Upm-kymmene Corporation

Markku Gummerus

Taisto Tienvieri

The object of the present invention is a method for making mechanical pulp, such as thermomechanical or chemi-thermomechanical stock. The mechanical pulp is used as a raw material for printing paper, and its freeness value is 30-70 ml CSF. The stock refined by the method is screened in several stages to form accept and reject stock portions. The wood raw material is refined at the first stage of refining at a superatmospheric pressure of over 400 kPa to form a stock that has a freeness value of 250-700 ml CSF.

Raw material for printing paper, a method for producing said raw material and a printing paper

The object of the present invention is a method for making mechanical pulp, such as thermomechanical or chemi-thermomechanical stock. The mechanical pulp is utilised as a raw material for printing paper, and its freeness value is 30&mdash;70 ml CSF. According to the method, the refined stock is screened in several stages into accept and reject stock portions. The stock is screened at a consistency of not less than 10%.

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Tampere, Finland

Markku Gummerus