Methods of making absorbent members having density profile

Patent metadata

Field	Value
Publication number	US-9452089-B2
Application number	US-201213455194-A
Country	US
Kind code	B2
Filing date	Apr 25, 2012
Priority date	Apr 26, 2011
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

Absorbent members and methods of making the same are disclosed. In one embodiment, the absorbent member is a unitary absorbent fibrous web having a density profile through its thickness. In one embodiment, the density profile is relatively centered through the thickness of the web and the maximum density of the web is located between about 35% and about 65% of the distance through the thickness of the web. In one embodiment, the method involves subjecting a precursor web to at least one cycle (or pass) through a mechanical deformation process. Typically, the method involves subjecting the precursor web to multiples cycles (or passes) through a mechanical deformation process.

First claim

What is claimed is:

1. A method for making an absorbent member having a thickness, said method comprising:
a) providing a precursor web material, said precursor web material comprising a wetlaid cellulosic fibrous structure, said precursor web material having a first surface, a second surface, and a thickness;
b) providing a pair of forming members having a machine direction orientation and a cross-machine direction orientation, said forming members comprising:
a first forming member having a surface comprising a plurality of first forming elements, wherein said first forming elements comprise discrete male forming elements that are spaced apart in the machine direction; and
a second forming member having a surface comprising a plurality of second forming elements, wherein said second forming elements comprise male forming elements;

c) providing a third forming member having a machine direction orientation and a cross-machine direction orientation, said third forming member having a surface comprising a plurality of third forming elements, wherein said third forming elements comprise discrete male forming elements that are spaced apart in the machine direction;
d) mechanically impacting said precursor web material by placing said precursor web material between said first and second forming members, wherein said forming elements on said first forming member penetrate into the first surface of said precursor web material at least part of the way into the thickness of said precursor web material, and said forming elements on said second forming member penetrate into the second surface of said precursor web material at least part of the way into the thickness of said precursor web material; and
e) repeating a step of mechanically impacting said precursor web to form an absorbent member by mechanically impacting said precursor web material by placing said precursor web material between said third forming member and either the first forming member, the second forming member or another forming member, wherein said forming elements on said third forming member penetrate into the first or second surface of said precursor web material at least part of the way into the thickness of said precursor web material,
wherein the only material that is mechanically impacted in steps d) and e) consists of wetlaid cellulosic fibrous material,
wherein said absorbent member is provided with a density profile through at least a portion of its thickness, and
wherein said first and second surfaces of said precursor web material comprise first and second surfaces, respectively, of said absorbent member, and said first and second surfaces of said absorbent member are substantially planar and not substantially embossed.

2. The method of claim 1 wherein the precursor web material is selected from the group consisting of: drylap, liner board, paper board, post-consumer recycled material, filter paper, and combinations thereof.

3. The method of claim 2 wherein the precursor material consists of treated drylap.

4. The method of claim 1 wherein the precursor web has an initial density prior to mechanically impacting the same, and the absorbent member formed by the method has a mean maximum density, and the mean maximum density of the absorbent member is less than the initial density of the precursor web.

5. The method of claim 1 wherein the precursor web material has a burst strength of less than about 1,000 kPa.

6. The method of claim 1 wherein the precursor web is treated with debonders.

7. The method of claim 1 wherein said pair of forming members define a clearance which is the shortest distance between the forming elements on one forming member and the forming elements on the opposed forming member, and the clearance between the forming elements is less than the thickness of the precursor web.

8. The method of claim 1 wherein said pair of forming members define a depth of engagement, and the ratio of the thickness of the precursor web to the absolute value of the depth of engagement is greater than 1.

9. The method of claim 1 wherein said pair of forming members comprise counter-rotating rolls defining a nip therebetween.

10. The method of claim 9 wherein said counter-rotating rolls rotate at substantially the same surface speed.

11. The method of claim 9 wherein said counter-rotating rolls rotate at different surface speeds, and the surface speed differential between said rolls is greater than about 0.3%.

12. The method of claim 9 wherein the first forming member comprises a first roll, and the second forming member comprises a second roll, and at least said first roll comprises a plurality of alternating discrete ridges and grooves on its surface, wherein the ridges have breaks therein to provide forming elements in the form of teeth.

13. The method of claim 12 wherein said teeth have a tip radius that is less than about 0.02 inch (0.5 mm).

14. The method of claim 1 wherein at least one of said first and second forming members has at least one relatively smooth region on its surface.

15. The method of claim 9 comprising inserting said web material through multiple nips wherein said multiple nips are formed by plural rolls arranged in a paired configuration.

16. The method of claim 9 comprising inserting said web material through multiple nips wherein said multiple nips are formed by plural rolls arranged in a nested configuration in which there are at least four rolls and at least two of the rolls define two or more nips with the other rolls.

17. The method of claim 9 comprising inserting said web material through multiple nips wherein said multiple nips are formed by plural rolls arranged in a combination of nested and paired configurations, wherein in the nested configuration there are at least four rolls and at least two of the rolls define two or more nips with the other rolls.

18. The method of claim 1 wherein the forming elements on said forming members only penetrate part of the way through the thickness of said precursor web material.

19. The method of claim 1 wherein the forming elements on at least one of said forming members penetrate completely through the thickness of said precursor web material.

20. The method of claim 1 further comprising a step of feeding said absorbent member into a hammer mill.

21. A method of making an absorbent article on an absorbent article manufacturing line wherein the method of claim 1 is carried out on said absorbent article manufacturing line.

22. The method of claim 9 wherein said nip comprises a first nip, and said method further comprises a subsequent step of passing said web material through at least one additional nip between two additional rolls after said web material is inserted through said first nip, said additional rolls having surfaces that form said additional nip, wherein at least regions of the surfaces of at least one of said additional rolls are relatively smoother in at least a portion of said additional nip in comparison to the surfaces of the rolls in said first nip, wherein said additional nip compacts at least a portion of said precursor web material.

23. The method of claim 9 wherein the first forming elements have a spacing therebetween and the second forming elements have a spacing therebetween, said method further comprising a prior and/or subsequent step of passing said web material through at least one additional nip between two additional rolls, said additional rolls having forming elements the

Assignees

• Marinelli Luigi
• Lake Kirk Wallace
• Orr Jill Marlene
• Strube John Brian
• Priessman Keith Robert
• Cimini Carmine
• Dipilla Mario
• Procter & Gamble

Inventors

• Marinelli Luigi
• Lake Kirk Wallace
• Orr Jill Marlene
• Strube John Brian
• Priessman Keith Robert
• Cimini Carmine
• Dipilla Mario

Classifications

• B26F1/20

  with tools carried by a rotating drum or similar support (B26F1/22 takes precedence) · CPC title

• A61F13/15731 Primary

  Treating webs, e.g. for giving them a fibrelike appearance, e.g. by embossing · CPC title

• B31F1/07

  Embossing {, i.e. producing impressions formed by locally deep-drawing, e.g. using rolls provided with complementary profiles}({B31F1/128 takes precedence;} corrugating B31F1/20; embossing in combination with printing B41F19/02, B41M1/24; typewriters for embossing B41J3/38; stamping in combination with deforming B41K3/36) · CPC title

• A61F2013/15439

  with a density gradient in the vertical plane · CPC title

• B26F1/24

  Perforating by needles or pins · CPC title