Patent ID: 7217760

Claim:
A fluorine-containing water- and oil-repellent composition comprising a copolymer having units derived from: (a) a perfluoroalkyl group-containing ethylenically unsaturated monomer in the amount of 40 to 95% by weight, (b) an ethylenically unsaturated monomer having a group wherein a halogen atom or a halogenated methyl group is bonded to an aromatic ring in the amount of 0.1 to 10% by weight, (c) an ethylenically unsaturated monomer copolymerizable with the monomers (a) and (b) in the amount of 0.1 to 60% by weight, and (d) a functional group-containing ethylenically unsaturated monomer in the amount of 0 to 10% by weight, the copolymer being prepared by emulsion-polymerizing the monomers (a) to (d) in the presence of a surfactant, and the copolymer being dispersed in a water-based medium with a surfactant, wherein the ethylenically unsaturated monomer (b) is chloromethylstyrene or chlorostyrene.