| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method for a vinyl chloride-based polymer whereby a high quality vinyl chloride-based polymer less in fine particles, high in bulk specific gravity and less in fish eye generation is easily and efficiently obtained. SOLUTION: The production of the vinyl chloride-based polymer is carried out by the followings. When producing the vinyl chloride-based polymer by suspension polymerization of vinyl chloride-based monomers in an aqueous medium, such 3 requirements are simultaneously satisfied that (1) Pv of net stirring power of a polymerization reactor, is controlled to 1.0-3.0 kW/m<SP>3</SP>per 1 m<SP>3</SP>reaction mixture during the period from starting of the polymerization up until the conversion reaches at least 30%, (2) T (pts.wt.) of the total amount of a suspending agent per 100 pts.wt. vinyl chloride-based monomer, satisfies the formula: T<0.024+0.015×Pv, and (3) the surface tension of the aqueous medium containing the suspending agent and suspending auxiliaries at starting of the polymerization at 25°C is at most 45 dyne/cm. COPYRIGHT: (C)2007,JPO&INPIT
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