Superabsorbing foam, method for the production thereof, and use thereof

• US 20060020049A1
• Filed: 10/06/2003
• Published: 01/26/2006
• Est. Priority Date: 10/10/2002
• Status: Abandoned Application

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Wanior, Mariola, Reifschneider, Andreas, Champ, Samantha
• Application Number:
  US10/530,373
• Publication Number:
  US 20060020049A1
• Time in Patent Office: Days
• US Class Current: 521/99
• CPC Class Codes: A61L 15/425 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 15/60 Liquid-swellable gel-forming materials, e.g. super-absorbents
• CPC Class Codes: B01J 20/26 Synthetic macromolecular compounds
• CPC Class Codes: C08J 2207/12 Sanitary use, e.g. diapers, napkins or bandages
• CPC Class Codes: C08J 2300/14 Water soluble or water swellable polymers, e.g. aqueous gels
• CPC Class Codes: C08J 9/0085 Use of fibrous compounding ingredients C08J9/0076 takes precedence
• CPC Class Codes: C08J 9/28 by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
• CPC Class Codes: C09K 3/1028 Fibres

Abstract

Superabsorbent foam comprising superabsorbent fiber and/or fruit fiber, processes for producing superabsorbent foam having improved wet strength by foaming a crosslinkable aqueous mixture comprising at least 50 mol % neutralized acid-functional monoethylenically unsaturated monomer or at least one basic polymer, crosslinker, superabsorbent synthetic fiber and/or fruit fiber and at least one surfactant and subsequently polymerizing the monomer in the foamed mixture or crosslinking the basic polymer to form a hydrogel foam and use of the thus obtainable foam in hygiene articles to absorb body fluids, in dressing material to cover wounds, as a sealing material, as a packaging material, as a soil improver, as a soil substitute, to dewater sludges, to thicken waterborne paints or coatings in the course of disposing of residual quantities thereof, to dewater water-containing oils or hydrocarbons or as a material for filters in ventilation systems.

Claims

1. A superabsorbent foam comprising at least one of (a) a superabsorbent synthetic fiber and (b) a natural fiber selected from the group consisting of apple fiber, orange fiber, tomato fiber, wheat fiber, oat fiber, and mixtures thereof.

2. The superabsorbent foam of claim 1 obtainable by foaming a polymerizable aqueous mixture comprising at least a 50 mol % neutralized acid-functional monoethylenically unsaturated monomer or at least one basic polymer, a crosslinker, a superabsorbent fiber, and at least one surfactant, and subsequently polymerizing and/or crosslinking the foamed mixture.

3. The superabsorbent foam of claim 2 wherein the polymerizable aqueous mixture contains from 0.01 to 10% by weight of superabsorbent fiber, based on the monomer.

4. The superabsorbent foam of claim 2 wherein the polymerizable aqueous mixture contains from 0.1 to 5% by weight of the superabsorbent fiber, based on the monomer.

5. The superabsorbent foam of claim 1 wherein the foam is surface postcrosslinked.

6. The superabsorbent foam of claim 2 wherein the polymerizable aqueous mixture comprises at least a 50% aqueous sodium or potassium hydroxide solution neutralized acrylic acid, a crosslinker containing at least two ethylenically unsaturated double bonds, a radical-forming initiator, a superabsorbent fiber comprising a hydrolyzed and subsequently crosslinked copolymer of isobutene and maleic anhydride, and at least one surfactant.

7. The superabsorbent foam of claim 2 wherein the polymerizable aqueous mixture comprises at least one basic polymer selected from the group consisting of polymers containing vinylamine units, polymers containing vinylguanidine units, polymers containing dialkylaminoalkyl(meth)acrylamide units, polyethyleneimines, ethyleneimine-grafted polyamidoamines, and polydiallyldimethylammonium chlorides.

13. An article comprising the superabsorbent foam of claim 1.

14. The article of claim 13 selected from the group consisting of a hygiene article to absorb body fluids, a dressing article to cover wounds, and a ventilation system filter.

15. A method of dewatering a liquid comprising contacting the liquid with a superabsorbent foam of claim 1.

16. The method of claim 15 wherein the liquid is a sludge or a water-containing oil or hydrocarbon.

17. A sealing or packaging material comprising a superabsorbent foam of claim 1.

18. A soil adjuvant comprising a superabsorbent foam of claim 1.

19. A method of thickening an aqueous liquid to facilitate disposal thereof, comprising admixing the aqueous liquid with a superabsorbent foam of claim 1 to thicken the aqueous liquid.

8. A process for producing a superabsorbent foam having improved wet strength, which comprises foaming a crosslinkable aqueous mixture comprising at least a 50 mol % neutralized acid-functional monoethylenically unsaturated monomer or at least one basic polymer, a crosslinker, at least one of (a) a superabsorbent synthetic fiber and (b) a natural fiber selected from the group consisting of apple fiber, orange fiber, tomato fiber, wheat fiber, and mixtures thereof, and at least one surfactant, and subsequently polymerizing the monomer in the foamed mixture or crosslinking the basic polymer in the foamed mixture to form a hydrogel foam.

9. The process claim 8 wherein the aqueous mixture comprises from 0.01 to 10% by weight by weight of the superabsorbent fiber.

10. The process of claim 8 wherein the foaming of the aqueous polymerizable mixture is effected by dissolving an inert gas in the mixture at from 2 to 400 bar and subsequently decompressing the mixture to atmospheric.

12. The process of claim 8 wherein the aqueous mixtures comprise from 0.1 to 5% by weight of the superabsorbent fiber.

11. (canceled)