| 摘要 |
A hydrogenated aromatic vinyl copolymer obtained by hydrogenating a block copolymer comprising monomer units including an aromatic vinyl monomer and a conjugated diene monomer, wherein the block copolymer includes (A) 75 to 92% by mass of a constituent unit derived from the aromatic vinyl monomer and (B) 8 to 25% by mass of a constituent unit derived from the conjugated diene monomer (with the proviso that (A)+(B)=100% by mass) and is a branched block copolymer with a specific block structure which has a weight average molecular weight of 100,000 to 300,000, and 97% or more of the aromatic rings derived from the aromatic vinyl monomer and the double bonds derived from the conjugated diene monomer are hydrogenated. The hydrogenated aromatic vinyl copolymer has excellent transparency, excellent impact resistance, low water absorption, and a small birefringence index.
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