Process for preparing superabsorbent-containing composites

• US 6,376,011 B1
• Filed: 04/07/2000
• Issued: 04/23/2002
• Est. Priority Date: 04/16/1999
• Status: Active Grant

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Lindon, Jack N., Sorebo, Heather A., Hamilton, Wendy L., Reeves, William G., Damay, Emmanuelle C., Hansen, Patsy A.
• Primary Examiner(s): Pianalto, Bernard
• Application Number:
  US09/546,634
• Time in Patent Office: 746 Days
• Field of Search: 427/185, 427/190, 427/195, 427/199, 427/201, 427/204, 427/205, 427/213, 427/222, 427/424
• US Class Current: 427/185
• CPC Class Codes: A61F 2013/15544 Permeability
• CPC Class Codes: A61F 2013/530715 by the acquisition rate
• CPC Class Codes: A61F 2013/530744 by the absorbency under load
• CPC Class Codes: A61L 15/60 Liquid-swellable gel-forming materials, e.g. super-absorbents
• CPC Class Codes: B01J 2/006 Coating of the granules without description of the process or the device by which the granules are obtained to prevent the granules sticking together B01J2/30
• CPC Class Codes: B01J 2/16 by suspending the powder material in a gas, e.g. in fluidised beds or as a falling curtain
• CPC Class Codes: B01J 20/321 consisting of a polymer obtained by reactions involving only carbon to carbon unsaturated bonds
• CPC Class Codes: B01J 20/3236 containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• CPC Class Codes: B01J 20/3238 containing any type of zeolite
• CPC Class Codes: B01J 20/3274 Proteins, nucleic acids, polysaccharides, antibodies or antigens
• CPC Class Codes: B01J 20/3289 Coatings involving more than one layer of same or different nature
• CPC Class Codes: B01J 20/3293 Coatings on a core, the core being particle or fiber shaped, e.g. encapsulated particles, coated fibers
• CPC Class Codes: B01J 2220/68 Superabsorbents
• CPC Class Codes: C08J 2300/14 Water soluble or water swellable polymers, e.g. aqueous gels
• CPC Class Codes: C08J 3/126 Polymer particles coated by polymer, e.g. core shell structures
• CPC Class Codes: C08J 3/203 Solid polymers with solid and/or liquid additives

Abstract

Superabsorbent-containing composites prepared in a fluidized bed coating apparatus according to the process of the present invention contain at least one particle of a superabsorbent material covered with at least a first layer of at least one particle of at least one coating material. The superabsorbent-containing composites prepared in a fluidized bed coating apparatus according to the process of the present invention are particularly suitable for use in sanitary napkins, diapers and other disposable absorbent articles that handle complex fluids.

Claims

1. A process for preparing a superabsorbent-containing composite, the process comprising the steps of:

(a) introducing at least one particle of at least one coating material into a flowing gas stream, the flowing gas stream moving the coating material through a zone where an association agent is applied to the coating material;

(b) introducing at least one particle of at least one superabsorbent material into the flowing gas stream; and

(c) thereafter maintaining the flowing gas stream until the superabsorbent material is covered with at least a first layer of the coating material, the coating material being in intimate association with and covering the surface of the superabsorbent material.

2. The process of claim 1 wherein the flowing gas stream comprises air.

3. The process of claim 1, wherein the coating material comprises a hydrophilic material.

4. The process of claim 3, wherein the coating material comprises a cellulosic material.

5. The process of claim 1, wherein the coating material comprises a silicate.

6. The process of claim 5, wherein the coating material is s elected from the group consisting of precipitated silica, fumed silica, silicon dioxide, zeolites, clays, vermiculite, perlite and mixtures thereof.

7. The process of claim 1, wherein the coating material comprises insoluble proteins.

8. The process of claim 7, wherein the coating material is selected from among the group consisting of zein, texturized vegetable proteins and mixtures thereof.

9. The process of claim 7, wherein the coating material comprises soy protein.

10. The process of claim 1, wherein the association agent is selected from the group consisting of water, volatile organic solvents, aqueous solutions of film-forming materials, synthetic adhesives and mixtures thereof.

11. The process of claim 1, wherein the association agent is selected from the group consisting of water, dried milk, lactose, soy protein, casein, polyvinyl alcohol and mixtures thereof.

