken a tapper’s total income for two years to buy one (remember the ‘public face’ illustration in Fig. 8.4). The committee then moved on to the directors and began with the ex-chairman, John Gubbins. Although he had had a career in South America, it had been in the sugar trade in Peru and he, like all the British directors, had never visited the Putumayo. He excused himself from knowledge of the atrocities by claiming that he had read nothing of the background of the company before accepting his directorship and had read nothing about anything to do with its business since. In one outburst in his defence he claimed that the subjection of Indians by commercial companies was the condition prevailing in the whole of the Amazon valley. This did his claim of ignorance little good. He finally admitted that he did accept the evidence and there had obviously been atrocities but, not only was the British board unaware of them, so was Arana, and he would come before the committee and say so. It was doubtful if Arana, at that time at home in Manaus, expected any such outburst from Gubbins, but he was left with no choice if he was to salvage anything out of his rapidly crumbling empire. In the meantime the situation continued to deteriorate for Arana. The mandatory titled figurehead on the board, Sir John Lister-Kaye, confessed to speaking no Spanish whilst agreeing that all board meetings were held in that language. The banker, Henry
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161 Read, was just as ignorant of life in the Putumayo as anyone. He could speak Spanish but claimed that vast numbers of documents and letters were never tabled at board meetings, being dealt with privately by Arana, and that he relied on Arana to provide any information he wanted. He was, after all, a banker looking after his bank’s interests and knew nothing about rubber. Finally, in March 1913 Arana arrived back in England—just in time to hear his company being wound up and to find that he had been stripped of his position as liquidator. Possibly he was able to read Hardenburg’s book—The Putumayo, the Devil’s paradise— which not only told his story but included seventy-three pages abstracted from Casement’s report, and which was published in December 1912. Arana’s defence was three-pronged: nobody had told him what was going on, he had not witnessed anything himself, and his accusers were all of bad character and unreliable. He had to accept Casement’s evidence but, as he had already said, he knew nothing of the atrocities himself. He was then questioned about Hardenburg’s documents and reports. He had already, even before Hardenburg left Para´, set in train a sequence of events which would enable him to call Hardenburg a liar and forger, but this had backfired and he was now called to explain what had happened in detail and under oath. Eventually, he drew back and withdrew all his direct allegations against Hardenburg, yet refused to unambiguously clear him. At that point Hardenburg himself was called. Arana had no idea he was even in the country and sat still as he told his story. Again Arana tried to destroy him by labelling him a forger, but the committee had seen enough to ignore this and returned to press Arana further, who was now claiming that all who had given evidence or testimonies against him were liars and blackmailers who had turned against him because he would not give in to their
Tears of the Tree 162 demands. In the end the committee accepted all the evidence against Arana, including his attempts to destroy the reputations of Hardenburg and others whom he saw as potential troublemakers. The committee’s report showed its opinion of Arana, accusing him of ‘callous indifference and guilty knowledge’, whilst it accused the board members of ‘negligent ignorance’ and ‘deserving of severe censure’. It further concluded that the Putumayo affair was only one shockingly bad instance of conditions liable to be found over a wide area of South America. However, the British courts were unable to try Arana for any specific crime, so he returned to Peru where he continued his rubber business. Britain tried to persuade Peru, Brazil, and the US to close him down, but to no avail. The run-up to the First World War was generating a sustained demand for all the world’s rubber, including whatever could be obtained from the Amazon, and the PAC survived until 1920. In 1921 Arana was granted rights to land along the Putumayo and Caqueta´ Rivers by the Peruvian Government, but a later treaty defined the Putumayo as the border between Peru and Colombia and cost Arana 60% of his holding—for which he received two million pounds sterling in compensation! In 1932 Arana, together with his son and daughter, were involved with a ‘patriotic junta’ which attempted to reclaim what he saw as his land, and this precipitated a full-scale but brief war between the two countries, stopped under pressure from the US. The losers were, as always, the Indians and, this time, Arana himself who finally lost the lands he was fighting to regain. The time had come to retire. He was, after all, now sixty-nine, but it was some twenty years before the end of Julio Ce´sar Arana. He died in 1952. Compared with King Leopold and the Congo, Arana’s reign of terror was on a very small scale but, pro rata, it is comparable.
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Fig. 8.6 J. C. Arana in 1925 as senator from Loreto.
For over a decade he stripped what rubber he could from the Putumayo and the scale of his atrocities can be deduced from the fact that the contribution of the Putumayo to the world’s rubber supply over this period was some 4000 tons—and, according to Sir Roger Casement, the lives of at least 30 000 Indians, that is, four million kilos of rubber for about two million kilos of natives. The British Parliament concluded that this was only one shockingly bad instance of what was probably happening over much of the rubber-producing area of South America!
9 Competition! Although this book tells the story of natural rubber, it would be unrealistic to say nothing of the birth and rise of some of the synthetic materials which have properties broadly similar to those of the natural material, i.e. materials which are ‘elastomeric’. Indeed, these synthetic elastomers are essential to the world in which we live today. So what do we mean by saying something is ‘elastic’ or that it has ‘elastic properties’ (i.e. it is an elastomer)? The basic criterion which all readers will recognise is that it must be capable of undergoing large extensions or deformations and that these must be essentially reversible. For example, a rubber ball will bounce as it returns to its spherical shape from the deformed one it adopts as it hits a surface, whilst a simple elastic band can be stretched up to ten or more times its original length and then revert to its original size when the stretching force is removed. Elastomers have some unusual physical properties and these exclude them from the normal definition of a solid. In fact, the reversible deformability is more reminiscent of a gas and the term ‘elastic’was first used by Robert Boyle in the middle of the seventeenth century to describe the properties of a gas. Charles Marie de la Condamine used the French equivalent, ‘elasticite´’, one hundred years later when he was describing the dried sap he had found in South America.
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165 The facts relating to the reversible deformation of elastomers have therefore been known since the earliest days of Western interest in natural rubber, but the whys remained a mystery. Some of the anomalous properties of an elastomer are known to all schoolchildren, although they may just be accepted without an appreciation of their unusualness. If an elastic band is stretched and quickly placed on the upper lip, an area of extreme sensitivity to temperature changes, it will feel warm or even hot. If it is held stretched until it cools and then allowed to relax then, it will feel cool. A related experiment will prove that, if the band is subjected to some light force so that it is stretched and it is then warmed, it will shrink rather than stretch further as might be intuitively thought. This observation was first noted by Gough in 1805 and investigated further by Joule in the 1850s, when it became known as the Gough–Joule effect. However, it was to be almost 100 years later before the spatial structure of natural rubber was determined and a satisfactory explanation proposed. This is no place to detail the thermodynamics and mathematics of rubber elasticity, but a simple explanation is offered. In 1920 Staudinger proposed the idea that elastomers consisted of long chains of linked smaller units; in 1925 Katz discovered that crystal structure could be seen with X-rays, and in the early 1930s Meyer, von Susich, and Valco recognised that elastomer chains had a statistically random spatial configuration and that they would also have a random thermal motion. By 1932 Busse had documented the conditions required for ‘rubber-like elasticity’. The chemistry of vulcanisation will be discussed later, but, if we imagine the polymer chain as a chain of individual links with some ‘springiness’ in each link, it can be considered here as the tying together of occasional links of different chains, where they happen to overlap, to give a three-dimensional network. Within this the chains are in constant thermal motion (Brownian motion) during
Tears of the Tree 166 which they are able to twist and flex within the strictures of the network. The anomalous effects can now be explained. As the rubber band is stretched the chains become more orientated and closer together, so there is less opportunity for movement. They must therefore lose energy and this is dissipated as heat. On releasing the tension the chains have more space to move in and absorb heat to provide more thermal energy. The band will therefore become cold. Using a similar argument it will be seen that, if a stretched rubber band is heated, more thermal energy will be available and so the chains will undergo more thermal movement. Because the chain lengths between crosslinks are fixed, this will bring the fixed points (the crosslink sites) closer together, and thus the overall stretched length will decrease. Now we know what an elastomer is, we can look at how and why the synthetic rubber industry developed to compete with the natural material. The graphs in Fig. 9.1 show the development of natural and synthetic rubber production throughout the twentieth century and indicate that today around 60% of the world’s elastomers are synthetic. Two features are of particular historical interest. The first is the scale on the left of the main graph, which should be compared with that of the graph of the export of Para´ rubber during the nineteenth century in Fig. 8.1. Plotted on the same scale, Fig. 8.1 would run from 0 to 7 and be totally invisible. The second is the ‘blip’ between 1940–1945 due to the loss of plantation rubber from the Far East during the Second World War. Natural rubber output continued to grow at a steady pace throughout the twentieth century, but demand far outstripped supply and this enabled the synthetic materials to find a market. Of the wide range of materials we shall consider in this chapter there are two, butadiene rubber (BR) and styrene butadiene
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16 000 120
Thousands of tons
10 000
Natural %
12 000
80 60 40 20
8000 6000 4000
Total
100
14 000
Synthetics
0 1880 1900 1920 1940 1960 1980 2000 Year
Natural
2000 0 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91 94 97 Year
Fig. 9.1 Graph of natural and synthetic rubber production 1900–1997, and natural rubber production as a percentage of the total elastomers produced worldwide.
rubber (SBR), which are general-purpose rubbers which can replace the natural material in many applications, although the last still has certain properties which make it the material of choice in certain circumstances. One area in which all of these three elastomers show poor properties is resistance to swelling in hydrocarbon oils, and here two other synthetics come into their own, polychloroprene (CR) and nitrile rubbers (NBR). The growth of the synthetic rubber industry begs the primary question: If rubber had not existed would man have invented it? He certainly would not have set out to because, without its being there, the concept that a material could have been made with such peculiar properties would have been unlikely to have occurred to him. Some elastic materials would probably have come to light by serendipity, since chemists have always enjoyed mixing chemicals together to see what results, but it is doubtful if, without the spur that such a material did exist, this would have occurred until well
Tears of the Tree 168 into the twentieth century. What a difference that would have made! It will also be seen later in this chapter that the vast majority of the modern synthetic plastics industry developed as an offshoot of man’s attempts to make elastic materials. The story of natural rubber is one which developed over a period of time and if one were to highlight some specific people who were responsible for the great steps forward one might think of la Condamine/Fresneau, Goodyear/Hancock, and Wickham/ Ridley. The story of the synthetics is somewhat different as it was first necessary to establish some chemical understanding of the natural material before leaping into the great unknown. Unfortunately for the non-scientific reader, this requires some chemistry. It was obvious to all Victorian scientists that man could improve on nature, and as early as 1860 Williams thermally decomposed rubber and identified ‘spirit’, ‘oil’, and ‘tar’—the spirit, or volatile substance, he named ‘isoprene’ and correctly gave its elemental composition as C5H8. In 1879 Bouchardat recombined isoprene to a rubbery material and Tilden wrote in 1884 of its possible industrial significance (if it could be synthesised cheaply enough—one of life’s perpetual problems for any chemist!). In 1900 Kondakoff polymerised 2,3-dimethylbutadiene to obtain ‘methyl rubber’ and this became the first commercial rubber when it was produced by Bayer in 1909. Interestingly, Tilden had carried out this reaction some twenty years earlier, but possibly by accident or mistake as he never recorded it and his material was only identified recently. In 1912 a few car tyres were made of this elastomer and one set went to Kaiser Wilhelm II. At least one of these is still in existence and was displayed at an exhibition of the history of rubber which toured Europe during 1995–1996. It had oxidised to such an extent that its tread surface was rock hard!
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169 However, it was still not a commercially viable material so Germany obtained most of its natural rubber from the US. This obviously ended when the States entered the Great War in 1916 and German production of methyl rubber was recommenced with some 2500 tons being manufactured by the war’s end. Russia was also active during this period, polymerising many monomers including 1,4-butadiene in 1910 to give butadiene rubber (BR). However, neither the Russian nor the American synthetic rubber industries were under the same pressures as Germany and, with the price of natural rubber low, there was little incentive for anything other than academic research. Although the words ‘polymerise’ and ‘polymerising’ have been used earlier in the chapter, the scientists who had carried out these reactions had no chemical understanding of what they had achieved, and it was only in 1920 that the German chemist, Hermann Staudinger, suggested that they had made molecules of very high molecular weight by chemically combining thousands of repeat units of simple molecules or monomers. He called these long chains ‘polymers’ and later the word ‘elastomer’ was adopted to identify those specifically with elastic properties and so differentiate them from the non-elastic polymers—plastics. The situation regarding research changed drastically in 1922 when the Stephenson Reduction Plan was introduced. This was designed to cut production from the British-controlled plantations and so force up the low price of natural rubber. Over the next three years there was a tenfold price rise—followed by an equally rapid and catastrophic fall as producers outside the control of Britain flooded the market. It was this political intervention in the free market which triggered the next phase in the development of the synthetics. One of the first of the new materials was far removed from the work of the preceding years in that it was prepared, by accident,
Tears of the Tree 170 by Dr Joseph Patrick whilst he was trying to develop a new antifreeze for cars in the early 1920s (although he did not patent the discovery until 1932). Could this be the serendipity mentioned earlier? The substance was an ethylene polysulphide— the first of the ‘Thiokols’ which are still in use as sealants today. Working independently in Switzerland, Baer produced a similar material in 1926 on which IG Farbenindustrie based its ‘Perdurens’, whilst in the States the thiokol rubbers were referred to as GR-P (GR denotes government rubber). It was in 1926 that Waldo Semon synthesised a substance known worldwide today by just three letters—‘PVC’. In actual fact, this is not an elastomer and had been synthesised towards the end of the nineteenth century, but Semon discovered that it could absorb large amounts of certain liquids and the resulting material had, to some degree, elastic properties. Because of this, his later discoveries, and his fascinating life, he merits a special place in the history of synthetic elastomers. Waldo Lonsbury Semon was born in 1898 into a family which had seen its share of American history. His father was an engineer, involved in construction projects throughout the country, whilst two of his uncles had been involved in building the Great Northern Railroad. His grandfather fought both in the American Civil War and against the Sioux with General Custer, whilst his father, Semon’s great-grandfather, had crossed the country from east to west at the time of the Californian gold rush. In contrast, the maternal side of his family had a literary bent and Waldo’s genes seemed to represent a perfect fusion of these two sides of his family. His father travelled extensively, working on numerous engineering projects (Waldo claimed that he had ‘itchy feet’), which resulted in him living in a different place for almost each year of his school life. However, he was fascinated by books and
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171 learned to read and write before he entered school in 1904. His early reading seemed to be shared between his father’s engineering textbooks and his mother’s Shakespeare! His fascination with applied science soon led to experimentation. He built a battery and electric buzzer at the age of nine, and then tried to recharge dead batteries from the live rail of the local electric railway. Surprisingly, and to our advantage, he survived. Fortunately, this failed to dampen his investigative spirit and soon he and two friends cast their own cannons, which they charged with black powder to fire wooden missiles. To show that chemistry was also an interest at that early age, he attempted to dye his aunt’s (white) cat black with silver nitrate. The resulting red, black, and white tricoloured cat was, perhaps, his first intimation that practical and theoretical chemistry often follow divergent paths! His first part-time job, aged eleven, did not suggest a career in science. It was with Bill Cody’s Wild West Show, where his pay was being taught to shoot by Buffalo Bill himself. His next summer job was with an electrical company. Not surprisingly, electricity and radio transmission became his new passion. Moving to Ashland, he set up his first laboratory above the stables of the new family home, but his father was soon on the move again to Oregon where, here at least, he achieved two consecutive years of education before being uprooted yet again. In spite of all these travels, his avid reading and experimentation gave him an academic knowledge well in advance of most of his classmates, but, now eighteen years old, he still had no career in mind. Enlightenment came when the National Bureau of Standards refused him a research position because he had no degree. Mr Miller (a co-founder of Boeing) offered him an immediate position, but pointed out that, ultimately, paper qualifications mattered and he should get himself some.
Tears of the Tree 172 He decided to enrol at the University of Washington where a degree in engineering should have been his obvious choice, but, perhaps because of his father’s wandering lifestyle and a reluctance to continue this for the rest of his life, he chose chemistry as his main subject. Unfortunately, his family was soon off again, so he had to organise accommodation and the means to pay for it. This he did by working evenings and Sundays as a janitor in the University. It was during his first term at university that he met Marjorie Gunn, who was also studying chemistry and would, eventually, become his wife. Perhaps because of his upbringing, Semon had always been interested in the appliance of knowledge to practical problems and this led him to switch from pure chemistry to chemical engineering, where he was soon recognised by his peers as a brilliant experimentalist. By now it was 1918 and the US army took him from his studies, quickly realised his abilities, and set him to work at the University on army projects. Developing a new manufacturing process for TNT must have taken him straight back to his childhood! He finally graduated in 1920 and he and Marjorie were married in September of that year. He then began working for a postgraduate degree, funded by some teaching, whilst his wife tutored students at the University. At the end of this first year, when the colleges closed, their combined incomes fell to zero. Semon obtained a job in a factory which generated gas from oil and coke but which wanted to switch to using local coal. By the end of the summer he had succeeded, but the cost of the plant conversion proved too high for the process to be viable. On the ‘plus’ side, the University heard of his success and offered him a position as Assistant Chemistry Instructor. He was now reasonably settled, with a number of research projects and a plot of land near Seattle where
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173 he was building a house. More stability was provided by the birth of two daughters, Mary and Marjorie, in 1922 and 1924. A third, Constance Anne, was to follow in 1929. However, good fortune did not last, and in 1925 funding changes at the University put an end to his external contracts and forced him to look for a more lucrative position. At about that time B. F. Goodrich of Akron, Ohio, a company known worldwide for its rubber products and, in particular, automotive tyres, was starting to think of developing a synthetic rubber to replace the natural material sourced from the far side of the world. The man in charge of chemical research at Goodrich was Dr Trumbull, who had been Semon’s Professor of Chemistry in his first year at university, and, remembering the abilities of his young student, he offered him the job of inventing this material. Semon accepted and decided to drive to Akron with his family rather than go by train. His interest in developing an improved automotive tyre grew rapidly as he experienced fourteen punctures over the two-week journey! His first project was to synthesise a material which could replace natural rubber as a tank-lining material and which could be stuck to the metal tank (or tubes) with Goodrich’s existing rubber-to-metal adhesive (Vulcalok). He studied what little was known about synthetic polymers and decided to investigate the field of vinyl polymers. These were not new but, as understood, were commercially valueless. The year was 1926 and within a few months he had made polyvinyl chloride (PVC)—a hard white powder which, as already said, Semon found would swell to a gel which was mouldable and had certain rubber-like properties, its hardness and ‘rubberiness’ depending on the amount of solvent present. Unfortunately, he could not bond it to metal—which had been the purpose of the research—but Goodrich got some early return
Tears of the Tree 174 for its investment by way of PVC shoe heels and coated chemical racks. This was not sufficient to provide the company with the funds it needed to keep on developing the material, and it was on the point of backing out when Semon came up with the idea of coating fabrics to give waterproof materials and of producing soft flexible PVC sheets for applications such as shower curtains. The company Vice-President whom he had to convince was a keen camper who was used to being soaked inside his so-called ‘waterproof tent’. Not surprisingly, Semon was able to get his approval and in 1931 a range of products came to the market. The name ‘Koroseal’ was proposed for PVC by Goodrich’s Director of Research and soon became the registered trademark. Semon was granted the US Patent for PVC in 1933, No. 1929453. In speeding through his life, much has been omitted, so it should be said here that this was actually Semon’s 22nd US Patent, the others including amine antioxidants, the adhesive ‘Plasticon’ based on scrap rubber, as well as bookbinding using adhesives instead of stitching and chewing gum. With the success of PVC behind him, Semon returned to his search for a synthetic elastomer to replace natural rubber in automotive tyres. The rise of Hitler and the possibility of the US being isolated from its sources of the natural material concentrated Semon’s, Goodrich’s, and the US Government’s minds, individually and collectively. He was aware of the joint work of IG (which now included Bayer) and Standard Oil in the US into synthetic elastomers, and this was resumed in 1925 as the price of natural rubber soared in response to the Stephenson Plan. They soon managed to synthesise polybutadiene rubber, which was called ‘Buna’, as well as two copolymers synthesised by mixing two different monomers together before the polymerisation stage—‘Buna S’ (styrene butadiene rubber, SBR or GR-S in America) and ‘Buna N’ (butadiene acrylonitrile rubber,
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175 NBR or GR-A). These had reached laboratory production by 1930 but were not industrially developed when reaction to the Stephenson Plan made the price of natural rubber head for the floor again. Semon decided that the polymerisation of butadiene offered the most likely route to a viable synthetic elastomer, but the practical difficulties in obtaining a high polymer were formidable, and it was only in 1939 with solution polymerisation, rather than gas-phase polymerisation, that he got the breakthrough he needed to synthesise a useful material. This, blended with natural rubber, was quickly used to manufacture some automotive tyres and surpassed all expectations with practically determined life expectancies of over 50 000 miles. Goodrich christened his polybutadiene ‘Ameripol’, whilst the tyres, launched in June 1940, were named ‘Liberty Tyres’. Whether this referred to a freedom from Eastern sources of natural rubber or was prescient of their importance over the next five years is not reported. Throughout this period all the work in the US was privately funded and when the Second World War started there were only minimal synthesising facilities. Production only rose from 2000 tons in 1939 to 10 000 tons in 1941. In that year Goodrich agreed to make available its confidential process to its competitors so that the US could increase output in anticipation of its contribution to the anti-Nazi war effort. Semon was appointed Chairman of the Technical Committee which had been set up to coordinate the synthesis of Ameripol and the manufacture of tyres from it, whilst the Government paid for the plant to be built. In today’s money this investment would have been around 3 billion pounds. The first of these came on-stream in mid-1942 and by 1945 the year’s production exceeded 830 000 tons. Over this same early period Germany’s production went from 22 000 tons to a peak of about 100 000 tons in the middle years of the war, and
Tears of the Tree 176 then, not surprisingly, fell to zero in 1945. Directly out of this extended research came commercially viable GR-S or SBR (styrene butadiene rubber), and these two synthetic elastomers remain today the general-purpose rubbers of choice to replace or blend with the natural material. There was one further valuable material to come out of the prewar IG/Standard agreement and that was butyl rubber (IIR). Its precursor was synthesised by IG as polyisobutylene (IM) and had no olefinic groups, so it could not be vulcanised. Standard added a few per cent of butadiene or isoprene to give a low level of residual unsaturation and thus a vulcanisable elastomer—butyl rubber. In 1943 Semon was made Director of Pioneering Research at Goodrich, but he could not get away from PVC which was now being used to manufacture many dozens, if not hundreds, of products ranging from hosepipes to electric plugs and plastic toys of every description. The age of tinplate was at an end. PVC resin was marketed under the trade name ‘Geon’, although it was known worldwide just as ‘vinyl’. In 1993 that part of Goodrich concerned with PVC was spun off as the independent Geon Corporation, and in 2000 Geon merged with M. A. Hannah Co. to form the PolyOne Corp. Waldo Semon continued to work for Goodrich until his Sixty-fifth birthday in 1963, when he ‘retired’ and took a teaching post at Kent State University but by 1971 his eyesight was failing rapidly and he had to resign. Even then he was in considerable demand as a consultant and expert witness, whilst, in his spare time, he worked his vegetable garden. In his eighties he was still teaching informally at local schools, where he believed in the ‘catch them young’ philosophy of inspiring children with enthusiasm for investigative science. In 1979 Marjorie died. Waldo survived her for some twenty years, passing away on 26 May 1999, halfway through his one-hundredth year.
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177 In following the life and research activities of Semon it has been necessary to skip the inter-war discovery of one of the other great synthetic elastomers, polychloroprene (CR). This was due to the pioneering work of Wallace Carothers whilst he was working at DuPont. In fact, there is a double credit in the history of polymers due to this pairing since, not only did Carothers’ team at DuPont develop the first commercial synthetic elastomer, which is still technically important today, but also, a few years later, he was responsible for the discovery of arguably one of the greatest families of plastics ever commercialised. In view of his position as the second of the two great names in the field of synthetic elastomers, we shall look briefly at his life. He was born on 27 April 1896, the eldest of four children, in Burlington, Ohio. He was considered ‘bookish’ at school, but that was to underestimate his breadth of interests. As well as devouring every book he could find, he was fascinated by mechanical toys and he also loved music. His tastes were catholic, ranging from Bach to Gilbert and Sullivan. In high school his interests turned to chemistry and he built a laboratory in his bedroom. His father taught at Capital City Commercial College in Des Moines and it was there that Carothers went to study accountancy when he left school. He then moved to Tarkio College in Missouri to study chemistry, although, being short of funds, he used his accountancy knowledge to advantage by teaching it in his spare time. He must have been a remarkable student—possibly unique—because he was made head of the chemistry department whilst still an undergraduate. He graduated in 1920, obtained his Masters in 1921, and his Doctorate from the University of Illinois in 1924. He was then appointed a professor at Harvard where he began his serious research career into high polymers.
Tears of the Tree 178 It was during his time in Illinois that the tormented side of Carothers’ character surfaced; he filled a phial with cyanide, to be carried with him for the rest of his life as an escape route if his fits of depression became too much to bear. In 1928 DuPont broke new ground by setting aside a laboratory for pure research. The ‘blue skies’ approach was not unusual fifty years later, but at that time corporate research was very much ‘cash flow oriented’—as indeed it has become again more recently. The chance to forgo teaching and devote all his time to research was not to be missed and, at thirty-two, he was placed in charge of DuPont’s research division. It was known that he suffered from moods of deep depression and his staff was warned to look out for them, but his mentor, Roger Adams, believed that these could be controlled and that Carothers had much to give the world from his researches. He proved to be just half right. Dupont was aware of the work of Father Julius Nieuwland into the synthesis of chloroprene from acetylene via divinyl acetylene, and believed that this could be the precursor of a viable synthetic elastomer. (Natural rubber consists of monomers which have four carbon atoms joined in a line, with carbons two and three unsaturated in the cis configuration and with a methyl group attached to the second carbon atom; chloroprene has a molecular structure which can be described as exactly similar but with the branched methyl group replaced by a chlorine atom.) This became Carothers’ first project and in April 1930 the polymer was synthesised by one of his team, Arnold Collins. This had the anticipated ‘rubbery’ properties and, whilst these were somewhat poorer than those exhibited by natural rubber in many areas, it had a much greater oil resistance. This gave it a niche market and it went into production in 1931 as ‘Neoprene’, the first commercially successful synthetic polymer which is still in production today. The chemical name for the elastomer is polychloroprene,
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179 Neoprene being DuPont’s trade name, but, like Hoover, the word has now been accepted as generic. They even made some tyres from it in 1934. It should be recorded that Father Nieuwland was offered royalties by DuPont for his part in the discovery, but he refused since he was under a vow of poverty. With that problem quickly resolved (three years from the start of research to commercial production!), Carothers’ group turned its attention to synthetic fibres, specifically to find a replacement for silk, which was in short supply because of trade and political problems between the USA and Japan. He had postulated some years earlier that, if an acid and alcohol could condense with the elimination of water to produce an ester, it should be possible to make a giant molecule or polymer by linking diols to diesters. This was soon achieved by one of his team, Julian Hill, to give an early polyester, but the physical properties were too poor for commercialisation and Carothers turned his attentions to polyamides, replacing the diols with diamines. In 1934 the first successful fibres were made. Carothers’ team was working with over 100 different materials and he identified them by two numbers, indicating the number of carbon atoms in the diacid and diamine. In February 1935 he polymerised adipic acid (which contained six carbon atoms) and hexamethylene diamine (which also contained six carbon atoms) to give ‘specimen 66’, which had good physical properties when it was drawn into a fibre. The material was initially christened ‘Tiber66’, but in September 1938 it was renamed ‘Nylon66’. In three years of research Carothers’ team had created the first commercial synthetic rubber with the discovery of neoprene, and now they had done it in the plastics field with nylon. Carothers’ immediate superior decided to target just one initial market with this new product, and in May 1940 nylon stockings arrived in hosiery stores nationwide. At just over one
Tears of the Tree 180 dollar per pair, five million pairs were sold on the first day. When the United States entered the Second World War and arrived in the UK, a few pairs of nylons could buy anything! By then, however, nylon production had been directed towards the war effort, particularly parachute canopies, rot-proof cords, and life rafts, and the ladies had to wait a few more years to have an unlimited supply of seamless or fully-fashioned nylon stockings. The research work of Carothers and his team changed the world, but he could not cope with it even as it was and he never knew what he had achieved. His earlier bouts of depression and heavy drinking had destabilised him. He grew up in a very close relationship with his sister, Isobel, and then fell in love with a married woman, but, when she became available, he retreated to his parents’ house. He spent time in a psychiatric hospital and was advised to marry by his doctor. In January 1936 his sister died and soon afterwards he married Helen Sweetman, a coworker at DuPont. She and DuPont rapidly agreed that he needed hospitalisation, and after some treatment he was released to take a walking holiday in the Alps with his old friend Roger Adams. According to Adams he seemed to improve during this time, but relapsed on his return to the US, even though he was actively cared for by his wife, psychiatrist, friends, and colleagues. In the middle of April 1937 Helen told him that she was pregnant, and on 29 April of that year, alone in a hotel in Philadelphia, he cracked open his phial of cyanide and died believing that he was ‘morally bankrupt’ and that his work had been useless. Helen later gave birth to a daughter, Jane. Let us return to the story of the synthetics. The American contribution to synthetic rubber production during the war had been a vast amount of fundamental research together with production technology and plant, but, when the war finished in 1945,
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181 the cycle of cheap natural rubber returned, leading yet again to reduced commercial interest in the synthetics. It was left to Ziegler and Natta to reactivate the cycle in the early 1950s when they developed catalysts which enabled high-cis 1,4-polybutadiene to be synthesised. The third phase of production techniques had arrived (gas-phase reactions, emulsion phase, and now catalysed stereo-regular emulsion phase). In the early 1960s DuPont echoed the pre-war work of IG/Standard when, instead of copolymerising just ethylene and propylene to make ethylene propylene rubber (EPM) with no crosslinking sites, they included a small amount of ethylene norbornene which provided, after copolymerisation, olefinic crosslinking sites. This material was to be known as EPDM. The ‘M’ indicates that the main polymer chain is saturated and the olefinic double bond is part of the pendent norbornene group. In contrast, butyl rubber (IIR) is classified as an ‘R’ type because, although the main polymer chain contains no unsaturation from polymerisation of the isobutylene, the residual double bond from butadiene or isoprene does reside within that polymer chain itself. All of the elastomers discussed so far have been either homopolymers (that is, one monomer polymerised), or random copolymers of two (or three) monomers, but when some structure is fed into this randomness we get quite different properties. This is the principle behind some of today’s thermoplastic elastomers. In these materials there are soft ‘rubbery’ regions to provide extensibility, coupled with ‘glassy’ regions which serve as physical network junctions at their operating temperatures but melt when they are heated, thus making the material mouldable (or remouldable). These materials have been around for approaching thirty years and, in a world where recycling is king, they are taking an ever-increasing share of the elastomer
Tears of the Tree 182 market, with recent figures suggesting about 20% of the non-tyre market. In this brief summary of the synthetics many materials have been omitted, but one class must be mentioned since it is unique in containing no carbon. This is the silicone rubbers, introduced as early as 1944 and today ubiquitous, being found in almost every environment from the most hi-tech to every DIY fanatic’s toolbox. In order to provide some structure for the identification and naming of the vast numbers of synthetic elastomers which were being developed since the early days of PVC and polychloroprene, a classification system was introduced which is now an International Standard—ISO 1629. The last letter of the identification code defines the basic group to which the polymer belongs, whilst the earlier letters provide more specific information and in many cases define the polymer absolutely. For completeness it is outlined below.
