Patent ID: 6169139
Filing Date: 2001-01-02
Classification: C08F

Abstract:
A process for preparation of a fluoroelastomer latex which comprises the steps of: A) forming an aqueous emulsion of monomers capable of being copolymerized to form a fluoroelastomer, said emulsion comprising 1) a first monomer selected from the group consisting of vinylidene fluoride and tetrafluoroethylene; 2) at least one other fluorine-containing monomer; 3) a free radical initiator in an amount which catalyzes the free radical emulsion polymerization of said monomers; 4) from about 0.05-3.0 parts by weight per hundred parts monomer of a fluorinated surfactant; and 5) sufficient base to adjust the pH of said emulsion to between 5 to 8; B) polymerizing said emulsion at a temperature of about 40.degree.-130.degree. C. and a pressure of about 2-9 MPa to form a fluoroelastomer emulsion composition; C) adding a sufficient amount of base to adjust the pH of said fluoroelastomer emulsion composition to between 5-9; and D) concentrating said fluoroelastomer emulsion composition which has a pH of 5-9 to form a solids-rich fluoroelastomer latex.