Environmental Impact of Textiles

Environmental impact of textiles

Environmental impact of textiles Production, processes and protection Keith Slater

CRC Press Boca Raton Boston New York Washington, DC

Cambridge England

Published by Woodhead Publishing Limited in association with The Textile Institute Woodhead Publishing Ltd Abington Hall, Abington Cambridge CB1 6AH, England www.woodhead-publishing.com Published in North America by CRC Press LLC 2000 Corporate Blvd, NW Boca Raton FL 33431, USA First published 2003, Woodhead Publishing Ltd and CRC Press LLC © 2003, Woodhead Publishing Ltd The author has asserted his moral rights. This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. Reasonable efforts have been made to publish reliable data and information, but the author and the publishers cannot assume responsibility for the validity of all materials. Neither the author nor the publishers, nor anyone else associated with this publication, shall be liable for any loss, damage or liability directly or indirectly caused or alleged to be caused by this book. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming and recording, or by any information storage or retrieval system, without permission in writing from the publishers. The consent of Woodhead Publishing and CRC Press does not extend to copying for general distribution, for promotion, for creating new works, or for resale. Specific permission must be obtained in writing from Woodhead Publishing or CRC Press for such copying. Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation, without intent to infringe. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. Library of Congress Cataloging in Publication Data A catalog record for this book is available from the Library of Congress. Woodhead Publishing ISBN 1 85573 541 5 CRC Press ISBN 0-8493-1778-9 CRC Press order number: WP1778 Typeset by Ann Buchan (Typesetters), Shepperton, Middlesex Printed by TJ International, Padstow, Cornwall, England

Contents

Preface

ix

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10

Structure and stability of the ecosystem The ecosystem Life Necessities of life Other species Land hazards Dust Atomic radiation The Earth’s environment Environmental balance The textile industry References

1 1 1 2 4 6 6 7 7 7 8 8

2 2.1 2.2 2.3 2.4

The health of our planet Planetary stability Natural factors Human interference Changes occurring

9 9 9 10 14

3 3.1 3.2 3.3 3.4

The nature of textiles Properties Textiles as engineering materials Principles of textile manufacture Energy

17 17 17 18 18

4 4.1 4.2 4.3 4.4

Textile fibre production Scope of the industry Natural fibre production Artificial fibre production Alternative fibre sources

23 23 23 31 34 v

vi

Contents

4.5 4.6 4.7

Inorganic fibres Microbiologically stable fibres Effects on the planet References

34 37 37 37

5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 5.14 5.15

Yarn production Starting material state Washing Scouring Bleaching Carbonising Drying needs Baling Transportation Opening Carding Blending Combing and gilling Drawing Spinning Noise and dust References

40 40 42 42 44 46 48 48 49 52 53 53 53 54 54 55 59

6 6.1 6.2

Fabric production Traditional fabric production methods Other methods References

61 61 63 68

7 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9

Fabric treatment processes Starting material Finishing categories Mechanical finishing Chemical treatments Other finishes Colouration Pollution aspects Printing Drying and shipping References

69 69 69 70 71 74 81 82 85 87 88

8 8.1 8.2

Use of textiles Primary and secondary production Types of use

90 90 90

Contents

vii

8.3 8.4 8.5 8.6

Normal uses Environmental aspects Household textiles Industrial and medical uses References

91 92 93 94 97

9 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10

Environmental protection Commitment Protective applications Legislation Future prospects Financial benefits Costs Drawbacks Recycling Pollution measurement problems Environmental auditing References

98 98 99 100 101 101 102 102 107 109 109 112

10 10.1 10.2 10.3 10.4 10.5 10.6 10.7 10.8 10.9 10.10 10.11 10.12 10.13

Effects on textiles of natural exposure Influences Degradation Atmospheric influences Radiation Changes occurring Infrared radiation Other types of radiation Mechanical action Mechanical stress in manufacture Mechanical stress in use Prediction of effects Degradative combinations Magnitude of textile environmental damage contributions References

115 115 115 117 119 121 122 122 123 126 127 128 130 134 138

11 11.1 11.2 11.3 11.4 11.5 11.6 11.7

Thermal exposure Intensity Static drying Stenters New equipment Problems Novel approaches Flammability References

139 139 140 141 144 144 145 146 151

viii

Contents

12 12.1 12.2 12.3 12.4

Chemical and microbiological attack Reagents Fibre type Planned attack Microbiological attack References

152 152 153 154 155 160

13 13.1 13.2 13.3 13.4 13.5 13.6 13.7 13.8 13.9

Protection of, or by, textiles from environmental damage Aspects Maintenance Degradation during use Chemical treatments Protection of humans Modern developments Non-clothing protective needs Protection for the environment Desirable properties References

161 161 162 162 163 163 166 169 171 174 175

14

Conclusions

178

Appendix Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 Section 7 Section 8 Section 9 Section 10

Cotton scouring with enzymes Wool scouring with enzymes Bleaching with peroxide Sizing and desizing Pollution reduction in dyeing Medical applications of textiles Textile filters Sporting goods and other uses Effluent treatment Recycling References

Index

183 183 187 189 190 191 194 196 196 197 201 203 207

Preface

A piece of clothing, or any other textile article, is a very difficult and expensive product to manufacture. But not only does it cost a lot of money – our usual way of estimating how much inherent value should be placed on an item – it is expensive in another, more important, way, one which might conceivably make even money ultimately redundant. It harms the environment, the protective envelope under which we all live. If the environment is destroyed, then so are we. Let me hasten to add that the manufacture of textile goods does not provide the only, or even the most severe, stress to which our planet is subjected. There are many other products that can damage the Earth’s well-being, but the textile industry is often blamed (perhaps unfairly) far more than it deserves. The reasons are, I believe, two-fold. First, textiles are a widespread, virtually universal product, familiar to practically the entire population of the world. Second, the kind of undesirable effect that textile manufacture has on the planet is often very tangible. We see dyestuffs colouring rivers or black clouds of smoke rising from the chimney over a finishing plant. We hear the cacophony emerging from a weaving shed, twisting room or spinning mill as machines shriek noisily at us. We see the remnants of discarded clothing littering a street or rubbish dump. We see diesel trucks belching fumes as they are driven into or out of a textile plant to deliver raw materials or shipped goods. So we need to investigate the actual relationship between textiles and the environment. It is important to note from the beginning that this investigation has a double-edged meaning. The manufacture and use of textile goods can have an adverse effect on the environment, but the environment can also have, in an ironic twist, an adverse effect on textile goods. The former of these effects we normally lump together under the term ‘pollution’ and the latter we describe as ‘degradation’ of the materials. Before we can start our investigation, though, we need to be clear about what we mean by the environment. All the evidence that I have observed on the subject leads me to believe that there is not really any widespread understanding of what is actually meant by this nebulous term. We hear references to the social environment, or to the physical one, or to other such differentiations of the word into a range of individual aspects. At the outset, then, I intend to define what aspects of the environment I shall be including in this book. ix

x

Preface

In simple terms, what I hope to do is to examine what effects all phases of textile production and use have on the Earth around us, from growing or making fibres to discarding a product after its useful life has ended. I shall look at the physical environment, including the air, the water and the land. I shall also look briefly at the biological environment by considering what happens, as a result of manufacture, to other species on the planet, as well as to human beings. The effects I will be considering are not only those on our bodies, but also on our minds. The social environment as it impinges on our psychological, physical and physiological comfort will be part of the discussion, as also will our financial well-being. In short, I regard the environment as encompassing all aspects of every part of our lives. To the best of my knowledge, this comprehensive approach has not been undertaken before and has never previously been associated with textile production and use. In a sense, then, this book is a pioneering one, yet it is not strictly a new one. All it does is pull together a wide range of examples drawn from a diverse collection of sources and integrate them to form a new and coherent set of ideas. If it informs, educates or amuses you in the process, I shall be delighted. My approach might seem odd for a book that is supposed to be about textiles. I intend to deal first with the environment itself in some detail, to ensure that my starting position is understood. In this way I hope to persuade you to accept the truth, as I believe it, of the situation we, as a species, find ourselves in today and what the textile industry has contributed to this position. I intend to be entirely honest so that, if I feel that the industry is to blame for some harmful aspect or condition, I shall lay the blame squarely. Conversely, if I feel that the textile community is the victim of accusations that are giving it an undeserved reputation, or if some of its practices are not receiving the praise that is due to it, I will be equally conscientious in pointing out these facts. For this reason, I shall begin the book with chapters dealing with our fragile environment and our dependence, together with that of all the other species occupying the Earth, on its well-being. I shall examine the conditions needed to ensure a healthy, stable planet and look at what any deviation from these conditions can do to a range of species. I shall then take a closer look at how the human race, in general, has brought about undesirable changes in the planet’s health. Aspects of resource depletion, pollution and energy use will be covered. In all of these areas, to keep the focus on textiles, I shall try to find suitable examples of where the industry fits into the overall picture. Then, in the rest of the book, I shall focus more directly on textile matters. I hope first to provide a complete survey of how developments in the industry and consumers of its products have affected the planet’s health in the past. Then I will look at modern solutions that have often been proposed by ‘experts’ in areas other than textiles but adopted by the industry in the hope that some alleviation of problems can be achieved without sacrificing high textile production targets. After showing that this aim is unrealistic, I shall discuss the real ways in which the

Preface

xi

industry is responding to the challenge of keeping our planet healthy and conclude with my view of the future. In this, I hope to persuade readers that the planet can indeed be saved without abandoning all our cherished lifestyle, but that we need to be vigilant in every step we take, as individuals as well as representatives of a great and essential industry, to ensure that unfair blame is not allocated to us by outside observers. Each chapter will be divided into sections allowing subjects to be kept separate and cross-references to a specific topic to remain simple. I hope to engage both the general reader who is interested in the subject as a whole and the specialist reader who would like to follow in more detail the particular points on which I focus. With this in mind, in some chapters, I will only deal with the highlights of a topic, but will make reference to further relevant work in the Appendix, where the more technical aspects are summarised. There, I will provide references, to enable readers interested in each specific point to obtain more detailed information. Categories of pollution production, as listed in Table 1.1, will be identified by an asterisk, in parentheses and bold, italic type. My ultimate aim is to address and correct some of the fallacies shared by many people, both within and outside the industry, about the real effects of textile manufacture and use on the environment. If I am successful, we should see a more caring, clean and respected industry (which will also, almost certainly, be a more profitable one) emerging in the future.

1 Structure and stability of the ecosystem

1.1

The ecosystem

What does the term ecosystem actually mean? One dictionary gives the meaning as ‘a system formed by the interaction of a community of organisms with their environment’1 with an encyclopaedia giving the proviso2 that the assembly of organisms can be of any size and level, provided they are all free to interact together in a single complex whole and are in close relationship with the environment. In a sense then, all life, everywhere on the Earth, can be seen as a single ecosystem, or our planet’s entity can be divided into a range of ecosystems. Typical examples of such subdivision could include, say, an ocean, or the atmosphere, or a tropical forest or an urban city, and all of them would then be combined together with a host of other ecosystems to form the biosphere as a whole. What these all share in common is that they are a location where life is supported and where all forms of that life are living together in equilibrium.

1.2

Life

Next, how is ‘life’ defined? Most people could recognise a dead body when it appears on the television screen, so this familiar scenario can be used to focus attention on the differences between an ‘alive’ and a ‘dead’ state. The investigating officer can be recognised as representative of the living and the corpse is definitely a dead object. Underneath the corpse, however, is a myriad of creatures, existing in a wide range of shapes and minute sizes, some too small to be seen by the naked eye. There may, for instance, be worms, insects or vegetable matter. All of these would be unhesitatingly accepted as examples of life, but there will also be bacteria and perhaps lichens or fungi. Now, the borderline between living and non-living creatures is less certain. Further down the scale are the amoebae, washed out of the victim’s bloodstream; where do these belong in our interpretation of life? And what about the fragment of yeast, left by a final glass of wine residing in the victim’s stomach; where does that fit into the grand scheme of things? 1

2

Environmental impact of textiles

Most people would agree that the sheep that provided the wool used to make winter garments worn by the two human examples, and the cotton plant that provided the raw material for their underwear or shirts, were alive. But what about the wool or the cotton fibres after they had been harvested? And, if we accept the validity of the well-known Gaia Hypothesis3, is the Earth itself really a living creature, holding its breath to deceive us into thinking it is not alive and lurking in wait to send us all to destruction as soon as we become too much of a nuisance? In scientific terms, many of these (with the possible exception of the fibres and the entity of the Earth) are examples of living organisms. For the purposes of this book, whether or not we agree to accept the Gaia Hypothesis, the whole planet, together with its atmospheric envelope and everything inside that envelope, will be considered as a ‘living’ ecosystem. After all, if any portion of this entity is destroyed or ‘killed’ by any action of ours, then the entire system is likely to go into a tail spin and end up as a lifeless hulk, along with any residual bits and pieces of all its inhabitants, including us.

1.3

Necessities of life

For a healthy existence, there are certain necessities that must be widely available. Not all the ‘living’ parts of the ecosystem require all of them and some ‘living’ units may be able to survive without any of them, but the vast majority of this planet’s inhabitants need four commodities for their survival. These are, in order of frequency of need for humans and other higher animals, clean air, clean water, food and protection from external or internal ambient conditions.

1.3.1 Air If human beings are considered to be the typical example of the most developed of the inhabitants of the planet, we can examine each of the necessities of life in turn as they relate to humans. The oxygen contained in air is needed to allow the cells of the human body to effect its continuing existence. Blood carries oxygen to remote parts of the human body where it oxidises impurities and transports the products of this reaction as waste to the lungs (or other appropriate places) for removal. In order to survive, oxygen is needed on a more or less continuous basis; in its absence, survival will only be maintained for about four minutes without experiencing irreversible brain damage and clinical death will follow in about six minutes. Unfortunately, the air has to be pure. Nitrogen can be tolerated as a diluent for oxygen, and to some extent carbon dioxide, but in modern times there may be other constituents of air that are much less acceptable to the human system. If there are toxic materials or an excessive quantity of carbon dioxide present, then human beings are likely to succumb to the hazards of these impurities and to suffer illness, or even death. Other lower organisms in the biological kingdom share this

Structure and stability of the ecosystem

3

regrettable inability to survive in a poisonous atmosphere, but there are some recipients who might thrive on such compounds. The most obvious example is plant life, which absorbs carbon dioxide and converts it into oxygen, replenishing the supply of this vital (to animals) gas. This happy coincidence will be discussed further, later in the book. There are also certain bacteria that can be trained to gobble up oil slicks or other forms of pollution when an emergency spill takes place.

1.3.2 Water The second need is for water, a substance that constitutes over 90% of the human body. Again, the water must be pure; the slightest trace of bacterial contamination can bring on a marathon attack of various illnesses that manifest themselves as vomiting and diarrhoea. The cause of this reaction is a protective mechanism that reacts to get rid of the offending impurity as quickly as possible, especially if the immune system involved has not developed natural arrangements to give it the ability to deal with the contamination. The need for the actual water, though, is much more critical. Human beings could survive the bacterial invasion, and do so on a regular basis, but cannot survive the absence of the water that carries these bacteria. The human body consists of millions of cells, each of which includes water. The 90% figure mentioned above results from water being taken up by these cells and combined to make some form of chemical compound that is an essential component of the specific cell or of its ability to function. Cells are living organisms, so change constantly. Impurities arising as a result of their operation are removed, usually in aqueous solution, so the water that washes away the waste products has to be replenished to allow the cell to continue living. A fresh supply of water has to be available for the cell to recharge itself and this is where the need for water arises. Without water, the cell would dry up and die, then be rejected as waste in its own turn by the body. Obviously, if there is no water, there can be no healthy cell replacement, and if every cell is rejected as waste, there will not be much left of the body to keep life ticking over. One small consolation is that the person would not know much about such a disaster, because brain cells, which require replenishment very frequently, are lost early on in the dehydration process and madness quickly sets in if water is denied. Lack of water can drive human beings insane in a matter of a few days. Death does not take much longer.

1.3.3 Food A human body needs vital chemical substances to sustain its existence. Nutrition is the process by which the body takes up these chemicals and converts them to muscle, fat, blood, energy and all the other important bits and pieces that are needed to continue functioning in a healthy manner. Without food, we become

4

Environmental impact of textiles

angry, impatient, listless and eventually unable to sit up and retain an awareness of life around us. Most human beings can survive for weeks without food (as long as water is available) before succumbing to starvation. People can also survive for years without adequate nutrition, as evidenced by the grim pictures shown on our television screens from time to time when famine strikes in some of the less fortunate regions of the planet.

1.3.4 Protection The last crucial need is one that humans have continually and considerably refined over the last few millennia. As primitive creatures, our forebears were able to survive in the wild, just as animals do today, with little or no help from artificial (i.e. non-natural) sources. In modern times, that ability has been lost, mainly as a result of our determination to cosset ourselves with all kinds of luxury. The consequence is that now humans cannot survive without some form of protection. This is of two broad types: shelter as a shield from other forms of life and from the elements and textiles as protection from these same elements and from the harmful effects of abrasive or wounding contact with objects that are encountered throughout life. The textiles also provide mental protection in hiding our bodies from the gaze of other people, a subject that will be discussed again later. In both types of protection, the primary purposes are to keep the body’s integrity intact and to allow its built-in mechanisms to remain functioning without unduly overloading them. We continue to exist and move about because our hearts pump blood around the body, our gastrointestinal systems convert food energy to a useful form, our thermoregulatory systems keep our bodies within a satisfactory temperature range, our cardiovascular systems continue to supply fresh oxygen and remove excess carbon dioxide and our muscles continue to operate without getting wasted away or suffering from spasms. Without any of these advantages, we would run a grave risk of dying. One of the purposes of textiles is to support the body in retaining them.

1.4

Other species

What can be said of animals and plants? The larger animals that provide us with textile fibres, such as sheep, goats, camels, and so on, have similar needs to our own. They need air, water and food to survive. They are, though, not as dependent as we are on pure water, because they are able to tolerate pollution of various kinds without harm. They generally also do not need external protection, since they already have warm coats (which are, of course, the bits that humans take for textile raw materials) to fill this role. Smaller creatures that produce textile fibres, such as silkworms or spiders, are even less demanding in their vital requirements, though the silkworm produces poorer quality fibres in the absence of an optimum diet. The plants that are used to make our textiles will thrive to some extent even if

Structure and stability of the ecosystem

5

Table 1.1 Categories of pollution production Code

Type

Emission

Effects

A-1 A-2 A-3 W-1

Air Air Air Water

Carbon dioxide Toxic gases Smoke Heat

Greenhouse gases Poisoning of species Visibility loss Fish stress

W-2 W-3

Water Water

Colour Toxic liquids

L-1 L-2

Land Land

Salts Toxic solids

L-3

Land

N-1

Noise

N-2 N-3 V-1 V-2 V-3

Noise Noise Visual Visual Visual

Microbiological hazards Moderate HF and LF Loud HF Loud LF View obstruction Discarded garbage Smog

Typical example

Burning wood Burning rubber Tenter exhaust Power station effluent Potability concerns Dyehouse effluent Poisoning aqueous Chemical plant species effluent Plant growth stunted Ice salt Food chain poisoning Agricultural chemical discharge Disease or death Manure discharge

Psychological nuisance Deafness Building damage Aesthetic loss Landfill overload Limited visibility

Rock music Spinning frame Weaving shed Hoardings Textile waste Coal fires

HF and LF represent high and low frequency, respectively.

adequate conditions are not provided. Thus, cotton, linen or bast fibres will continue to grow even in poor soil, though the fibre quality is, once more, lower in the absence of good nutrition. Like all plants, they will benefit from excess carbon dioxide, even in amounts that would be fatal to human beings. In many cases, too, pollution of certain kinds may actually be advantageous. Manure, for example, is highly beneficial for a plant to thrive, in direct contradiction to its toxic behaviour as a source of the potentially dangerous (to human beings) E. coli organism. Where they lack endurance is in the matter of temperature and light tolerance; plants will die in cold or dark ambient conditions that would be accepted with little trouble by human beings or other animals. There are some chemical compounds that are harmful to plants as well as to animals. These substances will be brought into sharp focus in the later parts of this book. They can be loosely classified into various categories, as shown in Table 1.1, where they are grouped according to the harmful effects they produce in different living species. There are, naturally, many more substances than are shown in Table 1.1. The list is intended only to illustrate the type of harmful behaviour that can be produced. Later in the book, one or more of these types will be referred to wherever a compound that is environmentally undesirable in some way is derived from a textile-related activity. The occurrence of pollution will be identified by an asterisk

6

Environmental impact of textiles

with the specific category code placed in parentheses, bold-faced and italic (see Table 1.1). Thus, a toxic gas poisonous to any species, whether animal or plant, will be referred to as (* A-2) in the text. The need of flora and fauna for a non-toxic environment is the root cause of the importance of cleanliness in air and water. Even if the contamination is a very small proportion of the air or water, it can still be harmful. To recognise the truth of this statement, imagine breathing a sample of air, or swallowing a glass of water, containing an almost insignificant quantity of cyanide. Thus, both the nature and the amount present of a pollutant should be taken into account in determining the potential harm of each substance. This approach is used by governments in arriving at legislation defining the permissible level of contamination of harmful substances, as will be discussed in a later chapter. Amounts exceeding these levels may not be fatal, but are likely to cause sickness in a species susceptible to their harmful effects. Other consequences that should be considered may include genetic changes, fertility loss, lower survival rates or lifetimes and the onset of diseases that would not exist in the absence of the contaminant.

1.5

Land hazards

It is not only in the air or water ingested that caution has to be observed. The land itself can also be a source of harm to those living on or feeding from it. Toxic agents in water may be washed into the soil and find their way into growing plants. Harmful substances in the air may be deposited onto the ground, or may be absorbed by components of the soil, again being transferred into plants. The harmful chemicals will eventually be washed out of the soil and into drinking water supplies, so it is virtually impossible to take adequate precautions against the unpleasant consequences of land pollution. The effects of this movement are that the toxins enter the food chain, either via plant absorption or after animals have drunk them. Eventually, as a result of the predator–prey relationship, they end up in the bodies of many other species, including our own, where their adverse effects will ultimately make themselves known in the all-too-familiar forms of food poisoning. Aquatic species, whether fish or plant, are particularly rapidly susceptible to this type of harm, since they are totally dependent on water (which may be heavily contaminated by the chemicals washed off from the land at an early stage of the distribution process) for their successful functioning.

1.6

Dust

We should not ignore various miscellaneous types of activity that can prove harmful to the planet or to its inhabitants. The first of these is the dust that is present everywhere, in large or small amounts. Dust is formed by microscopic-sized particles produced when some larger object breaks down. The larger object may be a soil crumb, or the skin on an animal’s body or portions of a plant. In the context

Structure and stability of the ecosystem

7

of this book, it may be the textile fibres being processed in a mill or the solid residue after a substance (such as a starch or finish) has been applied to a fabric. Dust, of whatever kind, is responsible for a number of ecological problems. If its origin is soil, then the disappearance of that soil means that plants dependent on it will not grow as well. If it is from an animal or plant, then the effects of its presence may include setting up allergic reactions in other creatures (including humans) nearby. If it is from a textile fibre, or other substance in the mill, then workers in the vicinity may suffer from serious illnesses, in the form of severe lung diseases from breathing it in too high a concentration. Dust can also cause deterioration of nearby objects, either by abrasion (as on buildings, for example) or, in the textile case, by producing a dirty product or by bringing about wear in a fabric structure or machine component.

1.7

Atomic radiation

Atomic radiation should be included in this survey of environmental contaminants. If a radioactive substance comes into contact with a living cell, the radiation emitted can bring about harmful changes in the structure of a cell. These may confer on cells an inability to divide in a healthy manner, or (for larger organisms) prevent the organism from reproducing correctly. The result may be unhealthy offspring, a failure to operate correctly or, in the limit, an inability to survive. Even low-level radiation, such as that present in equipment designed to measure thickness, evenness or static electricity in textiles, is now suspected of being dangerous on long exposure, so precautions have to be taken to shield human beings from its presence. Power stations are an obvious modern source of atomic energy. The accidents that have happened internationally over the past few decades are a constant reminder of the dreadful destructive power of atomic radiation.

1.8

The Earth’s environment

It would not be ethical to omit the Earth’s own environment from our list of origins of problems. Virtually all the harmful sources that have been specified as being risky in this chapter occur in nature. The Earth is constantly being bombarded by cosmic radiation from the universe. Dust storms arise in dry seasons. Volcanoes spew out toxic fumes. Forest fires, started by lightning strikes, increase the concentration of toxic chemicals and of carbon monoxide or carbon dioxide in the air. Water is contaminated by animal excrement. Natural sources of radium or uranium bring about genetic modification in animals living near them. Solar radiation can cause skin cancer in animals or loss of water from natural habitats that provide shelter, food and drink.