‘M’ Group: Rubbers Having a Saturated–C–C–Main Chain IM:
Polyisobutylene (e.g. VISTANEX), a soft inert plastic. A low molecular weight material used as a plasticiser and adhesive. EPM: Copolymer of ethylene and propylene; the rubber-like materials have a wt/wt composition between 70–30 and 30–70. EPDM: A terpolymer of ethylene, propylene, and a diene or polyene giving pendent olefin groups as crosslinking sites (e.g. NORDEL). An ozone- and oxidationresistant rubber.
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CSM:
FPM:
CFM:
183 Chlorosulphonated polyethylene (e.g. HYPALON), containing both C–Cl and C–SO2CI groups. Cl content 20–45%; S content 0.5–2.5%. Optimum properties 30% Cl, 1.5% S. Ozone-resistant rubber also used in varnishes. Fluoro/fluoroalkyl groups on C–C backbone (e.g. VITON and FLUOREL, copolymers of hexafluoropropylene and vinylidene fluoride; e.g. TECHNOFLON, a copolymer of vinylidene fluoride and 1-hydropentafluoropropylene). As above, but containing Cl as well as F; vinylidene fluoride (VF): chlorotrifluoroethylene (CTFE) copolymer (e.g. VOLTALEF, KEL F). All the fluoropolymers are thermally stable and relatively inert.
‘O’ Group: Rubbers Having Carbon and Oxygen in the Main Chain CO: ECO: GPO:
Poly(epichlorohydrin) (HERCLOR H)—the parent material from which came ECO and GPO. Copolymer of epichlorohydrin and ethylene oxide (HERCLOR C). Copolymer of propylene oxide and allyl glycidyl ether (PAREL). All these materials have good heat resistance and excellent low temperature properties.
‘Q’ Group: Silicone Rubbers MQ: MPQ:
Polydimethylsiloxane; depending on the molar mass this can be an oil, wax, or rubber. As MQ, with the addition of phenylmethylsiloxane.
184 MPVQ: MFQ:
Tears of the Tree As above, but with vinyl groups. As MQ, but fluorinated. These are all relatively stable thermally, and because of their cold-cure characteristics they may be used as electrical insulants, seals, moulds, etc.
‘R’ Group: Rubbers Having an Unsaturated Carbon Backbone ABR:
BR:
CR:
IIR:
CIIR:
Refers to copolymers of butadiene and methyl methacrylate (e.g. BUTAKON ML) used to impregnate paper, but also includes the terpolymer with acrylonitrile (primer, before adhesive layer applied) and the tetrapolymer with styrene (used as a synthetic rubber). Poly(butadiene)—available as high cis (98%þ), high trans (98%þ), and anywhere in between. Can also have vinyl groups present at any level. General-purpose rubbers usually 90%þ cis or about 45% cis, 45% trans, 10% vinyl. High vinyls have some specialist uses. Poly(b-chlorobutadiene) (e.g. CHLOROPRENE, NEOPRENE). Two main types: ‘G’, amber in colour with large molar mass range centred at about 100 000; ‘W’, white, molar mass of narrower range and centred about 200 000. Used as an adhesive or where oil or ozone resistance required, e.g. gaskets, sub-aqua suits, etc. Copolymer of isobutylene and isoprene (BUTYL). Only a small amount of diene added (circa 5%) to give crosslinkable sites. Has a low gas permeability; hence uses in inflatable products, and as general-purpose rubber. Chlorinated IIR with 2–3% wt/wt halogen to decrease gas.
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185 BIIR: Brominated IIR }permeability and improve self-adhesion on building (e.g. HYCAR 2202, BUTYL HT 1066, 1088). Uses as for IIR. IR: Synthetic cis-poly(isoprene) (e.g. CARIFLEX, NATSYN, SKI3). cis level 90–99%, remainder trans and vinyl. General-purpose rubber. NBR: Copolymer; acrylonitrile and butadiene (e.g. KRYNAC, NITRILE). Available with a wide range of ACN loadings to alter hardness; oil-resistant applications. Also available is terpolymer (see ABR) and tetrapolymer with styrene. NR: Cis-poly(isorene) natural rubber, essentially 100% cis, trans/vinyl <0.1%. Contains about 95% polyisoprene. Various grades available. Also modified NR—PA, SP, OENR, ENR, DPNR. NR was the original generalpurpose (GP) rubber. SBR: Random copolymer of styrene and butadiene. Styrene level varies from 10% to 80%, but the general-purpose level is 23.5%. Many types available and the exact type identified by a numeric code. General-purpose rubber. Vast amounts used in tyres. Also available as terpolymer/ tetrapolymer systems (see ABR and NBR).
‘T’ Group: Rubbers Having Carbon (Oxygen) and Sulphur in the Main Chain OT:
Polymer of bischloroalkylether (or formal), with sulphur. Most common one uses bis-2-chloroethylformal; CH2(OCH2CH2Cl)2 (with a little 1,2,3-trichloropropane for crosslinking) THIOKOL ST. EOT: As above, but copolymerised with ethylene dichloride. All of these smell strongly of sulphur and are used for oil
186
Tears of the Tree and solvent seals. The liquid polymers cold cure and find a wide acceptance as sealants in the building trade. Popular ones include:
‘U’ Group: Polymer Chain Contains Carbon, Oxygen, and Nitrogen AU: EU:
Polyesterurethanes. Polyether urethanes. A wide range of materials used as oil-resistant materials, in oxidation-resisting applications, and as lightweight shoe soling.
Although not true elastomers, certain polymeric materials merit inclusion here because of their application as rubber-like materials. PVC:
PS:
Poly(vinylchloride); hard, brittle material (d ¼ 1.4) often copolymerised with vinylidine chloride, vinyl acetate, styrene, ABR, ethylene vinyl acetate, etc. for a wide range of applications. When plasticised, usually with esters such as phthalates, it becomes quite ‘rubbery’. Used in conveyor belts, paints, varnishes, floor coverings, erasers (rubbers), flexible tubing, wellington boots, and many cheap ‘rubber’ goods. Thermoplastic. Polystyrene; only occasionally met as a reinforcing plastic within a continuous elastomeric phase (e.g. shoe soling), but can be considered to be present in some thermoplastic elastomers such as the block copolymers: SIS (styrene-isoprene-styrene) and SBS (styrenebutadiene-styrene). Analytical data show that in both cases the styrene exists as ‘polystyrene’ rather than randomly dispersed styrene as in SBR.
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Chicle: Guayule:
187 A naturally-occurring mixture of cis and trans polyisoprene (25:75); with resins, used in chewing-gum. Natural cis-polyisoprene isolated from the shrub Parthenium argentatum by solvent extraction. Uses and properties as for NR, but smell reminiscent of gin. Efforts to develop commercial exploitation have not been particularly successful.
Although many people think that today’s world is ruled by synthetics and the natural material is dead, we have seen that its output has continued to grow throughout the last century. The synthetics have expanded more rapidly as demand for generalpurpose elastomers, which can replace or be blended with the natural material in many applications, has grown more rapidly than the latter can be produced, and also because ‘speciality elastomers’, which are used for a range of applications such as oil resistance or extended thermal stability for which natural and general-purpose rubbers are not suited, have been developed. In round figures there are currently about 6 000 000 tons of natural rubber and 9 000 000 tons of synthetics produced per year. This chapter concludes with a final thought. Most of the major synthetic elastomers of today are made from that finite material, oil. Natural rubber comes from a renewable resource, and chemical treatments of it are being investigated and used to enable modified natural rubber to operate in areas once considered to be the sole preserves of the synthetics. The biosynthesis of natural rubber also consumes the greenhouse gas carbon dioxide and it produces commercially useful timber as a by-product. As the graph in Fig. 9.1 shows, the story of the synthetics versus natural rubber is by no means over.
10 The Heavy Mob However much natural and synthetic rubber the world is able to produce it would be useless without the machinery to make something from it. Britain was lucky in that the industrial revolution had begun some years before Hancock started his experiments, but, in terms of the size and mass of the equipment required to process rubber, it was still in its infancy. In part, this was due to a lack of available and useable power. If the industrial revolution is defined as the application of power-driven machinery to manufacturing, the power was just not available. In 1853 Goodyear wrote: It is for want of adequate power and corresponding machinery for this purpose, and of that only, that the inventor is dissatisfied with the present state of manufacture.
In Europe, in the early part of the nineteenth century, applications were based on products which could be cut from either sheet or block rubber, or from products such as rubber bottles or shoes made originally from latex and imported from Amazonia. In America the major products on sale were overshoes imported from Para´. The discovery of solvents which could dissolve raw natural rubber to give a viscous syrup-like solution led to this being the major way forward, as can be seen by reading articles written towards the end of the eighteenth century, as well as Goodyear’s
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189 and Hancock’s autobiographies. Rubberised fabrics or articles made by dipping formers into the solutions provided the majority of products being manufactured. The equipment required for this was neither heavy nor had excessive power requirements; Macintosh began by painting rubber solution onto sheets of fabric with a simple brush, and when Hancock designed a spreading machine it was little more than a large table with a trough to hold the rubber solution followed by an open drying oven (see Fig. 10.1). Later, with the advent of Parkes’s ‘cold-cure’ process using sulphur chloride gas, the rubberised fabric was led through a loosely-sealed cabinet in which the vulcanisation took place. Hancock’s ‘pickle’, as described earlier, was the first important piece of rubber-manufacturing equipment, although, since it was man-powered and produced a few ounces of rubber per day, it could hardly be classed as part of the industrial revolution! Its purpose was to convert rubber scrap into a useable material and in
Fig. 10.1 A simple spreading table.
Tears of the Tree 190 this it succeeded admirably. It combined the scraps into dough which, as an unexpected bonus, was found to be much more soluble than the ‘unpickled’ rubber and to give high-quality solutions—much to the benefit of Macintosh and Hancock himself. This breaking down of the rubber became known as ‘mastication’ and is particularly important in the processing of natural rubber because the average size of the molecule is so large— ranging from 10 000 to over 100 000 monomer (C5H8) units— that they are unable to ‘untangle’ themselves and dissolve. Most of the synthetic elastomers have much shorter chain lengths— perhaps 2000 to 10 000 monomer units—and these will dissolve more easily. However, there was still no engineering industry able to meet the demands of the rubber product manufacturers. Indeed, it is fair to say that the two industries developed together as demands for multi-horsepower machines built to close tolerances grew from all areas of industry. Hancock was the first to introduce a power-driven machine into the rubber industry, and this consisted of a single roller with a fluted surface rotating in a concentric case, as shown in Fig. 10.2. As it rotated, the rubber was torn or masticated, as in his ‘pickling’ machine. This could claim to be the forerunner of today’s internal mixer. Hancock’s later models could handle up to 1800 pounds of rubber in one charge. Two later examples of this type of mixer, manufactured by Francis Shaw and David Bridge, are also shown in Fig. 10.3. In America in the 1830s Edwin Chaffee adopted a different approach. He had concluded that the use of a solvent to prepare cast thin films of rubber was the main cause of the latter’s rapid degradation, so he developed a machine which he called a ‘calender’. This had three or more rollers with adjustable ‘nips’ between the rollers, through which the rubber could be passed to
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Fig. 10.2 Hancock’s 1840 masticator. (a)
Fig. 10.3 Single-roller masticators manufactured by (a) Francis Shaw, and (b) David Bridge.
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192 (b)
Fig. 10.3 (Continued).
produce ever-thinner sheets (see Fig. 10.4). A sheet of fabric could be passed through the final nip together with the rubber, enabling rubber-impregnated fabric to be manufactured without recourse to any solvent. This illustration in Fig. 10.4 gives some idea of the size of these calenders. A crucial point to notice is that the calender squeezes the rubber like an old-fashioned mangle; normally there is no shearing effect between the rollers as they rotate at the same speed. However, some machines, such as the one illustrated in Fig. 10.4 and on the market at the beginning of the twentieth century, have the option of altering the rotational speed between the rollers, and if this is done between the final pair, between which the fabric passes, the rubber can be forced more easily into the fabric. This facility gives the machine its name—a shearing calender. The three-roll calender pictured in Fig. 10.5, the Iron Duke, is believed to be the first such machine built in Britain. It was built
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Fig. 10.4 A three-roll calender.
for Stephen Moulton in 1849 and was based on an American design. The company archives offer a clear insight into how far the manufacturers were pushing the frontiers of their science. In April Moulton wrote to the Bilston Foundry: I am glad to hear that two of the rolls are finished but how do you intend to grind the third? They must all be ground together in the same frame or otherwise they will not be true.
In July the foundryman complained of the expensive experience he was having (‘if you could see the number of rolls strewing our foundry yard you would not complain’) and informed Moulton
194
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Fig. 10.5 Moulton’s three-roll calender—the Iron Duke.
that: We find the friction so very great now that the rolls approach a smooth surface that we are compelled to abandon the machinery hitherto in use and remove the rolls to another place so that we may be enabled to have the direct power of another engine.
The problem would not go away. In the 1870s one manufacturer wrote, ‘The roll we had on our lathe has proved a waster, making the third.’ Another manufacturer, when Moulton queried the price, replied, ‘Rolls never seem worth their money. They are very risky things to make.’ Nevertheless, they were made and in number. Back in the 1830s, a year or two after Chaffee had developed the calender, he produced the two-roll, two-speed mill, which
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Additives Rubber
Fig. 10.6 Diagram of mastication and the addition of additives.
rapidly replaced Hancock’s machines and which was specifically designed to masticate the rubber. By rotating the horizontallyopposed rollers in opposite directions at slightly different speeds, the diagram in Fig. 10.6 shows how the rubber ‘bands’ on the left roller whilst, because here the right one is rotating slower than the left, the rubber will be sheared and ‘bulk up’ in the nip. The rubber is masticated by the shearing action, and any additives that are required can be poured in between the rollers at the nip so that they become finely distributed throughout the mix. For that reason these are sometimes called mixing mills. The calender and two-roll mill remain the basic equipment of virtually every rubber-manufacturing facility today and, although they may have changed with refinements such as heating or cooling for the rollers, the fitting of safety guards, and more modern designs of cover, the fundamentals remain the same now as they were one hundred and fifty years ago (see Fig. 10.7). The only significant advances are in the electrics. Although the illustrations in Fig. 10.7 are of quite large machines, they are manufactured in a vast range of roller lengths and diameters. A laboratory mixing mill might have rollers some four inches long and one inch in diameter, whilst a large industrial
196
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(a)
(b)
Fig. 10.7 (a) An early electric two-roll mill, and (b) a modern sixtyinch two-roll mill.
The Heavy Mob
197 mill might be one hundred by thirty inches, able to take up to four hundredweight (200 kg) of final rubber compound, and require a motor capable of delivering over three hundred horsepower. These mills had one particular disadvantage in that they were open to the atmosphere, and the search for new methods of mixing with more compact equipment which was quicker, less power-consuming, and which offered a cleaner working environment than the ‘open’ mill led to various ‘internal mixers’ being developed. Werner Pfleiderer, a company that had begun some thirty years earlier to manufacture machinery for mixing and kneading dough, made the earliest in 1913, while in 1916 Fernley Banbury launched the ‘Banbury’ mixer, which remains probably the most popular mixer for rubber compounding around the world today. The principle of operation is shown in Fig. 10.8(a). The Banbury used a pair of counter-rotating winged tangential rotors, which can be seen as pear-shaped objects, inside a closed chamber into which the rubber and additives could be dropped via the hopper on the left-hand side and then sealed under pressure by the vertical ram. After mixing, the compound was dropped through the floor of the mixer for subsequent moulding and vulcanisation. Diagrams never give a good idea of the sheer size of these machines, but Fig. 10.8(b) shows a photograph of a Banbury in use in an American tyre factory. The operator is dwarfed by its bulk. Francis Shaw adopted the same principle in the 1930s with the ‘Shaw Intermix’. The intermixer is a variation on the Banbury theme which uses rotors which intermesh and shear/mix the rubber between their nogs and root diameters. Since the nogs are slewed on the rotors, the mixing material is continually swept from side to side within the chamber to give excellent overall mixing.
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198 (a)
Fig. 10.8 (a) A diagram of a Bridge–Banbury, and (b) a Banbury internal mixer.
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199
(b)
Fig. 10.8 (Continued).
At least one manufacturer today incorporates both intermixing and tangential technology within one mixer, but rubber mixing still remains a batch process and no one has yet succeeded in devising a fully-continuous mixing process.
200
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Fig. 10.9 Three-mould hydraulic press.
The next stage in the manufacture of a vulcanised rubber product is to shape it and then apply heat to effect vulcanisation. In 1855 Johnson patented the idea of using a press with shaped platens to bring about the shaping. In 1860 Pitman introduced steam-heated platens, a practice still in use today, although electrically-heated presses have steadily increased in use since the latter third of the twentieth century. The final shape of the product depends only on the design and manufacture of the mould, although, in practice, the quality of the finished product can be crucially dependent on subtle details of the mould and the way in which the rubber compound flows to fill it.
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201 There are two basic types of moulding processes: compression moulding and transfer moulding. In compression moulding a slab of compounded rubber is placed in the bottom portion of the mould and the top mould is lowered onto it—thus compressing the slab to fill the mould. Any spare compound is forced out of the mould as ‘flash’, to be trimmed off later. In transfer moulding the compounded rubber is placed in a separate part of the mould (the transfer pot) which is connected to the mould proper by a series of small channels or sprues. A plunger then forces the compound through the sprues so that it transfers from the pot into the mould. As with compounding on a mill or in an intermixer, moulding with platens is a ‘batch’ process and this is obviously of little use in the manufacture of articles such as hoses or automotive rubber seals and profiles. In this area the rubber industry learned from the plastics industry, specifically from Bewley, who had invented the plastics extruder in 1847 to extrude gutta-percha as an insulating and protective coating for the first submarine telegraph cables. In 1881 Francis Shaw developed the screw extruder in which the compounded rubber was forced through an appropriatelyshaped die from a large cylindrical reservoir that was compressed by a screw piston. The product squeezed from the die (the extrudate) was then coiled on flat pans in spirals and cured in air ovens. More modern developments retain the extruder but use a variety of continuous-curing procedures. In Fig. 10.10 rubber compound is being mixed on a two-roll mill at the rear and a simple rod profile is being extruded. The final shape of the moulding, i.e. a car door seal, is infinitely variable, depending only on the die design. Surprisingly, it took over half a century for the extruder and shaped platens to be brought together in one machine in the process known as ‘injection moulding’. Although it had been used
202
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Fig. 10.10 Milling and extruding.
by the plastics industry since the 1870s, the process was not applied commercially to rubber until the 1940s, and it was only in 1957 that Arburg commenced series production of this type of machine. Early versions used either a simple ram or a screw ram to both inject the compound into the curing chamber and maintain pressure while the curing took place, but in the 1960s screw machines with separate rams were introduced by REP. These had a ‘V’ head design, with one arm of the ‘V’ being the screw extruder which forced the compound through a non-return valve into a small chamber, from which it was injected into the mould by a ram; this ram constituted the other arm of the ‘V’. This allowed a high degree of control over batch volumes and ram pressures, thus minimising wastage and improving product reliability. This type of machine is today fully automated and the industry standard. The schematic illustration in Fig. 10.11(a) shows how the rubber mix or compound is forced into the reservoir by the screw
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Ru
bb
Injec
tion
ram
(a)
er
mi
x
Rubber being forced into mould (b)
Fig. 10.11 (a) A schematic illustration of injection moulding, supplied by REP UK, and (b) a bathing cap being injection moulded.
Tears of the Tree 204 on the left as the ram on the right is withdrawn. The valve at the base of the screw then closes and the ram injects the mix into the mould. This chapter has so far been concerned almost entirely with the heavy equipment needed to process raw rubber—natural or synthetic—but in 1920 Philip Schidrowitz discovered how to prevulcanise latex. His product looked and behaved exactly as ‘raw’ latex, but when it was dried or coagulated and heated at a relatively low temperature, around 130 C, it gave a vulcanised product which had all the properties of conventionally vulcanised ‘dry’ rubber. This led to the birth of a new industry—the manufacture of a vast range of dipped rubber goods. Some are illustrated in Fig. 10.12. Modern dipping lines are fully automated and use formers made of wood, plastic, glass, or porcelain which can be interchanged to meet demand (see Fig. 10.13), although it is usual for one line in a factory to keep to one product. Pre-vulcanised latex can be sprayed onto fabric or formed in moulds with a blowing agent so that vulcanised latex foam products, such as soft rubber balls or toys (see Fig. 10.14), can be made. It is also possible to whip latex into a foam and cure that to give, for instance, latex mattresses. This process was first developed by E. A. Murphy, working for Dunlop, who discovered in 1929 that whipping bubbles into latex and then adding a gelling agent stabilised the foam. In 1931 the first mattresses were produced, but it was only in 1960 that the Talalay process (named after its inventor, Leon Talalay) was patented in the UK. This involved a sophisticated manufacturing process—mechanical foaming followed by vacuum expansion, then freezing and gelling with carbon dioxide in specially designed moulds containing dozens of heated probes. The probes were an essential practical,
The Heavy Mob (a)
205
(b)
(c)
Fig. 10.12 Batch dipping of (a) bathing caps, (b) catheters, and (c) balls and bladders.
Fig. 10.13 Modern continuous production of dipped medical gloves.
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Fig. 10.14 Various toys made from latex.
rather than design, feature which overcame the difficulty of uniformly heating a large block of such a thermally insulatingmaterial.
11 Chemicals and Curatives This chapter provides a brief and necessarily superficial look at the history of vulcanisation. Its intent is not to educate chemically but to describe in as non-technical a way as possible the changes which have taken place from the first faltering steps of its infancy, guided by Goodyear and Hancock, to its full maturity today. Without this process our rubber would be useless. There can be no doubt that the discovery of vulcanisation of high polymers with unsaturated carbon backbones (polyolefinic elastomers), such as natural rubber, changed the world as much as, if not more than, any other discovery over the last few hundred years. In non-chemical terms, vulcanisation can be described as the process by which the chemical reaction between a polyolefin and sulphur results in greatly increased elastic properties of the polyolefin and the maintenance of these properties over a comparatively wide temperature range. It has already been mentioned that the actual term ‘vulcanisation’ was suggested by William Brockedon to Hancock in the UK, although it is now accepted that the action of sulphur, certain metal oxides, and heat on natural rubber to ‘cure’ it of its propensity to turn brittle when cold and sticky when hot was discovered by Charles Goodyear in 1839. Indeed, in the US the terms ‘cure’ and ‘curing’ tended to be used interchangeably with ‘vulcanise’ and ‘vulcanising’. This has resulted in a number of anachronisms which will be addressed later.
Tears of the Tree 208 In the light of what has been written about vulcanisation in previous chapters, the first point of note is that heating pure rubber and sulphur will not give a vulcanised product. Pure rubber in this context means just the polymeric material, but since natural rubber, even after normal cleaning and ‘purifying’, is only about 95% pure, the experiments of Goodyear and Hancock were successful. The reason lies in the presence of natural proteins in the rubber which act as ‘activators’ to start the vulcanisation process. Hancock’s work showed that this was all that was needed, but Goodyear found that lead oxide also assisted the process. Unknown at the time, other natural materials in the rubber—long-chain organic fatty acids such as stearic acid—were also involved in the complex chemistry. In 1881 Rowley patented ammonia as a promoter for the vulcanisation reaction, but for obvious reasons this did not prove popular and it was some twenty years later before anyone suggested using the less volatile organic base, aniline, as its replacement. Unfortunately, its toxicity ruled it out very quickly, although it had also been patented in 1908 as an antioxidant, a pointer to the way forward on this front which will be returned to in a later chapter. In 1911 Bayer suggested another base, piperidine, but again this was rejected commercially because of both its smell and toxicity. In the early 1920s there were great advances with the discovery that diphenylguanidine (DPG) and mercaptobenzthiazole (MBT) greatly assisted vulcanisation. This type of chemical became known as an accelerator; however, in one sense the word is inappropriate because, although it did make the reaction proceed more rapidly, it also enabled the operator to have much more control of the vulcanisation chemistry. Perhaps the origin of the word ‘accelerator’ can be laid at the door of Peachy, who patented nitrosodimethylaniline in 1914 under the name ‘accelerene’.
