Aqueous dispersions of cross-linked polymer particles, process for the preparation of these dispersions and coating compositions containing these dispersions

摘要

PCT No. PCT/EP87/00056 Sec. 371 Date Aug. 26, 1988 Sec. 102(e) Date Aug. 26, 1988 PCT Filed Feb. 6, 1987 PCT Pub. No. WO87/05305 PCT Pub. Date Sep. 11, 1987.Dispersions of crosslinked polymer micro-particles in aqueous media, a process for the preparation of these dispersions, and coating compositions containing these dispersions. The invention relates to dispersions of crosslinked polymer micro-particles in aqueous media, which have been prepared: (1) by dispersing a mixture of the components (A) and (B) in an aqueous medium, the component (A) being composed of one or more polyester-polyols containing at least 2 hydroxyl groups, and the component (B) being composed of one or more polyisocyanate compounds, and the component (A) having available a number of ionic groups, preferably carboxylate groups, sufficient to form a stable dispersion, and at least one part of the components (A) and/or (B) containing more than 2 hydroxyl or isocyanate, respectively, groups per molecule and (2) by subsequently heating the dispersion thus obtained to a temperature sufficiently high for the components (A) and (B) to react to form crosslinked polymer micro-particles.