Reticulated absorbent composite

• US 20030139718A1
• Filed: 11/13/2002
• Published: 07/24/2003
• Est. Priority Date: 05/13/1997
• Status: Abandoned Application

• Current Assignee: National Institute for Strategic Technology Acquisition and Commercialization
• Original Assignee: Weyerhaeuser Company (Weyerhauser)
• Inventors: Li, Yong, Miller, Charles E., Grant, Terry M., Rokman, Kay, Marsh, David G., Laine, Eino, Graef, Peter A., Howard, Fred B., Bunker, Daniel T., Bolstad, Clifford R., Elston, Colin, Edmark, Richard A., Jansson, Juhani
• Application Number:
  US10/294,240
• Publication Number:
  US 20030139718A1
• Time in Patent Office: Days
• US Class Current: 604/374
• 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: B32B 5/22 characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed layer formed of natural mineral fibres or particles next to a foam layer B32B19/047, next to a layer made of particles B32B19/048, or next to a fibrous or filamentary layer B32B19/06; paper layer or cardboard layer next to a paper layer or cardboard layer B32B29/005, next to a foam layer B32B29/007, next to a fibrous or filamentary layer B32B29/02, or next to a particulate layer B32B29/04

Abstract

An absorbent composite having a reticulated core and a fibrous stratum is disclosed. The core and stratum are integrally formed, and the stratum is coextensive with a surface of the core. In one embodiment, the composite includes strata on opposing surfaces of the core. The core includes a fibrous matrix and absorbent material. The fibrous matrix defines voids and passages between the voids, which are distributed throughout the composite. Absorbent material is located within some of the voids. On wetting, absorbent material located in these voids is expandable into the void. Methods for forming the composite and absorbent articles that include the composite are also disclosed.

Claims

1. An absorbent composite comprising a core and a fibrous stratum, the core and stratum being integrally formed;

wherein the stratum is coextensive with a surface of the core,

wherein the core comprises 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.

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 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.

4. The composite of claim 3 wherein the chemically stiffened fibers comprise crosslinked cellulosic fibers.

5. The composite of claim 3 wherein the synthetic fibers are selected from the group consisting of polyolefin, polyester, and polyamide fibers.

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

8. 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.

9. 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.

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

11. The composite of claim 1 wherein the absorbent material is present in an amount from about 2 to about 80 percent by weight of the total composite.

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

13. The composite of claim 12 wherein the wet strength agent is a resin selected from the group consisting of polyamide-epichlorohydrin and polyacrylamide resins.

14. The composite of claim 12 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.

15. The composite of claim 1 wherein the composite is formed by a wetlaid process.

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

101. An absorbent article incorporating the composite of claim 1.

102. The absorbent article of claim 101 wherein the article is at least one of a diaper, a feminine care product, and an adult incontinence product.

6. The composite of claim 6 wherein the polyester fibers are polyethylene terephthalate fibers.

17. A wetlaid absorbent composite comprising a core and a fibrous stratum, the core and stratum being integrally formed;

wherein the stratum is coextensive with a surface of the core,

wherein the core comprises 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.

18. The composite of claim 17 wherein the fibrous matrix comprises crosslinked cellulosic fibers

19. The composite of claim 17 wherein the absorbent material is a superabsorbent material.

20. The composite of claim 17 further comprising a wet strength agent.

103. An absorbent article incorporating the composite of claim 17.

104. The absorbent article of claim 103 wherein the article is at least one of a diaper, a feminine care product, and an adult incontinence product.

21. A foam-formed absorbent composite comprising a core and a fibrous stratum, the core and stratum being integrally formed;

wherein the stratum is coextensive with a surface of the core,

wherein the core comprises 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.

22. The composite of claim 21 wherein the fibrous matrix comprises crosslinked cellulosic fibers

23. The composite of claim 21 wherein the absorbent material is a superabsorbent material.

24. The composite of claim 21 further comprising a wet strength agent.

105. An absorbent article incorporating the composite of claim 21.

106. The absorbent article of claim 105 wherein the article is at least one of a diaper, a feminine care product, and an adult incontinence product.

