| 摘要 |
The invention relates to a process for the production of boards of wood-based material from a mixture of lignocellulose- and/or cellulose-containing particles mixed with a binder, the mat or pressed stock being preheated by means of high-frequency (HF) or microwave (MW) energy and, after transfer into a single or multi-platen press or a continuously operating press, being pressed and cured by the application of pressure and heat. To increase the preheating temperature of the pressed stock and to reduce the pressing factor, the following process steps are provided: (a) the preheating in the core of the mat of pressed stock to >=85° Celsius takes place after or during the precompaction by traveling wave microwave energy and its reflection in an interaction between emitted and reflected energy into the center of the mat of pressed stock, a focusing of the radiation energy into the center cross section being performed at a large energy-introduction and energy-absorption angle beta, for an increased heat gradient, and (b) the preheated mat of pressed stock enters the pressing region of the press with a moisture content which is 15% to 30% less than the conventionally-controlled moisture content.
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