| abstract |
A hydrogenated block copolymer obtained by selective hydrogenation of a block copolymer comprising at least two polymer blocks (A) which each comprise vinyl aromatic monomer units as the main component and may be the same or different from each other, at least two polymer blocks (B) which each comprise monomer units derived from a conjugated diene of 5 or more carbon atoms as the main component and may be the same or different from each other, and one or more polymer blocks (C) which each comprise monomer units derived from a conjugated diene of 4 or more carbon atoms as the main component and may be the same or different from each other and/or one or more random copolymer blocks (D) which each comprise monomer units (d-1) derived from a conjugated diene of 4 or more carbon atoms and vinyl aromatic monomer units (d-2) as the main components, wherein the degree of hydrogenation of olefinically unsaturated double bonds of the blocks (B) is 50% or below; the degrees of hydrogenation of olefinically unsaturated double bonds of the blocks (C) and (D) are 80% or above; the content of vinyl aromatic monomer units in the block copolymer is 10 to 85% by weight; the contents of A, B, C and D in the block copolymer are 10 to 70% by weight, 1 to 15% by weight, 0 to 85% by weight and 0 to 85% by weight respectively with the proviso that the sum of C and D is 25 to 85% by weight and the sum total of A, B, C and D is 100% by weight; and the weight-average molecular weight (M) of A satisfies the relationship: M > 20000/[1+{content (%) of (d-2)}/20]. |