Patent ID: 9441052
Filing Date: 2016-09-13
CPC Classification: C08B,C08L,D21C,D21H

Claim Text:
1. A method for manufacturing nanofibrillar cellulosic material, the method comprising: introducing cellulose fibers as cellulosic raw material to a system, and conveying the cellulose fibers to an extruder comprising a mixing part and optionally a refining part, wherein the method further comprises: dosing at least one first chemical comprising an alkalizing agent in an amount between 2 and 20% from the used cellulose raw material to the system before the extruder and/or in the extruder and performing a reaction between the cellulose fibers and the first chemical(s) at least partly in the extruder to activate the fibers, wherein the reaction is performed with a dry matter content of the cellulose material of at least 40%, and then dosing at least one second chemical comprising a carboxymethylating agent in an amount between 2 and 30% from the used cellulose raw material to the system in the extruder and mixing the cellulose fibers and the second chemical(s) in the mixing part of the extruder, wherein the mixing step is performed with a dry matter content of the cellulose material of at least 40%, heating the mixture to a temperature of at least 60° C., to produce a carboxymethylated cellulose having a degree of substitution between 0.02 and 0.4 carboxymethyl group per anhydroglucose unit, and refining the cellulose fibers in order to form the nanofibrillar cellulose material.