Crosslinked cellulose as precursor in production of high-grade cellulose derivatives and related technology

Patent metadata

Field	Value
Publication number	US-10428459-B2
Application number	US-201815909848-A
Country	US
Kind code	B2
Filing date	Mar 1, 2018
Priority date	Feb 25, 2016
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

A pulp in accordance with a particular embodiment includes crosslinked cellulose fibers. The pulp can have high brightness, reactivity, and intrinsic viscosity. The pulp, therefore, can be well suited for use as a precursor in the production of low-color, high-viscosity cellulose derivatives. A method in accordance with a particular embodiment of the present technology includes forming a pulp from a cellulosic feedstock, bleaching the pulp, crosslinking cellulose fibers within the pulp while the pulp has a high consistency, and drying the pulp. The bleaching process can reduce a lignin content of the pulp to less than or equal to 0.09% by oven-dried weight of the crosslinked cellulose fibers. Crosslinking the cellulose fibers can include exposing the cellulose fibers to a glycidyl ether crosslinker having two or more glycidyl groups and a molecular weight per epoxide within a range from 140 to 175.

First claim

What is claimed is:

1. A method, comprising:
bleaching a pulp comprising cellulose fibers;
crosslinking the cellulose fibers within the pulp while the pulp has a consistency greater than or equal to 12%; and
drying the pulp after bleaching the pulp and after crosslinking the cellulose fibers, wherein the dried pulp has:
a resultant carboxymethyl cellulose viscosity greater than or equal to 60 centipoise,
a brightness greater than or equal to 75%, and
a water retention value greater than or equal to 1.1 g/g.

2. The method of claim 1 , wherein crosslinking the cellulose fibers includes crosslinking the cellulose fibers while the pulp has a consistency greater than or equal to 15%.

3. The method of claim 1 , wherein crosslinking the cellulose fibers includes increasing a water retention value of the pulp by crosslinking the crosslinking the cellulose fibers.

4. The method of claim 1 , wherein crosslinking the cellulose fibers includes exposing the cellulose fibers to a glycidyl ether crosslinker having two or more glycidyl groups.

5. The method of claim 1 , wherein crosslinking the cellulose fibers includes exposing the cellulose fibers to a crosslinker, and wherein the crosslinker has a weight average molecular weight within a range from 174 to 500.

6. The method of claim 1 , wherein crosslinking the cellulose fibers includes exposing the cellulose fibers to a crosslinker, and wherein the crosslinker has a molecular weight per epoxide within a range from 140 to 175.

7. The method of claim 1 , wherein crosslinking the cellulose fibers includes exposing the cellulose fibers to a crosslinker, and wherein the crosslinker includes a first glycidyl group, a second glycidyl group, and either three or four linear chain carbon atoms between the first and second glycidyl groups.

8. The method of claim 1 , further comprising blending the pulp with a dissolving grade pulp having a cellulose content greater than 90% by oven dried weight to form a blended pulp after crosslinking the cellulose fibers, wherein drying the pulp includes drying the blended pulp.

9. The method of claim 1 , wherein bleaching the pulp includes bleaching a Kraft pulp.

10. The method of claim 1 , wherein bleaching the pulp includes oxygen bleaching the pulp.

11. The method of claim 1 , wherein bleaching the pulp includes chlorine dioxide bleaching the pulp after oxygen bleaching the pulp.

12. The method of claim 1 , wherein bleaching the pulp includes increasing a brightness of the pulp to a brightness greater than or equal to 75%.

13. The method of claim 1 , wherein bleaching the pulp includes reducing a lignin content of the pulp to less than or equal to 0.09% by oven-dried weight of the crosslinked cellulose fibers.

Assignees

• Int Paper Co

Inventors

• Luo Mengkui

Classifications

• C08B15/10 Primary

  Crosslinking of cellulose · CPC title

• D21H13/04

  Cellulose ethers · CPC title

• C08H8/00

  Macromolecular compounds derived from lignocellulosic materials {(pretreatment thereof B27N)} · CPC title

• D21C9/18

  De-watering (de-watering in general F26B); {Elimination of cooking or pulp-treating liquors from the pulp}(D21C9/002, D21C9/02 take precedence; paper-making machines D21F; strainers in digesters D21C7/00; presses in general B30B) · CPC title

• D21H11/04 Primary

  Kraft or sulfate pulp · CPC title