1.9

Environmental balance

Environmental balance is delicate and sensitive. Without human interference, the

8

Environmental impact of textiles

Earth has, over the millions or billions of years of its existence, managed to bring about a stable equilibrium, so that all natural creatures can survive in harmony with the planet. Unfortunately, the presence of humanity, especially since the days of the Industrial Revolution, when mechanical aids were found that enhanced the meagre powers of human beings, has changed matters in drastic ways. Nature can now be overridden and harnessed at will. We can take all we want from the planet and pay no heed to the effects that our behaviour might have. Or so we used to believe. Now, though, there are signs that the planet’s ecosystem is responding in a way that bodes ill for the future and even for the survival of human beings on Earth. Environmental harm is increasing. The adverse effects that human behaviour can have on nature and, in the limit, on humanity itself are beginning to be noticed. Indeed, some scientists believe that we are on the brink of causing such adverse reactions and that we are already on, or possibly past, the threshold of destroying our prospects for survival. We appear to be happily acquiescing to our own self-destruction; we rush to buy the latest car or computer or furniture or household appliance or other such gimmick long before we need to do so for utilitarian purposes. Our motivation is often purely to display status or wealth, not taking account of the enormous environmental costs incurred.

1.10

The textile industry

In this headlong rush towards self-extinction, the textile industry, because of its major and ubiquitous presence on the Earth, must share some of the blame. The exact amount of its responsibility has never been established (and, indeed, may be impossible to establish). Thus, the first aim of this book is to identify which textile processes are harmful to the health of the Earth and to arrive at an estimate of the extent to which their contribution may be guilty. The second aim is to attempt to judge how much of the harm being done is fairly attributable to the textile industry and how many of the accusations levelled against it are unfair. In the following chapters, the textile production process will be examined, stage by stage, comparing the textile industry briefly with other industries with respect to environmental harm. It will then be shown how the environment itself can turn the tables by being harmful to textile goods. By the end of the book the reader should have been provided with a factual and realistic assessment of what problems are associated with textiles and how the industry, or consumers, can help to reduce them.

References 1 Fleamer, S.B. and Harch, L.C. (eds), Dictionary of the English Language, 2nd edn, New York, Random House, 1987. 2 Parker, S.B. (ed), Concise Encyclopaedia of Science and Technology, 2nd edn, New York, McGraw-Hill, 1978. 3 Lovelock, J.E., Gaia: A New Look at Life on Earth, Oxford, 1979.

2 The health of our planet

2.1

Planetary stability

Now that what factors constitute a stable ecosystem have been examined, the factors that maintain stability and, if stability is not maintained, what factors bring about perturbations in the environmental equilibrium that disrupt the desired state can be addressed. The first point to make is that any equilibrium is temporary in nature. We live on a planet that is doomed. Even if we were not and had never evolved, the Earth would not survive for ever. It may take a long time to disappear all on its own, but its disappearance as we know it will take place in due course. The sun, like all stars, will either expand or shrink before reaching its final state of oblivion. Depending on which of these two takes place, the Earth will either be swallowed up (with everything on it charred) or be lost to outer space because gravitational attraction can no longer keep it in thrall as a planet. In that case, it will become just another dead piece of rock floating in space. The Earth, moreover, is limited in its ability to support life and no miracles are available to change this, either in the short or the long term. The demise of the dinosaurs provides proof that no species can expect to survive for ever. The balance that allows the Earth and all its inhabitants to continue to exist is a very delicate one, established over aeons of time. It involves an equilibrium between all the elements present here, especially the air, the water and the land, which has been achieved by natural processes too complex to consider in any detail here, but which have brought about the miracles of planetary stability and life. If an imbalance occurs in the equilibrium existing on Earth, then survival of more than just people can be jeopardised. Unfortunately, imbalance can arise from natural causes, as well as from the habit of humanity of inflicting on the planet the kind of interference that is the subject of this book.

2.2

Natural factors

As can be seen from the examples introduced briefly in the previous chapter, there 9

10

Environmental impact of textiles

are many natural factors than can disturb, or even (in the course of millennia) destroy completely, the stability of the planet. Geological and fossil records show that, over the long period since its creation, the Earth has only been able to sustain recognisable life forms for a minute fraction of its existence. The basic structure of the planet has been ripped apart many times by natural sources of change that include plate tectonics, volcanic eruptions, solar radiation and, more recently, the existence of weather variations. The former two bring about massive changes, causing continents to shift and mountains to be lifted or destroyed. Solar radiation may cause droughts that can alter the appearance of the countryside, changing it from green to brown, and can initiate melting of the ice caps, with severe flooding of the land as a consequence. Extreme weather conditions, where excessive amounts of rain fall or winds blow, can also produce flooding capable of washing away trees, removing topsoil or bursting the banks of rivers to redefine the landscape. Even relatively small amounts of rain are capable of washing away topsoil, reducing plant growth, leaving the land more barren and, once more, changing the face of the Earth. The sun has other potentially harmful side effects. Cosmic, ultraviolet or infrared rays can accelerate changes in the process of mutation, causing organisms to become modified at a far greater rate than would normally be expected on theoretical grounds. Protective arrangements are in place to prevent some of these changes, consisting of such checks as the filtering effect of the atmosphere or the compensating factor of tree growth for volcanic gas emissions. Ever since they have evolved, animal and plant species have acted as prey or predator for each other, maintaining numbers of each type of creature at an approximately constant level. Chemical reactions (the neutralisation of excess acidity by the solution of limestone, for instance) keep the Earth’s soil in a state that will permit plant growth to continue. All of this means that the Earth’s environmental balance is in an extremely delicate and sensitive state.

2.3

Human interference

Sadly, one group of the planetary family does not seem to fall in with the system of checks and balances that should keep things plodding along happily; human interference has constantly upset this ideal situation. As a species, we have interfered with nature virtually since the day we began to exist. Our entire aim has been to adapt the world around us to enhance our own stature, comfort, wealth or other state that is perceived to be desirable. Of the myriad reasons why we carry out such changes, many depend on some form of textile assistance. These reasons should be carefully examined in preparation for the investigation of textile importance in environmental changes. They can be broadly categorised into three distinct types: survival or protection, war or weaponry and desire for possessions.

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2.3.1 Survival First and probably most obvious is the matter of survival. Animals are content (or so it must be assumed) to live their allotted life span without any effort to prolong it. This is in direct contrast to the human animal. If we can, we will prolong our lives to the last instant, often after natural death should have taken place, and have always had the desire to do so. Our distant forebears developed tools to defend themselves against animals of superior speed and strength. They banded together to outwit prey that would otherwise have escaped, leaving the human beings without food. Once the food was killed, they dragged it home to their kinsmen with the aid of twisted strands of grass, vines or other units that formed the earliest ropes (and probably the earliest true textiles). The only animals they could not easily defeat were those too small to be seen, like bacteria, or those of comparable size and intellect, other human beings. Against the former, they began to practise simple medicine, using the Earth’s resources to produce healing foodstuffs, drugs, balms or ointments. They also used textiles in the form of primitive cloth coverings that kept a wound clean to aid in the healing process. As time passed, they developed means of protecting themselves against dangerous sources of infection, often by adopting textile structures to prevent damaging contact with sharp rocks or other surfaces. Today, we use medical technology to protect us against disease by means of inoculations that have a history dating back to Edward Jenner in the 17th century. If this fails, we try, with an intensity that has accelerated enormously during the last 50 years or so, to conquer the disease by using cures that have slowly evolved since ancient times. If even the drugs fail, surgical intervention may be attempted, dating back at least to Ancient Egypt and evolving slowly in distinct steps since that time. Finally, if surgery is not immediately effective, a patient may be attached to machinery that takes over completely the body’s functions, so that the person can stay alive indefinitely in a state of suspended life. In a modern hospital, textile products are omnipresent, appearing as implants, tissue engineering, hygiene and health care products, protective covers for wound operation sites, bandages, uniform clothing, bedding items, operating room gowns, packaging for surgical instruments or in a host of other applications.

2.3.2 Conflict In the second broad category of how humanity has changed the environment, and in the face of competition from each other, human beings have adopted the art of fighting, aided by the evolution of weaponry. The earliest weapons, made of flint, took a long time to prepare, so fatalities must have tended to be less numerous. Human ingenuity then brought about improvements in weapons by the development of newer materials, such as copper, bronze and, ultimately, iron. Protection against some of these could be achieved by means of clothing, so the techniques of

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Environmental impact of textiles

textile production evolved alongside those of attack against animals or human beings. It has always been the author’s contention (though it is unlikely ever to be proved) that skill in making textile materials is the major, or even sole, reason of the survival of any specific group of human beings. For instance, a clan using the optimum size of spinning whorls would probably defeat one using whorls of inferior size. The reason is obvious; an optimum whorl produces a better (that is, stronger) yarn because it provides better twist, evenness and fineness. If the yarn is better than that of your rival, then so is the fabric. If the fabric is stronger, then two results inevitably follow. First, it will give better protection, allowing the wearer to enjoy an increased chance of survival in combat. Second, it will not need replacing as often, which means that the people spinning the yarn and weaving the cloth can devote the time saved to other tasks, such as food gathering or child care, that will aid the survival of the clan. In our own day, and at close quarters, we have devices that can injure or kill an opponent by a simple movement of a finger on a trigger or button. We have weapons that can destroy our enemy at a distance, even as far away as the other side of the world. These weapons can be attached to vehicles that can cross rough terrain, travel on top of the sea, fly through the air or even venture outside our Earth’s atmosphere before returning to deliver their burden of death. Once again, textile products support these activities in the shape of uniforms, parachutes, camouflage, webbing, seat cushions or other aids to enhance the effectiveness of the battle unit.

2.3.3 Possessions But survival and protection are not the only aims of human existence. Another powerful driving force is the desire to acquire and keep possessions or goods. Since about 7000 BC, when the first civilisations appeared, human beings have been concerned with ensuring that their possessions stay with them as long as they are alive. On their death, apart from the grave goods buried with them as necessities for their comfort in the afterlife, all their possessions had to be passed on to their legitimate offspring to be kept as a part of the wealth of their true descendants. Anthropologists assure us that modesty, the refusal to expose the human body to other people not permitted to view it, began as a means of preventing illicit sex between the wife of one man (her ‘owner’) and another man, so helping to ensure that any child born to the woman did indeed have her ‘owner’ as its father and could inherit his wealth. With the passage of time, this characteristic for acquiring goods, which modern humans tend to equate with status, has become so entrenched that we now clutch fiercely to all we own. Despite our protestations to the contrary, our laws, religious beliefs and social standards do not regard all people as being equal. We happily heap adulation on the chosen few who have obvious wealth, even though that wealth may be built on what many people would regard as spurious worthiness.

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This wealth has to be displayed to all and sundry, and one manifestation of this is the wearing of elaborate, conspicuous clothing made from the richest cloths and the most up-to-date fashions, just to let people know that we have, indeed, acquired ‘eminence’ in the world. At the same time, we casually ignore the plight of millions of our fellow creatures who are on the verge of extinction because they have insufficient food, or water, or money for medical supplies. The need for possessions is not confined to individuals. Countries or regions, too, can exhibit an acquisitiveness that can be harmful to our planet. Disputes flare up on a regular basis over land, often of such poor quality that it seems pointless to bother about. Access to water, or the rights to extract oil, or coal, or gold and other precious metals, or diamonds, or a whole host of similar valuable minerals, are also frequent causes of disagreement between nations. In our pursuit of the wealth represented by these displays of ostentation, we almost invariably make use of textile products. The protective clothing worn by prospectors or workers in hostile climates, the cloth used in filtration processes to extract or purify the minerals, the tarpaulins covering the area or sheltering examination sites; all of these are examples of textiles that simplify, or sometimes even make possible, the extraction of the minerals. So too are the uniforms and camouflage of the armed forces whose presence is necessary to defend the land once it is annexed in order to keep possession of it.

2.3.4 Curiosity We must not forget the other related acquisitive human trait of curiosity. From their first days, our distant ancestors had an urge to investigate and to explore. The earliest human migrations, spreading the new species over the entire surface of the globe, may have been the result either of curiosity about new terrain or a need for self-preservation in the fight for scarce food resources, but later movements were certainly motivated by inquisitiveness. From explorers looking for new markets or new routes to existing ones in ancient times and in the age of discovery that took place principally in the 15th to 19th centuries, to the modern family going abroad for a holiday, human beings have been driven to spread their presence far away from their place of origin. Once again, textiles in the form of clothing (for personal wear or for trading), sails, or tents, or seating and tyre cords in transportation, have played a vital role in ensuring the success of these excursions. Indeed, without them it is entirely possible that our species would never have survived the rigours of the inhospitable climates they must have met on their early migrations, so that it can be fairly claimed that we owe our very existence to these ubiquitous materials. Our curiosity does not end with travel around the planet. We are now exploring parts of the universe outside our planetary limits and in the not-too-distant future we will probably begin to embark on journeys beyond our own galaxy. For all of these pursuits, textiles have been called into service. Space suits, isolation garments,

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Environmental impact of textiles

filter fabrics and other such refinements can be added to the list of uses already summarised. We also explore the Earth about us in ever more increasing detail, from the plants or animals that surround us to the minute particles from which they and we are made. We extend our enquiries into the very bodies, or even minds, of our own species, trying to discover what makes us work. In the immediate future, it will almost certainly be possible to make a copy of ourselves, once we have overcome (or ignored) the ethical scruples we have that deter us from creating life by artificial means. Textile structures are often used as a framework for culturing replacement organs and body parts, so may well play a significant part in prolonging life and increasing the planet’s population burden. In all of these many characteristic traits of modern human existence, our motivations closely reflect those of our ancient ancestors, enabling the route by which we have arrived at our current attitudes to be easily traced. One issue that will be explored in the rest of this book is the effect that all this activity has had on the health of our planet, and what can still be done (especially in the context of textile production or use) to keep it in as healthy a state as possible. In general, there are two overall planetary problems brought about by the consumption created by our determination to survive, enjoy luxury and investigate our world. They are, respectively, the depletion of resources and the production of pollution.

2.4

Changes occurring

The changes occurring when resources are used up by our activities may be inert or damaging ones. It is not particularly important for the future of the Earth, for instance, if all the coal or oil is extracted from the ground. It may well be important for the survival of humanity, which is what is usually meant when the survival of the Earth is discussed, but the presence or absence of these particular materials will not affect the survival of the remainder of its inhabitants. On the other hand, if the resource used up is oxygen, or pure water or the vegetative cover, then a different conclusion would have to be drawn. True, the barren planet would continue to rotate around the Sun (until that source of energy disappeared), but the remainder of the living ecosystem would be altered so drastically that no stable conditions could be expected to remain. There may be a reinvention of evolution once the system had stabilised again, but whether that evolution would bring about the existence of animals or human creatures is by no means certain.

2.4.1 Pollution The other major effect, that of pollution, can sometimes be a more serious matter. When unwanted items are discarded on the surface of the Earth, their presence there tends to be forgotten. The end result of their being jettisoned, though, may be harmless or serious, depending on their nature. In the main, any substance derived

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15

from a natural source, without chemical treatment in its production, will bring about no physical harm to the Earth (though it may be objectionable to view), but a chemical treatment will, on the whole, make the discarded object harmful. Thus, a piece of wood thrown into a field will fairly quickly decompose back to organic products that can be absorbed into the soil with no ill effects, but a piece of plywood or paper made from wood that has been treated with resins or bleaching and printing compounds can contaminate the soil (* L-2) (see Table 1.1 for explanation of codes) with the resultant decomposition products. Any chemical substances thrown away can have a range of undesirable environmental effects. First, they may leach into the ground where they are dissolved into the subterranean water and hence reach streams, rivers and springs, from which animals (including humans) get their drinking water. A steady diet of these compounds is not recommended for healthy existence and can indeed accelerate the mutational changes by which a species evolves. The probable consequence, though, is for evolution to be retrogressive, rather than advantageous. The second problem is much more tangible. The use of chemical compounds can quickly lead to the destruction of the soil crumb structure. Soil particles become finer and can be washed or blown away as dust in rainy or windy weather. The topsoil, in which most of the nutrients are stored, is then lost, making the ground less fertile. This increases the need for artificial fertilisers, which then compound the erosion problem. Finally, the chemicals applied in this act of compensation can blow about during application, to be inhaled by any local population, causing health problems that may, in the worst-case scenario, be fatal. Crops not destined for treatment can also be contaminated (and hence damaged or even destroyed), though geotextiles now available can help to prevent this problem and can also restrict to a considerable extent the occurrence of soil erosion.

2.4.2 Side effects Harmful human activities do not consist exclusively of discarding chemically modified consumer goods. In our wish to survive, acquire, explore, conquer and so forth, we produce a wide variety of other side effects, too numerous to describe in detail. Suffice it to say that the end results of our actions in producing or using energy, medical products and agricultural crops, or in excessive hunting, overfishing and destruction of forest cover, tend to be entirely negative from the viewpoint of global health. While we continue to replace land by buildings, roads or other of the appendages of our ‘civilised’ way of life, we can expect to bring about a loss of free space and hence a loss of habitat for animals and a loss of species diversity. If we add to this noise or visual pollution, then we induce terror, behavioural changes and possibly even physical damage into the equation, not to mention a reduction in aesthetics that can bring about emotional distress. Our electromagnetic onslaught, compounded by excess power use and by the current state of information overload to which we subject ourselves may, according to

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Environmental impact of textiles

some experts, cause other physical changes, such as damage to the brain, that will not improve our existence. Add to these problems the effects of compounds released to the atmosphere. Gases that are poisonous to humans or that remove oxygen can bring about drastic harm to individuals, either directly or by increasing climate change effects, such as global warming, tornadoes, floods, and so on. Liquids or gases discarded may also be toxic (* A-2, W-3) to animals, plants and fish, as well as to human beings. Oily liquids can change flotation properties of birds or can be carcinogenic. Detergents may alter the balance of aquatic species. Toxic solids at microscopic size (* L-2) can impede breathing or stunt plant growth. Thus, water damage, biodestruction and other effects can be devastating to the Earth’s health. Here again, textiles are invaluable aids in many of the filtration systems used to minimise the spread of pollution. Finally, there are the other actions of human beings that must be tolerated by the ecosytem. Outbreaks of fire, accidents, explosions of bombs and dust production from such events as erosion or blasting operations are all likely to have some adverse effect on planetary health and hence on our survival. Clearly, there is much more damage caused to the Earth’s health than that from the actions of the textile industry, even though the industry has some part in many of the causes of harm described above. In particular, it should be noted that textiles intended to provide protection against environmental problems may bring about such problems during the course of their manufacture. However, no quantitative or even qualitative survey has yet been carried out of what blame can be squarely attributed to the textile industry, in contrast to the blame allocated to the industry solely as an auxiliary operation connected to some other cause of harm. It is time to take a closer look at what real problems the industry can legitimately be accused of causing.

3 The nature of textiles

3.1

Properties

Before trying to get any idea of how textile production can affect the environment, there are some basic facts that have to be recognised. These stem mainly from the nature of textile materials themselves and bring about the need for special consideration that is not always realised by people even closely involved in the industry. The first fact that needs to be accepted is that textiles are unusual. This may seem strange at first, considering the number of pieces of cloth, strands of yarn or fibre bundles lying around in every corner of the planet, but, despite their ubiquitous nature, textiles are an extremely odd type of substance. To be useful, they have to combine a wide range of properties, such as adequate strength, high flexibility, the ability to accept many different chemical treatments, optical, thermal or electrical characteristics of a variable nature as desired by the user and ease of maintenance. It is difficult to imagine any other engineering material that could achieve half of these necessary attributes.

3.2

Textiles as engineering materials

It is important to appreciate that textiles are indeed engineering materials in the true sense of the term. A textile product is manufactured by carrying out a range of treatments, which may be any combination of mechanical, chemical or physical in nature, just as happens with any other engineering material. The difference in textiles lies in the basic starting unit, the fibre. Fibres, though, are not typical engineering components. If you compare a fibre with a metal rod, a wooden beam, a slab of concrete, a brick or any other solid material used in engineering applications, there is an obvious difference. If any of the other solids are pushed, they move away in the direction of the push. A push on a fibre, yarn or fabric, though, does not move it away in a simple straight line. It makes it distort and fold up on itself. This is the basic cause of the difficulties that have existed in the manufacture of textile materials throughout history. 17

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Environmental impact of textiles

The problem is two-fold. First, because the fibres, yarns and fabrics have such low rigidity, it is not possible to put them into a specific position and expect them to stay there. As soon as they are left unsupported, they will collapse under the influence of gravity, even if there are no more forces acting on them, and lose the shape they had before they were released. Second, the basic unit is so small that it is impossible to work with individual components of textiles. It is necessary to operate, literally, on thousands or even millions of fibres at a time. Each of them will behave in a slightly different way from what might be expected when considering the forces acting on it. This creates problems of a special kind. The solutions that have been adopted over thousands of years of textile production all have in common the fact that operations are carried out on the fibres in large quantities in a manner that attempts to control most of them, while accepting the inevitable need to recognise that some will behave in an undesirable way.

3.3

Principles of textile manufacture

For the reason noted above, the machinery needed to produce textiles cannot be simple. Few portable pieces of textile production equipment exist today, with the exception of hand production equipment such as knitting needles, embroidery frames, looms and drop spinning equipment still used by craft workers or indigenous people. As a direct consequence of this, in the vast majority of cases textile production equipment is massive, complex, expensive and difficult to use effectively in its aim of manipulating millions of tiny particles of flexible units at a speed high enough to satisfy the demand for its products. From the ecological perspective, this has two major consequences. First, textile production uses vast amounts of energy. The high demand and the large size of machinery forces the use of a lot of power in all parts of the world to keep the flow of materials going. Second, because of its complexity, the actual production of the machinery is environmentally very costly. The steel for stable framing, supports, protective covers, shafts, bearings and so on, has to be mined and refined. So too do the various non-ferrous metals used in reducing weight, improving electrical or corrosion resistance properties or providing more durable gears in the equipment. Plastic products used to enhance electrical, thermal or acoustic insulation have to be derived from oil, once it has been extracted from great depths below the surface of the ground or sea, by complex chemical reactions. All of these processes use energy, consume raw materials and produce waste matter as pollution discarded to the air, water or land once the intermediate product of the particular stage has been made.

3.4

Energy

As a result of this high environmental cost (and, even more of a spur, the cost of wasted energy), there have been many attempts to produce energy in less costly ways. The use of coal, oil, gas and electricity has been tried, in turn, over the 200

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years or so that have elapsed since the Industrial Revolution first introduced the use of power in textile production.

3.4.1 Coal Coal, the fuel that drove the Industrial Revolution, is rapidly disappearing from use for electricity generation in the developed nations. It creates too many problems, from those encountered during its extraction to those produced by its combustion. Miners working in risky underground locations are constantly in danger of mine collapse, fire, poisonous gases or lung problems and it is not unusual to read of major disasters in those places where coal faces are still worked. The residual piles of waste make a hideous mess of unsightly scars on the face of the Earth. Burning coal gives rise to smog or other atmospheric pollutants (* V-3, A-2, A-3) (see Table 1.1 for explanation of codes) and to health problems induced by breathing the toxic by-products resulting from the combustion of impurities in the coal. However, there are still coal-powered energy generation plants in operation in many parts of the world, to the detriment of our environment and the health of people living on the planet.

3.4.2 Oil The combustion of oil is currently a popular form of energy production. Oil itself is cleaner-burning than coal, but can cause major problems for the environment in its production. The oil wells that proliferate in those parts of the world where ‘black gold’ is extracted fill the air with fumes (* A-2) from the burning oil that appears at the top of each well. The scars on the land left after sinking a well are as ugly (* V-1) as those left by coal mining, and the pipes must often be sunk to a greater depth than these mines in order to reach the oil site. Drilling operations also produce ecological disturbances, from the displacement of wildlife and the arrival of unsightly equipment to the burning of the fuel used to power the rigs. When the oil is moved, too, the spills (* W-3) that are so common in our modern world can each kill or maim literally thousands of living creatures.

3.4.3 Gas For reasons of cleanliness and economy, many textile factories have adopted gas as the source of at least a part of their energy. Coal gas, the original fuel in this category, merely transferred the pollution from the point of use to the point of production, since it was manufactured by burning coal. It was also notorious for its toxic (* A-2) nature. More recently, coal gas has been replaced by natural gas, extracted from the ground along with oil, which is cleaner burning and not toxic. Unfortunately, gas of any kind cannot be carried around easily, so pipe lines or pressurised containers are needed to be able to make use of this fuel. It also has to

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Environmental impact of textiles

be refined to some extent to keep it clean and has an odour that can be objectionable to some people. More to the point, even if it is completely pure, it still produces considerable amounts of carbon dioxide when it burns, adding a significant contribution to the global warming problem.

