Nanofibrillated cellulose (NFC) is typically obtained by mechanical disintegration of cellulose pulp, carried out with suitable disintegration equipment. Mechanical disintegration is an energy consuming operation where the production capacity is limited. Thus several measures have been proposed for improving the grinding or fibrillation process, such as modification of pulp prior to the disintegration. Said modification may comprise chemical modification of the pulp to yield anionically or cationically charged grades of nanofibrillated cellulose (NFC). Said chemical modification may be based for example on carboxymethylation, oxidation, esterification, or etherification of cellulose molecules. However, said chemical modification methods result in grades of NFC, which are not desirable for all applications and thus also alternative methods have been studied, such as pregrinding, carboxymethylcellulose adsorption and enzymatic treatment.
Accordingly, there exists a need to provide improved methods for the preteatment of pulp in the manufacture of NFC and improved methods for the manufacture of NFC.
USPTO Backgrounds
USPTO Backgrounds