Patent ID: 8637623

Claim:
A polymeric compound comprising at least a monomeric unit represented by following Formula (I): wherein R a represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; R 1 s are substituents bound to the ring and each represent a halogen atom, an alkyl or haloalkyl group having 1 to 6 carbon atoms, a hydroxyalkyl or hydroxyhaloalkyl group having 1 to 6 carbon atoms whose hydroxyl moiety may be protected by a protecting group, a carboxyl group which may form a salt, or a substituted oxycarbonyl group; “A” represents an alkylene group having 1 to 6 carbon atoms, an oxygen atom, a sulfur atom, or nonbonding; “m” is the number of R 1 s and denotes an integer of 0 to 8; Xs each independently represent an electron-withdrawing substituent selected from the group consisting of: fluorine-containing group, acyloxy group, cyano group, nitro group, sulfo group, alkanesulfonyl group, alkanesulfinyl group and alkoxysulfonyl group, and wherein at least one X is bound directly to the alpha position of the carbonyl group of the lactone ring; “n” is the number of Xs bound to the ring and denotes an integer of 1 to 9; and Y represents a methylene or a group composed of an alkylene group having 1 to 3 carbon atoms and an alkylene group having 1 or 2 carbon atoms bound with each other through an ester bond, wherein the —COO—Y—COO— group bound to the polymer chain may have either endo or exo configuration.