Patent ID: 9409998
Filing Date: 2016-08-09
CPC Classification: C08B,C08L,D21H

Claim Text:
1. A method for processing anionically charged fibril cellulose which is nanofibrillar cellulose derivative containing additional functional groups making the cellulose anionically charged, manufactured from wood fiber and wherein the fibrils have a maximum diameter of 50 nm and which derivative is in the form of aqueous viscoelastic fibril cellulose hydrogel, the method comprising lowering the pH of the aqueous fibril cellulose hydrogel below the pKa value of the anionically charged fibril cellulose to pH 2-3 to provide aqueous fibril cellulose hydrogel of reduced water retention capacity, and dewatering the aqueous fibril cellulose hydrogel of reduced water retention capacity in a pressure filtration step where positive pressure is applied to the aqueous fibril cellulose hydrogel to provide dewatered fibril cellulose.