Process for the production of nano-fibrillar cellulose gels

Patent metadata

Field	Value
Publication number	US-10975242-B2
Application number	US-201916381484-A
Country	US
Kind code	B2
Filing date	Apr 11, 2019
Priority date	Mar 30, 2009
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

The present invention relates to a process for the production of nano-fibrillar cellulose gels 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 the at least one filler and/or pigment until a gel is formed, as well as the nano-fibrillar cellulose gel obtained by this process and uses thereof.

First claim

The invention claimed is:

1. A process for the production of a nano-fibrillar cellulose gel, characterized by the steps of:
(a) providing cellulose fibres, wherein all or part of the cellulose fibres may be obtained from a recycled pulp;
(b) providing at least one filler and/or pigment;
(c) combining the cellulose fibres and the at least one filler and/or pigment of step (b); and
(d) fibrillating the cellulose fibres in an aqueous environment in the presence of the at least one filler and/or pigment until a nano-fibrillar cellulose gel is formed,
wherein the formation of the gel is verified by monitoring the viscosity of the cellulose fibres in the aqueous environment in the presence of the at least one filler and/or pigment in step (d) in dependence of the shearing rate, wherein the viscosity decrease upon step-wise increase of the shearing rate is stronger than the corresponding viscosity increase upon subsequent step-wise reduction of the shearing rate over at least part of the shear rate range as shearing approaches zero;
wherein the filler is selected from the group consisting of precipitated calcium carbonate (PCC); natural ground calcium carbonate (GCC); dolomite; talc; bentonite; clay; magnesite; satinwhite; sepiolite, huntite, diatomite; silicates; and mixtures thereof; and
wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:33 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 0.5 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 1 to 4 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 from 1.3 to 3 wt-%.

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

9. The process according to claim 8 , wherein the precipitated calcium carbonate comprises a vateritic, a calcitic or an aragonitic crystal structure.

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

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

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

13. The process according to claim 1 , wherein the filler in step (b) is in the form of particles having a medium particle size of from 0.01 to 15 μm.

14. The process according to claim 1 , wherein the filler in step (b) is in the form of particles having a medium particle size of from 0.1 to 10 μm.

15. The process according to claim 1 , wherein the filler in step (b) is in the form of particles having a medium particle size of from 0.3 to 5 μm.

16. The process according to claim 1 , wherein the filler in step (b) is in the form of particles having a medium particle size of from 0.5 to 4 μm.

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- and tartaric acids, salts or esters thereof or mixtures thereof.

19. The process according to claim 1 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:10 to 7:1.

20. The process according to claim 1 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:5 to 5:1.

21. 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.

22. 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.

23. The process according to claim 1 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:1.5 to 1.5:1.

24. The process according to claim 1 , wherein the fibrillating in step (d) is carried out by a homogenizer or an ultra fine friction grinder.

Assignees

• Fiberlean Tech Ltd

Inventors

• Gane Patrick A C
• Schoelkopf Joachim
• Gantenbein Daniel
• Schenker Michel

Classifications

• D21C9/00

  After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters {; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere (polysaccharides, derivatives thereof C08B; paper-making D21B - D21H)} · CPC title

• D21B1/30

  Defibrating by other means · CPC title

• D21B1/04

  by dividing raw materials into small particles, e.g. fibres (breaking-up or cutting wood or the like by dry methods B27L; mechanical separation of fibres from plant material D01B1/00; hackling or heckling machines D01B5/00) · CPC title

• Y02W30/64

  Paper recycling · CPC title

• C08J3/075 Primary

  Macromolecular gels · CPC title