25. An absorbent composite comprising a core and first and second fibrous strata, the core and strata being integrally formed;

wherein the core is intermediate the first and second strata;

wherein the first and second strata are coextensive with opposing surfaces of the core,

wherein the core comprises 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.

26. The composite of claim 25 wherein the fibrous matrix comprises crosslinked cellulosic fibers

27. The composite of claim 25 wherein the absorbent material is a superabsorbent material.

28. The composite of claim 25 further comprising a wet strength agent.

29. The composite of claim 25 wherein the core and strata are formed from the same fiber furnish.

30. The composite of claim 25 wherein the core and one stratum are formed from the same fiber furnish.

31. The composite of claim 25 wherein the core and strata are formed from different fiber furnishes.

32. The composite of claim 25 wherein the first and second strata are formed from the same fiber furnish.

33. The composite of claim 25 wherein the first and second strata are formed from different fiber furnishes.

34. The composite of claim 25 wherein the core has a basis weight that is different from the basis weight of the stratum.

35. The composite of claim 25 wherein the first stratum has a basis weight that is different from the basis weight of the second stratum.

36. The composite of claim 25 wherein the first and second strata have the same basis weight.

107. An absorbent article incorporating the composite of claim 25.

108. The absorbent article of claim 107 wherein the article is at least one of a diaper, a feminine care product, and an adult incontinence product.

37. A wetlaid absorbent composite comprising a core and first and second fibrous strata, the core and strata being integrally formed;

wherein the core is intermediate the first and second strata;

wherein the first and second strata are coextensive with opposing surfaces of the core,

wherein the core comprises 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.

109. An absorbent article incorporating the composite of claim 37.

110. The absorbent article of claim 109 wherein the article is at least one of a diaper, a feminine care product, and an adult incontinence product.

38. A foam-formed absorbent composite comprising a core and first and second fibrous strata, the core and strata being integrally formed;

wherein the core is intermediate the first and second strata;

wherein the first and second strata are coextensive with opposing surfaces of the core,

wherein the core comprises 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.

111. An absorbent article incorporating the composite of claim 38.

112. The absorbent article of claim 111 wherein the article is at least one of a diaper, a feminine care product, and an adult incontinence product.

39. An absorbent composite comprising absorbent material in a fibrous matrix, wherein the composite has an edgewise ring crush value in the range from about 400 to about 1600 grams and a basis weight in the range from about 250 to about 650 gsm.

40. The composite of claim 39, wherein the absorbent material is present in an amount from about 2 to about 80 percent by weight based on the total weight of the composite.

41. The composite of claim 39, wherein the fibrous matrix comprises crosslinked cellulosic fibers in an amount from about 5 to about 60 percent by weight based on the total weight of the composite.

42. The composite of claim 39, wherein the fibrous matrix comprises matrix fibers in an amount from about 10 to about 60 percent by weight based on the total weight of the composite.

43. The composite of claim 39, wherein the absorbent material is present in about 50 percent by weight based on the total weight of the composite, wherein the fibrous matrix comprises crosslinked fibers present in about 25 percent by weight based on the total weight of the composite and matrix fibers present in about 25 percent by weight based on the total weight of the composite.

44. An absorbent composite comprising absorbent material in a fibrous matrix,

wherein the absorbent material is present in the composite in an amount from about 40 to about 80 percent by weight based on the total weight of the composite;

wherein the fibrous matrix comprises crosslinked cellulosic fibers and matrix fibers;

wherein the weight ratio of crosslinked fibers to matrix fibers is at least about 1;

1.

45. The composite of claim 44, wherein the weight ratio of crosslinked fibers to matrix fibers is at least about 2:

1.

46. The composite of claim 44, wherein the weight ratio of crosslinked fibers to matrix fibers is at least about 3:

1.

47. A method for forming an absorbent composite, comprising the steps of:

combining resilient fibers, matrix fibers, and absorbent material in a dispersion medium to form a fibrous slurry;

depositing the fibrous slurry on a foraminous support;

withdrawing water from the deposited slurry to provide a wet composite having a fibrous stratum adjacent the support; and

drying the wet composite to form an absorbent composite having a core and a fibrous stratum, the core and stratum being integrally formed,

wherein the stratum is coextensive with a surface of the core,

wherein the core comprises 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.

