Absorbent Article with a Slitted Absorbent Core

• US 20090062760A1
• Filed: 06/12/2008
• Published: 03/05/2009
• Est. Priority Date: 06/12/2007
• Status: Active Grant

• Current Assignee: Dsg Technology Holding Limited
• Original Assignee: Dsg Technology Holding Limited
• Inventors: Wright, Andrew, Tsang, Patrick King Yu
• Granted Patent: US 8,785,715 B2
• Time in Patent Office: Days
• US Class Current: 604/367
• CPC Class Codes: A61F 13/15642 by depositing continuous layers or pads of fibrous material on single sheets or webs
• CPC Class Codes: A61F 13/15723 Partitioning batts; Cutting
• CPC Class Codes: A61F 13/15731 Treating webs, e.g. for giving them a fibrelike appearance, e.g. by embossing
• CPC Class Codes: A61F 13/15747 Folding; Pleating; Coiling; Stacking; Packaging
• CPC Class Codes: A61F 13/4704 having preferential bending zones, e.g. fold lines or grooves
• CPC Class Codes: A61F 13/49001 having preferential bending zones, e.g. fold lines or grooves
• CPC Class Codes: A61F 13/53409 having a folded core
• 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 13/53713 the layer having a promotional function on liquid propagation in the vertical direction
• CPC Class Codes: A61F 13/53717 the layer having a promotional function on liquid propagation in the horizontal direction
• CPC Class Codes: A61F 13/53747 the layer is facing the topsheet layer is part of the topsheet A61F13/511
• CPC Class Codes: A61F 13/538 characterised by specific fibre orientation or weave
• CPC Class Codes: A61F 2013/15406 Basis weight
• CPC Class Codes: A61F 2013/15504 with a porosity gradient in the vertical or horizontal plane
• CPC Class Codes: A61F 2013/4568 three-dimensional; with split absorbent core
• CPC Class Codes: A61F 2013/530226 with polymeric fibres
• CPC Class Codes: A61F 2013/530343 being natural fibres
• CPC Class Codes: A61F 2013/530489 being randomly mixed in with other material
• CPC Class Codes: A61F 2013/530496 being fixed to fibres
• CPC Class Codes: A61F 2013/5307 characterized by the quantity or ratio of superabsorbent material
• CPC Class Codes: A61F 2013/53782 : with holes
• CPC Class Codes: A61F 2013/53791 : being resilient or elastic
• CPC Class Codes: B32B 2038/045 : Slitting
• CPC Class Codes: B32B 2333/04 : Polymers of esters
• CPC Class Codes: B32B 2367/00 : Polyesters, e.g. PET, i.e. polyethylene terephthalate
• CPC Class Codes: B32B 2555/02 : Diapers or napkins
• CPC Class Codes: B32B 38/04 : Punching, slitting or perforating
• CPC Class Codes: Y10T 156/1026 : with slitting or removal of material at reshaping area prior to reshaping
• CPC Class Codes: Y10T 156/1082 : Partial cutting bonded sandwich [e.g., grooving or incising]
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

The invention relates to slit absorbent articles and the use of slits in absorbent materials to provide improved liquid intake rate, flexibility and softness compared to the unmodified material. The absorbent material, including superabsorbent materials, are particularly useful as absorbent cores in disposable absorbent articles such as diapers, incontinent products, sanitary napkins and the like.

Claims

1. A disposable absorbent article comprising:

an absorbent core including from about 50% to about 97% by weight of a superabsorbent material and from about 3% to about 50% by weight of fibers; and

a modified region of the absorbent core having a higher fluid intake rate as compared to an unmodified region, said modified region having a plurality of slits extending through at least a portion of said absorbent core, said slits promoting the higher fluid intake rate in at least the modified region.

2. The absorbent article in claim 1 wherein a slit level is greater than 0.1 cm⁻

1.

3. The absorbent article in claim 1 wherein said absorbent material includes a MEGATHIN composite.

4. The absorbent article of claim 1 wherein said absorbent core has a basis weight from about 50 grams per square meter (gsm) to about 1000 gsm.

