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

Patent metadata

Field	Value
Publication number	US-9926665-B2
Application number	US-201615067760-A
Country	US
Kind code	B2
Filing date	Mar 11, 2016
Priority date	Feb 25, 2016
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

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:
forming a pulp from a cellulosic feedstock;
bleaching the pulp;
crosslinking 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 bleaching the pulp includes bleaching the pulp according to a Kraft bleaching process.

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

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

6. 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.

7. 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.

8. 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.

9. 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.

10. 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.

11. 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.

12. The method of claim 1 , further comprising, prior to drying the pulp, 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.

Assignees

• Int Paper Co

Inventors

• Luo Mengkui

Classifications

• C08B15/10 Primary

  Crosslinking of cellulose · CPC title

• D21H11/14

  Secondary fibres (working-up waste paper D21C5/02) · CPC title

• D21H13/04

  Cellulose ethers · CPC title

• D21C9/005 Primary

  organic compounds · CPC title

• C08L2312/00

  Crosslinking · CPC title