Shrink-Resisting Reduced Wool with Synthappret LKF

Abstract

The level of shrink-resistance that can be achieved by the application of a polyether polyurethane, Synthappret LKF, to wool fabric can be substantially increased if the wool is reduced with sodium bisulphite or tri-n-butyl phosphine. The effect is reversed by treatments that remove thiol groups. The reductive pretreatment also increases the adhesion between the wool and the polymer. Because the improved shrink-resistance is apparently dependent on the presence of thiol groups in the reduced wool, it is suggested that the thiol groups react with the isocyanate groups of the polymer. Such a reaction would be expected to increase the adhesion between wool and polymer and thereby increase the level of shrink-resistance.