Fibrous web for processing a fluid

• US 5,846,438 A
• Filed: 01/20/1995
• Issued: 12/08/1998
• Est. Priority Date: 07/28/1994
• Status: Expired due to Term

• Current Assignee: Pall Corporation (Danaher Corporation)
• Original Assignee: Pall Corporation (Danaher Corporation)
• Inventors: Pall, David B., Manteuffel, Richard L.
• Primary Examiner(s): Bell, James J.
• Application Number:
  US08/376,190
• Time in Patent Office: 1,418 Days
• Field of Search: 210/767, 210/483, 210/488, 210/491, 210/496, 210/508, 210/806, 428/903
• US Class Current: 210/767
• CPC Class Codes: B01D 2239/0421 Rendering the filter material hydrophilic
• CPC Class Codes: B01D 2239/0471 Surface coating material
• CPC Class Codes: B01D 2239/06 Filter cloth, e.g. knitted, woven non-woven; self-supported material
• CPC Class Codes: B01D 2239/0622 Melt-blown
• CPC Class Codes: B01D 2239/064 The fibres being mixed
• CPC Class Codes: B01D 2239/065 More than one layer present in the filtering material apparatus incorporating such gas filtering material B01D2275/10
• CPC Class Codes: B01D 2239/0681 The layers being joined by gluing
• CPC Class Codes: B01D 2239/10 Filtering material manufacturing
• CPC Class Codes: B01D 2239/1233 Fibre diameter
• CPC Class Codes: B01D 2239/1291 Other parameters
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: B01D 61/18 Apparatus therefor
• CPC Class Codes: B01D 69/12 Composite membranes; Ultra-thin membranes
• CPC Class Codes: B01D 71/34 Polyvinylidene fluoride
• CPC Class Codes: B01L 2200/12 Specific details about manufacturing devices
• CPC Class Codes: B01L 2300/0812 Bands; Tapes
• CPC Class Codes: B01L 2300/0825 Test strips
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2300/12 Specific details about materials
• CPC Class Codes: B01L 2400/0406 capillary forces
• CPC Class Codes: B01L 3/5023 : with a sample being transported to, and subsequently stored in an absorbent for analysis
• CPC Class Codes: D01D 5/0985 : by means of a flowing gas (e.g. melt-blowing)
• CPC Class Codes: D04H 1/43838 : Ultrafine fibres, e.g. microfibres
• CPC Class Codes: D04H 1/56 : in association with fibre formation, e.g. immediately following extrusion of staple fibres
• CPC Class Codes: Y10S 428/903 : Microfiber, less than 100 micron diameter
• CPC Class Codes: Y10T 428/1307 : Bag or tubular film [e.g., pouch, flexible food casing, envelope, etc.]
• CPC Class Codes: Y10T 428/249953 : Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249978 : Voids specified as micro
• CPC Class Codes: Y10T 428/24998 : Composite has more than two layers
• CPC Class Codes: Y10T 428/249982 : With component specified as adhesive or bonding agent
• CPC Class Codes: Y10T 428/249987 : With nonvoid component of specified composition
• CPC Class Codes: Y10T 428/249995 : Constituent is in liquid form
• CPC Class Codes: Y10T 442/626 : Microfiber is synthetic polymer
• CPC Class Codes: Y10T 442/674 : Nonwoven fabric with a preformed polymeric film or sheet
• CPC Class Codes: Y10T 442/676 : Vinyl polymer or copolymer sheet or film [e.g., polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, etc.]
• CPC Class Codes: Y10T 442/68 : Melt-blown nonwoven fabric

Abstract

Melt-blown fibrous webs having a uniform structure for use in processing biological fluids are disclosed.

Claims

1. A device for processing a biological fluid comprising at least one melt-blown fibrous web, said device having a region for receiving a biological fluid containing an analyte and other substances, and a region into which said analyte flows without at least a portion of said other substances, wherein said web comprises fibers such that 90% of said fibers have a diameter ranging from a minimum fiber diameter to a maximum fiber diameter which is no more than about three times the minimum fiber diameter, and wherein said web has a critical wetting surface tension (CWST) of at least about 65 dynes/cm.

