Patent ID: 9156920
Filing Date: 2015-10-13
Classification: C08F

Abstract:
1. A process for preparing an aqueous emulsifier-stabilized vinyl acetate-ethylene copolymer dispersion with fine particle size, comprising emulsion polymerization of a reaction mixture comprising: a) vinyl acetate and ethylene, b) 0.05 to 1% by weight, based on the total weight of monomers and comonomers, of at least one functional comonomer selected from the group consisting of ethylenically unsaturated monomers possessing at least one phosphate group or phosphonic acid group or their salts and ethylenically unsaturated sulphonic acids or their salts, c) 0.5 to 5% by weight, based on the total weight of monomers and comonomers, of at least one anionic emulsifier and optionally one or more nonionic emulsifiers, and d) 0 to 0.5%, based on the total weight of monomers and comonomers, of a protective colloid, wherein the emulsion polymerization is performed in a reactor with an external heat exchange circuit comprising a pump and a heat exchanger, and during the emulsion polymerization the reaction mixture is circulated through the external heat exchange circuit, wherein the copolymer dispersion as formed contains less than 1000 ppm of coagulum, and wherein the copolymer dispersion particles have a weight average particle size Dw in a range from 100 nm to 300 nm.