3.4.4 Electricity All of this brings us to consider the most common source of energy in textile plants, electricity. At first glance, it is the ideal fuel. It is clean, convenient, versatile and has all those other attributes that we seek to make our lives easier. Examine the situation more closely, though, and a different perspective begins to emerge. All those benefits, it is true, are experienced by the user, but the way in which electricity is actually produced is far from ideal. It may be the result of burning coal or oil, with the drawbacks already mentioned. It can also be generated by burning all kinds of waste material, much of which is domestic pollution, with the consequent release into the atmosphere of carbon dioxide (* A-1) and even more undesirable substances created as by-products of the chemical combustion process (* A-2). In an attempt to give electricity generation a better image, modern production has relied heavily on hydroelectric generation techniques. These involve allowing a large quantity of water to flow from a higher to a lower level through a pipe in which turbines are caused to rotate by the rushing motion of the water. Apart from the need to produce the equipment, potentially an environmentally costly process in itself, there is often a need to create artificial height differentials so that the water has somewhere to flow from and to. This can mean diverting rivers or streams, building dams, flooding valleys and excavating tracts of land, ecologically expensive ways of providing a flow of water.

3.4.5 Nuclear power The proliferation of nuclear power plants over many parts of the world is an indication of how much promise this technique was once believed to have as an alternative means of producing energy. The unfortunate truth, of course, is that there are drawbacks to nuclear energy that were either not foreseen or were mistakenly assumed to be trivial. The first of these to surface was the difficulty in disposing of spent fuel. Nuclear fuel rods contain highly concentrated radioactive elements. Their activity cannot just be turned off once the fuel is spent. At the end of its useful life in terms of an energy source, there is still a dangerously high level of radiation left in the atoms of the radioactive element. This is not enough to make it possible to take advantage by generating electricity, but certainly enough to kill off a few thousand people by radiation sickness if it were to be left lying about (* L-2). The solutions adopted to overcome this drawback include reprocessing and storage, but these, especially the latter, remain problematic in view of the costs

The nature of textiles

21

involved and the risk of leakage over the enormous storage time needed. Even if the material is encased in concrete or stainless steel containers and buried in deep water, cracking or corrosion can occur, so that the nuclear waste (* W-3) can spill out into the sea. From there, fish and other aquatic life can become contaminated, or air currents, water flow and earth tremors can distribute the harmful material around the surface of the planet. Sadly, the radioactivity is likely to last for a much longer time than the encasing materials, so the results of our careless discarding of radiation are being bequeathed for future generations to inherit. A second side-effect has been brought to our attention in a dramatic way. Sellafield, Pickering and Chernobyl are names that conjure up images of nuclear power plants that went wrong. The latter, especially, taught us that one careless act at a nuclear plant can bring about a disaster capable of destroying the livelihood, and lives in many cases, of thousands or millions of people. The margin of error between nuclear fuel that reacts fast enough to create energy at a reasonable pace, and that reacting fast enough to blow its container apart, spreading devastation over the face of the earth, is not all that great. Even when the fuel cells are controlled properly, there are still undesirable consequences of the process. Electricity generation takes place because the nuclear energy heats water to steam, which is then used to drive turbines. The spent water is hot and has to be discarded somewhere, often into the nearest river or lake water. Although it has cooled down sufficiently to avoid boiling any nearby fish in the water, it is still warm enough to make the area uninhabitable for them (* W-1). Other species, both fish and plant, can take over and change the balance of nature in the region downstream of the plant discharge site. The consequences for the environment and for the people living in the area are not yet understood, but the changes already occurring as a result of this nuclear warming give us cause to reflect that our energy comes at a tremendous cost to our planet’s natural health.

3.4.6 New energy sources One consequence arising from our realisation of the risks of nuclear mishap is the effort to find new ways to provide energy. Solar, tidal and wind energy have all been proposed as ways in which electrical energy can be produced. The hydrogen cell has been suggested as a means of powering devices in place of intermediate electricity generation. At first sight, again, all these methods of providing supposedly unlimited energy seem impressive. They are natural, reliable (with certain fairly obvious limitations, such as location or time of day) and, more importantly, free. There will almost certainly be unexpected drawbacks, as the lessons of history have shown. Before we find them, however, there are obvious ones that can be predicted even without experiencing them, all resulting from the nature of energy supply. Energy production is complicated. The natural source has to be collected, harnessed, converted into electricity and distributed to its point of consumption. In

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Environmental impact of textiles

all of these steps, equipment is essential. This equipment, like that used to make textiles, is generally large, heavy, complex and made of many different materials, making it environmentally costly to produce. Its manufacture and operation produce pollution, because waste material is generated in the former case and lubricants are needed in the latter, contaminating the air, water or land. It also has a relatively short life, because materials subjected to heat and mechanical action from sun, weathering, water or wind will eventually corrode or suffer fatigue fracture. As a safety precaution if for no other reason, they will have to be replaced by new equipment roughly every 20 to 30 years, thus producing a continual environmental cost that never ends. More importantly, perhaps, is the mental attitude that will be engendered by the use of these ‘revolutionary’ energy sources. If energy is cheap (free?) and appears to be clean, then we should be able to use it in unrestricted amounts. We can waste it without any qualms of conscience and need not concern ourselves with the consequences of our actions, because neither the environment nor our pockets are being harmed in the process. It is only when we look at the entire cycle, from starting to make the power generation equipment to the end results of using it, that we can begin to realise how wrong our assumptions might be. The actual energy consumed in making or using a product is a minor fraction of its overall environmental impact, because the extraction of materials to manufacture the equipment designed to make the energy or to use it, and the pollution resulting from such extraction, must also be taken into account. Unlimited energy use means unlimited equipment production and hence unlimited ecological degradation. So the textile industry, like most others, is unlikely to find any sop to its collective conscience with respect to power consumption in the foreseeable future. Unfortunately, this is not the only way in which the environment suffers for the sake of the industry. Every stage of manufacture, from fibre production or harvesting to shipping, inevitably involves damage (considerable in some cases) to the environment. The following chapters will summarise how this damage arises, looking briefly at its consequences and examining the ways in which it can be alleviated. In addition, the way in which textiles can themselves be harmed by the environment in the process of degradation will be considered.

4 Textile fibre production

4.1

Scope of the industry

When the actual ways in which textile goods are made are put under close scrutiny, plenty of instances of environmental concern can be found. These will be looked at in sequence, following the various stages in turn, from growing or manufacturing the starting materials, the fibres, to the point at which an end product is shipped to the final consumer in readiness for use. First, though, the potential magnitude of any problem is examined briefly by estimating the size of the industry. An anonymous author1 records annual world production of textile fibres at about 60 million tonnes, of which over 50% is synthetics. This is in agreement with another writer,2 who quotes a value for world production of textile fibres of almost 58 million tonnes, with chemical fibres amounting to 31 million tonnes. Any growth likely to take place will probably be in the latter type of textiles; Schenek3 surveys comprehensively the state of natural fibre production and notes that, although the cotton harvest grew by almost 50% in the last few decades of the 20th century, the production of other natural fibres is likely to remain more or less steady. His estimate of total natural fibre production is in slight disagreement with the figures quoted above, since he records it at only about 26% of world total. Vishwanath4 presents an outline of the history of silk production, with figures giving details of the share from each country, quoting current production at 81 000 tonnes, worth $6.5 billion, and examining the factors that could determine whether or not production will increase from its present level.

4.2

Natural fibre production

Having gained some idea of the extent of production figures, the fibre-growing industry will be examined. As examples of typical raw materials, cotton (a plant seed-hair fibre), linen and the similar (bast) fibre jute, silk (an extruded animal fibre) and wool (an animal hair fibre) will be considered. Wool and linen almost 23

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Environmental impact of textiles

certainly predated the other two historically, but history does not have to be followed slavishly, so the vegetable fibres, cotton and linen, will be dealt with first, followed by silk and then wool before looking finally at the artificial (man-made) fibres. Other examples of each type of category exist, but their production techniques resemble those described below for the archetypal ones.

4.2.1 Cotton Cotton is grown on a bush, 0.6 to 6 metres high, in a field. Good growth of a high quality fibre requires a minimum of about 150 days of sunlight each year and plenty of fresh water. Cotton can therefore only be grown in a relatively narrow belt of the Earth’s surface, within about 35 degrees latitude of the equator, and in one or two other areas of the planet where local conditions are atypical for the latitude. The quality varies greatly in different locations, with Sea Island and Egyptian cotton generally considered to be the finest and Pakistani, Russian or Indian inferior. In order to achieve the optimum quality, efforts are usually made to enhance growth conditions. Fertilisers, insecticides and herbicides are commonly applied during the growing season. A considerable part of an international conference5 held in 1998 was devoted to this topic. Pertinent subjects discussed include enhancing quality by adjusting growth or soil treatment conditions and control of pests to increase yield. Daniell6 suggests that genetic engineering provides the best possible way of achieving both of these, since natural breeding has reached its limit because of species incompatibility and the small range of properties that can be incorporated into a plant by natural selection. This view is echoed by Wilson,7 who reviews current and future biotechnology, suggesting (among less fanciful ideas) the possibility of developing blue cotton plants to avoid the need to dye cotton for jeans. Although this may appear to be a good idea at first sight, it is appropriate to wonder how environmentally costly the process will be, both in the short term, because of the technology needed, and in the long run when different shades of blue are demanded by fickle consumers or when cross-fertilisation by wind distribution has eliminated all bushes bearing natural white cotton fibres. There is also the concern, a notable one at the moment, regarding contamination by genetically modified plants of other plants, not modified by this technology, in the vicinity. Other contributors at the 1998 Beltwide Conference, such as El-Lissy et al.8 give information about a scheme to eradicate insects, such as boll weevils or budworms, indicating that significant declines took place between 1995 and 1997. However, a conflicting note is sounded by Williams,9 who estimates that insect losses still represent 9.42% of the crop, the equivalent of 2.5 million bales of cotton and almost $1.5 billion dollars in financial losses. Many papers at the same conference deal with combination of biological and chemical controls to achieve sound management of insect pests, including aphids, leaf whitefly or sweet potato

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whitefly. Yet other contributors concentrate on soil tillage and methods of actually adding fertilisers to improve yields. Another important aspect of cotton growth is the need for a plentiful supply of water. Drought conditions can bring about a reduction in the quality of the cotton not only because of the lack of waterborne nutrient flow but also as a consequence of changes in fertiliser effects.10 For this reason, irrigation water must be pumped to the cultivation site if natural water supplies are insufficient for satisfactory growth. The chemical additives used have adverse effects on the land (* L-1, L-2) (see Table 1.1 for explanation of codes), as discussed in Chapter 2, and the need to irrigate the plants also brings about problems, though usually not quite such serious ones. First, unless gravitational flow can be harnessed, water must be pumped mechanically to the site, which involves manufacturing and powering machinery for the purpose. This machinery, like all the mechanical aids mentioned already, is itself environmentally costly. Second, the flow of water can exacerbate erosion and chemical leaching problems. Third, unless applications are carefully coordinated, the flow of water can remove some of the chemicals before they have accomplished their purpose, necessitating the application of more of them to control the growth of pests for which they are needed. Once the plant has produced its crop and the seed hairs are open, harvesting must take place. In these days, despite the fact that hand picking can yield a better quality of product, harvesting is almost invariably done by machine, simply because the cost of labour is too high to make the relatively slight improvement in fibre quality worth the extra cost involved. This machinery adds an environmental load to the process. The timing of picking, too, is less easily controlled when mechanical picking takes place. Manual methods can allow selection of just-ripe bolls to be made, but no machine currently in existence has this capability. Another conference, this time in Bremen,11 included details regarding the means for carrying out standard tests for measuring maturity, along with stickiness, dust or trash levels, fibre length and high volume instrument (HVI) testing. One method suggested12 for estimating the time at which cotton reaches its optimum maturity uses image analysis of fibre bundle tests. The next stage in cotton fibre production is the ginning operation, frequently taking place in the field in the immediate vicinity of the crop and designed to separate the cotton fibres from the seed fragments. Vizia and Anep13 claim that ginning is the weak link in cotton processing in India, because it suffers from poor efficiency and problems with cleaning and storage. They outline proposals for improvement in the future. Lugachev,14 in an effort to improve quality, has devised a new energy-saving technique for doffing fibres in sawtooth ginning by making use of a reflected air flow. Anthony and Byler15 are more optimistic on behalf of American producers; they suggest that careful control of the ginning process (especially in the matter of moisture uptake and machine type), together with a mechanism that includes computer measurement, improves fibre quality, gives higher yield and produces fewer short fibres and neps. The scheme they recommend

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is one in which moisture content, colour and foreign matter are measured by standard methods, after which this information is fed forward or back, so that ginning can be increased if necessary or omitted completely if it is not needed, thus providing better separation of seed-coat fragments with minimum fibre damage. These fragments are often regarded as useless but, in a notable example of environmental responsibility, Bader et al.16 use them for cattle feed and as replacement for pine chips in poultry barns.

4.2.2 Leaf and stem fibres Perfectly satisfactory textile fibres can also be obtained from other parts of plants than the seed hairs, notably the stem and the leaf. Stem, or bast, fibres tend to be less ecologically harmful than seed-hair ones. Linen, a typical example, can grow with virtually no attention or fertilisers, as long as water is available. Tarres17 discusses the cultivation of flax in the past and predicts how it might change in the future, also describing pretreatments and textile uses. Mackie18 carries out a similar task with regard to hemp, another stem fibre. For best quality fibres from both sources, a relatively small amount of care needs to be taken. The climate must be very moist but mild. The selection of optimum quality fibres has traditionally been done by hand in many countries. This makes the process more costly financially, but is environmentally beneficial. In recent times, though, mechanical methods of harvesting have been introduced, with adverse effects on the environment and a reduction in the quality of the fibre produced. Once harvested, the flax must be treated to release the usable fibres from the surrounding woody stalk and interior pith. The most important part of this process is the retting, or soaking, that allows slow decomposition of the woody parts to take place. Schulze19 notes the impact of flax fibre properties on spinnability. He investigates the performance of flax blended in turn with cotton, viscose, polyester and aramid components, finding that the importance of retting is paramount for successful yarn production. Traditionally, retting was done in pools or ditches, which tend to give a better quality of product, because the advantageous moist conditions are preserved longer in their shelter. If the flax plant is cut by hand and left to ret in the ditch, then the environmental load on the planet is minimal. Jute has similar advantages; Chattopadhyay20 outlines the retting process and describes the physical characteristics of the fibre, mentioning its chemical composition, sensitivity to alkalis and the need to take precautions to avoid yellowing if bleaching is attempted. Sadly, modern technology cannot accept such a beneficial solution. Dew retting or tank retting is more frequently used today, using mechanical devices to turn the stalks, maintain high temperatures and remove seeds. Lennox-Kerr21 reports the development of a new mechanical treatment process for flax to produce linen fibres that resemble cotton in their properties and structure and can be processed on equipment designed for cotton.

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4.1 Effect of pH on flax retting (source: see ref. 22).

Mechanical harvesting speeds up the cutting process and chemical agents reduce the retting time from two or three weeks to a few days or even less. Henriksson et al.,22 for instance, propose an oxalic acid-based system for chemical retting of flax that compares favourably with the more common enzymatic retting. Figures 4.1 to 4.4 (showing the effects of pH, oxalic acid concentration, sodium dodecyl sulphate concentration, time and temperature on retting) indicate that higher pH conditions bring about better retting, which is highly temperature dependent. The authors find that retting is virtually complete if treatment is continued at 75oC for as short a time period as a mere two hours. The presence of a detergent is needed to obtain satisfactory retting. Tests of tex, tenacity and elongation properties again indicate that the fibre can be processed on cotton production equipment. Although there are continuing arguments about whether the fibre quality is enhanced or reduced by the change from manual to mechanical or chemical processing, it is the economic aspect that really plays the most important part in the debate. The end result is, once again, a damaged planet.

4.2.3 Silk Silk production brings about a different set of considerations. The process involves rearing the silkworm grubs to the chrysalis stage, then unwinding the silk filaments from which the case enclosing this chrysalis is formed. Most commercially

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4.2 Effect of oxalate concentration on flax retting (source: see ref. 22).

4.3 Effect of sodium dodecylsulphate concentration on flax retting (source: see ref. 22).

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4.4 Effect of temperature and incubation time on flax retting (source: see ref. 22).

produced silk is of the cultivated variety, depending on feeding the worms a carefully controlled diet of mulberry leaves grown under special conditions. This need gives rise to the environmental costs of establishing controlled atmospheres and employing rigid growth conditions. Wild (‘tussah’) silk production, conversely, involves minimal interference with nature, so there is a great deal of interest in developing the fibre commercially. Akai23 surveys the available techniques, focusing on the main points of manufacture and on predicting the importance of commercial manufacture of wild silk in the 21st century. Jahagirdar24 feels that marketing is the main constraint, in view of the lower quality (compared with cultivated silk), but stresses that the fibre can provide a major source of income for millions of tribal people in India. Krishna Rao et al.25 agree, noting that the income is year round rather than seasonal, and point out that the forest cover is an easy source of food and plants, so constituting a base for commercial development. Ghosh26 describes improved techniques for enhanced quality and productivity and mentions the slow transition to better working conditions and higher incomes for workers, describing advances in powered machinery for reeling and spinning. In the context of this book, an important point is made by Nadigar,27 who notes that wild silk is exceptionally ecofriendly, since it uses no hazardous chemicals and encourages the socially beneficial activity of preserving the forests. He sounds a note of caution in that the dyeing and printing chemicals currently used are toxic substances (* W-3), but maintains that ecofriendly dyestuffs can readily be substituted for them. Shetty and Samson28 describe the production of silk without the need for traditional mulberry leaves, an obscure craft of tribal and hill

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peoples up to the time of writing, but suggest it as a potentially important commercial crop. Problems shared by all types of silk are brought to light in the literature. The first of these is the need to control reeling in automatic processing, a need that Hu and Suzhou29 discuss in some detail. Second is the importance of understanding the effects of cocoon shape or quality on filament uniformity, a topic reviewed by Singh et al.30 Maribashetty and two colleagues31 analyse why silkworms fail to produce satisfactory cocoons, dividing them into pathological, physiological, environmental and genetic reasons. They discuss abnormal development in the silk gland, spinneret and nerve malfunctions, and hormonal or disease causes, noting that control of both temperature and relative humidity is critical during the larval period. Cultivated silk, in addition, needs other special conditions. Selected mulberry trees are grown to act as homes for the silkworms and their leaves are hand picked daily. The trees, like cotton plants, require fertiliser and pesticide applications, though they tend to have lesser demands than cotton plants. They also have to be selected carefully, as the silk quality is highly dependent on the diet fed to the worms. One major problem that has emerged is the need to protect them from poisoning; Patil32 outlines the sources of contamination of mulberry leaves, describing the symptoms of poisoning (* A-2, L-2) by agricultural fertilisers, tobacco, factory exhaust gases and biopesticides, with a list of precautions to be taken in order to minimise the effects of these modern toxins. Thus, the carefully controlled conditions needed for silkworms to work their ‘miracles’ are environmentally expensive to maintain. Establishing the perfect atmosphere for the grubs needs a supply of clean air, apparatus to heat or cool to the correct conditions and power to operate the entire system. Extraction of the fibres by steaming to kill the silk chrysalis requires steam. The unwinding step depends on sensitive machines that are designed not to break the fragile threads. The cleaning process, necessary to prevent the newly wound threads from sticking to each other, uses hot water (often with detergents) to remove the silk from the gum, and the waste liquor is usually discarded to the ground water, acting as a pollutant (* W-3) once more. All of these components of the production process are environmentally costly. Silk, however, is not the only animal fibre grown directly or indirectly from insects; spiders can also produce a similar filament, though their ability has not yet been adopted with any commercial success because of the difficulty of unwinding the thread without breakage. However, there is one piece of work in this general area that deserves to be mentioned as it may represent the type of future development that can be expected in the industry. Smith33 notes that genetic engineering has enabled a Canadian company to insert a gene from a spider into the DNA of a goat so that the goat’s milk contains a spider silk protein that can be extracted and made into a filament with extremely high strength. Projected uses include medical sutures, vascular grafts, military and law enforcement protective clothing, structural engineering and packaging.

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4.2.4 Wool Wool is a natural animal fibre of a different kind, made from the inner fine hair of the sheep or goat. Again it is responsible for a new set of constraints. It is often advertised as the ‘perfect’ fibre, as a result of its desirable properties and is indeed at first glance worthy of that compliment. As we shall see later, though, its perfection is considerably reduced when its overall ecological impact is taken into account. Its production nowadays is complicated by a multitude of chemical treatments that add considerably to the environmental cost of achieving a fibre that is satisfactory to fussy modern consumers. The sheep is, admittedly, a beneficial asset to the planet. Not only does it provide us with the warm fabrics that have kept out cold climates since time immemorial, but it is also a source of meat. Unfortunately, the animals that provide the best wool tend to produce poor quality meat, and vice-versa. Sheep can thrive on marginal land where virtually nothing else will grow; the moorlands of northern England where these hardy beasts make their home have only to be seen in order to appreciate just how useful they actually are in converting scrub grass into vital end products. They also provide manure to fertilise the ground on which they graze or for sale to avid gardeners. Harvesting the wool consists of shearing the animal on a yearly or twice-yearly (depending on climate) basis. Hand shearing has virtually disappeared today, to be replaced by the use of electric shears. These do not consume a great deal of power, so are not too costly in environmental terms. But perhaps the most significant aspect of sheep growth, from the point of view of this book, is the use of sheep dip, an antiseptic agent, to prevent infection or to remove insects and other pests from the animal’s coat, which (depending on the exact formulation used) may seriously contaminate (* W-3) water supplies.

4.3

Artificial fibre production

The discussion so far of types of production has given a brief overview of most of the natural fibre concerns. However, natural fibres currently represent less than half of world textile production and we must turn our attention to the other major source, artificial fibres. These can be classified into three types, true synthetic polymers, regenerated materials and modified natural ones. Production figures for synthetic fibres during the year 2000 were quoted at 31.3 million tonnes,34 a figure that has been more or less constant in recent years; this should be compared with the world total of about 45 million tonnes if natural fibres are also included35 to give some indication of the disproportionate amounts of the two types in use nowadays. In the first two classes of artificial fibre types, the true synthetics and the regenerated ones, there are three main production techniques, dry (or solvent) spinning, melt spinning and wet spinning, details of each of them being found in

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standard books of textile technology. All of these have an impact on the planet that can be appreciated readily by an examination of what happens in each case. Before we look at these processes, though, we should consider the way in which a polymer is created.

4.3.1 Polymer preparation The usual, almost exclusive, source of raw material for polymer preparation is oil. As mentioned in Chapter 3, the extraction of this raw material is environmentally very costly and the production of polymers from it is not much less so. The oil is first ‘cracked’ (separated into various segments of a limited small range of molecular weights), usually with the aid of specific gravity or boiling point as indicator. The appropriate segment for making polymers is then converted into a form able to produce the starting material for the polymerisation step. This involves a chemical reaction between two precursors, often with heat, to produce a white solid that is then chopped up into chips for convenience in handling. The entire operation, as can readily be envisaged, uses large amounts of energy, produces waste in the form of gas, liquid or solid by-products (* A-2, W-3, L-2), and may often be quite a messy activity for the people engaged in it. Thus, the actual acquisition of the precursor for polymer manufacture is environmentally costly before any further processing is carried out. The chips that emerge are relatively clean and easy to handle, however, and can readily be passed on to the next stage, the actual fibre production step.

4.3.2 Dry spinning In dry spinning, a solution of the polymer in a suitable solvent is extruded, or forced, through a spinneret, a disc containing many fine holes through which the jet of polymeric liquid passes. The result is a set of multiple strands of filament, which are then drawn to strengthen them by means of a godet, a device exerting a force of traction on them. As the solution emerges from the spinneret and falls away from the solidification zone under the influence of gravity and the tension exerted by the godet, a stream of heated air is allowed to flow upwards around the newly formed filaments. This warm air increases the rate of evaporation of the solvent, ensuring that the filaments are stable enough to be drawn without breaking. The evaporated solvent is drawn upwards by the air stream, for collection and recycling. A paper36 describing the production of acetate from wood indicates that better absorbency and a closer approximation to the properties of silk can be achieved in this way; the paper describes in detail many aspects of the machinery needed and summarises the properties that are inherent in the fibres. Apart from the usual concerns regarding energy and complex equipment, there is an obvious pollution problem inherent in this method of production. No matter how carefully the operator may adjust the rate of air flow, it will be almost

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impossible to contain all the evaporated solvent within the system. In order to allow the filaments to pass down to the godet, there must be an exit aperture. If it is big enough to allow a solid filament to pass, then it will not prevent a gas from escaping. Even if the rate of input of air is very high, diffusion will ensure that not all the solvent vapour is swept along by the air stream. In the limit, the rate of flow of air needed to attempt to control vapour loss would have to be so great that the filaments would be blasted out of existence before they even reached the exit from the enclosed space, thus defeating the entire object of the technique. As solvents consist of harmful vapours from chemical agents such as acetone (* A-2), there is clearly a need for concern regarding the safety of the nearby workers, as well as that of the ambient surroundings in general.

