Peroxide-curable fluoroelastomers having bromine an iodine curesites and the preparation thereof

Claim 1

A composition comprising a peroxide curable fluoroelastomer prepared by continuous emulsion polymerization in the presence of iodinated compounds of the formula RI n , where R is a saturated hydrocarbon radical of 1-12 carbon atoms, I is iodine, and n is 1 or 2, said iodine being bonded at a substantial number of terminal positions on the fluoroelastomer, the amount of iodinated compound being sufficient to provide at least 0.1 weight percent iodine in the fluoroelastomer, comprising: (a) up to 3 weight percent based on the total weight of components (a) and (b), of polymer repeat units selected from the group consisting of fluoroolefins and fluorovinyl ethers, said units containing bromine and being present in an amount present to provide 0.1-1.0 weight percent bromine in the fluoroelastomer; and (b) complementally, at least 97 weight percent, based on the total weight of components (a) and (b), of: (1) polymer repeat units of vinylidene fluoride, and polymer repeat units of one or more fluoroolefins copolymerizable therewith, said fluoroolefins containing 2-8 carbon atoms and at least as many fluorine atoms as carbon atoms, or (2) 32-60 mole percent of polymer repeat units of tetrafluoroethylene, 20-40 mole percent of polymer repeat units of perfluoroalkyl perfluorovinyl ethers, and 10-40 mole percent of polymer repeat units of ethylene.