Page 44 - Basic Principles of Textile Coloration

REFERENCES 33

optimum fastness properties. The diversity of fibres and materials necessitates
different types of dyeing machine (Chapter 12).

Mechanical finishing produces a variety of different effects (Section 25.2). In
calendering, compressing the fabric between rollers under pressure produces a flat,
smooth fabric surface. Raising or napping involves abrading the fabric surface
using sharp steel points to break and lift fibre ends, giving a surface pile.
Compressive shrinking of cotton fabrics avoids shrinkage when a fabric is wetted.
Heat setting of materials made from thermoplastic synthetic fibres stabilises their
shape and dimensions (Section 3.4).

The majority of chemical finishing processes are for fabrics containing cellulosic
fibres (Section 25.4). The chemicals used often form polymers on heating and are
also capable of reacting with the cellulose to generate crosslinks between the
polymer molecules. The result of this is a fabric with improved dimensional
stability to washing, and crease resistance. In addition, there are a large number of
chemical treatments for fabrics that impart specific properties such as water
repellence, softness of handle, flame resistance, easy soil release or resistance to
bacteria.

The effects of the actual finishing processes on the colour characteristics of the
material must be carefully evaluated in advance since finishing can change the
shade of a dyed fabric and modify the fastness properties.

REFERENCES

1. J A Howsmon and W A Sisson, in Cellulose and cellulose derivatives, 2nd Edn, Part 1, E Ott et al., Eds
(New York: Wiley-Interscience, 1954) 251.

2. J G Cook, Handbook of Textile Fibres, 5th Edn (UK: Merrow Publish. Co., 1984).
3. M Lewin and E M Pearce, Eds, Handbook of Fiber Science and Technology, Vol. IV, Fiber Chemistry (New

York: Marcel Dekker, 1985).
4. P G Drexler and G C Tesoro, Handbook of Fiber Science and Technology, Vol. I, Part B, M Lewin and S

B Sello, Eds (New York: Marcel Dekker, 1984).
5. C Crossley, J.S.D.C., 114 (1998) 194.