Patent ID: 9074025
Filing Date: 2015-07-07
Classification: C08F,C09D

Abstract:
1. A process for polymerizing fluoromonomer to form a dispersion of fluoropolymer particles in an aqueous medium in a polymerization reactor, which comprises adding to the polymerization reactor: aqueous medium, polymerization initiator, fluoromonomer, and hydrocarbon-containing surfactant, and passivating the hydrocarbon-containing surfactant, said passivating being carried out by reacting said hydrocarbon-containing surfactant with an oxidizing agent selected from the group consisting of hydrogen peroxide and polymerization initiator, said passivating being carried out in the presence of a passivation adjuvant comprising transition metal ion, wherein the hydrocarbon-containing surfactant is a compound of the formula R-L-M wherein R is an alkyl group containing from 6 to 17 carbon atoms, L is selected from the group consisting of —ArSO 3 − , —SO 3 − , —OSO 3 , —PO 3 − and —COO − , wherein Ar is an aryl group, and M is a univalent cation selected from H + , Na + , K + and NH 4 + , wherein no halogen-containing surfactant is added to the aqueous medium, and wherein the fluoropolymer is selected from the group consisting of polytetrafluoroethylene, modified polytetrafluoroethylene, and melt-processible compolymer comprising at least 40-99 mol % tetrafluoroethylene units and about 1-60 mol % of at least one other monomer.