GB495760A - Impregnating composition - Google Patents

Abstract

495,760. Proofing permeable materials ; treating wood. HODNEFIELD, O. March 15, 1937, No. 7587. [Class 140] Materials such as wood are rendered fireproof, waterproof, weatherproof and immune from the attack of insects by impregnation with a solution in ammonia of the reaction product of ammonium sulphate, ammonium phosphate, boric acid, colemanite, phenol, barium hydroxide, tin chloride and an alginate such as copper sodium alginate. Ammonium sulphate may be replaced by magnesium carbonate and ammonium phosphate by phosphoric acid. The composition is preferably made by mixing two aqueous solutions (a) containing ammonium sulphate, ammonium phosphate, boric acid, colemanite, and phenol, to which sodium fluoride, mercuric chloride and zinc chloride may be added, and (b) containing barium hydroxide, tin chloride, copper sodium alginate and ammonia to which aluminium ammonium sulphate, sodium bicarbonate, benzaldehyde, oil stains, pigments, dyes, and gum acacia or casein glue may be added. The solutions are mixed at a temperature of about 100‹ F., and under a pressure of about 150 lb. per square inch. In place of ammonia, solvents such as alcohol or an acetic-ether acetone mixture may be used. Wood is first steamed at low pressure, placed under vacuum and allowed to absorb the solution at 75 to 125‹ F. Pressure up to 150 pounds per square inch is then applied, surplus solution is withdrawn and the wood dried under slight vacuum and raised temperature. The treated wood may be painted or varnished.