Recycling of latex-containing broke

• US 7,364,642 B2
• Filed: 08/18/2003
• Issued: 04/29/2008
• Est. Priority Date: 08/18/2003
• Status: Active Grant

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Anderson, Ralph, Wengeler, William A., Thompson, Tammy
• Primary Examiner(s): Griffin; Steven P.
• Assistant Examiner(s): CORDRAY, DENNIS R
• Application Number:
  US10/643,014
• Publication Number:
  US 20050039868A1
• Time in Patent Office: 1,716 Days
• Field of Search: 162/4, 162/191, 162/55, 162/111, 162/125, 162/169, 162/158, 162/13, 162/20, 162/18, 162/9, 241/21, 241/4
• US Class Current: 162/191
• CPC Class Codes: D21B 1/32 of waste paper
• CPC Class Codes: D21C 5/02 Working-up waste paper mechanical part D21B1/08, D21B1/32
• CPC Class Codes: D21H 11/14 Secondary fibres working-up waste paper D21C5/02
• CPC Class Codes: D21H 17/01 Waste products, e.g. sludge
• 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: Y02W 30/64 Paper recycling

Abstract

Methods for recycling latex-containing broke are generally provided. Specifically, mechanical treatment may be employed to rework latex-containing broke for reuse in various products without the need for treatment with chemicals, such as hypochlorite, chlorine, or hypochlorous acid. As a result of mechanical treatment, fiber aggregates are formed that have a relatively small size. For instance, a large portion of the resulting fiber aggregates may be relatively free from the latex polymer. Specifically, the fiber aggregates can contain a “core” of latex from which extend short fibers and/or fragments that are uncoated with the latex. The result is fiber aggregates that are uniquely “partially coated” with a latex polymer. When recycled in paper products, these fiber aggregates may impart a variety of benefits, such as increased bulk retention and high water capacity without any loss in absorbency rate.

Claims

1. A method comprising mechanically treating broke generated from scrap material accumulated during the production of paper products containing cellulosic fibers and a latex polymer to form fiber aggregates, wherein said latex polymer is present in said broke from about 1% to about 60% by weight, wherein said latex polymer is an adhesive latex, wherein said fiber aggregates have an average size of from about 0.5 to about 6 millimeters, wherein a first portion of said fiber aggregates are coated with said latex polymer and a second portion of said fiber aggregates remain relatively free from said latex polymer, wherein said mechanical treatment comprises pulping said broke in a pulper;

and

forming a paper product that contains said fiber aggregates, wherein said paper product comprises a multi-layered paper web.

2. A method as defined in claim 1, wherein said fiber aggregates have an average size of from about 1 to about 4 millimeters.

3. A method as defined in claim 1, wherein said fiber aggregates have a Canadian Standard Freeness value of from about 400 to about 800.

4. A method as defined in claim 1, wherein said fiber aggregates have a Canadian Standard Freeness value of from about 600 to about 750.

5. A method as defined in claim 1, wherein said second portion constitutes 40% or more of the total area of said fiber aggregates.

6. A method as defined in claim 1, wherein said second portion constitutes 50% or more of the total area of said fiber aggregates.

7. A method as defined in claim 1, wherein said second portion constitutes 60% or more of the total area of said fiber aggregates.

8. A method as defined in claim 1, wherein said broke is diluted to a solids consistency of from about 4% to about 10% prior to said pulping.

9. A method as defined in claim 1, wherein said broke is diluted to a solids consistency of from about 6% to about 8% prior to said pulping.

10. A method as defined in claim 1, wherein said pulper is a rotor/stator type pulper.

11. A method as defined in claim 1, wherein said broke is derived from a product that comprises a multi-layered paper web.

12. A method as defined in claim 11, wherein at least one surface of said product contains said latex polymer in a spaced-apart pattern.

13. A method as defined in claim 12, wherein said latex polymer covers from about 10% to about 70% of said surface.

14. A method as defined in claim 12, wherein said latex polymer covers from about 25% to about 50% of said surface.

15. A method as defined in claim 12, wherein said surface is creped.

16. A method as defined in claim 1, wherein said latex polymer comprises from about 10% to about 40% by weight of said broke.

17. A method as defined in claim 1, wherein said fiber aggregates are incorporated into an inner layer of said multi-layered paper web.

