| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing the objective polymer with excellent quality in high productivity by carrying out a suspension polymerization of a vinyl chloride monomer, etc., in the presence of an oil-soluble initiator and a dispersion stabilizer in a specific aqueous medium under a specific condition. SOLUTION: A mixture (a vinyl chloride-based monomer) of (A) vinyl chloride monomer and (B) an optional monomer copolymerizable with the component A is subjected to a suspension polymerization in the presence of (C) an oil- soluble polymerization initiator and (D) a dispersion stabilizer in (E) an aqueous medium heated to a temp. of >=40 deg.C, regulated so that the conversion of the vinyl chloride-based monomer to a vinyl chloride-based polymer may be within the range of 0.3-3.0% and the minimum value of a Sauter diameter of a liquid drop of the vinyl chloride-based monomer may be 30-60μm to provide the objective polymer in the method for producing the vinyl chloride-based polymer. As the D component, a partially saponified polyvinyl alcohol or the like having 70-85 mol.% saponification degree and 500-3,000 average polymerization degree is preferably used.
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