热压条件对薄片刨花板厚度方向上膨胀分布的影响

传统的降低板材厚度膨胀的方法主要是通过提高施胶量和添加石蜡，或通过热、蒸汽、化学处理等，但往往会增加成本及影响材料的力学性能。板材厚度膨胀的最主要根源是木材的结构和特性以及热压时水分、温度、压力和时间对板材的综合作用。笔研究了在不同的热压条件下，板坯内不同层的薄片刨花的膨胀以及薄片刨花板厚度方向上的膨胀分布。结果表明，在较低的热压温度下，刨花的压缩率和膨胀率呈明显的相关性，而在较高的热压温度下，尽管表层刨花的压缩率较高，但其厚度膨胀率仍小于芯层刨花。为降低木质复合材料的厚度膨胀，建议采用较高的热压温度。

Effect of Hot-pressing Condition on Swelling Profile of Flakeboard

Traditional approaches to reducing thickness swelling rely on high resin and wax addition which increases manufacturing costs,or heat/steam/chemical treatment which often reduces product strength properties simultaneously.Being inquired into the root of thickness swelling,the structure and characteristics of wood and the interactive relationships of temperature,moisture,pressure and time during hot-pressing may play an important role.In this paper,the swelling behaviors of flakes in the different layer of mat under the interactions of heat,moisture and pressure and the swelling profile of commercial flakeboard were investigated.The results indicated that the pressing temperature affected thickness swelling of flakes significantly.A strong correlation was exhibited between the thickness swelling and compression ratio under low pressing temperature.However,under high temperatures,the thickness swelling of flakes from the surface layer was lower than that of the core layer though imposed high compression.To reduce thickness swelling of OSB or flakeboard,the higher pressing temperature is recommended.