Hinoki cypress (Chamaecyparis obtusa) wood meal was liquefied at 150℃ using poly(oxyethylene) glycol as a liquefaction solvent in the presence of a sulfuric acid catalyst. Liquefied wood (LW) were characterized by residue content, hydroxyl number, moisture content, viscosity, molecular weight, molecular weight distribution, and FT-IR. About 85% of wood meal was converted to soluble components at the reaction time of 30min. Hydroxyl number and weight average molecular weight of LW was decreased with increasing liquefaction reaction. Wood boards were prepared from recycle chips with polyurethane resin adhesives based on LW, polymeric MDI and 1,4-butane diol. The flexural strength of wood boards was decreased with liquefaction reaction time of LW, however the strength was over that of JIS A5908.

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Polyurethanes having terminal triethoxysilyl group (silylated polyurethanes) were synthesized from isocyanate-terminated polyurethanes and a secondary aminosilane (silane endcapper). Dibutyltin dimethoxide (DBTDM) and boron trifluoride-monoethylamine complex (BF3-MEA) as curing catalysts were blended to the silylated polyurethanes with or without 3-aminopropyltnethoxysilane to afford curable compositions. The cured products of the curable compositions were exposed at 80℃ and 105℃ for different periods (1, 3, and 7 days) in order to compare the physical properties with the unexposed cured compositions in terms of tensile strength at break, elongation at break and durometer A hardness. It was found that the curable compositions using BF3-MEA were more stable than those using DBTDM even after the thermal treatment at 80 and 150℃ for 7 days, irrespective of the existence or absence of 3-aminopropyltriethoxysilane. The behavior was due to the different tendency of the hydrolytic cleavage of the urethane linkages the silylated polyurthanesas confirmed by IR measurement. As has been reported, the very high catalytic effect of BF3-MEA, and almost the same adhering properties of using BF3-MEA as those of DBTDM. BF3-MEA is one of the catalystssuitable for silylated polyurethanes, and widely applicable to adhesives, sealants, and coatings.

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The impact strength of an acrylic adhesive under high temperature was tested when impact tensile load was applied to tubular butt joints. The material of the adherend was aluminium alloy A5052-H34 and acrylic adhesive Hardloc M-372-20 was used. In the impact tensile test under high temperature, the thickness was fixed at 0.1mm. Main results are as follows: At the room temperature, the impact strength of the adhesive was higher than the staticone. The impact strength decreased with increasing the temperature, where in the adhesive layer maintained its shape for along time within 150℃ and for a short time with in 250 oC, respectively.

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