48. The method of claim 47 wherein the resilient fibers comprise crosslinked cellulosic fibers.

49. The method of claim 47 wherein the matrix fibers comprise wood pulp fibers.

50. The method of claim 47 wherein the absorbent material comprises a superabsorbent material.

51. The method of claim 47 wherein the fibrous slurry further comprises a wet strength agent.

52. The method of claim 51 wherein the wet strength agent comprises a polyamide-epichlorohydrin resin.

53. The method of claim 47 wherein the method is a wetlaid method.

54. The method of claim 47 wherein the method is a foam method.

113. An absorbent article incorporating the composite of claim 53.

114. The absorbent article of claim 113 wherein the article is at least one of a diaper, a feminine care product, and an adult incontinence product.

55. A method for forming an absorbent composite, comprising the steps of:

combining resilient fibers, matrix fibers, and absorbent material in a dispersion medium to form a fibrous slurry;

depositing the fibrous slurry on a foraminous support;

withdrawing water from the deposited slurry to provide a wet composite having a fibrous stratum adjacent the support; and

drying the wet composite to form an absorbent composite having a core and a first and second fibrous strata, the core and strata being integrally formed,

wherein the core is intermediate the first and second strata,

wherein the first and second strata are coextensive with opposing surfaces of the core,

wherein the core comprises 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.

56. The method of claim 55 wherein the resilient fibers comprise crosslinked cellulosic fibers.

57. The method of claim 55 wherein the matrix fibers comprise wood pulp fibers.

58. The method of claim 55 wherein the absorbent material comprises a superabsorbent material.

59. The method of claim 55 wherein the fibrous slurry further comprises a wet strength agent.

60. The method of claim 59 wherein the wet strength agent comprises a polyamide-epichlorohydrin resin.

61. The method of claim 55 wherein the method is a wetlaid method.

62. The method of claim 55 wherein the method is a foam method.

63. A method for forming an absorbent composite, comprising the steps of:

combining resilient fibers and matrix fibers in a first dispersion medium to form a first fibrous slurry;

combining absorbent material with a second dispersion medium to form an absorbent material slurry;

combining the absorbent material slurry with the first fibrous slurry to provide a second fibrous slurry;

depositing the second fibrous slurry on a foraminous support;

withdrawing water from the deposited slurry to provide a wet composite having a fibrous stratum adjacent the support; and

drying the wet composite to form an absorbent composite having a core and a fibrous stratum, the core and stratum being integrally formed,

wherein the stratum is coextensive with a surface of the core,

wherein the core comprises 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.

64. The method of claim 63 wherein the method is a wetlaid method.

65. The method of claim 63 wherein the method is a foam method.

66. A method for forming an absorbent composite, comprising the steps of:

combining resilient fibers and matrix fibers in a first dispersion medium to form a first fibrous slurry;

combining absorbent material with a second dispersion medium to form an absorbent material slurry;

combining the absorbent material slurry with the first fibrous slurry to provide a second fibrous slurry;

depositing the second fibrous slurry on a foraminous support;

withdrawing water from the deposited slurry to provide a wet composite having a fibrous stratum adjacent the support; and

drying the wet composite to form an absorbent composite having a core and a first and second fibrous strata, the core and strata being integrally formed,

wherein the core is intermediate the first and second strata,

wherein the first and second strata are coextensive with opposing surfaces of the core,

wherein the core comprises 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.

67. The method of claim 66 wherein the method is a wetlaid method.

68. The method of claim 66 wherein the method is a foam method.

69. A method for forming a fibrous web, comprising the steps of:

(a) forming a first slurry comprising fibers in an aqueous dispersion medium;

(b) forming a second slurry comprising fibers in an aqueous dispersion medium;

(c) moving a first foraminous element in a first path;

(d) moving a second foraminous element in a second path;

(e) passing the first slurry into contact with the first foraminous element moving in the first path;

(f) passing the second slurry into contact with the second foraminous element moving in the second path;

(g) passing a third material between the first and second slurries, wherein the third material does not contact the foraminous elements; and

(h) withdrawing liquid from the first and second slurries and third material through the first and second foraminous elements to provide a fibrous web.

