Pro Ligno (Jun 2013)
Adhesives Based on Furan Resin for Structural Laminated Timber
Abstract
In wood laminated products manufacturing thephenol-based adhesives are especially used. Recentlyother adhesives such as polyurethanes were promotedon the market for structural applications withremarkable properties. Structural adhesives have tofulfil the requirements according to their uses, underwet or dry conditions as adhesive type I and type IIrespectively. Criteria for evaluating structuraladhesives, includes delamination resistance, shearstrength of bond and percent of wood failure. Thisstudy has the objective to evaluate the bondingperformance of furan based resin and its suitability forstructural purposes. There are some investigationsabout the possibility of incorporating the furan resin intowood adhesive formulations but their industrialexploitation is still modest. Three experimentaladhesive compositions based on furan and ureaformaldehyderesins, were used to cold-glue beechand spruce lamellas to form a structural timber likeglued laminated timber. Adhesive formulations includedmixed furan resin with furfuryl alcohol (FC2) and twomodified furan resins with urea-formaldehyde resin(UR/FC2 and UR/FC3 at 50% UR). Bond shearstrength by longitudinal tensile and resistance todelamination were performed according to SR EN302:2004. The best performance was obtained withadhesive FC2 which showed shear strength above thevalues indicated for structural adhesives in EN301:2004. FC2 adhesive performed significantly betterin delamination tests too, both in dry and wetconditions, compared to the other two adhesives,showing promise for its use in load-bearing timberstructures.
