1.1 本标准规定了两种方法，用于测定硫化橡胶或热塑性弹性体试样施加的反作用力的减少，该试样在规定的时间和温度条件下以恒定变形压缩。 1.2 本文件是在空气和液体中测试的基础上编制的。 1.3 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。 1.4 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 当对橡胶施加恒定应变时，保持该应变所需的力不是恒定的，而是随时间而减小；这种现象称为力衰减（应力松弛）。相反，当橡胶受到恒定应力时，变形会及时增加；这种行为称为爬行。这些现象在密封件和垫片等橡胶制品中具有实际意义。 5.2 力衰减的过程可能是物理或化学性质的，在所有正常条件下，这两个过程将同时发生。然而，在环境温度或低温和/或短时间内，力衰减主要由物理过程控制，而在高温和/或长时间内，化学过程占主导地位。因此，外推时间/力衰减曲线以预测比试验所涵盖的时间长得多的时间后的力衰减，或使用高温试验作为加速试验来提供低温下力衰减的信息，都是不安全的。 5.3 除了需要在力衰减试验中指定温度和时间间隔外，还需要指定试样的初始应力和之前的机械历史，因为这些也可能影响测得的力衰减，尤其是在含有填料的橡胶中。

1.1 This standard specifies two methods for determining the decrease in counterforce exerted by a test specimen of vulcanized rubber or thermoplastic elastomer which has been compressed at a constant deformation under specified conditions of time and temperature. 1.2 This document was developed based on testing in air and liquids. 1.3 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. 1.4 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 When a constant strain is imposed on rubber, the force necessary to maintain that strain is not constant but decreases with time; this phenomenon is called force decay (stress relaxation). Conversely, when rubber is subjected to a constant stress, an increase in the deformation takes place in time; this behavior is called creep. These phenomena are of practical significance in rubber articles, such as seals and gaskets. 5.2 The processes responsible for force decay may be either physical or chemical in nature, and under all normal conditions both processes will occur simultaneously. However, at ambient or low temperatures and/or short times, force decay is dominated by physical processes, while at elevated temperatures and/or long times, chemical processes are dominant. Hence, it is neither safe to extrapolate time/force decay curves in order to predict force decay after periods considerably longer than those covered by the test, nor to use tests at higher temperatures as accelerated tests to give information on force decay at lower temperatures. 5.3 In addition to the need to specify the temperature and time-intervals in a force decay test, it is also necessary to specify the initial stress and the previous mechanical history of the test specimen, since these may also influence the measured force decay, particularly in rubbers containing fillers.