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AssigneeSumitomo Chemical Company, Limited
InventorsSatoshi Nakagawa, Shuji Yoshimi, Hayato Kihara
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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.
A process for producing a styrene based random copolymer by continuous bulk polymerization, which process comprises subjecting a monomer mixture comprising a monovinylbenzene and a divinylbenzene to continuous bulk polymerization, the monomer mixture comprising the divinylbenzene being present in an amount of 50 to 500 ppm by weight based on the weight of the monovinylbenzene, the divinylbenzene consisting of p-divinylbenzene and m-divinylbenzene, wherein the weight ratio between the p-divinylbenzene and the m-divinylbenzene is in the range of 100:0 to 75:25.
Dependencies are inferred from the claim text.