Nitrile (Buna-N)
Trade Names:
- Nipol . . . Zeon
- Krynac . . . Bayer Polymer
- Nysyn . . . DSM Elastomers
- Chemigum . . . Eliokem
ASTM D1418 Designation: NBR
ASTM D2000/SAE J200 Type, Class: BF, BG, BK, CH
Apple Compound Designation: BN
Standard Color: Black
Description: Presently the seal industry's most widely used and economical elastomer, Nitrile combines excellent resistance to petroleum-based oils and fuels, silicone greases, hydraulic fluids, water and alcohols, with a good balance of such desirable working properties as low compression set, high tensile strength, and high abrasion resistance. Use of Carboxylated Nitrile can have superior abrasion resistance, while still having improved oil resistance.
Key Use(s): Oil resistant applications of all types. Low temperature military uses. Off-road equipment. Automotive, marine, aircraft fuel systems. Can be compounded for FDA applications.
Temperature Range
Standard Compound: -40° to +257°F (Dry Heat Only)
Special Compound: -76° to +275°F
Hardness (Shore A): 40 to 90.
Features: Comprised of the copolymer butadiene and acrylonitrile, in varying proportions. Its performance characteristics may be varied over a working temperature range of -65°F to +300°F.
Increasing acrylonitrile content gives Nitrile its better resistance to petroleum-based oils and hydrocarbon fuels, enhancing resistance to the degrading effects of heat, at a cost of reduced low temperature performance. It is also good with silicone greases and oils.
Conversely, decreasing acrylonitrile, while increasing butadiene content, provides better low temperature flexibility a characteristic most often required by Air Force-Navy (AN) and Military Standard (MS) O-ring specifications.
A carboxylated version of the high-acrylonitrile butadiene copolymer (XNBR) is also available for applications requiring enhanced abrasion resistance.
Limitations:Increasing acrylonitrile content improves oil resistance at a cost of reduced low temperature performance. The lowest levels of ozone attack nitrile materials.