Nitrile rubbers form the most important group of elastomers for general sealing use.
Chemically, Nitrile is a copolymer of butadiene and acrylonitrile content, typically varying between about 18% and 48%.
Nominal designations are low, medium and high Nitrile. Resistance to petroleum based oils and hydrocarbons increases with increasing Nitrile content, but at the same time low temperature flexibility decreases. In order to obtain good low temperature performance with Nitrile rubbers it usually necessary to sacrifice some high temperature fuel and oil resistance.
Nitrile rubbers have good physical characteristics and are superior to most other rubbers. They are not particularly resistant to ozone, weathering and sunlight, but their properties in this respect can be improved by compounding. Due to their susceptibility to ozone attack Nitrile rubber seals should not be stored near any possible source of ozone (ex. near an electric motor or electrical equipment), or in direct sunlight.