Patent ID: 7323512
Filing Date: 2008-01-29
Classification: C08L

Abstract:
1. A styrene copolymer composition comprising: (I) a styrene/n-butyl acrylate copolymer comprising 80 to 89% by weight of styrene monomer units and 20 to 11% by weight of n-butyl acrylate monomer units; and (II) a block copolymer having a block configuration comprising (A) at least two polymer blocks each comprised mainly of vinyl aromatic hydrocarbon monomer units and (B) at least one vinyl aromatic hydrocarbon/conjugated diene copolyrner block, said block copolymer (II) comprising 65 to 90% by weight of vinyl aromatic hydrocarbon monomer units and 35 to 10% by weight of conjugated diene monomer units, wherein the vinyl aromatic hydrocarbon monomer unit moiety of said block copolymer (II) has a short segment ratio of from 1 to 25% by weight, wherein said short segment ratio is defined as the weight percentage, based on the total weight of vinyl aromatic hydrocarbon monomer units contained in said block copolymer (II), of the vinyl aromatic hydrocarbon monomer units contained in at least one short segment consisting of 1 to 3 vinyl aromatic hydrocarbon monomer units, wherein said at least two polymer blocks (A) contain a maximum peak molecular weight polymer block exhibiting a maximum peak molecular weight in a gel permeation chromatogram of said at least two polymer blocks (A) and having at least one peak molecular weight in the range of from 30,000 to 150,000, and the content of said maximum peak molecular weight polymer block in said block copolymer (II) is from 20 to 50% by weight, wherein said at least two polymer blocks (A) have a maximum weight polymer block and a minimum weight polymer block, wherein the weight ratio of said maximum weight polymer block to said minimum weight polymer block is from 1.2 to 4.5, and wherein the weight ratio of said styrene/n-butyl acrylate copolymer (I) to said block copolymer (II) is from 10/90 to 90/10.