Patent ID: 8426101

Claim:
An organic acid represented by formula (I) and a salt of the organic acid: Z—A—X—B—R (I) wherein Z represents an organic acid group; A represents a divalent linking group; X represents a single bond or a divalent linking group having a hetero atom; B represents an oxygen atom or —N(Rx)-; Rx represents a hydrogen atom or a monovalent organic group; and R represents a monovalent organic group having a bond that is cut by an action of an acid, wherein R, in the formula (I), is a group containing a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkoxyl group, an alkoxycarbonylamino group or a cyano group; and when B represents —N(Rx)-, R and Rx may be bonded to form a ring.