Patent ID: 6348521
Filing Date: 2002-02-19
Classification: C07C,C08G,C09D

Abstract:
A process for preparing stable and high-solids aqueous dispersions of blocked isocyanates, containing auxiliary solvent, which comprises:(1) preparing a solution of a polyisocyanate mixture of from 20-70% by weight of a blocked, hydrophilically modified polyisocyanate (A), wherein, in the preparation of blocked, hydrophilically modified polyisocyanate (A), a polyisocyanate starting material is not first subjected to partial blocking and then reacted with hydrophilicizing agent and wherein the blocked, hydrophilically modified polyisocyanate (A) is a blocked, ionic hydrophilically modified polyisocyanate which forms as a result of complete or partial neutralization of a polyisocyanate having a carboxyl group which is neutralized by ammonia or an amine, and from 30-80% by weight of a blocked, hydrophobic polyisocyanate (B) in an auxiliary solvent (G); and (2) adding to this solution, with intensive mixing, an amount of water which is such as to give a two-phase system comprising a disperse polyisocyanate phase and a continuous, aqueous phase containing auxiliary solvent.