Vacuum technology was applied to the hot-pressing technology of plywood production with phenolic resin (PF). For plywood with the same number of layers, veneers were hot-pressed with conventional and vacuum hot-pressing processes respectively at the same hot-pressing time. Varying layers (3, 9 and 15-layers) and spread quantities (220 g m⁻², 260 g m⁻², 300 g m⁻²) were applied. Heat transfer performance of the assembly, polymerization extent of PF, and bonding quality of plywood were examined by thermocouple and humidity sensors, Fourier transform infrared spectroscopy (FTIR), fluorescence microscope and bonding strength measurement. The results indicated that, compared to conventional hot pressing, the temperature of the central layer of the assembly vacuum hot-pressed was significantly increased by about 20–30 °C and the adhesive cured more quickly. The hot-pressing method had a significant influence on the bonding strength of plywood, with an enhancement of the bonding strength to wood failure ratio of 48.37% and 33.55%, respectively. The adhesive between adjacent laminates formed a continuously dense layer with more connection points, leading to excellent mechanical meshing and high bonding quality. In addition, vacuum hot pressing can eliminate the influence of adhesive position on bonding strength and make the mechanical properties of plywood tend to be uniform in thickness direction. Under the experimental conditions, the variable energy cost of 15-ply plywood with 1 m³ produced by vacuum hot pressing was 3.83% less than that of conventional hot pressing, and the plywood could still maintain good bonding strength at low spread quantity.

中文翻译：

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真空热压对胶合板粘结质量和传热性能的影响

真空技术被应用于酚醛树脂（PF）胶合板生产的热压技术。对于具有相同层数的胶合板，分别在相同的热压时间分别用常规热压工艺和真空热压工艺对单板进行热压。不同的层（3,9和15层）和扩散量（220克间^-2，260克米^-2，将300g米^-2）被应用。通过热电偶和湿度传感器，傅立叶变换红外光谱（FTIR），荧光显微镜和粘合强度测量，检查组件的传热性能，PF的聚合程度和胶合板的粘合质量。结果表明，与传统的热压相比，真空热压的组件中心层的温度显着提高了20–30°C，并且粘合剂的固化速度更快。热压法对胶合板的粘结强度有显着影响，粘结强度与木材的破坏率分别提高了48.37％和33.55％。相邻层压板之间的粘合剂形成了一个具有更多连接点的连续致密层，从而导致出色的机械啮合和高粘合质量。另外，真空热压可以消除粘合剂位置对粘合强度的影响，并使胶合板的机械性能在厚度方向上趋于均匀。在实验条件下，15层胶合板与1 m的可变能源成本真空热压生产的胶合板³比常规热压生产的胶合板少3.83％，胶合板在低铺展量下仍能保持良好的粘结强度。