Leather surfacing treatment - using an aq. dispersion of a cationic oligourethane opt. together with basic dyes

摘要

Process for surfacing leather comprises treating the leather with an aq. dispersion of an oligourethane free from NCO gps., with a mol. wt. of 300-20000 and contg. 5-120 milliequivalents cationic gps., per 100 g dry material. The treatment agent may contain brilliant basic dyes to give a coating with a high colouring power. The cationic oligourethane impregnating agents are amde e.g. by reacting (a) di- and/or triisoxyanates, opt. together with monoisocyanates and (b) cpds. contg. at least one gp. which reacts with NCO gps. Component (a) and/or (b) contains basic quaternisable and/or saponifiable gps. The dispersions are applied to the leather without added cross linking agents and dried at 20-130 degrees C, esp. 50-70 degrees C. The finishes give good surfaces on the leather without causing hardening, and penetrate well into the leather.