Production of hardboard in a closed water system

A process of manufacturing hardboard including the steps of:

• preparing a pulp stock comprising a suspension of lignocellulose fibres in water, said water also containing therein dissolved solubles which consist essentially of wood sugars released primarily during the pulp stock preparation, mechanically dewatering said pulp to form a wet mat, drying the wet mat by thermal evaporation, and subsequently pressing the dry mat between the forming surfaces of a heated press to form a hardboard, the improvement comprising:
• retaining the solubles released during said pulp stock preparation in the water in which said fibres are suspended collecting said solubles-containing water which is separated from said pulp during said mechanical dewatering thereof and feeding said solubles-containing water back to join the water which is used in the process, including that used to suspend the pulp, thereby to provide a closed water process with said water thereby being enriched principally by the dissolved wood sugars therein such that said wood sugars are present in the pulp stock in an amount of from about 2.5 to about 10% by weight, a substantial portion of the dissolved wood sugars in said wet mat being deposited on the surfaces of said mat during said drying of the mat by thermal evaporation, retaining said sugars on the surface of the dry mat, and effecting said pressing of the dry mat to form said board while maintaining the forming surfaces of the press at a temperature sufficient as to cause flowing and caramelization of the sugars retained on the major surfaces of the board immediately adjacent to or in contact with the press forming surfaces to thus provide a skin or crust of said sugars at said major surfaces of the board.