PROCESS FOR PRODUCING PTFE AND ARTICLES THEREOF

• US 20130040142A1
• Filed: 04/28/2011
• Published: 02/14/2013
• Est. Priority Date: 04/28/2010
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Frey, Oliver, Hintzer, Klaus, Neumann, Wolfgang, Streiter, Andr
• Granted Patent: US 11,072,671 B2
• Time in Patent Office: Days
• US Class Current: 428/402
• CPC Class Codes: C08F 2/24 with the aid of emulsifying agents
• CPC Class Codes: C08F 214/262 with fluorinated vinyl ethers
• CPC Class Codes: D01F 6/12 from polymers of fluorinated hydrocarbons
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

Described herein is a process for making PTFE having a standard specific gravity of less than 2.160 g/cm³ comprising: polymerizing a tetrafluoroethylene monomer in an aqueous medium comprising an emulsifier and an initiator in a reaction vessel and contacting the aqueous medium with a fluorinated polyether. Also described herein are the polymerizable compositions and articles thereof.

Claims

1. A PTFE latex comprising a polymerizable composition comprising:

an amount of water;

a tetrafluoroethylene monomer;

an emulsifier;

an initiator; and

a fluorinated polyether

wherein the PTFE latex has a particle size of at least 150 nm and the coagulated PTFE has a standard specific gravity of less than 2.160 g/cm³.

2. The PTFE latex according to claim 1, wherein the fluorinated polyether is at least 0.1% by weight versus the amount of water.

3. The PTFE latex according to claim 1, wherein the fluorinated polyether is selected from at least one of:

CHF₂CF₂CF₂OCF(CF₃)CF₂OCFHCF₃, CHF₂CF₂CF₂OCF(CF₃)CF(CF₃)OCF₂CF₂CHF₂, CF₃CF₂CF₂OCF(CF₃)CF(CF₃)OCF₂CF₂CF₃, CF₃(OCF(CF₃)CF₂)_n(OCF2)_mOCF₃ wherein n and m are independently, within the range of 1 to 5, CF₃CF₂CF₂O[CF(CF₃)CF₂O]_nCFXCF₃ wherein X is selected from H, F, or CF₃ and n is within the range of 2 to 8, [C₃F₇O[CF(CF₃)CF₂O]_nCF(CF₃)—

]₂ wherein n is within the range of 1 to 3, [C₃F₇OCF(CF₃)CF₂OCF(CF₃)CF₂OCF(CF₃)]₂, [C₃F₇OCF(CF₃)CF₂OCFHCF₂—

]₂, and including all isomers and combinations thereof.

4. The PTFE latex according to claim 1, wherein the fluorinated polyether has a boiling point of between 50 to 300°

C.

5. The PTFE latex according to claim 1, wherein the fluorinated polyether has a molecular weight of less than 2000 grams/mole.

9. The PTFE latex according to claim 1, wherein the emulsifier is selected from a perfluorinated alkanoic acid, a perfluorinated or partially fluorinated acid comprising one or more ether linkages, or their salts.

10. The PTFE latex according to claim 1, wherein the emulsifier is a partially fluorinated emulsifier and the fluorinated polyether is partially fluorinated.

11. The PTFE latex according to claim 1, further comprising a seed particle.

13. The PTFE latex according to claim 1, wherein the PTFE is essentially free of alkane hydrocarbons having between 15 to 60 carbon atoms.

26. An article made from the PTFE latex according to claim 1, wherein the article is a garment, fiber, or sheet.

6. (canceled)

7. (canceled)

8. (canceled)

12. (canceled)

14. A process for making PTFE comprising:

polymerizing a tetrafluoroethylene monomer in an aqueous medium comprising an emulsifier and an initiator in a reaction vessel, contacting the aqueous medium with a fluorinated polyether to form a PTFE latex, and coagulating and drying the PTFE coagulation, wherein the PTFE latex has a particle size of at least 150 nm and the coagulated PTFE has a standard specific gravity of less than 2.160 g/cm³.

15. The process according to claim 14, wherein the weight ratio of the fluorinated polyether to emulsifier is greater than 1:

1.

17. The process according to claim 14, wherein the fluorinated polyether is added separately from the emulsifier.

18. The process according to claim 14, wherein the fluorinated polyether is selected from at least one of:

CHF₂CF₂CF₂OCF(CF₃)CF₂OCFHCF₃, CHF₂CF₂CF₂OCF(CF₃)CF(CF₃)OCF₂CF₂CHF₂, CF₃CF₂CF₂OCF(CF₃)CF(CF₃)OCF₂CF₂CF₃, CF₃(OCF(CF₃)CF₂)_n(OCF2)_mOCF₃ wherein n and m are independently, within the range of 1 to 5, CF₃CF₂CF₂O[CF(CF₃)CF₂O]_nCFXCF₃ wherein X is selected from H, F, or CF₃ and n is within the range of 2 to 8, [C₃F₇O[CF(CF₃)CF₂O]_nCF(CF₃)—

]₂ wherein n is within the range of 1 to 3, [C₃F₇OCF(CF₃)CF₂OCF(CF₃)CF₂OCF(CF₃)]₂, [C₃F₇OCF(CF₃)CF₂OCFHCF₂—

]₂, and including all isomers and combinations thereof.

20. The process according to claim 14, wherein the emulsifier is a non-telogenic partially fluorinated emulsifier and the fluorinated polyether is partially fluorinated.

21. The process according to claim 14, wherein the reaction vessel is a vertical kettle.

22. The process according to claim 14, further comprising seeding the polymerization with a seed particle.

23. The process according to claim 14, wherein the polymerization is conducted at a temperature of at most 80°

C.

24. The process according to claim 14, wherein the PTFE has a P_n of at least 500,000.

25. A PTFE made by the process according to claim 14.

16. (canceled)

19. (canceled)