Method for producing fluorinated polymer and method for producing fluorinated ion exchange polymer

A method for producing a fluorinated polymer, the method comprising:

• synthesizing a perfluoromonomer represented by formula m11 to obtain a crude product C1 further containing a fluorinated monomer m11H represented by formula m21, and/or synthesizing a perfluoromonomer represented by formula m12 to obtain a crude product C2 further containing a fluorinated monomer m12H represented by formula m22;
• purifying the crude product C1 to adjust a content of the fluorinated monomer m11H to obtain a monomer composition M11 containing the perfluoromonomer m11 and the fluorinated monomer m11H, and/or purifying the crude product C2 to adjust a content of the fluorinated monomer m12H to obtain a monomer composition M12 containing the perfluoromonomer m12 and the fluorinated monomer m12H;
• mixing at least one of the monomer composition M11 and the monomer composition M12, wherein a total amount of the fluorinated monomer m11H and the fluorinated monomer m12H to a total amount of the monomer composition M11 and the monomer composition M12 is from 10 to 1,100 ppm, with at least one monomer selected from the group consisting of tetrafluoroethylene, a monomer represented by formula m31, a monomer represented by formula m32, a monomer represented by formula m33, a monomer represented by formula m34, a monomer represented by formula m35, a monomer represented by formula m36, and a monomer represented by formula m37, thereby obtaining a raw material mixture, wherein a proportion of the total amount of the monomer composition M11 and the monomer composition M12 in a total amount of all monomers contained in the raw material mixture is from 20 to 90 mol %;
• and
• polymerizing the raw material mixture:
• where R11, R12 and R14 are each independently a fluorine atom, a C1-10 perfluoroalkyl group, or a group having an etheric oxygen atom between carbon-carbon atoms in a C2-10 perfluoroalkyl group, and
• R13 is a single bond, a C1-10 perfluoroalkylene group or a group having an etheric oxygen atom between carbon-carbon atoms in a C2-10 perfluoroalkylene group;
• where
• Q is a single bond, a C1-10 perfluoroalkylene group, or a group having an etheric oxygen atom between carbon-carbon atoms in a C2-10 perfluoroalkylene group,
• q is 0 or 1,
• Y1 is a fluorine atom or a monovalent perfluoroorganic group,
• Q1 is a perfluoroalkylene group which optionally has an etheric oxygen atom,
• Q2 is a single group, or a perfluoroalkylene group which optionally has an etheric oxygen atom,
• m is 0 or 1, and when p is 0, m is 0,
• p is 0 or 1
• n is an integer of from 1 to 12,
• X is a fluorine atom or a trifluoromethyl group,
• r is an integer of from 1 to 3,
• t is 0 or 1,
• s is an integer of from 1 to 12,
• RF1 and RF2 are each independently a C1-3 perfluoroalkylene group, and RF3 is a C1-6 perfluoroalkylene group.