Patent ID: 8653019

Claim:
A copolymer comprising: (a) a fluorine-containing acrylate of the general formula (1): H 2 C═CXCOO—Y—R f wherein X is a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a CFX 1 X 2 group (wherein X 1 and X 2 is a hydrogen atom, a fluorine atom or a chlorine atom), a cyano group, a linear or branched fluoroalkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted benzyl group, or a substituted or unsubstituted phenyl group; Y is an aliphatic group having 1 to 10 carbon atoms, an aromatic or cycloaliphatic group having 6 to 10 carbon atoms, a —CH 2 CH 2 N(R 1 )SO 2 — group (in which R 1 is an alkyl group having 1 to 4 carbon atoms) or a —CH 2 CH(OY 1 )CH 2 — group (in which Y 1 is a hydrogen atom or an acetyl group); and Rf is a linear or branched polyfluoroalkyl group having less than 8 carbon atoms, and (b) a fluorine-free (meth)acrylate of the general formula (2): H 2 C═CXCOO—(RO) n —X wherein X is a hydrogen atom or a methyl group, R is an alkylene group having 2 to 6 carbon atoms, and n is an integer of 2 to 50, and wherein the fluorine-free (meth)acrylate of the general formula (2) is polymerized at the C═C position and the COO—(RO) n —X in formula (2) exists as a side chain in the copolymer.