Patent ID: 7919557

Claim:
A process for producing an aqueous coating composition comprising a dispersion of a fluorocopolymer (A), which fluorocopolymer (A) comprises the following units (1) to (4), wherein a proportion of the repeating unit (4) is from 1.4 mol % to 3.9 mol % based on the total repeating units, and an aqueous medium, wherein an amount of an organic solvent contained in the composition is from 0 to 1 mass %: Unit (1): a repeating unit of a fluoroolefin, Unit (2): a repeating unit of a vinyl monomer or an allyl monomer, and neither a hydroxyl group nor a carboxyl group which may form a salt, is bonded to the unit, Unit (3): a repeating unit of a vinyl monomer having a hydroxyl group bonded thereto or of an allyl monomer having a hydroxyl group bonded thereto, and a carboxyl group which may form a salt, is not bonded to the unit, and Unit (4): a repeating unit of a vinyl monomer or an allyl monomer, which is also a repeating unit to which a carboxylate group in which a part may be a carboxyl group, is bonded, the process comprising carrying out sequentially: (a) a step of a copolymerization reaction by a solution polymerization method in an organic solvent to obtain a fluorocopolymer (B) containing the unit (1), the unit (2), the unit (3) and a polymerized unit (4-3) derived from a monomer having a carboxyl group bonded thereto; (b) neutralizing a part or whole of the carboxyl group in the fluorocopolymer (B) by adding a basic compound, thereby forming fluorocopolymer (A); (c) adding water; and (d) removing the organic solvent.