Patent ID: 7655741
Filing Date: 2010-02-02
Classification: C08F

Abstract:
1. A process for the preparation of vinyl chloride copolymers resistant to coloration upon storage, comprising copolymerizing: a) from 49.5 to 90 weight percent vinyl chloride, b) from 0.01 to 0.4 weight percent of one or more epoxy group-containing vinyl monomers, and c) from 9.5 to 50 weight percent of copolymerizable monomers other than those of a) and b), and d) isolating a solid polyvinyl resin copolymer, wherein during or following the polymerization, but prior to isolating the solid polyvinyl resin copolymer from 0.001 to 0.1 weight percent of one or more carboxylic acids are added, said carboxylic acids selected from the group consisting of saturated mono- and dicarboxylic acids having from 2 to 10 carbon atoms and saturated and unsaturated hydroxy-substituted carboxylic acids having 3 to 10 carbon atoms, 1 to 4 hydroxyl groups, and 1 to 3 carboxylic acid groups.