Patent ID: 8835585

Claim:
A copolymer resulting from a reaction of components (A) to (C): (A) an ester compound obtained by adding 0 to 10 moles of C 2-4 alkylene oxide to 1 mole of at least one compound of Formula (1): RO-(AO) n -H (1) where R is a C 1-12 alkyl group, A is a C 2-4 alkylene group, and n is an integer of 0 to 7 indicating the number of addition moles of alkylene oxide, and then subjecting the resulting adduct to a reaction with an α,β-unsaturated carboxylic acid, in which the compound of Formula (1) contains not more than 5% by mass of the constituent compounds having n of 3 or less relative to the total mass of the compound of Formula (1), (B) an α,β-unsaturated carboxylic acid or a salt thereof, and (C) optionally another copolymerizable monomer; or a salt thereof.