Process for the production of nano-fibrillar cellulose suspensions

Patent metadata

Field	Value
Publication number	US-10982387-B2
Application number	US-201916381754-A
Country	US
Kind code	B2
Filing date	Apr 11, 2019
Priority date	Mar 30, 2009
Publication date	Apr 20, 2021
Grant date	Apr 20, 2021

Abstract

The present invention relates to a process for the production of suspensions of nano-fibrillar cellulose by providing cellulose fibres and at least one filler and/or pigment; combining the cellulose fibres and the at least one filler and/or pigment; and fibrillating the cellulose fibres in the presence of at least one filler and/or pigment, as well as the suspensions of nano-fibrillar cellulose obtained by this process and their uses.

First claim

The invention claimed is:

1. A process for the production of a nano-fibrillar cellulose suspension comprising the steps of:
(a) providing cellulose fibres, wherein all or part of the cellulose fibres may be obtained from a recycled pulp;
(b) providing a filler; wherein the filler is selected from the group consisting of precipitated calcium carbonate (PCC); natural ground calcium carbonate (GCC); dolomite; talc; bentonite; clay; magnesite; satin white; sepiolite, huntite, diatomite; silicates; and mixtures thereof;
(c) combining the cellulose fibres from step (a) and the filler from step (b); and
(d) fibrillating the cellulose fibres and the filler from step (c) to obtain a nano-fibrillar cellulose suspension,
wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:10 to 10:1.

2. The process according to claim 1 , wherein the cellulose fibres in step (a) are provided in the form of a suspension.

3. The process according to claim 2 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 0.2 to 35 wt-%.

4. The process according to claim 2 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 0.25 to 10 wt-%.

5. The process according to claim 2 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 1 to 5 wt-%.

6. The process according to claim 2 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 2 to 4.5 wt-%.

7. The process according to claim 2 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of about 1.3 or about 3.5 wt-%.

8. The process according to claim 1 , wherein the filler in step (b) is precipitated calcium carbonate.

9. The process according to claim 1 , wherein the filler in step (b) is precipitated calcium carbonate having a vateritic, a calcitic or an aragonitic crystal structure.

10. The process according to claim 1 , wherein the filler in step (b) is natural ground calcium carbonate.

11. The process according to claim 1 , wherein the filler in step (b) is natural ground calcium carbonate selected from marble, limestone and/or chalk.

12. The process according to claim 1 , wherein the precipitated calcium carbonate in step (b) is ultrafine discrete prismatic, scalenohedral or rhombohedral precipitated calcium carbonate.

13. The process according to claim 1 , wherein the filler in step (b) is in the form of particles having a median particle size of from 0.03 to 15 um.

14. The process according to claim 1 , wherein the filler in step (b) is in the form of particles having a median particle size of from 0.2 to 5 μm.

15. The process according to claim 1 , wherein the filler in step (b) is in the form of particles having a median particle size of from 0.2 to 4 μm.

16. The process according to claim 1 , wherein the filler particles in step (b) is in the form of particles having a median particle size of about 1.5 or about 3.2 um.

17. The process according to claim 1 , wherein the filler in step (b) comprises a dispersing agent.

18. The process according to claim 17 , wherein the dispersing agent is selected from homopolymers or copolymers of polycarboxylic acids and/or their salts or esters, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, acryl amide or acrylic esters, or mixtures thereof; alkali polyphosphates, phosphonic-, citric- or tartaric acids, salts or esters thereof; or mixtures thereof.

19. The process according to claim 1 , wherein before fibrillating in step (d), the pH of the combination of the cellulose fibres and the filler is adjusted to a pH of 10 to 12.

20. The process according to claim 1 , wherein after fibrillating in step (d), the pH of the suspension is re-adjusted to a pH of 7.5 to 9.5.

21. The process according to claim 1 , wherein after fibrillating in step (d), the pH of the suspension is re-adjusted to a pH of about 8.5.

22. The process according to claim 1 , wherein the combination resulting from step (c) is stored for 2 to 12 hours prior to fibrillating in step (d).

23. The process according to claim 1 , wherein the combination resulting from step (c) is stored for 3 to 10 hours, prior to fibrillating in step (d).

24. The process according to claim 1 , wherein the combination resulting from step (c) is stored for 4 to 8 hours, prior to fibrillating in step (d).

25. The process according to claim 1 , wherein a cellulose solvent is added to the combination in step (c) prior to fibrillating in step (d).

26. The process according to claim 1 , wherein the cellulose solvent is copper(II)ethylenediamine, iron-sodium-tartrate or lithium-chloride/dimethylacetamine.

27. The process according to claim 1 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:6 to 6:1.

28. The process according to claim 1 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:4 to 4:1.

29. The process according to claim 1 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:3 to 3:1.

30. The process according to claim 1 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:2 to 2:1.

Assignees

• Fiberlean Tech Ltd

Inventors

• Gane Patrick A C
• Schoelkopf Joachim
• Gantenbein Daniel
• Schenker Michel
• Pohl Michael
• Kübler Beat

Classifications

• Y02W30/64

  Paper recycling · CPC title

• D21H11/16

  modified by a particular after-treatment · CPC title

• D21H11/18 Primary

  Highly hydrated, swollen or fibrillatable fibres · CPC title

• D21D1/00

  Methods of beating or refining; Beaters of the Hollander type (knotter screens D21F) · CPC title

• D21H15/04

  crimped, kinked, curled or twisted fibres · CPC title