Method for manufacturing fluorine-containing polymer

A method of producing a fluorine-containing polymer comprising a first polymer formed from a first monomer, and a second polymer formed from a second monomer,

• wherein the method comprises the steps of:
• (I) polymerizing the first monomer to obtain the first polymer, and
• (II) charging and polymerizing the second monomer in the presence of the first polymer to obtain the second polymer,
• at least one of the first monomer and the second monomer comprises a fluorine-containing monomer (a),
• both of the first monomer and the second monomer comprise a halogenated olefin monomer (b),
• the first monomer comprises a fluorine-free non-crosslinkable monomer (c) which is other than the halogenated monomer (b),
• the fluorine-containing monomer (a) is represented by the formula:
• CH2═C(—X)—C(═O)—Y—Z—Rf
• wherein
• X is a hydrogen atom, a monovalent organic group or a halogen atom;
• Y is —O— or —NH—;
• Z is a direct bond or divalent organic group;
• Rf is a fluoroalkyl group having 4 to 6 carbon atoms, and the fluorine-free non-crosslinkable monomer (c) is represented by the formula:
• CH2═CA-T
• wherein A is a hydrogen atom, a methyl group, or a halogen atom other than a fluorine atom, T is a hydrogen atom, an open-chain or cyclic hydrocarbon group having 1 to 30 carbon atoms, or an open-chain or cyclic organic group having 1 to 31 carbon atoms and having an ester bond.