1. Low temperature retraction temperature. The seal is stretched to a certain length, then fixed, rapidly cooled to below the freezing temperature, reached equilibrium and then released, and heated at a certain speed. The temperature at which the recording material was retracted by 10%, 30%, 50%, and 70% was represented by TR10, TR30, TR50, and TR70, respectively. The material standard uses TR10 as an indicator, which is related to the brittleness temperature of the rubber.
2. Low temperature flexibility. After the material is frozen at a certain low temperature for a predetermined period of time, it is reciprocally bent at a predetermined angle. At this time, the sealing ability of the rubber seal after the repeated action of the dynamic load at a low temperature was examined.