Buna O-Rings

Buna (Nitrile or NBR) O-rings: general purpose sealing

Buna O-rings, also known as nitrile or NBR O-rings, offer excellent sealing and mechanical properties at a low cost. Buna O-rings have resistance to common lubricants and are recommended for crude oil, gasoline, propane, petroleum oils and water. Buna O-rings are used in applications for engines, gearboxes, aircraft pumps and water.

Buna O-Rings are used as face-to-face and shaft seals, and allow rotary and linear movement. Nitrile O-rings have good tear and abrasion resistance with operating temperatures from -30°F to 250F° (-57°C to 121°C), which can be higher with special compounds.Buna-N Nitrile O-Rings

Buna/nitrile/NBR O-rings are available in different colors, durometers and compounds for specific application, sealing and aesthetic requirements. 

Parker Buna O-rings are recommended for petroleum-based oils and fluids, mineral oils, ethylene glycol base fluids, silicone and diester base lubricants, air, natural gas and water under 150°F (66°C).  A common Parker nitrile O-ring compound is N0674 Black.

Buna/nitrile/NBR O-rings have limitations to ozone, sunlight and weathering, and aren't good in strong acids, aircraft and automobile brake systems or ketones. Parker's nitrile rubber (NBR) acrylonitrile content can vary considerably (18% to 50%). The higher acrylonitrile content results in better oil and fuel resistance, although elasticity and compression set resistance may be adversely affected. NBR has good mechanical and wear resistance properties.

• Heat and wear resistance
• Up to 212°F (100°C) with shorter life @ 250°F (121°C)
• Cold flexibility, depending on compound, between -70 and -30°F (-57 and -34°C )
• 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 hydraulic fluids
• Dilute acids, alkali and salt solutions at low temperatures
• Water (special compounds up to 212°F (100°C)
• Used for General Purpose, MIL-G-21569 CL 1, UL Listed