Process for the production of nano-fibrillar cellulose gels

Abstract

The present invention relates to a process for the production of naso-fibrillar cellulose gels by providing cellulose fibres and at least one filler and/or pigment; combining the cellulose fibres and the at least one filler and/or pigment; and fibrillating the cellulose fibres in the presence of the at least one filler and/or pigment until a gel is formed, as well as the nano-fibrillar cellulose gel obtained by this process and uses thereof.

1 - 17 . (canceled) 
     
     
         18 . A process for the production of a nano-fibrillar cellulose gel, characterized by the steps of:
 (a) providing cellulose fibres, wherein all or part of the cellulose fibres may be obtained from a recycled pulp;   (b) providing at least one filler and/or pigment;   (c) combining the cellulose fibres and the at least one filler and/or pigment of step (b); and   (d) fibrillating the cellulose fibres in an aqueous environment in the presence of the at least one filler and/or pigment in a homogenizer or an ultra-fine friction grinder until a nano-fibrillar cellulose gel is formed,   wherein the formation of the gel is verified by monitoring the viscosity of the cellulose fibres in the aqueous environment in the presence of the at least one filler and/or pigment in step (d) in dependence of the shearing rate, wherein the viscosity decrease upon step-wise increase of the shearing rate is stronger than the corresponding viscosity increase upon subsequent step-wise reduction of the shearing rate over at least part of the shear rate range as shearing approaches zero; and   wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:33 to 10:1.   
     
     
         19 . The process according to  claim 18 , wherein the cellulose fibres in step (a) are provided in the form of a suspension. 
     
     
         20 . The process according to  claim 19 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 0.2 to 35 wt-%. 
     
     
         21 . The process according to  claim 19 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 0.25 to 10 wt-%. 
     
     
         22 . The process according to  claim 19 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 0.5 to 5 wt-%. 
     
     
         23 . The process according to  claim 19 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 1 to 4 wt-%. 
     
     
         24 . The process according to  claim 19 , wherein the cellulose fibres in step (a) are provided in the form of a suspension at a solids content of from 1.3 to 3 wt-%. 
     
     
         25 . The process according to  claim 18 , wherein the filler in step (b) is in the form of particles having a medium particle size of from 0.01 to 15 μm. 
     
     
         26 . The process according to  claim 18 , wherein the filler in step (b) is in the form of particles having a medium particle size of from 0.1 to 10 μm. 
     
     
         27 . The process according to  claim 18 , wherein the filler in step (b) is in the form of particles having a medium particle size of from 0.3 to 5 μm. 
     
     
         28 . The process according to  claim 18 , wherein the filler in step (b) is in the form of particles having a medium particle size of from 0.5 to 4 μm. 
     
     
         29 . The process according to  claim 18 , wherein the filler in step (b) comprises a dispersing agent. 
     
     
         30 . The process according to  claim 29 , wherein the dispersing agent is selected from homopolymers or copolymers of polycarboxylic acids and/or their salts or esters, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, acryl amide or acrylic esters, or mixtures thereof alkali polyphosphates, phosphonic-, citric- and tartaric acids, salts or esters thereof or mixtures thereof. 
     
     
         31 . The process according to  claim 18 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:10 to 7:1. 
     
     
         32 . The process according to  claim 18 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:5 to 5:1. 
     
     
         33 . The process according to  claim 18 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:3 to 3:1. 
     
     
         34 . The process according to  claim 18 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:2 to 2:1. 
     
     
         35 . The process according to  claim 18 , wherein in step (d) the weight ratio of fibres to filler on a dry weight basis is from 1:1.5 to 1.5:1. 
     
     
         36 . A material composite, plastic, paint, rubber, concrete, ceramic, adhesive, food or wound-healing composite comprising the nano-fibrillar cellulose gel according to  claim 18 .