Cross linkable fluorine-containing polymer and its production

Abstract

An easily cross linkable fluorine-containing polymer substantially comprising: (1) a polymeric chain comprising one or more polymer segments, of which at least one polymer segment consisting of units of vinylidene fluoride alone or of units of vinylidene fluoride and one or more of other fluoroolefins, and (2) at least one iodine atom liberated from an iodinated compound of the formula: RI.sub.x (wherein R is a saturated or unsaturated fluorohydrocarbon or chlorofluorohydrocarbon residue having 1 to 8 carbon atoms and x is an integer of 1 or 2 corresponding to the bonding valency of the residue R) in an amount of 0.001 to 10% by weight based on the polymer and (3) a fragment of the iodinated compound excluding the said liberated iodine atom therefrom, which are bonded to the polymeric chain and being prepared by polymerizing vinylidene fluoride with or without one or more of the other fluoroolefins in the presence of a radical producing source and the iodinated compound or its reaction product with the said monomer(s) in one or more steps, the other fluoroolefins being selected from the group consisting of tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, vinyl fluoride, hexafluoropropylene, pentafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether) and perfluoro(propyl vinyl ether).