Reducing the telogenic behavior of hydrocarbon-containing surfactants in aqueous dispersion fluoromonomer polymerization

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.

2. The process according to claim 1 wherein the metal of said metal ion is selected from Mn, Fe, Co, Ni, Cu, Zn, Ce, and Ag.

3. The process according to claim 1 where the metal ion is ferrous ion or cuprous ion.

4. The process according to claim 1 wherein the amount of passivation adjuvant is 2 wt % or less than 2 wt % based on the total weight of the hydrocarbon-containing surfactant added to the polymerization reactor.

5. The process according to claim 1 wherein the hydrocarbon-containing surfactant is passivated prior to addition to the polymerization reactor.

6. The process according to claim 1 wherein the hydrocarbon-containing surfactant is passivated during or after addition to the polymerization reactor.

7. The process of according to claim 6 wherein said hydrocarbon containing surfactant is passivated by reacting said hydrocarbon-containing surfactant with polymerization initiator.

8. The process according to claim 7 wherein said hydrocarbon-containing surfactant is added to the polymerization reactor after commencement of said polymerizing.

9. The polymerization process according to claim 8 further comprising adding passivation adjuvant to the polymerization reactor after commencement of said polymerizing.

10. The polymerization process according to claim 9 wherein said passivation adjuvant is present in the polymerization reactor when said stabilizing surfactant is added.

11. The process according to claim 1 wherein said fluoropolymer particles are polytetrafluoroethylene particles and said polymerizing is carried out to wherein said dispersion of polytetrafluoroethylene particles constitute 45 wt % or greater than 45 wt % of said aqueous medium.

12. The process according to claim 11 wherein 3000 ppm or greater than 3000 ppm of said hydrocarbon-containing surfactant is added to said reactor.

13. The polymerization process according to claim 1 wherein the passivation of said hydrocarbon-containing surfactant reduces its telogenic effect, which is characterized by an increase in space-time-yield of said polymerizing of at least 10% as compared to a polymerization process wherein said hydrocarbon-containing surfactant is not passivated.

14. The process of claim 1 wherein the fluoropolymer of the dispersion of fluoropolymer particles produced by the process is perfluoroplastic.

15. A fluoropolymer dispersion made by the process according to claim 1 .

16. A fluoropolymer resin made by isolation from the fluoropolymer dispersion of claim 15 .