Page 31 - Basic Principles of Textile Coloration

20 FIBRES AND TEXTILES: PROPERTIES AND PROCESSING

CHAPTER 2

Fibres and textiles: properties and
processing

This chapter on textile production complements the brief introduction in Section
1.2.2. It reviews some properties of fibres, their conversion into yarns and fabrics,
and the objectives of wet processing in manufacturing textiles. The emphasis is on
the relationship between dyeing and textile properties and processes. Table 1.1 in
the previous chapter identified the seven major fibre types: cotton, wool, viscose,
cellulose acetates, nylons, polyesters and acrylics. Later chapters will consider the
production, characteristics and dyeing of all these fibres.

2.1 PROPERTIES OF FIBRES
A fibre is characterised by its high ratio of length to thickness, and by its strength
and flexibility. Fibres may be of natural origin, or artificially made from natural or
synthetic polymers. They are available in a variety of forms. Staple fibres are short,
with length-to-thickness ratios around 103 to 104, whereas this ratio for
continuous filaments is at least several millions. The form and properties of a
natural fibre such as cotton are fixed, but for artificially made fibres a wide choice
of properties is available by design. The many variations include staple fibres of
any length, single continuous filaments (monofilaments), or yarns constituted of
many filaments (multi-filaments). The fibres or filaments may be lustrous, dull or
semi-dull, coarse, fine or ultra-fine, circular or of any other cross-section, straight
or crimped, regular or chemically modified, or solid or hollow. The lustre and
handle depend on the shape of the cross-section and on the degree of crimping
developed in a process called texturising (Section 3.4).

Natural fibres have a number of inherent disadvantages. They exhibit large
variations in staple length, fineness, shape, crimp, and other physical properties,
depending upon the location and conditions of growth. Animal and vegetable
fibres also contain considerable and variable amounts of impurities whose removal
before dyeing is essential, and entails much processing. Artificially made fibres are
much more uniform in their physical characteristics. Their only contaminants are
small amounts of slightly soluble low molecular weight polymer (oligomers) and

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