Patent ID: 6890978

Claim:
An aromatic monovinyl resin composition comprising (a) a polymer comprising an aromatic monovinyl monomer and having a weight average molecular weight of 150,000-700,000 and (b) at least one 3-arylbenzofuranone selected from the group consisting of 5,7-di-tert-butyl-3-(2,4-dimethylphenyl)-3H-benzofuran-2-one, 5,7-di-tert-butyl-3-(2,5-dimethylphenyl)-3H-benzofuran-2-one or 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-3H-benzofuran-2-one, wherein amount of the 3-arylbenzofuranone is 0.006-0.5% by weight based on the weight of the polymer and residual amount of the aromatic monovinyl monomer in the aromatic monovinyl resin composition is not more than 100 ppm.