Polymerization process

• US 5,688,884 A
• Filed: 08/20/1996
• Issued: 11/18/1997
• Est. Priority Date: 08/31/1995
• Status: Expired due to Term

• Current Assignee: The Chemours Company FC, LLC (The Chemours Company)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Zipfel, Roger John, Baker, Bruce Edward
• Primary Examiner(s): Schofer, Joseph L.
• Assistant Examiner(s): Sarofin, N.
• Application Number:
  US08/700,258
• Time in Patent Office: 455 Days
• Field of Search: 526/225
• US Class Current: 526/225
• CPC Class Codes: C08F 14/26 Tetrafluoroethene
• CPC Class Codes: C08F 2/16 Aqueous medium

Abstract

Compound of the formula C₆ F₁₂ --CH₂ CH₂ --SO₃ M wherein M is a cation having a valence of 1 is used as a dispersing agent in the aqueous dispersion polymerization of tetrafluoroethylene.

Claims

1. In the process of polymerizing tetrafluoroethylene in an aqueous medium containing initiator and dispersing agent to obtain an aqueous dispersion of polytetrafluoroethylene particles, the improvement comprising carrying out the polymerization wherein said dispersing agent is a compound of the formula C₆ F₁₃ --CH₂ CH₂ --SO₃ M, wherein M is a cation having a valence of 1.

2. In the process of claim 1 wherein perfluorinated copolymerizable comonomer is present in said aqueous medium, whereupon said polytetrafluoroethylene contains said comonomer in an amount less than 0.5 mol %.

3. In the process of claim 1 wherein said comonomer is perfluoroolefin or perfluoro(alkyl vinyl ether).

4. In the process of claim 1 wherein M is hydrogen.

5. In the process of claim 1 wherein said polytetrafluoroethylene made using said compound has a melt viscosity of at least 1×

10⁹ Pa.s.

6. In the process of claim 1 wherein said polytetrafluoroethylene made using said compound has a raw dispersion particle size of 0.15 to 0.35 micrometers.