4.3.3 Wet spinning In wet spinning, used most often in conjunction with regenerated fibres, a chemical reaction is carried out on the starting material to create a solution viscous enough to allow it to be extruded without disintegrating on leaving the spinneret. Immediately after extrusion, a second chemical reaction is carried out on the emerging liquid to convert it into a solid that can be drawn, as before, to form the polymeric filament. In this system, the presence of the chemicals, which may include acids, alkalis, reducing or oxidising agents and bleaches, may well pose a threat (* W-3) to environmental safety. In addition, the initial chemical reaction is likely to be a source of toxic or otherwise harmful agents (* A-2). All these chemical compounds need to be manufactured, again at ecological cost in terms of equipment, energy, raw material extraction and the various other cumulative factors encountered earlier.

4.3.4 Melt spinning Melt spinning, the final spinning method to be considered here, uses heat to melt the polymer, extrudes the resulting liquid through a spinneret, then immediately cools it to a solid form by means of a stream of cold air. Because the melting point of most polymers is not too far below the decomposition temperature, great care must be taken to avoid overheating the material. As these polymers are almost invariably poor thermal conductors, it is a difficult task to arrange for uniform melting to take place at a reasonable rate, without finding a mixture of still-solid chunks and blackened waste product in the apparatus. The risk is compounded if the rate of extrusion is not exactly right, since the polymer will then spend too long or short a time in the heating chamber, and may well clog the spinneret if production is halted to adjust anything. A further difficulty that may subsequently be encountered, applicable to all three of these production methods, is the need to dispose of a large quantity of waste if a careless operator makes a mistake and ends up with a mound of nasty stuff that cannot be used for anything.

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4.4

Alternative fibre sources

One development is the idea of using alternative sources for the starting point of manufacture instead of oil. An anonymous author37 describes the production of polylactic acid, a fibre that has the advantage (unlike virtually all other synthetic ones) of being biodegradable. This matter of biodegradability is extremely important, as will be discussed shortly, and the capacity to exhibit such a property has inspired other fibre research workers. Another anonymous writer38 suggests using a blend of natural cellulosic and thermoplastic polymers to yield a new fibre that can be blended with cotton, while a second paper39 in the same vein claims that a biodegradable polyester can be produced as a block copolymer with other units to give a material that can be used for most practical purposes. In both cases, though, the examples listed do not seem to belong to the type of compound that disappears into the Earth without trace. The usual problems with synthetic fibres that are supposedly biodegradable is that, when they break into tiny pieces, toxins resulting from their breakdown remain in the soil contaminating the surrounding land and hence water (* L-2). Better ‘biodegradability’ usually implies a faster rate of disintegration, but the increased surface area thus produced increases the rate of release of toxins and so makes the presence of these materials even more undesirable. The act of trying to recycle polyester, to be mentioned later, is suggested as an environmental cure, with a note that the efforts to carry out this type of operation for producing fibres are increasing rapidly.

4.5

Inorganic fibres

Another type of fibre that is becoming more important is in the inorganic category. Fibres of this type are produced from materials that are present in the Earth’s crust (or can easily be made from naturally occurring materials there) and that are inorganic rather than polymeric. Examples currently being used or considered as sources of fibre include glass, metals, carbon, asbestos and ceramics.

4.5.1 Glass fibres Glass, existing in a wide range of types for various end uses, is usually made by melting silica (the material of which sand is constituted) at very high temperatures and adding to the melt the necessary materials (oxides of various metals, etc., that impart the desired characteristics to the glass) before extruding the molten glass through a spinneret. Uses of the material are summarised by an anonymous author40 together with a description of the special machinery needs and mechanical properties. High temperatures always incur large energy costs. The extraction of the metal oxides from the ores in which they are present in the ground (plus their purification) is a matter for concern regarding the use of energy, the need for heavy extraction or refining equipment and the production of large quantities of pollution

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(* L-2). The process itself is obviously environmentally expensive and the slag heaps remaining after the metal oxides have been extracted can leave scars (* V-1) on the surface of the Earth that may take years to be assimilated back to provide any semblance of a harmonious landscape. The same factors also have to be taken into account in the production of metal fibres, since ores are essential as their starting materials. In addition, problems can be more serious, because their purification is usually more difficult than that of the oxide. Metals, too, need high temperature manipulation by complex heavy machinery that is environmentally difficult both to make and to operate.

4.5.2 Basalt fibres Basalt fibres made from rock solidified from volcanic lava are suggested by one author41 as an alternative to glass. Until recently, they were used solely in the form of basalt ‘wool’ for thermal insulation purposes, but the article describes new technology for making them into filaments. In comparison with glass, they are more stable to strong alkali, but less resistant to strong acids and can be used in the temperature range of – 200 to + 800oC. The filaments produced are apparently even enough to be used in normal textile structures. One suggested application is as sewing threads for fabrics exposed to high temperatures or adverse chemical environments. Thus, the ecological expense of producing these fibres, stemming mainly from the high temperatures needed in their production, is partly offset by their ability to resist heat, imparting a more extended existence in thermally degrading situations.

4.5.3 Carbon fibres The use of carbon fibres has only become widespread over the past couple of decades or so, but their growth has been rapid since their inception. Gurudett42 traces the development of a type of recently produced, activated carbon fibres, summarising their advantages over earlier ones and lists applications that depend in many instances on an improved adsorptive ability. Again, the complex series of processes and the inert atmospheres needed for carbon fibre production tend to make them expensive from the environmental standpoint.

4.5.4 Ceramic fibres Ceramics are the latest in a series of new materials earmarked for use as fibres. Many of them are oxides, with the same properties and drawbacks as mentioned above, but they usually have a very high melting temperature, which increases the difficulty of manufacture and hence the ecological impact. Others are chemically more complex, requiring difficult techniques of manufacture that are again unlikely

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to improve the Earth’s chances of recovery from their impact if production becomes as commonplace as is generally predicted by their proponents. A typical modern ceramic is silicon carbide, produced in one case43 by melt spinning of chlorine-containing polysilanes under an argon atmosphere, followed by crosslinking with ammonia as a curing agent, then subjecting this precursor to pyrolysis. This produces an Si–N–C system, with properties which the authors compare with those of the simpler Si–C fibre system. A second method of production44 involves infiltrating liquid silicon into carbonised wood at 800 to 1800oC. At 1600oC, rapid liquid infiltration occurs and the resulting ceramic fibre takes on the pore structure of the original wood, so that different properties are obtained when different types of wood are used as starting materials. From the descriptions of these two processes, it is clear that silicon carbide is an environmentally expensive fibre to produce. Apart from the high temperatures required, the need to produce polysilanes or silicon demands complex chemical reactions that place a huge demand on the planet’s capacity to recover from environmental stress, as also does the establishment of an inert gas atmosphere. Indeed, all these new fibres are ecologically very damaging in comparison with the more traditional ones. Their production is deemed to be necessary because of their highly unusual properties, such as heat resistance or their inert nature, which find invaluable applications in satisfying the demands of the space industry or the military that could not be met in any other way. Once again, it seems that the environment is being sacrificed to meet a need that would not be regarded in many quarters as strictly essential.

4.5.5 Asbestos fibres The fourth example of modified natural fibres, asbestos, has a special place in the environmental debate. Long regarded as a wonder material for its good thermal and electrical insulation abilities, it has been recognised as a dangerous substance because of its tendency to cause lung cancer (* L-3). It differs from the other materials in this group in that it does not need any heat or chemical reactions to produce it, merely a sequence of crushing and cleaning operations after it is dug out from the ground. At first sight, then, it would appear to be a desirable product, apart from its carcinogenic nature. Nevertheless, the equipment needed for these purposes is heavy, so that its use, even without its inherent danger, should not be regarded as wholly desirable. In 1999,45 acrylic sulphide was touted as a replacement for asbestos, because it is tough, resistant to alkalis, non-flammable and has high tenacity. It can thus be used as a filter medium for hot gases, as a reinforcing medium for concrete and in other applications where asbestos has been considered to be the only suitable material, as in firefighters’ uniforms, foundry clothing and similar protective garments.

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37

Microbiologically stable fibres

One direction in which research is making progress is in the attempt to produce fibres that are resistant to microbiological agents, thus prolonging their life and benefiting the planet. Jou and Liaw46 set down the conditions for a successful fibre of this type, pointing out that it should be non-toxic, non-allergenic, durable and non-carcinogenic and, if the antibacterial action is effective, it should reduce odour to make a safe, comfortable and healthy garment. Takeda47 claims to have developed such a fibre, with the incorporation of a tetravalent metal phosphate (such as titanium or zirconium), a divalent hydroxide (usually of copper or zinc) and a photo-semiconductor like titanium dioxide. Service48,49 describes Amicor, another new material based on an acrylic fibre, with the same type of behaviour, noting that the antimicrobiological agent can resist a wide range of bacteria, fungi and larger pests, such as dust mites, because it is incorporated into the matrix and can migrate from there to the surface to replace any agent lost by abrasion, weathering, and so forth during use. Stevenato and Tedesco50 make use of a new organic substrate with very fine particle size to provide effective antimicrobial activity without affecting fibre properties adversely. Rhovyl51 add an acaricidal (mite- and tick-destroying) agent to their fibre before extrusion to give long-term action in a fabric that not only destroys dust mites but also prevents subsequent reinfestation. Ward52 also suggests the premanufacturing insertion of an agent for mattresses and other bedding products.

4.7

Effects on the planet

Despite these attempts to increase longevity and safety, however, fibre production of any type is likely to be harmful to the planet in the long term. Costs of producing the fibres must include costs of making the chemical agents or precursors that are needed for growing or manufacturing them, costs of the chemical activity necessary for their production and costs of their handling or transportation around or away from the plant where they are made. These auxiliary costs are seldom, if ever, recognised, yet they exert a considerable influence on the planet that cannot be ignored in any comprehensive consideration of its long-term survival prospects. After the fibres are produced, of course, their adverse influence on the planet does not magically cease. There are still ecological costs that have to be paid. The next two chapters will consider what happens when they are made into further textile products in the form of yarns or fabrics.

References 1 2 3 4

Anon., Melliand Textilber., 2001, 7 (Sep), 156. Anon., Melliand Int., 2001, June, 84. Schenek, A., Int. Textile Bull., 2002, May, 8–17. Vishwanath, S., Int. Textile Bull., 2002, May, 20–21.

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5 Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999. 6 Daniell, H., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 595–598. 7 Wilson, A., Int. Dyer, 1998, 83(9), 35–36. 8 El-Lissy, O., Patton, L., Frisbee, R. et al., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 1001–1006. 9 Williams, M.R., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 957–959. 10 Mullins, G.L, Burmester, C.H. and Schwab, G.J., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 615–618. 11 Proceedings Int. Comm. on Cotton Testing Methods, Bremen, March 10–11, 1999, International Textile Manufacturers Federation, Zurich, 1999. 12 Schneider, T. and Rettig, D., ITMF, Proceedings International Conference on Cotton Testing Methods, Bremen, March 10–11, 1999, International Textile Manufacturers Federation, pp. 71–72. 13 Vizia, N.C. and Anep, G.R., Asian Textile J., 1998, 7(7), 68–74. 14 Lugachev, A.E., Tekh. Tekst. Promysh., 1998, 2, 19–21. 15 Anthony, W.S. and Byler, K., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 703–708. 16 Bader, M.J., Bramwell, R.K., Stewart, R.I. and Hill, G.M., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 1698–1699. 17 Tarres, X., Revista Ind. Textil, 1998, 360, 32–48. 18 Mackie, G., Textile Month, 1998, October, 47–51. 19 Schulze, G., Melliand Textilber., 1998, 79(5), 310–312 and E 77–78. 20 Chattopadhyay, D.P., Colourage, 1998, 45(5), 23–26. 21 Lennox-Kerr, P., Textile Month, 1998, October, 52–54. 22 Henriksson, G., Eriksson, K-El., Kimmel, L. and Akin, D.E., Textile Res. J., 1998, 68, 942–947. 23 Akai, H., Indian Silk, 1998, 37(6–7), 18–20. 24 Jahagirdar, D.V., Indian Silk, 1998, 37(6–7), 65–69. 25 Krishna Rao, J.V., Singh, R.N. and Singh, C.M., Indian Silk, 1998, 37(6–7), 79–83. 26 Ghosh, S.S., Indian Silk, 1998, 37(6–7), 51–52. 27 Nadigar, G.S., Indian Silk, 1998, 37(6–7), 71–73. 28 Shetty, K.K. and Samson, M.V., Indian Silk, 1998, 37(6–7), 21–25 plus 53–64. 29 Hu, Z. and Suzhou, J., Int. Silk Textile Tech., 1998, 18(5), 29–35. 30 Singh, R., Kalpana, G.V., Sudhakara Rao, P. and Ahsen, M.M., Indian J. Sericulture, 1998, 37(1), 85–88. 31 Maribashetty, V.G., Chandrakala, M.V. and Ahamed, C.A.A., Indian Silk, 1999, 38(3), 11–13. 32 Patil, C.S., Indian Silk, 1999, 38(3), 7–8. 33 Smith, W.C., Textile World, 2001, 151(2), 34. 34 Anon., Int. Textile Bull., 2002, March, 6–8. 35 Anon., Melliand Int., 1998, 3, 146–148. 36 Anon., Tinctoria, 1998, 95(9), 36–39. 37 Anon., High Perf. Textiles, 1999, March, 4101.

Textile fibre production 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

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Anon., High Perf. Textiles, 1999, March, 2–3. Takasago International, High Perf. Textiles, 1999, February, 2. Anon., Bull., Sulzer and Ruti, 1998, 36, 4–5. Anon., Textiles Mag.,1998, 27(4), 20–21. Gurudett, K., Man-Made Textiles in India, 1998, 41(8), 345–347 and 41(11), 481–485. Kurtenbach, D., Martin, H-P., Muller, E. et al., J. Eur. Ceramic Soc., 1998, 18(13), 1885– 1891. Greil, P., Lifka, T. and Kaindl, A., J. Eur. Ceramic Soc., 1998, 18(14), 1961–1973 and 1975–1983. Anon., High Perf. Textiles, 1999, January, 2. Jou, C.H. and Liaw, H.J., J. China Textile Inst., 1998, 8(4), 371–379. Takeda Chemical Industries Ltd, Med. Textiles, 1998, October, 2. Service, D.F., Chemical Fibres Int., 1998, 48(6), 486–489. Service, D.F., Revista Ind. Textil, 1999, 364, 49–56. Stevenato, R. and Tedesco, R., Chem. Fibres Int., 1998, 48(6), 480–485. Rhovyl, Med. Textiles, 1998, December, 2. Ward, D.T., Int. Textile Bull., 1999, 45(1), 44–45.

5 Yarn production

5.1

Starting material state

5.1.1 Vegetable fibres At the end of the fibre production process there are millions of tiny units, ready to be transformed into a yarn or some other type of fibre assembly in the next stage of the textile manufacturing operation. Their actual state depends very much on the type of fibre involved. In the case of vegetable fibres, the product is a dirty, tangled, contaminated mass that may contain a variety of plant or animal by-products. The former will be governed by the efficiency of selecting only fibres, rather than including other traces of the cotton, linen, and so on, plant in harvesting, or the number of local weeds infesting the area that have also been gathered. There may also be animal remains, either from insects that made their homes on the plant, or from larger creatures that were caught up in the harvesting process. Stroiz1 examines various types of contamination on cotton fibres and associates them with geographic location, pointing out that significant differences can arise for other than obvious reasons. Peters and Söll2 outline a new scheme for the automatic determination and removal of trash from cotton. Figures 5.1 and 5.2 show how the trash and dust contents are reduced between sliver and yarn by use of the technique.

5.1.2 Wool When wool is considered, more or less the same animal life residues can be expected, for similar reasons, but the vegetable content will represent the remains of grass, twigs or other plant fragments which the sheep has picked up before the shearing operation. There will also be considerable amounts of grease, since sheep exude a fatty combination of organic compounds in the form of a substance known as wool wax. Ryder3 examines the properties of this grease in detail, finding that its presence protects the sheep’s hair from drying out and reduces damage to it from 40

Yarn production

5.1 Reduction of trash content from sliver to yarn (source: Zellweger Ustar).

5.2 Reduction of dust content from sliver to yarn (source: Zellweger Ustar).

41

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weathering, sunlight or rain. It also delays the passage of water through the sheep’s skin, in either direction, and is instrumental to some extent in killing bacteria. Nevertheless, its presence in wool fibres intended for use in textile articles is undesirable and it must be removed; it is, however, described by Ryder as a valuable commodity in its own right.

5.1.3 Silk Silk, in keeping with its luxury image, is altogether a different matter. The fibres, lovingly produced by pedigree worms and cossetted by caring hands, are much cleaner in nature. They make their appearance in the form of a skein of fine fibres (although they may previously have been washed or scoured to remove the silk gum).

5.1.4 Synthetic fibres Synthetic fibres which have never been anywhere near animals or vegetables are scrupulously clean of such contamination right from the start. They may, though, have been subjected to the whims of a careless operator, who has allowed them to overheat, or they may contain residual chemicals from the extrusion stage if they are regenerated, wet-spun or solvent-spun in nature.

5.2

Washing

From the foregoing discussion, it is possible to infer that some elements of cleaning are often needed before fibres can undergo further processing. Washing is the usual way in which this is accomplished, either with water only or, more often, with some form of detergent. Hickman4 reviews the washing stage in the production of cotton and its blends, including materials in the yarn or fabric state, as well as in the fibre stage. He explores the history of cleaning, with an examination of energy, water, steam and labour requirements, and feels that all of these are reaching their limiting values. For this reason, he predicts that the time is ripe for closed water systems as a likely area for imminent innovation. Ripley and Ripley5 suggest that lasers can be used for cleaning and to enable the removal of trash to be accompanied by a bleaching operation, thus reducing a step that can be costly both financially and environmentally.

5.3

Scouring

When more severe cleaning is necessary to remove, for example, persistent dirt from cotton, then scouring is adopted. In this process, an additional agent is added to enhance the cleaning operation, sodium hydroxide being the traditional substance

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used. Lately, the disadvantages of this chemical, both in harming the fibres and in producing environmental contamination (* W-3) (see Table 1.1 for explanation of codes), have been recognised and other approaches have been tried. The most common of these is the addition to the wash liquor of an enzyme, a natural product that is less harmful to the environment and able to bring about cleansing more effectively as well as more rapidly. Section 1 of the Appendix describes some of the many variations of this treatment currently in use. In the case of wool, an alkali is also commonly added to aid in the removal of the greasy matter (politely referred to as ‘suint’), and Section 2 of the Appendix deals with the use of a number of additives used to improve the action of this type of treatment. Even silk has received some attention in the attempt to improve the environmental load of scouring. Krasowski et al.6 recommend the adoption of ultrasound to degum silk, in conjunction with standard degumming methods such as the techniques using Marseille soap, tartaric acid or papain. They report a significant increase in the mass of impurity material removed, with no obvious harm done to the filaments. Some vegetable fibres can suffer from the presence of gum that has to be removed. Bhattacharya and Das7 degum ramie with sodium metasilicate, alone or with other alkalis such as sodium carbonate or trisodium phosphate, instead of using sodium hydroxide. They determine optimum conditions, evaluating the performance of a trial by weight loss, whiteness index and colour strength of the degummed fibres. The new technique is so much better than the older one that bleach may not be needed in many cases, fibres also being much more lustrous and soft. Because the cost is comparable, there is obviously potential for commercial application, as well as for environmental benefits. The conclusion to be drawn from all this work is clear. This cleaning process is responsible, especially in the case of wool, for a serious assault on the environment. The effluent liquors from the plant have often been allowed, until relatively recently in the West and on a still-continuing basis even now in some parts of the world, to flow into rivers without any effort to treat them. The range of chemicals can be extensive and may include toxic, corrosive or biologically modifying reagents (* W-3). As can readily be appreciated, the enormous scope of the textile industry, and the need to remove some kind of impurity from virtually every fibre produced, have been of great concern to environmentalists over many decades. Unfortunately, there is little that can be done to avoid the problem, as we will see later, because most efforts to reduce the damage only lead to an alternative category of pollution. The only real solution is to avoid carrying out the washing or scouring in the first place, but this would inevitably lead to a product that would be totally unacceptable to consumers. Thus, even if a textile manufacturer exerts the utmost care, there is little hope of creating an effluent from the cleaning stage that can be discharged into the local water system without treatment. The types of treatment used and the relative effectiveness of each one are discussed in Chapter 9, Section 7.5.

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5.4

Bleaching

Often, the steps described above are insufficient to bring the fibres to an adequate state of ‘cleanness’ (defined in this instance as whiteness) for consumer satisfaction. In such cases, yet another process must be added, that of bleaching. This consists of a chemical reaction between a reagent (usually an oxidising or reducing agent) that destroys the molecular bonds responsible for the pigmentation that is the source of the coloured, or off-white, state of the fibres. It can be carried out at various points in the manufacturing process, from fibres to fabrics, but the principles of the reaction are identical no matter what the state of cohesiveness of the fibres. Thus, they will be discussed here, at the earliest point in the production line where bleaching can normally take place.

5.4.1 Chlorine bleaching Bleaching can be used for any fibre type, but is not often needed for synthetic ones unless they are blended with natural ones. Traditionally, chlorine has been preferred as a bleaching agent. Huikma8 describes its use, with an account of the effects on fibre and effluent properties of the various chemicals used. He also considers the possibility of reducing liquor ratio and enhancing safety factors, both important in ecologically driven manufacturing, and provides the diagrams shown in Figs 5.3 and 5.4 to illustrate the changes in pH, alkalinity, peroxide and fibre whiteness during batch bleaching. As can be deduced, there are problems with the use of chlorine. First, it tends to be extremely damaging to protein fibres, so that wool and silk are destroyed if left in contact with the reagent at too high a concentration or for too long a time. Second, of more importance from our viewpoint, chlorine is a major cause of environmental harm. The chlorine itself can be dangerous if ingested, can bring about skin irritation or disease on contact, and, even more critically, can produce very dangerous by-products (* W-3), such as dieldrins, during oxidation reactions.

5.4.2 Hydrogen peroxide bleaching Thus, much work has been aimed at finding an alternative means of whitening fibres. The earliest successful substitute was hydrogen peroxide, which, as well as being much milder in its behaviour to proteins, also leaves only water as a residue after reaction is complete. Gürsoy and Hall9 carry out a series of experiments designed to optimise hydrogen peroxide bleaching, in an effort to overcome its disadvantages of slowness and the catalytic degradation of cellulose in the presence of iron, nickel, copper, cobalt or lead ion impurities. They investigate the effects of a range of chemicals at different concentrations and arrive eventually at an optimum bleach recipe. Moe10 provides an overview of the mechanics of the bleaching detergents known as peroxyacids that contain hydrogen peroxide and a

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5.3 Changes in pH and alkalinity during batch bleaching; -----, pH; ––––, alkalinity (source: originally published in Textile Chemist and Colorist, Vol. 31, No 1, January 1999, pp. 17–20; reprinted with permission from AATCC).

5.4 Changes in peroxide concentration and fibre whiteness during batch bleaching; -----, % reflectance; ––––, H2O2 used (source: Textile Chemist and Colorist, Vol. 31, No 1, January 1999, pp. 17–20; reprinted with permission from AATCC).

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Environmental impact of textiles

bleach activator. These compounds are able to remove stains without affecting dyes (unlike chlorine bleaches) because the dyes inside the fibres are inaccessible to them; they are effective against such difficult stains as grass, wine, tea, grape juice and tomato-based foods, yet are compatible with enzymes or optical brighteners, and possess the useful attribute of being able to bleach dye colours produced on bleeding from one fabric to another.

5.4.3 Ozone bleaching Unfortunately, peroxide is very unstable, so can easily lose its effectiveness as an oxidising agent before the bleaching process is complete. A few ways of attempting to overcome this disadvantage are summarised in Section 3 of the Appendix. Ozone is also suggested as a potentially useful bleaching agent. Prabaharan and Rao11 stress that, in the ozone bleaching of grey cotton, moisture and pH level are both very important. They find that optimum conditions, with a compromise between best whiteness and minimum damage, are present at a moisture content of 24% and a pH less than 7, and provide details of the design of a suitable chamber. Figure 5.5 illustrates the effects of moisture content on treatment time and strength loss, both exhibiting a minimum value at about 32% moisture content. Figure 5.6 shows the effects of pH on whiteness, indicating that the value is constant at a pH below about 4.5, then diminishes slightly to pH 7 and subsequently falls off fairly rapidly as pH rises.

5.4.4 New approaches A more recent approach uses an activator, tetra-acetyl ethylene diamine (TAED), commercially sold as Warwick-T, which is recommended by several authors12–15 because it enables bleaching to take place more effectively under milder conditions. Yet another suggestion16 is to adopt ultrasound in the oxidative bleaching of wool to break down various bonds, so accelerating the effect of any oxidising agent used and giving increased whiteness in a lower time with no loss of chemical or physical properties. Lorenz et al.17 use the enzyme protease to bleach wool in an environmentally friendly brightening step, but find that the characteristic canary yellow of wool is not removed.

