Method for producing vinyl aromatic resin composition

Abstract

Disclosed is a method for producing a vinyl aromatic resin composition containing a rubber in a disposed state which comprises from 60 to 90% by weight of a copolymer of a vinyl aromatic monomer with an unsaturated dicarboxylic anhydride in which the content of the vinyl aromatic monomer as a monomer unit is from 70 to 98 mol % and the content of the unsaturated dicarboxylic anhydride as a monomer unit is from 2 to 30 mol %, from 10 to 35% by weight of a graft copolymer and from 0 to 9% by weight of a diene based rubber, by copolymerizing the vinyl aromatic monomer with the unsaturated dicarboxylic anhydride in the presence of the diene based rubber, wherein said method comprises. (1) mixing (i) from 2 to 25% by weight of a graft copolymer consisting of (a) from 50 to 85% by weight of a polymer main chain containing a butadiene monomer unit in an amount of 50% by weight or more, (b) from 40 to 5% by weight of a polymethacrylate side chain attached by graft-polymerization to the polymer main chain (a), and (c) from 0 to 40% by weight of a polystyrene side chain attached by graft-polymerization to the polymer main chain (a), or from 2 to 25% by weight in total of the graft copolymer and a diene based rubber, with (ii) from 98 to 75% by weight of a vinyl aromatic monomer, (2) adding (iii) an unsaturated dicarboxylic anhydride to the resulting mixture, and (3) continuing copolymerization reaction of the mixture until the conversion of the vinyl aromatic monomer reaches a value within the range of from 30 to 80% by weight. The resin composition produced by this method can be molded into a molded article having an excellent glossiness, impact strength and heat resistance.

Dependencies are inferred from the claim text.