Fluoropolymer dispersions

摘要

Dispersions, obtained starting from a system formed by a (per)fluorinated polymer in polar solvent, comprising at least: 0.1-30% by weight of a polytetrafluoroethylene or of tetrafluoroethylene copolymers with other ethylenically unsaturated, totally or partially fluorinated, monomers; 50-99% by weight of fluorinated liquid; - 0.01-5% by weight of surfactant selected from carboxylic acids with PFPE chain and nonionic surfactants having a perfluoroalkylic or perfluoropolyether chain with a oxyalkylenic repeating unit number lower than or equal to 6; polar solvent (water and/or alcohol) complement to 100; and characterized in that they have a polar solvent/polymer weight ratio lower than that of the initial system containing the (per)fluoropolymer used to prepare the dispersion.