The Selection of Elastomer Compounds through Correlation of Rubber Properties to Seal Life

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. The paper describes the rubber properties, test methods and test procedures which can help engineers to develop and select rubber compounds without using the dynamic seal bench test.