Curved shape products are more preferable over products with sharp transitions due to less threatening notion (Bar and Neta, 2006). Also in the case of wood, the interest of curved objects is relatively high. Interior elements, furniture as well different outdoor structures frequently have integrated curvature in their shapes. For some of these purposes, glued wood materials made of thin lamellas are excellent allowing in relatively simple process create curved shape objects without any pre-treatment (steam treatment etc.) (Rowell, 1999). Different wood adhesives can be used for gluing, however for outdoor use the most important and easy to work on are one-component polyurethane (1C-PUR) and polyvinyl acetate (PVAc) D4, which both corresponds to the highest durability class D4 according to EN 204:2016. For curved outdoor products the adhesive should withstand not only the internal stresses caused by curved shape, but also moisture fluctuations including impregnation, which is important for ensuring suitable fungal resistance (Pitzner, Rambol and Lind, 2004). The objective was to investigate which of the one-component adhesives is the most appropriate for ensuring the highest quality of curved and impregnated glued-wood products intended for outdoor use.
Keywords: glued wood, polyurethane, polyvinyl acetate
Authors
Edgars Kuka
Latvian State Institute of Wood Chemistry, Riga Technical University, Dzerbenes iela 27, Riga, Latvia
Dace Cirule
Latvian State Institute of Wood Chemistry, Dzerbenes iela 27, Riga LV-1006, Latvia
Bruno Andersons
Latvian State Institute of Wood Chemistry, Latvia
Ingeborga Andersone
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