The Application of Textiles in Rubber David B. Wootton Rapra Technology Limited Shawbury, Shrewsbury, Shropshire SY4 4NR, United Kingdom Telephone: +44 (0)1939 250383 Fax: +44 (0)1939 251118 http://www.rapra.net Textiles Title Page etc. 31/7/01, 11:34 am1 First Published in 2001 by Rapra Technology Limited Shawbury, Shrewsbury, Shropshire, SY4 4NR, UK ©2001, Rapra Technology Limited The right of David Wootton to be recognised as the author of this work has been asserted by him in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act 1998. All rights reserved. Except as permitted under current legislation no part of this publication may be photocopied, reproduced or distributed in any form or by any means or stored in a database or retrieval system, without the prior permission from the copyright holder. A catalogue record for this book is available from the British Library. Typeset by Rapra Technology Limited Printed and bound by Polestar Scientifica, Exeter, UK ISBN: 1-85957-277-4 Textiles Title Page etc. 31/7/01, 11:34 am2 1 Preface Rubber and textiles have been used together, each working with the other to give improved performance in a very wide range of applications, since the earliest days of the rubber industry in the more developed areas of the world. For many years, rubber companies of reasonable size, using textile reinforcement, would employ their own textile technologist working alongside the rubber technologists. Over the last third of the twentieth century, faced with global competition and the need to control and reduce total costs, this luxury has largely disappeared apart from the largest companies (particularly the tyre companies). Most organisations now rely on their textile suppliers to provide technical knowledge and expertise. As a result, the textile component for many applications is now considered in much the same way as the other raw materials, that is as an existing product, which only requires introducing into the manufacturing process, without any special knowledge or understanding, and is supplied against an agreed specification, which was probably drawn up by the textile manufacturer anyway. The aim of this current work is to provide a general background to and a basic awareness of the technology of textiles, to give the rubber technologists an improved understanding of the uses, processes and potential problems associated with the use of textiles in rubber products. The most important and by far the largest use of textiles in rubber is in the tyre industry. This area is not covered in this book, as the field covers such a wide range that it would require a volume on its own. In addition, most tyre companies have their own textile specialists and have developed their own technologies, shrouded in the mysteries of ‘trade secrets’. The first part of this volume covers the basic technology of the textile fibres and the processes used in preparing these ‘ready made’ raw materials for rubber reinforcement. Particular attention is given to various aspects of adhesion, adhesive treatments, the effects of rubber compounding and processing and the assessment of adhesion. In the second half of the book, the major applications of textiles in rubber are described; the aim here is to illustrate the way that the textile component can be designed and engineered to obtain the optimum reinforcement and performance for each particular application. These descriptions are not intended to be definitive technological theses on Preface 31/7/01, 11:34 am1 The Application of Textiles in Rubber 2 the different applications. However, they indicate the balance of properties required and how these can be obtained in the textile component by selection of the fibres used, the physical form of the reinforcement and the processes and treatments required. Over the years since the earliest days of Hancock, Goodyear and Macintosh, there have been many significant breakthroughs and developments, in both textile and rubber technologies. Originally, there were only cotton and natural rubber, now there are wide ranges of both synthetic rubbers and of man-made fibres. There have been great advances in the technologies of vulcanisation and of adhesive treatments; the service requirements have become more stringent and operating conditions more severe, but these issues have largely been overcome by improving expertise and knowledge. However, over the last two decades, there has been relatively little advance in the general technologies of textiles or rubbers; most developments have been targeted either at cost containment or at very high performance (and consequently very high cost) applications, particularly aerospace, with only minor spin-offs for everyday terrestrial applications. Where possible, the general content of the chapters has been kept as simple and practical as possible but where there is a more theoretical discussion