Woven Textiles

Principles, Technologies and Applications

K Gandhi

• Publisher: Woodhead Publishing
• Year: 2012
• Print ISBN: 9781845699307
• eBook ISBN: 9780857095589
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Traditionally used in apparel and interior fabrics, woven textiles are increasingly being employed in a variety of technical applications. Woven textiles: Principles, developments and applications provides an essential overview of the manufacture, structure and application of these important textiles.Beginning with an introduction to the fibres and yarns used in weaving, part one goes on to explore key preparatory techniques and the fundamentals of weaving technology. The characteristics of woven structures are then discussed in greater depth in part two, alongside investigation into the use of computer assisted design (CAD) systems, techniques for modelling the structure of woven fabrics, and methods for the manufacture of 3D woven structures. Part three focuses of the application of woven textiles to a wide range of technologies. The use of woven textiles in automotive interiors and other transport applications is discussed, along with woven apparel fabrics, geotextiles, hollow woven fabrics and woven textiles for medical applications.With its distinguished editor and international team of expert contributors, Woven textiles: Principles, developments and applications is an indispensable guide for all designers, engineers and technicians involved in the design, manufacture and use of woven textiles. It also provides a useful overview of woven textile processing and applications for academics and students. - Provides an essential overview of the manufacture, structure and application of woven textiles - Explores key preparatory techniques and the fundamentals of weaving technology and discusses the characteristics of woven structures - Covers the use of computer-assisted design (CAD) systems and methods for the manufacture of 3D woven structures, among other topics

Part I

Yarns and weaving technology

1

Types and properties of fibres and yarns used in weaving

P.K. Hari, Consultant, India

Abstract:

This chapter reviews the types of fibres used in spinning, from natural to regenerated and synthetic fibres. It discusses key fibre properties such as length, linear density/fineness, cross-section and crimp. The chapter also reviews yarn properties such as linear density, diameter, packing and twist as well as fabric properties such as cover, mass, volume and thickness.

Key words

natural fibres

regenerated fibres

synthetic fibres

fibre properties

yarn properties

fabric properties

1.1 Introduction

Woven fabrics consist of interlacements of yarns in two mutually perpendicular directions. Their structure permits a variation in the length and distribution of interlacements, resulting in a range of fabric deformations. Such control also offers scope for the generation of a diverse range of patterns and properties in fabrics. Triaxial fabrics are a special class of woven fabrics in which the warp threads constitute two sheets inclined at different angles, instead of being vertical. The weft thread is interlaced horizontally with the warp; this configuration thus has yarns in the fabric in three axes, hence the term‘triaxial’ fabrics.

The building block of a woven fabric is yarn but the basic unit is fibre. Strength, extension, fineness, length and surface properties are some of the primary attributes of fibres which, using different types or blends of fibres, create a wide spectrum of useful and desirable physical and mechanical properties in the yarn and fabric produced. There are two basic types of fibres or filaments used in yarn:

discontinuous fibres, i.e. short/staple fibres (including most natural fibres); and

continuous fibres (such as silk and synthetic fibres).

Natural fibres have traditionally offered a variety of physical and mechanical properties. Using a natural, regenerated and synthetic filament yarn increases the range of physical and mechanical properties available and, indeed, allows functional properties to be tailor-made for a particular end use. Man-made filaments can be modified by texturing to alter bulk or stretch, or cut to a desired length to produce staple fibres which, either alone or blended with other fibres, are then blended as spun yarns. A knowledge of fibre properties enables a design engineer to select the proper materials to create fabrics for specific end uses.

1.2 Types of natural and regenerated fibres

Cotton, wool, flax and silk are the most important natural textile fibres, followed by fibres such as jute and kenaf. Natural fibres vary in length and in their other properties. They are not consistent and contain unwanted impurities from their original source. Such fibres need to be processed to remove these impurities and reduce the variation in their length. Such fibres can be made coherent, continuous and load bearing by providing sufficient twist to the strand.

The mechanical properties of silk fibres are a combination of high strength, extensibility and compressibility. Jute and kenaf are strong fibres, exhibiting brittle fracture and with a small extension at break; they have high initial modulus but show very little recoverable elasticity. Cotton is the most important natural cellulosic textile fibre. Length and fineness are important measures of fibre quality. Cotton fibres range in dimensions from a length of 5 cm to1.5 cm and a linear density of 1 dtex to 3 dtex. Amongst its many important properties, cotton fibre is hydrophilic and porous; on immersion in water, it swells and its internal pores fill with the water. Chemical modification can add many desired properties to a cotton fabric, including colour, permanent press, flame resistance, soil release and antimicrobial properties.

Regenerated fibres are manufactured from natural polymers. Two of the most widely used regenerated fibres are rayon and acetate. There is a wide variety of different rayon fibres, including regular rayons, high-tenacity rayons, low wet modulus rayons, high wet modulus and modal rayons, high-strength/high-elongation rayons, polynosic rayons, flame-retardant rayons, high absorbency (alloy rayons), hollow rayons and cuprammonium rayons. High-tenacity rayons are used where strength, toughness and durability are required. These fibres are dimensionally stable when used as reinforcement in tyres, conveyor belts, drive belts and hoses. Other applications for this type of rayon include industrial sewing threads, tent fabrics and tarpaulins.

A range of cross-sectional shapes such as round, flat, Y-shaped, E-shaped, U-shaped, T-shaped and irregular (crenulated) shaped fibres are produced in rayon. It is generally accepted that the crenulated structure is formed by greater shrinkage of the fibre skin than of the core. Given its aesthetic properties, particularly its silk-like sheen, finer denier fibres are used for shawls, scarves, blouses and coat linings. Blends with cotton, polyester and flax help overcome inherent defects such as poor dimensional stability and mushy hand. Polynosic rayon fibres have high wet and dry strength, low elongation (8–11%), relatively low water retention and a very high wet modulus of 1 g/den. They have the firm and crisp hand of cotton in fabrics.

Cellulose acetate and triacetate textile fibres produce fabrics with an excellent hand, good dyeability, softness (comfort) and draping quality. The traditional market for cellulose acetate and triacetate fabrics is women’s apparel. Acetate yarns are used for both tricot knit and woven constructions. Principal products within women’s apparel include dresses, blouses and lingerie. Acetate has replaced rayon as a liner in men’s suits and in non-apparel applications such as curtains. Cellulose triacetate offers the unique combination of ‘ease-of-care’ and aesthetic properties. A particularly important application of triacetate is in surface-finished fabrics such as fleece, velour and suede-like fabrics for dresses. Tri...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributor contact details
• Woodhead Publishing Series in Textiles
• Part I: Yarns and weaving technology
• Part II: Woven structures
• Part III: Applications of woven textiles
• Index