Water-based fluorine-containing emulsion

A water-based fluorine-containing emulsion comprising:

• a fluorine-containing copolymer that consists essentially of 10-70 mol % of a first structural unit derived from a fluoroolefin, 0.1-20 mol % of a second structural unit derived from an organosilicon compound containing an olefinic unsaturated bond and an alkoxysilyl group, 0.1-20 mol % of a third structural unit derived from an unsaturated carboxylic acid represented by a general formula of CH.sub.2 .dbd.CH--(CH.sub.2).sub.n --COOH where n is an integer of from 3 to 15, and 30-85 mol % of a fourth structural unit derived from at least one other copolymerizable monomer, based on a total number of moles of all of said first, second, third and fourth structural units.

A method for producing a water-based fluorine-containing emulsion having a fluorine-containing copolymer, the method comprising a step of:

• copolymerizing, in a medium containing water, (A) 10-70 mol % of a fluoroolefin, (B) 0.1-20 mol % of an organosilicon compound containing an olefinic unsaturated bond and an alkoxysilyl group, (C) 0.1-20 mol % of an unsaturated carboxylic acid represented by a general formula of CH.sub.2 .dbd.CH--(CH.sub.2).sub.n --COOH where n is an integer of from 3 to 15, and (D) 30-85 mol % of at least one other copolymerizable monomer, based on a total number of moles of all of said fluoroolefin, said organosilicon compound, said unsaturated carboxylic acid, and said at least one other copolymerizable monomer, in order to prepare said fluorine-containing copolymer in said medium.