Layered absorbent structure

• US 6,383,960 B1
• Filed: 03/03/2000
• Issued: 05/07/2002
• Est. Priority Date: 10/08/1997
• Status: Expired due to Term

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Chang, Kuo-Shu Edward, Li, Yong, Ranganathan, Sridhar, Zhang, Xiaomin, Melius, Shannon Kathleen, Sawyer, Lawrence Howell, McDowall, Debra Jean, Little, Sylvia Bandy, Dodge, Richard Norris II, Grube, Violet May, Zenker, David Louis, Everett, Rob David, Bolwerk, Thomas Gerald, Matthews, Billie Jean, Gryskiewicz, Stanley Michael
• Primary Examiner(s): Kelly, Cynthia H.
• Assistant Examiner(s): GRAY, JILL M
• Application Number:
  US09/519,045
• Time in Patent Office: 795 Days
• Field of Search: 428/219, 428/913, 428/124, 428/195, 442/412, 442/413, 442/47, 442/394, 442/389, 442/391, 442/417, 442/381, 604/378, 604/370, 604/385.1, 604/385.2, 162/146, 162/157.6
• US Class Current: 442/394
• CPC Class Codes: A61F 13/535 inhomogeneous in the plane of the pad, e.g. core absorbent layers being of different sizes A61F13/5323, A61F13/537 take precedence
• CPC Class Codes: A61F 2013/530481 having superabsorbent materials, i.e. highly absorbent polymer gel materials
• CPC Class Codes: A61F 2013/5355 with terraced core
• CPC Class Codes: Y10T 442/481 Chemically deposited metal layer [e.g., chemical precipitation or electrochemical deposition or plating, etc.]
• CPC Class Codes: Y10T 442/659 Including an additional nonwoven fabric
• CPC Class Codes: Y10T 442/668 Separate nonwoven fabric layers comprise chemically different strand or fiber material
• CPC Class Codes: Y10T 442/674 Nonwoven fabric with a preformed polymeric film or sheet
• CPC Class Codes: Y10T 442/693 Including a paper layer
• CPC Class Codes: Y10T 442/695 Including a wood containing layer

Abstract

A distinctive absorbent article includes an absorbent core having multiple absorbent layers, wherein the absorbent layers interact in such a manner which preferentially locates absorbed liquid in an appointed, high saturation wicking layer. The localization of the liquid within this wicking layer increases the potential of this layer to move liquid through capillary action due to the higher saturation level and increased amount of liquid available. The intake capability of the absorbent system is maintained or improved over current systems by keeping a second layer of the absorbent system at low saturation levels through as many insults of the product as possible, while providing optimum intake performance through appropriate control of the composite properties. The low saturation in this layer provides void volume for the incoming insult as well, as a high permeability, thus increasing the intake rate of the absorbent system as a whole, but the structure of the low saturation layer is also balanced to provide an appropriately high level of capillary tension to provide enough control of the liquid to stop leakage from occurring. This low saturation layer is used in addition to a surge material and provides intake functionality in addition to that provided by the surge material. In particular aspects of the invention, the body side layer of the absorbent core does not extend over the entire surface of the overall absorbent core, therefore is not used as the high saturation, wicking layer, but as the intake layer. This arrangement also allows the intake layer to be in direct contact with the incoming liquid, therefore allowing for more immediate access and improved intake function.

Claims

1. An absorbent article, comprising:

a backsheet layer;

a substantially liquid permeable topsheet layer; and

an absorbent composite structure sandwiched between said backsheet and topsheet layers, said absorbent composite including an absorbent core having a first, superabsorbent containing, fibrous primary layer region and at least a second, superabsorbent containing, fibrous primary layer region;

wherein

at least one of said first and second primary layer regions has a Liquid Wicking Value of at at least one of said primary layer regions includes a superabsorbent material which exhibits a Tau value of not less than about 0.8 min.

2. An article as recited in claim 1, wherein said absorbent core has a dry thickness of not more than about 6 mm, and a minimum crotch width of not more than about 10 cm.

3. An article as recited in claim 1, wherein said article is configured for use by an adult, and wherein said absorbent core has a dry thickness of not more than about 6 mm, and a minimum crotch width of not more than about 14 cm.

4. An article as recited in claim 1, wherein said first primary layer region is located on a bodyside of the absorbent composite, and said second primary layer region is located relatively outward from said first layer region.

5. An absorbent article as recited in claim 1, wherein at least one of said primary layer regions includes a superabsorbent material having a Modified Absorbency Under Load value of at least about 20 g/g.

6. An article as recited in claim 1, wherein said first primary layer region includes a first superabsorbent having a first Tau value;

said second primary layer region includes a second superabsorbent having a second Tau value; and

said first Tau value is greater than said second Tau value.

7. An article as recited in claim 6, wherein said first primary layer region is positioned at a bodyside of said absorbent core;

and a ratio of said first Tau value to said second Tau value is at least about 2;

1.

8. An article as recited in claim 7, wherein said ratio of said first Tau value to said second Tau value is at least about 5:

1.

9. An absorbent article, comprising:

a backsheet layer;

a substantially liquid permeable topsheet layer; and

an absorbent system sandwiched between said backsheet and topsheet layers, said absorbent system including an absorbent core having a first, superabsorbent containing, fibrous primary layer region and at least a second, superabsorbent containing, fibrous primary layer region;

wherein

said absorbent core has a combined Conductance-Wicking Value of at least about at least one of said primary layer regions includes a superabsorbent material which exhibits a Tau value of not less than about 0.8 min.

10. An article as recited in claim 9, wherein said absorbent core has a dry thickness of not more than about 6 mm and a minimum crotch width of not more than about 10 cm.

