Composite Membrane and Moisture Adjustment Module Using Same

• US 20090324929A1
• Filed: 09/26/2008
• Published: 12/31/2009
• Est. Priority Date: 06/25/2008
• Status: Abandoned Application

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Inventors: Johnson, Wiliam B., Yamakawa, Keiichi, Murthy, Mahesh, Berta, Thomas
• Application Number:
  US12/239,037
• Publication Number:
  US 20090324929A1
• Time in Patent Office: Days
• US Class Current: 428/315.9
• CPC Class Codes: B01D 2313/14 Specific spacers
• CPC Class Codes: B01D 2319/06 Use of membranes of different materials or properties within one module
• CPC Class Codes: B01D 2323/08 Specific temperatures applied
• CPC Class Codes: B01D 2323/081 Heating
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 2325/02 Details relating to pores or porosity of the membranes
• CPC Class Codes: B01D 2325/02833 more than 10 and up to 100 nm
• CPC Class Codes: B01D 2325/04 Characteristic thickness
• CPC Class Codes: B01D 2325/20 Specific permeability or cut-off range
• CPC Class Codes: B01D 2325/36 Hydrophilic membranes
• CPC Class Codes: B01D 2325/38 Hydrophobic membranes
• CPC Class Codes: B01D 2325/42 Ion-exchange membranes
• CPC Class Codes: B01D 63/082 comprising a stack of flat membranes
• CPC Class Codes: B01D 67/0013 Casting processes
• CPC Class Codes: B01D 69/10 Supported membranes; Membrane supports
• CPC Class Codes: B01D 69/12 Composite membranes; Ultra-thin membranes
• CPC Class Codes: B01D 69/1213 Laminated layers
• CPC Class Codes: B01D 71/32 containing fluorine atoms
• CPC Class Codes: B01D 71/38 Polyalkenylalcohols; Polyalkenylesters; Polyalkenylethers; Polyalkenylaldehydes; Polyalkenylketones; Polyalkenylacetals; Polyalkenylketals
• CPC Class Codes: B01D 71/381 Polyvinylalcohol
• CPC Class Codes: H01M 2008/1095 : Fuel cells with polymeric electrolytes
• CPC Class Codes: H01M 2300/0082 : Organic polymers
• CPC Class Codes: H01M 8/04149 : by diffusion, e.g. making use of membranes
• CPC Class Codes: H01M 8/1018 : Polymeric electrolyte materials
• CPC Class Codes: H01M 8/1023 : having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: H01M 8/1039 : halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: H01M 8/1053 : consisting of layers of polymers with at least one layer being ionically conductive
• CPC Class Codes: H01M 8/106 : characterised by the chemical composition of the porous support
• CPC Class Codes: H01M 8/1062 : characterised by the physical properties of the porous support, e.g. its porosity or thickness
• CPC Class Codes: H01M 8/1067 : characterised by their physical properties, e.g. porosity, ionic conductivity or thickness
• CPC Class Codes: H01M 8/1081 : starting from solutions, dispersions or slurries exclusively of polymers
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 156/10 : Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 428/24998 : Composite has more than two layers
• CPC Class Codes: Y10T 428/249991 : Synthetic resin or natural rubbers

Abstract

A composite membrane and moisture adjustment module using the same is disclosed. The composite membrane includes a moisture-permeable resin layer interposed between porous membranes that constitute a pair; and the mean thickness of the moisture-permeable resin layer is 5 μm or less.

Claims

1. A composite membrane wherein:

a moisture-permeable resin layer is interposed between porous membranes that constitute a pair; and

the mean thickness of the moisture-permeable resin layer is 5 μ

m or less.

2. The composite membrane according to claim 1, wherein said moisture-permeable resin comprises a water-resistant, moisture-permeable resin.

3. The composite membrane according to claim 2, wherein the degree of swelling of said water-resistant, moisture-permeable resin, is 20 times or less.

4. The composite membrane according to claim 2 wherein said water-resistant, moisture-permeable resin comprises a crosslinked polyvinyl alcohol.

