Patent ID: 6297334
Filing Date: 2001-10-02
Classification: C08F,Y10S

Abstract:
A process for preparing dispersions based on tetrafluoroethylene (TFE) homopolymer, or based on copolymers of tetrafluoroethylene (TFE) with one or more monomers containing at least one ethylenic unsaturation in amounts from 0% to 6% by moles, wherein 60% by weight of the particle fraction has an average diameter size in the range 0.005 to 0.06 .mu.m, which comprises:a) preparing an aqueous microemulsion of perfluoropolyethers (PFPE), said perfluoropolyethers having (per)fluorinated terminals, optionally the terminals contain one or more H atoms, and chlorine instead of fluorine;b) feeding said aqueous microemulsion of perfluoropolyethers into a polymerization reactor, in amounts wherein a microemulsion perfluoropolyethereal oil phase is present in a concentration greater than 2 ml per liter of reaction medium;c) feeding a reaction medium into the polymerization reactor, said reaction medium comprising a degassed aqueous component and optionally surfactants, stabilizers, comonomers, and transfer agents;d) pressurizing the polymerization reactor by introducing therein gaseous TFE;e) adding an initiator and optionally during the polymerization adding further amounts of surfactant, stabilizers, comonomer, and transfer agents; andf) discharging from the reactor polymeric latex.