Method for producing modified cellulose

1. A method for producing modified nanofibrillated cellulose, comprising:

preparing a suspension containing fibers from cellulosic material;

adsorbing a cellulose derivative or polysaccharide or polysaccharide derivative onto the fibers in said suspension under special conditions; and

subjecting the fiber suspension comprising said cellulose derivative or polysaccharide or polysaccharide derivative to mechanical disintegration;

to obtain modified nanofibrillated cellulose modified with said cellulose derivative or polysaccharide or polysaccharide derivative.

2. The method according to claim 1 , wherein the cellulosic material is a pulp selected from the group consisting of a chemical pulp, mechanical pulp, thermo mechanical pulp and chemi-thermo mechanical pulp produced from wood, non-wood material or recycled fibers.

3. The method according to claim 2 , wherein wood is from softwood tree, hardwood tree, or a mixture of softwoods and hardwoods.

4. The method according to claim 1 , wherein the cellulose derivative is carboxymethyl cellulose.

5. The method according to claim 2 , wherein the cellulose derivative or polysaccharide or polysaccharide derivative is adsorbed onto the fibers prior to or during mechanical disintegration.

6. The method according to claim 3 , wherein the cellulose derivative or polysaccharide or polysaccharide derivative is adsorbed onto the fibers both prior to and during mechanical disintegration.

7. The method according to claim 1 , wherein the cellulose derivative or polysaccharide or polysaccharide derivative is adsorbed onto the fibers at a temperature of at least 5° C. up to 180° C.

8. The method according to claim 1 , wherein the cellulose derivative or polysaccharide or polysaccharide derivative is adsorbed onto the fibers at a temperature of 75° C.-80° C.

9. The method according to claim 1 , wherein the cellulose derivative or polysaccharide or polysaccharide derivative is adsorbed onto the fibers for at least 1 minute.

10. The method according to claim 1 , wherein the method takes place in the presence of monovalent or polyvalent cations.

11. The method according to claim 1 , wherein the pH value of the fiber suspension is at least pH 2 up to pH 12.

12. The method according to claim 1 , wherein the amount of added cellulose derivative or polysaccharide or polysaccharide derivative is at least 5 mg/g of fiber suspension up to 1000 mg/g of fiber suspension.

13. The method according to claim 1 , wherein mechanical disintegration is carried out with a refiner, grinder, homogenizer, colloider, friction grinder, fluidizer such as microfluidizer, macrofluidizer or fluidizer-type homogenizer.

14. The method according to claim 1 , wherein the fiber suspension is passed through mechanical disintegration at least once.

15. The method according to claim 1 , wherein the fiber suspension containing the cellulose derivative or polysaccharide or polysaccharide derivative is redispersed in water to a concentration of at least 0.1% up to 10% prior to mechanical disintegration.

16. The method according to claim 1 , comprising:

washing the fiber suspension comprising the cellulose derivative, polysaccharide or polysaccharide derivative with water prior to mechanical disintegration.

17. The method according to claim 16 , comprising:

removing the water from the fiber suspension comprising the cellulose derivative, polysaccharide or polysaccharide derivative to form a moist pulp cake prior to mechanical disintegration.

18. The method according to claim 17 , comprising:

redispersing the moist pulp cake in water prior to mechanical disintegration.