Chemicals and Curatives
209 Several other accelerators were soon introduced, such as the thiurams and xanthates, and in 1923 Bruni and Hopkinson, working in Italy, introduced the zinc dialkyldithiocarbamates (ZDRC), where R could be methyl (M), ethyl (E), or an extended range of alkyl groups. These accelerators, together with DPG and MBT, all of which were developed in the first half of the 1920s, remain the accelerators of choice for many applications today. One further patent is worthy of note. Again in 1923, Russell patented a combination of fatty acids and zinc oxide to assist in vulcanisation, and this completed the fundamental rubber vulcanising system: a polyolefinic rubber, sulphur, an activator—fatty acid with zinc oxide, an accelerator—GDPG, MBT, ZDRC, etc., used singly or in combinations. Apart from the obvious reason of patenting a new accelerator to obtain a slice of an existing market, the reasons for developing new ones tend to be threefold: 1. to modify the vulcanisation process in such a way as to make it more cost-effective; 2. to modify the vulcanisation chemistry and thereby obtain a product with improved performance characteristics; 3. for environmental or ‘health and safety’ reasons. Although the development of this basic vulcanisation system had followed logical and progressive lines of research, the actual chemistry remained a mystery—if indeed it was chemistry at all! For close to a century after the discoveries of Goodyear and Hancock the argument raged as to what was the interaction between rubber and sulphur. In 1898 Ostromislenski proposed a
Tears of the Tree 210 combined chemical/physical theory of vulcanisation, in 1902 Weber proposed a purely chemical one, and in 1910 Ostwald opted for some sort of physical mixture or ‘alloy’ formation. Although the evidence for a chemical inter-reaction became overwhelming for most scientists, there were still arguments between the various camps at an international conference on vulcanisation as late as 1939. The chemical structure of the natural rubber vulcanisate was finally resolved during the 1960s and 1970s at the Malaysian Rubber Producers’ Research Association (now the Tun Abdul Razak Research Centre or TARRC) by studies of the reactions between combinations of sulphur and various accelerators with low molecular weight olefins, the last being taken as models for the monomeric rubber olefin unit. This work led to the conclusion that the polymer chains of an unvulcanised rubber were joined together (crosslinked) by sulphur bridges to give a three-dimensional network, and it was this which provided the increased elasticity of the vulcanised product. At this point it should be noted that, because a rubber product can contain a range of substances which are not part of the vulcanisation process, it is the ratio of sulphur to accelerators and to the rubber which is important in defining the type of vulcanising system. Thus quantities in a rubber mix are expressed not as percentages of the total but as ‘parts by weight per hundred parts of rubber’, generally abbreviated to ‘phr’. The detailed picture which emerged was extremely complex but a simplistic picture can be drawn to advantage. The first stage of the vulcanisation process is the reaction between elemental sulphur, the accelerator, and the activators to produce the ‘active’ sulphurating agent. This then attaches itself to one of several carbons within one of the monomer units of the polymer, whilst the other end of the sulphur chain is doing the same to another
Chemicals and Curatives
211 monomer unit. The expression ‘sulphur chain’ is significant as there could be many more than one sulphur atom joining together to form this linking chain or bridge. It is possible that the bridge might not be formed between two adjacent polymer molecules at all, as it could have looped back and coupled to the same polymer chain to which the first attachment took place. However, even this is not the end of the story. Chemistry which takes place at the vulcanisation temperature of 160 C and above will continue, albeit at a much slower rate, at ambient or product-operating temperatures. The sulphur–sulphur bonds in the sulphur bridge are relatively unstable and can break and re-form. If they rejoin where they broke then that has no effect, but if they join up with another ‘free’ sulphur atom there will result changes in crosslink lengths and possibly the formation of more crosslinks or chemical modifications to the polymer chain. In order to ‘visualise’ the chemical changes which occur during crosslinking and to observe how changing the chemicals and their relative proportions can alter the properties of a vulcanisate, an instrument called a rheometer is used. There are several types available but they all provide a measure of the stiffness of the rubber mix as it vulcanises. A typical printout from a Monsanto rheometer is shown in Fig. 11.1. The mix, when placed in the instrument, has a particular stiffness (A), but as the temperature rises it falls (B). Between B and C the chemistry which the mix is undergoing does not introduce crosslinks, but these start being formed at C and continue with time to give the maximum vulcanised state at D. The difference between the stiffness at C and D indicates the degree of crosslinking or crosslink density. As heating continues, between D and E there is a fall in the crosslink density as the various chemical reactions mentioned earlier take place. This is called reversion. At any temperature and for any combination of curatives, such an instrument will show very quickly what the final crosslink
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212
D
‘Stiffness’
E
A B
C Time (arbitrary scale)
Fig. 11.1 A rheometer printout for the vulcanisation of a ‘conventional’ mix.
density will be and how long the heating should continue to give that required state—information Goodyear, Hancock, and their competitors would have given a great deal to have had. An appreciation of these factors now enables us to understand some quantitative observations obtained almost a century ago. In the early days of vulcanisation, before the introduction of a range of modern accelerators but when the advantages of adding a little organic base were appreciated, trial and error had shown that around 2.5 phr sulphur gave a good useful vulcanised rubber product, and this came to be known as a conventional vulcanisate. This level of sulphur is used today with around 0.5 phr accelerator, but a combination of model olefin studies with calculations of the crosslink density of the vulcanisate have shown that this is not a chemically efficient system. The polysulphidic crosslinks and other non-crosslinking sulphur chemistry mean that there are about twelve sulphur atoms consumed to produce one crosslink. If the levels of the ingredients are reversed to 0.5 phr sulphur and 2.5 phr accelerator then we have a much more efficient vulcanisate (EV), with only about three sulphurs required for
Chemicals and Curatives
213 each crosslink. Not surprisingly, it is possible to design ‘semi-EV’ systems which fall between the two extremes. Zinc oxide is today the preferred inorganic base, usually added at around 5 phr, although for applications where transparency is desired (baby feeding teats, medical tubing, etc.) it can be as low as 1 phr. Just because the terms ‘conventional’ and ‘efficient’ are used these should not be equated with ‘old’ and ‘new’ (better). The different systems give different properties to the vulcanisates at the same level of crosslinks (crosslink density) and the system chosen will depend on the anticipated use of the product, bearing in mind the changes which might occur during its service life. Various properties can also be adjusted by altering the number of crosslinks inserted into the vulcanisate during manufacture, all other factors being constant. For instance, stiffness and hardness will increase with increased crosslink density, as will resilience. Resistance to abrasion will also increase, but so will the likelihood of fatigue cracking. Properties such as the extent of elongation before the product breaks, heat build-up during work, swelling in solvents, creep, and set will all decrease. If the cure system chosen gives an increase in average sulphur chain length, that is, as one moves from an EV system to a conventional one, then creep and set will increase, as will the product’s resistance to tearing and its resilience, but its heat and thermal ageing, together with its fatigue resistance, will all fall for the service-ageing reasons discussed earlier. By now the subtle complexity of the chemical vulcanising components of a particular rubber vulcanisate will be appreciated. It requires a detailed knowledge of many features of the service life and design expectations of each product to select the optimum combination of chemicals. Many rubber vulcanising systems which have used chemicals other than sulphur have been investigated over the last 150 years, but very few exist commercially today and here we tend to move
Tears of the Tree 214 from the word ‘vulcanisation’ to ‘cure’. The use of sulphur chloride (the Parkes process of 1846) is described as the sulphur chloride cold-cure process, whilst processes such as those which occur in the ubiquitous cycle-repair patch tend also to be designated ‘cold cure’. We also have peroxide- and radiation-cured (rather than vulcanised) rubbers. To add a further layer of complication, the chemicals which may be added to a rubber mix to effect vulcanisation, including the accelerators, are collectively called curatives, and the remains of these chemicals after vulcanisation are called cure residues. It should be remembered that early stories of the preparation of ‘dry’ rubber from latex in South America involved the smoking over open fires of layers of rubber built up on ‘paddles’ and, indeed, smoking sheets of coagulated and semi-dried natural rubber in smokehouses (see Fig. 11.2) is still practised today in the Far East. This process was familiar to the British as it mirrored that used to smoke or ‘cure’ fish. Inevitably, therefore, the smoking process for rubber also became known as curing and for some time the two quite different meanings were used with much confusion. Eventually, it became accepted that ‘curing’ only referred to the reaction with sulphur and the other process was called ‘smoking’. In the previous chapter it was noted that in 1920 Peter Schidrowitz discovered that natural rubber latex could be vulcanised over a period of several hours (or days) by the addition of the usual ingredients—sulphur, zinc oxide, and an accelerator—to latex, either as it came from the field after stabilisation or after concentrating it to remove about half its water content, the precise timescale being dependent on the latex temperature. Visually, the vulcanised latex appeared indistinguishable from the untreated material, but when it was coagulated and dried it was found to behave as if it was vulcanised. The
Chemicals and Curatives
215
Fig. 11.2 Sheets of natural rubber after smoking in a smokehouse.
procedure of treating the latex in this way is called prevulcanisation, and the further short heating period after coagulation is called post-vulcanisation. The chemistry of this process was finally understood in the 1990s, again following work at TARRC in the UK. It was shown using transmission electron microscopy that initially there was crosslinking between the elastomer chains within each particle of latex which, as the particles were widely separated, did not affect the individual identity of each. However, when the latex was dried to a film, which brought the individual latex particles into intimate contact, loose ends of the polymer chains which ‘waved free’ from the particle acted like VelcroTM to hold the particles together. Slowly at room temperature, or more rapidly at elevated ones, the vulcanisation chemistry described earlier continued with S–S bonds in the
Tears of the Tree 216 polysulphidic crosslinks breaking and reforming. Some of the reformed bonds were inevitably between the entangled polymer ends of different particles and the whole product then became chemically ‘fused’ together. There are two particular advantages of vulcanised latex over vulcanised ‘dry’ rubber. Firstly, the latex tends to be very much stronger and elastic as the polymer chains have not been degraded by the mechanical work needed to incorporate curatives into the dry material; and secondly, since both pre- and post-vulcanisation take place at relatively low temperatures (the latter generally below 130 C), it is possible to incorporate colouring chemicals which would not survive the high temperatures used for costeffective conventional vulcanisation (typically 160 C to 200 C). The mixing or blending of two or more elastomers together during the manufacture of a rubber product is considered in the next chapter. However, here it should be noted that, whereas some blends can be considered almost completely compatible and, within specific performance limits, interchangeable (for instance, natural rubber, polybutadiene, and styrene butadiene), there are cases when synthetic rubbers such as nitrile, polychloroprene, and ethylene propylene rubber are blended with natural rubber to improve particular properties, such as oil resistance or longevity. These elastomers are naturally incompatible with natural rubber. The important practical result of this incompatibility is that the properties of the finished product are not those one would expect from a simple mathematical extrapolation of the individual ones and, indeed, are usually significantly inferior. It was long suspected that this was due to an uneven distribution of crosslinks between the elastomers of the blend, owing to the preferential solubility of the vulcanising ingredients in one or other of the elastomers. Until recently there was no means by which this could be measured as physical testing
Chemicals and Curatives
217 methods would always give a ‘composite’ value. In the 1980s a technique was developed which used nuclear magnetic resonance spectroscopy to measure the individual contributions from the crosslink densities of each elastomer, and the results confirmed earlier suspicions. Thus, with a blend of natural and nitrile rubbers, it was found that the crosslinks were virtually all in the nitrile rubber due to the greater solubility of the vulcanising agents in this more polar material, whilst the natural rubber was essentially uncrosslinked. This was later confirmed using a microscopical technique originally developed by Shiibashi in 1987 in which the vulcanised rubber blend is swollen in styrene, which is then polymerised to ‘lock’ the elastomer blend in its swollen state. Sectioning, staining, and examination using a transmission electron microscope (TEM) enables the effect to be ‘visualised’.
200 nm
Fig. 11.3 A vulcanised blend of natural rubber and nitrile rubber.
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218 (a)
2 m
(b)
2 m
Fig. 11.4 (a) A two-phase polymer system with weak bonding (white areas) between the phases. (b) A three-phase polymer system where the third polymer (thin black line around the white areas) acts as a ‘compatibiliser’ between the other two phases.
In the micrograph shown in Fig. 11.3 the natural rubber phase is the lighter, more open, mesh whilst the nitrile rubber is the darker, tighter, mesh. Indeed, the mesh structure in the latter is difficult to see because it is so compact. The lower the crosslink
Chemicals and Curatives
219 density the more the elastomer will swell, so the natural rubber is lightly crosslinked and the nitrile is heavily crosslinked. The ability to observe and quantify these effects enabled alternative vulcanising agents, or mixtures with varying polarities, to be investigated and a more equal distribution of crosslinks obtained. This inevitably led to an improvement in the properties of the blends. Further valuable information could be obtained from this technique. In the micrograph shown in Fig. 11.4(a), obtained by the same swelling technique as that described above, an ‘S’-shaped white edge can be seen between the two elastomer phases. This is caused by the two phases tearing apart and would account for the premature failure of the product. In Fig. 11.4(b) a faint black line can be seen around the discrete phase particles; this is a third elastomer which is reasonably compatible with both the others and was added to act as a compatibiliser or ‘glue’, holding the phases together.
12 Padding or Performance Enhancer? With the exception of dipped goods, it is usual for most commercial rubber products to contain appreciable levels of two other types of materials, namely fillers and plasticisers or extending oils. The former are generally inorganic, although carbon black is the obvious exception to the rule! In the absence of black, the fillers can be further separated into neutral or brightly coloured. Some idea of the range of materials used at the turn of the twentieth century is given by the advertisement shown in Fig. 12.1, which appeared in 1909. Inorganic powders have been used to dust rubber surfaces, and so reduce their stickiness, since the first Mesoamericans used rubber to fabricate balls and, no doubt, many other articles. Initially, they would just have used dried powdered earth, and little changed until the nineteenth century when Thomas Hancock began to study the effect of a range of inorganic chemicals on rubber surfaces. However, it was not until he invented his masticator and Edwin Chaffee developed his mixing mill that it became relatively easy to intimately disperse virtually any powder in a rubber matrix. Before that it had required dissolution of the rubber, incorporation of the additive, and then removal of the solvent, a process known to give a relatively poor-quality product.
Padding or Performance Enhancer?
221
Fig. 12.1 An advertisement for rubber fillers which appeared in the early twentieth century.
Tears of the Tree 222 Charles Goodyear did not become interested in rubber until after the inventions of Hancock and Chaffee, but he again initially investigated surface treatments before turning to bulk fillers in an attempt to stop the stickiness of the rubber. Hancock’s patent for vulcanising rubber has already been mentioned and the point made that the title contains no specific reference to this process. In fact, the long patent, running to over three thousand words, is at least in half concerned with the incorporation of magnesium silicate (talc) and other inorganic fillers, as well as powdered asphalte, into rubber. The final summary is concise; he claims: Firstly the combination of caoutchouc with silicate of magnesia, whereby manufactured caoutchouc is rendered free from that clammy and adhesive character which it usually possesses. Secondly I claim the modes herein described of combining asphalte with caoutchouc; and, Thirdly I claim the treating of caoutchouc (either alone or in combination with other substances) with sulphur when acted on by heat, and thus changing the character of the caoutchouc as herein described.
In Goodyear’s book of 1855 he mentions using magnesia, lime, and white lead, as well as various colourants such as chrome salts. With the discovery of vulcanisation, and the realisation that rubber products could actually have a reasonable life expectation, the demand for them began to grow. With the raw material being in short supply and therefore expensive, anything which could be done to ‘bulk it out’ with cheaper materials and which did not detract too much from its expected properties was welcomed by the manufacturers. Since vulcanisation removed the problems related to the sticky rubber, there was no longer any need to add fillers to prevent this, but it was still not appreciated that certain fillers could actually improve the properties of a vulcanisate.
Padding or Performance Enhancer?
223 Hancock maintained that pure rubber goods were always the best, although with some contradiction he advocated the incorporation of (not the coating with) linseed oil or stearine to improve surface finish. As late as 1882 Hoffer was describing how fillers could be used only for cheapening, as colourants, or to make abrasives by the addition of sand or emery powder. It was left to Heinzerling and Pahl, in 1891, to carry out a classic experiment in which they prepared a range of vulcanisates containing most of the common fillers in use at that time and compared their properties. They were able to reach certain conclusions which had a degree of validity, but, with the absence of any test data on crosslink density, they missed a crucial fact. A number of the fillers used had an effect on the vulcanisation process, some accelerating it and others retarding it. Since they used identical vulcanising conditions, they were not comparing test pieces with identical crosslink densities. However, they certainly had a valid claim when they reported that zinc or magnesium oxide ‘strengthened’ the vulcanisate more than a filler such as silica. It also became obvious that the quality of the fillers was sometimes suspect and that certain impurities such as copper, manganese, nickel, chromium, and cobalt salts could have a very deleterious effect on the longevity of a vulcanised product. By the 1920s most of the fillers in use today—talc, chalks, clays, and barytes—had been evaluated and adopted by the industry, although one relatively modern material, titanium dioxide, only started to be commonly available in the early 1950s. This white powder had, and continues to have, two significant advantages over filler levels of zinc oxide, although not replacing it as a vulcanisation activator. It has a much higher tinting strength, i.e. it is a ‘brighter’ white pigment, and it lacks any toxic properties. With the advent of the motor car came demands for a tyre which would last more than a few months. This required a
Tears of the Tree 224 ‘strengthening’ or reinforcing of the rubber way beyond that which then could be obtained by the use of the various inorganic fillers. Carbon black was about to come into its own. Carbon black had, of course, been known for centuries and was used by the Chinese and Egyptians to make inks and eye make-up. They burned resins, fats, and oils under inverted pottery cones and collected the soot which became deposited on the pottery surface. Today this soot is called ‘lampblack’. Not surprisingly, ink-making was its primary use when large-scale production started in the US, with natural gas, associated with petroleum deposits, being the source raw material. Both Goodyear and Hancock had used this as a colourant and at filler levels without noticing its reinforcing or strengthening properties, although it is fair to comment that the reinforcing effect of lampblack is minimal when compared with types or grades of black which were developed later. A variation on the lampblack process, manufacturing what became known as ‘channel black’, was invented by McNutt in 1892, also in the USA, and this found its market in the ink and printing-ink business, as well as in the rubber industry. It has already been mentioned that in 1895 the first motor vehicle specifically designed to run on pneumatic tyres took part in the Paris to Bordeaux (and back) race. In spite of accumulating twenty-two punctures, it finished a creditable ninth from a field of forty-two. The era of air-filled tyres had dawned and by the end of that century most of the western tyre manufacturers who are household names today were manufacturing pneumatic tyres: Dunlop in 1889, Michelin in 1895, Goodrich in 1896, Goodyear in 1898, and Firestone in 1900. In 1887 Moseley patented ‘Flexifort’, a tyre cord with 98% warp and 2% weft, which eliminated the problems of abrasive degradation associated with conventional fabric-reinforced tyres. This was immediately
Padding or Performance Enhancer?
225 adopted by Dunlop for its tyres, but the standard warp:weft fabric continued to be used by many manufacturers through to the end of the First World War. In 1904 S. C. Moke, working at the India Rubber, Gutta Percha and Telegraph Works at Silvertown, showed how carbon black could be used to give a remarkable increase in the mechanical strength of a rubber vulcanisate. However, it was a number of years before this was adopted by the tyre industry in general, probably only when tread wear took over from tyre-fabric wear as the major cause of short tyre lives. In 1916 Brownlee and Uhlinger introduced a new process whereby the gas was injected directly into very hot ovens, and they found that by changing conditions a wide range of particle sizes could be obtained. These were called ‘thermal blacks’ and this type included the largest of all the black particles. A third process was developed in 1922 by the Colombian Carbon Company which again burnt gas but in a furnace, giving rise to their designation as ‘furnace blacks’; the combustion of acetylene was found to give yet another type, ‘acetylene black’, which found a use in the manufacture of electrically-conductive rubber. In 1923 Frank and Marckwald prepared vulcanisates which were identical in all respects except that one contained German lampblack and the other contained American oil black. They found that their physical properties were significantly different, with the former giving a more elastic product and the latter a much tougher material. It was realised that carbon blacks produced by different routes and from different starting materials gave a range of products that differed not only in particle size but also in structure and purity. By varying the type of black used in an otherwise consistent mix, it was possible to impart a wide range of different physical properties
Tears of the Tree 226 to a rubber product, and today blacks are available in many grades, the correct choice of which is of crucial importance to the performance of the finished product. Of these blacks, all but channel black are still manufactured, although furnace black, now manufactured by the oil furnace process, is by far the most important, probably accounting for over 95% of the world’s production. Of this, some 70% is currently used in the production of tyres and other automotive products, whilst around 20% goes into rubber products such as hose, belting, and engineering applications. A few of the basic types of black are listed below, but within each of these, several subtly different grades of blacks are available. Black type
Particle size (nm)
Raw material
Channel black Acetylene black Super-abrasion furnace black High-abrasion furnace black Fast-extruding furnace black General-purpose furnace black Thermal black
10–30 35–70 10–19 26–30 40–48 49–60 150–500
Natural gas Acetylene Natural gas Natural gas Natural gas Natural gas Natural gas
or or or or
oil oil oil oil
The divisions above are made according to particle size, but this is idealistic since, although the individual particles approximate to spheres in shape, they are rarely seen individually as they fuse together in chains or clusters, referred to as aggregates. These in turn tend to cluster together in agglomerates, which are believed to break up on mixing with rubber. Aggregates, on the other hand, may occasionally fracture, but in essence represent the units of carbon found within a vulcanisate. The type of aggregate indicates the structure of the black, which may be considered to
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227
500 nm
Fig. 12.2 A representative virgin carbon black as seen using a transmission electron miscroscope.
reflect the ratio of the surface area exposed to the rubber molecules to that hidden from the rubber inside pores or channels too small for the rubber molecules to penetrate; the higher the structure, the greater the number of particles per aggregate. There are thus four parameters which affect the way in which the black modifies the performance of a vulcanisate: the basic particle spherical size, the structure, related to the shape and size of the aggregate, the absolute surface area, and the area actually available for rubber–black interaction. The black manufacturer must control his processes precisely and, as has been said previously, the manufacturer of the rubber product must know exactly what its service life is going to require before he can decide which type and grade of black to use. Although it has been said that fillers were originally added to ‘bulk out’ a formulation, no mention has been made of what level
Tears of the Tree 228 constitutes a ‘filler’. Small additions make no real contribution to quality or cost, although they may on occasion be used to fine-tune the properties of a vulcanisate so that it meets some specification. Inorganic fillers were, and still are, added at levels typically between 25 phr and 150 phr, although in certain applications, such as rubberised carpet backings where the elastic properties are utilised to a minimum, levels of up to 600 phr have been seen. Goodyear mixed magnesium oxide with rubber to such an extent that he was able to make buttons and knife handles from the stiffened product. Titanium dioxide has been mentioned as a filler, but it is expensive and when white goods are required it is commonly used at relatively low levels, perhaps 5–10 phr, as a ‘brightener’ in conjunction with another ‘bulk’ filler such as chalk or talc. Carbon black can be used just as a colourant at levels of 1% or so, but for reinforcing purposes it normally falls in the same range as the inorganics, namely 25–150 phr. As the black loading of the rubber increases, so does the stiffness of the final vulcanisate. To counteract this effect, oil can be added, thus reducing the rubber content even further. A ‘play-off’ of black and oil loadings can be used to manipulate the performance and durability of a particular product. Perhaps the most simplistic example of this would be to compare the life expectancy of a Formula one racing-car tyre with that of an average family runabout (although that is only a fraction of the story). Historically, the oil used in the rubber industry was known as an extending oil, whilst the oil used in the plastics industry was called a plasticiser. Nowadays, particularly since the advent of polar rubbers such as polychloroprene and the nitriles, the distinction has become blurred. However, it is crucially important that the correct type of oil is used for each elastomer in order to achieve the desired effect. Given the propensity of rubber product manufacturers to add almost anything available to the basic rubber mix in the hope of
Padding or Performance Enhancer?
229 producing some particular advantage, it is not surprising that as soon as synthetic elastomers became available they too were mixed with natural rubber to give a blend of elastomers, and today the elastomeric component of many products is such a blend. Modern tyres are extremely complex in that different elastomers or elastomer blends are used in different parts of the tyre—the tread, sidewall, liner, bead, etc.—and the tread is often a two-or three-elastomer blend of natural rubber, styrene butadiene rubber, and butadiene rubber in almost any ratio one cares to choose. Overall, some 70% of the world’s production of polybutadiene goes into treads and sidewalls, about the same proportion as for natural rubber. The advantages of polybutadiene rubber are good abrasion resistance, which leads to low tread wear, and a low rolling resistance, which means good fuel economy. However, it also has relatively poor wet traction properties. Different manufacturers and consumers have different priorities and these dictate the blend ratios with natural rubber or styrene butadiene which are available throughout the world. The problems of preferential migration of cure chemicals into one phase of an elastomer blend have been highlighted as one cause of unexpectedly poor physical properties in these blends, but there is another factor and that is the compatibility and morphology, or form, of the blend. Two examples are illustrated in Fig. 12.3. In Fig. 12.3(a) there is an example of a blend of two elastomers where the two phases are described as co-continuous. The sample has been treated to remove one component and the remaining component has the appearance of a sponge. Essentially the same effect would be seen had the other elastomeric component been removed. The micrograph in Fig. 12.3(b) was taken at a lower magnification and using a different technique to identify the phases. Nevertheless, it
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230 (a)
2 µm
(b)
20 µm
Fig. 12.3 A Micrograph of (a) a two-elastomer co-continuous blend, and (b) a two-elastomer blend showing one discrete (dark) phase and one continuous (light) phase.
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231 is clear that there is one pale elastomer matrix, with the second elastomer existing as discrete units within the matrix. Moving from the blending of different elastomers to the blending of an elastomer with a non-elastic polymer (a plastic) seemed an obvious next step, and this resulted in a new class of materials, the thermoplastic elastomer. These perform as one would expect from a vulcanised elastomer at ambient or nearambient temperatures, but, unlike a vulcanisate, they can be remoulded when heated above the melting temperature of the plastic. Such a material was first made by Thomas Hancock in 1848 when he mixed natural rubber with gutta-percha, a naturally-occurring polymeric substance with the same chemical formula as natural rubber but with the atoms in a different spatial arrangement, but it seemed to have no commercial use and the concept lay dormant for over one hundred years until the advent of modern synthetic plastics. The rebirth began in the 1960s in the plastics, rather than the rubber, industry when low levels of elastomers such as polyisobutylene, butyl rubber, and ethylene propylene rubber (EPDM) were blended with the plastic polypropylene (PP) to overcome the low-temperature brittleness of the latter. These were called ‘impact-modified plastics’. Soon the whole ratio range was investigated and at the other end of the scale polypropylenemodified EPDM was patented in the early 1970s. The use of natural rubber in similar blends also began in the 1970s and this type of thermoplastic elastomer is available commercially today. It is not surprising that these and similar materials are making considerable inroads into certain areas which were previously the prerogative of the vulcanised material as they offer considerable advantages in recycling and waste management, not least the absence of sulphur. The main limitation is their restricted operating temperature range which, for practical
Tears of the Tree 232 purposes, cannot be considered to be much above ‘hot’ ambient. Chemically-modified natural rubber has also been blended with polypropylene to provide an oil-resistant thermoplastic elastomer, whilst a material in which the natural rubber phase is vulcanised during the blending process gives a ‘hybrid’ material with improved properties, but which is still able to be ground and reprocessed. There are other types of thermoplastic elastomers available commercially where the polymer chain itself is synthesised to have elastic and plastic regions, but these obviously do not involve the natural material and are thus outside the scope of this book. There is one other chemical which may be added to rubber, natural or synthetic, at relatively high levels but which is neither a filler nor a plasticiser, and that is sulphur. The levels used to vulcanise rubber have been considered in some detail and rarely rise above 3 phr; but when it is added at considerably higher levels, typically 25–50 phr, a quite different material is produced, and that is ebonite. This hard material is known by a number of names including vulcanite, preferred by collectors, and hard rubber, preferred in the US. Its origins are obscure. Various eighteenth-century scientists prepared hardened rubber, but it seems likely that these were mostly the heavily-oxidised material. The first record of rubber possibly reacting with a sulphur-containing chemical was made by Roxburgh in 1801, who obtained a white inelastic material when he passed chlorine into a solution of rubber in carbon disulphide and then poured the solution into water, but there is no analytical data to show that this was ebonite. In 1831 Leuchs added rubber to molten rubber and got a violent reaction, resulting in a coallike hard mass which might just have been ebonite, but he did not pursue the chemistry further.
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233 Nathaniel Hayward introduced Charles Goodyear to sulphur when he showed that dusting rubber with sulphur and exposing it to sunlight (the ‘solarisation’ process) gave it a hard skin, and this could well have been an ebonite skin. In fact, Ludersdorff had done exactly the same thing some years previously, but not in Goodyear’s presence. The first authentic samples of ebonite were prepared by Thomas Hancock some time prior to 1843, and the details are given in his ‘vulcanisation’ patent, BP9952. If the rubber was heated in molten sulphur at 310–320F for a period of over two hours it ‘turns nearly black and has something the appearance of horn and may be pared with a knife similar to that substance.’ By 1846 he had obtained the first patent for its use, and that was for making moulds for the vulcanisation of ordinary ‘soft’ rubber vulcanisates. In the US Charles Goodyear and his brother, Nelson, were heavily into ebonite, although the first US patent was only granted to Nelson in 1851. In the same year he took out British patent 13542 for the manufacture of ebonite by mixing rubber, 50 phr sulphur, and 50 phr mineral filler, and then heating for between two and six hours at temperatures of around 270 F. In the patent he listed applications such as buttons, door knobs, and inkstands. Between 1851 and 1855 Charles Goodyear took out a further nineteen patents for ebonite, listing its application in the manufacture of a wide range of products. The Great Exhibition of 1851 in London and the Exposition Universelle of 1855 in Paris have previously been referred to, and in both of them Goodyear displayed his range of ebonite articles in a suite of rooms constructed of and furnished with ebonite or ebonite-veneered wood. He even had a special edition of his book Gum elastic printed on rubber pages and bound between elaborately carved ebonite covers, and in it he listed over one hundred
Tears of the Tree 234 different articles which he had already made from the material. He also called it caoutchouc whalebone and caoutchouc ivory. His description of his ebonites was as follows: The hardest of these compounds resembles marble; that which is less hard, ivory and buck-horn; that is still softer, buffalo-horn and whalebone; while they possess, in general, more durable properties than any of the substances above named, except marble, and they are even more substantial than that, in some respects; because, in all degrees of hardness, they have a great degree of toughness or tenacity, and the property of retaining the shape into which they have been moulded and heated.
Hancock was less passionate about ebonite, but still appreciated it and manufactured a wide range of products from it. The hard vulcanised rubber has been applied to many useful purposes to which this patent has contributed. Combs, knife and other handles, ornamental panels for carriages and furniture, stop-cocks, tubing, pump-barrels, pistons and valves for use in chemical works, &c. &c., –these are capable of being turned in the lathe, and to have screws cut on them in the same manner as is practised with wood, ivory or metal. I have also had some flutes made of it, the colour is a jet black, and it polishes like ebony; the notes or sounds are equal to the best flutes, whilst they are said to be produced with greater ease by the performer. I furnished the material to the flute maker without instruction, and he made it in his ordinary practice. . . . We have supplied it by the ton for the use of comb-makers, who like it, not only because it makes a good saleable article, but because they can have it in large sheets of the thickness they require, and make much less waste than when using such small pieces as are produced in horn, tortoise-shell, &c. The turner, the engraver, the comb-maker, and most other artists and mechanics, have only to apply their ordinary means, tools, and skill as to wood, ivory, metal, and other substances. It is also a fair substitute for whalebone and walking-sticks, and also more delicate articles, as bracelets, gold and silver mountings, pens,
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235
and penholders, picture-frames; and one may go from these to the contrary extreme, and if it were economical, or in any way advantageous to do so, it would make good houses, ships, wagons, and carts, and almost everything where wood is now employed, which I only mention to show the universality of its application, and in general, by the ordinary means practised in the different departments of Art.
Due to its ease of fabrication and its usefulness in a pre-synthetic-plastics age, demand was high. In the UK Chas. Macintosh and Co. had already manufactured articles for the 1851 Exhibition and continued to do so. The India Rubber, Gutta Percha and Telegraph Works moved into this field in 1860, and in 1861 the Scottish Vulcanite Company became the first British company to be formed solely for the purpose of manufacturing ebonite articles. In the US there was similar activity, with several firms making ebonite products in the early 1850s. One of these was Poppenhusen and Koenig, which was formed in 1852 after Conrad Poppenhusen split with his long-term partner, Adolph Meyer, with whom he had been manufacturing combs and corset stays from a diminishing supply of whalebone. Soon after, Mayer returned to his native Hamburg to found Harburger-GummiKamm-Co in 1856, which manufactured ebonite combs. Apart from ‘domestic’ uses, ebonite was in great demand from industry as an inert and electrically-insulating material. Ebonite pumps had been manufactured in the 1860s, but by 1900 it was almost possible to construct a complete chemical manufacturing plant from ebonite. It was also used in telegraph equipment and later radio equipment, as well as the ubiquitous car battery case which survived virtually until modern times. With the advent of synthetic rubbers coupled with the shortage of the natural material, it was inevitable that synthetic ebonites should be made, and the first of these was made from methyl
236
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(a)
(e)
(b)
(f)
(c)
(g)
(d)
Fig. 12.4 Ebonite articles: (a) a jumble of necklace chains, (b) pendants, (c) buttons and brooches, (d) detail of one brooch (top right in (c)), (e) fountain pens, (f ) flute, (g) pipe bowl, (h) revolver hand grips, (i) brooch, (j) Queen Victoria Jubilee medal, (k) ornamental comb, (l) combs, (m) medicine holders, and (n) cigarette lighter.
