GB470772A - Method of making artificial lumber - Google Patents

Abstract

Artificial lumber, wall boards, and the like are manufactured by mechanically disintegrating in the wet state natural raw uncooked woody material, without the use of high temperatures and pressures, to produce a wet mass of fibres, incorporating therewith a binder consisting of synthetic-resin-forming ingredients or of a partial condensate thereof in an aqueous medium, draining the mass to obtain a felted mat of fibres, partially drying the said mat and hot-pressing. Suitable woody materials are sawdust, chips, shavings, and trimmings from veneer plants. The binder may be prepared from phenol, m-cresol or crude carbolic or cresylic acid, with or without urea, and formaldehyde, polymers thereof, or hexamethylene-tetramine. After incorporation of the mass with the binder there may be added a mineral acid, e.g. hydrochloric or sulphuric acid, or a salt of acid reaction, e.g. aluminium sulphate, to precipitate the partial condensate; or waterproofing materials, e.g. waxes, pitches, wax tailings. Before draining, the mix may be passed through a Jordan. The partial drying may be carried out, e.g. by suction or pressing. In examples, binders are prepared from cresylic acid and formaldehyde with or without urea, in aqueous solution (which may also contain denatured ethanol, methanol, triethanolamine, oleic acid) in the presence of condensing agents such as caustic soda, caustic potash, ammonia, sodium arsenate, sodium sulphite, lime water, and barium, magnesium, manganese, sodium and zinc acetates; in example 5, saponified linseed oil is an ingredient. Specification 28155/10, [Class 2 (iii)], is referred to.