12. The process of claim 1, wherein the association agent comprises water and dried milk.

13. The process of claim 1, wherein the association agent comprises water.

14. The process of claim 1, wherein the superabsorbent-containing composite comprises from about 95 to about 45 weight percent superabsorbent material and from about 5 to about 55 weight percent coating material, based on the total weight of the superabsorbent material and the coating material in the superabsorbent-containing composite.

15. The process of claim 1, wherein the superabsorbent-containing composites has a complex fluid retention capacity of between 0 and about 20 g/g.

16. The process of claim 1, wherein the superabsorbent-containing composite has a complex fluid retention capacity of at least about 13 g/g.

17. A process for preparing a superabsorbent-containing composite, the process comprising the steps of:

(a) introducing at least one particle of at least one superabsorbent material into a flowing gas stream, the flowing gas stream moving the superabsorbent material through a zone where an association agent is applied to the superabsorbent material;

(b) introducing at least one particle of at least one coating material into the flowing gas stream; and

(c) thereafter maintaining the flowing gas stream until the superabsorbent material is covered with at least a first layer of the coating material, the coating material being in intimate association with and covering the surface of the superabsorbent material.

18. The process of claim 17, wherein the upward flowing gas stream comprises air.

19. The process of claim 17, wherein the coating material is a hydrophilic material.

20. The process of claim 17, wherein the coating material comprises a cellulosic material.

21. The process of claim 17, wherein the coating material comprises a silicate.

22. The process of claim 21, wherein the coating material is selected from the group consisting of precipitated silica, fumed silica, silicon dioxide, zeolites, clays, vermiculite, perlite and mixtures thereof.

23. The process of claim 17, wherein the coating material comprises insoluble proteins.

24. The process of claim 23, wherein the coating material is selected from among the group consisting of zein, texturized vegetable proteins and mixtures thereof.

25. The process of claim 23, wherein the coating material comprises soy protein.

26. The process of claim 17, wherein the association agent comprises water.

27. The process of claim 17, wherein the superabsorbent-containing composite comprises from about 95 to about 45 weight percent superabsorbent material and from about 5 to about 55 weight percent coating material, based on the total weight of the superabsorbent material and the coating material in the superabsorbent-containing composite.

28. The process of claim 17, wherein the superabsorbent-containing composite has a complex fluid retention capacity of between 0 and about 20 g/g.

29. The process of claim 17, wherein the superabsorbent-containing composite has a complex fluid retention capacity of at least about 13 g/g.

30. A process for preparing a superabsorbent-containing composite, the process comprising the steps of:

(a) introducing at least one particle of at least one superabsorbent material and at least one particle of at least one coating material into a flowing gas stream, the flowing gas stream moving the superabsorbent material and the coating material through a zone where an association agent is applied to the superabsorbent material and the coating material; and

(b) thereafter maintaining the flowing gas stream until the superabsorbent material is covered with at least a first layer of the coating material, the coating material being in intimate association with and covering the surface of the superabsorbent material.

31. The process of claim 30, wherein the upward flowing gas stream comprises air.

32. The process of claim 30, wherein the coating material is a hydrophilic material.

33. The process of claim 30, wherein the coating material comprises a cellulosic material.

34. The process of claim 30, wherein the coating material comprises a silicate.

35. The process of claim 34, wherein the coating material is selected from the group consisting of precipitated silica, fumed silica, silicon dioxide, zeolites, clays, vermiculite, perlite and mixtures thereof.

36. The process of claim 30, wherein the coating material comprises insoluble proteins.

37. The process of claim 36, wherein the coating material is selected from among the group consisting of zein, texturized vegetable proteins and mixtures thereof.

38. The process of claim 36, wherein the coating material comprises soy protein.

39. The process of claim 30, wherein the association agent comprises water.

40. The process of claim 30, wherein the superabsorbent-containing composite comprises from about 95 to about 45 weight percent superabsorbent material and from about 5 to about 55 weight percent coating material, based on the total weight of the superabsorbent material and the coating material in the superabsorbent-containing composite.

41. The process of claim 30, wherein the superabsorbent-containing composite has a complex fluid retention capacity of between 0 and about 20 g/g.

42. The process of claim 30, wherein the superabsorbent-containing composite has a complex fluid retention capacity of at least about 13 g/g.