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Predictive life determination of elastomer compounds is becoming increasingly important due to shortened development time and reductions in cost. Currently to select rubber compounds the automotive industry uses different specifications. In the USA and in most European countries these specifications are based on ASTM D 2000, and in Japan the specifications are based on JIS-B 2402. These test methods are mostly related to single point measurement. Unfortunately, from decades of long experience, engineers know that the real life time of elastomeric parts cannot be derived from these currently used specifications and test methods. During investigation of the sealing mechanism performed by Chicago Rawhide for many years the basic rubber properties responsible for seal life have been established. Using both standard ASTM and new methods for measuring the change in rubber properties during oil immersion aging, correlation were established between the kinetics of such changes and seal life.

Two new methods will be presented to measure rubber and seal elasticity - Recovery from Bending (RFB) and Loss of Seal Interference (LOSI). It will be demonstrated, the kinetics of rubber elasticity change during immersion in oil with aeration and oil change for different rubber compounds as NBR, HNBR, ACM, AEM, FKM and VMQ. Using the kinetics of Recovery From Bending, the estimation of seal life can be done.