Patent ID: 6743874
Filing Date: 2004-06-01
Classification: C08F,C08L,C09D

Abstract:
A process for producing liquid fluoropolymers comprising polymerizing, in a non-aqueous solvent without ozone damaging potential, tetrafluoroethylene and optionally other fluorine-containing and/or non-fluorine-containing monomers and at least one compound selected from the group consisting of diiodomethane, 1 ,2-diiodo-1 , 1 -difluoroethane, 1-iodo-2-bromo-1,1-difluoroethane, 1-bromo-2-iodo-1, 1-difluoroethane and/or 1,2-dibromo-1, 1-difluoroethane, in which at least 80% of the terminal groups in the liquid fluoropolymer have the formula â€”CH2â€”I and/or â€”CH2â€”Br and liquid fluoropolymer has a complex viscosity at 100Â° C. and &ohgr;=6.3 sâˆ’1 of 0.01 to 30 kPas and a temperature index, calculated as the quotients of the viscosities at 40 and 100Â° C. of 3 to 250, wherein, the liquid fluoropolymer hasa) more than 10 mol % repeated units derived from tetrafluoroethylene, b) a content of iodine and/or bromine in the range of 0.05 to 1 wt. % and c) an average molecular weight (number average Mn) of over 25,000 g/mol, and wherein the non aqueous solvent is selected from the group consisting of 1,1,1,3,3-pentafluoropropane, perfluorobutane sulphofluride, perfluorosulpholane and a mixture thereof.