Padding or Performance Enhancer? (h)
(l)
(i) (m)
(j)
(n) (k)
Fig. 12.4 (Continued).
237
Tears of the Tree 238 rubber during the First World War when the Germans used it to make accumulator cases. By the end of the Second World War it was estimated that 90% of American ebonite was synthetic, whilst the British figure was nearer 60%. Some idea of the ‘domestic’ product range is shown in Fig. 12.4.
13 The Rot sets in The discovery of vulcanisation in the middle of the nineteenth century was believed to be rubber’s Holy Grail and, whilst in part this was true, it gave rise to other problems which had to be resolved. Now that vulcanised rubber products could be manufactured, it was more obvious than ever that there still remained forces at work which rendered them useless after a relatively short period of time. Hancock, in his classic book on rubber technology, published in 1857, repeated the observation which he had first made in about 1826: ‘The injurious effects of the sun’s rays upon thin films of rubber we discovered and provided against before much damage accrued.’ He had obviously realised at a very early stage in his ‘rubber career’ that sunlight induced degradation of rubber, but in spite of his assertion it was certainly not ‘provided against’. What Hancock did not realise was that lightcatalysed degradation was oxidation and it was left to Spiller, in 1865, to show that degraded rubber had, in fact, been oxidised. The song in Fig. 13.2 found in a magazine from the 1860s, but without any suggestion as to how old it might be, certainly indicates that there was complete awareness in the trade of the problems with proofed cloth. The story of the understanding of rubber degradation and the ways of limiting it, albeit only to a certain extent, is very much one of the twentieth century. In 1895 Henriques discovered that,
240
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Fig. 13.1 Examples of degraded rubber fabric.
if a piece of natural rubber was extracted with acetone and then vulcanised, then it showed a much greater tendency to oxidise than did the rubber if it had not been extracted. Conversely, in 1931 Dufraisse and Drisch showed that, if the extract from a sample of natural rubber was recombined with a previously extracted rubber, then much of the protection returned. Their conclusion was that there must be some naturally-occurring chemical present in the ‘raw’ rubber which acted as an antioxidant. At the turn of the twentieth century it was discovered that amines and amine-based materials offered considerable protection against oxidative degradation, but it took until about 1930 for purpose-designed amine-based antioxidants and antiozonants to become commercially available. However, these materials had one considerable handicap; although they were pale straw in colour when first synthesised, they soon oxidised to various shades of blue, purple, and black. Whilst this might not be too important in a black vulcanisate such as a car tyre or an
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241
The Proofer’s Song Sung to the tune: ‘the Vicar of Bray’ 1 When cloth was proofed with pure Para, There then was little danger, And very little chance for a Big debit ‘gainst a stranger. But now and then a faulty mix Would happen midst our toil, sir, So every time, when in a fix, I blamed it on the ‘Oil,’ sir. Chorus: This view so strong I’ll hold in song, Until my dying day, sir, That whensoe’er the proofing’s wrong Somebody else may pay, sir. 2 When rubber substitute was made To help adulteration, I ne’er by word or glance betrayed ‘Oil’ caused deterioration. My mix became infallible As any Pope of Rome, sir, And if it did prove variable I swore ‘twas caused by ‘Chrome,’ sir. Chorus:
3 Whene’er my risky proof gives way, I rise in righteous wrath, sir, And hold, ‘gainst what the weavers say, The fault is in the ‘Cloth,’ sir; And when my strongest argument But very weakly halts, sir, Another reason I invent, And blame ‘the ‘Copper Salts,’ sir. Chorus: 4 Should fuller knowledge prove too strong For this, my just contention, I’ll never own the proofing’s wrong, But trust to my invention’ For when engaged in a dispute, Perhaps you may not know, sir, I change my argument to suit Whichever wind may blow, sir. Final Chorus: That this is right I’ll strive and fight, Until my dying day, sir, And sing my song, though proof goes wrong, The proofer should not pay, sir.
Fig. 13.2 ‘The Proofer’s Song’.
industrial bearing, it was certainly of little use in the many lightcoloured products, such as rubber thread or strip, coming to the market at that time for use in the clothing industry. Today paraphenylenediamines (PPDs) are regularly used and function as both antiozonants and antioxidants. As antiozonants they operate by reacting more readily than the rubber double bonds with any ozone present at the surface of the article. In so
Tears of the Tree 242 doing they build up a protective film which, as it thickens by migration and further reaction of the migrated antiozonant, eventually provides an impermeable barrier to the gas. Any damage to the skin, such as cracking, is repaired by further migration. As well as discolouring the product, and since part of the mechanism by which these antidegradants operate is by migrating to the product surface, they could then further migrate into any material in contact with the protected rubber and then oxidise in their new environment, producing a dark stain. There are many different paraphenylenediamines and one of the main reasons for a manufacturer to select a particular one for a specific product is its solubility and rate of migration in the polymer system being protected. Since this is so obviously a crucial factor in the long-term protection of a product, it is not unusual for several such materials to be added and so give a broad spectrum or extended lifetime of protection. However, because they so readily stain, their use must obviously be selective. It took a further generation (the late 1940s/early 1950s) for the ‘non-staining’ phenolic antioxidants to be developed and brought to the market, even though Murphy had patented the use of phenol and cresol as antioxidants as early as 1870. Everything is relative, and it was soon realised that, whilst these antioxidants were certainly ‘non-staining’ compared with many of the aminebased materials, it was not true to say that they would remain colourless, or that they might not discolour materials in contact with them. Indeed, some gave very pronounced yellowing to fabric in contact with them. Phenolic antidegradants are not considered antiozonants, only antioxidants. When oxygen attacks a rubber molecule various sequential and competing chemical reactions occur which may result in polymer chain breakage and/or the insertion of further crosslinks. The phenols offer an alternative path in the chain reaction sequence which stops it
The Rot sets in
243 progressing. It is essential to realise that they do not stop the initiation step, so their effect is, at best, to slow down the oxidative breakdown, perhaps by up to five times. They do not form a protective ‘skin’ if oxidised on the rubber surface; indeed, because of their mode of operation they need to be intimately dispersed or dissolved in the rubber to function. However, conventional diffusion theory predicts that, if two materials are in contact with one another and one contains a dissolved substance not present in the second, then that substance will migrate from one to the other, and it is often the case that light-coloured rubber vulcanisates are in contact with fabrics. The discolouration of ‘white’ vulcanisates may sometimes be related to poor-quality or inappropriate grades of white filler or brightener (although this hardly ever results in the staining of contact fabrics). A common source of organic discolouration or staining is the reaction between dithiocarbamate cure residues and trace amounts of copper, or to a lesser extent iron. There are, however, certain cases where some yellowing has been traced to phenolic antioxidants. This was initially put down to impurities in the chemicals, but it soon became apparent that it was oxidative degradation of the antioxidant itself that was producing a derivative which was coloured yellow. Obviously, staining could be due to either migration of that yellow derivative or migration of the unoxidised antioxidant followed by its oxidation to the coloured product. The yellowing effect was found to be stronger in urban or industrial environments than rural ones, suggesting that the extent of oxidation was being increased by the oxides of nitrogen, which are nowadays major atmospheric pollutants, produced as by-products of the high-temperature combustion of fuels by motor vehicles, industrial boilers, etc. These oxides of nitrogen (collectively known as NOXs) have the potential to cause
Tears of the Tree 244 colouration by the introduction of a nitro group into the antioxidant, or by oxidising it to a quinone. Both of these new groups are known as chromophores, and the more chromophoric groups a compound contains then the deeper its colour will be. Groups such as the phenolic OH are called auxochromes and these will deepen, although not cause, any colouration. Unfortunately, these processes cannot be described without recourse to chemical terms, but the following illustrations may make them comprehensible. It was shown that four distinct reactions were responsible for their discolouration and it is a sad fact that none of this chemistry relates to the way in which a phenolic antioxidant is supposed to function: para-oxidation, ortho-nitration, para-nitration, oxidation of the phenol group. Furthermore, each molecule which is oxidised by one of these mechanisms is one molecule which is lost to the protective system. The yellowing reactions are therefore undesirable reactions which should be prevented for good commercial and longevity reasons, as well as preventing the discolouration of the product or material in contact with it. A comparison of the structures of those antioxidants which discoloured with those which did not showed that oxidation or nitration of the para- position only occurred when there was no meta- substitution, and here it is important to remember that the yellow derivatives are not only the nitrated phenols, which obviously require the presence of NOXs, but also the quinones, which do not, these being simple oxidation products. Of the antioxidants which did not discolour, all were either para- substituted or, if they had no para- group, they were meta- substituted, with the substituent groups being large enough
The Rot sets in (a)
ORTHO
META
OH
(b) (CH3)3C
OH
6
2 ORTHO
5
3
245 C(CH3)3
2, 6 di-t. butylphenol (ethyl antioxidant 701)
META
C(CH3)3
4
C(CH3)3
PARA
O
O C(CH3)3
C(CH3)3
4,4'-bis-(2,6-di-t. butyl cyclohexadiene-1-one)
OH (CH3)3C
C(CH3)3 NO2
2,6-di-t. butyl-4-nitrophenol
Fig. 13.3 (a) Substitution positions on a phenolic ring. This is the basic phenolic group. At each point (2–6) there is a C–H group and the substitution positions are named. (b) Possible atmospheric degradation routes illustrated by formulae. A commercial phenolic antioxidant (top) has alkyl groups at the ortho- positions which ‘block’ it from further attack. The left-hand product shows two molecules oxidised and joined together to give a quinone. The right-hand product has been nitrated in the para- position.
to prevent the introduction of the relatively large nitro group into the para- or 4-position, or preventing oxidation to the quinone. Even if we have a well-protected vulcanisate there are many ways in which it may degrade during its service life. The factors which influence this life fall into two basic categories which can be called ‘product characteristics’ and ‘ageing processes’. There is no chance of retrospectively influencing the product characteristics since these describe the product as it was made and precipitate such questions as: 1. Which elastomer was used? 2. Is the product filled or not and, if so, is it black, coloured, or white?
Tears of the Tree 246 3. What is the vulcanising system? 4. What is the protective system? 5. Is it properly designed and manufactured or has it built-in stresses? 6. What is its size and shape? Once the product exists, the simple but informative illustration in Fig. 13.4 shows that there are a number of potential routes by which damage can occur. Abrasion and external chemical attack may be unavoidable during service life, but should not occur on storage. Temperature, sunlight, and stresses can all accelerate or initiate the chemical changes which are waiting to happen. These changes, collectively known as ‘ageing’, involve three distinct and potentially co-synchronous mechanistic routes for
Mechanicooxidative fatigue O
Ozone cracking 3
2
Heat and oxidation O2
Sunlight crazing
Crosslink reversion
S
SS
O2
Abrasion Chemical attack
O2
Compression set at high temperature
Fig. 13.4 Pictorial illustration of possible routes to rubber degradation— the ‘imps’.
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most (sulphur) vulcanisates. These can be described as: 1. continuing sulphur chemistry, 2. shelf ageing, and 3. atmospheric ageing. Continuing sulphur chemistry has been described earlier and is particularly important in vulcanised products which are resisting a distorting force. This will include anything from a stretched rubber band to a flat tyre. One of the features of vulcanisate ageing is ‘set’, and this is caused by the polysulphidic bonds which form the chemical crosslinks between polymer chains breaking and the loose ends reattaching to either their original partner or another loose end (crosslink reversion). If the vulcanisate is under a distorting force, then, as the bond breaks, the elasticity of the polymer chain causes it to relax against the force, so that the bond will join with another loose sulphur chain end further down the elastomer chain. The result is a slow ‘slippage’ of the vulcanisate which cannot be reversed, although it can be minimised by the appropriate choice of crosslinking agents. Shelf ageing is basically oxidative degradation. The detailed chemistry of oxidative degradation is, even now, not completely resolved. However, in a simplistic form, the oxidation of a sulphur-vulcanised polyolefin such as natural rubber proceeds via at least one chain reaction sequence which introduces C–C and C–O–O–C crosslinks between polymer chains as well as C–O–O–C rings within the same polymer chain, and another set of chain reactions between oxygen and the sulphur atoms of the crosslinks or pendent groups. These two sequences of chain reactions can result in both chain scission and the formation of additional crosslinks. The reactions between sulphur and oxygen can also, eventually, lead to the formation of sulphuric acid, a particular problem with ebonites. There is therefore a large
Tears of the Tree 248 range of both sequential and competing reactions, and the ones which predominate will depend on factors such as the composition of the vulcanisate as well as the influences of heat, light, the atmosphere, and metal catalysis. In heat ageing we are balancing the rate of reaction of oxygen with the elastomer against the rate of diffusion of the oxygen into the bulk material. If the temperature is relatively low, it has been postulated that for an unprotected vulcanisate diffusion predominates, and therefore there is slow oxidation throughout the product. However, as the temperature rises, the rate of oxidation increases much more than the rate of diffusion, so substantial oxidation occurs on the surface and an oxidised (hard) surface skin is formed. As oxidation continues the chain breakdown may become more significant and the hard surface then softens and turns sticky. To complicate matters further, under certain conditions this order can be reversed and an initially sticky degraded surface can harden with further oxidation. The mechanism for light-catalysed oxidative degradation requires the energy of ultraviolet (UV) light to be sufficient to break a C–H bond and generate a radical species, which can then react with oxygen to initiate the same chain reaction sequences as those which occur in direct oxidation. Two types of protective agents are available to combat this, namely the ultraviolet absorbers (UVAs) and the hindered amine light stabilisers (HALS). The UVAs competes with the olefinic double bonds for the available energy and dissipate it harmlessly. It is important to remember that the absorption of light follows Beer’s law, so even if one has a UVA present it would give no real protection to a material less than about 0.5 mm thick. The HALS operate by a different mechanism which is still not completely resolved, but is believed to be a radical trap. It thus operates throughout the UV-transparent sample and the HALS are often used in conjunction with a UVA.
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249 Light-catalysed oxidation can result in an inelastic skin which, as it thickens, cracks in random directions and produces a pattern known as ‘crazing’. In the early stages, in thin sheets, the effect has been called ‘light stiffening’, whilst in highly-filled articles the degradation can result in complete loss of the resinified elastomer and one ends up with what has been described as a ‘chalking’ effect. This has given rise to comments about ‘blooming’ inorganic fillers, which is mechanistically impossible. Due to the lightabsorbing properties of black-filled materials, this effect is not normally seen in them. In many real-life vulcanisates of reasonable bulk under ambient conditions, it seems that the ingress of oxygen is limited and, apart from the surface few millimetres or so, the bulk rubber remains in excellent condition over many decades. Atmospheric ageing differs from shelf ageing in that it is characterised by the attack of ozone on the rubber. It is essential to be aware that this is not just another form of oxygen-induced degradation as the mechanism is quite different. Simple bimolecular ozonolysis of the rubber olefinic double bond being followed by immediate cleavage gives two carbonyl end groups. If the rubber is under any sort of stress this will result in ‘atmospheric cracking’, in which the cracks are perpendicular to the direction of elongation. As early as 1931 it was shown that ‘ozone cracking’ was different from ‘light ageing’ and actually took place more readily at night than during the day. The effect of trace metal contaminants such as copper, chromium, and iron in any of the compounding chemicals is inevitably to accelerate the rate of degradation, although the change in rate cannot be predicted as it depends on many factors, not least the chemical state of the metal. As long ago as 1931, Semon, Sloan, and Craig reviewed proposals, published over the previous fifty years, to give protection to objects made without added antidegradants by the topical
Tears of the Tree 250 application of protective agents dissolved in a solvent. Under their accelerated ageing tests some benefit was found, but the protection was not long-term. Today, this may still be advocated, using a solvent for the antidegradant which will swell the rubber and thus facilitate diffusion into its bulk. This may not damage a new vulcanisate, although why one should wish to treat it in this way is not obvious, but, if the object is not vulcanised, or is degraded so that the surface is structurally weak, then the rubber will either dissolve, or swell to such an extent that the surface will be severely damaged. Damage could also be done to the bulk rubber vulcanisate, particularly since the solvent will be extracting whatever it can from within the bulk rubber whilst the antidegradant is diffusing in. If one really wishes to use this method then a non-solvent for the rubber must be a better choice, as this will still allow diffusion into the bulk rubber without appreciably swelling and damaging the surface structure. It might still, however, extract previously added materials from the article to its subsequent detriment. If the choice is not to diffuse protective chemicals into the unprotected rubber then there is still the option of adding a protective surface coating, and such a skin can be built up by topical application, provided that the limitations to crack repair and surface finish are appreciated. One barrier technique has been well established for many years; this is the coating of the article with an oil lacquer which is then vulcanised. A possible modern equivalent procedure might be the use of a pre-vulcanised butyl latex spray-coat, since butyl rubber is relatively impermeable to air. There is one particular area of degradation which needs a separate discussion and that is the area of blooming, which, as a visually obvious time-related event, is generally classified with degradation, although it need not have any actual connection.
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251 Everybody knows what they mean by the word bloom, occasionally called ‘frosting’, but it is quite apparent from investigations carried out over the last thirty years that these words include a wide variety of very different effects. These can be divided conveniently into: 1. 2. 3. 4.
true blooms, modified blooms, pseudo blooms, and surface contamination.
It is also worth including here a consideration of stains and discolourations, as these are sometimes confused with blooms. The mechanism of true bloom formation is simple in broad theoretical outline, but was only described by Nah and Thomas in 1980. The substance which blooms must have a limited but appreciable solubility in the rubber, and must be present in excess of that solubility. This excess will exist as discrete particles throughout the mass of the rubber, either because it has never dissolved or because, having dissolved at some higher temperature, it has crystallised-out on cooling. These discrete particles can easily be seen in sections cut from pure gum rubber and examined under the microscope. As the substance crystallises it will be appreciated that micro regions of local strain will be set up in the rubber which is displaced by the formation of the crystal. This strain results in pressure on the crystal and its solubility is thereby increased. At the exposed surface of the product, crystals of the material can form without distortion of the rubber and the solubility will be unaffected. This means that the solubility of the substance will be slightly less at the surface, and there will therefore be a concentration gradient of dissolved material which will cause diffusion from the inside towards the surface. This will persist until all the material crystallised in the bulk has dissolved
Tears of the Tree 252 under the influence of pressure and diffused outwards. The magnitude of the increased solubility due to pressure will, of course, be minute, as also will the concentration gradient within the rubber, but large forces are not necessary. Water will flow down the gentlest of slopes! Free residual cure sulphur is probably the most common substance to give a true bloom, and in a vulcanised product such a bloom is due to the product not being adequately vulcanised (see Fig. 13.5). This, in itself, could result from a number of factors,
Fig. 13.5 Sulphur bloom seen under a microscope.
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253 and the relationship between the time and temperature of cure should be factors to be considered first of all. Indeed, it will be recalled that it was a bloom of sulphur on one of Goodyear’s vulcanisates which convinced Hancock to persevere with his experiments using it to obtain vulcanised products. In spite of this, it was not until 1950 that Galloway and Foxton described a quick test for identifying a bloom of free sulphur. Zinc dithiocarbamates are also known to give blooms, and of the three common ones, the dimethyl-, diethyl-, and dibutyldithiocarbamates, it is the middle one which shows the most rapid and, over a period of time, the densest bloom. The order of solubility is ZDMC
Tears of the Tree 254 Certain chemicals present within the matrix of a rubber vulcanisate react, either by design or incidentally, with constituents of the environment, and this results in a significantly different mechanism of blooming. As has already been described, typical examples are the paraphenylenediamine (PPD) antiozonants, which protect the rubber by reacting with ozone to form an insoluble protective skin on the surface. More PPD migrates to the surface to compensate for that consumed, and the process of migration will continue until the skin of oxidised PPD prevents further ozone penetration. An equal concentration of PPD will then be established throughout the bulk of the rubber whilst it waits to carry out any repairs to the film. Paraphenylenediamines may also bloom by the ‘true bloom’ mechanism and it is therefore important that they are only added at levels below their solubility. Although this is usually the case when a formulation is originally devised, subsequent modifications without a full realisation of their significance have been known to take formulations ‘over the limit’. Zinc salts of carboxylic acids (in particular, zinc stearate) constitute further examples of both true and modified blooms. Zinc stearate has a known solubility in cis-polyisoprene of about 0.3%, and thus the addition of 1 phr stearic acid and 2–5 phr zinc oxide should inevitably produce a bloom. However, it is also known that the solubility of zinc stearate is greatly increased when it complexes with amines and, since these are usually present as accelerator decomposition products, or in raw natural rubber, the problem is less acute than it would appear at first glance. In moist atmospheres, a bloom of zinc stearate reacts with water vapour to produce ‘basic zinc stearate’ which forms on the surface as a solid layer, visually indistinguishable from a bloom, and this is completely insoluble in the rubber. A true zinc stearate bloom can be dissolved back into the rubber by heating, but this is not the case with the basic salt.
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255 On a surprisingly large number of occasions the matt finish on an initially smooth shiny surface is not due to the blooming of a particular compound or to deposition of a contaminant, but to the degradation of the rubber surface itself. The pitted surface which may develop from oxidative degradation results in sufficient light scattering to give the impression of a bloom. In the particular example shown in Fig. 13.6 the oxidative degradation follows a pattern which suggests that there are internal stresses
Fig. 13.6 Stress-induced surface oxidation showing loss of the smooth surface.
Tears of the Tree 256 within the vulcanisate which are tearing the weakened surface. This is particularly significant in view of comments by Moakes in 1950, who claimed to have seen ‘blooms’ of calcium and zinc carbonate. There is no doubt that, because of their complete insolubility, these inorganic materials cannot migrate and therefore cannot bloom. This latter phenomenon is often observed in lightly-coloured articles and is due to the even more extensive degradation of rubber surrounding the filler particles, which results in the exposure of these particles in a ‘crater’ of rubber. It is always difficult to decide by visual inspection whether a surface deposit is a bloom or contamination. For instance, one of the most common causes of surface contamination is silicone oil which has been used to coat the mould in which the rubber article is to be formed. Not only does this impart an oily film to the surface, but it also gives a base to which dirt and dusting powders may adhere. The washing of rubber products also gives rise to contamination if rinsing is inadequate, and both inorganic salts and organic materials have found their way onto the surface of rubber articles by this route. Haze is defined as a cloudy appearance within the bulk of a transparent article, and from a visual inspection it is often difficult to distinguish between it and a bloom. This will result from the presence of insoluble particles or, in the case of liquids, micelles or droplets having a different refractive index from rubber and so able to cause light scattering. One of the commonest causes of this is the use of zinc oxide either of the wrong grade or in excessive amounts, and this problem can be eliminated by the use of special fine-particle grades at levels not exceeding 1 phr. Although the terms ‘staining’ and ‘discolouration’ tend to be used interchangeably, it is probably better to consider discolouration as applying to the rubber article itself, and staining as
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257 describing the effect produced on a material in contact with the compounded or cured rubber. In the vast majority of cases these effects are brought about by free sulphur or dithiocarbamates in contact with copper, as both copper sulphide and copper dithiocarbamate are very dark in colour and give a visible stain even at the single-figure parts-per-million level. Trace metals such as iron and copper in the rubber itself or in fillers such as clays or calcium carbonate (whiting) can also give rise to discolouration, as too can the use of zinc oxide with an over-high level of lead. Perhaps one of the hardest problems is in defining at what level these elements become effective discolourants. Although this chapter draws together a wide range of effects, some of which can only be deduced from a fall-off in product performance whilst others will be visually obvious, there are good reasons for treating them together. With the exception of the often misunderstood deliberate skin formation of waxes and antiozonants, they all signify the approaching end of service life for the particular product. Even those effects which are only visually offensive will tend to get the object discarded in a domestic environment, although industry might well wait for more positive indications of a potentially catastrophic physical failure before replacing it.
14 Death and Destruction Whatever is done to extend the life of a vulcanised rubber article, it will eventually fail to give satisfactory service or meet minimum legal requirements and will have to be disposed of. In today’s world there is an explicit presumption in favour of ‘recycling’, although historically ‘dumping’ would be a better word. In 1996 the American artist, Meg Belichick, was so distressed at the state of the Gowanus Canal, which she saw every day as she travelled between her home and studio in Brooklyn, that she handcrafted one hundred books with lead covers and letterpressprinted rubber pages interspersed between historical photographs to chart its history from a pristine state to a badly polluted waterway. The lead and rubber were symbolic of the pollutants. This is not the only time that rubber, waste, and art have joined three-in-a-bed. In the mid-nineteenth century the journalist and author, Nathan D. Urner, produced the ‘weepie’ shown in Fig. 14.1. Many countries, but by no means all, have now legislated against the dumping seen by Meg Belichick, whilst in those countries the ‘little ash girl’ no longer exists. If dumping is banned then recycling becomes part of the life and death cycle, but what does this mean for rubber? The word recycling implies a closed loop as, for instance, in the case of glass bottles or metal cans which are used, scrapped, collected, and then simply recycled to produce more new bottles
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The Rubber Doll A Christmas Story in Verse What is this that, at last, my weary task In dirt and ashes all day unearths? A doll of rubber, just such a one As brings the glimpse of a Christmas gone Amongst pleasant people and happy hearths!
This doll recalled it again just now, This Rubber relic of playthings past! And but yesterday, when outwearied quite, I paused as I marked a lady bright Sweep to her coach from a toyshop vast.
The nails are worn from my fingers sore, And naught but a little ash girl am I. The policemen bid me move along, Swinging their arms and amongst the throng I shrink to the kerbs with downcast eyes.
Her arms were loaded with Christmas things, For darlings at home I doubted not: As she rustled by, how I dropped my look! How mean my rags when her kindly look Fell upon me as she passed the spot!
The little children, prettily dressed, Draw back, or mockingly troop around; And from the gay shop-windows are looks of distrust, As from barrel to barrel of rubbish and dust I scrape and delve for what may be found.
Her brow was noble and her eyes were sweet: And with tenfold force in my foolish brain That broken vision glowed fresh and clear Of one who, perchance, held me dear In that midst of the past, now blank and vain.
The brutes who reared me in this black toil, And whose den I seek at the day’s dark close, Are quick to seize what my wanderings win, And, after their orgies of beer and gin, Have nothing fore but oaths and blows.
And I sobbed aloud, but I scraped away Till my sack was heavy as it could be; Then hurried back to that noisome den, With its smells and oaths, like a prison— pen, And the cuffs and kicks ever ready for me.
I call her mother and him my sire, But a thrill in my blood throbs back the lie, For a fragment of broken memory slips Back, back from a dream of loving lips To my baby mouth; and a vision flits by
But I dreamed that night a delicious dream, That has since made light in my darkened heart: I will dream it again, I know, to-night, With this Rubber doll in my arms held tight— So tight it never shall from me part!
Of a pleasant home in a garden old, And a dark-eyed lady whose voice was sweet, And shaggy dog and a painted boat On the waves of a shining river afloat, And I on the shore, in wee bare feet.
‘Tis a shining dream of a garden old, With a painted boat in a river’s flow, And all in a world far better than this, With a mother’s love and a mother’s kiss, Which this little ash-girl at last shall know. Nathan D. Urner 1839–1893
Fig. 14.1 ‘The Rubber Doll, A Christmas Story in Verse’.
