Reticulated absorbent composite

• US 6,969,781 B2
• Filed: 08/27/1998
• Issued: 11/29/2005
• Est. Priority Date: 05/13/1997
• Status: Expired due to Fees

• Current Assignee: National Institute for Strategic Technology Acquisition and Commercialization
• Original Assignee: Weyerhaeuser Company (Weyerhauser)
• Inventors: Graef, Peter A., Howard, Fred B.
• Primary Examiner(s): Calvert, John J.
• Assistant Examiner(s): KIDWELL, MICHELE M
• Application Number:
  US09/141,152
• Publication Number:
  US 20030009141A1
• Time in Patent Office: 2,651 Days
• Field of Search: 604/368, 604/358, 604/367, 604/385.01
• US Class Current: 604/367
• CPC Class Codes: A61F 13/5323 having absorbent material located in discrete regions, e.g. pockets
• CPC Class Codes: A61F 13/534 having an inhomogeneous composition through the thickness of the pad A61F13/538, A61F13/539 take precedence; homogeneous cores with tissue wrapping A61F13/53
• CPC Class Codes: A61F 13/53747 the layer is facing the topsheet layer is part of the topsheet A61F13/511
• CPC Class Codes: A61F 13/5376 characterised by the performance of the layer, e.g. acquisition rate, distribution time, transfer time
• CPC Class Codes: A61F 2013/15406 Basis weight
• CPC Class Codes: A61F 2013/15422 Density
• CPC Class Codes: A61F 2013/530051 being made in cross-linked cellulosic fibres
• CPC Class Codes: A61F 2013/53051 being only in particular parts or specially arranged
• CPC Class Codes: A61F 2013/53765 characterized by its geometry

Abstract

An absorbent composite (10) having a fibrous matrix that includes absorbent material is disclosed. The fibrous matrix defines voids (14) and passages between the voids, which are distributed throughout the composite. Absorbent material (18) is located within some of the voids (14). Absorbent material located in these voids is expandable into the void. In a preferred embodiment, the composite'"'"'s fibrous matrix includes resilient and matrix fibers (16). The composite optionally includes a wet strength agent.

Claims

1. An absorbent composite, comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix comprises bonded cellulosic fibers, wherein the fibrous matrix includes voids and passages between voids within the matrix;

wherein the absorbent material is located within some of the voids; and

wherein the absorbent material located within the voids is expandable further into or within the voids.

2. The composite of claim 1 wherein the fibrous matrix comprises fibers selected from the group consisting of resilient fibers, matrix fibers, and mixtures thereof.

3. The composite of claim 1 further comprising a wet strength agent.

4. The composite of claim 2 wherein the resilient fibers are selected from the group consisting of chemically stiffened fibers, anfractuous fibers, chemithermomechanical pulp fiber, prehydrolyzed kraft pulp fibers, synthetic fibers, and mixtures thereof.

5. The composite of claim 4 wherein the chemically stiffened fibers comprise crosslinked cellulosic fibers.

6. The composite of claim 5 wherein the crosslinked cellulosic fibers are crosslinked with a crosslinking agent selected from the group consisting of urea-based and polycarboxylic acid crosslinking agents.

7. The composite of claim 4 wherein the synthetic fibers are selected from the group consisting of polyolefin, polyester, and polyamide fibers.

8. The composite of claim 7 wherein the polyester fibers are polyethylene terephthalate fibers.

9. The composite of claim 1 wherein the matrix fibers comprise cellulosic fibers.

10. The composite of claim 9 wherein the cellulosic fibers comprise fibers selected from the group consisting of wood pulp fibers, cotton linters, cotton fibers, hemp fibers, and mixtures thereof.

11. The composite of claim 2 wherein the resilient fibers are present in the composite in an amount from about 5 to about 60 percent by weight of the total composite.

12. The composite of claim 2 wherein the matrix fibers are present in the composite in an amount from about 10 to about 60 percent by weight of the total composite.

13. The composite of claim 1 wherein the absorbent material is a superabsorbent material.

14. The composite of claim 13 wherein the superabsorbent material is selected from the group consisting of superabsorbent particles and superabsorbent fibers.

15. The composite of claim 1 wherein the absorbent material is present in an amount from about 5 to about 60 percent by weight of the total composite.

16. The composite of claim 1 wherein the absorbent material is present in about 40 percent by weight of the total composite.

17. The composite of claim 1 wherein the absorbent material absorbs from about 5 to about 100 times its weight in 0.9 percent saline solution.

18. The composite of claim 3 wherein the wet strength agent is a resin selected from the group consisting of polyamide-epichlorohydrin and polyacrylamide resins.

19. The composite of claim 3 wherein the wet strength agent is present in the composite in an amount from about 0.01 to about 2 percent by weight of the total composite.

