Layered absorbent structure with a zoned basis weight and a heterogeneous layer region

• US 6,437,214 B1
• Filed: 01/06/2000
• Issued: 08/20/2002
• Est. Priority Date: 01/06/2000
• Status: Expired due to Term

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: 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): Calvert, John J.
• Assistant Examiner(s): Grayson, Angela J.
• Application Number:
  US09/478,686
• Time in Patent Office: 957 Days
• Field of Search: 604/378, 604/379
• 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 13/535 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 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

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. In additional aspects, at least one primary layer region can have a non-uniform, selectively zoned basis weight distribution. Particular configurations of the at least one primary layer region can be constructed with a target area of such primary layer region having a basis weight which is less than a basis weight of another non-target portion of the primary layer region. Moreover, at least one primary layer region can have a heterogeneous structure. In particular constructions, the at least one primary layer region can include a plurality of two or more sublayers.

Claims

1. An absorbent article, comprising:

a backsheet layer,

a substantially liquid permeable topsheet layer,

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

said second primary layer region having a selectively zoned, non-uniform basis weight;

at least one of said first and second primary layer regions including a plurality of sublayers;

at least one of said first and second primary layer regions having a Liquid Wicking Value of at least about 38%; and

at least one of said primary layer regions including 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 absorbent core has a Combined Conductance-Wicking Value of at least about 14*10⁻

6 cm³.

5. An article as recited in claim 4, 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.

6. 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.

7. 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.

8. An absorbent article which includes an absorbent core having a first primary layer region and at least a second primary layer region;

wherein

said second primary layer region having a selectively zoned, non-uniform basis weight;

said second primary layer region includes a heterogeneous plurality of sublayers;

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 700 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 first primary layer region includes a superabsorbent material in an amount which is not less than about 50 wt % and is not more than about 80 wt %;

said superabsorbent material includes superabsorbent particles having particle sizes which are not less than about 110 μ

m and are not more than about 1000 μ

m;

said superabsorbent material has an MAUL value of not less than about 20 g/g; and

said superabsorbent material has a Tau value of not less than about 0.8 min.

9. An article as recited in claim 8, 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.

10. An article as recited in claim 9, wherein said first primary layer region includes a binder material.

11. An article as recited in claim 8, wherein said second primary layer region includes a plurality of sublayers having uncreped-through-air-dried material.

12. An article as recited in claim 8, 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.

13. An article as recited in claim 8, 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.

14. An article as recited in claim 8, 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.

15. An article as recited in claim 8, wherein a target area of said second primary layer region has a basis weight which is lower than a basis weight of non-target portions of said second primary layer region.

16. An article as recited in claim 8, wherein the target area of said second primary layer region has a basis weight which is not less than about 100 g/m² and is not more than about 250 g/m²;

and

a non-target portion of said second primary layer region has a basis weight which is not less than about 450 g/m² and is not more than about 550 g/m².

17. An article as recited in claim 16, wherein

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 95 wt %;

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

m and not more than about 20 gm;

said fibrous material includes fibers which exhibit a water contact angle of not more than about 70 degrees;

said second primary layer region includes a superabsorbent material in an amount which is not less than about 5 wt % and is not more than about 50 wt %; and

said superabsorbent material includes superabsorbent particles having dry particle sizes which are not less than about 110 μ

m, and are not more than about 1000 μ

m.

18. An article as recited in claim 17, 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.

19. An article as recited in claim 18, wherein said superabsorbent material in said second primary layer region is configured as a superabsorbent layer laminated between layers of uncreped-through-air-dried material.

20. An article as recited in claim 19, wherein said article further comprises a backsheet layer and a substantially liquid permeable topsheet layer which are configured with said absorbent core sandwiched therebetween.

21. An article as recited in claim 20, wherein said absorbent core has a Flow Conductance Value of at least about 7*10⁻

6 cm³; and

at least one of said first and second primary layer regions has a Liquid Wicking Value of at least about 16%.

22. An article as recited in claim 21, wherein at least one of said first and second primary layer regions has a Liquid Wicking Value of at least about 36%.