New Technology for Polyacrylic (ACM) Elastomers in Automotive Sealing Applications

Recent developments in polyacrylate elastomers (ACM) technology now offer potential solutions to the current weepage and noise transmission problems associated with silicone (VMQ) reported in the USA. The Non Oil Weepage (NOW) ideals have been in place in Europe and Japan. In Europe and Japan ACM have been used for more than 20 years as the sealing material of choice for rocker cover and oil pan gaskets. In the USA special design techniques have allowed easy to process VMQs to be used. Illustrative dynamic test data are shown for ACM. In addition, data from recent laboratory work using compressive stress relaxation techniques is given. A laboratory method that shows weepage-type problems is evaluated. The comparative testing includes air oven aging, engine oil aging, and compression set testing. Finally, new polyacrylic elastomer systems are described that offer cure characteristics more similar to VMQ-type polymers.