of certain aspects, these have been separated into appendices, at the end of the relevant chapters. The general discussion can thus be read without the intrusion of the more theoretical aspects, but these are still available, if desired. A glossary of terms has been included to assist the reader. I wish to thank all those at Rapra who have encouraged and assisted me in the preparation and publication of this book, in particular Clair Griffiths and Steve Barnfield, for their work in preparing the manuscript for publication. David B. Wootton Preface 31/7/01, 11:34 am2 i Contents Preface 1 1 Historical Background 3 Introduction 3 1.1 The Textile Industry 3 1.2 The Rubber Industry 6 1.3 Textile and Rubber Composites 10 References 13 2 Production and Properties of Textile Yarns 15 Introduction 15 2.1 Production Methods for Textile Fibres 15 2.1.1 Cotton 15 2.1.2 Rayon 21 2.1.3 Nylon 24 2.1.4 Polyester 26 2.1.5 Aramid 28 2.2 General Characteristics of Textile Fibres 30 2.2.1 Cotton 30 2.2.2 Rayon 32 2.2.3 Nylon 33 2.2.4 Polyester 34 2.2.5 Aramid 35 2.3 General Physical Properties of Textile Fibres 36 2.3.1 Cotton 36 Textiles Contents 31/7/01, 11:34 am1 The Application of Textiles in Rubber ii 2.3.2 Rayon 38 2.3.3 Nylon 39 2.3.4 Polyester 40 2.3.5 Aramid 40 References 40 3 Yarn and Cord Processes 41 Introduction 41 3.1 Yarn Preparation Methods 41 3.1.1 Twisting 42 3.1.2 Texturing 49 3.2 Warp Preparation 52 3.2.1 Direct Warping 53 3.2.2 Sectional Warping 54 3.3 Sizing 57 4 Fabric Formation and Design of Fabrics 59 Introduction 59 4.1 Fabric Formation 59 4.1.1 Weaving 59 4.1.2 Knitting 64 4.1.3 Non-Woven Fabrics 68 4.2 The Design of Woven Fabrics 70 4.2.1 Physical Property Requirements 70 4.2.2 Selection of Fibre Type 71 4.2.3 Selection of Fabric Construction 74 5 Heat-Setting and Adhesive Treatments 83 Introduction 83 5.1 Heat-Setting Machinery 83 Textiles Contents 31/7/01, 11:34 am2 iii Contents 5.2 Heat-Setting 90 5.3 Adhesive Treatment 94 5.3.1 Cotton 94 5.3.2 Rayon 95 5.3.3 Nylon 98 5.3.4 Polyester 99 5.3.5 Aramid 101 5.4 The In Situ Bonding System 102 5.5 Mechanisms of Adhesion 103 5.6 Environmental Factors Affecting Adhesion 107 Appendix V Interfacial Compatibility 109 References 112 6 Basic Rubber Compounding and Composite Assembly 113 6.1 Compounding 113 6.1.1 Polymers 113 6.1.2 Curing Systems 114 6.1.3 Fillers 116 6.1.4 Antidegradants 117 6.1.5 Other Compounding Ingredients 117 6.2 Processing 117 6.3 Composite Assembly 118 6.3.1 Calendering 118 6.3.2 Coating 124 References 127 7 Assessment of Adhesion 129 Introduction 129 7.1 Cord Tests 129 Textiles Contents 31/7/01, 11:34 am3 The Application of Textiles in Rubber iv 7.1.1 Pull-Out Tests 130 7.1.2 Cord Peel Test 130 7.2 Fabric Test Methods 133 7.3 Testing and Interpretation of Results 138 7.4 Adhesion Tests for Lightweight Fabrics and Coatings 140 7.5 Peeling by Dead-Weight Loading 142 7.6 Direct Tension Testing of Adhesion 143 7.7 Adhesion and Fatigue Testing 145 7.8 Assessment of Penetration into the Textile Structure 146 Appendix VII: The Physics of Peeling 148 References 153 8 Conveyor Belting 155 Introduction 155 8.1 Belt Construction and Operation 160 8.1.1 Carcase 160 8.1.2 Insulation 161 8.1.3 Covers 162 8.2 Belt Design 165 8.2.1 Plied Belting 167 8.2.2 Single-Ply and Solid-Woven Belting 171 8.2.3 Steel Cord Belting 172 8.3 Belting Manufacture 172 8.3.1 Belt Building 173 8.3.2 Pressing and Curing 173 8.3.3 Belt Joining 178 8.4 Belt Testing 182 8.4.1 Tensile Strength and Elongation 182 Textiles Contents 31/7/01, 11:34 am4 v Contents 8.4.2 Gauge 183 8.4.3 Adhesion 183 8.4.4 Abrasion 183 8.4.5 Troughability 183 8.4.6 Fire Resistance 183 References 184 9 Hose 187 Introduction 187 9.1 Hose Manufacture 188 9.1.1 Braiding 188 9.1.2 Spiralling 190 9.1.3 Wrapped Hose 191 9.1.4 Knitted Hose 192 9.1.5 Oil Suction and Discharge Hose 192 9.1.6 Circular Woven Hose 193 Appendix IX 195 i. Neutral Angle 195 ii. Bursting Pressure 196 10 Power Transmission Belts 199 Introduction 199 10.1 Main Types of Power Transmission Belts 200 10.1.1 V-Belts 200 10.1.2 Timing Belts 203 10.1.3 Flat Belting 203 10.1.4 Cut-Length Belting 205 10.2 Manufacture of Power Transmission Belting 206 10.2.1 Manufacture of V-Belts 206 10.2.2 Manufacture of Timing Belts 209 Textiles Contents 31/7/01, 11:34 am5 The Application of Textiles in Rubber vi 10.3 Effect of the Textile Reinforcement on Belt Performance 209 References 212 11 Applications of Coated Fabrics 213 Introduction 213 11.1 Inflatable Structures 214 11.1.1 Inflatable Boats 214 11.1.2 Oil Booms 218 11.1.3 Inflatable Dams 219 11.1.4 Inflatable Buildings 220 11.1.5 Dunnage Bags 221 11.2 Non-Inflated Structures 222 11.2.1 Reservoir and Pond Liners 222 11.2.2 Flexible Storage Tanks 223 11.2.3 Supported Building Structures 223 References 224 12 Miscellaneous Applications of Textiles in Rubber 225 Introduction 225 12.1 Hovercraft Skirts 225 12.1.1 Types of Skirt 226 12.2 Air Brake Chamber Diaphragms 229 12.3 Snowmobile Tracks 230 References 231 Abbreviations and Acronyms 233 Glossary 234 Index 239 Textiles Contents 31/7/01, 11:34 am6 [...]