Patent ID: 7683144
Filing Date: 2010-03-23
Classification: C08F

Abstract:
1. A process for chain stopping vinyl chloride polymerization, which process comprises adding to a vinyl chloride polymerization reaction system a) a stable free nitroxyl radical and b) a phenolic antioxidant wherein the reaction system comprises initial unreacted vinyl chloride monomer or unreacted vinyl chloride monomer and partially polymerized vinyl chloride monomer, where the nitroxyl radical is of formula (A), (B) or (O) wherein G G R, if m is 1, is hydrogen, C R, if m is 2, is C R is a divalent radical of a phosphorus-containing acid or a divalent silyl radical; R, if m is 3, is a trivalent radical of an aliphatic, cycloaliphatic or aromatic tricarboxylic acid; R, if m is 4, is a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetracarboxylic acid; p is 1; R R