BS EN ISO 305-1999 塑料.与聚氯乙烯相关的含氯聚合物、共聚物及其混合物的热稳定性的测定.色变法

标准号：BS EN ISO 305-1999
中文标准名称：塑料.与聚氯乙烯相关的含氯聚合物、共聚物及其混合物的热稳定性的测定.色变法
英文标准名称：Plastics - Determination of thermal stability of poly (vinyl chloride) related chlorine-containing homopolymers and copolymers and their compounds - Discoloration method
标准类型：G31
发布日期：1999/9/15 12:00:00
实施日期：1999/9/15 12:00:00
中国标准分类号：G31
国际标准分类号：83.080.20
适用范围：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.