2. The device of claim 1, wherein said fibers comprise at least one of polybutylene terephthalate, polyethylene terephthalate, and nylon.

3. The device of claim 1, having at least a first surface for contacting the biological fluid, and a second surface through which said analyte flows without at least a portion of said other substances.

4. The device of claim 3, wherein said device further comprises a porous medium having at least an upstream surface and a downstream surface, wherein at least a portion of said upstream surface of said porous medium is in fluid communication with said second surface of said web, and wherein said porous medium allows for said analyte to be captured thereby and prevents at least some of said other substances from passing therein.

5. The device of claim 4, wherein said porous medium has a cantilevered region which extends beyond said web.

6. The device of claim 4, wherein said porous medium comprises a porous membrane.

7. The device of claim 6, wherein said porous membrane comprises an isotropic, skinless, polyvinylidene fluoride membrane.

8. The device of claim 7, wherein said porous membrane has a titer reduction of at least about 10⁸ against T₁ bacteriophage.

9. The device of claim 8, wherein said porous membrane has a K_UF of at least about 15 psi when tested using liquid pairs having an interfacial tension of about 4 dynes/cm.

10. The device of claim 6, wherein said porous membrane comprises a hydrophilic nylon membrane.

11. The device of claim 10, wherein said porous membrane has an absolute pore size of about 2 μ

m or less.

12. The device of claim 6, wherein said device further comprises at least one nonporous medium which is in contact with at least one surface of said porous medium.

13. The device of claim 5, wherein said web contains a compressed portion adjacent to said cantilevered region of said porous medium which prevents at least some of said other substances from passing therethrough to said cantilevered region.

14. The device of claim 3, wherein said device further comprises at least one nonporous medium which is in contact with said surface of said web.

15. The device of claim 4, wherein said device further comprises a second porous medium interposed between said web and the first porous medium.

16. The device of claim 15, wherein said second porous medium comprises a second melt-blown fibrous non-woven web.

17. The device of claim 4, wherein said device further comprises a second porous medium having an upstream surface and a downstream surface, and said upstream surface of said second porous medium is in fluid communication with said first porous medium.

18. The device of claim 17, wherein said first porous medium comprises a porous membrane.

19. The device of claim 18, wherein said porous membrane comprises an isotropic, skinless, polyvinylidene fluoride membrane.

20. The device of claim 19, wherein said porous membrane has a titer reduction of at least about 10⁸ against T₁ bacteriophage.

21. The device of claim 20, wherein said porous membrane has a K_UF of at least about 15 psi when tested using liquid pairs having an interfacial tension of about 4 dynes/cm.

22. The device of claim 18, wherein said second porous medium comprises a melt-blown fibrous non-woven web.

23. The device of claim 22, wherein said device further comprises one or more nonporous media adhered to said device so as to reduce evaporation of said biological sample.

24. The device of claim 22, wherein the second porous medium has a higher CWST than the melt-blown fibrous web receiving the biological fluid sample.

25. The device of claim 1, wherein the web has an average fiber diameter of less than about 4 μ

m .

26. The device of claim 25, wherein the web has a voids volume in the range of about 70% to about 95%.

27. The device of claim 26, wherein the voids volume is in the range of about 75% to about 85%.

28. The device of claim 27, wherein the voids volume is in the range of about 78% to about 81%.

29. The device of claim 1, wherein said web has a CWST of at least about 70 dynes/cm.

30. The device of claim 29, wherein said web has a CWST of at least about 90 dynes/cm.

31. The device of claim 30, wherein said web has a CWST of at least about 110 dynes/cm.

32. The device of claim 1, wherein the web has a basis weight of at least about 2 g/ft².

33. The device of claim 32, wherein the web has a basis weight of at least about 4 g/ft².

34. The device of claim 33, wherein the web has a basis weight in the range of from about 5 to about 8 g/ft².

35. The device of claim 1, wherein said device further comprises one or more nonporous media adhered to said device so as to reduce evaporation of said biological sample.

36. The device of claim 25, wherein the web has an average fiber diameter of less than about 2 μ

m .

48. The device of claim 1, wherein the web includes a region into which said analyte flows without at least a portion of said other substances.