20. The composite of claim 1 having a basis weight of from about 50 to about 1000 g/m².

21. The composite of claim 1 having a density of from about 0.02 to about 0.7 g/cm³.

22. The composite of claim 1 wherein the composite is formed by a wet-laid process.

23. The composite of claim 1 wherein the composite is formed by a foam process.

24. The composite of claim 5 wherein the crosslinked cellulosic fibers are present in about 12 percent by weight based on the total weight of the composite.

25. The composite of claim 10 wherein the wood pulp fibers are present in about 48 percent by weight based on the total weight of the composite.

26. The composite of claim 13 wherein the absorbent material is present in about 40 percent by weight based on the total weight of the composite.

27. The composite of claim 18 wherein the polyamide-epichlorohydrin resin is present in about 0.5 percent by weight based on the total weight of the composite.

28. An absorbent article comprising the composite of claim 1.

29. The absorbent article of claim 28 wherein the article is a diaper.

30. The absorbent article of claim 28 wherein the article is a feminine care product.

31. The absorbent article of claim 28 wherein the article is an adult incontinence product.

32. An absorbent article comprising an absorbent composite comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix comprises bonded cellulosic fibers, wherein the fibrous matrix includes voids and passages between voids within the matrix;

wherein the absorbent material is located within some of the voids; and

wherein the absorbent material located within the voids is expandable further into or within the voids.

38. The absorbent article of claim 32 wherein the article is selected from the group consisting of a diaper and an incontinence product.

39. The absorbent articles of claim 32 further comprising leg gathers.

33. An absorbent article comprising:

liquid pervious topsheet;

a storage layer comprising an absorbent composite comprising absorbent material dispersed within a fibrous matrix;

wherein the fibrous matrix comprises bonded cellulosic fibers, wherein the fibrous matrix includes voids and passages between voids within the matrix;

wherein the absorbent material is located within some of the voids; and

wherein the absorbent material located within the voids is expandable further into or within the voids; and

a liquid impervious back sheet.

37. The absorbent article of claim 33 wherein the article is a feminine care product.

34. An absorbent article comprising:

a liquid pervious topsheet;

an acquisition layer for rapidly acquiring and distributing liquid;

a storage layer comprising an absorbent composite comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix comprises bonded cellulosic fibers, wherein the fibrous matrix includes voids and passages between voids within the matrix;

wherein the absorbent material is located within some of the voids; and

wherein the absorbent material located within the voids is expandable further into or within the voids; and

a liquid impervious back sheet.

35. An absorbent article comprising:

a liquid pervious topsheet;

an acquisition layer for rapidly acquiring and distributing liquid;

a storage layer comprising an absorbent composite comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix comprises bonded cellulosic fibers, wherein the fibrous matrix includes voids and passages between voids within the matrix;

wherein the absorbent material is located within some of the voids; and

wherein the absorbent material located within the voids is expandable further into or within the voids;

an intermediate layer interposed between the acquisition layer and the storage layer; and

a liquid impervious back sheet.

36. The absorbent article of claim 35 wherein the intermediate layer is selected from the group consisting of a liquid pervious tissue and a distribution layer.

40. An absorbent article comprising:

a liquid pervious topsheet;

an acquisition layer for acquiring and distributing liquid;

a storage layer; and

a liquid impervious back sheet;

wherein the acquisition layer comprises an absorbent composite comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix comprises bonded cellulosic fibers, wherein the fibrous matrix includes voids and passages between voids within the matrix;

wherein the absorbent material is located within some of the voids; and

wherein the absorbent material located within the voids is expandable further into or within the voids.

41. The absorbent article of claim 40 wherein the acquisition layer has a top surface area less than the top surface area of the storage core.

42. The absorbent article of claim 40 wherein the acquisition layer has a top surface area about equal to the top surface area of the storage core.

43. The absorbent article of claim 40 wherein the storage layer comprises an absorbent composite comprising a fibrous matrix and absorbent material,

wherein the fibrous matrix defines voids and passages between voids distributed substantially throughout the matrix;

wherein the absorbent material is located within some of the voids; and

wherein the absorbent material located within the voids is expandable into the voids.

51. The composite of claim 40, wherein the fibrous matrix comprises of synthetic fibers.

52. The composite of claim 51, wherein the synthetic fibers comprise from about 20 to 90 weight percent of the total weight of the composite.

53. The composite of claim 40, wherein the fibrous matrix comprises stiffened cellulose fibers.

54. The composite of claim 40, wherein the composite has a density of from about 0.02 to about 0.7 g/cm³.

55. The composite of claim 40, wherein the composite has a density of from about 0.04 to about 0.3 g/cm³.

56. The composite of claim 40, wherein the composite has a density of from about 0.1 to about 0.5 g/cm³.

57. The composite of claim 40, wherein the composite has a dry tensile strength of from about 0.15 to 0.66 Nm/g.

58. The composite of claim 40, wherein the composite comprises from about 50 to about 70 weight percent of fibers based on the total weight of the composite.