5. The composite membrane according to claim 2, wherein said water-resistant, moisture-permeable resin comprises an ion-exchange fluororesin.

6. The composite membrane according to claim 5, wherein said water-resistant, moisture-permeable resin comprises a perfluorosulfonic acid polymer.

7. The composite membrane according to claim 3 wherein said water-resistant, moisture-permeable resin comprises a crosslinked polyvinyl alcohol.

8. The composite membrane according to claim 1 wherein at least part of said moisture-permeable resin is embedded in the porous membrane.

9. The composite membrane according claim 4 wherein at least part of said moisture-permeable resin is embedded in the porous membrane.

10. The composite membrane according claim 6 wherein at least part of said moisture-permeable resin is embedded in the porous membrane.

11. The composite membrane according claims 1 wherein:

the mean pore diameter of the said porous membranes is 0.05 μ

m or greater; and

the maximum pore diameter is 15 μ

m or less.

12. The composite membrane according claims 4 wherein:

the mean pore diameter of said porous membranes is 0.05 μ

m or greater; and

the maximum pore diameter is 15 μ

m or less.

13. The composite membrane according claims 6 wherein:

the mean pore diameter of said porous membranes is 0.05 μ

m or greater; and

the maximum pore diameter is 15 μ

m or less.

14. The composite membrane according to claim 1 wherein the void content of the said porous membranes is 40% or greater.

15. The composite membrane according to claim 4 wherein the void content of the said porous membranes is 40% or greater.

16. The composite membrane according to claim 6 wherein the void content of the said porous membranes is 40% or greater.

17. The composite membrane according to claim 1 wherein the mean thickness of said porous membranes is 1 to 200 μ

m.

18. The composite membrane according to claim 4 wherein the mean thickness of said porous membranes is 1 to 200 μ

m.

19. The composite membrane according to claim 6 wherein the mean thickness of said porous membranes is 1 to 200 μ

m.

20. The composite membrane according to any of claims 1 wherein at least one of said porous membranes comprises a expanded polytetrafluoroethylene membrane.

21. The composite membrane according to any of claims 4 wherein at least one of said porous membranes comprises a expanded polytetrafluoroethylene membrane.

22. The composite membrane according to any of claims 6 wherein at least one of said porous membranes comprises a expanded polytetrafluoroethylene membrane.

23. The composite membrane according to claims 1 wherein a gas-permeable reinforcing element is layered on at least one of the porous membranes.

24. The composite membrane according to claims 4 wherein a gas-permeable reinforcing element is layered on at least one of the porous membranes.

25. The composite membrane according to claims 6 wherein a gas-permeable reinforcing element is layered on at least one of the porous membranes.

26. A moisture adjustment module, obtained by superposing the composite membrane of claims 1 while open spaces are left therebetween.

27. A moisture adjustment module, obtained by superposing the composite membrane of claims 4 while open spaces are left therebetween.

28. A moisture adjustment module, obtained by superposing the composite membrane of claim 6 while open spaces are left therebetween.

29. A composite membrane wherein an air-impermeable layer comprising a perfluorosulfonic acid polymer is interposed between a first and second micro-porous membrane.

30. A composite membrane of claim 29 wherein at least one of said first and second micro-porous membranes is hydrophobic.

31. A composite membrane of claim 29 wherein at least one of said first and second micro-porous membranes is hydrophilic.

32. A composite membrane of claim 29 wherein said perfluorosulfonic acid polymer further comprises a reinforcement.

33. A composite membrane of claim 29 wherein said air impermeable layer has a mean thickness less than 20 um.

34. The composite membrane according to claim 29 wherein at least part of said impermeable layer is embedded in the micro-porous membrane.

35. The composite membrane according to claim 29 wherein at least one of said first and second micro-porous layers comprises expanded polytetrafluoroethylene.

36. A composite membrane of claim 32 wherein said reinforcement comprises particulates.

37. A composite membrane of claim 32 wherein said reinforcement comprises a third micro-porous membrane.

38. A composite membrane of claim 37 wherein said third micro-porous membrane comprises expanded polytetrafluoroethylene.

