Absorbent structures containing stiffened fibers and superabsorbent material

• US 5,360,420 A
• Filed: 12/17/1990
• Issued: 11/01/1994
• Est. Priority Date: 01/23/1990
• Status: Expired due to Term

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Cook, Jeffery T., Moore, Danny R., Young, Gerald A., Lash, Glen R.
• Primary Examiner(s): Green, Randall L.
• Assistant Examiner(s): CLARKE, ROBERT A
• Application Number:
  US07/625,776
• Time in Patent Office: 1,415 Days
• Field of Search: 604/378, 604/368, 604/385.1, 604/358
• US Class Current: 604/378
• CPC Class Codes: A61F 13/15203 Properties of the article, e.g. stiffness or absorbency chemical aspects A61L15/00
• CPC Class Codes: A61F 13/537 characterised by a layer facilitating or inhibiting flow in one direction or plane, e.g. a wicking layer A61F13/538 takes precedence
• CPC Class Codes: A61F 13/53747 the layer is facing the topsheet layer is part of the topsheet A61F13/511
• CPC Class Codes: A61F 2013/15406 Basis weight
• CPC Class Codes: A61F 2013/15422 Density
• CPC Class Codes: A61F 2013/530007 being made from pulp
• CPC Class Codes: A61F 2013/530021 being made in soft wood pulp
• CPC Class Codes: A61F 2013/53035 of cotton
• CPC Class Codes: A61F 2013/530583 characterized by the form
• CPC Class Codes: A61F 2013/530613 in fibres
• CPC Class Codes: A61F 2013/53062 being made into a paper or non-woven

Abstract

Absorbent structures having a fluid acquisition/distribution layer with an average dry density of less than about 0.30 g/cc, an average density upon wetting with 1.0% NaCl aqueous solution of less than about 0.20 g/cc, and an average dry basis weight from about 0.001 to about 0.10 g/cm² ; and a fluid storage layer positioned beneath the acquisition/distribution layer comprising at least about 15% superabsorbent material. The fluid acquisition/distribution layer comprises from about 50% to 100% chemically stiffened cellulosic fibers and from 0% to about 50% binding means.

Claims

1. An absorbent article for acquisition, distribution, and storage of bodily fluids, said article comprising:

(a) a fluid pervious topsheet;

(b) a fluid impervious backsheet affixed to said topsheet; and

(c) an absorbent core disposed between said topsheet and said backsheet, said absorbent core having;

(i) a fluid acquisition/distribution layer having an average dry density of less than about 0.30 g/cc, an average density upon saturation with 1% NaCl aqueous solution, dry weight basis, of less than about 0.20 g/cc, and an average dry basis weight of from about 0.001 to about 0.10 g/cm², said acquisition/distribution layer comprising from about 50% to 100%, dry weight basis, of hydrophilic chemically stiffened cellulosic fibers and from 0% to about 50%, dry weight basis, of a binding means

for said fibers; and

(ii) a fluid storage layer, positioned beneath said acquisition/distribution layer relative to said topsheet, comprising at least about 15%, by weight of said storage layer, of superabsorbent material and from 0% to about 85% of a carrier means for said superabsorbent material;

said acquisition/distribution layer having no more than about 6.0% of superabsorbent material and having a top surface area which is from about 15% to about 95% of, and smaller than, the top surface area of said fluid storage layer, said fluid acquisition/distribution layer further being maintained in unimpeded fluid communication with said top surface area of said fluid storage layer.

2. An absorbent article as in claim 1 which is a diaper having a crotch region and wherein there is a margin from the edge of said acquisition/distribution layer to the edge of said fluid storage layer of at least about 1.25 cm. proximate said crotch region.

3. An absorbent article as in claim 1, wherein said acquisition/distribution layer is substantially free of superabsorbent material, has a top surface area which is at least about 25% of the top surface area of said storage layer and which is less than about 90% of the top surface area of the said storage layer, has an average density upon saturation with 1.0% NaCl aqueous solution, dry weight basis, of between about 0.02 g/cc and about 0.15 g/cc, and has an average basis weight of between about O.01g cm² and about 0.08 g/cm², and wherein said superabsorbent material has an Absorbent Capacity of at least about 15 g/g.

4. An absorbent article as in claim 3, wherein said acquisition/distribution layer comprises from about 2% to about 50% of said binding means, wherein said binding means comprises non-chemically stiffened cellulosic material, and wherein a fluid pervious tissue sheet is used to envelope the acquisition/distribution layer, the storage layer or both layers.

5. An absorbent article as in claim 4, wherein said binding means comprises highly refined cellulosic fibers having a freeness of less than about 200 Canadian Standard Freeness, and said acquisition/distribution layer comprises from about 5% to about 15% of said highly refined fibers.

6. An absorbent article as in claim 5, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material comprising discrete particles of absorbent gelling material having an Absorbent Capacity of at least about 20 g/g.

7. An absorbent article, as in claim 5, wherein said acquisition/distribution layer is a wetlaid web.

8. An absorbent article as in claim 4, wherein said binding means comprises high surface area cellulose, and said acquisition/distribution layer comprises from about 2% to about 15% of said high surface area cellulose.

9. An absorbent article, as in claim 8, wherein said acquisition/distribution layer is a wetlaid web.

10. An absorbent article as in claim 8, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material comprising discrete particles of absorbent gelling material having an Absorbent Capacity of at least about 20 g/g.

