Patent ID: 7981985

Claim:
A polymer comprising a structural unit represented by the formula (Ia) or (Ib): wherein R 1 represents a hydrogen atom or a methyl group, R 2 represents a linear, branched chain or cyclic C1-C8 alkyl group, R 3 represents a methyl group, n represents an integer of 0 to 14, Z 1 represents a single bond or —[CH 2 ] k —COO—, k represents an integer of 1 to 4, R 4 and R 5 each independently represents a hydrogen atom or a C1-C8 monovalent hydrocarbon group which may have at least one heteroatom, or R 4 and R 5 may be bonded to form a C1-C8 divalent hydrocarbon group which may have at least one heteroatom which forms a ring together with the adjacent carbon atoms to which R 4 and R 5 are bonded, or R 4 and R 5 may be bonded to form a carbon-carbon double bond between the carbon atom to which R 4 is bonded and the carbon atom to which R 5 is bonded, and m represents an integer of 1 to 3, a structural unit represented by the formula (II): wherein R 6 and R 7 each independently represents a hydrogen atom, a methyl group or a hydroxyl group, R 8 represents a methyl group, R 9 represents a hydrogen atom or a methyl group, Z 2 represents a single bond or —[CH 2 ] k′ —COO—, k′ represents an integer of 1 to 4, n′ represents an integer of 0 to 12, Z′ represents a group capable to eliminate by an action of an acid, and a structural unit represented by the formula (III): wherein R 10 is independently in each occurrence a carboxyl group, a cyano group or a C 1-C4 hydrocarbon group, R 11 represents a hydrogen atom or a methyl group, 1′ represents an integer of 0 to 3, Z 3 represents a single bond or —[CH 2 ] k″ —COO —, and k″ represents an integer of 1 to 4.