Process for production of micro fibrillated cellulose

Abstract

A method for producing micro fibrillated cellulosic material from pulp in which a pulp feed material is pre-treated by passing through a high consistency refiner a single time, followed by dilution and multiple passes through low consistency refiners.

What is claimed is: 
     
         1 . A process for producing micro fibrillated cellulose (MFC) material comprising:
 a) using a feed pulp material from cellulosic material processed to a high consistency feed pulp having a solids consistency of greater than 15 percent;   b) pre-treating the high consistency feed pulp in a high consistency refiner for a single pass through the high consistency refiner;   c) removing the high consistency feed pulp from the high consistency refiner;   d) diluting the high consistency feed pulp to form a low consistency pulp having a solids consistency of less than 6 percent;   e) feeding the low consistency pulp into a low consistency refiner;   f) using the low consistency refiner to reduce the fiber length, fibrillate, and separate the fibers into strands and fibrillar elements;   g) removing the low consistency pulp from the refiner; and   h) repeating steps e) through g) less than ten times to produce the MFC material, wherein each succession of steps e) through g) uses the removed low consistency pulp produced by the prior succession of steps e) through g).   
     
     
         2 . The process of  claim 1 , wherein the feed pulp material is wood pulp. 
     
     
         3 . The process of  claim 1 , wherein the produced MFC material has an average fiber length of 0.2 mm or less and 20 mg/l or higher water retention. 
     
     
         4 . The process of  claim 1 , wherein the pre-treating the high consistency feed pulp in a high consistency refiner step has a specific energy consumption of 600 KWh/ton or less. 
     
     
         5 . The process of  claim 1 , wherein the produced MFC material has an average fiber length of the MFC of 50 microns. 
     
     
         6 . The process of  claim 1 , wherein the produced MFC material is sent to a collection reservoir. 
     
     
         7 . The process of  claim 1  further comprising adding enzymes to the feed pulp material prior to step e) to form a pulp slurry, wherein the feed pulp material is agitated once the enzymes have been added. 
     
     
         8 . The process of  claim 7 , wherein the pulp slurry has a temperature of between about 30° C. and about 60° C. 
     
     
         9 . The process of  claim 7 , wherein the process has a duration between about 5 minutes to about 100 minutes. 
     
     
         10 . The process of  claim 7 , wherein contact of enzymes and pulp slurry is in a tank. 
     
     
         11 . The process of  claim 10 , wherein the tank is where dilution of the pulp slurry occurs. 
     
     
         12 . The process of  claim 1  further comprising adding enzymes to the feed pulp material prior to step e) to form a pulp slurry, wherein the feed pulp material is not agitated once the enzymes have been added. 
     
     
         13 . The process of  claim 12 , wherein the pulp slurry has a temperature of between about 30° C. and about 60° C. 
     
     
         14 . The process of  claim 12 , wherein the process has a duration between about 5 minutes to about 100 minutes. 
     
     
         15 . The process of  claim 12 , wherein contact of enzymes and pulp slurry is in a tank. 
     
     
         16 . The process of  claim 15 , wherein the tank is where dilution of the pulp slurry occurs.