... The Application of Textiles in Rubber ‘factory’ at Winchester, for the production, on a larger scale, of warm woollen blankets, to help reduce the impact of the British weather on the soldiers from southern Europe In the family context, it generally fell to the female side to undertake the spinning, while the weaving was the domain of the men Spinning was originally done using the distaff to hold the. .. performing all the other stages of weaving manually (see Chapter 4 for a description of the weaving process) In 1733, John Kay invented the ‘flying shuttle’, which enabled a much faster method for inserting the weft into the fabric at the loom and greatly increased the productivity of the weavers Until the advent of the flying shuttle, the limiting factor in the production chain for fabrics was the output... rayon, for the reinforcing plies of fabric But this introduced another problem This was the first major use of fibres other than cotton Up to now there had been no problem in adhering the rubber to the textile inserts: the techniques of spreading or frictioning had resulted in good mechanical adhesion, due to the embedding of the fibre ends of the staple yarns into the rubber With the continuous filament... to the discovery of polyester in 1941, and over the ensuing decades, polyolefin fibres (although because of their low melting/softening temperatures, these are not used as reinforcing fibres in rubbers) and aramids As the chemical industry greatly increased the types of yarns available for textile applications, so the machinery used in the industry was being developed Whereas the basic principles of. .. wound into large cans, in this final stage, the sliver is wound onto a supporting tube, for presentation to the spinning frame (5) Spinning: in the final spinning stage, the sliver is reduced still further in size and the required level of twist is inserted In selecting the twist to be used there are various factors to be considered The higher the twist level, the more firmly held together are the individual... than on the ring system, but some of the longer protruding fibre ends are picked up by the rotor wall and wrapped round the bundle of fibres, thus binding them together into a coherent yarn With the rotor system, the bulk of the fibres are not compressed together to the same extent as on ring spinning with the higher level of twist, and so a bulkier yarn is obtained The binding together of the fibres... twist is inserted into the yarn At the same time, of course, the yarn is being fed forward and wound up onto the tube on the spindle; by adjustment of the rate at which the yarn is fed forward and the speed of rotation of the spindle, so the level of twist inserted into the yarn can be controlled 19 Chapter 2 19 31/7/01, 11:34 am The Application of Textiles in Rubber Figure 2.2 Disignation of twist... these developments in spinning, similar changes were taking place in the weaving field, with the invention of the power loom by Edmund Cartwright, in 1785 With this increase in mechanisation of the whole industry, it was logical to bring the production together, rather than keeping it widely spread throughout the homes of the producers Accordingly, factories were established The first of such was in. .. direction of the twist of the yarn, when held vertically The fibres either slope from top left to bottom right, as in the central bar of the S or in the opposite direction as in the central bar of the Z; this is illustrated in Figure 2.2 A schematic representation of a ring spinning spindle is given in Figure 2.3 The sliver from the drafting frame is fed between three pairs of drafting rollers, to reduce the. .. clothing These are moving more slowly than the cylinder, 17 Chapter 2 17 31/7/01, 11:34 am The Application of Textiles in Rubber Flats ROVING OUT Comb LAP IN Feed nip Takerin Doffer Main cylinder (a) CARD CLOTHING (b) CARDING ACTIONS Position Motion Action Wires (i) stripping (ii) Textile/ rubber backing carding Figure 2.1 Cotton carding but in the same direction and with the wires angled in the opposite . domain of the men. Spinning was originally done using the distaff to hold the unspun fibres, which were then teased out using the fingers and twisted into the final yarn on the spindle. In the 1530s,. understanding of the uses, processes and potential problems associated with the use of textiles in rubber products. The most important and by far the largest use of textiles in rubber is in the tyre industry. This. reduce the impact of the British weather on the soldiers from southern Europe. In the family context, it generally fell to the female side to undertake the spinning, while the weaving was the domain