塑料 - 聚（氯乙烯） 相关含氯均聚物和共聚物及其化合物的热稳定性测定 - 变色法

[中文适用范围]： 本文件规定了两种测定基于氯乙烯均聚物和共聚物（以下简称PVC）的产品和化合物的热稳定性的方法，通过暴露时发生的变色程度来确定，形式为：片材，以升高温度。 这两种方法是： ——方法 A：油浴法； ——方法 B：烘箱法。 这些方法特别适用于测定 PVC 的耐热降解性，通过在标准条件下加热不同时间后颜色的变化来评估。 结果仅供比较，在测试彩色 PVC 材料时可能无法令人满意。 两种方法给出的稳定时间可能不相似，并且不能用于直接比较的目的。 [外文原描述]： This document specifies two methods for the determination of the thermal stability of products and compounds based on vinyl chloride homopolymers and copolymers (referred to simply as PVC in the following text) by the extent of the discoloration that occurs when they are exposed, in the form of sheet, to elevated temperatures. The two methods are: — Method A: Oil-bath method; — Method B: Oven method. These methods are particularly applicable to the determination of the resistance of PVC to degradation by heat, as assessed by the change in colour after different times of heating under standardized conditions. The results are comparative only, and can be unsatisfactory when coloured PVC materials are tested. The stability times given by the two methods might not be similar and cannot be used for direct-comparison purposes.