PRODUCTION OF VINYL CHLORIDE POLYMER

Japanese Patent JPH1180215

A

PROBLEM TO BE SOLVED: To obtain a high-quality vinyl chloride polymer having a high bulk specific gravity by using a polymerizer having the inner wall coated with a polymer adhesion preventive, by keeping the temp. at the beginning of polymn. at a specified temp. or lower, by lowering the water/monomer ratio, and by specifying the water/monomer ratio at the early stage of polymn. SOLUTION: A vinyl chloride polymer is produced by the suspension polymn. of a vinyl chloride monomer in the presence of an oil-soluble polymn. initiator and a dispersion stabilizer in an aq. medium. A polymerizer having the inner wall coated with an agent which prevents the adhesion of a vinyl chloride polymer is used. The temp. after the completion of charging the aq. medium and the monomer is set at 40 deg.C or lower. The water/monomer ratio (the wt. ratio of an aq. medium/a monomer) after the completion of charging is set at 0.40-0.80 and is adjusted to 0.60-1.20 by the addition of the aq. medium after the temp. of the polymn. system is raised and before the conversion of the monomer into a polymer reaches 10%. Pref., at least one partially saponified polyvinyl alcohol having a degree of saponification of 70-85 mol.% and an average degree of polymn. of 500-3,000 is used as the dispersion stabilizer.

SAWANO MASAO
TANAKA TOSHIHIKO

JP23822997A

March 26, 1999

September 03, 1997

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TOSOH CORP

C08F2/00; C08F2/20; C08F14/00; C08F14/06; (IPC1-7): C08F2/20; C08F2/00; C08F14/06

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