Group R Compounds

Commercial names: Perbunan (Bayer AG), Hycar (B.F. Goodrich Chem. Co.), Krynac (Polymer Corp.), Elaprim (Montedison), JSR-N (Japan Synth. Rubber Co.).
This compound, generally denominated nitrilic rubber, has an important field of application in oil and fuel seals. It also presents good resistance to flexion and abrasion. The percentage of acrylonitrile content in the compound can have a value of between 20% and 50%, and this leads to huge variations in the chemical-physical behaviour of the rubber. In fact, with a greater acrylo-nitrile content the compound acquires remarkable properties of compatibility with fluids of mineral origin, but at the same time the elastic behaviour worsens at low temperatures. The NBR elastomer does not present good resistance to ageing on contact with oxygen and ozone, and the tendency for deterioration augments on the increase of the operating temperature. For better use, it is prudent to avoid direct contact between the rubber and the air, using it in immersion applications or maintaining a protective layer of lubricating oil.

Temperature table

Fluid compatibility table

The Elastotech code for this compound is: ME00XX/YY.
Approved compounds: ME099X/YY.