METHOD FOR PRESERVING WOOD AGAINST UNDESIRABLE REACTIONS CAUSED BY MICROORGANISMS

The present invention is related to a method for preserving wood against undesirable reactions caused by microorganisms. The invention also concerns wood preserved against molds, blue-stain fungi and rot fungi. According to the method, the wood being preserved is treated with a substance capable of inhibiting the growth of microorganisms, whereby said substance is penetrated into the wood at least essentially deeper than superficially. According to the invention, such a substance used in the method is a complexing agent, e.g., EDTA, which is capable of binding transition metals contained in the wood, whereby the complexing agent is first impregnated into the wood in a water-based solution, and subsequent to the impregnation step, the complexing agent impregnated into the wood is precipitated from the aqueous phase. The complexing agent can be precipitated by, e.g. lowering the pH of the wood, or alternatively, altering the temperature of the wood after the impregnation step. According to the invention, the complexing agent precipitated into the wood forms a reserve depot, whereby the substance re-dissolving from the depot is capable of binding transition metals entering the wood via rainwater or contamination.