Acrylonitrile-Butadiene (NBR)

Nitrile rubber (NBR) is the general term for acrylonitrile butadiene copolymer. 

The acrylonitrile content of nitrile sealing compounds varies considerably (18% to 50%) and influences the physical properties of the finished material.The acrylonitrile content offers better resistance to oil and fuel, however, the elasticity and resistance to compression set is adversely affected. On the other hand, lower acrylonitrile content offers better low temperature performance but decreases resistance to oil and fuel. In view of these opposing realities, a compromise is often drawn and a copolymer with a medium acrylonitrile content is selected. 

NBR has good mechanical properties when compared with other elastomers 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) vegetable and mineral oils and greases.

• HFA, HFB and HFC hydraulic 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 (trichloroethylene).

• Polar solvents (ketone, acetone, acetic acid, ethylene-ester).

• Strong acids.

• Brake fluid with glycol base.

• Ozone, weather and atmospheric aging.