Method for manufacture of organically bound timber board, e.g. chipboard - involves over-compressing mat in hot plate press then separating plates to final desired thickness to induce secondary temperature rise.

Abstract
The method involves pressing a mat to be formed into board in a hot plate press for a first press phase period of 20-90 s. The mat is over-compressed to a thickness of 0.80-0.98 of the desired final thickness. The pressure is applied to the mat at least for long enough to allow 50-100 g of water to be sprayed on to the outer surfaces of the mat and for the water to reach the point where steam is starting to form. The energy of the water is such that when the plates are moved apart in a second press phase to a distance equal to the final thickness of the board, there is a secondary steam shock effect causing a spontaneous increase of temperature within the mat of at least 15 deg. . ADVANTAGE - The secondary steam shock effect reduces the pressing time to below that of conventional steam shock processes.