GB/T 9871-2008 in English

本标准规定了三种测量试样在给定伸长状态下应力变化的方法，目的是测定橡胶硫化胶的老化性能。 本标准等同采用ISO 6914：2004 《硫化橡胶或热塑性橡胶老化性能的测定　拉伸应力松弛试验》（英文版）。
本标准代替GB 9871-1988《硫化橡胶老化性能的测定（拉伸应力松弛试验）》。
本标准与GB 9871-1988的主要技术差异如下：
———增加了引言部分，删除了原标准的第３ 章；引言是对本标准试验方法与原理的一个概述，内容很重要但不是标准规范性的部分；
———增加了范围内容的描述，对每种方法进行了细节性的陈述（见第１章）；
———规范性引用文件增加了导语，引用标准也有所不同（见第２章）；
———测力和拉伸精度由２％修改为±１％（１９８８年版的４．１和４．２；本版的３．１和３．２）；
———修改了试样尺寸的规定，厚度均匀即可，对宽度和长度未作硬性规定（１９８８年版的５．２；本版的
４．１）；
———修改了试样数量的规定，依据试验目的可调整与选择（１９８８年版的５．３；本版的４．２）；
———增加了可选取的老化温度，并提高了控温精度（１９８８年版的７．２；本版的６．２）；
———修改了试验结果的表述（１９８８年版的第９章；本版的第８章）；
———增加了规范性附录，试验仪器的校准（本版的附录Ａ）。

Scope

This standard specifies three methods for measuring the stress change of a specimen under a given elongation state, with the purpose of determining the aging properties of rubber vulcanizates. Method A is for measurements under continuous strain conditions. Method B is the preferred method for measurements under intermittent strain conditions. In both cases A and B, the stress at the aging temperature is recorded using a stress relaxometer. Method C can be used instead of Method B for measurements under intermittent strain conditions. In method C, the specimen is removed from the aging environment and the stress is measured at standard laboratory temperature. Measurements at a single aging high temperature can be used for quality control purposes, such as the degree of heat aging resistance. According to the method described in GB/T 20028, measurements are made at a range of temperatures to predict long-term aging performance, which can be used for research and development purposes. There is no interpolation between the three methods, and the method used depends on the purpose of the experiment.