5.5

Carbonising

Yet another type of ‘cleaning’ (defined as removal of contamination in this case) often used with wool is the process of carbonising. This consists of adding concentrated sulphuric acid to wool, an action which destroys any cellulosic impurities rapidly but is not too drastically harmful to the wool if exposure time is kept short. Developments in the process include the application of a radiofrequency (RF) field to the wool, as described by Baltina et al.18 They claim that with RF

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5.5 Effect of moisture content on treatment time and strength loss in ozone bleaching of cotton;
, strength loss;
, treatment time (source: published in Color. Technol. 117 (2001), p. 100. Reprinted with permission from the publisher, the Society of Dyers and Colourists, Bradford, UK).

5.6 Effect of pH on whiteness index in ozone bleaching of cotton (source: published in Color. Technol. 117 (2001), p. 101. Reprinted with permission from the publisher, the Society of Dyers and Colourists, Bradford, UK).

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irradiation, wool can be carbonised at 100oC, instead of the more usual 120 to 130oC, thus reducing the tendency towards decomposition and yellowing, together with a reduction in energy use, while keeping acid concentration below dangerous (to wool stability) levels. Zanaroli19 suggests applying perchloroethylene to the wool to convert it into a more hydrophobic material and protect it from acid attack, so that the acid that penetrates and destroys the hydrophilic cellulosic impurities leaves the fibres unscathed. The solvent is recovered and recycled, an essential step for successful adoption of a new process in environmentally sensitive areas, though some solvent escape (* A-2) must be expected to take place. The same (Carbosol) process is also described elsewhere20 with the comment that it is not harmful either to the wool or (a claim that perhaps needs to be questioned!) to the environment.

5.6

Drying needs

The fibres need to be dried after cleaning in readiness to be moved to the next stage of production. If the drying equipment is immediately next to the washing or scouring plant, this is simply a matter of a conveyor belt, or its equivalent, to carry them the short distance necessary. This drying step requires large quantities of energy, as mentioned already, and may also produce impurities, such as vaporised solvent (* A-2), decomposition products (* A-3) from the leftover reagents present in small quantities, excess waste detergent and its by-products (* W-3), or other similar substances that are discharged into the air or water. The heat load produced at the outlet from the dryer must also be dissipated, usually by releasing it into the atmosphere inside or outside the plant, with consequent waste of heat energy and contamination of the surrounding area by the above-mentioned impurities. The same need for movement arises when the dried fibres have to be transferred yet again to another location for further processing. At some point, unless the plant is a mammoth one that carries out all stages in an enormous vertically integrated superfactory, there will be a need to transport fibres over a distance too great for them to be shifted piecemeal. Movement in loose form is difficult if not impossible, since fibres would be scattered widely if an attempt was made to ship them in this fashion. To achieve loss-free transportation of fibres in a suitably constrained manner, a baling process is normally carried out.

5.7

Baling

Baling is accomplished by using a large machine to squash down the fibres into a compact package that can easily be transported over long distances. Apart from the usual environmental costs of large machinery, there is little in the way of harm done, but this process represents the first significant occasion on which dirt and noise are a product of textile manufacture. As we will see later in this chapter, in parts of the process where they become more of a nuisance, these can be major

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sources of harm of a type different from any we have met to date, and can cause difficulties of an unusual kind for human beings, as well as for other species. Teutrine21 claims that there is a distinct tendency to move towards automation in baling, and forecasts a time, in the relatively near future, when the industry will insist on only one standard packing method to ensure that highly automated procedures for the opening of bales can be established. In readiness for baling, or indeed for any other stage in the manufacturing process, there is often a need to store the fibres or other textile goods. Because of their chemical nature, storage may occasionally create problems, either of disintegration from mould or other hazards (that will be discussed in Chapter 12) if there is too much moisture, or of cracking if the fibres are too dry. For instance, Brashears et al.22 note that various results produced at the harvesting step can change during subsequent storage in a way that can affect fibre properties and list the needs for successful use of storage conditions. Chun and Brushwood23 point out that storage in moist conditions can reduce stickiness in cotton, but that there is a limiting moisture content of up to about 15% that must not be exceeded if fibre properties (especially strength and reflectance) are to be maintained. Figures 5.7 to 5.9 show changes in strength and colour, sugar content or stickiness taking place as storage time is increased; clearly, it is the effect of moisture content, rather than the storage period, which has greatest influence on these properties.

5.8

Transportation

Textile materials have to be transported by vehicles during and after production. Vehicles are environmentally costly, but they also have a more sinister part to play in the planet’s degradation. Like textile machinery, they are large and complex, with the customary resultant costs, but there is also the matter of fuel combustion to take into account. Exhaust gases, whether from diesel or petrol engines, contain a multitude of harmful emissions (* A-1, A-2, A-3). Many of these are toxic or carcinogenic and compulsory legislation has been introduced in many parts of the world to ban some components (notably lead) by modifying fuel chemistry. Approximately half of all the air pollution today is caused directly by vehicle emissions24 and, although the textile industry is admittedly not responsible for all of these, it must bear a fair share. The exhaust gases that remain after removing (if this is possible) all toxic and carcinogenic products cannot yet be eliminated, and attempts are still being made to reduce their harmful presence by developing improved fuel economy of engines. This improvement, however, is being rendered ineffective as a result of tremendous increases in the number of vehicles being produced annually. The most critical emission gases, in terms of immediate damage, may include compounds of sulphur, heavy metals and organic by-products of combustion, all environmentally undesirable (* A-2). Even if these could all be removed by some miracle of science, the unavoidable production of carbon dioxide, a greenhouse

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Environmental impact of textiles

5.7 Effect of storage time on strength and colour of cotton (source: ref. 23).

gas, would still make the exhaust by-products a source of harm in the long term. Transportation also uses oil extensively, as a lubricant as well as a source of fuel. How harmful this substance can be has already been noted.

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5.8 Effect of storage time on sugar content of cotton (source: ref. 23).

Not only the shipping of goods, but also the transportation of people to and from work, has a contributory effect. Vehicles cannot travel without roads, whose establishment is a major cause of environmental difficulties, from the extraction of the raw materials to the mechanical devices used to lay them down. Their presence also eliminates land on which plants for food (or textile production) can be grown, or on which animals could graze, thus introducing a different category of environmental factor. The topic could merit a separate chapter (or even a whole book), but the fact that it is not exclusively related to the subject of textiles prevents more than a brief commentary at this point. However, its contributory addition to the net ecological cost of textile production cannot be ignored and should be borne in mind.

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Environmental impact of textiles

5.9 Effect of storage time on stickiness of cotton (source: ref. 23).

5.9

Opening

Once the bale reaches its destination, either in another part of the plant or after a longer journey, it has to be opened. The opening process consists of cutting or breaking the baling material, of metal or string, then beating the compacted fibres until they burst apart, sometimes in a near-exploding mass. Nakamura et al.25 define the purpose of an opener in terms of producing fine, uniform tufts and investigate the mechanism at this point in the opening sequence. They find that good tuft formation can have advantageous effects on processability and can

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improve yarn quality greatly. There is often a partial cleaning action accompanying this stage, as impurities are threshed out of the bales so as to be eliminated before the rest of the textile processing occurs. Large quantities of dust are likely to be produced in both of these activities and the surrounding air, in the worst situation, may be filled with a haze that obscures (* A-3) the light.

5.10

Carding

The next step in the sequence, carding, really starts to cause serious dust and noise problems. The potential for pollution can be envisaged from the report of a range of work in progress26 on non-wovens, concerned with carding, air-laying and hydroentanglement, in which a large quantity of fabrics intended for medical textiles, geotextiles, filtration and fluid transmission is concerned. An anonymous author27 provides a chart of cards currently available, with comparisons made of their performance, efficiency and quality of output product, while Merg et al.28 review previous investigations of fibre movement in the carding process. Carding machinery (usually referred to as carding engines) consists of large, complex equipment, with the usual ecological load, but the complexity this time also has the added drawback of making an enormous din and throwing off plenty of dust. The dust may be particles of fibre or may be the trash (waste substances left in contact with the fibres) left over after the partial cleaning of the previous stage. In addition, lubricating oils are often used to reduce this dust production, but these can then bring about their own problems. At some subsequent point, they have to be removed, since they would be undesirable in a finished product and carding oils are yet another undesirable load (* A-2, W-3) on the environment.

5.11

Blending

Blending, the mixing of different fibre types, may take place as an independent step or may be a part of the carding operation. It is carried out either by throwing the different fibre types up in a closed container until they are thoroughly mixed, or by passing them repeatedly through machinery that mixes them intimately by separating individual fibres and replacing them in a different position relative to each other. The net effect in both cases may include some dust production and some waste fibres that are thrown out from the fibre assembly, creating disposal or breathing problems (* A-2).

5.12

Combing and gilling

After carding and blending, fibres may be combed (usually for fine cottons) or gilled (for high quality worsted goods). These processes are essentially similar in nature, in that they both operate by the passage of a number of tines through the

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Environmental impact of textiles

fibre assembly to straighten it and to remove short fibres or impurities. Lubricating oils are used in many cases to prevent fibre breakage as well as to reduce dust. In the same way as those in carding, these oils are removed, becoming an ecological burden (* L-2, W-3). Considerable amounts of waste fibres may also be produced, though they are often recycled to make poorer quality goods. The now-familiar problems associated with large, complex machinery are again evident.

5.13

Drawing

The next step in the yarn production train is the drawing process. In this, thick fibre assemblies are pulled out to make finer ones, known either as tops, slivers or rovings, depending on their final size and (to some extent) the personal preferences of the observer. Essentially, individual fibres or groups of fibres are made to slide past other fibres so as to extend and thin down the rope-like structure in which they are situated. Drawing (or drafting, as it is often known) is usually achieved either by rollers that accelerate each part of the fibre assembly in sequence to bring about the sliding, or by some kind of tine insertion, similar to that used in combing or gilling, for the same purpose. In both types of drawing, energy is used, dust (* L2) and waste fibres may be created, and noise levels (* N-2) can be high, so that the step is the cause of environmental damage of various kinds.

5.14

Spinning

After drawing for one or more stages, the fibre assembly is ready for the last step in yarn production, spinning. This consists of three distinct operations, further drawing to thin the yarn out to the final desired size, twisting of the fibres together to give the assembly stability and winding up to keep the finished product tidily organised. One factor that should always be considered in regard to environmental aspects is that of moisture, because the availability of atmospheric water is crucial for successful spinning, producing better quality yarns that are not likely to be rejected. Price29 investigates the effects of relative humidity on the properties of cotton rotor-spun yarns and his work illustrates the importance of this matter. Several methods of machine spinning have been developed in modern times, the most common ones being the mule (now virtually extinct), ring, cap, flyer and open-end techniques. In all of these, energy is used, waste fibres or dust (* A-3) are produced, lubricating oils (* W-3, L-2) are used to reduce fibre losses, and considerable noise (* N-2) is generated, so involving once more the combination of financial costs with the environmental ones that are the subject of this book. In addition to the simple spinning of a yarn, twisting two singles yarns together to form a plied one is a common operation. The process of twisting uses machines with similar characteristics, as far as environmental costs are concerned, to those used in the initial spinning. So also does the texturing operation, in which yarns are given unusual characteristics that add interest by such steps as false twisting,

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crimping or the knit-deknit process. Each of these adds the extra environmental loading of another machine to the yarn production. Artune and Weinsdorfer,30 in producing a textured polyester yarn, additionally make use of a high-temperature heater to increase the speed of the operation by 20 to 30%. One noteworthy feature of twisting and texturing machinery is the extremely high speed of operation, which can cause very high noise levels (* N-2) and increased dust production (* A-3) compared with those of the spinning operation.

5.15

Noise and dust

Noise and dust are common problems. Both of them will appear again frequently, later in the book, but will be examined closely here. They both cause difficulties for human beings, as well as for the environment, but are distinctly different in nature from any factors so far considered, and as such should be given special recognition.

5.15.1 Noise Of the two, noise is the more difficult to classify with any quantitative accuracy. Noise can be defined as any sound which, because of particular characteristics (such as volume, frequency, speed or harmonic content), produces a sensation of discomfort or pain in the listener. The vagueness of this definition provides plenty of scope for ambiguity, especially in some of the more common sounds heard every day. For instance, the faint buzz of a mosquito in a bedroom, with its potential threat of blood loss, is a guarantee of a night’s insomnia, but for an entomologist, the sound of a mosquito humming to give away its presence may be like music to the soul. Music, too, comes into this category in its own right. The deafening rock music so beloved by some students is an anathema to many other members of society, who prefer to retain their hearing into old age. Similarly, the classical music enjoyed by the author may well be regarded as a special kind of torment by those same students. There are, however, some sounds that are undeniably and universally classed as noise. An explosion, a pneumatic drill, an aircraft taking off, or heavy traffic surrounding a car driving along a high-speed road with open windows, will always be so regarded, no matter what the acoustic tastes of the listener. There are two criteria that should be used in deciding where the sound fits into the desirable/ undesirable continuum used to establish a definition of noise: that of intensity (or volume) and that of ability to please. The two (as for students at a rock concert) may occasionally be in conflict, so that a sound which should be classed as noise because it is painfully loud may be acceptable because it stirs some deep inner emotional chord. Textile equipment can also be included in such a list. If the machine is running smoothly, with a quiet and steady, gentle hum, its sound might be regarded as pleasant by the engineer responsible for its maintenance. If its volume is extremely

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high, to the point where it is painful to the hearing, or if it is emitting a shrill, highpitched note, then pleasure disappears and excessive noise is eventually, if reluctantly, associated with its operation, even by the most dedicated engineer. The test of volume and frequency can thus be applied to any textile machine to determine its position on the noise spectrum. A measure of sound intensity, expressed in decibels, is used to quantify this property. The basis of the measure is an arbitrary allocation of 0 dB(A) as the intensity which is just barely perceptible to the healthy hearing of a young person, where the (A) suffix refers to a system of filters used in electronically weighting the measuring instrument to make its sensitivity comparable to that of the average human ear. As sound intensity rises, the measure increases and, again arbitrarily, the scale is defined in such a way that an increase of 3 dB(A) represents a doubling of volume. The net result of this allocation is that a sound intensity of about 30 dB(A) represents a comfortable conversational tone and one of about 140 dB(A) is loud enough to cause physical damage instantaneously to the ears of somebody exposed to it. In most industrial countries, the danger of subjecting people to high intensity sound has been recognised and legislation exists to limit the exposure time of workers. A typical example uses a derating scale, illustrated in Table 5.1, to define the time a worker may spend in an environment where high noise levels exist. From this can be derived the information that people are not legally allowed to remain in a noisy area at 90 dB(A) for more than eight hours in the working day, and may not be allowed to enter the area at all if sound intensity is 115 dB(A) or higher, with intermediate times being permitted at levels between these two. The legislation also includes the possibility of permitting exposure at higher levels if approved hearing protection is worn, although there are two problems with this loophole. The first is that brain damage can occur via skull bone transmission of vibration even if the ears are protected, which means that the only suitable protection should include a helmet with acoustic insulation incorporated into its structure. The usual hearing protection, earplugs, is useless in preventing harm, even though it meets the requirements of the law. The second problem is that of the machismo image. Because it is regarded by many textile plant operatives as ‘soft’ to protect their hearing, they simply refuse to wear the appropriate devices unless forced to do so by supervisors. So why spend such an inordinate amount of time dealing with the topic of noise? And why are we hearing more and more about the subject of noise pollution? Is it that we have begun to care about the quality of life, lowered by the unpleasantness of noise, or have we suddenly become concerned about the welfare of our workers? Have the level and quantity of noise increased drastically as a result of the modern development of larger, faster, or more complex machinery? There is considerable truth in all of these possibilities, but there is also another reason, much closer to the heart of the true textile manufacturer, the fact that noise costs money. The cost may be direct or indirect, but it is considerable and should be recognised as a genuine environmental reason as well as a financial one.

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Table 5.1 Permissible noise exposure Noise level dB(A)

Permitted unprotected human exposure time (hour)

less than 85 85–90 90–92 92–96 96–98 98–100 100–102 102–105 105–110 110–115 more than 115

No restriction 8 6 4 3 2 1.5 1.0 0.5 0.25 No exposure permitted

The direct cost concerns the nature of noise. It arises as a result of a process taking place in a machine. The process may be a small explosion, as in the internal combustion engine, or frictional contact between two surfaces in a gear train or other type of mechanism. Noise is a form of energy and as such must be generated from a power source. The electricity (or other type of fuel) used up in the process cannot then be harnessed to carry out work, so is wasted. Money is paid out to generate electricity, so the money used to pay for this waste is irretrievably lost from any chance of creating profits. As a final point, the generation of electricity is environmentally costly, and again the waste cannot be reversed. Indirect costs are more subtle. Work carried out in various industrial premises, including textile plants, has brought to light the suspicion that the hearing damage brought about by noise exposure can cause workers to suffer social harm. They may experience increased boredom and loneliness or become withdrawn from social contact as their deafness worsens. In some cases, they may blame the machines that have caused their deafness and deliberately take revenge by harming these perceived sources of a disintegrating lifestyle. Neglect of maintenance, slow correction of operating faults, or even deliberate sabotage, may occur in senseless acts of vengeance. All of these cost the manufacturer money and can exert a cost on the environment in the form of wasted energy or raw materials and excess exhaust gases. The noise that seemed to be of minor importance to our Victorian ancestors has become of crucial significance now that fuel prices have begun to constitute a noticeable proportion of a manufacturer’s costs.

5.15.2 Dust Dust consists of extremely tiny particles of solid materials that are produced when the larger units of these materials break into fragments as a result of mechanical, chemical or biological action. Because of their small size, they are easily blown

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about by air currents or may float in the air for long periods of time without settling. In textile production, they are of two types, the extraneous matter brought into the factory because of its contact with the original fibre sources (as packaging, for instance), and the fragments of the actual fibres themselves produced by the high forces exerted on them during the various stages of production. Once dust particles are released into the ambient air, their subsequent behaviour can cause a variety of problems. The most obvious one is the formation of an undesirable film on every surface in the vicinity. This necessitates frequent cleaning to keep the factory (or the house, because dust is also a domestic problem) looking neat and tidy, requiring extra labour. When the particles fall onto the moving parts of machinery, they can interfere with its successful operation, bringing about an increase in the frictional force between components or an increase in the viscosity of lubricants and, eventually, a breakdown if they are not removed by maintenance. If they fall on the product, of course, they can make it appear dirty, so that it has to be washed, or may even be rejected. All this brings about an additional burden on the environment, from the need to use either detergents, fresh lubricants or cleaning materials and from increased energy consumption. Significant increases in the cost of production can also be caused, a matter that may encourage some manufacturers to take the efforts to reduce dust production more seriously. The second type of problem caused by dust is its health hazard, mainly for human beings but also, to a lesser extent, for other species. Some types of dust are harmful because of their chemical composition, others merely because of their particulate size. Cotton dust, for instance, has long been associated with brown lung (* A-2), a degenerative disease of the pulmonary system in humans and animals, caused by chemical impurities in the fibres, usually with debilitating or even fatal consequences. Asbestos dust, which has a slightly larger particle size, has been shown to be responsible for lung cancer, purely (as far as is known) from the actual dimensions of the asbestos particles lodging in the lungs (* A-2), interfering with their function of cleansing the blood and themselves. Other, less harmful difficulties include the fact that wool dust can set up allergenic reactions and other types of dust can cause sneezing attacks, asthma and related diseases. Apart from any purely humanitarian concerns arising from these health problems, the increased absenteeism brought about as a consequence is, once again, of significance to the thinking manufacturer. Finally, dust can also interfere with the health of growing plants by coating their leaf surfaces (* L-2), so preventing them from absorbing carbon dioxide from the air and releasing oxygen back into it. For all these reasons, limits of permissible dust production are slowly being established in the industrial world and applied to textile processes. Chellamani and Chattopadhyay31 stress the need for workers’ health, to reduce fly and fluff production, and suggest control measures such as moisture addition, infrared lamps at strategic points, floating condensers, acid treatment of roller cots and use of overhead cleaners. Schmitz et al.32 measure dust levels in the German woollen

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industry quantitatively, distinguishing between respirable (total airborne) and alveolar (finely divided) dust. They find that the permissible limit of 6 mg/m3 of total dust is not exceeded in any part of the factory where their testing is performed and that new proposals to limit production to 4 mg/m3 of total and 1.5 mg/m3 of alveolar dust are achievable without any major effort. Van Nimmen and van Langenhoven,33 noting a sharp increase in contamination of fibres by foreign matter, such as plastics or wrongly coloured stray fibres, give an overview of proposed solutions to the problem, with benefits and problems of each one. Kuratle34 distinguishes between dust and trash for cotton, including in the latter term seed-coat fragments and all foreign materials not originating in the actual fibres (such as pieces of cloth, plaster or string), then suggests means of recognising them by optical techniques, followed by mechanical removal. Kechagia and Xanthopoulos35 describe new electronic devices that permit objective evaluation of such quality characteristics as dust or trash content in cotton, noting that their successful detection and removal are crucial in maintaining spinnability, quality, and hence the economic value of the products. We can see that yarn production can be a source of environmental problems from many angles. Human beings are a species that has consistently and deliberately, and to its own detriment, used oxygen to create carbon dioxide, in contrast to plants, which do exactly the opposite. If common sense is to prevail, we need to minimise dust production, as well as to deal with all the other undesirable ecological effects of yarn production as effectively as we possibly can!

References 1 2 3 4 5 6 7 8 9 10 11 12 13 14

15 16

Stroiz, H.M., Melliand Textilber., 1998, 3, 153–156. Peters,G. and Söll, W., Textile Horizons, 2000, March, 19–23. Ryder, M.L., Textiles Mag., 1998, 27(4), 14–15. Hickman, W.S., Rev. Progr. Coloration Rel. Topics, 1998, 28, 39–60. Ripley, W.G. and Ripley, D.A., High Perf. Textiles, 1999, May, 8. Krasowski, A., Muller, B., Fohles, J. and Hocher, H., Melliand Textilber., 1999, 86(6), 543–545 and E 144–145. Bhattacharya, S.D. and Das, A.K., J. Soc. Dyers Colourists, 2001, 6, 342–345. Huikma, W.S., Textile Chem. Colorist, 1999, 31(1), 17–20. Gürsoy, N.C. and Hall, M.E., Int. Textile Bull., 2001, September, 80–86. Moe, K.D., Textile Chem. Colorist, 2000, 8, 79–81. Prabaharan, M. and Rao, J.V., Color. Technol., 2001, 117(2), 98–103. Anon., Int. Dyer, 1999, 184(2), 17. Mathews, A.J. and Scarborough, S.J., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 732–734. Duffield, P.A., Mathews, A.J. and Turner, N.A., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 816–822. Holme, I., African Textile, 1999, June–July, 17–18. Quadflieg, J., Schafer, K. and Hocker, H., DWI Rep., 1999, 122, 544–549.

60 17 18 19 20 21 22

23 24 25 26 27 28 29 30 31 32 33 34 35

Environmental impact of textiles Lorenz, W., Heine, E. and Hocker, H., DWI Rep., 1999, 122, 509–513. Baltina, I., Brakch, I. and Vinovskis, H., Int. J. Clothing Sci. Tech., 1998, 10(6), 89–90. Zanaroli, P., Textiles Panamericanos, 1998, 58(6), 114–120. Anon., Tinctoria, 1998, 95(9), 70–75. Teutrine, D., Chem. Fibres Int., 1998, 48(5), 418–419. Brashears, A.D., Jahn, R.I., Bremer, J.E. and Valco, T.D., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 434–437. Chun, D.T.W. and Brushwood, D., Textile Res. J., 1998, 68, 642–648. Ross, R.D. (ed), Air Pollution and Industry, New York, Van Nostrand Reinhold, 1972. Nakamura, M., Matsuo, T. and Nakajima, M., Int. J. Clothing Sci. Tech., 1998, 10(6), 27– 28. Anon., Nonwovens Rep. Int., 1998, 329, 44–45. Anon., Int. Textile Bull., 1998, 44(5), 43–47. Merg, J., Seyan, A.M. and Batra, S.K., Textile Res. J., 1999, 69, 90–96. Price, J.B., Int. Textile Mfrs. Fed., 1999, 225–228. Artune, H. and Weinsdorfer, H., Int. Textile Bull., 1999, 45(1), 46–52. Chellamani, K.P. and Chattopadhyay, D., Asian Textile J., 1998, 7(11), 86–91. Schmitz, V., Schafer, K. and Hocker, H., Melliand Textilber., 1999, 80(7), 596–600 and E 151–3. Van Nimmen, E. and van Langenhoven, L., Proceedings 1998 Beltwide Cotton Conference, San Diego, USA, National Cotton Council of America, Jan 5–9, 1999, pp. 723–725. Kuratle, C., Proceedings Int. Comm. on Cotton Testing Methods, Bremen, March 1999, pp. 139–142. Kechagia, U.E. and Xanthopoulos, F.P., Int. Textile Mfrs. Fed., 1999, 143–146.

