PURPOSE: To obtain the titled polymer for paste, having easily adjustable polymerization rate, providing low-viscosity plastisol, by carrying out seeding emulsion polymerization using a catalyst comprising a specific organic hydroperoxide emulsion and a water-soluble reducing agent.
CONSTITUTION: In subjecting vinyl chloride or a mixture of vinyl chloride and a vinyl compound (e.g., vinyl acetate, etc.) copolymerizable with it to seeding emulsion polymerization in an aqueous medium in the presence of a redox polymerization catalyst comprising a water-soluble reducing agent (e.g., ethylenediaminetetraacetic acid, etc.) and an organic hydroperoxide, an organic hydroperoxide composition consisting of 5W10wt% ≥6C organic hydroperoxide and 95W0wt% ≤5C organic hydroperoxide is used as the organic hydroperoxide, and these organic hydroperoxides as an aqueous emulsion are fed to the polymerization system continuously or dividedly to effect polymerization.
TAKEUCHI SOUICHIROU
NAKANO AKIRA
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