Patent ID: 8058319

Claim:
A method to produce a polymer dispersion, comprising the steps of: a) providing a solution comprising a solvent for a polymer and said polymer containing pendant SO 2 X groups, wherein the polymer comprises a fluorinated backbone and pendant groups described by the formula â€”(Oâ€”CF 2 CFR f ) a â€”(Oâ€”CF 2 ) b â€”(CFRâ€² f ) c SO 2 X, where X is a halogen, R f and Râ€² f are independently selected from F, Cl or a perfluorinated alkyl group having 1 to 10 carbon atoms, a=0 to 2, b=0 to 1, and c=0 to 6; b) combining the solution of step a) with a nucleophilic compound Y and a polar liquid, to form a reaction mixture; and c) removing by distillation substantially all of the solvent used in step (a) for dissolving the polymer containing pendant â€”SO 2 X group from the reaction mixture of step b) to form a dispersion wherein about 5% to about 95% of the pendant SO 2 X groups have reacted with the nucleophilic compound Y and about 95% to about 5% of the pendant SO 2 X groups remain unreacted.