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Nitrile Rubber O-Rings (NBR)

Nitrile rubber 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 resistance 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. Nitrile has good mechanical properties when compared with other elastomers and high wear resistance.

Both o-rings and gaskets can be made from Nitrile materials.

Other Common Names: Acrylonitrile-ButadieneNBRBuna-NNitrile

Compound Info

ASTM D1418 DesignationNBR
ASTM D2000/SAE J200 Type, ClassBF, BG, BK, CH
Hardness (Shore A)40-90

Thermal Properties

Standard Min Temp.-40°F (-40°C)
Max Temp.250°F (121°C)
Orings Canada

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 fluids
Dilute acids, alkali and salt solutions at low temps.
Water (special compounds up to 212°F (100°C)

NOT Compatible

Fuels of high aromatic content (for flex fuels a special compound must be used)
Aromatic hydrocarbons (benzene)
Chlorinated hydrocarbons (trichloroethylene)
Polar solvents (ketones, esters, ethers, acetones)
Strong acids
Glycol based brake fluids
Ozone, weather, and atmospheric aging

Disclaimer: These are general guidelines only. All materials should be tested in your application.