| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a vinyl chloride-based polymer in which the method is improved by conducting an aqueous suspension polymerization in a polymerization vessel equipped with a reflux condenser, is capable of shortening the polymerization time by effectively utilizing the heat removal ability, and provides a polymer having reduced fish eyes and good quality. SOLUTION: The manufacturing method of a vinyl chloride-based polymer comprises suspension-polymerizing a vinyl chloride monomer or a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith in a polymerization vessel equipped with a reflux condenser, wherein the method comprises (A) adding a highly active, oil-soluble polymerization initiator, having a 10-hr half-life temperature of 40°C or below that is given at the concentration of 0.1 mol/L in benzene, to the reaction mixture for a certain period of time within the period between the beginning of the removal of heat by the reflux condenser and the termination of the polymerization, and (B) adding continuously or intermittently a partially saponified polyvinyl alcohol having a degree of saponification of 25-56 mol% to the reaction mixture for at least a period of time from the beginning and to the end of the addition of the initiator. COPYRIGHT: (C)2005,JPO&NCIPI
|