11. An absorbent article which includes an absorbent core having a first, superabsorbent containing, fibrous primary layer region and at least a second, superabsorbent containing, fibrous primary layer region;

wherein

said absorbent core has a longitudinal length, a lateral width and an appointed front-most edge;

said first primary layer region has a basis weight of not less than about 100 g/m² and not more than about 500 g/m²;

said first primary layer region has a first layer region density of not less than about 0.03 g/cm³ and not more than about 0.4 g/cm³;

said first primary layer region includes fibrous material in an amount which is not less than about 25 wt % and is not more than about 80 wt %;

said fibrous material includes fibers having fiber sizes which are not less than about 4 μ

m and not more than about 20 μ

m;

said fibrous material includes fibers which exhibit a water contact angle of not more than about 65 degrees;

said first primary layer region includes a superabsorbent material in an amount which is not less than about 20 wt % and is not more than about 75 wt %;

said superabsorbent material in said first primary layer includes superabsorbent particles having particle sizes which are not less than about 140 μ

m and are not more than about 1000 μ

m;

said superabsorbent material in said first primary layer has a MAUL value of not less than about 20 g/g;

said superabsorbent material in said first primary layer has a Tau value of not less than about 0.8 min; and

said first primary layer region has a Liquid Wicking Value of at least about 36%.

12. An article as recited in claim 11, wherein said first primary layer region is substantially coterminous with side edges of said second primary layer region;

and

said first primary layer region contained within a zone which begins at a laterally extending line positioned about 7% of the core length inboard from said front-most edge of the absorbent core and extends to a laterally extending line positioned about 62% of the core length inboard from said front-most edge of the absorbent core.

13. An article as recited in claim 12, wherein said first primary layer region includes a binder material.

14. An article as recited in claim 11, wherein said first primary layer region includes a plurality of sublayers.

15. An article as recited in claim 11, wherein said second primary layer region has a longitudinal extent which is greater than a longitudinal extent of said first primary layer region;

and said second primary layer region has a lateral extent which is substantially coterminous with said first primary layer region.

16. An article as recited in claim 11, wherein said second primary layer region has a longitudinal extent which is greater than a longitudinal extent of said first primary layer region;

said second primary layer region has a lateral extent which is less than a lateral extent of said first primary layer region; and

a lateral extent of at least a portion of said second primary layer region is not less than about 30% of a lateral extent of a correspondingly adjacent portion of said first primary layer region.

17. An article as recited in claim 11, wherein said second primary layer region has a longitudinal extent which is greater than a longitudinal extent of said first primary layer region;

said second primary layer region has a lateral extent which is greater than a lateral extent of said first primary layer region;

a lateral extent of at least a portion of said first primary layer region is not less than about 30% of a lateral extent of a correspondingly adjacent portion of said second primary layer region.

18. An article as recited in claim 17, wherein said second primary layer region has a substantially uniform basis weight.

19. An article as recited in claim 11, wherein said second primary layer region has a basis weight which is not less than about 300 g/m² and is not more than about 700 g/m²;

said second primary layer region has a second layer region density of not less than about 0.1 g/cm³ and not more than about 0.3 g/cm³;

said second primary layer region includes fibrous material in an amount which is not less than about 50 wt % and is not more than about 80 wt %;

said fibrous material includes fibers having fiber diameters which are not less than about 4 μ

m and not more than about 20 μ

m;

said fibrous material includes fibers which exhibit a water contact angle of not more than about 65 degrees;

said second primary layer region includes a superabsorbent material in an amount which is not less than about 20 wt % and is not more than about 50 wt %; and

said superabsorbent material includes superabsorbent particles having particle sizes which are not less than about 140 μ

m, and are not more than about 1000 μ

m.

20. An article as recited in claim 19, wherein said superabsorbent material in said second primary layer region has a MAUL value of not less than about 20 g/g, and has a Tau value of at least about 0.4 minutes.

21. An article as recited in claim 20, wherein said superabsorbent material in said second primary layer region is configured as a layer laminated between tissue layers.

22. An article as recited in claim 21, wherein said article further comprises a backsheet layer and a substantially liquid permeable topsheet layer which are configured with said absorbent core sandwiched therebetween.

23. An article as recited in claim 22, wherein said absorbent core has a Flow Conductance Value of at least about 7*10⁻

6 cm³.

24. An article as recited in claim 23, wherein said second primary layer region includes a binder material.

25. An article as recited in claim 19, wherein said absorbent core has a dry thickness of not more than about 6 mm, and a minimum crotch width of not more than about 10 cm.

26. An article as recited in claim 19, wherein said article is configured for use by an adult, and wherein said absorbent core has a dry thickness of not more than about 6 mm, and a minimum crotch width of not more than about 14 cm.

27. An article as recited in claim 19, wherein said absorbent core has a Flow Conductance Value of at least about 7*10⁻

6 cm³.

28. An article as recited in claim 27, wherein said absorbent core has a Conductance-Wicking Value of at least about 14*10⁻

6 cm³.

29. An article as recited in claim 19, wherein said absorbent core has a Conductance-Wicking Value of at least about 14*10⁻

6 cm³.

30. An article as recited in claim 11, wherein said first primary layer region is positioned at a bodyside of said absorbent core;

said first primary layer region includes a first superabsorbent having a first Tau value;

said second primary layer region includes a second superabsorbent having a second Tau value; and

a ratio of said first Tau value to said second Tau value is at least about 2;

1.

31. An article as recited in claim 30, wherein said ratio of said first Tau value to said second Tau value is at least about 5:

1.