Method for pretreating cellulose pulp

Patent metadata

Field	Value
Publication number	US-9725849-B2
Application number	US-201615065203-A
Country	US
Kind code	B2
Filing date	Mar 9, 2016
Priority date	Feb 10, 2012
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

The invention relates to pretreating of native cellulose pulp in the manufacture of nanofibrillated cellulose, and to a nanofibrillated cellulose product obtainable by the method.

First claim

The invention claimed is:

1. A nanofibrillated cellulose product obtainable by the method comprising:
pretreating native cellulose pulp, the pretreating comprising
bringing an aqueous suspension of the native cellulose pulp into contact with an inorganic or organic acid,
agitating the aqueous suspension of native cellulose pulp and inorganic or organic acid to obtain a pH below about 4,
removing water from the aqueous suspension of native cellulose pulp and inorganic or organic acid to obtain solid matter,
washing the solid matter with water, thereby forming an aqueous suspension of the solid matter,
adding at least one water soluble salt of NH4+, alkali metal or alkaline earth metal or metal to the aqueous suspension of the solid matter,
agitating the aqueous suspension of the solid matter,
adjusting the pH of the aqueous suspension of the solid matter to about 7.5 to about 12 using an inorganic base,
removing water to yield solid matter of the aqueous suspension of the solid matter, and
washing the solid matter of the aqueous suspension of the solid matter with distilled or deionized water to yield pretreated native cellulose pulp;

forming an aqueous suspension of the pretreated native cellulose pulp; and
disintegrating the aqueous suspension of native cellulose pulp mechanically via more than one pass through a mechanical disintegration device,
wherein the product includes native cellulose and has a turbidity of less than about 200 NTU at about 0.1% concentration and a Brookfield viscosity of more than about 15,000 mPas at about 1.5% concentration.

2. The nanofibrillated cellulose product of claim 1 , wherein the product has a turbidity of less than about 150 NTU at about 0.1% concentration.

3. The nanofibrillated cellulose product of claim 1 , wherein the product has Brookfield viscosity of more than about 30,000 mPas at about 1.5% concentration.

4. The nanofibrillated cellulose product of claim 1 , wherein the product has gelling properties.

5. The nanofibrillated cellulose product of claim 1 , wherein the product includes less than about 5,000 particles.

6. The nanofibrillated cellulose product of claim 1 , wherein the product is substantially free of salts.

7. The nanofibrillated cellulose product of claim 1 , wherein the product includes fewer impurities than the native cellulose pulp.

8. The nanofibrillated cellulose product of claim 1 , wherein the more than one pass is between two and ten passes.

9. The nanofibrillated cellulose product of claim 1 , wherein the product is generally transparent.

10. The nanofibrillated cellulose product of claim 1 , wherein the pretreated native cellulose pulp is in M+ form of native cellulose pulp, wherein M is an alkali metal, an alkaline earth metal, or a metal.

11. The nanofibrillated cellulose product of claim 10 , wherein the pretreated native cellulose pulp is a metal, wherein the metal is Na, K, Li, Cu, or Ag.

Assignees

• Upm Kymmene Corp

Inventors

• Nuopponen Markus
• Osterberg Monika
• Laine Janne
• Pere Jaakko

Classifications

• D21B1/063 Primary

  using grinding devices · CPC title

• D21C9/007

  by mechanical or physical means · CPC title

• D21C3/26

  Multistage processes · CPC title

• D21H11/10

  Mixtures of chemical and mechanical pulp · CPC title

• D21C9/18

  De-watering (de-watering in general F26B); {Elimination of cooking or pulp-treating liquors from the pulp}(D21C9/002, D21C9/02 take precedence; paper-making machines D21F; strainers in digesters D21C7/00; presses in general B30B) · CPC title