Method for producing nanofibrillar cellulose and nanofibrillar cellulose product

Patent metadata

Field	Value
Publication number	US-10697116-B2
Application number	US-201515125343-A
Country	US
Kind code	B2
Filing date	Mar 27, 2015
Priority date	Mar 31, 2014
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

In a method for producing nanofibrillar cellulose, cellulose based fibre material, in which internal bonds in cellulose fibres have been weakened by preliminary modification of cellulose, is subjected to disintegration treatment in form of pulp comprising fibres and liquid. The fibre material is supplied at a consistency higher than 10 wt-%, preferably at least 15 wt-%, to a disintegration treatment where fibrils are detached from the fibre material by joint effect of repeated impacts to the fibre material by fast moving successive elements and the weakened internal bonds of the cellulose fibres. The nanofibrillar cellulose is withdrawn from the disintegration treatment at dry matter which is equal or higher than the consistency of the fibre material. In the disintegration treatment, the fibre material is supplied through several counter-rotating rotors (R 1 , R 2 , R 3 . . . ) outwards in the radial direction with respect to the rotation axis (RA) of the rotors in such a way that the material is repeatedly subjected to shear and impact forces by the effect of the blades ( 1 ) of the different counter-rotating rotors.

First claim

The invention claimed is:

1. A method for producing nanofibrillar cellulose, wherein cellulose based fibre material, in which internal bonds in cellulose fibres have been weakened by preliminary chemical modification of cellulose, is subjected to disintegration treatment in form of pulp suspension comprising fibres and liquid wherein the fibre material supplied to the disintegration treatment has one of the following properties:
oxidized cellulose having carboxylate content of at least 0.8 mmol/g pulp or higher,
carboxymethylated cellulose having degree of substitution above 0.1, or
cationized cellulose having degree of substitution of at least 0.1 or higher, said method comprising:
supplying the pulp suspension at a consistency higher than 10 wt-% based on the proportion of the fibres in the pulp suspension and having a content of gas of greater than 10 volume percent, to a disintegration treatment
detaching fibrils from the fibre material in course of said disintegration treatment by joint effect of repeated impacts to the fibre material by fast moving successive elements and the weakened internal bonds of the cellulose fibres, wherein the fibre material is subjected to repeated impacts successively from opposite directions; and
withdrawing the nanofibrillar cellulose from the disintegration treatment at dry matter which is equal or higher than the consistency of the fibre material.

2. The method according to claim 1 , wherein the fibre material is supplied at a consistency of higher than 15 wt-% and 50 wt-% at most.

3. The method according to claim 1 , wherein the cellulose in the fibre material supplied to the disintegration treatment is ionically charged cellulose.

4. The method according to claim 3 , wherein the fibre material supplied to the disintegration treatment has the following properties:
cellulose modified physically by adsorbing anionic or cationic substances on cellulose surface in an amount of 20-1000 mg/g.

5. The method according to claim 3 , wherein the fibre material supplied to the disintegration treatment has the following properties:
oxidized cellulose having carboxylate content of 0.8-1.8 mmol/g pulp,
carboxymethylated cellulose having degree of substitution of 0.12-0.2, or
cationized cellulose having degree of substitution of 0.1-0.6.

6. The method according to claim 1 , wherein the cellulose in the fibre material supplied to the disintegration treatment is enzymatically modified cellulose.

7. The method according to claim 1 , wherein the disintegration treatment, the fibre material is supplied through several counter-rotating rotors (R 1 , R 2 , R 3 . . . ) outwards in the radial direction with respect to the rotation axis (RA) of the rotors in such a way that the material is repeatedly subjected to shear and impact forces by the effect of the blades (1) of the different counter-rotating rotors, whereby it is simultaneously fibrillated, wherein the fibrillation is effected by means of impact energy utilizing a series of frequently repeated impacts having varying directions of action caused by several successive impacts from opposite directions.

8. The method according to claim 1 , wherein the disintegration treatment is continued until the nanofibrillar cellulose withdrawn from the disintegration treatment has achieved a zero shear viscosity of 1,000 to 50,000 Pa·s and a yield stress of 1 to 50 Pa when measured at a consistency of 0.5%.

9. The method according to claim 1 , wherein the fibre material in form of pulp is subjected to the disintegration treatment together with a gaseous medium.

10. The method according to claim 1 , wherein the nanofibrillar cellulose is packed and delivered in the same dry matter content as it was withdrawn from the disintegration treatment.

11. The method according to claim 10 , wherein the dry matter content of the nanofibrillar cellulose, based on the dry matter of nanofibrils, is 16-60 wt-%.

12. The method according to claim 1 , wherein after the nanofibrillar cellulose has been withdrawn from the disintegration treatment, its dry matter content is raised, and the nanofibrillar cellulose is packed and delivered in a higher dry matter content than the dry matter content in which it was withdrawn from the disintegration treatment.

13. The method of claim 1 , wherein the internal bonds in the cellulose fibres have been weakened by a preliminary chemical modification of cellulose.

14. The method according to claim 1 , wherein the fibre material is supplied at a consistency of 15-40 wt-%.

Assignees

• Upm Kymmene Corp

Inventors

• Nuopponen Markus
• Tamper Juha
• Kajanto Isko

Classifications

• D21D1/36 Primary

  with vertical shaft · CPC title

• D21H11/18

  Highly hydrated, swollen or fibrillatable fibres · CPC title

• D21H11/20 Primary

  Chemically or biochemically modified fibres · CPC title

• D21B1/14 Primary

  Disintegrating in mills · CPC title