Nitrile rubber (NBR), also know as Buna-N, is the general term for acrylonitrile butadiene terpolymer. The acrylonitrile content of nitrile sealing compounds varies considerably (18% to 50%) and influences the physical properties of the finished material.

The higher the acrylonitrile content, the better the resis¬tance to oil and fuel. At the same time, elasticity and resistance to compression set is adversely affected. In view of these opposing realities, a compromise is often drawn, and a medium acrylonitrile content selected. NBR has good mechanical properties when compared with other elas¬tomers and high wear resistance. NBR is not resistant to weathering and ozone.

• Heat resistance
  Up to 100°C (212°F) with shorter life @ 121°C (250°F)
• Cold flexibility
  Depending on individual compound, between -34°C and -57°C (-30°F and -70°F)
• Chemical resistance
  • Aliphatic hydrocarbons (propane, butane, petroleum oil, mineral oil and grease, diesel fuel, fuel oils) veg¬etable and mineral oils and greases
  • HFA, HFB and HFC fluids
  • Dilute acids, alkali and salt solutions at low temperatures
  • Water (special compounds up to 100°C) (212°F)

Not compatible with

• Fuels of high aromatic content (for flex fuels a special compound must be used)
• Aromatic hydrocarbons (benzene)
• Chlorinated hydrocarbons (trichlorethylene)
• Polar solvents (ketone, acetone, acetic acid, ethylene-ester)
• Strong acids
• Brake fluid with glycol base
• Ozone, weather and atmospheric aging