Influence of dipping time on uptake of preservative solution, adsorption, penetration and fixation of copper-ethanolamine based wood preservatives

Abstract

Copper-ethanolamine based wood preservatives are the most important products for protection of wood in use class III and IV applications. These preservatives can be applied using different procedures. One of them is dipping, a method which is predominantly used in less industrialised countries. The most important parameter, that influences the quality of this treatment, is dipping time. Influence of various dipping times on copper retention, adsorption, penetration, colour of the specimens and copper fixation was examined. In this paper copper-ethanolamine solutions of two different concentrations were utilised (cCu=0.05% or 0.25%). The results showed that longer dipping treatments resulted in higher uptakes of preservative solution, better penetrations and lower leaching of copper-ethanolamine based wood preservatives from Norway spruce wood. After one week of dipping, samples retained on average 275 kg/m3 of preservative solution, copper active ingredients penetrated on average 3 mm into the specimens, and only 2.3% of copper was emitted from wood impregnated with aqueous solution of the higher concentration, when subjected to ENV 1250 leaching procedure.