39. A composite membrane of claim 29 wherein at least one of said first and second micro-porous membranes has a reinforcing member attached to it.

40. A moisture-permselective membrane of claim 39 wherein said reinforcing member is a non-woven material.

41. A moisture-permselective membrane of claim 39 wherein said reinforcing member is a woven material.

42. A moisture adjustment module, obtained by superposing the composite membrane of claims 29 while open spaces are left therebetween.

43. A moisture adjustment module, obtained by superposing the composite membrane of claims 32 while open spaces are left therebetween.

44. A method of preparing a composite membrane comprising the steps of

a. Casting a solution comprising a moisture permselective resin on a first micro-porous membrane to form a film on the surface of said micro-porous membrane;

b. Stretching a second micro-porous membrane over said film before it is dry to form a composite structure;

c. Drying said composite structure to remove residual liquid from said solution.

45. A method of claim 44 wherein said film is between 0.5 and 10 um thick after step c.

46. A method of claim 44 wherein an additional step of heat-treating said composite membrane after step (c) is performed.

47. The method of claim 44 wherein a reinforcing member is laminated to at least one side of said composite membrane after step c.

48. A method of claim 46 wherein said heat treatment comprises holding said composite membrane at a temperature between 100 and 180 C for a period of time between 1 and 15 minutes.

49. A method of preparing a composite membrane comprising the steps of:

a. Preparing a membrane having two sides, said membrane comprising a moisture permselective resin;

b. Laminating one side of said membrane to a first micro-porous membrane;

c. Laminating a second micro-porous membrane to the second side of said membrane.

50. The method of claim 49 wherein at least one of the first micro-porous membrane and the second micro-porous membrane comprise expanded polytetrafluoroethylene.

51. The method of claim 49 wherein said membrane comprising moisture permselective resin further comprises expanded polytetrafluoroethylene.

52. The method of claim 49 wherein said membrane comprising moisture permselective resin comprises a perfluorosulfonic acid polymer.

53. The method of claim 49 wherein a reinforcing member is laminated to at least one side of said composite membrane after step c.

54. The method of claim 49 wherein said membrane comprising moisture permselective resin in step (a) has a mean thickness of less than 15 μ

m.

55. The method of claim 49 wherein said membrane comprising moisture permselective resin in step (a) has a mean thickness of less than 6 μ

m.

56. A composite membrane wherein an air-impermeable layer comprising an ionomeric polymer is interposed between a first and second micro-porous membrane.

57. A composite membrane of claim 56 wherein at least one of said first and second micro-porous membranes is hydrophobic.

58. A composite membrane of claim 56 wherein at least one of said first and second micro-porous membranes is hydrophilic.

59. A composite membrane of claim 56 wherein said perfluorosulfonic acid polymer further comprises a reinforcement.

60. A composite membrane of claim 56 wherein said air impermeable layer has a mean thickness less than 20 um.

61. The composite membrane according to claim 56 wherein at least part of said impermeable layer is embedded in the micro-porous membrane.

62. The composite membrane according to claim 56 wherein at least one of said first and second micro-porous layers comprises expanded polytetrafluoroethylene.

63. A composite membrane of claim 59 wherein said reinforcement comprises particulates.

64. A composite membrane of claim 59 wherein said reinforcement comprises a third micro-porous membrane.

65. A composite membrane of claim 64 wherein said third micro-porous membrane comprises expanded polytetrafluoroethylene.

66. A composite membrane of claim 56 wherein at least one of said first and second micro-porous membranes has a reinforcing member attached to it.

67. A moisture-permselective membrane of claim 66 wherein said reinforcing member is a non-woven material.

68. A moisture-permselective membrane of claim 66 wherein said reinforcing member is a woven material.

69. A moisture adjustment module, obtained by superposing the composite membrane of claims 56 while open spaces are left therebetween.

70. A moisture adjustment module, obtained by superposing the composite membrane of claims 59 while open spaces are left therebetween.