Nitrile (often referred to as Buna-N) is the most commonly
used elastomer in the seal industry and is a copolymer of
two monomers; acrylonitrile (ACN) and butadiene. The
properties of this elastomer are ruled by the ACN content
which is broken down into three classifications:
- High Nitrile: >45% ACN content
- Medium Nitrile: 30 – 45% ACN content
- Low Nitrile: <30% ACN content
The higher the ACN content, the better the elastomers
resistance to hydrocarbon oils. With lower ACN content, the
material offers better flexibility at low temperatures.
Medium nitrile is, therefore, the most widely specified due
to its good overall balance in most applications.
Typically, nitrile rubber can be compounded to work over a
temperature range of -35°C to +120°C and is superior to most
other elastomers in regard to compression set, tear and
abrasion resistance.
Nitrile rubbers posses excellent resistance to oil-based
fluids, vegetable oils, greases, water and air.