A method of mechanical pulping. Like refiner mechanical pulping, TMP sandwiches wood chips between the two rotating disks of a disk refiner, but under higher temperature and pressure. (In many cases, the wood chips are preheated.) The higher temperatures and pressures soften the lignin even more than can be accomplished using frictional heat, and fiber separation is easier. Additional passes through the system increases defiberization, and longer fibers and fewer fines are generated. Thermomechanical pulp is stronger than refiner mechanical pulp, and still retains the high-yield and cost-effectiveness of mechanical pulps. Newsprint made with TMP has been found to possess higher runnability on the press. (See Mechanical Pulping.)
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