Patent ID: 6878236

Claim:
A method for producing thermomechanical and chemi-thermomechanical pulp effective for use as a raw material for printing paper, the method comprising: refining wood raw material in a first refining stage at a superatmosperic pressure of greater than 400 kPa, the first refining stage effective for forming a first refined stock with a freeness value of 250 to 700 ml CSF; screening the first refined stock into a first accept and first reject portion; refining and screening the first reject portion in at least one additional stage into accept and reject stock portions; and combining the first accept stock portion and accept stock portions to form a ready made stock, the time and temperature of the first refining step being effective for providing the ready made stock with 40 to 50% of fibers not passing through screens of 16 and 28 mesh and 35-40% of fibers passing through screens of 48 and 200 mesh and wherein the ready made stock has a freeness value of 30 to 70 ml CSF.