6 Fabric production

6.1

Traditional fabric production methods

Once the yarn has been produced, there are several ways in which it can be made into a fabric. The traditional ones include weaving, knitting and minor techniques such as crocheting, tatting, lace-making and net-making. In addition, fabrics can be made directly from fibres, without passing through the intermediate stage of yarn production. The oldest such technique is felting, but others have been developed in recent decades. These include non-wovens, fibre-to-fabric and film fibrillation. We have also seen the advent of newer techniques, such as laminating, needle-punching, bonding, tufting, stitch-knitting and braiding. Each of these can be examined in turn to assess any influence it may exert on the Earth’s health. In every case, virtually without exception, there is an involvement of mechanical action, creating the risk of dust production, fibre breakage and hence waste. In some of the techniques, though, particularly those carried out by hand, these drawbacks are minimal, solely because the mechanical action is considerably reduced by the slow nature of the process and the consequent reduction in highspeed contact between fibre assemblies and abrasive surfaces. The price paid for this reduction is, naturally, a much lower output.

6.1.1 Knitting Knitting machines are a relatively recent invention, dating originally from the 1400s and developed into a mechanical form in 1598, when Rev. William Lee first produced his replacement for the hand knitting that had been used up to that time. Whether it brought about an increase in attendance at his place of worship, because it provided his parishioners with more leisure time to enable them to take Sundays off, is not recorded, but it certainly improved the speed at which knitted goods could be produced. His work was subsequently improved until, by the middle of the 19th century, the circular machine was invented. In terms of environmental effects, the familiar factors of machine size and 61

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complexity, and of energy consumption, still exist. The need for a lubricant (* W-3) (see Table 1.1 for an explanation of codes) to reduce frictional contact between needle eye and yarn, thus reducing breakage (and hence waste), is also regarded as essential for today’s high-speed machines.

6.1.2 Weaving Weaving, the oldest of the techniques used to make fabrics from yarns, dates from prehistoric times. In those ‘good old days’ it was, presumably, possible to make goods without doing much harm to the planet, but making the same assumption today would be a sad distortion of the truth. Weaving no longer simply happens by shoving a yarn through two other sets of yarns previously strung on a frame between two trees. Nowadays, the warp has to be produced first, by using a winding operation known as beaming to place the warp yarns in the correct location on a beam in readiness for feeding into the loom. In addition, the weft yarns have to be wound onto a shuttle (or other weft insertion device) so that they can be threaded into the fabric in the correct sequence without tangling the entire system so badly that it cannot function. All of these steps require relatively complex machinery, with the associated environmental costs we have already met, and involve such factors as transportation between them or storage facilities that have to be added. Once these preliminary matters are arranged, the loom proper has to be set up in advance of its operation, with its yarns in the correct sequence for production, a process that can be lengthy and tedious. Operation in traditional looms is very damaging from the point of view of the planet and its inhabitants. Vast amounts of force are needed to hurl the shuttle repeatedly and reliably through the shed but, at the end of its travel, the device still retains almost all of the energy originally provided for its propulsion. This energy is then absorbed, with an enormous emission of noise, by allowing the shuttle to slam into a housing at the end of the race. As a consequence, the sound pressure level can reach 110 to 125 dB(A), making the weaving shed notoriously dangerous (* N-2) for the hearing of workers. Noise pollution, however, is not the only disadvantage to bedevil weaving. In modern looms, higher speeds are sought to enhance production rates, bringing about an increase in frictional contact between heddles and yarns and between adjacent yarns themselves. As the warp yarns are only moved in very small steps of progression through the loom, it is clear that they will suffer many such abrasive contacts before finally reaching the point at which they become embedded in the fell of the fabric. This brings about a great reduction in the fabric manufacture rate as a result of the need to keep stopping the machine to repair broken yarns, also increasing the amount of dust or broken fibres produced. In order to eliminate the rubbing, fibre breakage and dust production as much as possible, sizing is used as a means of lowering the effects of frictional contact. Sizing is the application of a size, or binding agent, onto the warp yarns, usually

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before they are wound onto the beam. The effect is akin to a glue that holds the fibres in place. The size may be made of natural materials, principally starch, or may be of a synthetic nature, made from polyvinyl or polyacrylic compounds. Sadly for the planet, neither of these two classes of compound can be allowed to remain on the fabric, because they are very stiff and create bulky regions in the yarns. These would not only be unacceptable to the consumer, but would also create difficulties in subsequent processing steps, such as dyeing or finishing. For this reason, they have to be removed in a desizing operation after the fabric is woven. This step is not easy to carry out, as the size is usually bound fairly firmly to the fibres in order to act successfully. Scouring or solvent extraction are used respectively to remove the two kinds of size and the by-products of these operations are an environmental hazard of the same type as those mentioned earlier in discussing scouring and solvent spinning. Water pollution is especially of concern, since the balance of aquatic species can be totally distorted by the presence of these substances (* W-3). In an effort to reduce pollution, Min and Huang1 describe a one-step design to desize, scour, bleach and mercerise cotton; they study the dyeing kinetics but find that dye absorption is not as good as with the conventional sequence of processes. As a result of these concerns, considerable interest has been shown in sizing and desizing operations. Stöhr2 notes that an ideal size would be one that could be reused repeatedly, indefinitely and without limitation, and deliver optimum sizing results. He feels that such a compound exists, developed in a manner that allows both the size and the water associated with the process to be recycled. The new material, coded as UCF-4, can be removed easily from the fabric with hot water, with no chemicals and reused as long as ultrafiltration is carried out to isolate its synthetic polymer molecules. Figure 6.1 compares the results of using the new size with those from more traditional ones, indicating that it has superior strength and elongation even though it possesses lower hardness. Reports of conference proceedings and of extended research programmes appear in the literature (see Appendix). When the need to remove the size arises, there are suggestions of how best to carry out this step, with enzymatic desizing appearing at first sight to be one of the most promising of these. Some of the relevant papers, both for sizing and desizing, are summarised in Section 4 of the Appendix.

6.2

Other methods

6.2.1 Felting In the methods of producing fabric without passing through a yarn-making stage, felting has to be considered first, not merely because it too predates history, but also because it creates major ecological difficulties in the modern manner of production. Felting occurs because wool fibres, with their sawtooth edge profile, can lock together under conditions of pressure, moisture, heat and agitation, to

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6.1 Comparative behaviour of UCF-4 and traditional sizes; (a) size film performance, (b) cost savings (source: ref. 2).

produce a dense, thick mat that provides an efficient thermally – or acoustically – insulating barrier. In modern machines the process is accelerated beyond the early simple one in order to reduce the time of production from days or weeks to a few hours. This is accomplished by the addition of detergents to the fibres and by the use of mechanical agitators plus superheated steam to enhance fibre contact and heating rates. The result is an unpleasantly hot atmosphere for workers in the production area, a waste of heat energy and an effluent that contains harmful substances (particularly detergent and fibrous matter) that have to be released into the water system (* W-3). As before, the large complex machinery and the high temperatures needed are both expensive environmentally, while the release of the chemicals in the effluent brings about secondary effects in the form of problems for species dwelling in the waterways.

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6.2.2 Non-wovens Non-wovens (often lumped together with fibre-to-fabric) is a term used to describe a number of similar techniques. All of them have in common the fact that they start from a bed of fibres, laid in a parallel, random or crosswise manner and then treated in some way to allow them to be held together in a stable lattice. Techniques for maintaining their integrity include using a glue (* W-3), using heat to melt some of the polymeric components added for this purpose or merely using high pressure to squeeze them together. Some may also use the felting of wool fibres as a binding device, though there must be at least 50% of the bulk in the form of wool to enable successful adhesion to take place. An anonymous author3 describes a spunbonding and spunlacing process using a single-step water-jet method, claiming that this represents an ecologically harmless cost-saving technology with minimum energy consumption, water circulation and downtimes, as well as providing good entanglement. Despite this claim, though, the usual hidden environmental costs are inevitably present.

6.2.3 Minor methods The remaining minor methods of fabric production may be divided into two categories, those in which hand production is carried out and those in which machines are used. Some of the techniques lend themselves to both categories, with a gradually increasing transition to the mechanical methods as old skills are lost by the attrition of the practitioners able to use them. Of the methods quoted, to the best of the author’s knowledge, only tatting is still carried out solely by hand, though embroidery (not strictly a fabric production technique) is done by hand in a slightly diffrent manner from machine embroidery. This technique is currently beginning to enjoy a renaissance, as described by Selm et al.,4 because it is ideally suited to production of the complex structures needed for certain medical implants. Techniques formerly carried out by hand but now converted to machine production, including net-making, braiding, crocheting and lace-making, all need the now familiar complex machinery that pervades the entire industry, with the inherent essential losses to the environment. None of the techniques uses any significant quantity of chemicals in the actual production equipment, though it must not be forgotten that the yarns, which are raw materials of each stage, have already accumulated significant ecological costs before the process begins. In addition, even the techniques carried out by hand need these raw materials and this should be borne in mind when assessing any advantages and drawbacks of a process. The issue of carrying forward a ‘debt’ is one that is often overlooked in attempting to produce an environmental audit. This is a timely place in which to consider the matter.

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6.2.4 Environmental aspects At any stage in a production train, there are factors that do not strictly belong to the step being considered. All the raw materials, for instance, are assumed to be present, as are the items of equipment needed to carry out the step. Nevertheless, each of these components has an environmental cost associated with it that should be taken into account if a complete evaluation of the step is required. The analytical procedure has been described in detail elsewhere5 and leads to a complicated process of iterative calculation that can trace the costs back to the initial step of extracting the minerals for the production of metals or polymers used in manufacturing the equipment from the Earth. Additionally, the costs of acquiring and using the sources of energy necessary to operate the machinery at all stages in the overall production train, from fibre and iron ore, to working equipment and yarns, can be derived. The net result is that no process is entirely free of environmental cost. If one is strictly pedantic, even the production of carbon dioxide by the people breathing can be considered an environmental cost, since this gas is an important source of global warming. When the need to provide them with food, housing, transportation, working space and all the other luxuries they use at the expense of the planet are also taken into account, it becomes more and more clear that human beings are a major source of environmental cost whether or not they even operate any textile operating machinery. The crucial point about this method of analysis is that, if the production at any stage is faulty, the cost to the environment does not just include that of wasting the product of the step where it is discarded, but also the entire production train up to that point. The later in the overall process a rejection occurs, the more cost to the environment is involved. Fortunately, this is a parallel cost to the financial one, leading manufacturers to try to avoid such waste by finding an alternative use for substandard materials instead of rejecting the goods totally.

6.2.5 Stitch-knitting The next production technique, stitch-knitting, is one which is never carried out by hand. There are several versions of the method, including ones with names such as malimo, maliwatt and arachne. In all of these, a layer of fibres is placed on a horizontal carrier plate and is then passed through a piece of equipment that is, essentially, a sewing machine. The machine places stitches into the fibre layer, holding the individual fibres together to form a loose, thermally insulating batt that is soft to the touch. From the environmental perspective at least, needle-punching may be regarded as a modification of this type of manufacture, since it involves the piercing of a fibre layer by barbed needles to bring about entanglement, but this time with no yarns in the needles. In all of these techniques, apart from the cumulative ones incurred and those resulting from the complexity and power consumption of the machinery used, there are normally no added costs to be debited specifically to the method of production.

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6.2.6 Coating and laminating Coating is usually understood to involve the application of a polymeric layer to the surface of a fabric, while laminating consists of the combination of two layers of material, previously produced by another method, by the application of a third layer in the form of a glue or binder. Both techniques are described in comprehensive detail by Fung,6 with an account of their newer methods of production and their many uses. Again, the machinery in both cases is large and complex, with the accompanying environmental costs. In addition, the bonding agent (normally some kind of polymer) has to be manufactured and heated, while the waste products are more than usually inconvenient as they are a combination of different materials (* W-3) that cannot easily be recycled. Bonding, in which the same kind of glue is applied to a fibre batt, has similar drawbacks in ecological terms.

6.2.7 Tufting Tufting, the major method of carpet manufacture nowadays, consists of the insertion of a pile yarn into a premanufactured layer of fabric. The machinery used, as may be expected when a large piece of fabric like a carpet is being produced, is very large in size, requiring high energy consumption and thus placing an environmental load on the planet once more. In addition, chemical compounds (* W-3) are applied to the system to stabilise the relative juxtaposition between the yarn and the fabric and heating is used to set this bonding agent.

6.2.8 Film fibrillation The final means of making a fabric, relatively new but increasing in popularity, is film fibrillation, a process described, for instance, by an author from the Kuralay Company.7 In this process, a polymeric film is produced by extruding the raw material in sheet form onto a flat bed, piercing it with mechanical or ultrasonic energy and simultaneously applying a high tensile force, in order to stretch the film rapidly in the crosswise direction at an unusually large rate of extension. As a consequence of this action and because of the high speed of application of the force, there is no opportunity for the energy applied to be dissipated into the layer and large numbers of local breaks occur. This gives the layer the appearance of a fabric, with many small holes interspersed throughout a continuous solid matrix. Clearly, the environmental costs incurred here, apart from the usual machine operation ones, will be mainly those of making the polymer, as already discussed when the production of polymeric filaments was considered in the Chapter 4. Thus we now have our textile goods in the form of fabrics, whether made via yarns or by a more direct process. Serra-Verdaguer et al.,8 looking at the whole picture, develop bases for eco production and finishing of textiles made from all natural and chemical fibres, and propose criteria for extending a labelling system,

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together with a survey of the main ecological aspects of fabric production and processing. The fabric itself is not yet ready for the consumer. A considerable amount of work must be carried out on it to make it acceptable to our modern tastes. The types of costs incurred by these subsequent treatments are the subject of the next chapter.

References 1 2 3 4 5 6 7 8

Min, R.R. and Huang, K.S., J. Soc. Dyers Colourists, 1999, 2, 69–72. Stöhr, K., Int. Textile Bull., 2002, March, 54–55. Anon, Melliand Textilber., 2001, 7(Sep) 228. Selm, B., Bischoff, B. and Seidl, R., ‘Embroidery and smart textiles’, in Smart Fibres, Fabrics and Clothing, Tao, X. (ed), Cambridge, Woodhead, 2001. Slater, K., J. Textile Inst., 1994, 85, 67–72. Fung, W., Coated and Laminated Textiles, Cambridge, Woodhead, 2002. Kuralay Company Ltd., High Perf. Textiles, 1999, February, 2–4. Serra-Verdaguer, J., Korner, A., Muller, R. et al., DWI Rep., 1999, 122, 579–584.

7 Fabric treatment processes

7.1

Starting material

Modern standards in textile use seldom, if ever, allow a fabric to be sold to the ultimate consumer exactly as it appears immediately after being manufactured. This greige state, as it is known technically, is unacceptable for various reasons and further treatments are required to bring fabrics to the point where they can be used. In modern mills, the foremost aim is to minimise the financial costs of finishing (and all other operations), so it is common for a plan to be drawn up to control the entire train. Arang and Fernandez1 describe a computer program aimed at management, with applicability throughout the entire factory and with emphasis on environmental protection. The treatments carried out after manufacture may be broadly classified as either finishing or colouring. It is also not uncommon for a fabric to need washing before attempting any other processing. Washing, either in detergent or merely in water, has already been discussed at the fibre stage, but may be used at various stages in the manufacture and should be considered as having the same potential means of bringing about environmental damage wherever it takes place.

7.2

Finishing categories

Once a clean fabric is available, the finishing treatment can begin. The type of finishing selected depends on the fibre content of the fabric and the end use to which it will be put. Finishing is usually divided into two types, mechanical and chemical. These can be distinguished by considering the way in which they are carried out. Usually, it is assumed that a treatment is mechanical if it only involves the use of some kind of mechanical action, but it is often accepted that the use of heat and moisture may also be a part of mechanical finishing. Examples of this category of finishes commonly adopted include calendering, beetling, fulling, decating, brushing, raising, shearing, moiré, shrink-proofing and steaming. Wool and synthetic-fibre fabrics are often considered to be the ones needing least 69

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finishing, because of their ability to be produced with many of the desirable features already incorporated. Wool cloths, though, are frequently given a range of both mechanical and chemical finishes, the mechanical ones of most interest being principally aimed at changing thermal insulation characteristics. Fulling is akin to felting and is achieved by subjecting the cloth to heat, moisture and agitation. Its purpose is to close up the tightness of the weave, so that the fabric retains heat better and is less likely to permit air to pass through and cause wind chill. As in felting, environmental costs result from machinery and energy factors, as well as from the discarded wash liquors (* W-3) (see Table 1.1 for an explanation of codes).

7.3

Mechanical finishing

7.3.1 Brushing, raising and shearing Brushing, raising and shearing are usually considered together; Korner2 explains the objectives and principles of the processes, together with discussion of the factors influencing them and the requirements for their successful operation. Brushing is, as its name implies, the passage of the fabric over a surface that brushes the fibres to lift them slightly out of the bed of the fabric. In this way, the amount of air enclosed is increased and, because trapped air holds heat well, so is the thermal insulation. Raising takes the process one step further, lifting the fibres still more by brushing them so roughly that the actual weave pattern is obscured. This not only increases insulating capability still further, but can conceal a sleazy cloth to some extent, so an open weave, with its inherently lower strength, can be disguised as a better one. Unfortunately, one side effect of this degree of raising can be an even greater reduction in strength, as the integrity of the fabric cohesion may be disturbed, thus shortening the life expectancy of the fabric. In such cases, there is another kind of environmental cost, that of the premature scrapping of the fabric, to add to the familiar ones of machinery and power consumption. There may also be a cost associated with the breakage of individual fibres, producing a certain amount of waste that cannot be reclaimed for any really valuable or useful practical purpose in view of the extremely short lengths of the fibre segments removed. After raising, the appearance of the fabric tends to be rather ragged, because of the rough treatment it has received. For this reason, shearing is then carried out. This is a means of cutting off some of the fibres, so that they are all at a uniform height above the fabric surface, by passing the cloth through blades resembling those of a cylinder lawn mower. The side effect, which is a large quantity of waste fibre, is obvious and produces an inevitable environmental cost.

7.3.2 Moiré In moiré finishing, in which a fake watermark is embedded into a synthetic fabric in an attempt to make it look like a silk, heat and pressure operations take place,

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with one portion of the fabric being forced to run counter to another by passage around suitably arranged cylinders, so that a frictional effect is produced that marks both of the contacting sections of the cloth. Decating, calendering and beetling can also be considered in the same category. Each of these treatments involves the application of pressure, with or without heat and/or moisture, to a fabric. The purpose and the fibre types to which the respective finish is applied are different, but the basic principles (and the ecological effects) are the same in each case. Machinery and energy factors are present once more and, when steam is used, some waste heat is evident when it is allowed to escape onto the cloth.

7.3.3 Mechanical shrink-proofing Shrink-proofing as a mechanical finish uses the overfeed principle, in which damp fabric is pushed onto the pin frame of a tenter (described in Chapter 11, Section 11.3) then subjected to sideways tensile stress while drying occurs. Energy losses are high, as described later, but the resultant fabric tends to be stronger and is less likely to be discarded. The fabric is also unlikely to be thrown away as waste prematurely, as it would be in the absence of shrink-proofing when a garment made from it might no longer fit after washing.

7.4

Chemical treatments

7.4.1 Chemical shrink-proofing Chemical treatments associated with shrink-proofing are normally used in modern plants and can be considered as the first example of a chemical finishing process. The mode of operation of such a process is to fill the interstices between the yarns of a fabric with a reagent that blocks the spaces so that the yarns cannot move into a closer juxtaposition. The process adopted may vary, either using impregnation with various resins, or by cross-linking with (for instance) dialdehyde, glyoxal and urea–formaldehyde. In both of these types of treatment, waste effluent of one or more of these chemicals (* W-3) is inevitable, and its subsequent discarding into the water environment will, just as inevitably, create a pollution problem. Xu et al.3 apply durable press to cotton in a one-step (and hence less polluting) method and compare the outcome to the more usual two-step process. They test results by crease recovery angle and strength measurements, finding that the two-step technique is better for crease recovery, but not as good for strength retention because of the longer curing times needed. These will, naturally, also increase environmental costs, offsetting to some extent the benefits imparted by this modification of the processing train. Optimum conditions for the two-step treatment are quoted as 4.3% citric acid and then 1.7% butane-tetracarboxylic acid. Cheng et al.4 attempt to improve the easy-care finishing of silk by using a multifunctional epoxide that reacts with the tyrosine in the silk to reduce the

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chemical activity of the fibre. Little or no change in wetting properties is evident, but the rate of hydrolysis in alkaline solution is very much lower after treatment. An anonymous writer5 reports the production of washable wool by easy-care finishing using oxidative or cross-linking techniques, noting that the process reduces shrinkage from about 30% to about 2%.

7.4.2 Water resistance A similar end result occurs in the various methods used to provide water resistance. The type of reagent involved depends on the degree of resistance needed, whether merely for protection against light showers, or against heavy storms, or to prevent all aqueous liquid entry in, say, a garment for protection against chemical or biological warfare reagents. In addition, there is considerable interest in the development of finishes that are resistant to liquid water, but allow moisture vapour to pass through. This treatment compensates to a considerable extent for the main disadvantage of traditional storm-resistant fabrics, the tendency for the people wearing them to be wetter from their own perspiration than they would be from the actual rain being kept off their bodies. The types of chemical used (and the resulting effect on the environment) vary, but are typified by insoluble metallic compounds, paraffin or waxes, bituminous materials, linseed or other drying oils and combinations of all these substances. Application in each case is usually achieved by padding, or passage through pressure rollers under or near the surface of the treatment liquid. Again, the inevitable machinery and energy factors must be accepted, but there is also the added problem of disposal of the chemical reagents. Paraffin and similar waxes are relatively harmless and can usually be reused easily, but some metallic compounds, oils and bituminous materials may be highly toxic (* W-3) and should only be released after considerable dilution. Even then, all of them are harmful in some degree and should be regarded as undesirable. In this context generally, the industry has begun to sound warnings. Lal6 expresses concern about the effects of pollution on the environment and Soljacic et al.7 propose that a system for ecoacceptable finishing ought to be developed. Gulrajani8 feels that the Indian chemical finishing system is already environmentally sound, but is antiquated. Mathew9 suggests that the use of ultrasound in all applicable wet processing steps, such as the preparation of sizes, emulsions, dye dispersions and thickeners for printing, would be beneficial to the planet’s well-being because it can reduce the amount of reagent needed. Duschek10 describes the mode of action of fluorocarbon polymers and the ability, by using a new technique, to apply such a finish in a lowemission manner (about 90% lower) to maintain emissions well below legislative standards and with no thermal after-treatment. How well the rest of the industry follows strictures for ecological responsibility is not too encouraging, as we will shortly see, but all the chemical finishes currently in vogue will be considered here first. In an unusual approach, Barton11 reports the

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possibility of ‘intelligent fabrics’ being developed. These would have fragrances, moisture, antibacterial finishes or thermal modifications incorporated into their structure to provide continuing effects. Until they are commercially realisable beyond the relatively few underwear applications presently available, the industry has to rely on more familiar techniques. Moisture vapour permeability, in conjunction with liquid water resistance, is currently ardently sought as a kind of ‘philosophers’ stone’ in textile science. The elusive ability to allow complete moisture comfort with the total exclusion of all liquid water and the total capability of perspiration moisture to escape, has not yet been developed. The principle on which a successful technique can be expected to operate is a simple one, the fact that there is a significant difference between the molecular sizes of liquid and vapour aggregates of water. Unfortunately, we do not yet have the ability to control the size of fabric apertures to the necessary degree of accuracy. The methods of approach currently in vogue include hydrophobic finishes, coatings, and laminations of microporous films or membranes. More details of the latter two are provided by Fung.12

7.4.3 Durability Hydrophobic finishes tend to suffer from a serious defect, in that the finish slowly disappears during extended use. Thus, a raincoat which gives adequate protection against showers when bought may, after a few laundering or dry cleaning treatments, be less than satisfactory and leave the unfortunate wearer soaked. In terms of environmental damage, the application of the water-resistant finishing agent, usually consisting of a reagent similar to those mentioned above in connection with liquid water resistance, is a problem both at the manufacturing stage, when the surplus chemicals are flushed into the drain (* W-3), and after use if the garment is thrown away prematurely because it is no longer of any value for its intended purpose. The type of finish will be governed by the degree of water resistance required, but all of those currently in use tend to be slowly lost with time and this approach is not now regarded as having any real future. Because of this, other solutions have been attempted. One of the earliest of these was the traditional oilskin often used by seamen and cyclists. This consists of a topcoat made from a fabric of cotton which has been saturated with an oil (usually linseed or some related substance) and heated to bake, and hence polymerise, the oil. The actual extraction of the oil, as with all oils, carries the environmental cost mentioned already, and the baking process is likely to produce toxic gaseous byproducts (* A-2) as a result of the high temperatures needed for polymerisation. The garment, too, is usually not completely satisfactory, as anyone who has cycled in one will attest. The inside of the oilskin after pedalling strenuously up a steep hill leaves the cvclist in a sad state of drenched discomfort from perspiration that stays with him, entrapped by the impermeability of the oilskin, for the remainder of the journey.

