Patent ID: 7125941

Claim:
Method of making a fluoropolymer through emulsion polymerization of one or more fluorinated monomers in an aqueous phase in the presence of a fluorinated surfactant comprising adding at least part of said fluorinated surfactant to the aqueous phase as an aqueous mixture with at least one organic liquid that is not miscible with water and that is selected from halogenated and non-halogenated organic liquids, said aqueous mixture having droplets having an average droplet diameter of not more than 1000 nm and said aqueous mixture being added to the aqueous phase in such an amount that the total amount of said fluorinated surfactant is not more than 1% by weight based on the weight of the aqueous phase and the total amount of said organic liquid is not more than 1% by weight based on the weight of said aqueous phase, wherein the organic liquid is a perfluorinated or partially fluorinated aliphatic or aromatic organic liquid that contains up to a total of 2 oxygen, sulphur and/or nitrogen atoms per molecule.