| 摘要 |
<p>This invention relates to a novel composite board made from a mixture of particles of a cellulose material and binder and a method of making same whereby the composite board so produced displays improved dimensional stability (resistance to thickness swellling) when the board is subjected to high humidity or moisture conditions. As a result, the novel method and composite board produced thereby can be employed as a construction material in locations hitherto regarded as unacceptable or questionable due to the undesired thickness swelling characteristic of conventional composite panels such as particlehoard or waferboard. The method and composite board displaying the attribute of improved dimensional stability involves subjecting a composite board that is conventionally formed by heat and pressure treatment to a secondary heat treatment for a predetermined period of time and at preselected temperature range. When compared to conventional composite board that has not been subjected to secondary heat treatment, the difference in thickness swelling is significant. The board surfaces and board edges are preferably subjected to the secondary heat treatment. Admixtures of regular resins and a slower curing binder such as spent sulphite liquor, hitherto regarded as unsuitable in the production of composite board, can now also be employed.</p> |
