Comfortable diaper

• US 20070179464A1
• Filed: 03/13/2007
• Published: 08/02/2007
• Est. Priority Date: 02/12/2003
• Status: Active Grant

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Lindner, Torsten, Becker, Uwe, Ehrnsperger, Bruno, Busam, Ludwig
• Granted Patent: US 8,319,005 B2
• Time in Patent Office: Days
• US Class Current: 604/366
• CPC Class Codes: A61F 13/15203 Properties of the article, e.g. stiffness or absorbency chemical aspects A61L15/00
• CPC Class Codes: A61F 13/5323 having absorbent material located in discrete regions, e.g. pockets
• 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 13/535 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 13/539 characterised by the connection of the absorbent layers with each other or with the outer layers
• CPC Class Codes: A61F 2013/530481 having superabsorbent materials, i.e. highly absorbent polymer gel materials

Abstract

An absorbent article, preferably a disposable absorbent article such as a diaper, is disclosed that provides an improved immobilization of absorbent polymer material when the article is fully or partially urine loaded. This absorbent core is useful for providing an absorbent article of increased wearing comfort. Specifically disclosed is an absorbent core useful for an absorbent article comprising a substrate layer and absorbent material, the absorbent material comprising an absorbent polymer material, the absorbent material optionally comprising absorbent fibrous material, the absorbent fibrous material not representing more than 20% of the weight of absorbent polymer material, wherein the absorbent material is immobilized when wet such that the absorbent core achieves a wet immobilization of more than 50%, preferably of more than 60%, 70%, 80% or 90% according to the Wet Immobilization Test described herein.

Claims

1. A disposable absorbent diaper comprising:

a chassis including a liquid impervious backsheet and a liquid pervious topsheet;

a reclosable fastening system joined to said chassis for securing said diaper to a wearer; and

an absorbent core located between said backsheet and said topsheet which includes first and second substrate layers each having absorbent particulate polymer material deposited thereon and encased with thermoplastic material;

said first and second substrate layers are combined together such that said thermoplastic material of each said first and second substrate layers contact one another;

wherein said thermoplastic material has a softening point in a range from about 50°

C. to about 300°

C., a glass transition temperature of less than about 25°

C., and a storage modulus G′

measured at 60°

C. of less than about 300,000 Pa;

wherein said absorbent core has less than about 10% of cellulose fibrous material as compared to the weight of said particulate absorbent polymer.

2. The diaper of claim 1 wherein said thermoplastic material has a molecular weight of more than about 10,000.

3. The diaper of claim 1 wherein the said absorbent core contains from 20% to about 40% by weight of said absorbent core.

4. The diaper of claim 1 wherein said thermoplastic material is in the form of fibers having an average thickness of from about 1 to about 50 micrometers and an average length of from about 5 mm to about 50 cm.

5. The diaper of claim 1 wherein said thermoplastic material is a water insensitive polymer.

6. The diaper of claim 5 wherein said polymer is selected from the group consisting of A-B-A styrene block copolymers.

7. The diaper of claim 6 wherein the A blocks and B blocks of said A-B-A styrene block copolymers are selected from the group consisting of polystyrenes, isoprenes, butadienes, ethylene/butylenes, ethylene/propylenes and mixtures thereof.

8. The diaper of claim 1 wherein said absorbent particulate polymer material is immobilized when wet such that said absorbent core achieves a wet immobilization of more than about 50% according to the Wet Immobilization Test.

9. The diaper of claim 1 wherein said thermoplastic material is selected from the group consisting of metallocene polyolefins, polyalphaolefins and mixtures thereof.

10. The diaper of claim 1 wherein said thermoplastic material is a hot melt adhesive.

11. The diaper of claim 1 wherein said thermoplastic material comprises:

from about 30% to about 60% by weight of a polymer resin having a molecular weight of less than about 5000 and a glass transition temperature T_g of at least about 23°

C.; and

up to about 15% of a plasticizer having a molecular weight of less than about 1000 and a glass transition temperature T_g of at less than about 23°

C.

12. The diaper of claim 1 wherein said absorbent particulate polymer is deposited on said first and second substrate layers in discrete island areas separated by junction areas;

wherein said first and second substrate layers face each other such that said discrete island areas of said first substrate layer is joined to said junction areas of said second substrate layer.

13. The diaper of claim 1 wherein the thermoplastic material has a cross-over temperature T_x of at least about 80°

C.

14. The diaper of claim 1 wherein said thermoplastic material has a storage modulus G′

measured at 60°

C. of less than about 300,000 and more than about 18,000 Pa.

15. The diaper of claim 1 wherein said thermoplastic material has a storage modulus G′

measured at 60°

C. of less than about 300,000 and more than about 30,000 Pa.

16. The diaper of claim 1 wherein said thermoplastic material has a storage modulus G′

measured at 20°

C. of at least about 30,000 Pa and less than about 300,000 Pa.

17. A disposable absorbent pant-type diaper comprising:

a chassis including a liquid impervious backsheet and a liquid pervious topsheet;

at least two side panels joined to said chassis and to each other to form a pant; and

an absorbent core located between said backsheet and said topsheet which includes first and second substrate layers each having absorbent particulate polymer material deposited thereon and encased with thermoplastic material;

said first and second substrate layers are combined together such that said thermoplastic material of each said first and second substrate layers contact one another;

wherein said thermoplastic material has a softening point in a range from about 50°

C. to about 300°

C., a glass transition temperature of less than about 25°

C., and a storage modulus G′

measured at 60°

C. of less than about 300,000 Pa;

wherein said absorbent core has less than about 10% of cellulose fibrous material as compared to the weight of said particulate absorbent polymer.

18. The pant-type diaper of claim 17 wherein said absorbent particulate polymer material is immobilized when wet such that said absorbent core achieves a wet immobilization of more than about 50% according to the Wet Immobilization Test.

19. The pant-type diaper of claim 17 wherein said absorbent particulate polymer is deposited on said first and second substrate layers in discrete island areas separated by junction areas;

wherein said first and second substrate layers face each other such that said discrete island areas of said first substrate layer is joined to said junction areas of said second substrate layer.

20. An absorbent core comprising:

first and second substrate layers each having absorbent particulate polymer material encased with thermoplastic material on said first and second substrate layers in discrete island areas separated by junction areas, wherein said first and second substrate layers face each other such that said discrete island areas of said first substrate layer are joined to said junction areas of said second substrate layer;

said thermoplastic material having cohesion and adhesion behavior such that said first and second substrate layers can be joined together with said thermoplastic material;

wherein said thermoplastic material has a softening point in a range from about 50°

C. to about 300°

C., a glass transition temperature of less than about 25°

C., and a storage modulus G′

measured at 60°

C. of less than about 300,000 Pa;

wherein said absorbent core has less than about 10% of cellulose fibrous material as compared to the weight of said particulate absorbent polymer.