Fluorinated copolymer, composition, powder coating material, coated article, and method for producing fluorinated copolymer

A method for producing a fluorinated copolymer having units based on chlorotrifluoroethylene and units based on a vinyl ether,

• comprising a step of conducting polymerization in a reactor in which the chlorotrifluoroethylene, the vinyl ether, a solvent and a radical polymerization initiator are present, to produce the fluorinated copolymer,
• wherein after start of the polymerization, a mixture of the chlorotrifluoroethylene and the vinyl ether is supplied to the reactor continuously or intermittently,
• in the reactor before the start of the polymerization, a ratio of a total molar amount of the chlorotrifluoroethylene and the vinyl ether, to a molar amount of the solvent, is 0.30 or higher, and
• a molar ratio A of the vinyl ether to the chlorotrifluoroethylene in the reactor before the start of the polymerization, and a molar ratio B of the vinyl ether to the chlorotrifluoroethylene in the mixture, satisfy the following relation:
• 0
• .
• 5
• ≦
• A
• /
• B
• ≦
• 1.5