Absorbent article containing a foam-formed unitary stratified composite

• US 6,518,479 B1
• Filed: 07/21/2000
• Issued: 02/11/2003
• Est. Priority Date: 12/06/1996
• Status: Expired due to Fees

• Current Assignee: National Institute for Strategic Technology Acquisition and Commercialization
• Original Assignee: Weyerhaeuser Company (Weyerhauser)
• Inventors: Matthews, Jeffrey D., Miller, Charles E., Naieni, Shahrokh A., Graef, Peter A., Howard, Fred B., Bunker, Daniel T., Elston, Colin
• Primary Examiner(s): Ruhl, Dennis
• Application Number:
  US09/620,950
• Time in Patent Office: 935 Days
• Field of Search: 604/384, 604/383, 604/378, 604/365, 604/366, 428/131-140, 428/170-172, 428/284, 428/298, 428/300, 428/306.6, 428/309.9, 428/310.5, 428/317.1, 442/402, 442/36, 442/183, 442/224, 442/239, 442/240-243, 442/270-275, 442/352, 442/358, 442/381, 442/383, 442/387, 442/388
• US Class Current: 604/383
• CPC Class Codes: A61F 13/531 having a homogeneous composition through the thickness of the pad A61F13/538, A61F13/539 take precedence
• 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 13/537 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 13/539 characterised by the connection of the absorbent layers with each other or with the outer layers
• CPC Class Codes: B32B 2262/0253 Polyolefin fibres vinyl or acrylic copolymers B32B2262/0223 or B32B2262/0246
• CPC Class Codes: B32B 2262/0261 Polyamide fibres
• CPC Class Codes: B32B 2262/0284 Polyethylene terephthalate [PET] or polybutylene terephthalate [PBT]
• CPC Class Codes: B32B 2262/04 Cellulosic plastic fibres, e.g. rayon
• CPC Class Codes: B32B 2307/726 Permeability to liquids, absorption
• CPC Class Codes: B32B 2307/73 Hydrophobic
• CPC Class Codes: B32B 2555/02 Diapers or napkins
• CPC Class Codes: B32B 5/04 characterised by a layer being specifically extensible by reason of its structure or arrangement , e.g. by reason of the chemical nature of the fibres or filaments
• CPC Class Codes: B32B 5/26 another layer next to it also being fibrous or filamentary relative arrangement of fibres or filaments of different layers B32B5/12
• CPC Class Codes: Y10T 428/249943 Fiber is nonlinear [e.g., crimped, sinusoidal, etc.]
• CPC Class Codes: Y10T 428/249949 Two or more chemically different fibers

Abstract

A unitary stratified composite composed of a first stratum and a second stratum integrally connected by a transition zone is disclosed. The first stratum serves as a liquid acquisition stratum that rapidly acquires and then transfers liquid to the second stratum. The second stratum serves to withdraw liquid from the first stratum and further serves as a temporary storage stratum. Methods for forming the unitary stratified composite are also disclosed.

Claims

1. An absorbent article, comprising:

(a) a liquid pervious topsheet;

(b) a foam-formed absorbent composite, comprising a first stratum, a second stratum, and a transition zone intermediate and coextensive with the first stratum and the second stratum;

the first stratum comprising hydrophobic fibers and a binder;

the second stratum comprising a binder and fibers selected from the group consisting of hydrophilic fibers, hydrophobic fibers, and mixtures thereof; and

the transition zone comprising fibers from the first stratum and the second stratum commingled substantially uniformly across the composite'"'"'s width and along the composite'"'"'s length;

(c) a storage stratum comprising an absorbent fibrous material;

(d) an intermediate stratum interposed between the absorbent composite and the storage stratum; and

(e) a liquid impervious backsheet.

2. The absorbent article of claim 1, wherein at least one of the first or the second stratum comprises synthetic fibers.

3. The absorbent article of claim 1, wherein the second stratum comprises crosslinked cellulosic fibers.

4. The absorbent article of claim 1, wherein at least one of the binders comprises a bicomponent fiber or a wet strength agent.

5. The absorbent article of claim 1, wherein the article is an adult incontinence product.

6. The absorbent article of claim 1, wherein the intermediate stratum comprises a liquid pervious tissue.

7. The absorbent article of claim 1, wherein the intermediate stratum comprises a distribution stratum.

8. The absorbent article of claim 7, wherein the distribution stratum comprises hydrophilic fibers and a binder.

9. The absorbent article of claim 8, wherein at least one of the second stratum or the distribution stratum comprises crosslinked cellulosic fibers.

10. The absorbent article of claim 8, wherein at least one of the second stratum or the distribution stratum comprises crosslinked eucalyptus fibers.

11. An absorbent article, comprising:

(a) a liquid pervious topsheet;

(b) a foam-formed absorbent composite, comprising a first stratum, a second stratum, and a transition zone intermediate and coextensive with the first stratum and the second stratum;

the first stratum comprising first fibers and a binder;

the second stratum comprising second fibers and a binder; and

the transition zone comprising fibers from the first stratum and the second stratum commingled substantially uniformly across the composite'"'"'s width and along the composite'"'"'s length;

(c) a storage stratum comprising an absorbent fibrous material;

(d) an intermediate stratum interposed between the absorbent composite and the storage stratum; and

(e) a liquid impervious backsheet.

12. The absorbent article of claim 11, wherein the first fibers comprise synthetic fibers.

13. The absorbent article of claim 11, wherein the second fibers comprise crosslinked cellulosic fibers.

14. The absorbent article of claim 11, wherein at least one of the binders comprises a bicomponent fiber or a wet strength agent.

15. The absorbent article of claim 11, wherein the article is an adult incontinence product.

16. The absorbent article of claim 11, wherein the intermediate stratum comprises a liquid pervious tissue.

17. The absorbent article of claim 11, wherein the intermediate stratum comprises a distribution stratum.

18. The absorbent article of claim 17, wherein the distribution stratum comprises hydrophilic fibers and a binder.

19. The absorbent article of claim 18, wherein the hydrophilic fibers comprise crosslinked cellulosic fibers.

20. The absorbent article of claim 18, wherein the hydrophilic fibers comprise crosslinked eucalyptus fibers.

21. An absorbent article, comprising:

(a) a liquid pervious topsheet;

(b) a foam-formed absorbent composite, comprising a first stratum, a second stratum, and a transition zone intermediate and coextensive with the first stratum and the second stratum;

the first stratum comprising synthetic fibers and a binder;

the second stratum comprising crosslinked cellulosic fibers and a binder; and

the transition zone comprising fibers from the first stratum and the second stratum commingled substantially uniformly across the composite'"'"'s width and along the composite'"'"'s length;

(c) a storage stratum comprising an absorbent fibrous material;

(d) an intermediate stratum interposed between the absorbent composite and the storage stratum; and

(e) a liquid impervious backsheet.

22. The absorbent article of claim 21, wherein at least one of the binders comprises a bicomponent fiber or a wet strength agent.

23. The absorbent article of claim 21, wherein the article is an adult incontinence product.

24. The absorbent article of claim 21, wherein the intermediate stratum comprises a liquid pervious tissue.

25. The absorbent article of claim 21, wherein the intermediate stratum comprises a distribution stratum.

26. The absorbent article of claim 25, wherein the distribution stratum comprises hydrophilic fibers and a binder.

27. The absorbent article of claim 26, wherein the hydrophilic fibers comprise crosslinked cellulosic fibers.

28. The absorbent article of claim 26, wherein the hydrophilic fibers comprise crosslinked eucalyptus fibers.