Modified fiber from shredded pulp sheets, methods, and systems

Patent metadata

Field	Value
Publication number	US-10156042-B2
Application number	US-201514983402-A
Country	US
Kind code	B2
Filing date	Dec 29, 2015
Priority date	Dec 29, 2015
Publication date	Dec 18, 2018
Grant date	Dec 18, 2018

Abstract

Methods of forming crosslinked cellulose include mixing a crosslinking agent with cellulose mat fiber fragments composed of hydrogen-bonded cellulose fibers and having a solids content of about 45-95% to form a substantially homogenous mixture of non-crosslinked, individualized cellulose fibers, drying the resulting mixture to 85-100% solids, then curing the dried mixture under conditions effective to crosslink the cellulose fibers. Some of such methods may include fragmenting a cellulose fiber mat to form the mat fragments. Systems include a mixing unit (such as a high-consistency mixer) configured to form, from the mat fragments and a crosslinking agent, a substantially homogenous mixture of non-crosslinked, individualized cellulose fibers and crosslinking agent, at ambient conditions, a drying unit to dry the substantially homogenous mixture to a consistency of 85-100%, and a curing unit and to cure the crosslinking agent to form dried and cured crosslinked cellulose fibers.

First claim

The invention claimed is:

1. A method of forming a crosslinked cellulose product, comprising:
mixing a crosslinking agent with cellulose fiber mat fragments, the cellulose fiber mat fragments comprising hydrogen-bonded cellulose fibers and having a solids content of about 45-95%, and the crosslinking agent being added in an amount suitable to achieve a desired level of crosslinking of the cellulose fibers, in individualized form, based on the solids content, wherein the mixing forms a substantially homogenous mixture of non-crosslinked, individualized cellulose fibers and the crosslinking agent;
drying the resulting mixture to 85-100% solids; and
curing the dried mixture under conditions effective to crosslink the cellulose fibers.

2. The method of claim 1 , wherein the cellulose fiber mat fragments have a solids content of about 60-80%.

3. The method of claim 1 , further comprising, prior to mixing, fragmenting a cellulose fiber mat to form the cellulose fiber mat fragments.

4. The method of claim 3 , wherein fragmenting further comprises moistening the cellulose fiber mat prior to forming the cellulose fiber mat fragments.

5. The method of claim 3 , wherein fragmenting further comprises one or more of shredding, cutting, or dicing the cellulose fiber mat.

6. The method of claim 3 , wherein the cellulose fiber mat is one or more of the following: pulp sheet, paper, paperboard, nonwoven, and wet lap sheet consisting of never dried or previously dried cellulose.

7. The method of claim 3 , wherein fragmenting includes passing the cellulose mat in bale or roll form to a crusher, dicer, and/or shredder.

8. The method of claim 1 , wherein mixing includes adding the crosslinking agent in an amount sufficient to achieve a chemical on pulp range of about 2-14%.

9. The method of claim 1 , wherein mixing is performed at ambient conditions.

10. The method of claim 1 , wherein mixing includes setting the solids content of the mixture of the crosslinking agent and the cellulose fiber mat fragments to about 40-60%.

11. The method of claim 10 , wherein setting the solids content of the mixture includes setting the crosslinking agent to a concentration suitable to achieve said solids content.

12. The method of claim 10 , wherein mixing includes setting the solids content of the mixture of the crosslinking agent and the cellulose fiber mat fragments to about 50-60%.

13. The method of claim 1 , wherein mixing is performed in one or more of an extruder, a hydrapulper, a refiner, a deflaker, and a high-consistency mixer.

14. The method of claim 1 , wherein the cellulose fiber mat fragments consist essentially of hydrogen-bonded cellulose fibers.

15. A method of forming a crosslinked cellulose product, comprising:
fragmenting a hydrogen-bonded mat of cellulose fibers to form cellulose fiber mat fragments having a solids content of about 60-80%;
mixing a polyacrylic acid crosslinking agent with the cellulose fiber mat fragments in an amount and concentration to achieve a chemical on pulp level of about 2-14% and a solids content of the mixture of crosslinking agent and the cellulose fiber mat fragments of about 50-60%, wherein said mixing is done at ambient conditions, and wherein said mixing individualizes the cellulose fibers;
drying the resulting mixture to 85-100% solids; and
curing the dried mixture under conditions effective to crosslink the cellulose fibers.

Assignees

• Int Paper Co

Inventors

• Miller Charles E
• Lovas Alan D

Classifications

• D21C9/001

  Modification of pulp properties (purification D21C9/08) · CPC title

• D21H15/02

  characterised by configuration · CPC title

• D21H13/06

  Cellulose esters · CPC title

• D21C9/002 Primary

  by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives · CPC title

• D21C9/007

  by mechanical or physical means · CPC title