Patent ID: 7112637
Filing Date: 2006-09-26
Classification: C08F

Abstract:
1. A process for producing a vinyl chloride-based polymer, wherein a suspension polymerization of either vinyl chloride monomer, or a mixture of vinyl chloride monomer and another copolymerizable monomer, is conducted in a polymerization vessel fitted with a reflux condenser, said process comprising: (A) adding to a reaction mixture a high-activity, oil-soluble polymerization initiator, with a 10-hour half life temperature of no more than 40° C. at a concentration of 0.1 mol/L in benzene, for a specified time within a period from commencement of heat removal using said reflux condenser through to completion of polymerization, (B) adding water either continuously or intermittently to said reaction mixture through a supply pipe for said polymerization initiator, at least during a period from commencement of addition of said high-activity, oil-soluble polymerization initiator through to completion of said addition, and (C) passing steam through said supply pipe following completion of addition of said water.