1519511 Wood preservative CANADIAN PATENTS & DEVELOPMENT Ltd 4 June 1975 [15 April 1975] 24135/75 Addition to 1458395 Heading A5E [Also in Division D1] A wood treating composition comprises an aqueous solution containing (a) a normally water-insoluble compound of zinc or zinc and copper with arsenic acid or arsenous acid in an amount of 0.1 - 4% by wt. (as metal) of the total aqueous solution, the molar ratio of zinc or zinc and copper (as oxides) to arsenic (as oxides) being 1.5 or more; (b) 0.15 - 10% by weight of the total aqueous solution of carbonate and/or bicarbonate ions in an amount of up to 150% of the zinc or zinc and copper; and (c) ammonia in an amount of 1-28% by weight of the total aqueous solution and sufficient to solubilise the normally water insoluble salt of zinc and copper, and the carbonate and/or bicarbonate.
