Development of Continuous Steam-Injection Press

设计了一套带有热板表面蒸汽喷射装置的连续压制系统，研究了制造厚度大于50 mm的无端刨花板的可行性。并对注汽压制的相关问题进行了基础研究。试验结果如下：1）试验安装的压力机具有800 mm（宽）× 1,200 mm（长）的蒸汽喷射压板，并可沿着颗粒流移动。结果表明，该间歇式热压机比传统的连续式热压机具有更简单的工艺流程和更好的注汽适应性。（2）在140 ℃下注汽10秒，热压80秒，可生产出厚度为100 mm，密度为0.6 g/cm ^3的刨花板。该压制周期比常规热压快20倍。3）往复压制接合部的水分凝结在某些情况下显著降低了内结合强度。采用有限元法对板坯内部的热扩散和温度分布进行了数值模拟，为预测热压周期提供了依据。脲醛树脂的最佳固化时间范围最大，而酚醛树脂和异氰酸酯树脂的最佳固化时间范围最大。

A continuous pressing system with a device of steam-injection from the hotplatem surfaces was designed and feasibility of manufacturing endless particleboard with thickness more than 50 mm was investigated. Fundamental research on the related problems to the steam-injection pressing was also made. The sesults are summarized as follows:1) The press installed trially had steam-injection platens of 800 mm (width) x 1,200 mm (length) and could move reciprocally along the stream of particle mat. It was verified that this type of intermittent press was more simple and adaptable to the steam-injection than conventional continuous presses.2) Particleboard of 100 mm thickness and 0.6 g/cm^3 density was producible by this press with 10 sec 140 c steam-injection followed by 80 sec hot-pressing. This press cycle is 20 times faster than that of conventional hot-pressing.3) The moisture condensation at the joint part of reciprocal pressing reduced the internal bond strength remarkably in some cases. However, the moisture condensation would be eliminated in some extent after some contimuation of production (warming-up).4) Numerical analysis of heat diffusion and temperature distribution in the mat by the finite element method was useful to predict the press cycle.5) It was shown that every resin had its own process of condensation and decomposition under high pressure steam-injection. urea resin had the narrowest time range optimum curing, while phenol and isocyanate resin had the broadest.