70. The method of claim 69 wherein the web comprises a core intermediate first and second strata coextensive with opposing surfaces of the core, wherein the first stratum comprises first fibers, the second stratum comprises second fibers, and the core comprises the third material.

71. The method of claim 69 wherein the fibers are selected from the group consisting of resilient fibers, matrix fibers, synthetic fibers, and mixtures thereof.

72. The method of claim 69 wherein the fibers comprise crosslinked cellulosic fibers and wood pulp fibers.

73. The method of claim 69 wherein at least one of the first and second slurries further comprises a wet strength agent.

74. The method of claim 69 wherein the third material comprises absorbent material.

75. The method of claim 69 wherein the absorbent material has a residence time in the process of less than about 30 seconds.

76. The method of claim 69 wherein the third material comprises an aqueous suspension of superabsorbent material.

77. The method of claim 69 wherein the third material comprises a fibrous slurry.

78. The method of claim 69 wherein the first slurry is different from the second slurry.

79. The method of claim 69 wherein the first and second paths are substantially vertical.

80. The method of claim 69 practiced in a twin-wire former.

81. The method of claim 80 wherein the twin-wire former is a vertical downflow former.

82. The method of claim 69 wherein the step of passing a third material between the first and second slurries step comprises passing the third material between the first and second slurries after the first and second slurries have contacted the first and second foraminous elements, respectively, and withdrawing liquid therefrom.

83. The method of claim 69 further comprising the step of drying the fibrous web to provide an absorbent composite.

84. A method for forming a fibrous web, comprising the steps of:

(a) forming a first foam slurry comprising first fibers and a surfactant in an aqueous dispersion medium;

(b) forming a second foam slurry comprising second fibers and a surfactant in an aqueous dispersion medium;

(c) moving a first foraminous element in a first path;

(d) moving a second foraminous element in a second path;

(e) passing the first foam slurry into contact with the first foraminous element moving in the first path;

(f) passing the second foam slurry into contact with the second foraminous element moving in the second path;

(g) passing a third material between the first and second foam slurries, wherein the third material does not contact the foraminous elements; and

(h) withdrawing foam and liquid from the first and second foam slurries and third material through the first and second foraminous elements to provide a fibrous web.

85. The method of claim 84 wherein the web comprises a core intermediate first and second strata coextensive with opposing surfaces of the core, wherein the first stratum comprises first fibers, the second stratum comprises second fibers, and the core comprises the third material.

86. The method of claim 84 wherein the fibers are selected from the group consisting of resilient fibers, matrix fibers, synthetic fibers, and mixtures thereof.

87. The method of claim 84 wherein the fibers comprise crosslinked cellulosic fibers and wood pulp fibers.

88. The method of claim 84 wherein at least one of the first and second foam slurries further comprises a wet strength agent.

89. The method of claim 84 wherein the third material comprises absorbent material.

90. The method of claim 89 wherein the absorbent material has a residence time in the process of less than about 30 seconds.

91. The method of claim 84 wherein the third material comprises an aqueous suspension of superabsorbent material.

92. The method of claim 84 wherein the third material comprises a fibrous slurry.

93. The method of claim 84 wherein the third material comprises a foam suspension of superabsorbent material.

94. The method of claim 84 wherein the third material comprises a fibrous foam slurry.

95. The method of claim 84 wherein the first foam slurry is different from the second foam slurry.

96. The method of claim 84 wherein the first and second paths are substantially vertical.

97. The method of claim 84 practiced in a twin-wire former.

98. The method of claim 97 wherein the twin-wire former is a vertical downflow former.

99. The method of claim 84 wherein the step of passing a third material between the first and second foam slurries step comprises passing the third material between the first and second foam slurries after the first and second foam slurries have contacted the first and second foraminous elements, respectively, and withdrawing foam and liquid therefrom.

100. The method of claim 84 further comprising the step of drying the wet composite to provide an absorbent composite.