Rubber is an ideal sealing material due to its ability to retain its shape after deformation.Hydrogenated Nitrile Butadiene Rubber(HNBR)is a prime candidate for sealing applications where relatively high temperatures and aggressive fluids,such as those found in automotive,are present.A peroxide cure is implemented in HNBR for applications where long-term compression set is critical. Studies have shown that in the presence of oxygen,part geometry has an influence on its measured compression set,and that thin sectioned articles are observed to have worse compression set resistance than thicker geometries.This is because as the surface-to-volume ratio of the part increases,thermal oxidation through the bulk of the part will increase,resulting in decreased compression set performance.While this phenomenon is evident in a variety of elastomers,the impact on compression set is further amplified in peroxide cured HNBR when surface-to-volume ratios approach values that are commonly observed in thin sectioned articles such as O-rings and gaskets. To remedy the impact of part geometry on performance,ZEON has developed a product that better maintains compression set when testing is performed on gaskets,O-rings,or other thin article applications.This solution is an HNBR polymer with an additional cure site monomer that allows for a diamine cure.Diamine cured HNBR provides superior properly retention and compression set when compared to other conventional cure systems.ZEON has named this class of elastomer High Performance Zetpol~R(HP-Zetpol).
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