Patent ID: 8859645

Claim:
A process for purifying a fluoropolymer dispersion, said process comprising: (i) providing an aqueous dispersion (D) of at least one fluoropolymer, polymer (F), comprising at least one fluorinated surfactant, surfactant (FS), having a solids content (SC) of 15% by weight or more; (ii) adding to said aqueous dispersion (D) at least one non-ionic non-fluorinated surfactant, surfactant (NS), in an amount of from 1 to 20% by weight of polymer (F); (iii) adjusting said solid content (SC) to less than 10% by weight, to obtain a diluted aqueous dispersion (dD); (iv) contacting said diluted aqueous dispersion (dD) with at least one adsorbing material, wherein the at least one adsorbing material removes fluorinated surfactant (FS) from the diluted aqueous dispersion (dD) so as to obtain an aqueous dispersion of polymer (F) having a content of the fluorinated surfactant (FS) of less than 1 ppm based on the total weight of solids, wherein the at least one adsorbing material comprises beads, the surface of which have active sites that trap and release ions, wherein polymer (F) is a homopolymer of tetrafluorethylene (TFE) or a copolymer of TFE and at least one per(halo)fluoromonomer (PFM), wherein the PFM is selected from the group consisting of: C 2 -C 8 perfluoroolefins, chloro- and/or bromo- and/or iodo- C 2 -C 6 per(halo)fluoroolefins, per(halo)fluoroalkylvinylethers complying with general formula CF 2 ═CFOR f3 , where R f3 is a C 1 -C 6 per(halo) fluoroalkyl, per(halo)fluoro-oxyalkylvinylethers complying with general formula CF 2 ═CFOX 01 , where X 01 is a C 1 -C 12 per(halo)fluorooxyalkyl having one or more ether groups; per(halo)fluoro-methoxy-alkylvinylethers complying with general formula CF 2 ═CFOCF 2 OR f4 , where R f4 is a C 1 -C 6 (perhalo)fluoroalkyl or a C 1 -C 6 per(halo)fluorooxyalkyl having one or more ether groups, and per(halo)fluorodioxoles of formula: where each of R f3 , R f4 , R f5 , R f6 , equal to or different from each other, is independently a fluorine atom or a C 1 -C 6 perfluoroalkyl group, optionally comprising one or more oxygen atoms.