– Average values of strength of the glue line from tested adhesives, according to applied conditioning and side orientation.
The study compares the strength of the glue line of edge glued panels of Pinus taeda made with different industrial adhesives. Three types of adhesives (poly(vinyl) acetate (PVAc), emulsion polymer isocyanate (EPI) and polyurethane (PU)) glued in two side gluing orientation (radial and tangential) and analyzed after the conditioning tests (dry and...
This study applied response surface methodology for modeling and optimizing heat-treated wood dowel joints, the most used joint in furniture construction. The factors examined were dowel length, dowel diameter, and adhesive consumption. The bending moment capacity of the joints loaded in compression or tension were the responses. The load was appli...
The potential of Attalea maripa and Attalea speciosa was evaluated for the production of edge-glued panels. The chemical and physical properties and the quality of the bonding of the species and mixed treatment between them, under different conditions, were evaluated. The length bonding was performed with polyvinyl acetate (PVA) adhesive and the side with PVA and emulsion polymer isocyanate (EPI) in two spreading rates. The species A. maripa has a lower content of extractives in cold and hot water, total extractives, ash and pH, and higher density compared to A. speciosa. The tangential, radial and volumetric shrinkage and shrinkage anisotropy of the species were statistically equal. On the length bonding, only in the tensile test after drying pre-treatment were the requirements of the technical standards not met. As regards side bonding, the treatments of A. maripa and mixed joints with EPI reached the standard for the pre-treatment in cold water.
Edge-glued panels are composed by the lateral and top gluing with adhesives of solid battens. These panels use small pieces of wood, offering an optimal usage of forest resources and the development of higher value-added products. The adhesive generally used to produce the panels are the synthetic ones (PVA or EPI). The polyurethane derived from castor oil may arise an alternative to replace the adhesives derived from non-natural origin, because it has no solvent in its composition, is a biodegradable material and it comes from a renewable resource. The bonding quality of this panel was performed according to BS EN 13353, which specify the minimum resistance values for panels under different humidity and temperature conditions applied to the international market. In this context, the aim of this paper was to evaluate the lateral gluing quality of Pinus taeda panels using the polyurethane derived from castor oil, as well as assess the pressing time effect on the bonding quality. The adhesive was applied into the battens surface in weight of 180 g/m2. The panels were put into a cold press machine for 1, 2, 4, 8 and 24 h, totalizing five conditions and eight together/replications. The bonding quality of this panel was performed according to BS EN 13353 and BS EN 13354, under different humidity and temperature conditions. The results were submitted to statistical analysis by outlier tests, normality test, homogeneity variance, analysis of variance and mean comparison, all with 95 % reliability. The polyurethane showed acceptable values to EN-13353 for 4 h in the press machine. The test for critical humidity and temperature conditions showed a reduction in the adhesive bond strength, but still acceptable to EN-13353. Under these circumstances, it is concluded that the polyurethane derived from castor oil may be an alternative to produce lateral glued panels for dry conditions and internal and external applications for humid conditions.