Methods for forming a fluted composite

• US 6,630,054 B1
• Filed: 09/18/2000
• Issued: 10/07/2003
• Est. Priority Date: 03/19/1998
• Status: Expired due to Fees

• Current Assignee: National Institute for Strategic Technology Acquisition and Commercialization
• Original Assignee: Weyerhaeuser Company (Weyerhauser)
• Inventors: Howard, Fred B., Bolstad, Clifford R., Miller, Charles E., Graef, Peter A., Bunker, Daniel T.
• Primary Examiner(s): Fortuna, Jose A.
• Application Number:
  US09/664,576
• Time in Patent Office: 1,114 Days
• Field of Search: 162/101, 162/189-190, 162/123, 162/125, 162/132-133, 162/157.6, 162/158, 162/164.6, 162/164.3
• US Class Current: 162/101
• CPC Class Codes: A61F 13/15617 Making absorbent pads from fibres or pulverulent material with or without treatment of the fibres
• 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 13/534 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 13/536 having discontinuous areas of compression
• CPC Class Codes: A61F 2013/1539 being expandable
• CPC Class Codes: A61F 2013/4581 with absorbent core in separated pieces
• CPC Class Codes: A61F 2013/530386 with pulp and polymeric
• CPC Class Codes: A61F 2013/530481 having superabsorbent materials, i.e. highly absorbent polymer gel materials
• CPC Class Codes: D21C 9/002 by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
• CPC Class Codes: D21F 11/002 by using a foamed suspension
• CPC Class Codes: D21F 11/006 Making patterned paper
• CPC Class Codes: D21F 11/04 paper or board consisting on two or more layers
• CPC Class Codes: D21F 11/14 Making cellulose wadding, filter or blotting paper
• CPC Class Codes: D21F 9/006 paper or board consisting of two or more layers
• CPC Class Codes: D21H 11/20 Chemically or biochemically modified fibres

Abstract

Methods for forming an absorbent fibrous composite containing absorbent material dispersed in bands through the composite and along the composite'"'"'s length are disclosed. The methods generally include depositing a fibrous slurry on a foraminous support to form a web and depositing or injecting absorbent material into the web across its width to provide a web having absorbent material in bands along the composite'"'"'s length. Drying the web provides a fluted absorbent composite. In one embodiment, the method is a wetlaid method and in another embodiment, the method is a foam-forming method. Preferably, the methods are twin-wire forming methods.

Claims

1. A method for forming a fibrous web, comprising the steps of:

(a) forming a first foam slurry comprising fibers and a surfactant in an aqueous dispersion medium;

(b) forming a second foam slurry comprising fibers and a surfactant in an aqueous dispersion medium;

(c) moving a first foraminous element in a first path;

(d) moving a second foraminous element in a second path, a nip area provided at a location along the first and second paths;

(e) passing the first slurry into contact with the first foraminous element moving in the first path;

(f) passing the second slurry into contact with the second foraminous element moving in the second path;

(g) passing a third material between the first and second slurries, wherein the third material does not contact the foraminous elements, and wherein the third material is introduced at a plurality of points; and

(h) withdrawing foam and liquid from the first and second slurries and third material through the first and second foraminous elements, respectively, to provide a fibrous web.

2. The method of claim 1 wherein the fibers are selected from the group consisting of resilient fibers, matrix fibers, synthetic fibers, and mixtures thereof.

3. The method of claim 1 wherein the fibers comprise crosslinked cellulosic fibers and wood pulp fibers.

4. The method of claim 1 wherein at least one of the first and second foam slurries further comprises a wet strength agent.

5. The method of claim 4 wherein the wet strength agent comprises a polyamide-epichlorohydrin resin.

6. The method of claim 1 wherein the third material comprises absorbent material.

7. The method of claim 6 wherein the absorbent material comprises superabsorbent material.

8. The method of claim 1 wherein the third material comprises an aqueous suspension of superabsorbent material.

9. The method of claim 1 wherein the third material comprises a fibrous slurry.

10. The method of claim 1 wherein the third material comprises a fibrous slurry comprising absorbent material.

11. The method of claim 1 wherein the first slurry is different from the second slurry.

12. The method of claim 1 wherein the first and second paths are substantially vertical.

13. The method of claim 1 practiced with a twin-wire former.

14. The method of claim 1 wherein the step of passing a third material between the first and second slurries by introducing the third material at a plurality of points provides bands of the third material into the web formed.

15. The method of claim 1 wherein the step of passing a third material between the first and second slurries by introducing the third material at a plurality of points comprises adjusting the positions of at least some of the plurality of points to adjust the introduction points in a first dimension toward and away from the nip area.

16. The method of claim 1 wherein the step of passing a third material between the first and second slurries by introducing the third material at a plurality of points comprises adjusting the positions of at least some of the plurality of points to adjust the introduction points in a second dimension substantially perpendicular to the first dimension, closer to one foraminous element or the other.

17. The method of claim 1 wherein the step of passing a third material between the first and second slurries by introducing the third material at a plurality of points is practiced utilizing a plurality of conduits.

18. The method of claim 17 wherein the plurality of conduits comprises conduits having at least two different lengths.

19. The method of claim 17 wherein steps (e), (f), and (g) are practiced by providing dividing walls extending part of the length of the conduits toward the nip area.

20. The method of claim 1 wherein the step of passing a third material between the first and second slurries step comprises passing the third material between the first and second slurries after the first and second slurries have contacted the first and second foraminous elements, respectively, and withdrawing- foam and liquid therefrom.

21. The method of claim 1 wherein the step of passing a third material between the first and second slurries step comprises passing the third material through a plurality of conduits and passing a fourth material through a plurality of different conduits to provide bands of third and fourth materials in the web formed.

22. The method of claim 21 wherein the step of passing the third material and material between the first and second slurries comprises introducing the third and fourth materials at different spaced distances from the nip area.

23. The method of claim 1 further comprising the step of drying the wet composite to provide an absorbent composite.