GB381583A - Improvements in and relating to the production of artificial moulded materials from cellulosic materials and binders - Google Patents

Abstract

Moulded artificial wood sheets are made from cellulosic material such as wood pulp and paper by forcing a concentrated solution of a binding agent such as glue, gelatine, casein or albumen through the sheet material and moulding either during or after or during and after drying. The impregnation may be effected by the use of a vacuum, hydrostatic pressure, pumps or centrifugal force. The superfluous solution which passes through the sheets may be collected and concentrated, if necessary, for re-use. Moisture may be removed from the cellulosic materials before impregnation by a preliminary treatment with a water repelling liquid such as benzine or trichlorethylene. Waterproof properties may be imparted to the product by adding to the binding agents hardening agents for glue such as tannin, alum, aluminium sulphate, acetate or formate, or substances such as caustic lime or baryta which form insoluble compounds with casein and albumen on drying, together with substances which delay the action of the hardening agents, for example acetic or formic acid for glue and ammonia in the case of albumen. After impregnation the binding agent is coagulated by cooling in the case of glue or by heating in the case of casein and albumen. The sheet is then either subjected to slight pressure to remove the bulk of the water and finally dried without further pressure, or dried at a low temperature and subsequently heated under pressure, or the two methods may be used in combination.