Patent ID: 7534825

Claim:
Aqueous dispersions of fluorinated polymers, obtained by emulsion polymerization, having a content of fluorinated surfactants lower than 100 ppm referred to the polymer weight and a fluoropolymer concentration from 20 to 75%, referred to the total weight of the dispersion, and having high stability to shear combined with high stability to segregation, said dispersions of fluorinated polymers comprising a nonionic surfactant and one or more anionic surfactants having the following general formula: Y′-(P 1 ) n -CH(Y)-(P 2 ) n′ -Y″ (1) wherein: Y, Y′ and Y″ are anionic or nonionic groups, with the proviso that at least one of Y, Y′ or Y″ is an anionic group and at least one of the remaining of Y, Y′ or Y″ is selected from the group consisting of: COOR, CONHR, CONH 2 , and CONRR′, wherein R and R′, independent from each other, are selected from the group consisting of: C 2 -C 20 linear or branched hydrogenated alkyls, saturated or containing at least one unsaturation of ethylene type, wherein when the alkyl has at least 6 carbon atoms, it can contain one or more aromatic rings, and siloxane alkyl groups, wherein the alkyl contains from 1 to 7 carbon atoms; P 1 and P 2 , equal or different, are linear or branched alkylene groups, optionally containing one or more unsaturations, having a number of carbon atoms from 1 to 10; and n and n′ equal or different, are zero or 1.