NITI Ventures | Nitrile (NBR)

Nitrile (NBR) O-Rings

Nitrile rubber, also known as NBR or Buna-N, is one of the most commonly used sealing elastomers for general industrial service. It is widely chosen for petroleum-based fuels, lubricants, greases, hydraulic fluids, and other oil-resistant applications because it offers a strong balance of performance, availability, and cost-effectiveness.

Typical temperature rangeAbout -30°C to +100°C typical. Special compounds can extend higher in some applications.

Other namesNBR, Nitrile, Buna-N

Hardness optionsCommon hardnesses include 60, 70, 75, 80, and 90 Shore A. Most general-purpose O-rings are often supplied in 70 Shore A.

Compliance optionsDepending on compound, NBR may be available in FDA-compliant options, with REACH / RoHS declarations, and other application-specific compliance.

Best used for

Mineral oils and greases
Hydraulic fluids
Diesel and fuel systems
General industrial sealing
Pneumatic and hydraulic service

Key advantages

Good resistance to oils and fuels
Good mechanical strength
Good abrasion resistance
Cost-effective and widely available

Performs well in

Petroleum-based oils and fuels
Mineral oils
Greases
Hydraulic oils
Diesel
Many aliphatic hydrocarbons

Use with caution or avoid

Ozone and outdoor weather exposure
Sunlight
Hot water and steam
Brake fluids
Ketones
Strong oxidizing chemicals

Typical applications

Hydraulic cylinders
Pneumatic systems
Fuel handling equipment
Automotive seals
Pumps, compressors, and gearboxes
General maintenance and replacement seals

Common industries

Automotive
Fluid power
Manufacturing
Oil and gas support equipment
Agricultural machinery
General engineering

When to choose Nitrile (NBR)

Choose Nitrile when you need a reliable general-purpose sealing material with good oil and fuel resistance, economical performance, and broad industrial availability.

When not to choose Nitrile (NBR): Avoid Nitrile for strong ozone exposure, weathering, hot steam, aggressive incompatible chemicals, or very high-temperature service where FKM or EPDM may be a better fit.

Selection guide

This is a practical selection guide. Final material choice should always be checked against actual fluid, temperature, pressure, movement, environment, and any approval requirement for the exact compound.

Other materials

Need help selecting the right material?

Tell us your fluid, temperature, pressure, size, and whether the seal is static or dynamic. We can help review the most suitable starting options before final size and compound selection.