THE INTERACTION OF KNITTING OILS AND COTTON IMPURITIES - EFFECTS ON REACTIVE DYE YIELD

The problems facing the modern dyehouse due to the presence of impurit ies on cotton fibres from a variety of sources are discussed. A list o f impurities normally assignable to natural cotton is included to emph asise the complexity of the chemistry influencing the pretreatment sta ge. The importance of effective systems management during pretreatment is highlighted. A laboratory study has been undertaken to investigate the action of three different types of needle oil on reactive dye yie ld when dyeing cotton. Oleophilic dyes increased in dye yield when the oil was not adequately removed in preparation, as expected. This inve stigation explains some of the less common but previously puzzling occ urrences of dye-resist effects, demonstrating that this may be associa ted in some way with knitting oils.