標準號：BS EN ISO 305-1999
中文標準名稱：塑料.與聚氯乙烯相關的含氯聚合物、共聚物及其混合物的熱穩定性的測定.色變法
英文標準名稱：Plastics - Determination of thermal stability of poly (vinyl chloride) related chlorine-containing homopolymers and copolymers and their compounds - Discoloration method
標準類型：G31
發布日期：1999/9/15 12:00:00
實施日期：1999/9/15 12:00:00
中國標準分類號：G31
國際標準分類號：83.080.20
適用范圍：1 This International Standard specifies two methods for the determination of the thermal stabil-ity 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 ex-posed, In the form of sheet, to elevated temper-atures. — Method A: Oil-bath method — Method B: Oven method 2 These methods are particularly applicable to the determination of the resistance of PVC to de-gradation by heat, as assessed by the change in colour after different times of heating under stand-ardized conditions. The results are comparative only, and may be unsatisfactory when coloured PVC materials are tested. 3 Method A is a simple method, which requires little expenditure on apparatus and permits materi-als to be tested almost In the absence of air. Method B requires a forced-air oven, in which the air flow Is adjusted to provide a sufficiently uniform temperature throughout the entire test area. This method is not applicable to materials that will cross-contaminate during oven exposure. The stability times given by the two methods may not be similar and cannot be used for direct-comparison purposes.