High yield and enhanced performance fiber

Patent metadata

Field	Value
Publication number	US-10000889-B2
Application number	US-201514679604-A
Country	US
Kind code	B2
Filing date	Apr 6, 2015
Priority date	Jun 12, 2007
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

A method of wood pulping having a significantly increased yield is disclosed. Wood chips are chemically pulped to a high kappa number, providing a first accepts component and a first rejects component. The first rejects component is subjected to a high consistency pulping process such as a substantially mechanical pulping process to generate a second accepts component and a second rejects component. The first accepts component may be used in the production of saturating kraft paper with excellent saturability and resin pick up. The second accepts may be used as a second fiber source in the production of multiply linerboard and unbleached paperboard with enhanced stiffness, strength, and smoothness. Alternatively, the first accepts component may be blended with the second accepts component to produce fiber blends, which may be used in a production of paper-based products having enhanced strength and stiffness at low basis weight.

First claim

The invention claimed is:

1. A method of wood pulping, comprising steps of:
(a) chemically pulping hardwood chips by kraft pulping to a kappa number of not less than 30 to generate a first amount of pulp including a first accepts component and a first rejects component wherein the ratio of the weight of the first rejects component to the weight of the first amount of pulp comprises about 20% to about 50%;
(b) separating the first accepts component from the first rejects component;
(c) thickening the separated first rejects component;
(d) performing a high consistency, substantially mechanical pulping of the thickened first rejects component to generate a second amount of pulp including a second accepts component and a second rejects component, wherein the high consistency, substantially mechanical pulping is performed in the presence of an alkaline material;
(e) separating the second accepts component from the second rejects component;
(f) combining the first and the second accepts components to create a fiber blend; and
(g) oxidative bleaching the fiber blend with at least one of elemental chlorine, chlorine dioxide, ozone, and hypochlorite.

2. The method of claim 1 , wherein the ratio of the weight of the first rejects component to the weight of the first amount of pulp comprises about 30% to about 35%.

3. The method of claim 1 , wherein the separating step in step (b) comprises a step of passing the first amount of pulp through a screen to separate the first accepts component from the first rejects component.

4. The method of claim 1 , wherein the high consistency, substantially mechanical pulping comprises a pulping process selected from the group consisting of mechanical pulping, alkaline peroxide mechanical pulping, alkaline thermo mechanical pulping, thermo mechanical pulping, and chemi-thermomechanical pulping.

5. The method of claim 1 , wherein the high consistency, substantially mechanical pulping comprises a pulping process selected from the group consisting of alkaline peroxide mechanical pulping and alkaline thermo mechanical pulping.

6. The method of claim 1 , wherein the kraft pulping includes a chemical additive selected from the group consisting of anthraquinone, polysulfide, penetrating aids, thiourea, and combinations thereof.

7. The method of claim 1 , wherein the high consistency, substantially mechanical pulping comprises steps of:
(8.1) refining the first rejects component; and
(8.2) pre-bleaching the first rejects component.

8. The method of claim 1 , wherein the high consistency, substantially mechanical pulping comprises steps of:
(9.1) refining the first rejects component;
(9.2) pre-bleaching the first rejects component; and
(9.3) retaining the first rejects component treated at the steps (9.1) and (9.2) for a predetermined time period.

9. The method of claim 1 , wherein the separating step in step (e) comprises a step of passing the second amount of pulp through a screen to separate the second accepts component from the second rejects component.

10. The method of claim 1 , further comprising a step of combining the second rejects component with the first rejects component before further processing.

11. The method of claim 1 , wherein the ratio of the weight of the first accepts component to the weight of the fiber blend comprises about 50% to about 90%.

12. The method of claim 1 , wherein the ratio of the weight of the first accepts component to the weight of the fiber blend comprises about 65% to about 75%.

13. The method of claim 1 , further comprising a step of processing the fiber blend for a production of a paper-based product.

14. A method of wood pulping, comprising steps of:
(a) chemically processing hardwood chips by kraft pulping to a kappa number of not less than 30 to produce a first amount of pulp including a first accepts component and a first rejects component, wherein the first rejects component comprises more than 30% of the first amount of pulp;
(b) separating the first accepts component from the first rejects component;
(c) thickening the separated first rejects component;
(d) performing a high consistency, substantially mechanical pulping of the thickened first rejects component to generate a second amount of pulp including a second accepts component and a second rejects component, wherein the high consistency, substantially mechanical pulping is performed in the presence of an alkaline material;
(e) separating the second accepts component from the second rejects component;
(f) combining the first and the second accepts components to create a fiber blend; and
(g) oxidative bleaching the fiber blend with at least one of elemental chlorine, chlorine dioxide, ozone, and hypochlorite.

15. The method of claim 14 , wherein the separating step in step (b) comprises a step of passing the first amount of pulp through a screen to separate the first accepts component from the first rejects component.

16. The method of claim 14 , wherein the high consistency, substantially mechanical pulping comprises a pulping process selected from the group consisting of mechanical pulping, alkaline peroxide mechanical pulping, alkaline thermo mechanical pulping, thermo mechanical pulping, and chemi-thermomechanical pulping.

17. The method of claim 14 , wherein the high consistency, substantially mechanical pulping comprises a pulping process selected from the group consisting of alkaline peroxide mechanical pulping and alkaline thermo mechanical pulping.

18. The method of claim 14 , wherein the high consistency, substantially mechanical pulping comprises steps of:
(24.1) refining the first rejects component; and
(24.2) pre-bleaching the first rejects component.

19. The method of claim 14 , wherein the high consistency, substantially mechanical pulping comprises steps of:
(25.1) refining the first rejects component;
(25.2) pre-bleaching the first rejects component; and
(25.3) retaining the first rejects component treated at the steps (25.1) and (25.2) for a predetermined time period.

20. The method of claim 14 , wherein the separating step in step (e) comprises a step of passing the second amount of pulp through a screen to separate the second accepts component from the second rejects component.

21. The method of claim 14 , further comprising a step of combining the second rejects component with the first rejects component before further processing.

22. The method of claim 14 , wherein the ratio of the weight of the first accepts component to the weight of the fiber blend comprises about 50% to about 90%.

23. The method of claim 14 , wherein the ratio of the weight of the first accepts component to the weight of the fiber blend comprises about 65% to about 75%.

24. The method of claim 14 , further comprising a step of processing the fiber blend for a production of a paper-based product.

25. A method of wood pulping comprising steps of:
(a) chemically pulping hardwood chips by kraft pulping to a kappa number of not less than 50 to generate a first amount of pulp including a first accepts component and a first rejects component;
(b) separating the first accepts component from the first rejects component;
(c) thickening the separated first rejects component;
(d) substantially mechanically pulping the thickened first rejects component at a high consistency to generate a second amount of pulp including a second accepts component and a second rejects component, wherei

Assignees

• Westrock Mwv Llc

Inventors

• Hart Peter W
• Waite Darrell M
• Nutter Jr Dale E
• Bradberry Jared

Classifications

• D21D5/02

  Straining or screening the pulp · CPC title

• D21C3/222

  Use of compounds accelerating the pulping processes · CPC title

• D21D1/20

  Methods of refining · CPC title

• D21C3/26

  Multistage processes · CPC title

• D21H27/30

  Multi-ply (for surface covering D21H27/18; making on paper-making machines D21F9/00, D21F11/00) · CPC title