Patent ID: 6965003

Claim:
A block copolymer comprising a polymer block [A] and a polymer block [B], in which: (i) the polymer block [A] contains a repeating unit[1] represented by the following formula (1) in a proportion of 50 mol % or more, where R 1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, R 2 to R 12 each represents independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, or a halogen atom; (ii) the polymer block [B] contains said repeating unit [ 1 ], and at least one repeating unit selected from the group consisting of a repeating unit [ 4 ] represented by the following formula (4), where R 13 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and a repeating unit [ 5 ] represented by the following formula (5), where R 14 and R 15 each represents independently a hydrogen atom or an alkyl group having 1 to 20 carbon atoms; and the molar fraction m 2 (mol %) of the repeating unit [ 4 ] and the molar fraction m 3 (mol %) of the repeating unit [ 5 ] in said polymer block [B] satisfy the relationship represented by the following expression: 2 ×m 2 +m 3 ≧2(mol %); (iii) the molar fraction a (mol %) of the repeating unit [ 1 ] in the polymer block [A] and the molar fraction b (mol %) of the repeating unit [ 1 ] in the polymer block [B] satisfy the relationship represented by a>b; and (iv) the weight average molecular weight falls in the range from 10,000 to 300,000.