Patent ID: 7598332

Claim:
A block polymer comprising a repetitive unit structure represented by the formula (2) or (3): formula (2): wherein X′ represents a polyalkenyl group; A represents a linear or branched alkylene group having a carbon atom number of 1 to 15 with or without substitution; m represents an integer from 0 to 30, wherein if m is a plural number, each A is the same or different from each other; B represents a single bond or an alkylene group with or without substitution; D represents an aromatic ring structure with or without substitution; n represents an integer from 0 to 10, wherein if n is a plural number, each D is the same or different from each other; and R represents a hydrogen atom, an alkyl group with or without substitution, or an aromatic ring structure with or without substitution; formula (3): wherein X′ represents a polyalkenyl group; A represents a linear or branched alkylene group having a carbon atom number of 1 to 15 with or without substitution; m represents an integer from 0 to 10, wherein if n is a plural number, each A is the same or different from each other; B represents a single bond or an alkylene group with or without substitution; D represents an aromatic ring structure with or without substitution; n represents an integer from 0 to 30, wherein if m is a plural number, each D is the same or different from each other; and M represents a monovalent or polyvalent metal cation.