增重法与减重法在不同包装材料中的应用

目的探究基于称重法原理的增重法与减重法在不同包材领域内的应用范围。方法避免人工、环境等引入测试误差导致的对比偏差,采用透湿试验腔内自动称量的智能检测仪器,依据ASTM E96标准方法中的增重法与减重法,测试并比较在不同温湿度实验条件下塑料薄膜、纸铝塑复合膜、人造皮革、无纺布等7种不同材质与阻湿性样品的水蒸气透过率。结果纸铝塑复合膜、人造皮革及无纺布样品分别利用增重法和减重法所测得的水蒸气透过率结果有明显差别,而其余4种样品差值不明显;人造皮革样品的增重法实验结果高于减重法的结果,而纸铝塑复合膜及无纺布这2种样品的结果则相反。结论增重法与减重法在测试水蒸气透过率时并非在任何条件下均适用于所有包装材料,应根据样品的材质、结构、使用环境条件及实际用途等因素合理选用增重法或减重法进行检测。

Application of Desiccant Method and Water Method in Different Packaging Materials

The work aims to study the application of desiccant method and water method based on the principle of gravimetric method in the field of different packaging materials. The compared deviation caused by the test error induced by the manpower, environment and other factors was avoided. An intelligent detection instrument which comprised automatic weighing in the water vapor permeability test chamber was adopted. According to desiccant method and water method of ASTM E96, the water vapor transmission rate of seven kinds of different materials and moisture retardant samples at different experimental temperatures and humidity, including plastic film, paper-aluminum-plastic composite film, artificial leather and non-woven fabric were tested and compared. For samples of paper-aluminum-plastic composite film, artificial leather and non-woven fabric, there was significant deviation of results measured respectively in desiccant method and water method, but no obvious difference for other four samples. For artificial leather sample, the test result of desiccant method was obviously greater than that of water method, but the result was opposite for paper-aluminum-plastic composite film and non-woven fabric. The desiccant method and water method cannot be applied to all packaging materials in any condition for the testing of water vapor transmission rate. The desiccant method or water method should be selected reasonably based on some factors, such as the sample material, structure, operation conditions and actual application.