18. A method as defined in claim 17, wherein said fiber aggregates constitute less than about 60% by weight of said inner layer.

19. A method as defined in claim 17, wherein said fiber aggregates constitute from about 10% to about 50% by weight of said inner layer.

20. A method as defined in claim 1, wherein said latex polymer is selected from the group consisting of styrene butadiene, neoprene, polyvinyl chloride, vinyl copolymers, polyamides, ethylene vinyl terpolymers, acrylates, methacrylates, and combinations thereof.

21. A method comprising:

diluting broke to a solids consistency of from about 4% to about 10%, wherein the broke is generated from scrap material accumulated during the production of paper products and contains cellulosic fibers and a latex polymer selected from the group consisting of styrene butadiene, neoprene, polyvinyl chloride, vinyl copolymers, polyamides, ethylene vinyl terpolymers, acrylates, methacrylates, and combinations thereof, wherein said latex polymer is present in said broke from about 1% to about 60% by weight;

pulping said diluted broke;

thereafter refining said broke, wherein said pulping and said refining result in fiber aggregates having an average size of from about 0.5 to about 6 millimeters, and wherein a first portion of said fiber aggregates are coated with said latex polymer and a second portion of said fiber aggregates remain relatively free from said latex polymers, and

forming a paper product that contains said fiber aggregates, wherein said paper product comprises a multi-layered paper web.

22. A method as defined in claim 21, wherein said fiber aggregates have an average size of from about 1 to about 4 millimeters.

23. A method as defined in claim 21, wherein said second portion constitutes 40% or more of the total area of said fiber aggregates.

24. A method as defined in claim 21, wherein said second portion constitutes 60% or more of the total area of said fiber aggregates.

25. A method as defined in claim 21, wherein said broke is diluted to a solids consistency of from about 6% to about 8% prior to said pulping.

26. A method as defined in claim 21, wherein said broke is derived from a product comprising a multi-layered paper web, said product having a surface on which said latex polymer is disposed in a spaced-apart pattern.

27. A method as defined in claim 21, wherein said latex polymer comprises from about 10% to about 40% by weight of said broke.

28. A method comprising mechanically treating broke generated from scrap material accumulated during the production of paper products containing cellulosic fibers and a latex polymer to form fiber aggregates, wherein said latex polymer is present in said broke from about 1% to about 60% by weight, wherein said latex polymer is an adhesive latex polymer, wherein said fiber aggregates have an average size of from about 0.2 to about 12 millimeters and a Canadian Standard Freeness value of from about 400 to about 800, and wherein a first portion of said fiber aggregates are coated with said latex polymer and a second portion of said fiber aggregates remain relatively free from said latex polymer, and

forming a paper product that contains said fiber aggregates, wherein said paper product comprises a multi-layered paper web.

29. A method as defined in claim 28, wherein said fiber aggregates have an average size of from about 0.5 to about 6 millimeters.

30. A method as defined in claim 28, wherein said fiber aggregates have an average size of from about 1 to about 4 millimeters.

31. A method as defined in claim 28, wherein said fiber aggregates have a Canadian Standard Freeness value of from about 600 to about 750.

32. A method as defined in claim 28, wherein said second portion constitutes 40% or more of the total area of said fiber aggregates.

33. A method as defined in claim 28, wherein said second portion constitutes 60% or more of the total area of said fiber aggregates.

34. A method as defined in claim 28, wherein said mechanical treatment comprises pulping said broke in a pulper.

35. A method as defined in claim 34, wherein said broke is diluted to a solids consistency of from about 4% to about 10% prior to said pulping.

36. A method as defined in claim 34, wherein said pulper is a rotor/stator type pulper.

37. A method as defined in claim 34, wherein said mechanical treatment further comprises refining said broke.

38. A method as defined in claim 28, wherein said broke is derived from a product that comprises a multi-layered paper web.

39. A method as defined in claim 38, wherein at least one surface of said product contains said latex polymer in a spaced-apart pattern.

40. A method as defined in claim 39, wherein said surface is creped.

41. A method as defined in claim 28, wherein said latex polymer comprises from about 10% to about 40% by weight of said broke.

42. A method as defined in claim 28, wherein said fiber aggregates are incorporated into an inner layer of said multi-layered paper web.