Patent ID: 8680208

Claim:
A star polymer comprising, as an arm portion, a polymer chain consisting of repeating units represented by formula (I) and formula (II): wherein R 1 represents a hydrogen atom or a methyl group, R 2 represents an alkyl group, an alkoxy group, or an aryl group, R 3 represents a methyl group, R 4 represents an alkyl group which may have a hydroxy group, or a cycloalkyl group, and n represents any integer of 0 to 3, and comprising a core portion derived from a monomer represented by formula (III): wherein (A) represents an m-valent linking group, R 5 represents a hydrogen atom or a methyl group, and m represents an integer of 2 or more, wherein a molar ratio of the repeating unit represented by formula (I) to the repeating unit represented by formula (II) ((I)/(II)) in the arm portion is in the range of 60/40 to 95/5.