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7.4.4 Membranes The next type of solution to be discussed is the membrane, specifically described in a waterproof and breathable application by Bajaj;13 the technique is most familiarly typified for the general public by Gore-tex products. In these, a thin membrane of microporous material of polytetrafluoroethylene (PTFE) is sandwiched between two layers of fabric, usually polyester, to reinforce the fragile membrane and prevent it from shredding. The production step involves making PTFE and polyester fabrics, accompanied by all the usual difficulties in polymer manufacture, and in producing an adhesive substance to hold the layers together. The adhesive will impose an environmental cost, as will the subsequent process of applying it by machinery. The approach is not completely satisfactory, as the excellent barrier performance preventing water ingress is not accompanied by a total capability to allow perspiration to escape. In addition, the fabric itself can suffer from delamination, leading to premature rejection. The author has experienced both of these drawbacks, having used such a fabric and redesigned the construction of the sandwich material to minimise the latter problem, in a design for the surgical operating theatre gowns illustrated in Fig. 13.2. As always, prematurely discarding a product is an added load on the ecological equilibrium, so the use of this type of material in water-resistant garments is not to be recommended unreservedly.

7.4.5 Coatings A compromise between the techniques of using a microporous membrane and a finish is the adoption of coatings. In these, a microporous material is applied to the external surface of a fabric (usually polyester again) and is adsorbed directly onto the fibres. This method of production still depends on manufacture of the polymeric materials, but does not involve any separate adhesive, any separate application process or any risk of delamination. It has been shown to be more satisfactory from the ecological perspective. Steps are in progress to bring about further technical improvements to allow it to compete adequately on the basis of performance and financial factors. Kubin14 traces the development of coating technology and provides detailed information on recipes, process operation and properties imparted for a range of types.

7.5

Other finishes

A wide range of other finishes should also be considered. These may be categorised in the areas of treatment designed to modify the nature, appearance or feel of the surface for aesthetic reasons, those designed to lengthen the life of the fabric and those intended to provide enhanced consumer satisfaction. The first type includes softening, stiffening and antistatic finishes, while the second may be exemplified

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by abrasion resistant or antimicrobial finishes. The third category has become of much greater importance and includes such attributes as a built-in resistance to creasing, flame, oil and stains. It can be deduced that there is likely to be some form of crossover between advantages imparted by the three types.

7.5.1 Softening and antistatic treatments Softening and antistatic treatments both use the same type of reagents, such as quaternary ammonium compounds, to achieve their effect. These substances are manufactured in a process that has the customary environmental costs of chemical agent production. Application is seldom, if ever, completely perfect and quantities of the reagents are washed (* W-3) into the discard stream from the plant, affecting the local water purity. An anonymous author15 stresses the enormous need for softeners and discusses problems of sewability, yellowing and shearing stability that can arise from softener use.

7.5.2 Stiffeners Stiffeners, such as starch or vinyl compounds, need to be produced, either by extraction from cellulosic plant sources or by a chemical reaction and again are to some degree discarded in the waste stream (* W-3). A related type of finish is that of mercerisation, the process by which cotton is made more lustrous and stronger by short-term immersion in concentrated sodium hydroxide. The alkali is potentially an environmentally harmful agent if discarded into water or onto land (* W-3, L-2), so alternatives would be useful. Min and Huang16 provide details of a one-step process that includes desizing, scouring and bleaching as well as mercerising, but find that poorer dyeing results are produced by its application. Figure 7.1 shows the graph they derive for their cotton fabrics relating dye concentration (a) to dyeing time (t) on logarithmic axes. The colour level after a given time, but not the slope of the curve, is influenced by temperature, as may be seen in the diagram. Rathi,17 using enzymes, and Ramaswamy et al.,18 with simultaneous bleaching, also provide suggestions for mercerising, but imply no loss of properties as a consequence of the action. Figure 7.2 shows bar charts derived by the latter authors indicating the effects of bleaching and mercerising on dye uptake. Abrasion resistance is imparted by the application of some form of lubricating agent to the surface of the fabric. The substance chosen may be an oil, wax or a thermoplastic resin, with results and side effects comparable to those mentioned above in connection with these types of finishing agent. In extending fabric life by enhanced biological resistance, some consideration must be given to the hazards likely to be encountered by the fabric in use. There may, for instance, be a risk of insect damage, especially if wool fibres are present. If the fabric is likely to come into contact with the ground, or is to be used in a damp place, then the chances of rotting may be of concern. If it is to suffer long periods of exposure to the elements,

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7.1 Relationship between dye concentrations (a) and dyeing time (t) for cotton fabrics; dip temperatures:
, 20ºC; ∆, 40ºC;
, 80ºC; ¸, 100ºC (source: JSDC 115 (1999), p. 70. Reprinted with permission from the publisher, the Society of Dyers and Colourists, Bradford, UK).

especially where bright sunlight is present, then degradation by ultraviolet radiation is a possibility. Finishes have been designed for all of these and are frequently applied in the modern textile industry.

7.5.3 Microbiological-resistant treatments Resistance to biological agents, ranging in size from insects down to the smallest bacteria, can be introduced into textiles in the finishing process. Insect resistance is incorporated into a fabric by germicides (such as metallic salts), resins or organic mercury compounds, with the optimum substance toxic to the specific insect or mildew, and so on, being chosen to minimise damage in comparison with that suffered by an unprotected fabric. The most usual example of a harmful insect is the wool moth, which can degrade large quantities of fabrics by making holes in them. The moth operates by feeding on the disulphide links in the protein of the wool and has traditionally been combated by the use of dieldrin. This substance has been designated as harmful to humans because of its toxic and carcinogenic nature and is now banned in many countries. More recent techniques rely on less effective (in the opinion of many experts) substances, such as fluorides, compounds of antimony or chromium, dyestuffs (mitins or eulans) or formaldehyde to protect the wool (* W-3).

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7.2 Effect of bleaching and mercerising under various conditions on dye uptake of cotton fabrics (source: Textile Chemist and Colorist, Vol. 31, No 3, March 1999, pp. 27–31; reprinted with permission from AATCC).

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All of these compounds, from dieldrin to its modern substitutes, constitute a load on the ability of the planet to renew itself in a healthy manner. The chemical agents (especially the more modern ones, which must be used in far higher concentrations than dieldrin) can produce adverse effects in many species and are toxic to humans. Other insects, such as carpet beetles, are dealt with in a similar manner, with comparable results. The protection of textiles against insect damage is not without effect on the world around us, and the extended life of garments made from susceptible fibres (allowing them to be kept for longer periods instead of being thrown away as a load on the environment) should be weighed against the risks of danger or harm to the various affected species of the planet. An exactly similar argument also applies to rotproofing agents, such as metallic salts, condensation resins or cellulose acetate, which function in the same way to prevent damage by microbiological agents, such as moulds or mildew that are present in soil or damp locations. These treatment substances, which operate either by preventing contact between cloth and the harmful agent or by inhibiting microbiological growth, also create hazards to planetary species when they are discarded (* W-3). Efforts are made to minimise the amount of all of these reagents sent to waste, but the best processing conditions, unfortunately, can still bring about appreciable risk of damage from effluent chemicals. These smaller-scale undesirable biological entities have aroused interest because, if they cannot be removed, they can either destroy the fabric or can make it unacceptable, both of which lead to environmental stress as a result of premature discard. In general, the same types of chemical reagent have been used in the past to deal with problems on this scale as have been adopted for controlling larger pests.

7.5.4 Ultraviolet resistance Ultraviolet resistance is imparted to fabrics by protecting them with an agent that absorbs radiation in the relevant portion of the electromagnetic spectrum. Instead of attacking the chemical structure of the fibres, the incident radiation uses its energy to bring about an increase in the vibration of specific bonds in the absorbent molecule, thus allowing the fabric to survive unscathed. Once more, these substances (including amines, sulphonated or benzoyl compounds and other complex organic reagents) are unsafe (* W-3) if released into the water system and impose difficulties on ecological protection capabilities.

7.5.5 Easy-care finishes The third category of treatment purposes is that of consumer satisfaction (including protection). When it is of importance, easy-care finishes such as crease-resistance, soil or stain resistance or repellency and flame resistance are crucial. Crease-resistance depends on the application of an agent capable of allowing the fabric to retain a preset shape by ‘locking’ the molecules into a

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7.3 Bonding changes during crease-resistant treatment. (a) Original fabric with unstretched bonds, (b) crease in fabric; bonds stretched, (c) bonds broken chemically, (d) bonds reformed chemically in less stressed positions, (e) flattening of crease produces restoring stresses in bonds.

particular conformation, as illustrated in Fig. 7.3. The initial molecular structure is placed into the desired form (a crease, pleat or a flat surface, for instance) and a reagent (or its precursor mixture) selected from urea–formaldehyde, melamine– formaldehyde, epoxy resin or a vinyl compound, is spread onto the cloth. The combination is then heated to bring about the essential reaction, so that either the molecular interstices are filled by the polymerised substance or there are added cross-linkages formed between molecular chains. When a potentially creasing force is applied to the fabric in use, the resulting distortion of the fabric is resisted by the blocking action of the space-filling layer or the stretching of the bonds, and the set shape of the fabric is quickly restored once the distorting force is removed. Formaldehyde is a familiar carcinogenic agent, so that any residual amounts of this substance that remain uncombined with the urea and are discarded are dangerous on being released (* W-3) into the environment. In addition, the baking process can bring about the production of gaseous toxic substances (* A-2), released into the atmosphere as part of the emissions from the treatment process. Saraf and Alat19 address this particular concern with their paper on new developments in the search for alternatives to formaldehyde as a cross-linking agent in resin-finishing of cotton and of cellulose/polyester blends. They investigate the effectiveness of natrium at various temperatures on crease recovery and yellowing.

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Vukusiae et al.20 recommend the use of polycarboxylic acid with a mixed catalyst as an ecologically sound alternative, but find that it is too costly and discuss means of overcoming this defect. The ability to repel oily stains is provided by the application of compounds such as silicones or organofluorochemicals to the fibres. These materials function by preventing any permanent attachment between the hydrophobic molecules of the oil and the fibre molecules by interposing an oleophilic layer between the two. As usual, the substance is a toxic agent, so its effects are felt if disposal (* W-3) in waste water is attempted, and its manufacture also involves environmental risks. Scott21 provides details of a coating treatment that can make fibres resistant to water, oil, grease and solvent staining and which is durable in use. The coating has been applied successfully to cotton, synthetic and glass products, at the fibre, yarn or fabric stage, by gas plasma techniques. An anonymous writer22 also mentions a water-resistant coating that can be used as an alternative to polyvinyl chloride (PVC), based on a copolymer of polyolefin and ethylene vinyl acetate, that is claimed to be ecofriendly on the basis of using no chlorine or bromine. Vohrer23 notes that, as a result of societal demands for textiles produced by environmentally sound methods, plasma treatment (the application of an electrical discharge in a gaseous medium) is likely to become more common in the near future.

7.5.6 Flame resistance Flame resistance is a topic that has occupied the attention of textile scientists for several decades. It is an inevitable end result of exposure to an open fire that a material which, like many textiles, contains a large amount of carbon in its molecule, may well burst into flame. If it does, the person wearing the material is likely to suffer burns, while others in the vicinity may be overcome by the fumes emitted or may be trapped in a building because they are unable to see through the smoke evolved. The methods adopted by the industry as far as possible to counteract these risks are, unfortunately, somewhat suspect. The principle involved, as a result of legislation enacted in many countries, is one of preventing ignition or, more often, slowing down the rate of spread of any flame occurring. The first of these approaches, though apparently unimpeachable, is seen to be flawed on practical examination. The finishing agent used, usually a compound of phosphorus, nitrogen and/or a halogen, may (as is normally the case for most finishes of any kind) be removed by extended care procedures, such as washing or dry cleaning. Thus, after a period of use, an article thought to be resistant to ignition can in fact burn and a false sense of security may be engendered in the owner. Finishes designed to slow down the rate of spread of flame, in the same chemical categories, suffer from the same defect, but are also dangerous from another, more important, perspective. If, say, a cotton fabric ignites, it burns quickly and there is little time for intense heat to be produced in any one location. If it has been treated to slow down the rate of flame spread, the hot flame remains in contact with the

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fabric for a longer period of time, so heat buildup can occur in a small area. The resultant damage to an arm covered by the cotton will be more severe and can include third degree, rather than superficial, burns that will leave permanent scars at least and may well damage the arm so badly that a skin graft is necessary. If, alternatively, the flame spread rate reduction is achieved by blending with a (less rapidly consumed) synthetic fibre fabric, this fibre can melt and stick to the skin, causing even greater problems. Both categories of finish are inherently undesirable in the ecological sense. The reagents themselves are harmful when discharged into the waste water stream (* W-3), and may also cause skin reactions in some people. Disposal of the garments after prolonged use will allow leaching of any residual finish to take place, with further harm resulting once it reaches the underground water table. The end products of the combustion reaction if burning does take place are more dangerous for a treated fabric than for an untreated one, since there is an additional evolution of harmful chemicals such as hydrogen cyanide, halogen compounds or oxides of nitrogen, as well as a higher concentration of carbon monoxide as a result of incomplete combustion induced by the presence of the finish (* A-2). In addition, smoke density increases significantly in the presence of flame-retardant finishes, a factor that not only increases danger from a fire by preventing people from seeing an escape route (* A-3) but also adds to the pollution resulting from the combustion.

7.6

Colouration

One of the most troublesome current areas of concern in the textile industry is the pollution brought about by the colouration processes of dyeing and printing. Although they are not, strictly speaking, finishes in the generally accepted sense of the word, colouring agents are normally dealt with in this category. The main problem with the compounds used for applying colour is the fact that they are almost always, especially with reference to the original synthetic dyestuffs developed in the 19th or 20th centuries, highly toxic (* A-2), carcinogenic or (for good measure) both. Until fairly recently, they were released freely into the waste waters from the plant and could be seen boldly proclaiming their presence to all and sundry as a brightly coloured, but somewhat nasty, area of water. Of late, however, the industry has been trying valiantly both to reduce the effluent emerging from its dyehouses and to develop less harmful dyes but, although there has been some success in both of these aims, there are still large amounts of dangerous quantities of rejected dyes (* W-2, W-3) released from the washing treatment used to remove excess colour before continuing the fabric production train. Benisek24 provides a summary of ecofriendly dyes and packaging materials, while an anonymous author25 reviews a seminar devoted entirely to environmental issues, with particular reference to natural dyes, thickeners for printing paste and ecofriendly finishing.

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7.6.1 Dyeing with natural dyes The use of natural dyes, as opposed to synthetic ones, is often touted as a means of reducing environmental damage. Bhattacharyya and Acharekar,26 for instance, feel that the dyeing of jute with natural dyes to eco-specifications is now commercially feasible. There are, according to one author,27 benefits in lowered energy use, water consumption and allergenic effects, accompanied by easier biodegradation, though the problems of availability and colourfastness are noted. More serious concerns are voiced by Achwal,28 who points out that colour variation in natural dyeing can be so great that redyeing is needed, thus increasing the use of energy and water, with a consequent increase in both financial and ecological cost. Other writers29 add the observation that the necessary amount of dyes required would denude nature to an unacceptable extent, thus offsetting any possible advantages.

7.6.2 Synthetic dyes For all these reasons, recent work has tended to seek new means of adopting synthetic dyeing techniques with lower planetary loading, a matter of increasing importance according to one writer,30 who notes that the initial cost is high enough to discourage many manufacturers. However, the long-term savings in water, dyestuff, energy and waste treatment costs are appreciable. A crucial change in dye chemistry is being sought by several authors, mainly as a result of the harmful effects of certain dyestuffs, while a second approach suggested31,32 is the use of plasma treatments (low-temperature electrical gas discharges, such as those that can be achieved with a corona glow) to accelerate dyeing, increase brightness or improve penetration and hence fastness. Figure 7.4, taken from the former paper, shows the effects of plasma treatment on the dyeing rate (for various natural dyes) associated with the use of oxygen, ammonia and carbon tetrafluoride sources. It can be seen that there is virtually no change between treatments as a result. Similar plasma treatments have been used to increase fibre quality in wool combing (with less waste water),33 or to modify wool surfaces in other applications,34 and thus are worth examining as a technique for improving dyeing. Detailed information on all of these areas can be found in papers summarised in Section 5 of the Appendix.

7.7

Pollution aspects

The discharge of pollution from colouration processes occurs in two critical ways. First, when the dye is applied to the fabric (or to some other fibre assembly if dyeing is carried out at an earlier stage of the production), the colouring agent is not all picked up by the fibres. There are inevitably some residual amounts of dyestuff that cannot be adsorbed and, although efforts are currently made to recycle them (as detailed in Chapter 13 and the Appendix), there are large quantities that cannot

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7.4 Effects of different types of plasma treatment on dyeing time of wool with various natural dyes;
, untreated; ∆, oxygen plasma;
°, ammonia plasma; , carbon tetrafluoride plasma (source: ref. 31).

be reused, either because the particular shade is no longer applicable for the next fabric batch, or because the dilution is too great to make recovery economically viable. It is possible to distinguish to some extent between the different types of dye used, in order to allow some estimate of the relative harmful effects of each one to be made and a comparison of the chemistry of various dye types is of value in this exercise.

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7.7.1 Acid and cationic dyes The simplest dye types are probably the acid and cationic (or basic) ones. These are applied directly to the fabric and are obtainable in a wide range of colours. However, they tend to have poor fastness, bringing about premature rejection of the dyed product (and hence early pollution) and many of them are carcinogenic or otherwise toxic (* W-3). More recently, substantive direct dyeing has been introduced with the aim of increasing fastness and hence reducing waste, a beneficial step from the ecological as well as financial point of view. Azoic dyes generally need low temperatures (for which energy is expended) and use toxic (* W-3) chemicals for their production. Mordant dyes, which depend on an auxiliary compound to provide fastness to light and washing, suffer from the fact that most mordants are heavy metals (notably chromium) that can bring about serious environmental problems once the excess reagent is discarded. Recognising this drawback, Parton35 suggests that alternative dye types should be sought and recommends reactive dyes with an increased range of colours without the chromium effluent. These combine chemically with the fibre, tending to be exhausted reasonably effectively. Disperse dyes, used in colouration of synthetic fibres, tend not to be as wasteful as are some other types, because the dye is insoluble in water but soluble in the fibres, so is less of a problem to extract once the process is complete. Sulphur dyes, also insoluble in water, can similarly be removed from waste liquors slightly more easily than most other types. Thus, both of these provide a means of reducing pollution. Vat dyes are applied as a colourless precursor and need the presence of oxygen to develop their colour; they may therefore be more difficult to control (since the precise depth of shade cannot be seen until dyeing is complete), with the resulting possibility of increased chances of rejection of the dyed goods. Finally, solution dyeing, in which the colour is developed by solubility of the dyestuff directly inside a synthetic fibre, is possibly even more easily prevented from polluting the water supply.

7.7.2 Relative hazards In all cases it must be remembered that the actual chemicals from which the dyes are made may be harmful in varying amounts, so that the escape of a small quantity of an efficiently applied dye type may be more dangerous than the leakage of a larger quantity of one that cannot be controlled as well. The human factor, too, should not be ignored. If the technologist carrying out the dyeing operation makes a miscalculation or fails to follow instructions properly, even the most efficient dyeing process can lead to disastrous production of large quantities of dangerous waste material. Shukla36 derives a list of the chemicals used in textile auxiliary treatment in 1997, noting that there is a shift towards environmental concerns in the selection of chemical agents used. His list incorporates not only dyeing and printing auxiliaries, but also those used in softening, flame resistance, oil repellency,

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antifoaming agents and fibre-protective substances of various types. Efforts to reduce the emission of harmful agents are in evidence, as found in material also included in summarised form in Section 5 of the Appendix.

7.7.3 Supercritical dyeing Other approaches are being sought. Lennox-Kerr37 discusses new developments in dyeing with supercritical fluids, especially in attempts to reduce the current high cost that makes the process not economically viable. The theory behind this approach is that, if a substance that is normally a gas at room temperature is subjected to extremely high pressure, it can be liquefied. In this state, if it happens to be a suitable solvent, it can dissolve the chemical in question (a dyestuff in this case) and, when pressure is released, the liquid will evaporate, leaving the dissolved substance behind in the position to which it has been carried (i.e. the interior of a fibre in this example) while in solution. Lennox-Kerr notes that, in place of the most commonly used supercritical fluid, carbon dioxide, others like alkanes, ammonia, carbon monoxide and nitrous oxide, should be or are being tried and gives a summary of the process. Kawahara et al.38 examine the behaviour of a new type of polyester, made by a high-speed spinning technique, during supercritical dyeing with carbon dioxide. In comparison with conventionally produced fibres, the new polyester (which has comparatively large crystallites and low birefringence) is superior to the conventional one in dye uptake at low temperatures, but not very different at higher ones. The reason deduced for this behaviour is that fibre swelling in the supercritical fluid needs to reach a certain level, after which the dye diffusion is promoted and the larger crystallites mean that the new fibre reaches that level at a lower temperature.

7.7.4 Plasma treatments Özdogan et al.39 use plasma polymerisation to increase the dyeability of cotton in low temperature media. The treatment introduces to the anionic surface a cationic phase, and the resulting enhanced dyeability reduces water consumption, pollution and amount of dye needed. The authors suggest that there may be a benefit from developing modified dyestuffs to take advantage of the new technique when commercial applications are in progress.

7.8

Printing

In turning to printing, we should note first that virtually all printing processes use the same reagents as do dyeing treatments. Thus, the identical potential for harm exists in printing and the same relative risks for each type of dye used are also present. There are, though, added problems involved in printing and, in partial compensation, some minor benefits too.

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7.8.1 Principles Printing involves the localised application of dyestuffs to selected areas of a fabric. In order to prevent the dyes from straying outside the desired area, some means of lessening the ability to move must be incorporated. The aid used is a printing paste, a thick substance such as starch, gum or resin that increases greatly the viscosity of the colouring agent applied. This thickener is, of its own accord, a pollutant and can cause water pollution (* W-3) when excess amounts are discarded after the printing process is complete and the equipment is washed in readiness for the next batch, of a different colour. There is an awareness of the problem; Galgali40 proposes, for example, that ecofriendly pigments (ones causing no evolution of carcinogenic formaldehyde) should be adopted, a step that appears slow to be accepted. Zacharia41 collects kerosene from printing by using a cool chimney effluent and separates the substance from water in order to lower pollution. In compensation for the increased pollution risks, though, is the fact that a printing paste can often be more easily collected, with lesser amounts lost, than can a dye liquor. In addition, because the whole purpose of a printing step is to force colours into fibres, there is often less need to wash out the excess colour, so leading to lower quantities of discarded pollutants.

7.8.2 Direct methods As in dyeing, there are several variants of printing methods, including block, roller, screen, resist, discharge, flock and transfer. In the first three of these, classed together as direct methods, the colouring agent is merely applied to the fabric surface and pressure (derived from a wooden block, a metal roller or a rubber squeegee, respectively) is used to force the dye paste into the body of the fabric for absorption by the fibres.

7.8.3 Resist printing In resist printing, a protective coating is first applied to the surface to prevent contact or attachment between the dye and the fabric in that region. The resist paste is applied in exactly the same manner as a printing paste, using chemical agents that block either the physical access of print paste to the fabric or the ability to form a chemical bond between fabric and colouring agent. Substances used (in addition to thickeners, which are needed to restrict movement away from the area that is to be prevented from becoming coloured, in the same way as direct methods) include paraffin and various resins. Each of these, but especially the latter, can be responsible for environmental risks (* W-3) after the excess is discarded. Once the resist paste is in place, the fabric is piece-dyed. The problems involved in the step exactly match those used in piece-dyeing itself.

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7.8.4 Discharge printing In discharge printing, the order of operation is essentially reversed. The fabric is piece-dyed initially, then a discharge agent (one that destroys the colour of the dyestuff) is applied to selected areas to create a pattern of a white zone on a coloured one. The latter two methods are both used as a means of obtaining a richer colour in the dyed areas, since piece-dyeing gives a much greater intensity of shade than does printing. From the environmental perspective, the processes combine the worst aspects of printing and dyeing, because the disadvantages of using paste are supplemented by those of piece-dyeing, and the need to add extra reagents in the form of the resist or discharge agents compounds the problem still further.

7.8.5 Flock printing Flock printing consists of the application of short dyed fibres to the surface of a fabric, either over the entire surface or in specific areas, with permanent attachment to the fabric being achieved by the use of a resin or other type of glue. Again, the ecological aspects of dyeing (of the fibres) have to be considered, in addition to those of the fixing agent when excess amounts are discarded to the environment (* W-3).

