Aqueous emulsion polymerization process for producing fluoropolymers

摘要

The present invention provides a 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. At least part of the fluorinated surfactant is added 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, the mixture having droplets having an average droplet diameter of not more than 1000 nm and the mixture being added to the aqueous phase in such an amount that the total amount of the 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. The invention allows for an improvement of the efficiency of an aqueous emulsion polymerization process. In particular, the polymerization time can be reduced and the polymer yield may be improved.