Patent ID: 7071271

Claim:
A method of aqueous emulsion polymerization of two or more fluoromonomers comprising the steps of: 1) forming a pre-emulsion by mixing, a fluoromonomer according to formula I: F 2 C═CF—R 1 —SO 2 X (I) wherein R 1 is a branched or unbranched perfluoroalkyl, perfluoroalkoxy or perfluoroether group comprising 1–15 carbon atoms and 0–4 oxygen atoms and wherein X is F, Cl or Br, together with 0.001–0.9 molar equivalents of a base, in the absence of added emulsifier; and 2) reacting said pre-emulsion with one or more comonomers in the absence of added emulsifier, said comonomers being perfluorinated, so as to form a fluoropolymer latex comprising a fluoropolymer wherein more than 1 mol % of monomer units are derived from the fluoromonomer according to formula I.