研究了环境相对湿度和温度对3种不同取向聚丙烯（PP）薄膜的水蒸汽透过率的影响。试验结果表明：随着温湿度的增大，聚丙烯薄膜的水蒸汽透过率也增大；聚丙烯薄膜的水蒸汽透过系数受温度的影响要显著于相对湿度；在一定的温湿度条件下，双向拉伸聚丙烯（BOPP）、单向拉伸聚丙烯（OPP）和未拉伸聚丙烯（CPP）3种薄膜的透湿系数值依次增加，说明拉伸取向操作可提高PP薄膜的阻湿性能。

The influence relative humility and temperature on water vapor transmission rate of polypropylene films with different tropisms were studied. The result indicated that the water vapor transmission rate of polypropylene films increases with temperature and relative humility; temperature has greater influence on water vapor permeability of polypropylene films than humidity; under the same temperature and relative humility, water vapor permeability of BOPP, OPP, and CPP films increases successively. It was concluded that vapor permeability of PP films decreases by stretch orientation.