Patent ID: 7888429

Claim:
A process for preparation of epoxy-modified vinyl chloride-vinyl ester copolymers as a solid resin, comprising free radically polymerizing an aqueous mixture comprising a) from 50 to 90 percent by weight of vinyl chloride, b) from 5 to 25 percent by weight of one or more epoxide-containing vinyl monomers b), selected from the group consisting of methyl glycidyl methacrylate, methyl glycidyl acrylate, allyl glycidyl ether, allylphenol glycidyl ether and glycidyl methacrylate, and c) from 5 to 25 percent by weight of one or more vinyl esters of straight-chain or branched alkylcarboxylic acids having from 1 to 18 carbon atoms c), selected from the group consisting of vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methyl vinyl acetate, vinyl pivalate and vinyl esters of α-branched monocarboxylic acids having 9 to 13 carbon atoms, and d) from 0 to 40 percent by weight of further monomer(s) d), different from a), b), and c), and copolymerizable with a), b) and c), the further monomers being selected from the group consisting of (meth)acrylate esters of C 1-18 branched or straight chain alcohols and mixtures thereof, the percents by weight of a), b), c), and d) totaling 100% by weight, and subsequently drying an aqueous dispersion obtained thereby, wherein said polymerizing is effected by means of suspension polymerization with from 0.02 to 5 weight percent of one or more aldehyde regulators, and wherein from 0.005 to 0.05 weight percent of ascorbic acid and/or isoascorbic acid, and optionally from 0.001 to 0.1 weight percent of citric acid, based on the total weight of monomers a) through d) are present during and/or after polymerizing but prior to drying the aqueous dispersion to form a solid product.