METHOD FOR PRODUCING COPOLYMER DISPERSIONS OF NARROW PARTICLE SIZE DISTRIBUTION WITH A WIDE CONCENTRATION RANGE OF DILATANT FLOW BEHAVIOR.

摘要

A process for the preparation of copolymer dispersions having a narrow particle size distribution, and exhibiting dilatant flow over a broad range of concentrations, by emulsion copolymerization of from 1 to 10% by weight, based on total monomers, of alpha , beta -monoolefinically unsaturated monocarboxylic acids and/or dicarboxylic acids with other monoolefinically unsaturated monomers and with from 0 to 5% by weight of polyolefinically unsaturated monomers in the presence of conventional emulsifiers, dispersants and polymerization initiators, and in the presence or absence of regulators, wherein the monomers are copolymerized in aqueous emulsion, with simultaneous agglomeration but only partial fusion of the initially formed polymer particles, at a temperature near the glass transition temperature of the copolymer formed, and thereafter (A) the copolymer content of the aqueous copolymer dispersion is brought to 35-55% by weight and the pH to 3-5 or (B) the water contained in the aqueous copolymer dispersion is entirely or partially replaced by a water-miscible liquid which does not dissolve or swell the copolymer.