5. The absorbent article of claim 4 wherein said absorbent core has a basis weight from about 100 gsm to about 500 gsm.

6. The absorbent article of claim 1 further comprising at least one region of material discontinuity, said at least one region facilitating folding of the absorbent core along said at least one region of material discontinuity.

7. The absorbent article of claim 6 wherein said at least one region of material discontinuity includes at least one slit extending through at least a portion of said absorbent core.

8. The absorbent article of claim 1 wherein the absorbent core is defined as a layer of absorbent material contained between two or more sheets.

9. The absorbent article in claim 8 wherein the absorbent core includes at least two layers of absorbent material disposed one on top of another.

10. The absorbent article of claim 9 wherein one of the at least two layers of absorbent material is not modified with slits.

11. An absorbent article comprising:

a liquid impervious back sheet; and

an absorbent core containing at least one layer of superabsorbent material (SAP) and including a plurality of slits extending through at least a portion therethrough, said plurality of slits facilitating greater liquid intake of said absorbent core as compared to an identical, but non-slitted, core, and further facilitating improved flexibility of the absorbent core in a predetermined direction.

12. The absorbent article of claim 11 wherein at least some of the plurality of slits extend from a top surface of the absorbent core towards the back sheet.

13. The absorbent article of claim 12 further comprising a top sheet or an acquisition layer or both.

14. The absorbent article of claim 11 wherein the absorbent core includes from about 50% to about 97% by weight of superabsorbent material and from about 3% to about 50% by weight of fibers.

15. The absorbent article in claim 11 wherein a slit level is greater than 0.1 cm⁻

1.

16. The absorbent article of claim 11 wherein said absorbent layer has a basis weight from about 50 grams per square meter (gsm) to about 1000 gsm.

17. The absorbent article of claim 16 wherein said absorbent material layer has a basis weight from about 100 gsm to about 500 gsm.

18. The absorbent article of claim 11 wherein the absorbent core is folded along at least one region of material discontinuity.

19. The absorbent article in claim 11 wherein said absorbent core is subjected to a mechanical softening process.

20. The absorbent article in claim 11 wherein the absorbent core is folded along two or more lines of material discontinuity, wherein said two or more lines are oriented in a product longitudinal direction and located about a central region of the absorbent article, thereby defining an hourglass shape.

21. The absorbent article in claim 11 with the absorbent core further comprising:

a second layer of SAP material having substantially fewer slits as compared to the other layer.

22. A method of manufacturing a disposable absorbent core comprising:

providing a generally liquid impervious back sheet;

connecting an absorbent core to said back sheet, said core including at least one layer containing superabsorbent material; and

slitting said at least one layer of said absorbent core, said slitting improving the liquid intake or flexibility of the absorbent core as compared to a similar, but non-slitted, core.

23. The method of claim 22 wherein said providing includes unrolling the back sheet from a roll.

24. The method of claim 22 wherein said connecting includes an adhesive bonding between said absorbent core and back sheet.

25. The method of claim 22 wherein said slitting occurs after said absorbent core is connected to said back sheet.

26. The method of claim 22 wherein said slitting occurs before said absorbent core is connected to said back sheet.

27. The method of claim 22 wherein said absorbent core includes a second layer containing a superabsorbent material and having substantially fewer slits as compared to the slit layer.

28. The method of claim 27 wherein said second layer has no slits.

29. The method of claim 22 wherein the at least one absorbent layer includes from about 50% to about 97% by weight of superabsorbent material and from about 3% to about 50% by weight of fibers.

30. The method of claim 22 wherein said slitting defines an absorbent core having a slit level of greater than 0.1 cm⁻

1.

31. The method of claim 22 wherein said absorbent core includes a MEGATHIN composite.

32. The method of claim 22 further comprising:

folding the absorbent core along at least one region of material discontinuity.

33. The method of claim 32 wherein said at least one material discontinuity is defined by one or more slits.

34. The method of claim 32 further comprising:

mechanically softening the absorbent core.

35. The method of claim 22 wherein said absorbent core is modified by folding along two or more parallel lines of material discontinuity, wherein said lines are oriented in a product longitudinal direction and located about a central region, said folding producing an hourglass shaped absorbent article.

