AQUEOUS POLYMERIZATION OF FLUORINATED MONOMER USING POLYMERIZATION AGENT COMPRISING FLUOROPOLYETHER ACID OR SALT AND SHORT CHAIN FLUOROSURFACTANT

摘要

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, the polymerization agent comprising: fluoropolyether acid or salt thereof having a number average molecular weight of at least about 800 g/mol; and fluorosurfactant having the formula: [R¹-O_n-L-A] Y⁺ wherein: R¹ is a linear or branched partially or fully fluorinated aliphatic group which may contain ether linkages; n is 0 or 1; L is a linear or branched alkylene group which may be 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; with the proviso that the chain length of R¹-0_n-L- is not greater than 6 atoms.