Tears of the Tree 260 and cans. This can hardly apply to vulcanised rubber which cannot be ‘melted down’ and reshaped whilst retaining its original properties. A broader definition is required. Perhaps the simplest one would be based on a desire to find ways in which rubber products can be used or treated at the end of their design life so that they provide some cost benefit to the community and reduce the environmental damage that results from dumping in landfill sites. Indeed, many countries have regulations in place which already control or ban this practice. Worldwide, around seventy per cent of all elastomers are used in the manufacture of tyres and vehicle-related components. This is the area which is concentrated on today, but the history of recycling rubber is almost as old as the industry itself. One of Hancock’s first forays into rubber was to slice rubber bottles imported from Amazonia to make elastic bands, and, whilst this might not quite fit the definition in that the bottles had not reached ‘the end of their design life’, the other criteria were met. Whilst ‘recycle’ is a modern word, the reuse of scrap vulcanised rubber by grinding it to a powder or crumb and incorporating it as a filler in a new product was first patented by Goodyear in 1853. Indeed, some low-quality products were made just by shaping the crumb in a heated mould under pressure. This would imply that there was a considerable amount of free sulphur in many ‘vulcanised’ products at that time and, perhaps, reflects on their overall quality. The market for rubber crumb was restricted and raw rubber was expensive, so efforts continued to devise ways of chemically devulcanising scrap rubber. In fact, the first patent to achieve this had been taken out a few years earlier, in 1846, by Alexander Parkes, although his work seems to have been largely ignored. However, the numerous patents taken out between 1853 and 1878 reflected the ongoing interest in the field. In 1881 Mitchell
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261 set up the first company in the US dedicated to the manufacture of reclaimed rubber, his raw material being that stalwart of the American rubber industry—the rubber overshoe or galoshes. His process could best be described as chemically ‘vicious’! The rubber was treated with sulphuric or hydrochloric acid for several hours at high temperature and pressure before being neutralised, washed, dried, and ground. It was then passed over magnets to remove iron, mixed with a softener, devulcanised with steam for twenty hours, and then sheeted on a mill. This became known as the ‘acid process’ and the reclaimed rubber was reputed to produce some excellent products. The company became well established and one can only assume that with raw rubber and silver costing about the same, pound for pound, it was cost effective. The advent of the motor tyre containing fibre reinforcement required a different reclaim procedure, and the ‘alkali process’ was patented by Marks and Price at the turn of the twentieth century to deal with this. Ground tyre (or other) scrap was treated with caustic soda solution at high temperature for twenty hours and then further separated and sorted. This reclaimed rubber was also reputed to have good physical properties and, being slightly alkali even after washing and drying, gave the added bonus of acting as a vulcanisation accelerator. In the early part of the twentieth century the demand for rubber was such that up to fifty per cent of the rubber used was reclaim, but the industry had to evolve as the inclusion of carbon black and accelerators made the rubber much less amenable to the existing processes. Developments between the two world wars were mainly concerned with high-temperature treatment in either an inert gas or in air/oxygen which was controlled to fragment the elastomer chains, as well as the sulphur–sulphur bonds, until the resulting molecules were short enough to be
Tears of the Tree 262 processed in the same way as the original masticated rubber. Reclaim from car and truck tyres continued to be a significant business through to the 1960s, but demand fell when cheap oil, the feedstock for the synthetic rubber industry, became available, and the advent of steel-belted radial tyres made the reclaiming process more difficult and time-consuming and therefore, inevitably, more expensive. By the early 1990s demand had fallen to single figure percentages, but things changed when environmentalists became concerned about the number of tyres being dumped in landfill sites. Figures for scrapped tyres are notoriously difficult to obtain, but a ‘typical’ car tyre contains about twenty pounds of natural and synthetic rubbers, a bus tyre perhaps one hundred and twenty pounds, and the biggest truck tyre over five thousand pounds, weighing in with a total weight of over five tons. About nine million tons of natural and synthetic rubbers are reputed to be used in tyres each year, representing over fifteen million tons of tyre. This will be an overestimate of the scrap tyre market as there is an expanding demand for all types of vehicles and tread rubber is obviously lost during service. Nevertheless, figures in excess of one billion scrap tyres per year are normally quoted. In America alone there are estimated to be between two and three billion scrap tyres in landfill or other ‘storage’ sites. The recycling of non-tyre rubbers is fraught with problems. A significant amount is used in the medical and related health industries and this has the potential to be contaminated in a number of ways. There is little realistic choice but to burn this with other hospital waste. Fluorocarbons, chlorine-containing elastomers such as plasticised PVC and polychloroprene (neoprene), as well as nitrogen-containing elastomers such as the nitrile rubbers have their own problems. They first have to be identified and their service history evaluated so that the possibility
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263 of contamination can be considered. They must then be disposed of by specialist processes so that toxic gases are not released to the atmosphere by their destruction. It is worth noting that, apart from non-car uses, these elastomers may well be found in today’s motor vehicles as hoses, gaskets, boots, etc. Nevertheless, these are all relatively small components and there is little prospect of recovering any useful elastomeric materials from them. The move towards the use of thermoplastic elastomers in the manufacture of vehicle components such as door and window seals, boots, and mats offers a compensatory ‘bright side’ to this picture. Tyres, however, remain the major disposal problem. Landfill with whole tyres carries a number of environmental problems. They render the land unstable as they have a tendency to ‘heave’ or work their way to the surface and they can damage the landfill linings, potentially allowing contamination of local groundwater or surface water by substances which have been leached from the landfill. Stored out of landfill, they can burn. There have been a number of scrap tyre fires which have burned for weeks, months, or even years, and these have caused considerable environmental damage. Much of the rubber degrades to an oil by pyrolysis, that is, thermal degradation in the absence of an adequate supply of air, and this oil, being less dense than water, will float away on the firefighters’ water to contaminate local supplies, or even spread the fire if conventional firefighting techniques are used. Many fires are just left to burn. In the EU the disposal of whole tyres in landfill sites was banned after 2003 and shredded tyres will also be banned by 2006. This leaves some form of recycling, rather than simple disposal, as the only way forward. Whatever is done, there has to be a market for large quantities of ‘end product’ at a satisfactory price—profitable for the recycler and cheaper than any performance-equivalent material for the
Tears of the Tree 264 purchaser. This could be direct or through some form of government subsidy but, in the end, it must be financially worthwhile for any company to invest capital to build a plant and to carry out the recycling. There is also a further factor to consider. The energy requirements for whatever form of recycling is chosen must be justified against those of other methods of disposal. It is no good recycling something if the recycling and remanufacturing processes require more energy in total than is needed both to create the same product from virgin elastomer and to dispose of the old one. The concept of ‘total energy audit’ for any product from its birth to final disposal is becoming a vital commercial tool. In truth, the recycler is limited in what he can do with his scrap tyre. He can reuse the tyre as a tyre or find a new non-tyre use for it. He can also mechanically fragment the tyre or more seriously degrade it. All these options are currently being used. Some are established whilst others have yet to get past the research stage and be proved cost-effective. There are three primary ways in which tyres can be reused as tyres and the first is by retreading or recapping a good quality carcass or casing. In the developed world, where radial car tyres have virtually eliminated cross-ply tyres, passenger car tyre retreading is almost non-existent. This is partly due to the perceived poor image of these tyres as they are always speedrestricted, and this does not gel well with the ever-increasing performance of passenger cars. There is also a simple economic fact; new tyres can be bought from eastern Europe more cheaply than retreads can be manufactured in the West. Furthermore, the lightweight design of modern car radial tyres makes them unsuitable for retreading. If they were designed and built more strongly so that they could be retreaded, then there would be a penalty in performance and comfort terms which would add yet more energy and cost implications into the overall energy equation.
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265 In the truck and aircraft tyre market, retreading is common and it is not unusual for up to six retreads to be placed on a truck crossply casing, although it is usually one or two on a radial-ply casing. As already suggested, the word ‘retread’ has a poor image, and in the case of aircraft tyres it has been changed to the more acceptable ‘recapping’. There is a ‘spin-off’ from the retreading trade as the used casings first need to have their old treads removed by buffing, and these buffings find a ready use in the manufacture of playground pads and other child-friendly equipment since there is no possibility that they could be contaminated with metal shards. Tyres can also be reused by the simple process of resale! It has been estimated that up to fifty per cent of US tyres are scrapped before they are halfway through their design life, probably by owners changing complete sets or pairs when only one has been damaged. A significant number of these are resold in the US and more are exported to less-developed countries. A parallel position exists in Europe, whilst there are also regulations which govern the minimum tread depth allowed before the tyre becomes illegal. Again, exporting to less-developed countries for both road use and for fitting on agricultural trailers and carts is a wellestablished business. There is a downside to this exporting trade as the tyres will eventually be scrapped in a country where the facilities and environmental pressures for disposal compare with those of the developed world a generation or more ago. The third and final way of reusing a tyre applies to bus and truck tyres, which are specifically built and marked on the sidewall for re-grooving. It is then permitted to hand-cut a new tread pattern when the old one has been substantially worn away, although this is a job for the professional, not a person at home with a sharp knife. There are many ways in which old tyres can be used and one familiar one is as an energy absorber at the barriers of all types of
Tears of the Tree 266 motor racing circuits, from go-carts upwards. They often have a similar application as fenders (see Fig. 14.2(a)) for preventing small boats from damaging piers (or vice versa) and can be spread over piles of manure or silage in farmyards to hold down the covering tarpaulins. A slightly more exotic use is shown in Fig. 14.2(b). This shows a row of planters, made by turning truck tyres inside out. In Thailand similarly-worked tyres are used as rubbish bins in many towns. Perhaps the most unusual application on record is shown in the photograph in Fig. 14.3, taken in Mexico, where a squatter has created a level foundation for his house on a pre-existing slope by building a base from old tyres filled with sand. A similar use is found in the poorer parts of South Africa, where discarded tyres are filled with mud or dirt and used as actual building blocks of houses. Whether such a structure would receive planning approval in the UK or EU is a moot point! Scrap tyres have also been used to create artificial reefs off the coasts of Australia, Israel, and America, where they have the potential to provide a structure on which coral can grow. They have also been used for crab and lobster farming and for coastal stabilisation. These are just a few examples and, no doubt, many more uses have been, and will continue to be, developed. The third approach a recycler can use is to mechanically fragment the tyre, and here the products will depend on the degree of ‘fragmentation’. The picture in Fig. 14.4 is of a complete suite of furniture which was made in the Far East and certainly represents a degree of lateral thinking! It is arguable whether this should fall within the category of a complete tyre or a fragmented one but, if neither, it certainly forms a link. One of the other uses to which large pieces of cut tyre tread have been put is to make native ‘shoe soles’, which are tied to the feet with binder twine.
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(a)
(b)
Fig. 14.2 Old tyres used as (a) boat fenders in Crete, and (b) planters in Malaysia.
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Fig. 14.3 A Mexican house using old tyres filled with soil to create a level stable (?) foundation.
At greater levels of fragmentation, rubber chips and crumb are currently the staple of the recycling industry. The tyres are first shredded and chopped to give chunks about two inches in size which are then ground to a crumb. Two major types of grinding procedures are currently in use, namely ambient and cryogenic. In the ambient process the chunks enter the granulator or crackermill at room temperature but heat up rapidly as they are torn apart. The crumb size is determined by meshes which fit in the machines and which can be changed to meet specific demands. These particles tend to have a rough texture from their torn faces. In the cryogenic process the chunks are cooled with liquid nitrogen and then reduced in size using a
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Fig.14.4 ‘Tyred’ furniture.
hammermill. The final product from this process is shiny and has clean fracture surfaces. In both systems any metal (steel) is removed with magnets and any fibre by aspiration. The cryogenic product tends to be less contaminated because of the clean fracturing between the rubber and steel, and has obviously been less exposed to the possibility of thermal degradation. Both of these processes give crumb around one-quarter of an inch in size, but, if finer materials are required, they can be manufactured by a secondary process which usually involves wet grinding. The uses for crumb rubber are legion but can be divided into four basic categories: 1. automotive-related products, 2. athletic and recreational products,
Tears of the Tree 270 3. moulded and bonded products, and 4. rubberised asphalt or bitumen. It is common practice to add crumb at between three and five per cent to cross-ply truck tyres, and it seems possible that this figure will increase somewhat if test results show that the tyres meet performance and safety standards. There is virtually no crumb added to radial tyres as it results in a lower resistance to flex cracking and abrasion, both of which shorten the life of a tyre. Indeed, some automotive regulations specifically exclude the use of any sort of ground rubber or reclaim in radial tyres. Some acceptable applications include agricultural and trailer bumpers, as well as mudflaps and splash guards. Inside the vehicle, door step mats and brake pedal covers are prime candidates, although care has to be taken not to use crumb with a high volatiles content as this may cause ‘fogging’ of the vehicle’s windows in hot conditions. Again, the maximum extent of permissible ‘fogging’ is governed in specifications issued by some vehicle manufacturers. In athletic and recreational applications the most common uses for unbonded material or loose mulch are for top dressings in children’s playgrounds, where it has been found to be a safer and more cost-effective option than wood bark, and equestrian training or display rings. It has also been found that a layer of rubber crumb, laid under turf, can give considerable advantages in terms of drainage whilst minimising soil compaction, both of which improve the longevity of the surface. This application has been used both in playing fields and the greens of golf courses. Its general use as a top dressing in landscaping has also been advocated. Bonded materials fall into two distinct types. The first of these is the incorporation of a small amount of moisture-curing urethane rubber as a binder into the crumb, which is then poured,
Death and Destruction
271 spread, rolled, and the urethane left to cure. This provides the type of loose textured material used on athletics tracks, again as a base in children’s play areas, and for temporary matting in numerous applications such as where a horse racetrack crosses a road. The second category requires the incorporation of high levels of crumb into an unvulcanied mix, which is then moulded to give a product. Applications include low-speed solid tyres, speed control humps, mats of all sorts, and interlocking rubber tiles. Rubberised asphalt or bitumen has been an area of interest at least since the 1930s and it has the potential to absorb large quantities of rubber scrap. Experiments have been carried out using latex, as well as both raw and vulcanised natural rubber added as either a powder or crumb. The viability of using some synthetics has also been examined. There is now plenty of evidence that the incorporation of rubber tyre crumb extends the longevity of highways when a one- to three-inch layer of rubberised bitumen is used to resurface it. It certainly adds to the cost of laying the surface but in the long term the process is costeffective. Unfortunately, too many roads are resurfaced from short-term funding and this is probably the biggest area of tyre disposal where government intervention could be useful. For instance, the US introduced legislation which would have required those states which had federally-financed resurfacing projects to insist that at least five per cent were surfaced with rubberised bitumen in 1994, rising by five per cent per annum to 1997. Pressure from individual states over the extra costs and from the bitumen suppliers over reduced material sales prevented it from ever being implemented. Nevertheless, many individual states are now demanding its use in attempts to clear their scrap tyre dumps. The incentive is certainly there; current research shows that crumb rubber may be used either as part of the asphalt binder to give ‘asphalt rubber’ or as an aggregate substitution to
Tears of the Tree 272 give ‘rubber-modified asphalt concrete’. There are two processes used to incorporate the crumb into asphalt. The wet process incorporates the crumb into the asphalt mix with a liquid, such as kerosene, to serve as a blender, whilst the dry process blends crumb directly into the asphalt mix. In the US the Federal Highway Administration has been promoting crumb rubber in asphalt paving and points out that one mile of a two-lane road with a three-inch-thick layer uses 1600 tyres in asphalt rubber and 8000–12 000 tyres in rubber-modified asphalt concrete. India is also actively implementing this technology, as are a number of other countries such as New Zealand and Australia, but the EU seems disinterested. The final option to consider for dealing with a scrap tyre is to degrade it to such an extent that it no longer physically exists as a vulcanised rubber matrix. The easiest way to do this is to burn it. This appears to be the current method of choice as it is the largest single way of disposing of scrap tyres, either whole or as chunks, in both the EU and US. A popular location for this is the cement industry since the residual ash can be incorporated into the product, and thus there is no secondary waste to be disposed of. Germany disposes of some ten per cent of its waste tyres by this route, whilst Japan, with its meagre indigenous fuel resources, is another advocate of the process. Other energy-intensive applications such as paper mills and metal foundries may also use this scrap which, pound for pound, has a heating value greater than coal and is certainly easier and cheaper to obtain. It has also been claimed that burning a mix of coal and tyre scrap is environmentally better than burning coal by itself. There are a number of other programmes of research in the area of polymer destruction being carried out today, but none has yet reached commercial maturity. One such approach is controlled thermal degradation by pyrolysis or polymer fragmentation to
Death and Destruction
273 oils and gases by heat in the absence of oxygen. This enables the carbon black, zinc oxide, and steel to be recovered, whilst the oils and gases can be either sold or recycled within the unit as fuel. The furnace design is crucial in these applications to optimise the heat output and to trap the environmentally damaging gases containing sulphur, and possibly chlorine, but this is wellestablished technology in the oil industry and in practice causes no problems other than an increase in costs. One factor which must be considered in all ‘total polymer destruction’ processes is that the most appropriate use of the recovered carbon black would be to recycle it back into new tyres. In an earlier chapter the criteria identifying a satisfactory black were discussed and it is essential that the black structure or its reinforcing properties are not reduced by the pyrolysis process. Although research into true devulcanisation was virtually abandoned in the 1960s, new processes are now being investigated. These include the use of microwaves or ultrasonics, as well as bacterial and chemical attack to break the sulphur–sulphur bonds and thus produce a remouldable rubber. These are currently giving rise to different levels of optimism, but at all times it is necessary to remember that the process must be cost- and energy-effective. As has been noted earlier, in ecological terms the effectiveness of any recycling policy can only be quantified if it first takes into account the energy requirements to produce the raw materials, to deliver them to the factory, process them, and distribute the final product. It must then look at the energy requirements in service, recycling (including collecting and delivery to the recycle unit), remanufacturing, and ultimate disposal. However much the ardent ecologist might argue, ecological concerns are not the only criteria by which life should be judged. Up to twenty per cent of rubber from a tyre will be lost from that tyre by abrasive wear
Tears of the Tree 274 during its lifetime. This gets washed down the drains, into rivers, and eventually out to sea. It causes some ecologists concern. They accept that these minute fragments cannot be trapped and therefore want tyre wear to be reduced. This can be done, but the inevitable consequence is a lower skid resistance, more accidents, and, even just in energy terms, more wrecked cars and people to be looked after. Speed bumps and road ‘nips’ may arguably save lives and injuries, but the energy cost is more wear and tear on vehicle components and a higher fuel consumption. The obvious difference between natural rubber and its two direct competitors, butadiene rubber (BR) and styrene butadiene rubber (SBR), is that the first is a natural product whilst the others are synthetic, manufactured from that ever-diminishing asset— oil. The energy requirements to produce these elastomers and to transport them to a western manufacturing facility were calculated in the mid-1990s and, although they may have changed somewhat in the last decade, they will still be realistic on a comparative basis. They are vastly different, with natural rubber requiring some sixteen gigajoules (GJ) per ton, BR requiring, one hundred and eight GJ/ton, and SBR requiring, one hundred and thirty GJ/ton. Natural rubber has a small processing penalty when manufacturing takes place in temperate regions as it must be kept in a warm store to prevent it from crystallising. It is also a little more energy-demanding than the synthetics during processing, with a total representative mixing-cycle energy requirement having been estimated at about twenty GJ/ton. On that basis the energy requirements to obtain the raw material, transport it to the manufacturing facility, and manufacture a product from natural rubber are only about one-third of those of its competitors. The story does not end there. Whilst BR and SBR consume oil, natural rubber produces timber, and rubber wood is now a
Death and Destruction
275 valuable commercial product in its own right. Given a typical replanting cycle of thirty years, Hevea plantations can produce a considerable volume of timber in a relatively short time. Tropical rain forests are being destroyed at an ever-increasing rate but are required as sinks for carbon dioxide. It has been estimated that the global Hevea biomass in the mid-1990s was capable of fixing ninety million tons of carbon per annum. The amount of BR and SBR produced today is very similar to that of natural rubber, and the global output of natural rubber could easily be increased by a factor of two or more in a very few years. Unfortunately, the one great problem facing the rubber tree owner is that of tapping the trees. The large rubber plantations have been in decline for a number of years as the value of the product has fallen relative to other crops and the smallholders are drifting away from a rural existence towards an urban life.
Fig. 14.5 A Malaysian rubber plantation (or factory?) in 1996.
Tears of the Tree 276 Interestingly, in 2003 the acreage under rubber in Malaysia fell but rubber output increased; the price rose and this encouraged smallholders to tap more trees. It would be extremely simplistic to say that natural rubber could, or even should, replace its synthetic ‘equivalents’, but the grounds for moving in that direction will become more valid as time goes by. In the extreme there is an argument for considering whether the tropical Hevea plantations should be viewed in a completely new light—as a carbon dioxide fixing factory for the sustained production of timber and for the synthesis of a fuel (rubber) which has a few years of otherwise useful life as a vulcanised product before completing the carbon cycle. The life of one product may be over but the life of natural rubber will continue!
15 Timeline Any chronology must be both subjective and selective. This can be no more true than in the case of ‘rubber’, which is now known to have been in use for over 3500 years. Those who have used it have been primitive natives, lost civilisations, and those developing the most sophisticated instruments and equipment of today. Just two areas of application illustrate this breadth of applicability. The same material that is used to make delicate medical devices such as surgeons’ gloves and condoms is also used in the treads of supersonic aircraft tyres. This time chart below shows just some of those events which changed the course of history, together with those which provided just one small step forward (or, some might argue, occasionally backward) for mankind. Throughout the chart there are data on the production of wild and plantation natural rubber and, eventually, on the synthetics. Original documents inevitably differ considerably in their ‘facts’, so these statistics should only be treated as ‘reasonably indicative’! Also included are significant dates in the histories of many of today’s rubber companies—with an inevitable emphasis on the tyre.
Name
Event
60 million bc
Germany
First millenium bc 1800 bc
Mexico Mexico
Rubber-producing plants in existence in Europe (see 1924). Ball courts/figurines holding balls. Beginnings of the Mokaya culture. The Mokaya are believed to be the forerunners of the Olmec and Maya cultures. Mokoya means ‘corn people’. Oldest known ball court of the Mokaya/Olmecs at Paso de la Amada, Mexico. The word ‘Olmec’ means ‘rubber people’. Claimed to have seen natives playing with balls which bounced high in the air. They came from Lydia. Balls, dipped feet to make shoes, coated fabrics, etc. Gulf of Mexico. Ball courts and rubber objects at Chichen Itza—now in Peabody Museum, Harvard University. First European recorded to have seen rubber balls, but second-hand observation—not recorded by Columbus himself. Sees a version of the ball game being played at the court of Montezuma. Began writing Apologetica historia de las Indias (published 1875!) in which he mentions rubber balls and claims that Columbus brought one to Seville. Returned to Spain with two teams of ball players (some say this is what confused la Casas).
Mokaya/Olmec
Mexico
Herodotus
Fourth century bc
Zanzibar
Aztecs/Maya Toltec–Maya
Sixth century (and earlier?) Tenth century
Mexico and Central America Yucatan
Columbus
1493
Haiti
H. Cortez
1519
Mexico
Bartolome de la Casas
1523
Spain
H. Cortez
1528
Spain
Tears of the Tree
Place
278
Mokaya
Date
1530 1536 1536
Spain Spain Spain
1549 Mid-sixteenth century
Mexico Guatemala
F. Hernandez
1570–1577
Mexico
R. Hakluyt
1587
UK
A. de Herrera Tordesillas M. Lok Torquemada
1601
Spain
1612 1615
UK Mexico
Fr A. Vieria
1651
Amazonia
279
First mention of rubber (gummi optima) in print. Describes Aztec religious rites involving rubber. Describes the North American Indian ball game (Batey). Some balls light in weight—blown rubber? Commissioned an Aztec account of Mexican history. An unknown noble wrote down the myths of Mayan creation. Much relates to the twins Hunahpu and Xbalanque (also known as the Sun and Venus) and how they outwitted the ‘Lords of Earth’ by their skill at pok-ta-pok (one name for the ball game). The book is the Popol Vuh. The first person to describe the Mexican rubber tree from first-hand observation. Obtained Spanish version of Mendoza’s document (1549) and Lok translated it into English. It mentions rubber balls being paid as tribute. Writes of Haitian ball game and Mexican trees which can be cut to yield ‘milk’ which gives rubber. Translated Peter of Angiera’s 1530 book into English. Taught how to waterproof cloth and make dipped goods by Indians. Also described the use of rubber distillate as medicine to be taken internally. Jesuits founded Santarem, 500 miles inland on the Amazon/Tapajos confluence—home later of Henry Wickham.
Timeline
Peter of Anghiera De Motolina D’Orviedo y Valdes A. de Mendoza
Place
Event
B. Cobo
1653
Spain
J. Tradescant
1656
UK
Charles Marie de la Condamine
1735–1745
Andes
Franc¸ois Fresneau
1743–1746
French Guiana
F. Fresneau
1747
Cayenne
La Condamine Don Jose´ F. Fresneau
1751 1755 1761
France Portugal France
Herrisant and Macquer J. Banks
1763
France
1768
UK
Associated ‘Cachuc’, which in the Kechua language relates to demon worship and magic, with rubber (liquid obtained from a tree). First appearance of gutta-percha in the UK—called ‘mazer wood’. Gutta-percha is a Malay word. Described how Indians ‘milked’ trees for liquid to waterproof fabrics. The Indians called the tree ‘heva’ and the gum from the liquid ‘cahutschu’. He used the word ‘latex’ to describe the ‘milk’ or sap from the tree. Realised the potential of the material and infected France with enthusiasm for rubber research. The problem was that latex could not be shipped to Europe without ‘going bad’ and solidifying. Discovered the only ‘Hevea braziliensis’ in French Guiana, which led to much confusion! Presented his and Fresneau’s work to Paris Academy of Science. The King of Portugal sent boots to Para´ to be waterproofed. Discovered turpentine, an ideal solvent for rubber. He told Minister Bertan, who ‘leaked’(?) information to two professional scientists, Herrisant and Macquer. Worked and published separately on rubber solvents and obtained perhaps undeserved credit (see 1942). First references to rubber in the UK. Purchased latex(?) in London and sent two rubber balls to John Canton.
Tears of the Tree
Date
280
Name
1768
France
Macquer
1769
France
P. Poivre
1769
Mauritius
E. Nairne
1770
UK
Priestly (of oxygen fame)
1770
UK
M. Vaucasan
1772
France
Magalhaens
1775
France
J. C. A. Theden
1777
Germany
J. Ingenhousz
1779
UK
281
Replaced turpentine with ether and cast strong films which were not sticky. Also made tubing on wax formers and suggested making catheters. Made riding boots for Frederic the Great by multiple-dipping process. First ‘modern’ observation of ‘African’ rubber. Probably the landolphia rubber plant. Started to sell cubes of rubber from his artists’ shop as pencil erasers. Noted that Nairne sold a half-inch cube of material for erasing pencil marks for three shillings. He called it ‘India rubber’, having found from whence it came. Interested in rubber—asked Minister Bertan to write to Fresneau (now in retirement in south-west France) asking for all the information he had on rubber. Perhaps this was the initiation of the modern rubber industry? (Also called ‘Magellan’) ‘discovered’ the same thing five years later. Proposed catheters reinforced with silk-coated spirally-wound wire, then coated with rubber from solution. Wrote of constructing rubber tubing by sticking together freshly-cut surfaces of rubber—much stronger than solution tubing and, without knowing it, the principle which made Hancock’s masticator work (Fresneau was aware of this stickiness but his comments were not published until later).
Timeline
Macquer
Place
Event
A. Juliaans
1780
Netherlands
F. de St Fond J. A. C. Charles
1781 1783
France France
V. Cervantes
1786
Mexico
Roberts and Dight
1790
UK
G. Fabrioni
1791
UK
Gossart
1791
France
S. Peal
1791
UK
Fourcroy J. Watt S. D. de la Vega
1791 1794 1798
France UK Mexico
First thesis (or book) solely on rubber (University of Utrecht). Concludes that the various Amazonian botanists were writing about more than just one ‘rubber’ tree. He refers to many medical applications including catheters. First mention of rubber coating balloon fabrics. First hydrogen-filled balloon. The fabric was rubber-proofed oiled silk. Wrote of the indigenous Mexican rubber industry and of the ‘Ule tree’ from which the latex came. Noted that acetic acid coagulated the latex to give a clean solid rubber. First patent referring to rubber—solution for treating canvas before oil painting. Wrote of twenty years research with the new solvent ‘naphtha’ and its excellent solvent properties for rubber. Rediscovered Fresneau/Ingenhousz’ processes for building ‘cut’ tubing—added a ‘heat-sealing’ process. Patented waterproofing of many fabrics with rubber solution. Suggested latex could also be used. Stabilised latex with alkali. Developed an instrument for gas inhalation using ‘Gossart’ tubing. Laminated two layers of chamois leather with a latex adhesive to give bags strong enough to transport mercury across the Atlantic.
Tears of the Tree
Date
282
Name
C. Goodyear W. Roxburgh
USA France
1803
France
Fourcroy and Nicholson P. de Beauvais J. Bright
1804
France
1805 1810
West Africa UK
J. Reithoffer Baron P. L. Schilling
1811 1811
Austria Germany
Baron P. L. Schilling J. F. Hummel J. Clark
1812 1813 1813
Germany USA UK
J. Syme
1818
UK
Weisse T. Hancock
1818 1819
UK UK
Charles Goodyear born. May have made ebonite by passing chlorine into a solution of rubber in carbon disulphide. He obtained ‘a white inelastic mass’. Probably the first ‘rubber factory’ (to make elastic bands) built near Paris. Suggested alkali-stabilised latex could be shipped to Europe.
283
Classified a rubber-producing vine. Founded John Bright & Bros to supply cloth and fabric for rubber belting manufacturers. Started a rubber goods factory in Vienna. Probably the first rubber-insulated cable used for underwater telegraphy experiments. He used a similar cable to explode mines underwater. Gum elastic varnish—first US patent which mentions rubber. Patent for making inflatable articles from rubber interior-coated fabrics—beds, cushions, etc. Proposed a substance from coal tar be used as a rubber solvent—cheap and readily available with the new gas lighting. Manufactured curved catheters with excellent surface finishes. First started using rubber solutions to coat fabrics and manufactured articles—gloves, etc.
Timeline
1800 1801
Place
Event
T. Hancock
1820
UK
T. Hancock
1820
UK
1820
USA
1821
UK
1821 1821 By 1823 1823
UK UK USA UK
1823
UK
First patent for dry rubber; cut strips for elasticating clothes, braces, etc. Opened a factory in London which became ‘James Lyne Hancock’. Invented his ‘pickling’ machine which enabled dry rubber to be worked into a ‘dough’. Actually a masticator. Dipped shoes appeared in the USA, made in South America, exported to Paris—gilded, ‘fashioned’, and returned to America. Bertrams Ltd established. Made machinery for linoleum, paper, and rubber manufacture. Pickling machine (masticator) now horse-powered. Used naptha as rubber solvent. Direct imports from Brazil. Realised that, if fabric was coated with rubber solution then had another layer of fabric applied to rubber, the three-layer sandwich was waterproof and not sticky–‘mackintosh’. Founded Chas. Macintosh and Co.
1824
UK
1825
UK
T. Hancock J. Syme C. Macintosh
C. Macintosh, H. Hornby, and J. Birley T. Hancock
Obtained the first authenticated sample of latex in the UK and proposed using it to saturate fibres and compress to make ‘artificial leather’. First rubber belting from these materials. Pitch/rubber solution; provided sheets for coating ships’ bottoms, etc.
