Patent ID: 9663588
Date: 2017-05-30
CPC Classifications: C08B,D21C,D21H,Y10T

Claim:
1. A method for concentrating nanofibrillar cellulose, comprising: subjecting only nanofibrillar cellulose, which is a wood-based material, in a liquid medium at a concentration of not higher than 6% and at a temperature of 30-70° C., to pressure filtration such that liquid is removed in two opposite directions from the nanofibrillar cellulose by applying pressure of at least 5 bar to the nanofibrillar cellulose, and continuing the pressure filtration to an end point where over 50% of the liquid initially present is removed from the nanofibrillar cellulose, to the final dry substance of 10-30% of nanofibrillar cellulose, whereby the nanofibrillar cellulose in this final dry substance is redispersable in water and will give, when redispersed in water at a dispergation concentration in the range of 0.5-1.0 wt-%, a viscosity profile that is equal to the viscosity profile it had originally at the same dispergation concentration.