Method of making a belt-creped, absorbent cellulosic sheet with a perforated belt

Patent metadata

Field	Value
Publication number	US-9388534-B2
Application number	US-201514620251-A
Country	US
Kind code	B2
Filing date	Feb 12, 2015
Priority date	Apr 14, 2004
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

A method of making a belt-creped absorbent cellulosic sheet. A papermaking furnish is compactively dewatered to form a dewatered web. The dewatered web is applied to a translating transfer surface. The web is belt-creped from the transfer surface utilizing a polymeric creping belt having perforations. The web is creped from the transfer surface and redistributed on the creping belt to form a web including a plurality of fiber-enriched hollow domed regions protruding from an upper surface of the web, the hollow domed regions having sidewalls being formed along at least a leading edge of the web. Connecting regions form a network interconnecting the hollow domed regions. Transition areas include fibers that transition from the connecting regions into the hollow domed regions, by extending upwardly from the connecting regions into the sidewalls of the domed regions. The web is dried to produce the sheet.

First claim

We claim:

1. A method of making a belt-creped absorbent cellulosic sheet that has an upper surface and a lower surface, the method comprising:
(a) compactively dewatering a papermaking furnish to form a dewatered web having an apparently random distribution of papermaking fiber orientation;
(b) applying the dewatered web having the apparently random distribution of papermaking fiber orientation to a translating transfer surface that is moving at a transfer surface speed;
(c) belt-creping the web from the transfer surface utilizing a polymeric creping belt provided with a plurality of perforations through the creping belt, wherein the web is creped from the transfer surface and redistributed on the creping belt to form a web comprising:
(i) a plurality of fiber-enriched hollow domed regions protruding from the upper surface of the web, the fiber-enriched hollow domed regions having sidewalls being formed along at least a leading edge of the web;
(ii) connecting regions forming a network interconnecting the fiber-enriched hollow domed regions of the web; and
(iii) transition areas comprising consolidated groupings of fibers that transition from the connecting regions into the fiber-enriched hollow domed regions, by extending upwardly from the connecting regions into the sidewalls of the fiber-enriched hollow domed regions; and

(d) drying the web to produce the belt-creped absorbent cellulosic sheet.

2. The method according to claim 1 , further comprising applying a vacuum to the creping belt while the web is held on the belt, in order to expand the web prior to drying the web in the drying step.

3. The method according to claim 1 , wherein the connecting regions have a local basis weight that is lower than a local basis weight of the sidewalls of the fiber-enriched hollow domed regions.

4. The method according to claim 1 , wherein the creping belt has a non-random pattern of perforations.

5. The method according to claim 4 , wherein the non-random pattern of perforations is staggered.

6. The method according to claim 1 , wherein the perforations of the creping belt include tapered perforations, the tapered perforations having openings on a creping side of the belt that are larger than their openings on a machine side of the belt.

7. The method according to claim 1 , wherein the perforations of the creping belt have oval-shaped openings with major axes aligned in the cross-machine direction.

8. The method according to claim 1 , wherein the creping belt has a thickness of from 0.2 mm to 1.5 mm.

9. The method according to claim 1 , wherein the creping belt defines raised lips around openings of the perforations on a creping side of the belt.

10. The method according to claim 9 , wherein the raised lips have a height from the surrounding areas of the belt of from about 10% to 30% of the belt thickness.

11. The method according to claim 1 , wherein the creping belt is of a generally unitary construction made from a polymer sheet selected from one of a solid polymer sheet, a reinforced polymer sheet, and a filled polymer sheet.

12. The method according to claim 1 , wherein the creping belt is made from a monolithic polyester sheet by way of laser drilling.

13. The method according to claim 1 , wherein the sidewalls of the fiber-enriched hollow domed regions have a local basis weight that is higher than a mean basis weight of the sheet.

