Porous membrane

• US 6,770,202 B1
• Filed: 02/04/2002
• Issued: 08/03/2004
• Est. Priority Date: 04/14/1999
• Status: Expired due to Fees

• Current Assignee: Pall Corporation (Danaher Corporation)
• Original Assignee: Pall Corporation (Danaher Corporation)
• Inventors: Gsell, Thomas C., Kidd, Stanley
• Primary Examiner(s): Kim, John
• Application Number:
  US09/958,490
• Time in Patent Office: 911 Days
• Field of Search: 210/321.6, 210/321.75, 210/483, 210/488, 210/500.21, 210/500.27, 210/500.36, 210/640, 210/649, 210/650, 210/651, 210/652, 210/653, 264/41, 96/4, 96/5, 96/6, 96/14, 436/177, 436/178
• US Class Current: 210/650
• CPC Class Codes: B01D 2323/12 Specific ratios of components used
• CPC Class Codes: B01D 2325/022 Asymmetric membranes
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 61/145 Ultrafiltration
• CPC Class Codes: B01D 61/147 Microfiltration
• CPC Class Codes: B01D 61/32 Controlling or regulating
• CPC Class Codes: B01D 61/36 Pervaporation; Membrane distillation; Liquid permeation
• CPC Class Codes: B01D 67/0009 by phase separation, sol-gel transition, evaporation or solvent quenching
• CPC Class Codes: B01D 69/02 characterised by their properties

Abstract

The present invention provides integral porous membranes comprising an amorphous halopolymer, as well as processes for preparing the membranes, and devices comprising the membranes. An example of an amorphous halopolymer is a copolymer of tetrafluoroethylene and perfluoro-2,2-dimethyl-1,3-dioxole.

Claims

1. An integral porous membrane comprising an amorphous halopolymer comprising a fluorocopolymer including tetrafluoroethylene and a perfluoro-1,3-dioxole, wherein the porous membrane has a pore size of from about 0.1 μ

m to about 10 μ

m.

2. The integral porous membrane of claim 1, wherein said perfluoro-1,3-dioxole is perfluoro-2,2-dimethyl-1,3-dioxole.

3. The integral porous membrane of claim 2, wherein said copolymer includes from about 10% to about 40% by mole of tetrafluoroethylene and from about 90% to about 60% by mole of perfluoro-2,2-dimethyl-1,3-dioxole.

4. The integral porous membrane of claim 2, wherein said copolymer includes from about 30% to about 40% by mole of tetrafluoroethylene and from about 70% to about 60% by mole of perfluoro-2,2-dimethyl-1,3-dioxole.

5. The integral porous membrane of claim 2, wherein said copolymer includes about 35% by mole of tetrafluoroethylene and about 65% by mole of perfluoro-2,2-dimethyl-1,3-dioxole.

6. The integral porous membrane of claim 2, wherein said copolymer includes about 15% by mole of tetrafluoroethylene and about 85% by mole of perfluoro-2,2-dimethyl-1,3-dioxole.

7. The integral porous membrane of claim 1, wherein the membrane has an asymmetric structure.

8. The integral porous membrane of claim 1, wherein the membrane has a symmetric structure.

9. The integral porous membrane of claim 1, which is a microfiltration membrane.

10. The integral porous membrane of claim 1, which is an ultrafiltration membrane.

11. The integral porous membrane of claim 1, which is a sheet.

12. The integral porous membrane of claim 1, which is unsupported.

13. The integral porous membrane of claim 1, which is supported.

14. The membrane of claim 1, wherein said amorphous halopolymer is soluble in a solvent at ambient temperatures.

15. The membrane of claim 14, wherein said solvent is a fluorinated solvent.

16. The membrane of claim 1, wherein the amorphous halopolymer has a degree of crystallinity less than about 30%.

28. A device comprising a housing including an inlet and an outlet defining a fluid flow path between the inlet and the outlet, and the membrane of claim 1 disposed across the fluid flow path.

29. A device comprising a housing, at least one inlet and at least one outlet defining a fluid flow path between the inlet and the outlet, and the membrane of claim 1 disposed tangentially to the fluid flow path.

30. A process for treating a contaminated fluid comprising passing at least a portion of the fluid through the porous membrane of claim 1 and recovering a contaminant depleted fluid.

31. The process of claim 30, wherein said contaminated fluid is corrosive.

32. A process for recovering a material from a fluid comprising contacting said fluid with a membrane of claim 1 so as to retain at least a portion of the material on the membrane.

33. The membrane of claim 13, which includes a porous support.

34. The membrane of claim 33, wherein the porous support comprises polytetrafluoroethylene.

17. A process for preparing an integral porous membrane comprising an amorphous halopolymer, the process comprising:

(a) providing a solution of said halopolymer the halopolymer comprising a fluorocopolymer including tetrafluoroethylene and a perfluoro-1,3-dioxide;

(b) shaping the solution to form a pre-membrane; and

(c) causing phase inversion of the pre-membrane to obtain the integral porous membrane, wherein the membrane has an average pore size of about 0.1 μ

m to about 10 μ

m.

18. The process of claim 17, wherein said perfluoro-1,3-dioxole is perfluoro-2,2-dimethyl-1,3-dioxole.

19. The process of claim 17, wherein said copolymer includes from about 10% to about 40% by mole of tetrafluoroethylene and from about 90% to about 60% by mole of perfluoro-2,2-methyl-1,3-dioxole.

20. The process of claim 17, wherein said copolymer includes from about 30% to about 40% by mole of tetrafluoroethylene and from about 70% to about 60% by mole of perfluoro-2,2-dimethyl-1,3-dioxole.

21. The process of claim 17, wherein said copolymer includes about 35% by mole of tetrafluoroethylene and about 65% by mole of perfluoro-2,2-dimethyl-1,3-dioxole.

22. The process of claim 17, wherein said copolymer includes about 15% by mole of tetrafluoroethylene and about 85% by mole of perfluoro-2,2-dimethyl-1,3-dioxole.

23. The process of claim 17, wherein said solution contains a fluorocarbon solvent.

24. The process of claim 17, wherein the solution further includes a nonsolvent for the halopolymer.

25. The process of claim 17, wherein said phase inversion is caused by treating the pre-membrane with a nonsolvent.

26. The process of claim 17, wherein said phase inversion is caused by changing the temperature of the pre-membrane.

27. A membrane prepared by the process of claim 17.