Contents
Contributor contact details ix
Woodhead Publishing Series in Textiles xi
Preface xvii
Part I Fundamental principles of nonwovens
1 The formation of dry, wet, spunlaid and other types of nonwovens 3
A. WILSON, Nonwovens Report International, UK
1.1 Introduction 3
1.2 Formation of drylaid nonwovens 5
1.3 Wetlaid nonwovens 6
1.4 Formation of spunlaid nonwovens 8
1.5 Meltblowing of nonwoven fabrics 9
1.6 Formation of web bonding techniques 11
1.7 Formation of nanofibre nonwovens 11
1.8 Bibliography 16
2 The influence of fiber and fabric properties on nonwoven performance 18
P. P. TSAI, The University of Tennessee, USA; and Y. YAN,
South China University of Technology, P. R. China
2.1 Background 18
2.2 Influence of solidity or packing density (á), and porosity (å) on nonwoven performance 20
2.3 Experimentally calculated pore size of nonwovens 21
2.4 Pore size distribution 24
2.5 Experimentally calculated fiber size of nonwovens 27
2.6 Theoretically calculated pore size, air permeability, pressure drop and filtration efficiency 31
2.7 Influence of thermal insulating properties on nonwoven performance 33
2.8 Influence of filtration efficiency (FE) on nonwoven performance 37
2.9 Influence of mechanical properties on nonwoven performance 40
2.10 Computer programs for measuring nonwoven performance 42
2.11 References 44
3 Biodegradable materials for nonwovens 46
G. BHAT, The University of Tennessee, USA; and D. V. PARIKH,
Southern Regional Research Center, USDA, USA
3.1 Introduction 46
3.2 Reasons for using biodegradable nonwovens 47
3.3 Cotton, hemp and other natural fibres 48
3.4 Cotton and flax-based nonwovens 50
3.5 Nonwovens from animal fibres 54
3.6 Technologies for biodegradable nonwovens 56
3.7 Applications of biodegradable nonwovens 58
3.8 Sources of further information and advice 60
3.9 References 61
Part II Nonwoven applications
4 Flame retardant nonwovens 65
S. DUQUESNE and S. BOURBIGOT, Ecole Nationale Supérieure
de Chimie de Lille (ENSCL), France
4.1 Introduction 65
4.2 Basics of flame retardancy 67
4.3 Different approaches for flame retardant nonwovens 69
4.4 Applications of flame retardant nonwovens 79
4.5 Conclusion and future trends 82
4.6 References 82
5 Nonwoven personal hygiene materials and products 85
J. R. AJMERI and C. J. AJMERI, Sarvajanik College of Engineering and
Technology, India
5.1 Introduction 85
5.2 Types of nonwoven materials used for hygiene products 87
5.3 Properties of nonwoven hygiene materials 89
5.4 Applications of nonwoven hygiene materials 90
5.5 Future trends 96
5.6 Sources of further information and advice 97
5.7 References 97
6 Nonwovens for consumer and industrial wipes 103
D. ZHANG, Textile Research Associates, USA
6.1 Introduction 103
6.2 Key drivers and trends 104
6.3 Nonwoven wipes technology 108
6.4 End-user applications of nonwoven wipes 110
6.5 Regional development of nonwoven wipes 115
6.6 Definitions 118
6.7 References 119
7 Nonwovens in specialist and consumer apparel 120
B. J. COLLIER, The Florida State University, USA
7.1 Introduction: key issues and properties required for apparel 120
7.2 Comfort of nonwovens in specialist and consumer apparel 121
7.3 Protection given by nonwovens in specialist and consumer apparel 125
7.4 Life cycle of nonwovens in specialist and consumer apparel 127
7.5 Types of nonwovens for apparel use 127
7.6 Applications of nonwovens in specialist and consumer apparel 128
7.7 Future trends 132
7.8 Sources of further information and advice 134
7.9 References 134
8 Nonwoven textiles for residential and commercial interiors 136
F. KANE, Loughborough University, UK
8.1 Introduction 136
8.2 The interior textiles industry 136
8.3 Nonwovens within interiors 140
8.4 Nonwoven textiles in bedding 142
8.5 Nonwoven textiles in upholstery and furnishing 147
8.6 Nonwoven textiles in wallcoverings 150
8.7 Nonwoven textiles for floor coverings 154
8.8 Summary 157
8.9 References 158
9 The use of nonwovens as textile filtration materials 160
S. ZOBEL and T. GRIES, RWTH Aachen University, Germany
9.1 Introduction 160
9.2 Classification of filters 162
9.3 Filtering mechanisms, technical requirements and standards for nonwoven filtration 166
9.4 Design of nonwoven filters 171
9.5 Common filter designs and applications 178
9.6 Future trends 181
9.7 References 182
10 Nonwoven textiles in automotive interiors 184
J. Y. CHEN, The University of Texas at Austin, USA
10.1 Introduction 184
10.2 Properties required for automotive textiles 190
10.3 Applications 192
10.4 Future trends 200
10.5 References 201
Index 203
Preface
Technical textiles are differentiated from other textiles in that they are designed and made to have particular functional properties and technical performance, rather than having aesthetic or decorative properties.
The term ‘nonwoven’ is unfortunate in that it is an attempt to describe a structure by what it is not. It is not woven, knitted, tufted, stitchbonded or felted. It is not a paper but some nonwovens are paperlike.
‘Textile terms and definitions’ (The Textile Institute) says that opinions vary as to the range of fabrics that are classified as nonwovens. In general a nonwoven is a sheet material made from fibres or filaments that is strengthened by bonding using one or more of several techniques. These include entanglement using barbed needles or fluids, and chemical and thermal bonding. With regard to the definition, there are problems in deciding whether or not wetlaid fabrics containing wood pulp and stitchbonded fabrics should be included. Wetlaid fabrics are distinguished from wetlaid papers by having a higher proportion of fibres with a length to diameter ratio more than 300.
Early nonwovens were made using conventional carding machines designed for carding fibres to make yarns. The carded webs were consolidated or bonded (to provide strength) by one or more methods that included mechanical means (barbed needles, water jets), chemical means (using polymer lattices) and thermal means (for example using fibres that become adhesive when heated). Developments in papermaking and polymer extrusion, especially the extrusion of molten polymers, have extended the range of ways of making nonwovens. Of the latter the development of spunbonding technology was the major leap forward followed by meltblowing, which enabled finer fibres to be made. Recently the introduction of electrospinning has provided a route to even finer fibre nonwovens.
Composite structures made from layers of nonwovens that have been made by different routes or from different fibres are now common. For example combinations of spunbonded and melt fabrics or combinations with nanospun webs.
The wide range of fibre types from natural to ‘manmade’ combined with the availability of so many manufacturing routes provides a wide range of options for the fabric developer who seeks to optimize function, durability and cost. The current interest in green issues has led to a renewed interest in biodegradable fibres and fabrics. Nanotechnology has opened up the possibility of very fine fibre webs being made of both conventional and new fibre types. Smart textiles is leading developments in nonwoven structures that have built-in batteries and energy storage – at the fibre level.
The development of new applications for nonwovens and new fabrics for established applications in particular are seen in nonwoven products for hygiene, building, personal care wipes, household products, filters and automobiles. Of these, hygiene is by far the largest end-use, followed by building applications and personal care wipes.
This book covers the basics of nonwovens – the fibres used, the principal manufacturing routes and the influence of fibre and fabric properties on nonwoven performance, are addressed in Part I. Part II describes many of the main application areas including hygiene, wipes, apparel, building and automotive interiors and filtration.
R. A. Chapman