Patent ID: 7932333

Claim:
A process comprising polymerizing at least one fluorinated monomer in an aqueous medium containing initiator and polymerization agent to form an aqueous dispersion of particles of fluoropolymer, said polymerization agent comprising: monofunctional fluoropolyether acid or salt thereof having a number average molecular weight of about 1000 to about 2500 g/mol; and fluoropolyether acid or salt surfactant being a compound of the formula: [R 1 —O-L 1 -O-L 2 -A − ]Y + wherein: R 1 is a linear or branched partially or fully fluorinated aliphatic group which may contain ether linkages; L 1 and L 2 are a linear or branched alkylene groups which may be the same or different nonfluorinated, partially fluorinated or fully fluorinated and which may contain ether linkages; A − is an anionic group selected from the group consisting of carboxylate, sulfonate, sulfonamide anion and phosphonate; and Y + is hydrogen, ammonium or alkali metal cation, said fluoropolyether acid or salt surfactant having a molecular weight of about 300 to about 500 g/mol.