Patent ID: 7470747
Filing Date: 2008-12-30
Classification: B29C,C08F,C08J,C08L,Y10T

Abstract:
1. A block copolymer mixture comprising block copolymers (A), (B) and (C): (i) from 20 to 60 mass % of a block copolymer (A), which comprises as monomer units, from 75 to 95 mass % of a vinyl aromatic hydrocarbon and from 5 to 25 mass % of a conjugated diene, wherein the block copolymer (A), at least at one terminal, has a block portion that comprises a vinyl aromatic hydrocarbon having a number average molecular weight ranging from 30,000 to less than 150,000, and wherein block copolymer (A) has a number average molecular weight ranging from 100,000 to less than 300,000; (ii) from 20 to 70 mass % of a block copolymer (B), which comprises as monomer units, from 50 to 80 mass % of a vinyl aromatic hydrocarbon and from 20 to 50 mass % of a conjugated diene, wherein the block copolymer (B), at least at one terminal, has a block portion that comprises a vinyl aromatic hydrocarbon having a number average molecular weight ranging from 20,000 to less than 120,000, wherein the block copolymer (B) has, from 10 to 70 mass % of at least one random copolymer block portion comprising, as monomer units, from 55 to 95 mass % of a vinyl aromatic hydrocarbon and from 5 to 45 mass % of a conjugated diene and wherein the block copolymer (B) further has from 15 to 45 mass % of at least one random (co)polymer block portion comprising, as monomer units, from 0 to less than 55 mass % of a vinyl aromatic hydrocarbon and from greater than 45 to 100 mass % of a conjugated diene, and wherein block copolymer (B) has an entire number average molecular weight ranging from 50,000 to less than 200,000; (iii) from 5 to 50 mass % of a block copolymer (C), which comprises as monomer units, from 60 to 95 mass % of a vinyl aromatic hydrocarbon and from 5 to 40 mass % of a conjugated diene, wherein the copolymer has at least one random copolymer block portion comprising, as monomer units, from 55 to 95 mass % of a vinyl aromatic hydrocarbon and from 5 to 45 mass % of a conjugated diene, and wherein block copolymer (C) has a number average molecular weight ranging from 200,000 to less than 300,000.