| abstract |
To provide a thermoplastic elastomer composition excellent in fluidity, compression set property, and flexibility, and a hydrogenated block copolymer that provides the composition. The hydrogenated block copolymer is obtained by hydrogenating a block copolymer which is obtained by reacting a living polymer represented by the following formula (1): n B 1 -A-B 2 -X (1)n n wherein B 1 and B 2 each represent a polymer block mainly including a structural unit derived from a conjugated diene compound, A represents a polymer block mainly including a structural unit derived from a vinyl aromatic compound, and X represents an active terminal end of a living anion polymer, with a coupling agent, wherein the ratio of the mass of the polymer block B 1 to the total mass of B 1 and B 2 before hydrogenation is from 0.10 to 0.45; and the content of the structural unit derived from the vinyl aromatic compound is from 25 to 50 mass % based on the mass of the hydrogenated block copolymer. |