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During hot pressing, we measured continuously the transition of temperature at various positions in the particle board as shown in Fig. 1, made of hammier-mill type particles (splinters) from waste lauan veneer and soya bean flour as shown in Table 1, with the alumel-cromel thermocouples (diameter 0.3 mm). The hot press cycles were varied and then the physical and the mechanical properties of the board were tested. The results of this study are as follows; 1) The temperature of the outer layer of board raise rapidly at first then slowly approach to the hot platen temperature, but the temperature of the inner layer raise gradually and reach to the maximum value, the lower to the minimum value, and raise again up to the hot platen temperature gradually. Therefore the difference of the temperature between the outer layer and the inner layer of board decrease after passing the minimum value of inner layer temperature of the board. (Fig. 3) 2) The longer the hot press cycle, the higher the value of modulus of elasticity, modulus of rupture and Brinell hardness, but the lower the impact bending absorbed energy of the particles, and the feeding quantity of heat. There is not significant relation between the specific bending strength and the hot press cycle. (Fig's. 4 and 5) 3) The water absorptivity of board is remarkably high at 27 min. hot press cycle, but its value is low at longer than 32 min. cycle and it varys a little as shown in Fig. 6. (This is owing the fact that the quantity of heat feeded is not enough at 27 min. hot press cycle to cure the adhesives in the board.) There is not singificant relationship between the hygroscopicity of board and hot press cycle as shown in Fig. 7. 4) In conclusion; the longer the hot press cycle, the more curing the adhesives, therefore the strength properties except the impact bending absorbed energy, and the water absorptivity are improved, but the more fragile the wood particle, therefore the impact bending absorbed energy decrease contrary.

The wettability of wood-plastic combination (WPC) is worse than that of untreated wood. This wettability depends strongly on the polymer content. For that, it may be difficult that WPC is glued with conventional wood gluing technique. In the present paper, the effect of open assembly time and polymer content on the gluability is investigated using several conventional adhesives. The wood specimen used in this experiment was prepared from clear, defect-free sliced veneer of Kaba (Birch, Betula Maximowicziana REGEL : 1.5mm thickness, 15% moisture content). The specimens were extracted with ethanol-benzene solution to extract soluble materials. WPC was produced with the wood-methyl methacrylatebenzene-benzoyl peroxide system by means of the heat-catalyst polymerization method. Before gluing, the gluing surface was sanded. The three-ply plywoods were made from treated wood or control (extracted and sanded-wood) with urea-formaldehyde resin adhesive (UF), resorcinol-formaldehyde resin adhesive (RF), epoxy resin adhesive (Epoxy) and polyvinyl acetate emulsion (PVAc) by the gluing condition shown in Table 1. After these plywood had been stored in a conditioning chamber held at 20℃ and 60% R. H. for 1 week, the tensile shear specimens were tested in a universal testing machine according to the Japan Agriculture Standard Specification. An analysis of variance for the polymer content and open assembly time was made separately on each adhesive. The analysis of variance is shown in Table 2. The results obtained were as follows ; 1) For all adhesives used in this experiment, the 1% level of significance was indicated on the polymer content (Table 2). For UF.RF and Epoxy,the tensile shear strength of the glue-joint decreased along with increased polymer content : UF gave especially inferior results (Figs. 1, 2 and 3). For PVAc, the tensile shear strength of the gluejoint generally increaed with the increasing of the polymer content (Figs. 4 and 5). 2) For RF and PVAC (cold-press), the tensile shear strength of the glue-joint decreased with the increasing of the open assembly time at the 1% level of significance (Table 2, Figs. 2 and 4). 3) For Epoxy and PVAc, the interraction of the polymer content and open assembly time indicated significance at the 1% level (Table 2, Figs. 3, 4 and 5). 4) The wood failure for control was almost 100%. On the other hand, that for WPC was very low (zero or nearly so) but 30 to 50% wood failure was observed for RF and PAVc (hot-press).