Ethylene acrylic elastomers (AEM) environmentally friendly sealing material for a broad range of applications

摘要

Ethylene acrylic elastomers (AEM) were introduced in 1974 and they are now used in many applications in the automotive industry where a combination of oil resistance, high temperature resistance and excellent damping properties is required. With the continuing trend of increasing under-hood temperatures and the increasing use of new aggressive automotive oils and fluids, the elastomers used in many applications have had to be replaced by higher specification materials. This is particularly so in seals and gaskets applications where AEM has replaced many lower temperature elastomers to give longer-term performance. In addition new regulations are being introduced that limit or eliminate the use of environmentally critical substances. The existing range of AEM polymers and their associated compounds do not incorporate halogens, heavy metals or other hazardous materials and therefore can offer many solutions for new demanding oil seal applications. Developments are underway to modify the AEM offering in order to extend its performance range. Product modifications are directed at enhancing dry heat resistance, low temperature flexibility, productivity and service fluid resistance without sacrificing existing performance characteristics. Reviewed are the properties of commercially available AEM grades, new applications and developments as well as the results of new test methods such as compressive stress relaxation and permeation.