Superabsorbent polymers providing long-term generation of free volume in partially hydrated absorbent cores

• US 20040215160A1
• Filed: 01/20/2004
• Published: 10/28/2004
• Est. Priority Date: 04/10/2001
• Status: Abandoned Application

• Current Assignee: Paragon Trade Brands Inc. (Johnson Controls International plc)
• Original Assignee: Paragon Trade Brands Inc. (Johnson Controls International plc)
• Inventors: Baker, Andrew, Chmielewski, Harry J.
• Application Number:
  US10/759,418
• Publication Number:
  US 20040215160A1
• Time in Patent Office: Days
• US Class Current: 604/368
• CPC Class Codes: A61F 13/15658 Forming continuous, e.g. composite, fibrous webs, e.g. involving the application of pulverulent material on parts thereof
• CPC Class Codes: A61F 13/15699 Forming webs by bringing together several webs, e.g. by laminating or folding several webs, with or without additional treatment of the webs
• CPC Class Codes: A61F 13/53 characterised by the absorbing medium A61F13/20 takes precedence
• 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 2013/15463 Absorbency
• CPC Class Codes: A61F 2013/530481 having superabsorbent materials, i.e. highly absorbent polymer gel materials
• CPC Class Codes: A61F 2013/530744 by the absorbency under load
• CPC Class Codes: A61L 15/18 containing inorganic materials
• CPC Class Codes: A61L 15/60 Liquid-swellable gel-forming materials, e.g. super-absorbents

Abstract

An absorbent composition providing unexpectedly high fluid capacity with minimal gel-blocking, articles comprising the absorbent composition and methods of preparing the absorbent composition are disclosed. The absorbent composition optionally comprises a surface crosslinked polymer disbursed within a fibrous matrix of wettable fibers. The surface crosslinked polymer has an FVAUL value of at least about 60 cc after 10 minutes.

Claims

1. A method for preparing an absorbent composition comprising:

providing a first layer of wettable fibers;

distributing on the first layer of wettable fibers a layer of surface crosslinked polymer having a FVAUL value of at least about 60 cc after 10 minutes;

providing a second layer of wettable fibers on top of the layer of surface crosslinked polymer; and

calendaring said layers to form the wettable fibers into a fibrous matrix having the surface crosslinked polymer disbursed therein, said surface crosslinked polymer comprising about 70% by weight to about 95% by weight the absorbent composition and said wettable fibers comprising about 5% by weight to about 30% by weight of the absorbent composition.

2. The method of claim 1, wherein the surface crosslinked polymer is bipolar.

3. The method of claim 1, wherein the surface crosslinked polymer provides minimal gel-blocking properties upon absorption of liquid.

4. The method of claim 1, wherein the surface crosslinked polymer constitutes about 85% by weight to about 95% by weight of the combined weight of the fiberous matrix and the surface crosslinked polymer.

5. The method of claim 1, wherein the surface crosslinked polymer constitutes about 90% by weight to about 95% by weight of the combined weight of the fiberous matrix and the surface crosslinked polymer.

6. The method of claim 1, wherein said wettable fibers constitute about 5% by weight to about 15% by weight of the combined weight of the fiberous matrix and the surface crosslinked polymer.

7. The method of claim 1, wherein said wettable fibers constitute about 5% by weight to about 10% by weight of the combined weight of the fiberous matrix and the surface crosslinked polymer.

8. The method of claim 1, wherein the surface crosslinked polymer comprises a mixed-bed ion-exchange superabsorbent polymer composition.

9. The method of claim 1, wherein the surface crosslinked polymer continues to swell at a substantially constant rate for at least about 0.4 hours after a third dose of urine at a finite volume of urine absorption.

10. The method of claim 1, wherein the surface crosslinked polymer achieves equilibrium swelling levels within about 5 minutes to about 10 minutes after a third dose of urine.

11. The method of claim 1, wherein the surface crosslinked polymer achieves equilibrium swelling levels at an FVAUL value of no less than about 75 cc.

12. The method of claim 1, wherein the FVAUL free volume of the absorbent composition is about 20% to about 70%.

13. The method of claim 1, wherein the FVAUL free volume of the absorbent composition is about 20% to about 60%.

14. The method of claim 1, wherein the FVAUL free volume of the absorbent composition is about 20% to about 50%.

15. The method of claim 1, wherein the FVAUL free volume of the absorbent composition is about 25% to about 50%.

16. The method of claim 1, wherein the surface crosslinked polymer is evenly disbursed within the fibrous matrix.

17. The method of claim 1, wherein the surface crosslinked polymer is poly(acrylic acid).

18. The method of claim 1, wherein the surface crosslinked polymer comprises about 95% by weight of poly(acrylic acid) and about 3% by weight of a crosslinking agent.

19. The method of claim 18, wherein the crosslinking agent is methylene bisacrylamide.

20. The method of claim 18, wherein the surface crosslinked polymer additionally comprises a neutralizing agent.

21. The method of claim 20, wherein the neutralizing agent is triethanol amine.

22. The method of claim 1, wherein the wettable fibers are selected from the group consisting of natural fibers, synthetic fibers, and combinations thereof.

23. The method of claim 1, wherein the wettable fibers are selected from the group consisting of wood pulp (fluff), cotton linters, polyethylene, polypropylene, polyesters, copolymers of polyesters and polyamides, and combinations thereof.

24. The method of claim 1, wherein the wettable fibers are selected from the group consisting of wood pulp fibers, meltblown synthetic fibers and combinations thereof.