PROCESS FOR PRODUCING FLUOROPOLYMERS

• US 20090124755A1
• Filed: 10/21/2008
• Published: 05/14/2009
• Est. Priority Date: 11/09/2007
• Status: Abandoned Application

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: DuPont Performance Elastomers LLC (Corteva, Inc.)
• Inventors: Hung, Ming-Hong, Tang, Phan Linh, Coughlin, Michael Cregg
• Application Number:
  US12/255,142
• Publication Number:
  US 20090124755A1
• Time in Patent Office: Days
• US Class Current: 524/746
• CPC Class Codes: C08F 14/26 Tetrafluoroethene
• CPC Class Codes: C08F 2/22 Emulsion polymerisation
• CPC Class Codes: C08F 2/26 anionic
• CPC Class Codes: C08F 214/262 with fluorinated vinyl ethers

Abstract

An emulsion polymerization process for the production of fluoropolymers that contain polymerized units of tetrafluoroethylene is disclosed wherein a perfluoroaliphatic sulfinate is employed as dispersant.

Claims

1. An emulsion polymerization process for the production of a fluoropolymer selected from the group consisting of homopolymers and copolymers of tetrafluoroethylene, said process comprising polymerizing tetrafluoroethylene in an aqueous medium comprising initiator and dispersing agent to obtain an aqueous dispersion of fluoropolymer, wherein said dispersing agent consists essentially of at least one perfluoroaliphatic sulfinate.

2. The process of claim 1 wherein said perfluoroaliphatic sulfinate is of the formula R_f—

SO₂M, where R_f is a perfluoroalkyl group or a perfluoroalkoxy group containing 1 to 20 carbon atoms and M is a cation having a valence of 1.

3. The process of claim 2 wherein said R_f is a perfluoroalkyl group or a perfluoroalkoxy group containing 4 to 10 carbon atoms.

4. The process claim 3 wherein said perfluoroaliphatic sulfinate is of the formula C₄F₉—

SO₂Na;

C₆F₁₃—

SO₂Na;

C₈F₁₇—

SO₂Na;

C₃F₇—

O—

CF₂CF₂—

SO₂Na.

5. The process of claim 1 wherein said perfluoroaliphatic sulfinate is of the formula R_f′

—

(SO₂M)_n where R_f′

is a polyvalent perfluoro radical containing 1 to 20 carbon atoms, M is a cation having a valence of 1 and n is an integer from 2-4.

6. The process of claim 5 wherein R_f′

is a perfluoroalkylene radical containing 4 to 10 carbon atoms.

7. The process of claim 6 wherein said perfluoroaliphatic sulfinate is of the formula C₆F₁₂—

(SO₂Na)₂.

8. The process of claim 1 wherein said fluoropolymer is a homopolymer of tetrafluoroethylene.

9. The process of claim 1 wherein said fluoropolymer is a copolymer of tetrafluoroethylene.

10. The process of claim 1 wherein at least one comonomer is copolymerized with tetrafluoroethylene, said at least one comonomer selected from the group consisting of fluorine-containing olefins, fluorine-containing vinyl ethers and hydrocarbon olefins.

11. The process of claim 10 wherein said fluorine-containing olefin is selected from the group consisting of vinylidene fluoride, hexafluoropropylene, 1,2,3,3,3-pentafluoropropene, 1,1,3,3,3-pentafluoropropene, chlorotrifluoroethylene and vinyl fluoride.

12. The process of claim 10 wherein said fluorine-containing vinyl ether is a perfluoro(alkyl vinyl ether).

13. The process of claim 10 wherein said hydrocarbon olefin is selected from the group consisting of ethylene and propylene.

14. The process of claim 1 wherein said fluoropolymer is a fluoroelastomer comprising copolymerized units selected from the group consisting of i) vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene;

ii) vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene and 4-bromo-3,3,4,4-tetrafluorobutene-1;

iii) vinylidene fluoride, hexafluoropropylene, tetrafluoroethylene and 4-iodo-3,3,4,4-tetrafluorobutene-1;

iv) vinylidene fluoride, perfluoro(methyl vinyl)ether, tetrafluoroethylene and 4-bromo-3,3,4,4-tetrafluorobutene-1;

v) vinylidene fluoride, perfluoro(methyl vinyl)ether, tetrafluoroethylene and 4-iodo-3,3,4,4-tetrafluorobutene-1;

vi) vinylidene fluoride, perfluoro(methyl vinyl)ether, tetrafluoroethylene and 1,1,3,3,3-pentafluoropropene;

vii) tetrafluoroethylene, perfluoro(methyl vinyl)ether and ethylene;

viii) tetrafluoroethylene, perfluoro(methyl vinyl)ether, ethylene and 4-bromo-3,3,4,4-tetrafluorobutene-1;

ix) tetrafluoroethylene, perfluoro(methyl vinyl)ether, ethylene and 4-iodo-3,3,4,4-tetrafluorobutene-1;

x) tetrafluoroethylene, propylene and vinylidene fluoride;

xi) tetrafluoroethylene and perfluoro(methyl vinyl)ether;

xii) tetrafluoroethylene, perfluoro(methyl vinyl)ether and perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene);

xiii) tetrafluoroethylene, perfluoro(methyl vinyl)ether and 4-bromo-3,3,4,4-tetrafluorobutene-1;

xiv) tetrafluoroethylene, perfluoro(methyl vinyl)ether and 4-iodo-3,3,4,4-tetrafluorobutene-1; and

xv) tetrafluoroethylene, perfluoro(methyl vinyl)ether and perfluoro(2-phenoxypropyl vinyl)ether.