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/EP87/00057 Sec. 371 Date Oct. 28, 1988 Sec. 102(e) Date Oct. 28, 1988 PCT Filed Feb. 6, 1987 PCT Pub. No. WO87/05306 PCT Pub. Date Sep. 11, 1987.The invention relates to dispersions of crosslinked polymer micro-particles in aqueous media, which have been prepared: (1) (a) 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 in which the isocyanate groups are at least partially in the masked form, and the components (A) and/or (B) 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 optionally masked isocyanate, respectively, groups per molecule and (2) (b) 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.