This International Standard specifies a number of methods of determining the dimensional changes in test pieces of vulcanized or thermoplastic rubber during and after tensile loading for relatively short periods under constant elongation or constant loading.
The constant-elongation test is intended to measure the ability of rubbers to retain their elastic properties after extension, at a standard laboratory temperature, to a specified strain which is maintained for a specified time at the same or at a specified higher temperature and then released at the test temperature or at the standard laboratory temperature.
The constant-load test specifies a method for the determination of elongation, creep and tension set of rubbers subjected to a constant load at standard laboratory temperature.
The test methods are intended to measure the elastic properties of rubber in the hardness range 20 IRHD to 94 IRHD.
The creep measurement is not recommended for product design or the evaluation of low-creep materials. For these, reference should be made to ISO 8013. No agreement between the results of this test or those of ISO 8013 should be inferred.
NOTE The constant-load test is primarily intended for the measurement of state of cure and the quality control of thin-walled products. An increase in the state of cure or degree of crosslinking is usually reflected in a decrease in set, creep or crosslinking.