Dyeing Polyacrylonitrile Fibres with Cationic Dyes

Methods for predicting the dyeing behaviour of cationic dyes on acrylic fibres (of Orion 42 and Dralon types) are of value, since the existence of saturation values, the poor levelling characteristics of the dyes used, and the pronounced dependence of exhaustion rate on dye concentration and temperature demand careful control of the whole dyeing process. The nature of the bond between the fibre and the dye, and the dependence of dyeing equilibrium on dyeing conditions are considered, and equations are derived for calculating the dye uptake of single dyes and of mixtures. Finally, methods of achieving levelness of dyeings are discussed.