Patent ID: 6242512
Filing Date: 2001-06-05
Classification: C04B,C08L,C09D,Y10S

Abstract:
Process for the preparation of a redispersible dispersion powder composition by drying an aqueous mixture comprising:a) a water-insoluble base polymer having a glass transition temperature of -60.degree. C. to +80.degree. C. from the group consisting of homo- and copolymers of vinyl esters, acrylic acid esters, methacrylic acid esters, styrene and vinyl chloride, or a mixture of the base polymers mentionedb) 2 to 40% by weight, based on the base polymer, of a water-soluble atomizing protective colloid, andc) 0 to 30% by weight, based on the total weight of polymeric constituents, of an antiblocking agent,wherein component b) comprises non-neutralized homo- or copolymers of olefinically unsaturated mono- or dicarboxylic acids or anhydrides thereof, or partly neutralized copolymers of olefinically unsaturated mono- or dicarboxylic acids or anhydrides thereof having an acid content of >80 mol % in the case of copolymers with C.sub.3 - to C.sub.12 -alkenes or styrene and an acid content of 50 to 99 mol % in the case of the other copolymers, the molecular weight of the polymers mentioned being 250,000 g/mol, determined as the weight-average, and wherein the pH of the mixture prior to drying is adjusted to a pH of less than 4.5.