Patent ID: 7060741

Claim:
A polymer composition comprising: I) at least one graft rubber polymer obtained by emulsion polymerization of styrene and acrylonitrile in a weight ratio of 95:5 to 50:50, wherein the styrene and/or the acrylonitrile can be partially or completely replaced by α-methylstyrene, methyl methacrylate or N-phenyl-maleimide or mixtures thereof, in the presence of a butadiene polymer latex (A) with a mean particle diameter d 50 of 230 to 330 nm; II) at least one graft rubber polymer obtained by emulsion polymerization of styrene and acrylonitrile in a weight ratio of 95:5 to 50:50, wherein the styrene and/or the acrylonitrile can be partially or completely replaced by α-methylstyrene, methyl methacrylate or N-phenylmaleimide or mixtures thereof, in the presence of a butadiene polymer latex (B) with a mean particle diameter d 50 of 340 to 480 nm; III) at least one graft rubber polymer obtained by emulsion polymerization of styrene and acrylonitrile in a weight ratio of 95:5 to 50:50, wherein the styrene and/or the acrylonitrile can be partially or completely replaced by α-methyl styrene, methyl methacrylate or N-phenylmaleimide or mixtures thereof, in the presence of a butadiene polymer latex (C); and IV) at least one rubber-free copolymer of styrene and acrylonitrile in a weight ratio of 95:5 to 50:50 wherein the styrene and/or the acrylonitrile can be partially or completely replaced by α-methyl styrene, methyl methacrylate or N-phenylmaleimide or mixtures thereof; wherein the butadiene polymer latices (A) and (B) are obtained by seed polymerization using at least one butadiene polymer latex (C) with a mean particle diameter of 10 to 220 nm as seed latex, and the graft rubber component III) is obtained by graft polymerization in the presence of at least one butadiene polymer latex (C) used as seed latex for (A) and (B).