板坯表面喷水对干法纤维板热压传热的影响

该文在不同板材密度和厚度、不同板坯含水率及热压温度条件下，对干法纤维板板坯的表面增湿后进行热压，并测定板坯中心层在热压过程中的温度变化数据，比较、分析了各条件下不同表面喷水量时中心层温度的变化曲线.结果表明:①板坯表面增湿处理对板坯表面温度的上升速度影响较小，仅有短暂的温度停滞现象.②板坯表面增湿处理不适于要求固化温度在120℃以上的胶粘剂，板坯表面增湿处理有利于提高板坯中心层在达到水分沸点温度之前的升温速度.③板坯中心层的升温速度随板坯表面喷水量的增加而增加，但当表面喷水量达到某值（即最佳喷水量）后，其升温速度不再明显增加.此最佳表面喷水量随板材密度和厚度的增加及热压温度的提高而增大.④对相同的表面喷水量，板材密度或厚度越小、板坯含水率越低，就越能明显增加板坯中心层的升温速度，而热压温度对其影响不大.⑤板坯表面增湿处理，能使其中心层的升温速度提高约一倍. 

Influence of surface sprinkling on the heat-conduction of dry-process fiberboard under hot-pressing

The humidifying treatment in the mat surface was adopted during the hot-pressing process to make dry-process fiberboard under different conditions. The changes of temperature in the core layer and the surface of a mat were measured. Based on the analysis of the curves of changing temperatures, conclusions are as follows: 1) humidifying treatment in the mat surface of dry-process fiberboard has little effect on raising mat surface temperature. 2) humidifying treatment in the mat surface is not suitable for an adhesive whose curing temperature is above 120℃. It accelerates the speed of temperature increase before the temperature of the core layer reaches water vaporization point. 3) the speed of temperature increase of the core layer of the mat increases with the sprinkling amount of the mat surface, but the speed does not increase obviously when the sprinkling amount of the mat surface reaches an optimum level. The optimum sprinkling amount increases when the density or thickness of panels or hot-pressing temperature increases. 4) for the same sprinkling amount of the mat surface, the speed of temperature increase of the core of mat increases obviously when the density or thickness of a panel or sprinkling amount of the mat is low, while the temperature of hot-pressing has little effect on it. 5) humidifying treatment in the mat surface almost doubles the speed of core temperature increase of the mat.