Fluorinated elastic copolymer, and method for producing fluorinated elastic copolymer

A method for producing a fluorinated elastic copolymer having units based on the following monomer (a), units based on the following monomer (b) and optionally units based on the following monomer (c), which comprises

• polymerizing a monomer component comprising the monomer (a) and optionally the monomer (c) and not including the monomer (b), in the presence of an iodine compound having two iodine atoms until units in an amount of at least 80 mol % to all units of the fluorinated elastic copolymer are formed, and
• copolymerizing monomer components comprising the monomer (a), the monomer (b) and optionally the monomer (c) until the units based on the monomer (b) in an amount of from 0.09 to 2.0 mol % to all units of the fluorinated elastic copolymer are formed:
• monomer (a):
• a monomer selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, chlorotrifluoroethylene, a perfluoro(alkyl vinyl ether) and 2,3,3,3-tetrafluoropropene;
• monomer (b):
• a monomer having at least one adhesive functional group selected from the group consisting of an epoxy group and a hydroxy group, and having one polymerizable carbon-carbon double bond;
• monomer (c):
• a monomer selected from the group consisting of ethylene and propylene.