Page 207 - Basic Principles of Textile Coloration

196 AN INTRODUCTION TO DYES AND DYEING

pad, with all the dyes added, pre-dryer, dryer, a Thermosol unit for fixation of the
disperse dye in the polyester, cooling cylinders, a second pad containing chemicals
for fixation of the cotton dyes, a steamer to promote this, several sections of
washing boxes and final drying cylinders.

The degree of dye fixation is never 100% and any unfixed dye must be removed
from the fabric by rinsing and washing, otherwise the optimum fastness properties
will not be attained. Washing may be carried out in a conventional dyeing
machine or continuously. Continuous washers for removal of surface and unfixed
dyes usually consist of several sections of coupled washing boxes with
countercurrent flow of the washing solution. The box is either filled with water
and the fabric passes up and down between rollers, or water is sprayed onto the
fabric that passes horizontally between rollers. The dyed and washed fabric is
finally dried on heated cylinders (hot cans). Section 12.6 has more information on
continuous dyeing equipment.

REFERENCES

1. T Vickerstaff, The Physical Chemistry of Dyeing, 2nd Edn (London: Oliver & Boyd, 1968).
2. J Park, A Practical Introduction to The Continuous Dyeing of Woven Fabrics (Leek: Roaches

International, 1990).
3. D G Duff and R S Sinclair, Giles’s Laboratory Course in Dyeing (Bradford: SDC, 1989).
4. W Ingamells, Colour for Textiles – A User’s Handbook (Bradford: SDC, 1993).