Timber preservatives based on a zinc cpd. and an aliphatic carboxylic acid which do not contain a copper cpd. are new when they additionally contain a polyamine. New impregnation solns. for the preservation of timber are obtd. by dilution of timber preservatives as defined above with water. Pref. carboxylic acid is 2-ethylhexanoic acid. The pref. zinc cpd. is zinc hydroxide, and the pref. polyamine is 3,3'-diaminodi-propylamine. Compsn. pref. additionally contain a complex-forming carboxylic acid, an alkali or zinc salt of N-cyclohexyl-dioxydiazenium oxide, a quat. ammonium cpd. and/or lactic acid.
