Patent ID: 8906198

Claim:
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, wherein the pre-treating of the high consistency feed pulp is restricted to a single pass of the high consistency feed pulp 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 medium consistency pulp having a solids consistency of 6 percent to 15 percent; e) feeding the medium consistency pulp into a medium consistency refiner; f) using the medium consistency refiner to reduce the fiber length, fibrillate, and separate the fibers into strands and fibrillar elements; g) removing the medium consistency pulp from the refiner; h) repeating steps e) through g) at least four times to produce the MFC material, wherein each succession of steps e) through g) uses the removed medium consistency pulp produced by the prior succession of steps e) through g).