US 11,918,966 B2
Treating catalytically oxidized nanofibrillar cellulose hydrogel
Isko Kajanto, Espoo (FI)
Assigned to UPM-KYMMENE CORPORATION, Helsinki (FI)
Filed by UPM-KYMMENE CORPORATION, Helsinki (FI)
Filed on Apr. 16, 2021, as Appl. No. 17/233,192.
Application 17/233,192 is a continuation of application No. 15/538,074, granted, now 10,981,135, previously published as PCT/FI2015/050916, filed on Dec. 21, 2015.
Claims priority of application No. 20146138 (FI), filed on Dec. 22, 2014.
Prior Publication US 2021/0229057 A1, Jul. 29, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. B01J 13/00 (2006.01); A61K 8/04 (2006.01); A61K 8/73 (2006.01); A61L 2/00 (2006.01); A61L 2/26 (2006.01)
CPC B01J 13/0069 (2013.01) [A61K 8/042 (2013.01); A61K 8/731 (2013.01); A61L 2/0023 (2013.01); A61L 2/26 (2013.01); B01J 13/0065 (2013.01); A61L 2202/21 (2013.01)] 21 Claims
 
1. A heat treating method for preventing a greater than 30% change in viscosity of nanofibrillar cellulose hydrogel, the method comprising:
providing an oxidized nanofibrillar cellulose hydrogel having a dry-matter content of at least 0.6 weight-%, wherein the oxidation has been carried out through N-oxyl mediated catalytic oxidation of cellulose-based raw material, and has at most 50 μmol of aldehyde groups per gram of dry nanofibrillar cellulose;
subjecting the nanofibrillar cellulose hydrogel to a heat treatment, wherein the heat treatment comprises heating the nanofibrillar cellulose hydrogel at a predetermined temperature within the range of 100-150° C. in a closed environment, for a period of time in the range of 1 second to 180 minutes, wherein the predetermined temperature and the period of time are chosen such that the number of viable micro-organisms in the nanofibrillar cellulose hydrogel is reduced; and
cooling the nanofibrillar cellulose hydrogel to a temperature below 80° C. in the closed environment,
wherein the nanofibrillar cellulose hydrogel after the heat treatment has a viscosity of 2000-40000 mPas as measured at a 0.8% (w/w) concentration of the nanofibrillar cellulose in water with a Brookfield viscometer at a temperature of 20° C., with a vane spindle and a measuring speed of 10 rpm.