Tears of the Tree
Date
284
Name
UK USA USA UK
H. C. Lacy
1826 1827 1827 1828
UK UK UK UK
J. N. Reithofer
1828
Austria
E. M. Chaffee
1828 1820–1830
USA USA
T. Hancock
1830 1830
UK UK
E. F. Leuchs
1831
Germany
E. M. Chaffee A. Barbier and N. E. Daubre´e
1831 1832
USA France
T. Hancock
Thomas’s brother began work on rubber/fabric hoses. First native rubber shoes sold in the US. Established empirical formula of natural rubber as C5H8. Agreement with Macintosh to make rubberised fabrics and garments at Macintosh’s factory in Manchester. Patent for carriage springs made of rubber blocks. First recorded use of rubber hoses against a fire (in London). Patented rubber solution spreading machine. Water beds containing warm water used in Wales to assist miners with hypothermia. Patented rubber thread wrapped with fabrics to give elastic-woven webs. Roxbury India Rubber Co. founded (first US rubber company). On average, some 500 000 pairs of rubber overshoes per annum had been imported from Para´. Use of latex for dresses and ornaments. Sent a teacher to Brazil to show the natives the best way of collecting and preserving latex. Sulphur and hot molten rubber gave a ‘coal-like’ mass—probably ebonite. Rubber/turpentine/lampblack paint to waterproof leather. Founded company named after themselves. Eventually became Michelin et Cie.
285
1825 1825 1826 1826
Timeline
J. Hancock T. C. Wales M. Faraday T. Hancock
Place
Event
F. Lu¨ddersdorf
1832
Germany
Dr Arnott
1832
UK
E. M. Chaffee
1832
USA
W. Montgomerie
1832
Singapore
W. H. Barnard
1833
UK
N. Ruggles and S. D. Breed T. Hancock and C. Macintosh A. Jones E. M. Chaffee
1833
USA
Rubber and a little sulphur in solution—heated to give better ageing and reduced stickiness—the first vulcanisate? Claimed to have invented the water bed and gives details of manufacture and advantages. Roxbury India Rubber Co. began manufacture of rubber footwear in the US. First encountered gutta-percha, used by the natives to make hatchet handles. Patent for ‘cracking’ rubber to produce ‘caoutchoucine’ and suggested its use as a rubber solvent. Patent for sticking shoe and boot soles on with rubber.
1834
UK
Hancock became Director of Chas D. Macintosh and Co.
1834 1834–1836
UK USA
J. Thurston C. Goodyear
1835 1834
UK USA
Proposed making ‘carpets’ of canvas, wallpaper, and rubber. Invented the two-roll, two-speed mill which could be heated/cooled. Invented the three (and more) roll mill for calendering rubber ‘dough’. Both are still the basic procedures and designs of today. Introduced rubber billiard table cushions. Became intrigued by rubber—some say obsessed after seeing rubber goods in New York store of the Roxbury India Rubber Co.
Tears of the Tree
Date
286
Name
1836 1836 1837
France UK UK
T. Hancock
1837
UK
T. Hancock
By 1837 1838
USA UK
C. Goodyear and N. Hayward N. Hayward
1838
USA
1838
USA
K. MacMillan
1839 1839
UK USA
C. Goodyear
1839
USA
C. Goodyear
1839
USA
Pyrolytically decomposed rubber. Used rubber solutions for binding books. Wrote that Mr Pickwick’s frown vanished like the marks of a blacklead pencil beneath the influence of India rubber. Invented the spreader, the standard coating machine of today. At last forced to release details of his ‘pickling’ machine or masticator. Economic crisis. Rubber bubble bursts. Made latex thread using a spiral groove cut in a cylinder. No applications or interest shown. The two meet.
287
Patented ‘solarisation’ process whereby rubber films treated with solution of sulphur in turpentine and exposed to sunlight develop a ‘superior surface’. Patent USP1090 granted Feb. 1839. Invented the first pedal-driven bicycle. Rubber-manufacturing industry in the US finished, but 5 000 000 pairs of unvulcanised shoes per annum still imported from Brazil. Purchased rights to Hayward’s ‘solarisation’ process and began experimenting with rubber/sulphur mixes. Left a mix of rubber, sulphur, and white lead on a hot stove and he recognised that the resulting material was ‘cured’ of all its defects. It no longer softened on heating or hardened on cooling, and it had lost its stickiness.
Timeline
A. Bouchardat W. Hancock C. Dickens
Name
Event
1841
USA
J. A. Fanshawe
1841
UK
S. Moulton
1842
UK/USA
W. Brockedon
1842
UK
1842
UK
J. Robinson
1842
UK
T. Hancock
1842/1843
UK
W. Montgomerie
1843
UK
C. Goodyear T. Hancock
1843 1843
USA UK
T. Hancock
1843
UK
First commercial vulcanised material—rubber thread for ‘shirred’ cloth. Patent for a masticator, with specific mention of the addition of sulphur and lead oxide (as an opaque filler). An Englishman in America, he came to the UK as Goodyear’s agent, with samples of his vulcanised rubber to negotiate a deal with interested UK parties. Showed Hancock some of Goodyear’s cured rubber and proposed the term ‘vulcanisation’ for the process of its manufacture. The UK began to import rubber from Singapore (from Ficus elasticus and Urceola elastica). Joseph Robinson & Co. founded. Rubber-manufacturing equipment. Identified sulphur in a piece of Goodyear’s cured rubber. Could not duplicate cure as did not know about white lead, but effected cure with rubber/molten sulphur. Introduced gutta-percha to Europe. First use was for knife handles. Then golf balls, etc. First US vulcanisation patent applied for. Produced ‘hard rubber’ (ebonite/vulcanite) by prolonged treatment of rubber with molten sulphur. In November he obtained UK provisional patent for vulcanising rubber.
Tears of the Tree
Place
288
Date
A. Parkes C. Goodyear
1843 1844
UK UK
T. Forster A. Turner
1844 1844
UK UK
J. Thurston J. Patterson W. Siemans R. W. Thompson
1845 1845 1845 1845
UK UK UK UK
Lagre´ne´e C. Hancock and H. Bewley T. Hancock
1845 1845
France UK
1846
UK
C. H. Stearn A. Parkes
1846 1846
USA UK
W. T. G. Morton
1846
USA
Over 100 rubber and rubber equipment manufacturing companies formed in this period. Some historically interesting ones are in the timeline. Used carbon disulphide as solvent for rubber. In February UK patent application refused but US patent granted. Suggested rubber-moulded dolls and toys. Used vulcanised wrapped rubber thread to make webbing for ‘elastic-sided’ boots. Introduced vulcanised rubber billiard table cushions. First gutta-percha golf ball made in Scotland. Suggested gutta-percha as telegraph wire insulant. Patented the pneumatic tyre but no vehicles suitable to make it a commercial success! Brought gutta-percha from China. The Gutta Percha Company formed. Manufactured the first solid rubber tyre. Used for steam-powered vehicles. Made a part-ebonite plate to treat cleft palates. ‘Cold-cure’ process discovered. Using sulphur chloride, initially in solution but then in vapour phase (see 1876). This initiated the ‘dipped goods (thin film)’ industry. Advent of anaesthetics with rubber components of apparatus.
289
UK
Timeline
1843–1900
Place
Event
C. Hancock
1846
UK
Alexander, Cabriol, and Duclos W. Brockedon
1846
UK
1847 1847
UK USA
J. G. Ingram W. H. Barlow and T. Forster J. J. Craven C. C. Page
1847 1847
UK UK
Patented a vulcanised sponge rubber—suggested use in cushions. First gutta-percha patent—for a laminate consisting of three layers: gutta–fabric–gutta. Used ammonium carbonate as blowing agent—still used today. Vulcanised rubber shoes and overshoes manufactured again—many for UK market. Began manufacture of vulcanised rubber balloons. Patent for the making of telegraph cables with gutta-percha.
1847 1847
UK USA
S. Moulton
1848
UK
1848
UK
1848 1849
Finland UK
1849
UK
W. Burke
Insulated undersea cables with gutta-percha. Noted the close similarity of the thermal decomposition products of natural rubber and gutta-percha. Moulton founded his rubber goods company at Bradford-on-Avon. Byrne India Rubber Co. founded; later sold to Dunlop Pneumatic Tyre Co. Nokian Tyres founded. Used golden antimony sulphide instead of sulphur to produce red thread (20% of thread market by 1914). First recorded use of gutta-percha as a telegraph cable insulant (in London).
Tears of the Tree
Date
290
Name
UK
T. L. Wilson
1850
West Africa
J. Brett and J. W. Brett
1850
UK
J. Brett C. Goodyear N. Goodyear
1851 1851 1851 1851 1851
UK USA USA UK USA
1853
Amazonia
S. W. Silver
1852
UK
W. R. Forster and T. J. Williams
1852
UK
1853 1853 1853 1853 1854
Amazonia UK UK USA UK
W. Johnson
W. Johnson
Founded R & J Dick Ltd, gutta-percha and balata manufacturers. Drew attention of rubber traders to the rubber-producing vines and their possible commercial value. Failed in first attempt to lay gutta-percha-insulated cable from Dover to Calais. Second attempt failed but then completed. Proposed ebonite as a bonding layer—rubber to metal. Charles’s brother, Nelson, patented manufacture of ebonite. Great Exhibition in London full of rubber and ebonite articles. Vulcanised rubber shoes being manufactured at a rate of over 5 000 000 pairs per annum. The first ‘serious’ rubber traders moved up the Amazon with the coming of steamers. Founded what was to become the India Rubber, Gutta Percha and Telegraph Works in London. Founded Forster & Williams (submarine and India rubber manufacturers) which joined with C. E. Heinke & Co. in 1902. Three tons of rubber exported. Suggested ammonia as suitable stabiliser for latex. First imports of latex to UK. Rubber sole with leather edging (to sew to uppers) appeared. Patented the use of a press for vulcanising shaped products.
291
1850
Timeline
R. and J. Dick
Place
Event
C. Goodyear
1855
USA
1855
France
J. H. Johnson
1855
UK
C. Goodyear Junior H. Lee Norris and S. T. Parmelee
1855 1856
USA Scotland
T. Hancock
1856 1857
Germany UK
C. W. Field
1858
USA/UK
A. F. E. Robert G. A. Engelhard and H. H. Day W. Hooper
1858 1859
UK UK
Discusses various ‘fillers’ or bulking agents—including lampblack and various earths. Exposition Universelle in Paris. As with London (1851), full of rubber and ebonite products. Goodyear’s book Gum elastic present, printed on rubber pages and with carved ebonite covers. Patented ebonite components in spinning/weaving machinery and also proposed ebonite-coated metal components. Patented use of ebonite for dental plates. UK manufacture of vulcanised rubber shoes began in Scotland to avoid Hancock’s English patent. The North British Rubber Co. founded. Harburger-Gummi-Kamm-Co formed to make ebonite combs. Published his Narrative, with much practical information on rubber products and their manufacture. First transatlantic cable (insulated/coated with gutta-percha) laid by the cable ship The Faraday. Manufactured the first hollow rubber dolls. First prepared chlorinated rubber.
1859 1859
UK UK
1860
USSR
Introduced the first rubber-insulated/coated cables. New Liverpool Rubber Co. founded—later to become Dunlop Rubber Co. Rubber footwear manufactured in St Petersburg.
Tears of the Tree
Date
292
Name
UK
W. Clissold J. T. Pitman
1860 1860 1860 1860 1861
UK UK Brazil World UK
F. Hofmann F. Shaw J. Quinn
1861 1861 1862
UK UK
J. Leighton S. C. Barnum Sanderson
1862 1862 1862 1862
USA USA UK UK
J. K. Wright
1864
USA
Nokian Tyres N. Hayward
1865 1865
Finland USA
Scottish Vulcanite Co.
Decomposed natural rubber and isolated isoprene (C5H8). Gave it that name. Rubberised ‘V’ belting patented. Used steam-heated platens in his vulcanising press. Rubber prices at all time high—cost more than silver. Worldwide production of natural rubber around 1500 tons. First British company dedicated to ebonite—The Scottish Vulcanite Co.—formed. Later joined with North British Rubber Co. Showed that degraded gutta-percha had oxidised. Developed the first screw extruder for rubber production. Founded Brookland Rubber Co., later Leyland and Birmingham Rubber Co. Invented the ubiquitous rubber stamp. Dental dam introduced. Proposed brass as a bonding interface between steel and rubber. The invention of the inflatable rubber bladder (and the pump to inflate it) gave the modern football. Carbon black first produced commercially to use with rubber vulcanisates. The Finnish tyre company founded. Died. Tombstone in Colchester, CT describes him as the inventor of ‘hard rubber’ (ebonite).
293
1860
Timeline
G. Williams
Place
Event
C. W. Field
1866
Atlantic
Dom Pedro II
1867
Amazonia
R. W. Thomson
1867
UK
1868
USA
M. Berthellot
1869
France
B. F. Goodrich Murphy CKGP Co.
1870 1870 1871
USA USA Germany
A. Stephen and F. Pegler J. Collins G. B. Pirelli H. Wickham
1871
Atlantic cable laid from Heart’s Content (Newfoundland) to Valentia (Ireland) by the Great Eastern. Opened the Amazon and its tributaries to foreign trade. Ocean liners could now reach as far as Iquitos (2300 miles from the Atlantic coast). Patented first commercial solid vulcanised tyres for steam engines and bicycles. A shoe was produced with a vulcanised rubber sole fused to a canvas upper. Reputedly known as the ‘felonies’ and also ‘brothel creepers’, they must have been very quiet! In the UK they were eventually called plimsolls by Philip Lace (1876). Polymerised styrene—not an elastomer but mentioned here because of its importance in SBR, SBS, etc. Founded rubber factory in Akron. Recognised ‘oxidation’ as cause of deterioration in rubber. Continental Kautschuk und Gutta Percha Co. established in Hanover. Founded Northern Rubber Co.
1872 1872 1873 1875
UK Italy Brazil World
Commissioned to report on rubber in Brazil. Forms G. B. Pirelli & Co., UK-registered company, in 1909. Commissioned by Kew to collect seeds of ‘Hevea braziliensis’. Worldwide production of natural rubber approached 10 000 tons.
Tears of the Tree
Date
294
Name
France
H. Wickham R. Cross King Leopold II
1876 1876 1876 1876
Brazil Singapore Brazil Belgium
H. M. Stanley
1877
R. Cross or H. Wickham? W. Curie
1877
Belgium Congo Singapore
1877 1878 1877–1878
UK West Africa Ceara
W. Abbott
1878
UK
G. Bouchardat I. Adams
1879 1881
France USA
V. Kreussler and E. Budde
1881
Suggested that isoprene was the primary unit of rubber and obtained a ‘rubber’ by heating it with fuming hydrochloric acid. The first synthetic rubber? Dispatched about 70 000 Hevea seeds to Kew; 2397 germinated. Fifty seedlings arrived from Kew. Died due to neglect. Brought Hevea seedlings to Kew. Leopold II of Belgium opened an International African Conference which gave birth to the Association Internationale Africaine (AIA). He completed his three-year journey from the east coast of Africa to the west coast, following the River Congo. Twenty-two, seedlings arrived and survived. Ridley said, ‘Basis of virtually all Asian trees today.’ Patented rubber golf balls. Rubber exports totalled 220 tons. A great drought; half a million died, the rest fled—many to the Amazon basin to provide the tappers so desperately needed. Invented the sulphur chloride vapour cure process for curing thin films—balloons, medical gloves, etc. Repolymerised isoprene to ‘rubber’. Developed electrolytic deposition of copper or silver to provide interface between metal and rubber. First patent for barrier protection of rubber vulcanisates.
295
1875
Timeline
G. Bouchardet
Place
Event
H. Trimen H. Low C. A. Burghardt
1882 1883 1883
Sri Lanka Malaysia
F. Shaw
1883
UK
G. Daimler
1884
Germany
P. Lacollonge C. Macintosh L. E. Waterman
1884 1884 1884 1884
France UK USA USA
1884 1885 1885 1885
UK Germany UK UK
1885
Belgium Congo UK
Sent trial samples of rubber to the UK for evaluation. Arguably sent the first Malaysian rubber to the UK. Noted that copper accelerated degradation of vulcanised rubber. Founded Francis Shaw (rubber engineers). He started as an engineer with C. Macintosh. Produced a lightweight four-stroke petrol engine which would fit in a ‘horseless carriage’. Patented ebonite tank linings to hold corrosive liquids. Invented a ‘cushion tyre’ for bicycles. Patented ebonite fountain pens. The ‘State’ of the Congo which Leopold had created and controlled through a series of confusingly-named companies was recognised by the USA. The India Rubber Journal (IRJ) first published. Manufactured the first vehicle designed as a motor car. Proposed gutta-percha for power transmission belting. Founded Avon Rubber. Tyre division taken over by Coopers in 1997. Exported first African wild rubber.
Daimler and Benz R. Dick E. G. W. Browne and J. C. Margetson
1886
Southern Rubber Co. founded.
Tears of the Tree
Date
296
Name
Moseley
1887
UK
1887
H. N. Ridley
1888
Singapore
J. B. Dunlop
1888
UK
Michelin H. Du Cros and J. B. Dunlop W. S. Halstead
1889 1889
France UK
1889
USA
1889 1890 1890 1890
USA UK Amazonia Belgium Congo
H. C. Pearson A. Smith
Left Leyland Rubber to start the British Rubber Co. He also left Leyland Rubber to start Iddon Bros Ltd, machinery manufacturers. Took over Botanical Gardens and began a one-man crusade to develop rubber plantations. ‘Reinvented’ the pneumatic tyre, but now bicycles and vehicles were available to use it. Groupe Michelin formed. Launched Pneumatic Tyre Co. Later to form Dunlop Rubber Co. First use of rubber gloves in the operating theatre (made by Goodyear Rubber Co.). Founded the journal India Rubber World in New York. Founded the Scottish India Rubber Co. 20 000 tons exported out of world production of 30 000 tons. 130 tons exported.
297
1887 1887
Timeline
J. Swann J. Iddon
Belgium Congo UK UK
Patented ‘Flexifort’, a tyre cord with 98% warp and 2% weft which eliminated the abrasive degradation problems associated with conventional fabric-reinforced tyres. Used by Dunlop in his 1888 tyres. Nevertheless, fabric reinforcement lasted through to the end of the First World War.) Thirty tons of rubber exported.
Place
Event
W. E. Bartlett
1890
UK
J. K. Korzeniowski
1890
Belgium Congo
J. W. Williams
1890
Belgium Congo
J. G. Araujo, J. C. Arana, and the Suarez brothers
Late 1800s to 1920
Amazonia
Leopold II
1891
Belgium
Edouard and Andre Michelin Leopold II
1891
France
Developed tyre rim designs essentially similar to today’s. The Bartlett Clincher developed. Korzeniowski ( Joseph Conrad) gathered enough experience in six months to write the semi-autobiographical Heart of darkness and An outpost of progress. In an open letter to President Harrison he coined the phrase ‘A crime against humanity’ in describing what was happening in the Congo. The three great overlords, all three specialising in torture, maiming, and murder to amass their millions (Araujo in the ‘Manaus’ region; Suarez, 16 000 000 acres in Bolivia centred at Cachuela Esperanza; Arana, 14 000 000 acres in Colombia and Peru). Arana is the most documented because of the ‘Putumayo atrocities’ (see below). Issued a secret decree banning natives from selling rubber and ivory, and demanding action from his agents to secure them for the State (i.e. himself ). Patented detachable cycle tyre—won the Paris–Brest–Paris race.
1892
Belgium
W. Tilden T. Robins
1892 1892
UK USA
He split the Congo into three, one part for himself, a second for his cronies (and by 1898, 50% for himself ), and a third for Colonel North (financed by Leopold). Synthesised ‘rubber’ from synthetic isoprene. Developed heavy-duty rubber belting for moving iron ore.
Tears of the Tree
Date
298
Name
USA
US Rubber
1892
USA
L. J. McNutt Silvertown Co. G. L. Porter
1892 1893 1894
USA UK UK
G. L. Hille
1894
UK
T. Rowley and H. Grimshaw H. M. Stanley
1895
UK
1895
Tan C. Y. Michelin
1895 1895
Belgium Congo Malaysia France
R. Henriques
1895 1895
Malaysia Germany
Goodrich
1896
USA
B. F. Goodrich made pneumatic cycle tyre with cord construction. US Rubber Co. formed. Later to become Uniroyal and eventually part of Michelin North America Co. Discovered how to make channel black. Manufacturing of cord tyres in the UK. Harborough Rubber Co. specialising in boot and shoe soles, heels, etc. New Eccles Rubber and Cycle Co. launched to make rubber balls. British Recovered Rubber Co. Ltd founded. Possibly the first limited company for reclaiming waste rubber. 200 miles of railway completed from the east coast to Stanley Pool. Five years in the building and several thousand lives. Made the first true commercial plantings of Hevea in Malacca. Introduced the first pneumatic motor car tyre which was fitted to a specially designed Daimler. The car took part in the Paris–Bordeaux–Paris race of that year and finished ninth out of forty-two entrants. First practicable rubber estate. First person to record that solvent extraction of rubber resulted in poorer ageing properties. Introduced the first pneumatic motor car tyre in the US.
299
1892
Timeline
J. F. Palmer
Place
Event
H. J. Doughty H. N. Ridley
1896 1897
UK Malaysia
H. N. Ridley
1897
Malaysia
L. J. McNutt B. W. Richardson
1897 1897
USA UK
W. H. Cox W. McKinley
1897 1897
USA
C. Haskell
1898
USA
Schrader F. Seiberling and C. Seiberling Michelin
1898 1898
USA USA
Patented the first ‘whole tyre’ curing process (Dunlop Rubber Co.). Advocated the Hevea tree above all others for rubber production in Malaysia. Developed and promoted a tapping method very similar to that used today. Gave much improved yields and extended the useful tree life. Commercial production of channel black. Adapted the idea of a rubber-bulbed scent spray to spray anaesthetics—also used by Lister for antiseptics. Patented a machine for making hollow rubber balls. President McKinley proposed rubber cultivation in appropriate US possessions—American ‘rubber gold’ rush. By 1910 planting abandoned and by 1920 virtually nothing left. Patent for golf ball made of a core wound with stretched rubber thread and coated with gutta-percha applied for. Patented the Schrader valve. Goodyear Tyre and Rubber Co. formed.
1898
France
J. Perkins
1899
Malaysia
The ‘Michelin man’ or ‘Bibendum’ appeared for the first time. Conceived by Edouard Michelin, commissioned by Andre Michelin, and drawn by Marius Rossillon (aka O’Galop). Used acid coagulation to make sheets of rubber suitable for drying/smoking and transporting.
Tears of the Tree
Date
300
Name
J. C. Arana
1899 1899
Sri Lanka
1899
UK
By 1900
Michelin J. Kondakov H. Firestone E. D. Morel
1900 1900 1900 1901
Belgium Congo France Germany USA UK
Goodyear and Ford Sir C. Dilkes
1901 1903
USA UK
P. W. Litchfield
1903
US
1903
Timeline
R. Casement
1900 1900
First plantation rubber shipped from Sri Lanka. Started rubber trading in the Putumayo region of north-west Amazonia. The first ‘sterling capital’ company launched for rubber cultivation in Malaysia (the Selangor Rubber Co. Ltd). Ebonite had many uses because of its corrosion resistance, pumps and battery cases being two major industrial applications. World production of natural rubbers approaches 50 000 tons. Set up the British Consular Service in the Congo, travelled in the bush, and reported on the atrocities he had seen. Michelin introduced grooved tyre treads. Synthesised polydimethylbutadiene (methyl rubber). Established Firestone Tyre and Rubber Company. Morel, an employee of the shipping line which was used by Leopold II, became so sickened by what he had discovered that he resigned and set out to destroy him. Goodyear enters motor racing with Henry Ford. Raised E. D. Morel’s findings in the Houses of Parliament and Leopold was savaged by Parliament. Working for the Goodyear Tyre Company, made first tubeless tyre. Tyre sizes standardised to allow interchangeability.
301
Place
Event
H. W. Brett
1903
Malaysia
S. C. Moke
1904
UK
E. D. Morel and R. Casement Goodyear Co. Firestone Co. Continental Michelin R. Ditmar
1904
UK
Harrison & Crosfield got involved in rubber as agents to and shareholders in the Petaling Rubber Estates Syndicate. Discovered the ‘reinforcing’ properties of carbon black in giving extra strength to a vulcanisate. Set up The Congo Reform Society.
1904
USA
1904
EU
1905 1905
UK south-east Asia
1905
UK
E. D. Morel
1906
UK
G. Oenslager
1906
USA
Diamond Rubber Co.
1906
USA
T. W. Miller
1906
USA
Separately developed straight-sided wire-bead tyre to replace the ‘clincher’. Launched ‘flat tread’ tyres. (Continental also launched a patterned tread and a studded anti-skid tyre.) The first appreciation of zinc oxide as a ‘reinforcing’ filler. 2500 tons shipped out of Malaysia and Sri Lanka (world output 56 000 tons). 100 000 acres planted to rubber. By 1915 close to 3 000 000 acres had been planted in this region. Guthries became involved with rubber as agents for Linggi Plantations Ltd. Published his damning indictment of Leopold—‘Red Rubber’ Leopold was in retreat. First chemical to ‘accelerate’ vulcanisation (aniline, then diphenylthiourea (DPU)). Used Oenslager’s accelerators to make tyres and realised they had improved ageing characteristics. Patented the moulded-rubber hot-water bottle.
Tears of the Tree
Date
302
Name
1906 1907
UK UK
J. C. Arana
1907
UK
1908
Belgium
1908
Germany
1909
US
Leopold II
1909
Belgium
F. Hofmann Goodyear Co. Continental Pickles
1909 1909 1909 1910
Germany USA Germany UK
1910
Congo
W. O. Ostwald and W. Ostwald
First practical use of carbon black as a rubber filler. The Rubber Growers’ Association was launched in London by prominent representatives of plantations in Sri Lanka and Malaysia. Peruvian Amazon Co. formed in London, with control of 800 000 acres in the Putumayo region. Government passed an act ‘freeing’ the Congo, and also ‘bought out’ Leopold for £2 000 000 and took over many of his debts (since he had hidden most of his assets). Patented aniline and similar chemicals as antioxidants.
303
After months of rumour The Truth detailed many of Arana’s company’s atrocities. Died with a known estate of some £5 000 000. He had spent millions more and perhaps 10 000 000–15 000 000 natives died to produce 75 000 tons of rubber under his regime. Patents process for making synthetic polyisoprene. Introduced first pneumatic aircraft tyre. Introduced the first dedicated ‘winter tyre’. Suggested that natural rubber might consist of very long chains of isoprene units. Belgian Congo/French Congo and Angola produced about 50% of all African rubber over the first decade of the century.
Timeline
S. C. Mote
Name
Event
1910
World
R. Casement
1910
Bolivia
C. Harries S. V. Lebedev
1910 1910 1910
UK USSR World
Collins
1911 1911
UK Malaysia
Continental
1911
Germany
R. Paredes
1911
Peru
E. Fickendly
1911
Wild rubber production around 85 000 tons (50% Amazonian, 25% African, much of the rest from Mexico) and 11 000 tons of plantation rubber. Enquired on behalf of the UK into the Putumayo atrocities and confirmed them. Prepared cyclised rubber. Polymerised 1,3-butadiene to give a rubbery material (BR). Wild rubber peaks at about 90 000 tons per annum. Plantation rubber (Malaysia/Sri Lanka) passes 10 000 tons per annum. Patented a process for polymerising styrene. Many Chinese immigrants arrive to ease labour shortage in the plantations. Introduced the first pneumatic truck tyre, but little take-up until after the First World War. An investigating judge, he confirmed that the rumours concerning Arana were true and, indeed, the real situation was even worse. Noted that certain phenolics could prevent rubber oxidation—forty years before introduction of ‘phenolic antioxidants’. Government published the Casement papers relating to the Putumayo atrocities.
1912
UK
Tears of the Tree
Place
304
Date
Diamond Rubber Co. and Goodrich Goodyear Ostwald
1912 1913 1912/1913
USA UK UK
1913 1913
UK and Belgium UK
1913/1914
World
1914–1918
Germany
1914 1914
UK UK
1915
USA
Began commercial use of black, to reinforce tyres (now tyres black, not white from zinc oxide). Goodyear built the first US airship. Deduced that rubber degradation was autoxidation. The House of Commons found the UK directors ‘culpably negligent in the ‘‘Putumayo affair’’ ’. The company was wound up, but Arana could not be prosecuted in the UK and continued much as before. It is estimated that between 1900 and 1910 the Putumayo yielded 4000 tons of rubber at a minimum cost of 30 000 native lives. The Belgian courts finished untangling Leopold’s legacy and the Congo Reform Association disbanded. The India Rubber, Gutta Percha and Telegraph Works Co. patented the radial tyre, but never commercialised it. Crossover point! Plantation output of natural rubber exceeds that of wild (circa 55 000/75 000 tons plantation to 66 000/49 000 tons of wild). Methyl rubber was used to make vehicle tyres and also converted to synthetic ‘hard rubber’ for battery boxes and other ‘ebonite’ applications. Patented latex concentration by centrifugation. Patented manufacture of foams from latex as apposed to dry rubber. General Tyre & Rubber Co. formed. Later to become Gencorp Inc.
305
W. L. Utermark P. Schidrowitz and H. A. Goldsborough General Tyre
USA
Timeline
C. H. Gray and T. Sloper
1912
Place
Event
I. Ostromislenski
1915
USSR
S. J. Peachy
1915
UK
D. C. Brownlee and K. R. Uhlinger F. H. Banbury
1916
USA
First organic vulcanisation systems without sulphur; nitrobenzene and peroxides used (At about this time the importance of zinc oxide in accelerated cures was appreciated.) The first practical patent for chlorinated rubber. Solutions as varnishes and corrosion-resistant paint. Patented production of thermal blacks from natural gas.
