Influence of wood swelling agents on penetration and copper leaching of copper-ethanolamine based wood preservatives
IRG/WP 11-30556
M Humar, N Thaler, B Lesar
Copper ethanolamine based preservatives are currently the most important solutions for impregnation of wood in ground contact in Europe. One of the issues related to those and similar water based solutions is insufficient penetration to refractory wood species like Norway spruce. In order to elucidate this issue, commercial copper ethanolamine based solution was supplemented with five different wood swelling agents (ammonia, ethylene glycol, DMSO, formic acid and triethanolamine) of three different concentrations (2.5%, 5% and 10%). Norway spruce wood specimens were impregnated with those solutions, and uptakes of preservative solutions and depth of penetration was determined. Furthermore, copper leaching according to the ENV 1250-2 procedure was determined as well. The results showed that triethanolamine and formic acid were found very effective and improved penetration of copper ethanolamine wood preservative to wood. On the other hand, addition of those two preservatives increased copper leaching from impregnated wood.