44. An absorbent composite, comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix includes voids and passages between voids distributed substantially throughout the matrix;

wherein absorbent material is located within some of the voids;

wherein the absorbent material is expandable further into or within the voids; and

wherein the fibrous matrix comprises from about 20 to about 90 weight percent of fibers, based on the total weight of the composite.

45. The composite of claim 44, wherein the absorbent material is present in an amount from about 5 to about 60 percent by weight of the composite.

46. The composite of claim 44, wherein the absorbent material is present in an amount from about 30 to about 50 percent by weight of the composite.

47. The composite of claim 44, wherein the absorbent composite further comprises a wet strength agent.

48. The composite of claim 47, wherein the wet strength agent is present in an amount from about 0.01 to about 2 weight percent based on the total weight of the composite.

49. The composite of claim 47, wherein the wet strength agent is present in an amount from about 0.1 to about 1 weight percent based on the total weight of the composite.

50. The composite of claim 47, wherein the wet strength agent is present in an amount from about 0.3 to about 0.7 weight percent based on the total weight of the composite.

59. An absorbent article, comprising an absorbent composite comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix includes voids and passages between voids distributed substantially throughout the matrix;

wherein the absorbent material is located within some of the voids;

wherein the absorbent material located within the voids is expandable into or the voids, and

wherein the fibrous matrix comprises from about 20 to about 90 percent by weight fibers based on the total weight of the matrix.

60. An absorbent article, comprising:

liquid pervious topsheet;

a liquid impervious back sheet; and

a storage layer intermediate the topsheet and backsheet, the storage layer comprising an absorbent composite comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix includes voids and passages between voids distributed substantially throughout the matrix;

wherein the absorbent material is located within some of the voids;

wherein the absorbent material located within the voids is expandable further into or within the voids, and

wherein the fibrous matrix comprises from about 20 to about 90 percent by weight fibers based on the total weight of the composite.

61. An absorbent article, comprising:

a liquid pervious topsheet;

a liquid impervious back sheet;

an acquisition layer for rapidly acquiring and distributing liquid; and

a storage layer intermediate the topsheet and backsheet, the storage layer comprising an absorbent composite comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix includes voids and passages between voids distributed substantially throughout the matrix;

wherein the absorbent material is located within some of the voids;

wherein the absorbent material located within the voids is expandable further into or within the voids, and

wherein the fibrous matrix comprises from about 20 to about 90 percent by weight fibers based on the total weight of the composite.

62. An absorbent article, comprising:

a liquid pervious topsheet;

a liquid impervious backsheet;

an acquisition layer for rapidly acquiring and distributing liquid;

an intermediate layer interposed between the acquisition layer and the storage layer; and

a storage layer intermediate the topsheet and backsheet, the storage layer comprising an absorbent composite comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix includes voids and passages between voids distributed substantially throughout the matrix;

wherein the absorbent material is located within some of the voids;

wherein the absorbent material located within the voids is expandable further into or within the voids, and

wherein the fibrous matrix comprises from about 20 to about 90 percent by weight fibers based on the total weight of the composite.

63. An absorbent article, comprising:

a liquid pervious topsheet;

an acquisition layer for acquiring and distributing liquid;

a storage layer; and

a liquid impervious back sheet;

wherein the acquisition layer comprises an absorbent composite comprising absorbent material dispersed within a fibrous matrix,

wherein the fibrous matrix includes voids and passages between voids distributed substantially throughout the matrix;

wherein the absorbent material is located within some of the voids;

wherein the absorbent material located within the voids is expandable further into or within the voids, and

wherein the fibrous matrix comprises from about 20 to about 90 percent by weight fibers based on the total weight of the composite.

64. An absorbent composite having absorbent material dispersed within a fibrous matrix, wherein the fibrous matrix comprises bonded cellulosic fibers;

wherein the fibrous matrix includes voids and passages between voids distributed substantially throughout the matrix;

wherein absorbent material is located within the voids; and

wherein the voids are formed by drying absorbent material swollen with water during the formation of the composite.

65. An absorbent composite having absorbent material dispersed within a fibrous matrix, wherein the fibrous matrix comprises bonded cellulosic fibers, the composite being formed by the process comprising:

(a) contacting a foraminous support with a combination of cellulosic fibers, water, and absorbent material swellable in water to provide a wet composite, wherein the wet composite comprises cellulosic fibers, water, and absorbent material swollen with water; and

(b) drying the wet composite, wherein drying comprises removing at least a portion of the water from the swollen absorbent material to provide an absorbent composite having absorbent material dispersed within a fibrous matrix, wherein removing at least a portion of water from the swollen absorbent material causes the absorbent material to decrease in size to create voids distributed substantially throughout the matrix.

66. An absorbent composite, comprising absorbent material dispersed within a fibrous matrix, wherein the fibrous matrix comprises crosslinked cellulosic fibers, wherein the fibrous matrix includes voids and passages between voids within the matrix;

wherein the absorbent material is located within some of the voids; and

wherein the absorbent material located within the voids is expandable further into or within the voids.