Hydroxymethylated resorcinol (HMR) priming agent for improved bondability of wax-treated wood

Abstract

The effects of hydroxymethylated resorcinol (HMR) on the tensile shear strength of wood joints treated with montan ester wax were studied with polyvinyl acetate (PVAc) and melamine formaldehyde (MF) adhesives. Untreated specimens which were bonded with MF and PVAc had similar bond strength properties under dry conditions, but MF bonded specimens' tensile shear strength values were higher than that of PVAc glued specimens under wet conditions. With both adhesives tested, dry tensile shear strengths of wax-treated specimens were in a comparable range to those of untreated wood, while under wet conditions the strength values of wax-treated specimens were significantly lower than those of the controls. HMR priming increased the shear strength of PVAc bonded specimens under wet conditions and of MF-bonded specimens under dry and wet conditions. The effect on MF-bonded specimens, however, was much more pronounced under wet conditions.