NITRILE (NBR)

Nitrile is the most widely used elastomer in the seal industry. The popularity of nitrile is due to its excellent resistance to petroleum products and its ability to be compounded for service over a temperature range of -60°F to 250°F.

Nitrile is a copolymer of butadiene and acrylonitrile. Variation in proportions of these polymers is possible to accommodate specific requirements. An increase in acrylonitrile content increases resistance to heat plus petroleum base oils and fuels but decreases low temperature flexibility. Military AN and MS O ring specifications require nitrile compounds with low acrylonitrile content to insure low temperature performance.

Nitrile provides excellent compression set, tear, and abrasion resistance. The major limiting properties of nitrile are its poor ozone and weather resistance and moderate heat resistance, but in many application these are not limiting factors.

Temperature Range (dry heat)

low

high

-30 °F
-35 °C

250 °F
120 °C

Application Advantages

» excellent compression set,
» superior tear resistance
» abrasion resistance

Application Disadvantages

» poor weather resistance
» moderate heat resistance

Modifications

» acrylonitrile content (ACN) from 18% to 50%
» peroxide vs. sulfur donor cure system
» XNBR improved wear resistance formulation

Primary Uses

Specialized Applications

O-rings, rubber seals and custom molded rubber components for:
» Oil resistant applications
» Low temperature applications
» Fuel systems, automotive, marine, and aircraft
» General Industrial Use

» NBR NSF standard 61 for potable water applications
» NBR WRc, KTW water applications
» NBR FDA whitelist compounds