1916 1917 1917 1917 1918 1920 1920 1920
USA Japan Japan USA USA
1920 1920 1920 1920 1921
World
J. Gates B. F. Goodrich G. D. Kratz P. Schidrowitz
S. M. Cadwell I. J. Cooper P. Schidrowitz G. Bruni and C. W. Bedford
UK
USA UK Italy USA
Introduced the first rubber ‘internal mixer’. Yokohama Rubber Co. founded. Sumitomo Rubber Incorporated. Invented the ‘V’ belt. Invented ‘Vulcalock’ for bonding natural rubber to metal. Discovered the effect of diphenylguanidine (DPG). World production of natural rubber 350 000 tons. Pre-vulcanisation of latex and its use to manufacture dipped goods. Natural rubber production 350 000 tons, only 37 000 tons wild. Developed aldehyde-amine antidegradants. Formed Cooper Corp., later Cooper Tyre & Rubber Co. Discovered the pre-vulcanisation of latex. Mercaptobenzthiazole (MBT) discovered, independently.
Tears of the Tree
Date
306
Name
1922
UK
B. E. Lorentz S. M. Cadwell R. H. Marriott
1922 1922 1922
USA USA UK
Coloumbian Carbon Goodyear W. A. Gibbons
1922 1923 1923
USA USA USA
E. Hopkinson and G. Bruni W. F. Russell Revertex
1923
Italy
1923 1923
USA Malaysia
1924 1924
Germany USA
1925
Germany
1925
USA
M. Cadwell, H. Gray, and H. A. Winklemann
H. L. Fisher
Stephenson Reduction Plan introduced to cut output and force up the price of natural rubber. A disaster and soon withdrawn. Thiurams introduced. Xanthates introduced. Suggested making rubber thread by extruding latex through a jet into a coagulating bath. Coloumbian Carbon introduced a range of furnace blacks. Introduced cotton tyre cord. Patented modern process—extrusion of compounded latex through multiple glass jets into coagulating bath with continuous draw-off of threads for drying/curing. Zinc dithiocarbamates introduced. Patented organic fatty acid/zinc oxide use in vulcanisation. Revertex formed in Malaysia to produce latex concentrate by a heat process. Fossilised rubber 60 000 000 years old found. Cadwell and Gray/Winklemann independently develop the first commercially feasible antioxidants.
307
Serious work began on the synthesis of synthetic polybutadiene (Buna). The first commercial use of cyclised rubber as metal–rubber bond interface.
Timeline
Stephenson
Name
1925 1925/1926
Malaysia
Rosenbaum H. L. Fisher
1926 1927
UK USA
Henry Ford
1927
Brazil
J. C. Patrick
1928
USA
W. Semon
1930
USA
E. Tschunker
1930 1930
World Germany
1930s 1931
USA
Carothers, Williams, Collins, and Kirby
Event First commercial antioxidants (amines) introduced—staining. Rubber Research Institute of Malaysia formed under Dr G. Bryce. Took over research labs of the Rubber Growers, Association. Quote: ‘Synthetic rubber is dead’. Working for B. F. Goodrich, put cyclised rubber on a commercial footing. Materials ranged from gutta-percha-like to shellac-like thermoplastic resins. Used in ‘Vulcalock’ process to bond vulcanised rubber to most surfaces for chemical protection. He began to build ‘Fordlandia’—a complete town in the jungle with (eventually) a plantation of over a million rubber trees. Patented ‘Thiokol’—first commercial synthetic rubber. Note that this is not a sulphur cure, just metal oxides and possibly quinones. Suggested diffusion after vulcanisation of protective agents into rubbers to extend life. World production of natural rubber 850 000 tons. Buna N and Buna NN discovered (nitrile rubbers of 25% ACN and 35% ACN). Introduction of amine derivative antioxidants (but still staining). DuPont invented Duprene. Became polychloroprene (Neoprene).
Tears of the Tree
Place
308
Date
S. Ishibashi I. G. Farben C. Dufraisse and Drisch
1932
USSR
1933 1933 1933/1934 1934
World USA Germany Brazil
Firestone Goodyear
1935 1935 1935 1936
USA USSR USA USA
IG, etc.
1936
Germany
O. Bayer R. M. Thomas
1936 1936 1937 1937
France Netherlands Germany USA
N. Christensen E. Tschunker
Goodyear
Forms Bridgestone Co. Ltd. Discovered sulphenamides—adducts of MBT with amines. Observed that rubber extract can be added to rubber to improve its ageing. Russia manufactured SKA, followed by SKB (polybutadiene rubbers). Synthetic rubbers first featured in statistics at 2000 tons. Invented the ‘simple’ ‘O’ ring seal. Buna S patented and produced (styrene butadiene copolymer). Tropical leaf blight wiped out the plantation of ‘Fordlandia’. Fordlandia 2 begun but again wiped out. The end of Brazil’s dream of rubber plantations. Bought the Kelly–Springfield tyre company. Sovprene; equivalent to neoprene. Introduced the pneumatic tractor tyre. Introduced ‘Pliofilm’ (rubber hydrochloride) as a thin transparent packaging film, although patented a couple of years or so earlier. IG and Metallgesellschaft both used chlorinated rubber to bond steel and nitrile rubber or polychloroprene. Institut Francais du Caoutchouc set up in Paris. Rubber Stichting (foundation) established. Developed urethane rubbers. Butyl rubber.
309
Japan Germany France
Timeline
1931 1932 1931
Name
Continental Pintin
Event
1938
UK
1938 1938 1939 1939
USA France UK USA
British Rubber Producers Research Association created. Later Malaysian Rubber Producers Research Association (MRPRA) then Tun Abdul Razak Research Centre (TARRC). Introduced rayon tyre cord. Introduced the steel cord bias ply truck tyre. Claimed the word ‘latex’ was in use as early as 1662. First use of plasticised PVC as cable sheath.
1939 1940 1940 1941 1941 1943
USA USSR World USA Korea USA
1943 1943 1940–1945
Germany Germany Germany
1940–1945
Germany
Nitrile rubber produced in the States. SKI—polymerised isoprene (synthetic natural rubber). Natural rubber production 1 500 000 tons, synthetics 150 000 tons. Took out the first patent for injection-moulding rubber articles. Hankook Tyre Co. founded. GR-S production started (now known as SBR). Government rubber-styrene becomes styrene butadiene rubber (cf. Buna S). Patented tubeless tyres. First patent relating to urethane rubbers. Nitrile rubber lattices used for many dipped goods. Use of PVME to heat coagulate and thus make thick films with a single dip also found (by accident). Triisocyanate triphenyl methane developed as a rubber–metal bonding agent. Known today as Desmodur R.
Tears of the Tree
W. P. Cousino
Place
310
Goodyear Michelin T. R. Dawson Union Carbide and Goodrich
Date
Dow Corning and General Electric Michelin B. F. Goodrich Goodyear Michelin DuPont Goodrich
Silicone rubber. Not a sulphur cure; peroxides used.
1946 1947 1947 1948
France USA USA France
1948 1949 1950
USA USA World
1950s 1950s 1951 1953 1954 1954
Brazil Italy UK Taiwan USA
1954
USA
1955 1955 1956
Italy USA USA
Patented the steel-braced radial tyre. Tubeless tyres introduced in the US. Introduced nylon tyre cord. Michelin introduced the radial tyre (the cords run bead-to-bead at 90 to the wheel direction). DuPont develops fluoropolymers. Acetate rubbers developed. Natural rubber production 1 900 000 tons, synthetics 800 000 tons. Introduction of phenolic antioxidants (some non-staining). Last wild rubber exported. Pirelli launches its steel-belted radial, the ‘Cinturato’. First British tubeless tyre. Founded Tayfeng Rubber Industries—later Tayfeng Tyre Co. Announced high-cis synthetic ‘natural rubber’ based on Ziegler/Natta catalysts. Introduction of substituted para-phenylenediamine antiozonants (still staining). Introduced the first radial farm tractor drive tyre. Low-cis synthetic ‘natural rubber’. Michelin imports first radials into USA.
311
Pirelli Firestone Michelin
USA
Timeline
Pirelli Dunlop Ma Chi San Goodrich
1945
Place
Event
R. and J. Newton
1957
USA
DuPont
1958 1959 1960
USA World World
Park Incheon
1960
Korea
Goodyear
1962 1964
USA UK
B. F. Gooodrich Toyo Tyre and Rubber Co.
1965 1968
USA USA
Formed Hoosier initially to make racing tyres by retreading road tyres (see 1979). Introduced fluoroelastomers. Natural rubber production overtaken by the synthetics. Natural rubber production 2 000 000 tons, synthetics 2 500 000 tons. Samyang Tyre Co. Ltd founded in Yang-Dong. Later to become Kumho Tyres. Introduced polyester tyre cord. Albany Court built in London above St James, Underground station. The first building to rest solely on natural rubber anti-vibration mounts. Manufactured the first US radials. First Japanese company to establish overseas sales company.
MRPRA
1969 1970 1970
USA UK World
Dunlop Dunlop
1972 1972
UK UK
Yokohama Rubber Co. begins manufacture in the US. Urethane crosslinking of natural rubber discovered. Natural rubber production 3 000 000 tons, synthetics 5 750 000 tons. Dunlop introduced the run-flat tyre (Denovo). Dunlop introduced the tubeless tyre.
Tears of the Tree
Date
312
Name
World
1978 1979
France UK
1979 1980
USA
1984
USA
Sumitomo
1984 1987
UK Malaysia
Tayfeng Tyre Co.
1978 1990
Taiwan World
1990
World
Michelin D. S. Campbell, D. J. Elliott, and M. A. Wheelans R. and J. Newton
Thermoplastic rubbers which have the properties of a vulcanisate at ‘room temperature’, but can be moulded and remoulded at high temperatures, start to become important. Radial tyres entered Grand Prix racing. Introduced thermoplastic natural rubber.
313
Formed R. & J. Mfg Corp. specifically to make racing tyres. World natural rubber production 3 850 000 tons, synthetics 8 250 000 tons. The Law and Justice Centre in San Bernadino County was the first building to be supported on high-damping (earthquake-resisting) natural rubber bearings. Bought Dunlop’s European tyre business to create SP Tyres. Epoxidised natural rubber became commercially available (for a short while)—chemically modified to move into areas unique to the synthetics (oil resistant and high damping). Changed name to Federal Corporation. Natural rubber production 5 200 000 tons, synthetics 9 300 000 tons. Perhaps five billion plantation Hevea braziliensis trees producing rubber worldwide.
Timeline
1972
Date
Michelin
1992
Samyang Tyre Co. Ltd
1996 1997
Goodyear
1999
Place
Event
Korea
Launched its ‘green’ radial tyre with silica as a rubber reinforcing agent, the ‘Green X’. Company name changed to KUMHO Tyre Co., Ltd.
314
Name
World natural rubber production 6 500 000 tons, synthetics 8 700 000 tons. Goodyear joined forces with SP Tyres/Sumitomo to create one of the largest global tyre companies.
Tears of the Tree
Bibliography Journals India Rubber Journal, first published in the UK in 1884, later to become the Rubber Journal and now the European Rubber Journal. India Rubber World, first published in the US in 1889. Rubber Age.
Books Akers, C. E. (1914). The rubber industry of Brazil and the Orient. Methuen & Co, London. Ascherson, N. (1999). The King Incorporated (Leopold II and the Congo). Granta Books, London. Barron, H. (1942). Modern synthetic rubbers. Chapman & Hall Ltd., London. —— (1947). Modern rubber chemistry. Hutchinson’s, London. Bateman, L. (ed.) (1963). The chemistry and physics of rubber-like substances. Maclaren & Sons Ltd., London. Baum, V. (1947). The weeping wood. Michael Joseph, London. Brown, H. (1914). Rubber, its sources, cultivation and preparation. John Murray, London. Browne, E. (1912). Rubber. Adam & Charles Black, London. Buder, A. and Langer, M. (1998). Latex in art of the 20th C—problems and conservation. Diploma thesis in German. Buist, J. M. (1955). The ageing and weathering of rubber. W. Heffer & Sons Ltd., Cambridge. Coates, A. (1987). The commerce in rubber: the first 250 years. Oxford University Press, Singapore. Collier, R. (1968). The river that God forgot. Collins, London. Conrad, J. (1902). Heart of Darkness. Penguin (1999), London. Cook, J. G. (1963). Rubber. Frederick Muller Ltd., London.
316
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Cook, P. G. (1956). Latex, natural and synthetic. Chapman & Hall Ltd., New York. Davis, C. J. and Blake, J. T. (eds) (1937). The chemistry & technology of rubber. Reinhold Pub. Corp., New York. De Chasseloup Laubat, F. (1942). Franc¸ois Fresneau, pe`re du caoutchouc. Les Petits-Fils De Plon Et Nourrit, Paris. (In French.) Dean, W. (1987). Brazil and the struggle for rubber. Cambridge Univ. Press, London. Del Veccio, R. J. (ed.) (2003). Fundamentals of rubber technology. Rubber Div. A.C.S., Akron. Drabble, J. H. (1973). Rubber in Malaya 1876–1922. Oxford University Press, Kuala Lumpur. Ghosh, H. H. (1928). The realm of rubber. Draymond, Calcutta. Giersch, U. and Kubisch, U. (1995). Gummi—die Elastische Faszination. Nicolai, Berlin. (In German.) Goodyear, C. (1937). Gum elastic. Maclaren & Sons Ltd., London. (IRJ reprint.) Gratton, D. W. (ed.) (1993). Saving the 20th C: the conservation of modern materials. Canadian Conservation Institute, Ottawa. (Full Conference Proceedings.) Hancock, T. (1853). Specification of fourteen patents for the treatment of India rubber. Printed privately, London. —— (1856). Origin and progress of the caoutchouc or India-rubber manufacture in England. Longman, Brown, Green, Longmans and Roberts, London. Hardenburg, W. E. (1912). The putumayo—the Devil’s paradise. T. Fisher Unwin, London. Hauser, E. A. (1930). Latex; its occurrence, collection, properties and technical applications. (trans. W. J. Kelly). Chemical Catalog Co., New York. Hochschild, A. (1998). King Leopold’s ghost—a story of greed, terror and heroism in Central Africa. Macmillan, London. Langer, M. (1999). The latex sculptures of Eva Hesse (Diploma Thesis in German). Loadman, M. J. R. (1998). Analysis of rubber and rubber-like polymers (4th edn). Kluwer Academic Pub., Dordrecht. Mason, P. (1979). Cauchu: the weeping wood: a history of rubber. Australian Broadcasting Commission, Sydney.
Bibliography
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Mathyoo, A. T. (1960). The rubber manufacturing industry. Assoc. of Rubber Manufacturers in India, Calcutta. Morel, E. D. (1906). Red rubber. T. Fisher Unwin, London. Naughton, W. S. (1937). Synthetic rubber. Macmillan & Co. Ltd., London. Pearson, H. C. (1911). The rubber country of the Amazon. India Rubber World, New York. Porrit, B. D. (1931). The early history of the rubber industry. R.G.A., London. Potts, H. E. (1920). The chemistry of the rubber industry. Constable & Co. Ltd., London. Roberts, A. D. (ed.) (1988). Natural rubber science and technology. Oxford University Press, Oxford. Rosenbaum, J. L. (trans.) (1927). Gottlobs technology of rubber 1915, 1925. Maclaren & Sons Ltd., Edinburgh. Royal Botanic Gardens, Kew (1906). Selected papers from the Kew bulletin; III–Rubber. H.M.S.O., London. Rubber Growers’ Association (1928). Latex. R.G.A., London. Schidrowitz, P. (1911). Rubber. Methuen & Co. Ltd., London. —— and Dawson, T. R. (1952). History of the rubber industry. W. Heffer & Sons, Cambridge. Schotz, S. P. (1927). Synthetic rubber. Ernest Benn Ltd., London. Scott, J. R. (1958). Ebonite. Maclaren & Sons, London. Seeligmann, T., Lamy Torrilhon, G., and Falconnet, H. (1903). Indiarubber and gutta percha. (trans. J. D. Mcintosh). Scott Greenwood & Co., London. Slack, C. (2002). Noble obsession. Hyperion, New York. Spence, D. (ed.) (1909). Lectures on India-rubber. International Rubber & Allied Trades Exhibition, Ltd., London. Stanfield, M.E. (1998). Red rubber bleeding trees. NW Amazonia 1850–1933. Univ. New Mexico Press, Albuquerque. Stern, H. J. (1955). Practical latex work. Blackfriars Press, Leicester. Stevens, H. P. and Beadle, C. (1915). Rubber production and utilisation of the raw product (2nd edn). Sir Isaac Pitman & Sons Ltd., London. Storrs, Sir R. (1946). Dunlop in war and peace. Hutchinson & Co. Ltd., London. Tedlock, D. (trans.) (1996). Popul Vuh (the Mayan book of Council). Simon & Schuster, New York.
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Terry, H. L. (1907). India-rubber and its manufacture. Archibald Constable & Co. Ltd., London. Weber, L. E. (1926). The chemistry of rubber manufacture. Charles Griffin & Co. Ltd., London. Wicherley, W. (1911). The whole art of rubber growing. The West Strand Pub. Co., London. Wickham, H. A. (1908). On the plantation, cultivation and curing of para´ Indian rubber. Kegan Paul, Trench, Tru¨bner & Co. Ltd., London. Wolf, H. and Wolf, R. (1936). Rubber, a story of glory and greed. Covici. Friede, New York. Woodruff, W. (1958). Rise of the British rubber industry during the 19th C. Liverpool University Press, Liverpool.
Index A crime against humanity 130 ABIR 133 see also Anglo-Belgian India-Rubber Co. ABR 184, 185, 186 see also butakon Abrasion resistance 213, 229 Abrasive rubber 223 Abrasive wear 270, 273 Acade´mie Royale des Sciences 15 Academy of Science, Paris 19, 20, 24 Accelerators 208–215, 253, 254, 261 Accelerene, see nitrosodimethylaniline Acetylene black 225–7 ACN 185 see also nitrile rubber Adams, Roger 178, 180 African rubber industry—common thread with South American 145 Ageing processes (illustration and types) 245, 247–250 Agglomerates 227 see also carbon black—variations in properties Aggregates 227 see also carbon black—variations in properties AIA 113, 114, 119–123 AIC 121–123 Alarco, Abel 150 Alberta 137 Alice Pike 117, 119 Almeida, Dr 47 Amazon xviii, 10, 16, 17, 25, 26, 81, 82, 84, 86, 93, 103, 145, 146, 148, 150, 153, 158, 160, 162 Amazonas, see SS Amazonas Amazons 17 American shoe trade 74
Ameripol 175 Amine antioxidants 174 Ammonia in vulcanisation 209 Amputated body parts 128, 130–131, 135, 153 Anderson, William 96 Anglo-Belgian India-Rubber Co. 125 Aniline in vulcanisation 209 Antidegradants 242, 249 Antioxidants 174, 239–243 mode of operation 242 Antiozonants 240–241, 254, 257 mode of operation 242 Anti-slavery and Aborigines Protection Soc. 156, 157 Antonio de Herrera Tordesillas 12 Anversoise 125, 133 Apocynaceae 24 Arana, Julio Ce´sar 148–163 after 1920 162 American politics in the Putumayo 157 death 162 defence to UK Committee 161 early life 148 first rubber estate 149 hat salesman 148 in the Putumayo 150 operating structure 150–151 reason for UK company 150 rubber bug 69, 149 S. American murmurings against 157 self-justification 158 Arana, Lizardo 150 Arau´jo, J. G. 146 Arburg 203 Artificial reefs from used tyres 266 Asphalte 223
320 Association Internationale Africaine, see AIA Association Internationale du Congo 121 Athletic tracks from recycled rubber crumb 271 Atmospheric ageing 247 effect of trace metals 249 mechanism 249 Atmospheric pollution 243 AU 187 see also polyester urethanes Aublet, J. C. F. 24, 25 Auleytner 1 Austin/Morris 74 Automotive tyres 173, 174, 175 Auxochromes 244 Avon Rubber Co. 73 Aztecs 4, 10, 11, 13, 25 Bacteriological devulcanisation 273 Baer 170 Balata 28 Ball courts 2, 3, 6, 7, 9 and graveyards 9 positions 4 rings 5 shape 2 teams 4 victors 6 Yagul 2, 3 Ball game 2, 5, 6, 8, 9, 10, 12, 27 decapitation 7 extent 2 religious significance 6, 7 Balls (soft rubber) 204 Banbury 198 principle of operation 198 Banbury, Fernley 198 Barclay, James 72 Barre`re, Pierre 24 Barrier technique for protecting vulcanisates 250 Barytes 224 Batch process 200 Batey, see ball game
Index Baum, Vicki 15, 26 Bayer 21, 168, 174 Beer’s law 248 Bele´m (Para´) 81, 84, 86 Belgian Parliament 136–138 Belichick, Meg 258 Belterra 103 Beni River 146 Bennett, James Gordon 116–118 Berlin Botanical Gardens 25 Berlin Conference 123 Bertin, M. 19, 20 Betsy & Eliza 143 Bewley, H. 47, 201 BIIR 185 see also brominated IIR Bill of entry, see SS Amazonas Biosynthesis 187 Birley, Henry 43, 66 Birley, Herbert 66 Birley, Hugh Hornby 56 Birley, Richard 66 Birley, Thomas H. 66 Blend morphology 229–231 Blending 216, 231, 232 Blends and tyre composition 229 Blood Moon 8 Blooms different types, causes and mechanisms 250–257 inorganic fillers 249 Blown sponge 66 Bolivian rubber 153 Bonded materials 53, 270 Botanic Gardens of Buitenzorg 95 Botanic Gardens at Kew 77, 83, 84, 85, 88, 92–99, 103 Bouchardat, A. 168 Boyle, Robert 164 BR 166, 169, 184, 274, 275 see also Butadiene rubber, buna and polybutadiene Bradford-on Avon 43, 68, 70 Brandis, Dietrich 84 Brazil 25, 28, 77, 81, 86, 89, 92, 101, 148, 149, 158, 162
Index Brazil nuts 90 Bridge, David 190 Brighteners 223, 228, 243 British Parliament 147, 163 Brockedon, William 56, 62, 63, 66, 68, 207 gives us the name ‘vulcanisation’ 65 Brownian motion 165 Brownlee 225 BTR Industries 48 Buffalo Bill 171 Buna 174 see also butadiene rubber Buna S. 174 see also styrene butadiene rubber Busse 165 Butadiene 175, 176, 181, 184, 185 Butadiene acrylonitrile rubber 174 see also also nitrile rubber Butadiene rubber 166, 169, 229, 274 energy requirements 274 Butakon 184 Butyl latex 250 Butyl rubber 176, 181, 231, 250 Cahuchu 15 Calcium carbonate 257 Calcutta Botanical Gardens 84 Calender 190–195 shearing 192, 195 three roll 192 Cameron, Lovatt 112, 117, 119 Candy 97 Canisius, Edward 133 Cantly, N. 99 Caoutchouc 15, 22, 23, 48, 53, 59, 60, 72, 222 origin and meaning 15, 26 origin and meaning (Kechuan Indians) 26 origin and meaning (Cobo, B.) 27 origin and meaning (Holguin, D. G.) 27 origin and meaning (Maı¨nas Indians) 26 origin and meaning (Tupi Indians) 26
321
Caoutchouc ivory 234 see also ebonite Caoutchouc springs 48 Caoutchouc whalebone 234 see also ebonite Cap Ferat 137 Caqueta´ river 162 Carbon black xxv, 220, 261, 273 and Chinese 224 and Egyptians 224 general history 224 indicative micrograph 227 loadings 228 types and sources 225 variations in properties 225–227 Carbon dioxide 187, 204, 275, 276 Cariflex 185 see also IR Carioca, Manoel 146 Carothers, Wallace 177–180 death 180 first commercially successful synthetic elastomer 179 first successful synthetic fibres 179 marriage to Helen Sweetman 180 phial of cyanide 178 Carter, W. H. J. 86 Casement, Sir Roger 134–136, 141, 156–163 report of Arana 157 report to UK Committee 159 Castilloa elastica 16, 23, 24, 27, 97 origin of the name 25 Castilloa seedlings 93, 97 Catheters 50 Catholic church 126 Cauchuc 26 see also caouthouc Ceara´ 149 Ceara´ seedlings 93, 97 Cement industry and scrap tyres 272 Cervantes, Vincente 25 Ceylon (Sri Lanka) xxviii, 83, 84, 93, 95, 96, 99 Chaffee, Edwin 190, 194, 220, 222 Chalk 223, 228 Chalking 249
322
Index
Channel black 224, 226 see also Carbon black—general history Chapman, William 93 Charles Macintosh & Co. 43, 56, 60–62, 66, 67, 68, 74 Cha´vez, Ricardo 84 Chemical devulcanisation 260 Chichen Itza 3, 6, 9 Chicle 187 Chinese and carbon black 224 Chloroprene—synthesis of 178 Chlorinated IIR 184 Chloroprene 167, 184 see also polychloroprene Chlorosulphonated polyethylene 183 Choate, Rufus 40, 41 Chrome salts 222 Chromium, see Trace metals—effects on vulcanisates Chromophores 244 CIIR 184 see chlorinated IIR Cinchona tree 18, 83, 85 Cis-polyisoprene 187, 254 see also natural rubber and synthetic natural rubber Clay 13, 223, 257 CO 183 Coal tar naphtha 53 Cobalt, see trace metals—effects on vulcanisates Cobo, B. 27 describes latex stockings 13 Co-continuous phase 229 Coffee 92, 97, 101, 103 Cold cure process 214 Collins, James 84, 92 gets first hevea seeds in UK 84 Collins, Arnold 178 Colorants 222, 223, 224, 228, 257 Columbus, Christopher 12 Comite´ d’Etudes du haut-Congo 120–124 Compagine du Kasai 131 Compatibiliser 218, 219
Competing reaction 242, 248 Compte de Chassloup Loubat xxvii, 14, 21 Condoms xxv, xxviii, 277 Congo xxviii, 108–142, 145, 153, 155, 156, 157, 162 Congo Free State 121, 123, 130, 136, 138 Congo Reform Association 135, 138 Conquistadors 2 Conrad, Joseph 128, 134 Copper, see Trace metals—effects on vulcanisates Corn People 2 Cortez, Hernando 6, 11, 12 Council Book 6, 7 see also Popol Vuh Spanish translation 8 Count Savorgnan de Brazza 121 CR 167, 177, 184 see also polychloroprene Craig, see Semon, Sloan & Craig Cramer, P. J. S. 95 Crazing 249 Cross, Robert 83–85, 93–97, 107 Crosslink density 211–213, 217, 218, 223 Crosslink distribution in blends 216–217 CSM 183 see also chlorosulphonated polyethylene Cure 65, 66, 189, 204, 207, 235, 253, 271 see also vulcanisation Curing 207 see also vulcanising Curing and vulcanisation xxvii, 207, 213, 214 Curing related to smoking 214 Custer, General G. A. 170 Cutler, Horace 36, 37 Daily Tribune 41 Dandelion 22 Dawson 1 Day, Horace 36–43, 76 Decapitation 6, 128, 155
Index Deformation 164, 165 DeForest, William 29, 38 Degradation xxvi, 190, 224, 239, 240, 243, 247–250, 255, 256, 263, 269, 272, 277 by abrasion 246 by chemical attack 246 by continuing vulcanization chemistry 247 by oxidation 239–241, 255 sunlight induced 239, 246 Del Castillo, Juan Deigo 25 Devulcanisation 260, 261, 273 Dickens Charles 23 Differential solubility of chemicals in rubber blends 216–217 Diffusion theory in limiting degradation 243 Dilkes, Sir Charles. M. P. 134 Diphenylguanidine 208 Dipped latex products 204, 205 Discolouration 243, 244, 251, 256, 257 Discrete phase—see blend morphology Dock fenders from used tyres 266 Domaine de la Couronne 137, 139 Domaine Prive´e 124 Double textured fabric 53, 58, 59 Dough waterproofing 51, 60 DPG, see diphenylguanidine DPNR 185 see also NR Drisch, see Dufraisse, C. Drummand Hay, James 86 Dufraisse, C. 240 Dumping 258, 260 Dunlop 204, 224, 225 Dunlop Standard Aerospace Group 48 Dunlop, John Boyd 66, 73, 144 DuPont 177–181 Dyera Costulata 28 Eagle Rubber Co. 31 Ebonite 38, 66, 232, 247 Goodyear 40, 42
323
