Patent ID: 6610779
Filing Date: 2003-08-26
Classification: C08G,C09D

Abstract:
An aqueous polyurethane dispersion, wherein the polyurethane comprises the reaction product ofA) 55 to 75 wt. % of a mixture of 20 to 80 wt. % of an aliphatic polyester diol having a number average molecular weight of 840 to 2100 and 80 to 20 wt. % of an aliphatic polycarbonate diol or polyester carbonate diol having a number average molecular weight of 1000 to 2100, B) 1 to 3 wt. % of a trifunctional, low molecular weight alcohol, C) 20 to 35 wt. % of isophorone diisocyanate and/or hexamethylene diisocyanate, or a mixture of 4,4â€²-diisocyanatodicyclohexyl-methane with isophorone diisocyanate or hexamethylene diisocyanate and D) 3.5 to 4.9 wt. % of dimethylol propionic acid, wherein a neutralizing agent is added in an amount sufficient to neutralize 40 to 105% of the acid groups and an amount sufficient to neutralize at least 40% of the acid groups is added prior to the chain extension reaction, wherein at least 1 wt. % of components A) and B), based on the total weight of components A) to D), are tri- or higher-functional compounds and wherein the polyurethane contains 1 to 4 wt. % of the urea groups set forth in brackets in the following formula: