Not until the end of 1950 successful trials were made with
refiner pulps for papermaking. The pulp was made in atmospheric refiners in a system without
pre-treatment of the chips with steam and was called RMP (Refiner Mechanical Pulp). The development
of the technology for refiner pulps for printing paper production picked up speed
during the 1960’s when the principles for the present processes for production of TMP (Thermo-
Mechanical Pulp) started to take shape. In the TMP-process the chips are preheated and refined
in a steam pressurised system.