Upm-kymmene Corporation

Taisto Rintamaeki

Hannu Suksi

Jorma Mattila

Isko Kajanto

Markus Nuopponen

Juha Tamper

Taisto Tienvieri

Janne Laine

Kari Luukko

Jaakko Pere

Tapani Vuorinen

Sami Saarela

Lauri Paasonen

Mika Kosonen

Timo Pääkkönen

Anne Meriluoto

Tarja Sinkko

Tero Taipale

Tero Ojala

Teija Jokila

Maria Alajaaski

Timo Paakkonen

Maria ALAJÄÄSKI

The invention relates to a method for treating a nanofibrillar cellulose hydrogel, wherein the method comprises the steps of: providing a nanofibrillar cellulose hydrogel, wherein the nanofibrillar cellulose is oxidized nanofibrillar cellulose, 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; and subjecting the nanofibrillar cellulose hydrogel to a heat treatment.

Treating catalytically oxidized nanofibrillar cellulose hydrogel

A process for producing an oxidized nanofibrillar cellulose hydrogel is disclosed, wherein the process comprises oxidizing cellulose pulp fibers in the presence of hypochlorite as an oxidant and a heterocyclic nitroxyl radical as a catalyst; and disintegrating the oxidized cellulose pulp fibers to obtain a nanofibrillar cellulose hydrogel; wherein all steps of the process after oxidizing are performed under aseptic conditions. An oxidized nanofibrillar cellulose hydrogel and a system for producing the same are also disclosed.

Process for producing an oxidized nanofibrillar cellulose hydrogel

In a method for producing nanofibrillar cellulose, cellulose based fibre material, in which internal bonds in cellulose fibres have been weakened by 5 preliminary modification of cellulose, is subjected to disintegration treatment in form of pulp comprising fibres and liquid. The fibre material is supplied at a consistency higher than 10 wt-%, preferably at least 15 wt-%, to a disintegration treatment where fibrils are detached from the fibre material by joint effect of repeated impacts to the fibre material by fast moving 10 successive elements and the weakened internal bonds of the cellulose fibres. The nanofibrillar cellulose is withdrawn from the disintegration treatment at dry matter which is equal or higher than the consistency of the fibre material.

Method for producing nanofibrillar cellulose and nanofibrillar cellulose product

A method for controlling the catalytic oxidation of cellulose includes using a heterocyclic nitroxyl compound as catalyst; oxidizing cellulose in a reaction mixture comprising liquid medium, the catalyst and hypochlorite as main oxidant; analyzing one or more oxidative chlorine species dependent on the hypochlorite concentration of the reaction mixture on line in the reaction mixture or in a gas composition which is in contact with the reaction mixture; and controlling supply of hypochlorite to the reaction mixture on the basis of the analysis.

Method and apparatus for controlling the catalytic oxidation of cellulose

The invention relates to a method for treating a nanofibrillar cellulose hydrogel, wherein the method comprises the steps of: providing a nanofibrillar cellulose hydrogel, wherein the nanofibrillar cellulose is oxidized nanofibrillar cellulose, wherein the oxidation has been carried out through N-oxyl mediated catalytic oxidation of cellulose-based raw material, and has at most 50 &#x3bc;mol of aldehyde groups per gram of dry nanofibrillar cellulose; and subjecting the nanofibrillar cellulose hydrogel to a heat treatment.

A process for producing a nanofibrillar cellulose hydrogel comprises obtaining bleached cellulose pulp fibers and providing an aqueous suspension thereof; and subjecting the cellulose pulp fibers in the aqueous suspension to at least 2 cycles of high pressure mechanical disintegration to obtain a nanofibrillar cellulose hydrogel and thereby reducing the number of viable microorganisms present in the suspension by a factor of at least 10; wherein all steps of the process after obtaining the bleached cellulose pulp fibers are performed under conditions of ISO 8 of ISO 14644-1 cleanroom standards or stricter. A nanofibrillar cellulose hydrogel, a system for producing the same and the use of a disintegrating apparatus are also disclosed.

