DISPERSIONS OF CROSS-LINKED POLYMER MICRO-PARTICLES IN AQUEOUS MEDIA, PROCESS FOR PREPARING SUCH DISPERSIONS AND COATING COMPOSITIONS CONTAINING SUCH DISPERSIONS

摘要

Dispersions of cross-linked polymer micro-particles in aqueous media are produced by 1) dispersing a mixture of the components (A) and (B) in an aqueous medium. The (A) components are comprised of one or more polyester polyols containing at least two hydroxyl groups, and the (B) components are comprised of one or more polyisocyanate compounds. The (A) components contain a sufficient number of ion groups to form a stable dispersion, preferably carboxylate groups, and at least part of the (A) and/or (B) components contains more than two hydroxyl groups, resp. isocyanate groups per molecule, 2) the dispersion thus obtained is heated until the (A) and (B) components are converted into cross-linked polymer micro-particles.