Fluorine-contg wood preserving composn - contg a metal fluoride

摘要

The protective compsn. contng. fluorine and which is hardening and water-sol. contains metal fluorides MexFy where Me = Al, Zn, Mg or mixtures of these. The metal fluoride is prepd. by the reaction of a sol. Al, Zn or Mg salt with an alkali fluoride in the presence of an alkali or acid solubiliser e.g. NaOH, alkali silicates, NaHSO4 or free acids. An example is: Al(NO3)3, 9H2O 1 mol., NaF 9 mols, NaOH 6.5 mols. The mixtures have a pH 13 and when wood is steeped in the soln. its acid components of pH is approx. 4 react to produce a cryolite compd. Na3(AlF6).