Process for increasing the softness of base webs and products made therefrom

• US 20020088592A1
• Filed: 05/11/2001
• Published: 07/11/2002
• Est. Priority Date: 05/12/2000
• Status: Active Grant

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Allen, Peter J., Hermans, Michael A., Arnold, Paul, Drew, Robert A., Riedl, Patricia, Smith, Susan E., Klaubert, Brian, Lin, Phil S.
• Granted Patent: US 6,585,855 B2
• Time in Patent Office: Days
• US Class Current: 162/297
• CPC Class Codes: A61F 13/15707 Mechanical treatment, e.g. notching, twisting, compressing, shaping
• CPC Class Codes: B31F 1/00 Mechanical deformation without removing material, e.g. in combination with laminating
• CPC Class Codes: D21F 1/04 Head boxes of cylinder machines
• CPC Class Codes: D21F 11/006 Making patterned paper
• CPC Class Codes: D21F 11/14 Making cellulose wadding, filter or blotting paper
• CPC Class Codes: D21F 11/145 including a through-drying process
• CPC Class Codes: D21H 11/16 modified by a particular after-treatment
• CPC Class Codes: D21H 25/005 Mechanical treatment D21H25/08, D21H25/18 take precedence
• CPC Class Codes: D21H 27/30 Multi-ply for surface covering D21H27/18; making on paper-making machines D21F9/00, D21F11/00
• CPC Class Codes: D21H 27/38 at least one of the sheets having a fibrous composition differing from that of other sheets
• CPC Class Codes: Y10T 428/24455 Paper
• CPC Class Codes: Y10T 428/24463 Plural paper components

Abstract

A process for increasing the tactile properties of a base web without adversely effecting the strength of the web is disclosed. In one embodiment, the process includes the steps of placing a base web between a first moving conveyor and a second moving conveyor. The conveyors are then wrapped around a shear-inducing roll which creates shear forces that act upon the base web. The shear forces disrupt the web, increasing the softness and decreasing the stiffness of the web. The shear-inducing roll typically has a relatively small diameter. In some applications, more than one shear-inducing roll may be incorporated into the system. Base webs made according to the present invention have been found to have improved void-volume and fuzz-on-edge properties.

Claims

1. A process for producing base webs comprising:

forming a base web containing pulp fibers;

placing said base web between a first moving conveyor and a second moving conveyor;

guiding said first moving conveyor and said second moving conveyor around at least one shear-inducing element while said base web is positioned between said conveyors, said first and second conveyors being sufficiently wrapped around said at least one shear-inducing element so as to create shear forces that act upon the base web and increase the softness of the web.

2. A process as defined in claim 1, wherein said shear-inducing element comprises a roll having a diameter of less than about 10 inches.

3. A process as defined in claim 1, wherein said first and second conveyors are guided around a first support roll prior to said shear-inducing element and around a second support roll after said shear-inducing element, each of said first and second support rolls including a center that is located in a common plane, said shear-inducing element being positioned in between said first and said second support rolls and positioned a preselected distance from said plane.

4. A process as defined in claim 1, wherein said first moving conveyor and said second moving conveyor are guided around at least two shear-inducing elements.

5. A process as defined in claim 1, wherein said base web comprises a stratified web.

6. A process as defined in claim 1, wherein said base web is a stratified web including a middle layer positioned between a first outer layer and a second outer layer, said first and second outer layers having a greater tensile strength than said middle layer.

7. A process as defined in claim 1, wherein said base web is a stratified web including a middle layer positioned between a first outer layer and a second outer layer, said middle layer having a tensile strength greater than said first and second outer layers.

8. A process as defined in claim 1, wherein said base web comprises a single ply web having a basis weight of at least 20 gsm.

9. A process as defined in claim 1, wherein said base web when guided around said shear-inducing element has a moisture content of less than about 10% by weight.

10. A process as defined in claim 1, wherein said first moving conveyor and said second moving conveyor are under a tension of at least 5 pounds per linear inch when guided around said shear-inducing element.