14. A method of making a belt-creped absorbent cellulosic sheet, the method comprising:
(a) compactively dewatering a papermaking furnish to form a dewatered web having an apparently random distribution of papermaking fiber orientation;
(b) applying the dewatered web having the apparently random distribution of papermaking fiber orientation to a translating transfer surface that is moving at a transfer surface speed;
(c) belt-creping the web from the transfer surface utilizing a polymeric creping belt provided with a plurality of perforations through the creping belt, wherein the web is creped from the transfer surface and redistributed on the creping belt to form a web having a plurality of interconnected regions of different local basis weights including at least:
(i) a plurality of fiber-enriched hollow domed regions having densified caps, the fiber-enriched hollow domed regions projecting from an upper side of the web and having sidewalls;
(ii) connecting regions forming a network interconnecting the fiber-enriched hollow domed regions of the web, the connecting regions having a local basis weight that is lower than a local basis weight of the fiber-enriched hollow domed regions; and
(iii) transition areas that transition from the connecting regions into the fiber-enriched hollow domed regions, by extending upwardly and inwardly from the connecting regions into the sidewalls of the fiber-enriched hollow domed regions; and

(d) drying the web to produce the belt-creped absorbent cellulosic sheet.

15. The method according to claim 14 , further comprising applying a vacuum to the creping belt while the web is held on the belt, in order to expand the web prior to drying the web in the drying step.

16. The method according to claim 14 , wherein the creping belt has a non-random pattern of perforations.

17. The method according to claim 16 , wherein the non-random pattern of perforations is staggered.

18. The method according to claim 14 , wherein the perforations of the creping belt include tapered perforations, the tapered perforations having openings on a creping side of the belt that are larger than their openings on a machine side of the belt.

19. The method according to claim 14 , wherein the perforations of the creping belt have oval-shaped openings with major axes aligned in the cross-machine direction.

20. The method according to claim 14 , wherein the creping belt has a thickness of from 0.2 mm to 1.5 mm.

21. The method according to claim 14 , wherein the creping belt defines raised lips around the openings of the perforations on a creping side of the belt.

22. The method according to claim 21 , wherein the raised lips have a height from the surrounding areas of the belt of from about 10% to about 30% of the belt thickness.

23. The method according to claim 14 , wherein the creping belt is of a generally unitary construction made from a polymer sheet selected from one of a solid polymer sheet, a reinforced polymer sheet, and a filled polymer sheet.

24. The method according to claim 14 , wherein the creping belt is made from a monolithic polyester sheet by way of laser drilling.

25. The method according to claim 14 , wherein the densified caps of the fiber-enriched hollow domed regions have a general shape of a portion of a spheroidal shell.

26. The method according to claim 14 , wherein the densified caps of the fiber-enriched hollow domed regions have a general shape of an apical portion of a spheroidal shell.

27. The method according to claim 14 , wherein the sidewalls of the fiber-enriched hollow domed regions have a local basis weight that is higher than a mean basis weight of the sheet.

28. A method of making a belt-creped absorbent cellulosic sheet, the method comprising:
(A) compactively dewatering a papermaking furnish to form a dewatered web having an apparently random distribution of papermaking fiber orientation;
(B) applying the dewatered web having the apparently random distribution of papermaking fiber

Assignees

• Georgia Pacific Consumer Prod

Inventors

• Super Guy H
• Ruthven Paul J
• Mccullough Stephen J
• Sze Daniel H
• Wendt Greg A
• Miller Joseph H

Classifications

• D21F1/0027

  Screen-cloths · CPC title

• B31F1/126 Primary

  including making of the paper to be crêped · CPC title

• Y10T428/24479

  including variation in thickness · CPC title

• B31F1/122

  the paper being submitted to an additional mechanical deformation other than crêping, e.g. for making it elastic in all directions · CPC title

• D21H27/002

  Tissue paper; Absorbent paper (D21H21/22, D21H27/02, D21H27/20 take precedence; toilet paper A47K10/00; absorbent pads for physiological fluids A61L15/16; making on paper-making machines D21F11/00) · CPC title