Patent ID: 7915337

Claim:
A surface treatment agent, which is a polymer dispersion in water, comprising: (1) a fluorine-containing polymer comprising: (A) repeating units derived from a fluorine-containing monomer of the formula: wherein X is a chlorine atom, 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 (wherein R 1 is an alkyl group having 1 to 4 carbon atoms) or a —CH 2 CH(OY 1 )CH 2 — group (wherein Y 1 is a hydrogen atom or an acetyl group), and Rf is a linear or branched fluoroalkyl group having 1 to 6 carbon atoms, (B) repeating units derived from a monomer free from a fluorine atom, and (C) optionally present, repeating units derived from a crosslinkable monomer; (2) an emulsifying agent; and (3) water, wherein the concentration of the fluorine-containing polymer in the surface treatment agent, which is in the form of a solution or an emulsion, is from 0.01 to 50% by weight.