Resource-saving technologies in the production of glued laminated lumber with a glue line of increased strength

Abstract

One of the main problems of forestry is increased number of fellings and deforestation. Development of promising technologies in woodworking industry is one of the solutions to this problem. These technologies make it possible to reduce the production cost through the use of cheap and non-scarce materials and improve the quality of the resulting products to the level of premium products by improving the quality of the adhesive bond. The aim of the study is to obtain high-quality glued timber from non-grade oak wood (Quercus Robur L.) based on urea formaldehyde (resin, subsequently treated with ultrasound and constant magnetic field. The studies have shown that strength values of the adhesive bond based on the resin, subjected to shear testing along the wood grain, are significantly higher than that of the control specimens obtained using standard technology. Also, additional studies of internal stresses in the glue line and analysis of the microstructure were carried out. They enable obtain an explanation of the strengthening effect of adhesive joint.