Hancock’s documented products 234–235 illustrated products 236–237 Nathaniel Hayward 38 origins and history 232 products 233 synthetic 235 use for making moulds 233 Ebonite rooms 40 Ebonite skin 233 Efficient vulcanisate (EV) 212, 213 Egyptians and carbon black 224 El Encanto 154 El Tajin 3, 6 Elastic xxix, 22, 33, 35, 49, 164, 167, 168, 216, 225, 232, 260 Elastic bands 164, 165, 260 Elastic properties 164, 169, 170, 207, 228 Elastomeric 164, 186, 229, 263 Elder-Dempster Shipping Line 131, 132, 135 Eli, William 34–36 Elizabeth Lyne 48 Ellis, Wynne 58 Emulsion phase polymerisation 181 Enema syringes 16 Enema tree 24 Energy requirements for recycling 264 Engineering industry—lack of 190 ENR 185 see also NR EOT 185 EPM 181, 182, 231 see also Nordel EPDM 181, 182 see also ethylene propylene rubber Etat Inde´pendant du Congo 123 Ethylene 181, 182 Ethylene norbornene 181 Ethylene propylene rubber 181, 216, 231 EU 186, 263, 266, 272 see also polyether urethanes Everington and Ellis, see Ellis, Wynne
324
Index
Experiments with elastic bands 165 Extending oils 220, 228 Extrudate 201 Fanshawe’s Improved Rubber Cloth 58 Fatigue cracking 213 Fatty acids 208, 209 Federal Highway Administration 272 Feeney, Mary 156 Ferris, Charles 84 Ficus elastica 27, 28, 83, 97 Fillers—general purpose xxix, 220, 221 Firestone 224 First World War 162, 225, 238 see also Great War Flash 201 Flex cracking 270 Fluorel 183 see also Viton Fluorocarbons 262 Fondation de la Couronne 137, 138 Fondation of Niederfulbach 140 Force Publique, see Leopold—private army Ford, Henry 102, 103 Fordlandia 102, 103 Formers 13, 189, 204 Foxton, R. N. 253 FPM 183 see also Viton Francisco de Melo Palheta 92 Francisco Inoceˆncio de Souza Coutinho 92 Frank and Marckwald 225 Free sulphur 253, 257, 260 French Guiana 17, 23, 24 Fresneau, Francois 13, 17–21, 24, 25, 50, 168 ‘memoire’ 19 and Bertin, He´rrisant and Macquer 20, 21 early life 17 in the new world 18 La Gataudie´re 17, 18, 19, 21 M. Duplessis 17
marriage 18 second marriage 19 syringes 16, 19, 24 the Marquese d’Ambres 17 waterproof fabrics 20 widowed 19 with Charles Marie de la Condamine 17–18 Frosting 251 Fuel 243, 272, 273, 274, 276 Fuel economy 229 Funtumia elastica 28 Furnace blacks 225–227 Galloway, P. D. 253 Galoshes 10, 261 Gandee & Steele 38 Gas phase polymerisation 175, 181 General Gordon and Khartoum 121–122 General purpose elastomers 187 General purpose rubbers 167, 187 Genus Globosa 28 Geon Corp. 176 Getting rich in the Congo 109 Gielgud, Henry 159–160 Golden rod 22 Golf balls 28 Gonzalo Fernandez de Oviedo 12 Goodrich, B. F. 173–176, 224 Goodyear, Amasa 29 Goodyear, Charles xxvii, 29–45, 62–69, 71–77, 168, 188, 207, 208, 209, 212, 222, 224, 228, 233, 253, 260 books 41 death 44 death of Clarissa 42 different stories about discovery of vulcanisation 33–36 and Horace Day 39 and Horace Day in court 40–41
Index and Nathaniel Hayward 31–32 discovers vulcanisation 32–33 early life 29–30 French decorations 43 jail 29, 30, 37, 43 marriage to Clarissa 29 marriage to Fanny Wardell 42 visits Marlborough Cottage(?) 66 Goodyear, Harriet 29 Goodyear’s Vulcanite Court 40 Goswell Road 55, 57, 60 Gough-Joule effect Government Rubber (GR) 170, 174, 175, 176 GPO 183 see Parel GR-A (government rubber—acrylonitrile) 175 see also nitrile rubber Grasshopper 57 Great exhibition 40, 42, 46, 70, 81, 233 Great War 140, 141, 169 see also First World War Green, Charles 58 Greenhouse gas 187 GR-P, see thiokols GR-S (government rubber—styrene) 174, 176 see also styrene butadiene rubber Guatemala 6, 7 Guayule 28, 187 Gubbins, John 157, 160 Guiana 17, 18, 19, 23, 24, 28 Guibal, see Rattier Gum Elastic 41, 233 Gummi optima 12 Gunn, Marjorie 172 Gutta percha 28, 45, 46, 47, 201, 231 HALS, see Hindered amine light stabilizers Hancock, Charles 46, 47
325
Hancock, Fanny 46 Hancock, Harriet 46 Hancock, James 45, 48 Hancock, James Lyne 48, 60–62, 75 Hancock, John 45, 46, 56, 59 Hancock, Maria 46 Hancock, Thomas xxvii, 37, 38, 40, 43, 45–80, 82, 84, 168, 188, 189, 220, 222, 224, 231, 233, 253 against Stephen Moulton 72–73 death 79 early experiments 48 in court against American shoe importers 74 Kensal Green cemetery 79 letters to Hayward & Day 76 Letter to Sir W. J. Hooker 77 ‘magnum opus’ 74 medallion 71, 78 ‘Narrative’ 52, 62, 66, 70, 76, 77 retirement 65 rubber products 71 rubber tube controversy 60 sees Goodyear’s vulcanised rubber 62 vulcanisation 62 vulcanisation patent 63–64 vulcanising patent 222 Hancock, Walter 46, 55 Hancock, William 46 Harburger-Gummi-Kamm-Co. 235 Hard rubber 38, 66, 232 see also ebonite Hardenburg, Walter Ernest 153–162 documentary evidence against Arana 155 evidence to UK Committee 161 ‘framed’ by Arana 161 in Iquitos 154 marriage 157 on the Putumayo 153–154 publishes ‘The Putumayo’ 161 stories of atrocities 153–5 to London 156
326
Index
Harris, John H., Revd 156 Hayward Rubber Co. 38, 68 Hayward, Nathaniel 31, 32, 34, 38, 68, 69, 74, 76, 233 tombstone 38, 39 Haze 256 Healy, George 42 Heart of Darkness 128, 134 Heat ageing, mechanism of 248 Heinzerling, C. 223 Heneratgoda Gardens 93, 97 Henriques, R. 239 Herclor 183 see also epichlorohydrin Hernandez, Fernando 23 Herodotus 1 Hevea 26, 81, 88, 93, 96, 97, 99, 107, 275, 276 Hevea biomas 275 Hevea braziliensis 22, 24, 25, 27, 28 location in Amazonia 25 origin of the name 25 Hevea guianensis 24 Hevea peruviana 24 Hevea plantations 275, 276 Hevea seedlings 81, 93, 97 to India 93 to Sri Lanka 93, 95 to Singapore 94, 95 Hevea seeds and ideas for cultivation 84 Hevea trees 88 Hill, Julian 179 Hindered amine light stabilizers 248 Hoffer, R. 223 Holguin, D. G. 15, 27 Holy Grail 239 homo-polymers 181 Hooker, Sir Joseph 84, 87, 88, 103 Hooker, Sir William J. 77, 85 Huallaga river 149 Huitito native 11, 153 Hunahpu 8 Hypalon 183 see also—chlorosulphonated polyethylene
Ic¸ana river 146 IG Farbenindustrie 170, 174, 176, 181 IIR 176, 181, 184, 185 see also butyl rubber IM 176, 182 see also polyisobutylene Impact modified plastics 231 Incas 10, 15, 26 Incompatibility 216 India Office 83, 87, 92, 93 India Rubber, Gutta Percha and Telegraph Works Co. 47, 225, 235 India rubber 22, 23, 33, 51, 58, 60, 76 Industrial revolution 188, 189 Injection moulding 201–204 Inorganic fillers and blooming 256 Intermix 197 Internal combustion engine xxviii, 144 Internal mixers 197 Internal stresses and blooms 255–256 International Commission of Enquiry into the Congo 136 Iquitos 148, 149, 150, 151, 154, 155 IR—synthetic natural rubber 185 Iron Duke 192, 194 ISO 1629 182 Isobutylene 181, 184 Isoprene 168, 176, 181, 184, 186 Izapa 6 JC Arana & Hermanos 150 Joao Martins da Silva Coutinho 92 Jonson, Ben 12 Johnson, W. H. 26 Jones, Fordyce 16, 106 Jones, Sir Alfred 132 Juliaans, Arnoud 25
Index Kaiser Wilhelm II 168 Katz 165 Kautschuk 15 Keir, James 21 Kew Bulletin III 95, 96 Kik 26 Kindersleys, the 101 King Leopold II, see Leopold II King, Guy 154 Kingston House 70 Kingston Mill 70 Kondakoff, I. 168 Koroseal 174 see also PVC Korzeniowski, Jo´seph Konrad 134 see also Conrad, Joseph Krynac 185 see also nitrile rubber Kuala Kangsar 101 first plantings of Hevea 99 one remaining tree (photo) 99 Kuba people of the Congo 130–1 La Condamine, Charles Marie de xxvi, xxvii, 13–19, 24, 26, 164, 168 his early life 13–16 with Francois Fresneau 17–18 with Godin and Bouguer 15 La Gataudie´re xxvii, 17–21 La Neuville, Father AJ de 23, 24 La Rochelle 21 Lamp black 224, 225 see also Carbon black—general history Landfill 260, 262, 263 Landolphia 24, 27, 28, 127 Lane, Edward 106 Latex xxv, 11, 13, 15, 16, 19, 22, 57, 58, 97, 101, 127, 188, 204, 271 collection in the Congo 27, 129 foam 204 pre-vulcanisation 204, 214–215 post-vulcanisation 215 sterilising 11 stockings described by Cobo 13 toys 206 Latex products—dipped xxvi, 204
327
Lead 257, 258 Leopold II 108–142, 145, 150, 156, 162 and Africa 111 Brussels Conference 112 buildings in Belgium 137–138 Catholic church camps 126 caught out in the Belgian Parliament 136 death 138 early years 110 focuses on the Congo 112 fooling the Belgians 123–124 fooling the US and Europe 121–122 King Edward VII 138 latex collection protocol 127 meets Stanley 120 policy raised in UK parliament 134 plans to ‘take over’ the Congo 112 private army 126, 127 sets out Stanley’s role 120–121 walls of defence 137 Leuchs, E. F. 232 Liberty tyres 175 Life rafts 180 Light catalysed degradation— mechanism 248 Light scattering 256 Light stiffening 249 Lime 222 Linseed oil 223 Lister-Kaye, Sir John, Bart 151, 160 Little ash girl 258, 259 Liverpool 87, 88, 89, 90, 131, 132, 150 Livingstone, Dr David 111, 114, 117 Loayza, Miguel 154 Low, Seth 143 Low, Sir Hugh 99 Ludersdorff, F. 233 Lunar Society of Birmingham 21 Lunatics 21 M group rubbers 182
328
Index
MA Hannah Co. 176 Macintosh, Charles 53–63, 71, 77, 189, 190 death 63 Macintosh, George 66 Macquer—‘Dictionnaire de Chymie’ 21 Macushi Indians 28 Madiera river 153 Magnesia 30, 31, 222 Magnesium oxide 223, 228 Magnesium silicate 222 Malaysia xxvii, 28, 94, 95, 96, 97, 98, 102, 105, 276 Malaysian plantation industry early problems 99 first plantings 99 latex profitability established 101 Malacca 101 Perak 99, 101 Ridley suggests large scale planting 99 Selangor 99, 101 Malaysian Rubber Producers Research Association 210 see also TARRC Mamore´ river 153 Manaus 81, 86, 88, 89, 90, 146, 147, 148, 150, 151, 153, 160 Manganese, see Trace metals—effects on vulcanisates Manihot glaziovil 28 Maran˜on river 148, 149 Marennes xxvii, 19, 21 Markham, Sir Clements 18, 82–85, 87, 92, 93 Marks 261 Marlborough 45 Marlborough Cottage 46, 47, 62, 66 Mastication 56, 57, 190 Masticator 37, 51, 52, 59, 60, 64, 191, 220 Matadi 123, 124, 125 Mattson, Morriss 34 Mayan civilization 1–9, 26
Mayan doll xxvi MBT, see mercaptobenzthiazole McNutt 224 Medical gloves xxvii, 205 Medical tubing 213 Mercaptobenzthiazole 208 and blooms 208 Mesoamerica 25 Mesoamerican civilizations xxv–xxviii, 1–11 Mesoamericans 220 Methyl rubber 168, 169, 235 Mexica, see Aztecs Meyer, Adolph 235 Meyer, von Susich & Valco 165 MFQ 184 MGF sports car 74 Micelle 256 Michelin 224 Microscopical techniques in blend analysis 217 Microwave devulcanisation 273 Migration—preferential of additives in blends 229 Mill intermixer 201 Mill sizes 195–197 Miller 171 Mini 74 Mitchell, Chapman 260 Mixers 190 Mixing mills 195, 196, 220 Moakes, R. C. W. 256 Modified blooms, see blooms—different types, causes and mechanisms Mokaya 2, 6 Moke, S. C. 225 Monomers 169, 174, 178, 181, 190, 210, 211 Montezuma 10–12 Montgomerie, Dr 47 Morel, E. D. 131–135, 138, 139 early awarness of Congo atrocities 132 West African Mail 133
Index Morphology of blends 229 Moseley, J. 224 Motor cars xxviii, 75, 223 first 144 first designed for pneumatic tyres 145 Moulding 197–201 compression 201 injection 201 transfer 201 Moulton bicycle 73 Moulton, Dr Alex 73 Moulton, Stephen 37, 43, 60, 62, 65, 68 equipment problems 193–194 in the US 69 life 68–73 marriage 69 MPQ 183 MPVQ 184 MQ 183 see also polydimethoxysiloxane Murphy, E. A. 204, 242 Murray, Captain George S. 87–89 Murton, H. J. 93, 96, 99 Nah, S. H. 251 Nairne’s of London 22 National Bureau of Standards 171 Natsyn 185 see also IR Natta, Guilio 181 Natural proteins 208 Natural rubber xxv–xxx, 2, 4, 8, 12, 19, 21, 22, 28, 46, 56, 95, 108, 164, 165, 166, 168, 173, 174, 175, 178, 181, 185, 187, 188, 190, 207, 208, 210, 214, 216, 217, 218, 219, 229, 231, 232, 240, 247, 254, 271, 274, 275, 276, 277 blood of sacrifice 9 chemically modified 232 energy requirements 274 Popol Vuh significance 8 production in the 20th C 144 Naugatuck Rubber Co. 38
329
NBR 167, 175, 185 see also nitrile rubber Negro river 85, 146 Neoprene 178, 184 see also polychloroprene Nickel, see Trace metals—effects on vulcanisates Nieuwland, Father Julius 178, 179 Nitrile rubbers 167, 217, 218, 262 Nitrosodimethylaniline 208 Non-staining antioxidants 242 Non-tyre rubbers in cars—problems with recyling 262, 263 Nordel 182 North British Rubber Co. 77 North, Colonel 125 NOX’s 243–244 NR 185 see also natural rubber Nuclear Magnetic resonance spectroscopy 217 Nunn, John Hancock 48, 62 Nylon 66 179 Nylon and World War 2 180 Nylon stockings 179–180 O group rubbers 183 Obedos 90 OENR 185 see also NR Oil 13, 183, 184, 185, 187, 216, 220, 224, 228, 232, 262, 263, 273, 274 Oli lacquer 250 Olli 26, 27 Olmecs 2, 9 One Hunahpu 8 Orella, Francisco de 17 Ostromislenski, I. 209 Ostwald, W. 210 OT 185 Otero, Germino Garrido y 146 Overshoes 31, 36, 143, 188 see also galoshes Oxidative degradation, see rubber—understanding of degradation
330
Index
PA 185 see also NR PAC 156–158 see also Peruvian Amazon Co. response to UK Committee 159–160 wound up 157 Pahl, W., see Heinzerling Para´ 81, 84, 86, 87, 89, 90, 92, 143, 144, 148, 150, 161, 166, 188 Para´ nuts 90 Para´ rubber 81 see also Hevea braziliensis Parachute canopies 180 Paraphenylene antiozonants and blooms 254 Paraphenylenediamines 241, 242 Paredos, Judge Ro´mulo 158 Parel 183 Paris Exhibition 41, 42, 233 Parkes cold cure process 65, 189, 214 Parkes, Alexander 65, 66, 77, 189, 214, 260 Parthenium argentatum 187 Particle size 225–226 see also Carbon black—variations in properties Paternoster, Sydney 156 Patrick, Dr Joseph 170 Patriotic Junta 162 Peachy, S. J. 208 Pelles 82, 152 Peradeniya (Botanic Gardens) 97 Perak 96, 99, 101 Peroxide curing 214 Personal Narrative, see Hancock, Thomas Persoon 25 Peruvian Amazon Co. 151 Peruvian Amazon Rubber Co. 151 Phase compatibilisation 218 Phase separation 219 Phenolic antioxidants 242, 243, 244 Pickle 37, 50, 52, 189 Pietro, Martire d’Anghiera 12 Piperidine in vulcanisation 208
Pitman 200 Pizarro 17 Plantation industry xxix, 85, 96, 97, 98, 99, 104, 143 Plantation rubber 99, 101, 102, 140, 158, 166 Planters from used tyres 267 Plasticised PVC 262 see also PVC Plasticisers 182, 220, 228, 277 general purpose 220 Plasticon 174 Plastics, see thermoplastic elastomers Plastics Historical Society 52, 80 Playground pads 265 Pneumatic tyres xxviii, 66, 73, 144, 145, 224 Pocock, Frank 118 Pok-ta-pok, see ball game Poly(epichlorohydrin) 183 Polyamides 179 Polybutadiene 175, 181, 216, 229 see also butadiene rubber high cis 1–4 181, 184 Polychloroprene 167, 177, 178, 182, 184, 216, 228, 262 Polydimethylsiloxane 183 Polyester 179 Polyester urethanes 186 Polyether urethanes 186 Polyisobutylene 176, 182, 231 Polymerisation xxix, 174, 175, 181 Polymers 169, 173, 177, 181, 186, 207 Polyolefinic elastomers 207 PolyOne Corp. 176 Polypropylene 231, 232 Polystyrene 186 Polyvinylchloride 173 see also PVC Pope Pius X 150 Popol Vuh 6, 9 see also Council Book Poppenhusen and Koenig 235 Poppenhusen, Conrad 235 Post-vulcanisation mechanism 215–216 Power driven machinery 190
Index PPD, see paraphenylenediamines Prain, David 95 President Roosevelt 136 Pre-vulcanisation 214–215 advantages over ‘dry’ vulcanisation 216 mechanism 215–216 Prevulcanised latex 204 Price 261 Priestly, Joseph 22 Processing 46, 47, 190, 274 Product characteristics 245 Proofer’s Song, The 241 Propylene 181, 182 PS 186 see also polystyrene Pseudo blooms, see blooms—different types, causes and mechanisms Puru´s river 146 Putumayo 11, 150, 152, 153, 154, 155, 156, 158, 160, 161, 162, 163 local politics 157–158 location 148 Putumayo Affair 147, 158, 162 PVC 170, 173 see also polyvinyl chloride applications 173–176, 182, 186, 262 Pyrolysis 272, 273 scrap rubber 263 Q group rubbers 183 Queen Victoria 40, 104 and the Congo 119 Quiche´ Maya 7, 8, 9 Quinine 18, 83 Quinones 244 R group rubbers 181, 184 Radiation curing 214 Random co-polymers 181, 185 Rattier & Guibal 55, 56 Read, Henry 151, 160–161 Recapping 264, 265 Reclaimed rubber acid process 261
331
alkali process 261 demand 261 Recycling xxix, 181, 231, 258 cost benefit 260 economics 263 energy requirements 273–275 environmental damage 260 market for end product 263–4 non-tyre rubbers 262–3 possible rubber products 265–272 processes for making rubber chips and crumb 268–269 tyre rubber 263–272 Recycling and rubber—a definition 260 Red Rubber 136 Regrooving 265 Reinforcement of rubber 224, 228, 261, 273 Remolino 153 REP 203 Resilience 213 Retreading 264–265 Retro protection of vulcanisates 245, 249–250 Rheometer 211, 212 Rider Brothers 69, 70 Ridley, Sir Henry N. 94, 95, 97, 99, 101, 102, 143, 168 Rioja 148 River Kasai 125, 130 River Negro 85, 146 Robber barons 108 Roberts, Charles, M. P. 159 Rocca, Benjamin Saldan˜a 154–156 Rolling resistance 229 Roosevelt, President 136 Rot-proof cords 180 Rowlands, John 115 Rowley 208 Roxburgh, W. 232 Roxbury Rubber Co. 30, 31 Royal Botanic Gardens, Kew 77, 83, 84, 85, 87, 88, 92, 93–97, 99, 103
332
Index
Royal Geographic Society 117 Rubber xxvii, 98 Amazonian history 145 and devil worship 13 as a fuel 276 oldest 1 product reuse 265–266 understanding of degradation 239–257 Rubber balls 204 Rubber barons 145, 147, 150 Rubber bottles 13, 16, 49, 50, 188, 258, 260 Rubber buffings 265 Rubber chips—procedures 268 Rubber compound 35, 197, 200, 201 Rubber compounding 197 Rubber crumb 260, 268–272 Rubber doll, The 259 Rubber elasticity 165 Rubber impregnated fabric 192 Rubber items—sacrificial items 3 Rubber manufacturing equipment 46, 189 Rubber People 2 Rubber plantations 77, 83, 84, 85, 97, 98, 99, 101, 102, 104, 105, 124, 140, 143, 169, 275, 276 Rubber products 13, 16, 38, 67, 69, 74, 173, 220, 222, 226, 231, 256, 260 19th C 188 Amazonian natives xxvi, 10 Thomas Hancock 53 Rubber Research Institute of Malaysia 95 Rubber seedlings (summary of travel facts) 95–96 Rubber seeds (Brazilian export laws) 92 Rubber surface degradation 255 Rubber technology 25, 52, 239 Rubber tree 24, 36, 77, 81, 85, 90, 104, 275 see also Hevea braziliensis, Syringe tree, Seringa tree
Rubber waste 50, 258, 272 Rubber wood 274 Rubberised asphalt 270, 271 Rubberised carpet backing 228 Rubberised fabric 34, 73, 189 Rubberised road surfaces—cost considerations 271 Sacrifice xxvi, 6, 9, 26, 27 Santarem 84, 86, 87, 88, 89, 90, 92, 103 SBR 166–167 see also styrene Butadiene rubber Schidrowitz, Philip 1, 204, 214 Scholz, Waldemar 147 Science Museum, London 52 Scottish Vulcanite Co. 235 Scrap rubber—reuse by grinding 260 Second World War xxix, 166, 175, 180, 238 Semi-efficient vulcanisate 213 Semon, Sloan & Craig 249 Semon, Waldo 170–177, 249 death 176 early life 170–172 Kent State University 176 Seringa tree 16 Sequential reactions 248 Seringal 16 Seringueiros 16, 151, 152 Serrano, David 154 Set 247 Seven Hunahpu 8 Shaw, Francis 190, 197, 201 Shearing action 192, 195, 197 Shearing calender 192 Shelf ageing 247, 249 Sheppard, William Henry 130–131 Shiibashi, T. 217 Shoe heels—PVC 174 Shoe soles from used tyres 266 Shoes xxv, 10, 31, 38, 74, 143, 188 Shoes—joke 11 Silica 223
Index Silicone oil 256 Silicone rubbers 182, 183 Silva Gomes, Luis de 146 Silvertown 225 Silvertown Rubber Co. 48 Singapore Botanical Gardens 93, 94 first plantings of Hevea 99 Siphonia elastica 25 SKI3 185 see also IR Skid resistance 274 Slavery 154, 156 in the Congo 112–130 Slaves 81, 143, 154, 155, 156 Slippage 247 Sloan, see Semon, Sloan & Craig Smoking related to curing 214, 215 Solarisation 32, 233 Solvent swelling 167, 213, 219, 250 South American rubber industry, its common thread with African 145 SP 185 see also NR Specimen 66—see nylon 66 Spencer, George 73 Spencer-Moulton 73 Spiller, J. 239 Spreading machine 55, 59, 189 Spruce Richard 81, 82 Sri Lanka 83, 93–97, 99, 107 see also Ceylon SS Amazonas 87, 88, 92 bill of Entry, Liverpool 90 crew records 89 voyages in 1885–6 89 Staining 243, 256 Standard Oil 174, 176, 181 Stanley Falls 118, 124 Stanley Pool 118, 121, 125 Stanley, Henry M. 114–129, 131 early years 115–116 how to deal with natives 118 Lady Alice and Alice Pike 117–119 meets Leopold II 120 railway 120, 123–126, 134 Statistics
333
areas under early cultivation in Sri Lanka 99 Congolese population 1880–1930 140–141 early land usage in Malaysia 102 energy requirements to synthesise and process natural & synthetic rubbers 274 Hancock’s early statistics 75 Leopold’s income & fortune 139 natural rubber production 20th C 166 Putumayo deaths 158 Putumayo, lives vs rubber 163 rubber ex Para´ 1836–72 144 rubber from the Congo 139 rubber vs life in the Congo 141 scrap tyres 262 synthetic rubber production 20th C 166 US rubber production 1939–45 175–176 Staudinger, Hermann 165 Steam carriages 46 Steam-heated platens 200 Stearine 223 Steel 269, 273 Stephenson Reduction Plan 169, 174, 175 Stereo-regular emulsion phase polymerisation 181 Structure 230–232 see also Carbon black—variations in properties Styrene butadiene rubber 166–167, 174, 229 energy requirements for synthesis/processing 274 Sua´rez, Nicola´s 146, 153 Submarine telegraph cables 47, 207 Sulphur 32, 33, 34, 38, 62, 64, 69, 71, 72, 73, 185, 207, 208, 209, 210, 211, 212, 213, 214, 222, 231, 232, 233, 247, 252, 253, 257, 260, 261, 273
334
Index
Sulphur bloom 252 Sulphur chloride 189, 214 Sulphuric acid 247 Surface contamination 252, 256 see also blooms—different types, causes and mechanisms Surgeons’ gloves xxv, 277 SW Silver & Co. 47 Sweetman, Helen 180 Swettenham, Sir Frank 99, 143 Synthetic ebonite 235 Synthetic elastomers 23, 164, 170, 174, 176, 182, 187, 190, 229 Synthetic fibres 179 Synthetic rubber xxix, 163–188 Synthetic rubber production in the 20th C 144 Syringe tree 16, 24, 25 Syringe wood 16 Syringes—Fresneau, Francois 19 T group rubbers 185 Talalay, Leon 204 Talc 30, 222, 223, 228 see also magnesium silicate Tan Chay Yan 101 Tapajos river 86, 88 Tappers 16, 77, 81, 82, 98, 145 life in the Congo 126–128, 135, 141 the Putumayo 151–160 the view of Henry Gielgud 159–160 TARRC, see Tun Abdul Razak Research Centre Tea 97, 98 Teats xxv, 213 Technoflon 183 see also Viton Tenochca, see Aztecs Teotihuacan 9–10 The Mechanics Magazine 79 The Times 130 Thermal aging 213, 246–247 Thermal blacks 225–227 Thermal degradation scrap rubber 263, 269, 272 Thermal movement 165–166
Thermoplastic elastomers 181, 186, 231–232 Thermoplastic rubbers 263 Thiokols 170, 185 Thiurams 209 Thomas, A. G. 251 Thomas, James 69 Thompson, R. W. 66, 144 Through the Dark Continent 118 Tiber 66—see nylon 66 Tilden, W. A. 168 Titanium dioxide 223, 228 Tlachtil 2 see also ball game TNT manufacture 172 Toltecs 9 Top dressings from recycled rubber crumb 270 Torquemada 12, 13 Total energy audit 264 Toys xxvi, 71, 176, 177, 204 Trace metals discolouration/staining 257 effect on ageing 243, 249 effects on vulcanisates 223 Tread wear 225, 229 Trimen, Dr H. 96, 97, 101 True blooms, see blooms—different types, causes and mechanisms Trumbull, Dr 173 Truth—the newspaper 156 Tun Abdul Razak Research Centre 210 Turpentine 20, 32, 48, 53, 54, 59 Two roll mill 201 Tyre reclaim demand 261 Tyre wear 274 Tyres xxv, 173, 174, 175, 179, 223, 225–226, 240, 260, 262, 266–272 Tyres—recyling problems 263 U group rubbers 186 Uhlinger 225 UK Parliament and the Putumayo investigation 159–162 report into Arana 162
Index Ultrasonic devulcanisation 273 United States Rubber Co. 38 Upton, James 143 UV absorbers 248 Valca´cel, Judge Carlos 157, 158 Valco, see Meyer, von Susich & Valco Van Kerckhoven 128 Vaucanson 19 Vicki Baum, see Baum, Vicki Villa des Ce`dres 137 Vistanex 182 see also Polyisobutylene Viton 183 Voltaire 14 Von Susich, see Meyer, von Susich & Valco Vulcalok 173 Vulcanite 38, 66, 232 see also ebonite Vulcanisation 45, 200, 222, 239 and curing 207, 214 chemical process 210–211 chemistry 165, 208 effect of different systems on properties 213 history xxix, 207 new chemicals 208 sulphur/accelerator levels 210–213 theory of develops 210, 212 Vulcanised rubber articles 258 Vulcanising ingredients; differential solubility in blends 217 Vulcanising system 209 Waste management 231 Waxes 257 purpose of blooms 253 Weber, CO 210 Webster, Daniel 40–41 Weiditz 6 Welsh, C. K. 145 Werner Pfleiderer 197 West African Mail 133 West Ham Gutta Percha Co. 47 West Indians 151 Arana’s mistake 156
335
Wet traction 229 White lead 34, 222 Wicherley, W. 95 Wickham, Harriette Jane 85, 86 Wickham, John 85 Wickham, Sir Henry 84, 92, 93, 94, 97, 98, 105 acquires Hevea seeds 88 book of 1908 87 Brazilian official view of the ‘seed snatch’ 92 character assessments 105 family deaths in Brazil 87 his story dismantled 88–92 in British Honduras 103 in Papua New Guinea 104 in Queensland 103 life after 1876 103–107 life to 1876 85–87 marriage 86 parents 85 return to England 104 Willdenhow 25 Williams, G. 168 Williams, James Washington 129, 137 ‘A crime against Humanity’ 130 letter to King Leopold II 129 letter to President Harrison (USA) 129 premature death 130 Willis, J. C. 98 Witchcraft 4, 27 Woburn 31, 32 Woodcock, Alonso 56 Woodcock, Edward 55 Xanthates 209 Xbalanque 8 Xine´nez, Francisco 8 Xmucane 7, 8 Xpiyacoc 7, 8 Yellowing—reasons and mechanisms 243–245
336 Yucatan peninsular 6, 9, 26 Yurimaguas 148, 149 Ziegler, Karl 181 Zinc dialkyldithiocarbamates 209 Zinc dithiocarbamates and blooms 253
Index Zinc mercaptobenzimidazole and blooms 253 Zinc oxide 209, 213, 214, 223, 254, 256, 257, 273 Zinc stearate and blooms 254 Zumaeta, Eleonora 148, 157 Zumaeta, Pablo 149, 150, 157