Adhesive bonding of heat-treated wood

Abstract

S termično modifikacijo lesu zmanjšamo ravnovesno vlažnost, izboljšamo dimenzijsko stabilnost, povečamo trajnost ter odpornost proti glivam in insektom. Termično modificiran les ima drugačne lastnosti kot naraven les, zato je lepljenje takega lesa običajno zahtevnejše. Študije so pokazale, da termično modificiran les lahko kakovostno lepimo z večino industrijskih lepil za les, vendar je pogosto potrebno prilagoditi pogoje lepljenja in/ali modificirati lastnosti lepila. Trdnost lepilnih spojev termično modificiranega lesa je v splošnem odvisna od vrste lesa in stopnje modifikacije ter vrste lepila. Težavno je predvsem lepljenje z lepili na vodni osnovi, saj je modificiran les bolj hidrofoben.Thermal modification of wood reduces its equilibrium moisture content, improves dimensional stability, and increases durability and decay resistance.Bonding of heat-treated wood is difficult, because of its modified properties. Several studies had shown that heat treated wood can be sufficiently bonded with most of industrial wood adhesives, but usually some modifications of bonding process and/or adhesive need to be made. Adhesive bond strength of heat-treated wood depends on wood species, degree of modification and type of adhesive. Especially bonding with waterborne adhesives presents difficulties, because heat-treated wood is more hydrophobic