11. An absorbent article as in claim 3, wherein said acquisition/distribution layer is an airlaid web.

12. An absorbent article as in claim 11, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material comprising discrete particles of absorbent gelling material having an Absorbent Capacity of at least about 20 g/g.

13. An absorbent article as in claim 3, wherein said acquisition/distribution layer is a thermally bonded web comprising from about 10% to about 50% of thermoplastic material, said web being made by preparing a web of a blend of said stiffened fibers and from about 10% to about 50%, total web weight basis, of thermoplastic material, heating the web to melt the thermoplastic material, and cooling the web.

14. An absorbent article as in claim 13, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material comprising discrete particles of absorbent gelling material having an Absorbent Capacity of at least about 20 g/g.

15. An absorbent article as in claim 3, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material having an Absorbent Capacity of at least about 15 g/g. material and said storage layer is substantially free of chemically stiffened cellulosic fibers.

16. An absorbent article as in claim 3, wherein said storage layer comprises superabsorbent fibers.

17. An absorbent structure for acquisition, distribution, and storage of bodily fluids, said structure comprising:

(i) fluid acquisition/distribution layer having an average dry density of less than about 0.30 g/cc, an average density upon saturation with 1% NaCl aqueous solution, dry weight basis, of less than about 0.20 g/cc, and an average dry basis weight of from about 0.001 to about 0.10 g/cm2, said acquisition/distribution layer comprising from about 50% to 100%, dry weight basis, of hydrophilic chemically stiffened cellulosic fibers and from 0% to about 50%, dry weight basis, of a binding means for said fibers; and

(ii) a fluid storage layer, positioned beneath said acquisition/distribution layer, comprising at least about 15%, by weight of said storage layer, of superabsorbent material and from 0% to about 85% of a carrier means for said superabsorbent material;

said fluid acquisition/distribution layer having no more than about 6.0% of superabsorbent material and having a top surface area which is from about 15% to about 95% of, and smaller than, the top surface area of said fluid storage layer, said fluid acquisition/distribution layer further being maintained in unimpeded fluid communication with said top surface area of said fluid storage layer.

18. An absorbent structure as in claim 17 wherein there is a margin from the edge of said acquisition/distribution layer to the edge of said fluid storage layer of at least 0.5 cm. in the regions proximate to where said bodily fluids are discharged during use of the absorbent structure.

19. An absorbent structure as in claim 17, wherein said acquisition/distribution layer is substantially free of superabsorbent material, has a top surface area which is at least about 25% of the top surface area of said storage layer and which is less than about 90% of the top surface area of the said storage layer, has an average density upon saturation with 1.0% NaCl aqueous solution, dry weight basis, of between about 0.02 g/cc and about 0.15 g/cc, and has an average basis weight of between about 0.01g cm² and about 0.08 g/cm², and wherein said superabsorbent material has an Absorbent Capacity of at least about 15 g/g.

20. An absorbent structure as in claim 19, wherein said acquisition/distribution layer comprises from about 2% to about 50% of said binding means, wherein said binding means comprises non-chemically stiffened cellulosic material, and wherein a fluid pervious tissue sheet is used to envelope the acquisition/distribution layer, the storage lawyer or both layers.

21. An absorbent structure as in claim 20, wherein said binding means comprises highly refined cellulosic fibers having a freeness of less than about 200 Canadian Standard Freeness, and said acquisition/distribution layer comprises from about 5% to about 15% of said highly refined fibers.

22. An absorbent structure, as in claim 21, wherein said acquisition/distribution layer is a wetlaid web.

23. An absorbent structure as in claim 21, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material comprising discrete particles of absorbent gelling material having an Absorbent Capacity of at least about 20 g/g.

24. An absorbent structure as in claim 20, wherein said binding means comprises high surface area cellulose, and said acquisition/distribution layer comprises from about 2% to about 15% of said high surface area cellulose.

25. An absorbent structure, as in claim 24, wherein said acquisition/distribution layer is a wetlaid web.

26. An absorbent structure as in claim 24, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material comprising discrete particles of absorbent gelling material having an Absorbent Capacity of at least about 20 g/g.

27. An absorbent structure as in claim 19, wherein said acquisition/distribution layer is an airlaid web that comprises from about 95% to 100% of said stiffened fibers.

28. An absorbent structure as in claim 27, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material comprising discrete particles of absorbent gelling material having an Absorbent Capacity of at least about 20 g/g.

29. An absorbent structure as in claim 19, wherein said acquisition/distribution layer is a thermally bonded web comprising from about 10% to about 50% of thermoplastic material, said web being made by preparing a web of a blend of said stiffened fibers and from about 10% to about 50%, total web weight basis, of thermoplastic material, heating the web to melt the thermoplastic material, and cooling the web.

30. An absorbent structure as in claim 29, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material comprising discrete particles of absorbent gelling material having an Absorbent Capacity of at least about 20 g/g.

31. An absorbent structure as in claim 19, wherein said carrier means for said superabsorbent material comprises a web of cellulosic fibers, and said storage layer comprises from about 15% to about 75% of said superabsorbent material, said superabsorbent material having an Absorbent Capacity of at least about 15 g/g. material and said storage layer is substantially free of chemically stiffened cellulosic fibers.

32. An absorbent structure as in claim 19, wherein said storage layer comprises superabsorbent fibers.