1.1 本试验方法提供了一种方法，用于估算模塑聚丙烯在有空气存在的情况下，使用强制通风烘箱对热加速老化的耐受性。 1.2 本试验方法确定的稳定性与材料在不同环境条件下的适用性没有直接关系，不得用于预测性能。 注1: 本试验方法中规定的热水平被视为足够严重，足以在合理的时间内导致商业级热稳定聚丙烯失效。如果需要，可以采用较低的温度来评估热稳定性较低的聚丙烯的性能。 1.3 以国际单位制表示的数值应视为标准。 括号中的值仅供参考。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 注2: 本试验方法与ISO 4577-1983在技术上相似，但在试样制备、试样厚度、烘箱中气流变化次数的测量以及每小时所需的换气次数方面有所不同。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 在本试验方法的恶劣条件下，试样的降解速度取决于受检聚丙烯材料的耐热性。 5.2 本试验方法的热水平被认为足够严重，足以在合理的时间内导致商业级热稳定聚丙烯失效。如果需要，可以采用较低的温度来评估热稳定性较低的聚丙烯材料的性能。 5.3 本试验方法中描述的试样旋转技术提供了聚丙烯寿命-温度关系的估计。如果该试验方法在同一材料的不同温度下进行，则可以更可靠地估计寿命- 测定了聚丙烯的温度关系。该试验方法可在多种温度下进行，并通过使用阿累尼乌斯关系来解释数据，方法是绘制失效时间对数与温度的倒数，单位为开尔文（K）。为此，建议温度范围为100至150°C，间隔为10°C。 5.4 根据规定的试验方法确定的稳定性与化合物在不同条件下的适用性没有直接关系。 5.5 热老化的试样旋转技术增加了所有试样以类似方式暴露的可能性，并将烘箱中温度梯度的影响降至最低。

1.1 This test method provides a means for estimating the resistance of polypropylene, in molded form, to accelerated aging by heat in the presence of air using a forced draft oven. 1.2 The stability determined by this test method is not directly related to the suitability of the material for use when different environmental conditions prevail and shall not be used to predict performance. Note 1: The specified thermal levels in this test method are considered sufficiently severe to cause failure of commercial grades of heat-stable polypropylene within a reasonable period of time. If desired, lower temperatures can be applied to estimate the performance of polypropylene with lower heat stabilities. 1.3 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Note 2: This test method and ISO 4577–1983 are technically similar but different in preparation of test specimens, thickness of test specimen, measurement of the number of air flow changes in the ovens, and the number of air changes per hour required. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Under the severe conditions of this test method, the specimens undergo degradation at a rate that is dependent upon the thermal endurance of the polypropylene material under examination. 5.2 The thermal level of this test method is considered sufficiently severe to cause failure of commercial grades of heat-stable polypropylene within a reasonable period of time. If desired, lower temperatures can be applied to estimate the performance of polypropylene materials with lower heat stability. 5.3 The technique of specimen rotation described in this test method provides an estimate of the life-temperature relationship of polypropylene. If this test method is conducted at different temperatures on the same material, a more reliable estimate of the life-temperature relationship of polypropylene is determined. This test method can be conducted at several temperatures and the data interpreted through use of the Arrhenius relation, by plotting the logarithms of times to failure against the reciprocals of the temperatures in kelvins (K). Temperatures in the range from 100 to 150°C, with intervals of 10°C, are suggested for this purpose. 5.4 The stability as determined under the prescribed test method is not directly related to the suitability of the compound for a use where different conditions prevail. 5.5 The specimen rotation technique of thermal aging increases the probability that all specimens will be exposed similarly and that the effect of temperature gradients in an oven will be minimized.