Elastocon offers equipment for testing rubber according to the methods compression set (ISO 815) and tension set at constant elongation (ISO 2285).
Compression set (ISO 815)
Sättning Compression set is the permanent set that occurs when rubber has been compressed and then unloaded and allowed to recover.
The testing is normally done on standardised cylindrical test pieces. The test pieces are normally compressed by 25 % in a rig with smooth polished surfaces. The compression set rig, with test samples, is stored in an ageing cabinet at increased temperature, for periods from 24 hours up to several weeks. The rig is taken from the cabinet and the samples are unloaded and are allowed to recover for 30 minutes before testing. Sometimes an alternative method is used where the samples are allowed to cool in the compressed state. This normally gives higher compression set values.
Read more: Compression set rig, EV 03
Tension set at constant elongation (ISO 2285)
If a rubber sample is kept elongated for a period of time and is then unloaded, it will not retract completely to its initial length. This is called tension set.
For constant elongation testing, the test pieces are elongated, normally to 100 % and are kept elongated, often at increased temperature, from 24 hours to several weeks. When the samples have been taken out of the oven they are left to cool in the elongated state after which they are unloaded and allowed to recover for 30 minutes before measuring.
