Sumitomo Chemical Company, Limited

Satoshi Nakagawa

Hayato Kihara

Shuji Yoshimi

Shinichi Mitsui

A styrene base random copolymer having a weight average molecular weight of 200,000 to 1,000,000, a monovinylbenzene unit and a divinylbenzene unit in an amount of 50 to 500 ppm by weight based on the weight of the monovinylbenzene unit, the divinylbenzene unit consisting of p-divinylbenzene unit and m-divinylbenzene unit, wherein the weight ratio between the p-divinylbenzene unit and the m-divinylbenzene unit is in the range of 100:0 to 75:25, which is superior in impact strength, melt tension, heat resistance and fluidity, and which is capable of being molded within a short molding cycle, is industrially advantageously produced by a continuous bulk polymerization without troubles such as undesirable deposits of polymeric gel material on reactor walls.

Styrene base random copolymer and process for producing the same

Disclosed are a styrene copolymer having a weight average molecular weight of about 200,000 to 2,000,000, having 1 to 20 branching points in the Z-average molecular weight, and having a methyl ethyl ketone/methanol mixture-insoluble matter content of not more than 5% by weight and a methanol-soluble matter content of not more than 5% by weight; processes for preparing the styrene copolymer; a polystyrene resin composition containing the styrene copolymer; and injection-molded article prepared by injection-molding the polystyrene resin composition.

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Ichihara, Japan

Satoshi Nakagawa