7.8.6 Heat-transfer printing Heat-transfer printing is an attempt to decrease pollution problems. It is most easily applied to polyester fabrics, using a dye-impregnated sheet of paper as an intermediate medium to contain the dye in readiness for application. The paper and fabric are placed in close contact, heat is applied to cause sublimation of the solid dye to a vapour phase, which is transferred across to the fabric as a result of the temperature gradient. The dyes (of acid or cationic class where dyeing of natural fibres is attempted and disperse dyes which are used to best advantage for synthetic fibres) provide a wide range of deep colours (thus preventing to some extent early discard of fabrics that have faded) and are able to attach themselves readily to the fibre molecules, with moderate to good permanence. The effect is to remove completely all need for liquids and printing pastes, omitting the washing, steaming or drying steps in conventional drying, so reducing the ecological harm. However, the need to make special paper and for a separate printing stage when applying dye to it, together with the disposal of the paper (* V-2), reduce considerably these advantages.

7.9

Drying and shipping

One further process needs to be considered, fabric drying. Again, it is not strictly a finishing treatment, but virtually all of the fabrics undergoing a finishing stage

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need to be dried at least once, and often more times, at some point in manufacture. The process is considered in Chapter 11, but is mentioned here because it is so important in finishing. The fabric has to be packed for shipment. This step, which is essential for protection from the elements, needs some form of outer coating, such as kraft paper or plastic, that has to be manufactured, with the usual environmental cost. In modern factories, it also involves the use of machinery, incorporating its costs. Finally, the matter of transportation should be considered. As before, this may be necessary during all parts of the production train, but the shipping of finished cloth is probably the largest single use of the operation. These then, are the harmful effects on the planet associated with the manufacture of textile fabrics. Unfortunately, the problem does not end here. After the finished articles are passed on to the consumer, there are still more costs incurred as a consequence of their use. These will be the subject of the next chapter.

References 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Arang, T. and Fernandez, J., Revista Quim. Textil, 1998, 139, 47–55. Korner, C., Melliand Textilber., 1999, 80(1–2), 73–76 and E 21–24. Xu, W., Cui, W., Li, W. and Guo, W., J. Soc. Dyers Colourists, 2001, 6, 352–355. Cheng, H., Yejuan, J. and Kai, S., J. Soc. Dyers Colourists, 2000, 7/8, 204–207. Geubtner, M. and Hannemann, K., Melliand Textilber., 2001, 7(September), 245–248. Lal, R.A., Colourage, 1998, 45(annual), 61–70. Soljacic, I., Katoric, D., Marija Granaric, A. et al., Int. J. Clothing Sci.Tech., 1998, 10(6), 98–101. Gulrajani, M.L., Asian Textile J., 1999, 8(2), 28–30. Mathew, M.R., Man-Made Textiles in India, 1999, 42(3), 97–101. Duschek, G., Melliand Textilber., 2001, 7(September), 240–244. Barton , J., Int. Dyer, 2001, 6, 11–12. Fung, W., Coated and Laminated Textiles, Cambridge, Woodhead, 2002. Bajaj, P., ‘Thermally sensitive materials’, in Tao, X. (ed), Smart Fibres, Fabrics and Clothing, Cambridge,Woodhead, 2001, p. 70. Kubin, I., Melliand Int., 2001, June, 134–138. Zyschka, R., Melliand Textilber., 2001, 7(September), 249. Min, R.R. and Huang, K.S., J. Soc. Dyer. Colourists, 1999, 155(2), 69–72. Rathi, D., Man-Made Textiles in India, 1999, 42(6), 231–234. Ramaswamy, G.N., Wang, J. and Socharto, B., Textile Chem. Colorist, 1999, 31(3), 27– 31. Saraf, N.M. and Alat, D.V., Colourage, 1998, 45(9), 27–34. Vukusiae, S.B., Katoviae, D. and Soljaeiae, I., 79th World Conference of Textile Institute, 10–13 Feb 1999, Chennai, India, Vol 2, pp. 51–59. Scott, I., World Sports Activewear, 1998, 4(4), 24–25. Anon., Textiles Mag., 1998, 27(4), 4. Vohrer, U., Asian Textile J., 1998, 7/8, 93–96. Benisek, L., Textile Horizons, 1999, 19(1), 24–25. Anon., Colourage, 1998, 45(12), 47–49.

Fabric treatment processes 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

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Bhattacharyya, N. and Acharekar, S., Br. Textile Res. Assoc. Scan, 1998, 29(2), 18–25. Anon., Knitting Tech., 1998, 20/4, 170–171. Achwal, W.B., Colourage, 1998, 45(1), 45–46. Doraisamy, I. and Janakiraman, K.P., 79th World Conference of Textile Institute, 10–13 Feb 1999, Chennai, India, Vol 2, pp. 29–32. Anon., Int. Dyer, 1999, 184(5), 28–30. Wakida, T., Cho, S., Choi, S. et al., Textile Res. J., 1998, 68, 848–853. Anon., Textile Dyer and Printer, 1998, 31(21), 17. Ganssauge, D. and Thomas, H., DWI Rep., 1999, 122, 451–455. Morse, V., Thomas, H. and Hocker, H., DWI Rep., 1999, 122, 514–519. Parton, K., Int. Dyer, 1999, 184(4), 14–17. Shukla, S.R., Colourage, 1998, 45(annual), 175–186. Lennox-Kerr, P., Int. Dyer, 2000, 5, 29. Kawahara, Y., Kikutani, T., Sugiura, K. and Ogawa, S., J. Soc. Dyers Colourists, 2001, 5, 266–269. Özdogan, E., Saber, R., Ayhan, H. and Seventikin, N., J. Soc. Dyers Colourists, 2002, 3, 100–103. Galgali, M.R., Colourage, 1998, 45(7), 20–22. Zacharia J., Br. Textile Res. Assoc. Scan, 1998, 29(3), 1–2.

8 Use of textiles

8.1

Primary and secondary production

Once a textile fabric has been manufactured, its potential for causing damage to the environment does not end. A fabric, no matter how high its quality or how well it is finished, coloured and generally enhanced, is of little or no use unless it is made into something. The possible products of this further processing include such widespread objects as clothing, upholstery, drapery, bedding and industrial goods. We normally tend to regard the primary (i.e. fabric production) and secondary (i.e. products made from fabrics) textile industries as separate ones, but the environment makes no such distinction; pollution is pollution no matter what its source may be. One of the major problems facing the entire industry today is a lack of communication between these two different areas, since there is often a misinterpretation of the needs of the secondary sector by members of the first one, as well as a misunderstanding of the capabilities of the primary industry by the secondary one. Nature may benefit substantially by the development of a closer connection between the two, reducing the number of discarded materials that result from these failures to match needs, abilities and production.

8.2

Types of use

In view of the nature of this book, a distinction is proposed here between different types of use in a way not normally adopted. Those uses intended to protect the environment in some way will be separated from the others and treated in Chapter 13. This is obviously not a simple matter, because there will be immense grey areas where the two cannot readily be distinguished. A geotextile barrier designed to prevent flooding of houses in an area inundated with water from a burst river bank, for instance, is clearly intended to keep the human inhabitants of the threatened region safe and alive. A geotextile used to contain polluted substances in a landfill site from leaching out into the water table is intended to protect the environment. Yet, the flood barrier also prevents erosion of land by water flow, while the 90

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contained pollution is also prevented from poisoning human beings, so that both end results are met in each case. The distinction here (which is totally arbitrary and personal) is to determine what seems to be the more important criterion for use and to allocate the application to the section that makes most sense in that case. In this chapter, the ‘normal’ uses will be dealt with and the ‘environmental protection’ uses will be deferred to Chapter 9.

8.3

Normal uses

8.3.1 Clothing The most obvious normal use of textiles is in making clothing, a use that has been around for thousands of years. For the purpose of this chapter, products of the garment sector will include only clothing and accessories. As always, the machines needed to make them are complex, though usually much smaller in scale than those used in textile yarn and fabric manufacture. Cutting, sewing, pressing and other machines all need to be made and operated, at the now-familiar cost to the planet. There are frequently excess pieces of fabric that are cut away in making clothing to be discarded. It is, admittedly, possible to recycle these scraps, as will be discussed in the next chapter, but large, complex machinery is needed to put them back into the production train. Although such scraps may be too small anyway to make recycling worthwhile, one author1 describes yarns made with fibres recovered from the garment industry, noting that they avoid excess pollution by eliminating the need for fertilisers and dyes. Uses as socks, blankets and upholstery materials are mentioned specifically, a point that gives the key to this over-optimistic attitude. These articles differ from most textile end uses in that colour is not critical, unlike virtually all other applications. In more usual recycled goods, especially as they are almost invariably coloured, some process for removing all the dyestuffs is always needed. This involves chemical reactions in which bleaching agents or dye strippers are used to destroy the dye molecules or change their molecular structure to render them colourless. These substances are waste products that can harm the Earth once discarded into the environment (* L-2, W-3) (see Table 1.1 for an explanation of codes).

8.3.2 The fashion industry One of the most powerful driving forces influencing the manufacture of clothing is the fashion industry, which has increased considerably in importance in the centuries since the Industrial Revolution. Clothing is one of the easiest ways to display wealth conspicuously, so it is now accepted among people in many parts of the world (and particularly in the developed nations) that new outfits should be purchased at every season of the year. Seasonal variations in climate are an added major incentive for these expenditures and, in practice, the resulting annual

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production of clothing may be regarded as too great to be justified as environmentally responsible. Few people actually wear more than one outfit at a time, which means that many garments are stored in environmentally destructive plastic bags for a great proportion of their useful life. After the season ends, it is currently fashionable, in a kind of lip service to planetary well-being, to ‘recycle’ the articles via alternative outlets, such as second-hand clothing stores or factory shops selling designer clothes at reduced prices. Even this gesture is not entirely altruistic in terms of the Earth’s welfare; the loss of an article of clothing invariably leaves a gap that must be filled by something new in the wardrobe of the person making this supreme sacrifice. The premises where the unwanted garments are resold also need to be built, heated, lit, staffed and so on. Unfortunately, the pressures of the fashion industry appear to be increasing rather than declining, as would be preferable for ecological welfare. The problem, as always, lies in commercial interest. Modern people, especially in the developed world, are accustomed to the need to follow a fashion cycle on an annual or even seasonal basis, so that the fashion industry (and those connected with it) has a vested interest in ensuring a regular turnover of garments. It is inevitable that a large reduction in sales would lead to a major loss in employment, because it is not only the textile and clothing manufacturers who would be out of work, but also the designers, alteration staff, marketing specialists, transportation personnel, retailers, magazine editors or artists, and anyone else with an ancillary interest in the fashion world. The cumulative psychological effect on Society of the need of all these people to be kept in employment is difficult to resist, meaning that the relentless drive to be up-to-date will continue for as long as we (or our planetary home) are prepared to tolerate it.

8.4

Environmental aspects

8.4.1 Laundering The renewal of the fashion requirement per se does not merely cause environmental problems in the debate regarding recycling versus disposal. As a consequence of our modern lifestyle and technology, dust and dirt are omnipresent, and soiling necessitates emergency procedures in the form of laundering or dry cleaning. Both of these can cause environmental difficulties. Laundering involves exposing the textile article to the combined effects of water, heat, agitation and detergent. Often, an optical bleach or a fabric softener is added to the mix, and machine drying is frequently used. Both of these procedures give a much more luxurious feel than do an untreated wash and outdoor drying on a clothing line. The energy needed to heat the water and operate the machinery, together with the chemicals (* W-3) discarded into the drain, are a source of harm, as also are the heat needed to operate and the polluted exhaust emitted (* A-2) from the dryer. The thermal load from both washing and drying can also affect the surrounding air or water (* W-1), making

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it unsafe for other species to exist in the neighbourhood of the discard point unless precautions are taken to reduce the rise in temperature occurring on discharge.

8.4.2 Dry cleaning Dry cleaning also has ecological consequences. The machinery needs to be built and operated, while the solvents used for extracting the dirt are often toxic or carcinogenic. Even though strenuous efforts are made to contain them and recycle them for later use, there is still an inevitable loss (* A-2) because of entrapment in the fibres or escape into the air via the garment transport path. Jipp2 describes nontoxic stain removal using solvents without chlorocarbons, so that the chemicals can be regarded as being kind to both fibre and environment. Nevertheless, all of the reagents used in maintenance, even these more harmless ones, have to be manufactured, with expensive loading on the environment.

8.4.3 Maintenance chemicals The actual chemical substances used in maintenance can be examined in more detail to ascertain their potential for harm. As a consequence of our current fascination for cleanliness, garments are washed or cleaned far more often than is necessary for the sake of health or even hygiene. For this reason, the quantities of detergent, softeners, bleaching agents, dry cleaning solvents or other chemicals expelled are enormous. Detergents contain alkalis and organic chemicals that act as pollutants (* W-3). They also often contain phosphates, used as ‘builders’ to enhance the effectiveness of the washing action, which are known to encourage the growth of algae in large bodies of water. These can take over the oxygen available in the water, preventing other species (both animal and vegetable) from having access to it, As a result, fish can die and the balance of the local aquatic plants can be disturbed seriously, bringing about major changes in the locality and eventually resulting in a dead body of water where fish no longer exist and weeds choke the entire surface. Fabric softeners, usually quaternary ammonium compounds, are becoming more and more popular. These bring about water pollution (* W-3). They are produced by relatively complex chemical reactions, with the usual environmental concerns and their disposal brings about harmful changes in the local water supply.

8.5

Household textiles

In the home, textiles find widespread use, from household furnishings such as carpets, cushions and table linens, to towels, bath mats or dish cloths. David Rigby Associates3 give an overview of the various types of textile applications in home furnishing products, suggesting that the largest growth in the foreseeable future will occur in non-wovens or fibrefill categories, rather than in the more traditional

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woven or knitted fabrics. Two unusual applications in the household category have been reported in the literature; one author4 writes of the usefulness of wool tightly woven and attached to gypsum board (in the form of decorative panels) as a means of combating the relatively new hazard of sick building syndrome by absorbing the formaldehyde reputedly responsible for this problem. The second application5 consists of a system used to wrap houses during construction to maintain acceptable working comfort, for craftsmen operating on the outside walls of the house in adverse weather conditions, with enough moisture vapour permeability to ensure that breathing comfort can be retained.

8.6

Industrial and medical uses

8.6.1 Technical textiles Bhonde6 gives an overview of textiles used in applications beyond those of clothing or household purposes, while Legler7 examines technical textiles from the perspective of recent advances. Both authors more or less agree on the list of end uses, including geotextiles, agrotextiles, industrial products (including composite reinforcement), automotive, space, protective and medical ones. Not mentioned specifically in this list is the use of textiles in building, which may be extended to the subject of architectural fabrics. Their adoption, according to Hill,8 reduces building time significantly and saves natural resources (a valuable advantage from our point of view!), while providing long life and cost-effective, aesthetically pleasing appearance. Swedberg9 describes applications of tent structures using PTFE-coated fibreglass with steel tubing and cables and, in a later paper,10 the use of air-inflated beams for supporting massive structures in high wind or loading conditions with potential applications in aerospace or nautical projects. Other interesting applications are the use of a composite of high-tensile glass with epoxy resin to make a reinforcement beam as protection against earthquake collapse11 and wrapping corroded bridge columns with carbon fibre12 to prevent further damage.

8.6.2 House construction House construction can also be aided indirectly by fibres, when used as reinforcement for concrete or in other aspects of building. In such applications, the environment is preserved by preventing premature failure of the material, allowing it to last longer. Peter13 recommends Kevlar for concrete reinforcement, because it imparts low density, non-catastrophic failure (and resistance to repeated impacts) to the concrete. In addition, because the fibres are electrically insulating, Kevlar permits building to take place more safely near high-voltage power lines. Komatsu et al.14 assess the durability of geotextiles in reinforcing asphalt concrete, noting that this process increases viscosity of the material and reduces the stress

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concentration of wheel loading. Locatelli15 reports the production of a stretchable roofing felt that can be installed and maintained without shrinkage when used in a layered system. A French company16 is marketing a woven structure that can be laid across soft, sandy or swampy ground, allowing vehicles to pass safely. In temporary houses, such as tents, fabrics are invariably used for their combination of light weight, easy folding ability, weather (especially wind) resistance and versatility.

8.6.3 Motor vehicles Fung17 provides a detailed description of the many applications of textiles, in the form of coated or laminated fabrics, in vehicles. He includes in his listing seat materials, headliner structures, other interior coverings, air bag components, convertible coverings, liners for bonnets or wheel arches, carpeting, noise control items and drive belts. In view of current traffic hazard concerns involving motor vehicles, the air bags used to enhance safety in crashes have received particular attention. One writer18 recommends the use of nylon 4.6 in making them, because of its better thermal stability. Barnes and Rawson,19 after devising a new test to assess the efficiency of coated fabrics for this end-use, find that nylon 6.6 is better than either nylon 6 or polyester in this regard. They also report that a silicone-based coating should be applied to the fabric to increase thermal resistance still further. Gutlein et al.20 recommend a polyurethane bladder in a textile net for making sideimpact bags, while yet another author21 would like to see needle-punched construction methods used to increase permeability in a controlled manner and describes conditions for achieving optimum gas transfer characteristics.

8.6.4 Medical textiles Medical uses of textiles should also not be ignored, as they constitute a major area of advance for the industry. They are summarised in Section 6 of the Appendix, where more information regarding applications (such as in surgical uses of clothing and inserts into the body, or general medical clothing and health care) can be found.

8.6.5 Industrial applications The widespread use of textiles in industrial applications, however, is not generally discussed in any detail. Various authors17, 22 write articles dealing with the many valuable attributes of technical fabrics, including those intended for space activity, automotive filtration, airbags, composites, marine uses, laminating, seismic protection and resistance to harmful agents. Applications range widely in type and some consideration of representatives of all the varieties of application should be

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included. They may be divided into those used directly by industry, those used in leisure or sport activities and those in which heavy duty use is needed in everyday life. Textiles used directly in industry include such diverse items as tarpaulins, filters, acoustic or thermal insulation and protective garments for workers.

8.6.6 Other uses Three specific types of more interesting use can be identified. First, transport via heavy lorries is rendered less perilous (and has a lower risk of polluting the road or causing accidents by losing part of the material being shipped) by the use of a new kind of tarpaulin,23 knitted from stretchable textured polyester, that conforms to the shape of a load, reducing flapping as the vehicle moves. Second, filters appear to be popular subjects for research, an occurrence caused at least in part by the need for a cleaner environment. Third, leisure or sport applications are rapidly increasing and include items such as tentage, sleeping bags, boat sails, mooring ropes or other marine cordage, aircraft skins, parachute fabrics, climbing ropes, bungee cords, balloon fabrics or guy ropes. Little attention appears to have been paid to most of these applications, although there are some papers worth mentioning in the literature. The work taking place in each of these areas is summarised in Sections 7 and 8 of the Appendix. Finally, one or two less obvious uses may be mentioned. Newberry24 reviews new developments in the use of composites in corrosion-resistant applications such as piping, lamp poles, and tanks to contain hot brine or for use in deionised brine service. Risks of harm from mobile phones, reportedly causing brain damage from electromagnetic radiation, are supposedly counteracted25 by the use of a flexible metal-coated fibre, preferably an acrylic one coated with copper or nickel. Plates used to press boards of plywood, or those for printed circuits, lined with textile cushions designed for high-temperature use, are reported,26 while Marsh27 discusses the use of fibre-reinforced plastics for improving under-sea oil extraction; the smooth surface, chemically inert nature and low weight mean that lower losses from corrosion and oil escape will occur, so providing an ecological benefit. Kotliar28 uses textile and carpet waste to produce a low-cost, wood-like material by incorporating them in a high-modulus phenol/formaldehyde matrix. Other heavy-duty uses in everyday life include tyre cords, seat belt webbing, vehicle upholstery, carpeting, wall hangings, conveyor belts, drive belts, tow ropes, isolation suits, protective clothing, space suits, architectural fabrics and geotextiles. In addition, cleaning cloths, surgical clothing or drapes, bandages or other dressings should also be added to the list. Many of these will be dealt with later in the book but, as a final general comment here, we should note that all of them, in common with all the cases mentioned above, have a production process that tends to be an expensive one from the environmental perspective and, in many cases, create difficulties in disposal.

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References 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Anon., Amer.Textile Int., 1998, 27(8), 84. Jipp, M., Bekleidung Wear, 1998, 50(20), 48–49. David Rigby Associates, Textile Horizons, 1999, 19(1), 12–15. Anon., Wool Record, 1999, 158/3657, 20. Bay Mills Ltd., High Perf. Textiles, 1999, August, 6–7. Bhonde, H.U., Synthetic Fibres, 1999, 29(1), 17–19. Legler, F., Textile Horizons, 1998, 18(5), 10–13. Hill, D., Tech. Textiles Int. 1998, 7(6), 17–23. Swedberg, J., Ind. Fabric. Product Rev., 1998, 75(4), 16–18. Swedberg, J., Ind. Fabric. Product Rev., 1998, 75(4), 52–55. Hexcel-Fyfe Co., High Perf. Textiles, 1999, June, 6–7. Ma, G., Adv. Comp. Bull., 1998, December, 1–12. Peter, E., High. Perf. Textiles, 1999, August, 5. Komatsu, T.et al., Geot. Geom., 1998, 16(5), 257–271. Locatelli, A., High. Perf. Textiles, 1999, August, 6. Societé à Responsabilité Limitéé Deschamps, High. Perf. Textiles, 1999, July, 7–8. Fung, W., Coated and Laminated Textiles, Cambridge, Woodhead, 2002. Anon., High Perf. Textiles, 1998, December, 4–5. Barnes, J.A. and Rawson, N.J., Textiles Asia, 1998, 29(11), 37–40. Gutlein, U., Schaper, J. and Von Dreyse, J.S., Textiles Usages Techniques, 1998, 29, 62– 64. Anon., High Perf. Textiles, 1999, January, 6–7. Various authors, Textile Month, 2000, March, 6–22. Wagner, J.E., High. Perf. Textiles, 1999, August, 7–8. Newberry, A.L., Reinforced Plastics, 1998, 42(8), 34–38. Daiwabo Co. Ltd., High. Perf. Textiles, 1998, October, 4. Du Pont Taiwan Ltd., High. Perf. Textiles, 1998, September, 5–6. Marsh, G., Reinforced Plastics, 1998, 42(11), 32–36. Kotliar, A.M., Polymer Plastics Tech. Eng., 1999, 38(3), 513–531.

9 Environmental protection

Now that we have examined the way in which textile production and use can harm our planet, it is time to look at the steps we are taking as a society to minimise that harm. In this chapter, we will look at the ways in which governments attempt to compensate for the damage caused within their jurisdiction, how successful they are and how we can evaluate their success (or lack of success) in stopping environmental damage. We should not forget that other industries, besides the textile one, are guilty of causing the same pressures on planetary health, but this book must concentrate on how textile manufacturers and ourselves, as textile consumers, should be judged. In particular, what steps are being taken by the industry to minimise the onslaught that textile production makes on the health of the planet and how effective are these steps?

9.1

Commitment

The most critical point is a distinct lack of commitment on the part of many governments to do anything but pay lip service to the environmental lobby. There are plenty of examples to support this admittedly pessimistic viewpoint. The most recent one, at the time of writing, is the refusal of the USA to ratify the Kyoto Accord, on the grounds that it is likely to be ineffective. It seems to the author that any move towards restricting toxic emissions, even if ineffective, is better than agreeing to permit virtually unlimited pollution by industry to continue unabated, presumably because curbing the polluting activities would be economically harmful. The Earth Summit in Rio de Janeiro in 1992, too, is looking more and more like a waste of time as the years pass by without any tangible action on its recommendations. The ready availability of weapons of destruction to both sides in a war, as long as there is money to pay for them, also appears to reflect a somewhat cynical attitude to preserving our planet unharmed. So does the willingness to ship oil to every part of the globe without much long-term concern whether a tanker is wrecked and spews its polluting cargo over pristine beaches. Environmentalists are regarded as antisocial creatures determined on a course of action intended to wreck the economy, rather than as conscientious citizens trying to save their 98

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planet. The time has surely come for governments to be more responsible in investing for the future welfare of the Earth, rather than in trying to maintain high living standards for a favoured few citizens.

9.2

Protective applications

There are many published references in the area of environmental protection in the textile context, including some general ones dealing with the need for the industry to attack pollution problems. Germany establishes regulations1 to limit or eliminate environmental and health hazards for textile and leather processing industries. Japanese textile firms2 emphasise harmony with the environment, mentioning, for example, the possibility (well known for many years in the West) of recycling used clothing. They also introduce industrial consumers to the ideas of producing environmentally friendly products, saving energy and reducing water pollution. Orzada3 carries out a survey to discover the degree of development of environmental responsibility regarding products and processes in the USA apparel industry, looking at types of environmentally friendly products, environmental policies, fabric waste disposal and reduced packaging waste. Cunho et al.4 carry out research relevant to environmental aspects of textile materials, such as the impact of some environmental parameters on fibre properties and the evaluation of products on the basis of their environmental safety. Muirhead5 considers the development of environmental awareness, touching on emission controls, water charges, landfill tax and packaging regulations as opportunities to increase profits and reduce costs.

9.2.1 Ecologically benefi