36. The method of claim 22 wherein said slitting provides a plurality of individual slits aligned in generally in a machine direction.

37. The method of claim 22 wherein said slitting provides a plurality of slits of different lengths.

38. The method of claim 22 wherein said slitting provides a plurality of slits of different depths.

39. The method of claim 22 wherein said slitting provides a plurality of slits of different depths, including slits extending through the absorbent core.

40. The method of claim 22 wherein said slitting provides a plurality of curved slits or linear slits or both.

41. The method of claim 22 wherein said slitting provides a plurality of slits having different angular orientations relative to a machine direction.

42. The method of claim 22 wherein at least some of the slits extending along a substantial portion of a length of the absorbent article.

43. The method of claim 42 wherein said absorbent article is folded about said at least some of the slits to improve user fit or comfort.

44. The method of claim 22 wherein said slitting is defined by a cutting process.

45. The method of claim 44 wherein the cutting process includes a die-cutting process, a shear process, a score process, burst slitting.

46. The method of claim 45 wherein the cutting process is provided by rotating or stationary knives, cutting dies, laser or water jet cutting.

47. The method of claim 34 wherein said mechanically softening occurs prior to said slitting.

48. The method of claim 47 wherein said mechanically softening includes one or more of creping, grooving, ring-rolling and embossing.

49. A method of processing a disposable absorbent article comprising:

providing a generally liquid impervious back sheet;

connecting an absorbent core to said back sheet, said core including at least one layer containing a superabsorbent material; and

imparting a plurality of slits upon said at least one layer of said absorbent core, with at least a substantial portion of said slits being aligned generally in a machine direction so that a machine direction strength is insubstantially decreased as compared to a similar, though non-slitted, absorbent core.

50. The method of claim 49 wherein said imparting provides a patterned array of slits, with at least some of the slits promoting easier folding of the absorbent article along said at least some of the slits.

51. A method of manufacturing a disposable absorbent article comprising:

providing a fluid impervious back sheet;

connecting an absorbent core to said back sheet, with said core including a layer of superabsorbent material; and

slitting at least a portion of said region of superabsorbent material so as to impart greater flexibility and greater liquid intake of said core as compared to a similar non-slit core.

52. The method of claim 51 wherein said slitting renders said absorbent core more flexible about an axis generally aligned in a predetermined direction as compared to a similar non-slit absorbent core.

53. The method of claim 52 wherein said predetermined direction is aligned in a machine direction.

54. The method of claim 52 wherein said predetermined direction is substantially offset from a machine direction.

55. A method of improving liquid intake of a disposable absorbent article comprising:

imparting a plurality of slits upon a portion of an absorbent core of the absorbent article, said portion containing a superabsorbent material, and said imparting rendering said absorbent core with a greater liquid intake rate as compared to a similar, though non-slit, absorbent core.

56. A method of claim 55 with said plurality of slits providing quicker liquid access to an interior portion of the absorbent core to increase a liquid intake of the absorbent core as compared to the similar, though non-slit, core.

57. A method of manufacturing a disposable absorbent article comprising:

selectively defining one or more regions of greater liquid uptake upon an absorbent core having superabsorbent material; and

slitting the absorbent core to provide a plurality of slits, with a greater number of slits per unit area defining a region of greater liquid intake as compared to another region having a fewer number of slits per unit area.

58. The method of claim 57 wherein said one or more regions of greater liquid intake are defined in a manner dependent upon an end use of the absorbent article.

59. The method of claim 57 wherein said slitting defines a patterned region of increased flexibility as compared to another less-flexible region.

60. An absorbent article comprising:

an absorbent core containing at least one layer of superabsorbent material (SAP) and including a plurality of slits extending through at least a portion therethrough, said plurality of slits having a slit width of between 1 micron and 1000 microns to support a capillary flow of liquid into an interior of the absorbent core, said slits facilitating improved liquid intake of said absorbent core as compared to an identical, but non-slit, core.

61. The absorbent article of claim 60 further comprising a liquid pervious sheet positioned between a user and the absorbent core.

62. The absorbent article of claim 61 wherein the plurality of slits are selectively defined upon the absorbent core in pattern selected to control liquid flow into the absorbent core.