49. The device of claim 1, wherein said device further comprises a porous medium having at least an upstream surface and a downstream surface, wherein at least a portion of said upstream surface of said porous medium is in fluid communication with said web, and wherein said porous medium allows for said analyte to be captured thereby and prevents at least some of said other substances from passing therein.

50. The device of claim 49, wherein said porous medium comprises a microporous membrane.

51. A method of processing a biological fluid comprising contacting said biological fluid receiving region of said device of claim 1 with a biological fluid containing an analyte and other substances.

52. The method of claim 51, comprising contacting the region with about 20 μ

L of blood or less.

53. The method of claim 52, comprising contacting the region with about 10 μ

L of blood.

54. The method of claim 53, wherein said biological fluid is blood or a blood product, and said analyte is plasma.

55. The method of claim 51, wherein said biological fluid is blood or a blood product, and said analyte is a virus.

56. The method of claim 51, wherein said biological fluid is blood or a blood product, and said analyte is glucose.

57. The method of claim 51, wherein said biological fluid is plasma, and said analyte is a virus.

37. A device for processing a biological fluid comprising a melt-blown fibrous web, wherein said web comprises fibers such that 90% of said fibers have a diameter ranging from a minimum fiber diameter to a maximum fiber diameter which is no more than about three times the minimum fiber diameter, and wherein said web has a critical wetting surface tension (CWST) of at least about 76 dynes/cm, and wherein said web has a voids volume in the range from about 75% to about 85%.

38. The device of claim 37, wherein the web includes a basis weight in the range of from about 3 to about 7 g/ft².

39. The device of claim 37, wherein said web includes a voids volume in the range of about 78% to about 81%.

40. The device of claim 39, wherein said web has a CWST of at least about 95 dynes/cm.

41. The device of claim 40, wherein said web has a CWST of at least about 100 dynes/cm.

42. A device for processing a biological fluid comprising a melt-blown fibrous web, wherein said web comprises fibers such that 90% of said fibers have a diameter ranging from a minimum fiber diameter to a maximum fiber diameter which is no more than about three times the minimum fiber diameter, and wherein said web has a critical wetting surface tension (CWST) of at least about 98 dynes/cm, and wherein said fibers have an average fiber diameter of about 2 μ

m or less, wherein said web has a voids volume in the range from about 75% to about 85%.

43. The device of claim 42, wherein said web has a basis weight of at least about 3 g/ft².

44. The device of claim 43, wherein said web has a CWST of at least about 105 dynes/cm, and includes a voids volume in the range of from about 77% to about 84%.

45. The device of claim 44, wherein said web has a basis weight of at least about 5 g/ft².

46. The device of claim 45, wherein said fibers have an average fiber diameter of about 1.8 μ

m or less.

47. A device for processing a biological fluid comprising at least a first melt-blown fibrous wed and a second melt-blow fibrous web, said first web having a region for receiving a biological fluid containing an analyte and other substances, and said second melt-blown fibrous web having a region into which said analyte flows without at least a portion of said other substances, wherein said first and second webs each comprise fibers such that 90% of said fibers have a diameter ranging from a minimum fiber diameter to a maximum fiber diameter which is no more than about three times the minimum fiber diameter, and wherein said first and second webs each have critical wetting surface tension (CWST) of at least about 65 dynes/cm.

58. A method for processing a biological fluid comprising:

contacting a melt-blown fibrous web with the biological fluid, wherein said web comprises fibers such that 90% of said fibers have a diameter ranging from a minimum fiber diameter to a maximum fiber diameter which is no more than about three times the minimum fiber diameter, and wherein said web has a critical wetting surface tension (CWST) of at least about 65 dynes/cm.

59. The method of claim 58, wherein contacting the web with a biological fluid comprises contacting the web with blood, and separating plasma from the blood.

60. The method of claim 58, wherein contacting the web with a biological fluid comprises contacting the web with blood, and passing plasma through the web ahead of the red cells in the blood.

61. The method of claim 59, further comprising passing the plasma from the web into at least one porous medium.

62. The method of claim 61 wherein the porous medium comprises at least one of an additional melt-blown web, and a microporous membrane.

63. The method of claim 58, wherein the biological fluid includes at least one of glucose;

cholesterol;

at least one serum enzyme;

at least one lipid; and

at least one drug.