11. A process as defined in claim 1, wherein said first and second conveyors are wrapped around at least 3 shear-inducing elements.

12. A process as defined in claim 1, wherein said first and second conveyors are wrapped around at least 5 shear-inducing elements.

13. A process as defined in claim 1, wherein said first and second conveyors are wrapped around said shear-inducing element at least 30°

.

14. A process as defined in claim 1, wherein said shear-inducing element has an effective diameter of less than about 7 inches.

15. A process as defined in claim 1, wherein said shear-inducing element has an effective diameter of from about 2 inches to about 5 inches.

16. A process as defined in claim 1, wherein said first conveyor and said second conveyor are wrapped around said shear-inducing element at least 50°

.

18. A paper product as defined in claim 17, wherein said base web has a basis weight of greater than 20 gsm.

19. A paper product as defined in claim 17, wherein said base web has a basis weight of greater than 30 gsm.

20. A paper product as defined in claim 17, wherein said paper product comprises a single-ply product.

21. A paper product as defined in claim 17, wherein said base web has a geometric mean tensile strength of greater than about 170 g/in.

22. A paper product as defined in claim 17, wherein said base web has a geometric mean tensile strength of greater than about 200 g/in.

23. A paper product as defined in claim 17, wherein said base web has a fuzz-on-edge of greater than about 2.2 mm/mm.

24. A paper product as defined in claim 17, wherein said base web has a fuzz-on-edge of greater than about 2.5 mm/mm.

25. A paper product as defined in claim 17, wherein said base web has a basis weight of greater than about 25 gsm, has a geometric mean tensile strength of greater than about 170 g/in, and has a fuzz-on-edge of greater than about 2.2 mm/mm.

26. A paper product as defined in claim 17, wherein said base web comprises an uncreped, through-air-dried web.

28. A paper product as defined in claim 27, wherein said base web has a basis weight of greater than 20 gsm.

29. A paper product as defined in claim 28, wherein said base web has a void volume greater than 12 g/g.

30. A paper product as defined in claim 27, wherein said base web has a fuzz-on-edge of greater than about 2.5 mm/mm.

31. A paper product as defined in claim 27, wherein said paper product comprises a single-ply product.

32. A paper product as defined in claim 27, wherein said base web has a geometric mean tensile strength of greater than about 170 g/in.

33. A paper product as defined in claim 27, wherein said base web has a geometric mean tensile strength of greater than about 200 g/in.

34. A paper product as defined in claim 27, wherein said base web comprises an uncreped, through-air-dried web.

36. A process as defined in claim 35, wherein said base web is subjected to said shearing force in an amount sufficient to also increase the fuzz-on-edge properties of the web, said base web having a fuzz-on-edge in an amount of at least 2.2 mm/mm.

37. A process as defined in claim 35, wherein said base web has a moisture content of less than about 10% by weight when subjected to said shearing force.

38. A process as defined in claim 35, wherein said base web comprises a single-ply web, said base web having a basis weight of at least about 20 gsm.

39. A process as defined in claim 35, wherein said base web is subjected to said shearing force by placing said base web in between a first moving conveyor and a second moving conveyor, and guiding said first moving conveyor and said second moving conveyor around a shear-inducing roll while said base web is positioned between said conveyors.

40. A process as defined in claim 39, wherein said first and second conveyors are wrapped around said shear-inducing roll at least 50°

.

17. A paper product comprising:

a nonwoven base web, said base web containing pulp fibers, said base web having a void volume greater than 12 g/g.

27. A paper product comprising:

a nonwoven base web, said base web containing pulp fibers, said base web having a fuzz-on-edge of greater than about 2.2 mm/mm.

35. A process for producing base webs comprising:

forming a base web containing pulp fibers; and

subjecting said base web to a shearing force in an amount sufficient to increase the void volume of said base web, said base web having a void volume of greater than 12 g/g.