針葉樹バークを原料としたブロック状成形物の製造と材質評価

抄録

A composite made from bark, named bark-block, was developed to promote utilization of the bark residue. Airdried bark of Japanese conifers (sugi and hinoki) was used as furnish. The bark-block with dimensions of 400mm by 400mm by 55mm was fabricated using urethane resin as a binder. Steam was injected during pressing through holes on the press platen. Target density of this composite was 0.4g/cm³. A small-scale production machine that can be installed in a local sawmill or a logging site was designed for this purpose. The effect of manufacturing parameters on the properties of the bark-block was investigated to obtain the optimum conditions. The experimental results showed that bending properties (MOR and MOE), compressive stiffness, and IB strength increased with increasing resin content. Mechanical properties were proved to be controlled by the amount of the resin applied. It was found that the preferable steam injecting time for resin curing was 3 minutes. Thickness swelling was from 5 to 10 percent after water immersion treatment, while the water absorption was more than 80 percent. The bark-block produced have started to be used as a paving material in a park or in an exposition.