Process for producing a nanofibrillar cellulose hydrogel

In a method for producing nanofibrillar cellulose, cellulose based fibre material, in which internal bonds in cellulose fibres have been weakened by preliminary modification of cellulose, is subjected to disintegration treatment in form of pulp comprising fibres and liquid. The fibre material is supplied at a consistency higher than 10 wt-%, preferably at least 15 wt-%, to a disintegration treatment where fibrils are detached from the fibre material by joint effect of repeated impacts to the fibre material by fast moving successive elements and the weakened internal bonds of the cellulose fibres. The nanofibrillar cellulose is withdrawn from the disintegration treatment at dry matter which is equal or higher than the consistency of the fibre material. In the disintegration treatment, the fibre material is supplied through several counter-rotating rotors (R, R, R. . . ) outwards in the radial direction with respect to the rotation axis (RA) of the rotors in such a way that the material is repeatedly subjected to shear and impact forces by the effect of the blades () of the different counter-rotating rotors.

Cellulose is oxidized catalytically using a heterocyclic nitroxyl radical as catalyst, main oxidant acting as oxygen source, and an activator of the heterocyclic nitroxyl radical. The oxidation is performed in a reaction medium which is at medium consistency of cellulosic pulp, which is above 6%, more preferably equal to or higher than 8%, and most preferably in the range of 8-12%. The reaction medium is mixed in a reactor through circulation of the reaction medium back to the reactor.

Method for catalytic oxidation of cellulose and method for making a cellulose product

The present invention provides a method for producing fibrillated cellulose, the method comprising providing pulp, treating said pulp at a consistency of at least 10% with a cellulase, and fibrillating said pretreated pulp to obtain fibrillated cellulose. The present invention also provides a nanofibrillar cellulose product.

Method for producing fibrillated cellulose

The method for preparing nanofibrillar cellulose comprises

Method for preparing nanofibrillar cellulose

The invention relates to a method for treating a nanofibrillar cellulose hydrogel, wherein the method comprises the steps of: providing a nanofibrillar cellulose hydrogel; and subjecting the nanofibrillar cellulose hydrogel to a heat treatment, wherein the heat treatment is carried out by transferring the nanofibrillar cellulose hydrogel through at least one heat exchanger or through at least one insulated holding tube, during which heat treatment the nanofibrillar cellulose hydrogel is kept at a predetermined temperature within the range of 110-150&#xb0; C. for a period of time in the range of 15 seconds to 20 minutes, wherein the pre-determined temperature and period of time are chosen such that the number of viable micro-organisms in the nanofibrillar cellulose hydrogel is reduced by a factor of at least 10.

Heat treatment of a nanofibrillar cellulose hydrogel

The invention relates to a method for reducing the viscosity of a nanofibrillar cellulose hydrogel, wherein the method comprises mixing a nanofibrillar cellulose hydrogel with an aqueous growth medium for cell culture, wherein the aqueous growth medium contains one or more salts and optionally one or more sugars, using shearing forces so that a homogeneous dispersion is formed. The invention further relates to a dispersion comprising a nanofibrillar cellulose hydrogel and an aqueous growth medium for cell culture and to a use of an aqueous growth medium.

Method for reducing the viscosity of a nanofibrillar cellulose hydrogel

Method for making modified cellulose products comprises &#x2014;processing cellulose pulp to modified cellulose pulp at a manufacturing location to increase the susceptibility of fibers to disintegration, &#x2014;setting the modified cellulose pulp to a suitable dry matter content, and &#x2014;transporting the modified cellulose pulp at set dry matter content to a location of use, where the modified cellulose pulp is disintegrated to nanofibrillar cellulose.

Method for making modified cellulose products

One embodiment provides a method for monitoring the quality of nanofibrillar cellulose produced in a process comprising disintegrating fibers of cellulose pulp, the method comprising measuring in real-time optically the turbidity of a dispersion containing nanofibrillar cellulose obtained from a disintegrating process, and determining the quality of said produced nanofibrillar cellulose using a correlation between the measured turbidity and said quality of the produced nanofibrillar cellulose, wherein lowered turbidity indicates increased quality of the nanofibrillar cellulose. One embodiment provides a device for monitoring the quality of nanofibrillar cellulose produced in a process comprising disintegrating fibers of cellulose pulp, arranged to carry out said method.

Method and device for monitoring the quality of nanofibrillar cellulose

A method for making nanofibrillar cellulose includes mixing anionized or cationized cellulose fibers and cellulose pulp to a mixture including at least 1% and below 90 wt-% cellulose pulp based on dry weight, and subjecting the mixture to a refiner stage where the anionized or cationized cellulose fibers are at least partly reduced to nanofibrillar cellulose and the cellulose pulp acts as auxiliary pulp, and obtaining a mixture of nanofibrillar cellulose and cellulose pulp from the refining stage. The mixture can be used for making paper by adding it to base pulp.

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Espoo, Finland

Isko Kajanto