Buna-N O-Rings (NBR) Nitrile

Nitrile Buna-N (NBR) O-Rings Material Description

Nitrile Buna-N (NBR) o-rings are one of the most common and widely used sealing materials because of its excellent sealing and mechanical properties at a low cost. Nitrile offers excellent tensile strength, abrasion resistance, tear resistance, and compression resistance. Optimal environments include petroleum oils and fuels, silicone oils and greases, propane, ethylene glycol, butane, vegetable, mineral oils and greases, dilute acids, and water and steam applications (below 212°F).

Engineered Seal Products has the expertise and inventory for your nitrile Buna-N (NBR) o-ring applications. For over 50 years, ESP has been the leading engineering, quality, and supply chain choice for both standard and custom sealing applications. A seal, no matter the application, has to do just that.

Also Know As:

Nitrile, Buna-N, acrylonitrile-butadiene terpolymer, Breon, Butakon®, Chemigum®, Hycar®

Nitrile Buna-N (NBR) Advantages:
  • Excellent tensile strength
  • Abrasion resistance
  • Tear resistance
  • Compression resistance

Optimal environments: petroleum oils and fuels, silicone oils and greases, propane, ethylene glycol, butane, vegetable, mineral oils and greases, dilute acids, water and steam applications (below 212°F).

Nitrile Buna-N (NBR) Disadvantages:
  • Low resistance to ozone, sunlight, and weathering

Incompatible with benzene, toluene, xylene, halogen derivatives (carbon tetrachloride, trichloroethylene), ketones (MEK, acetone), phosphate ester hydraulic fluids (Skydrol, Pydraul), strong acids and glycol.

There are special formulations available to nitrile compounds that will help with weather and ozone resistance where nitrile is otherwise preferred.

ESP Nitrile Buna-N (NBR) Compounds:

ESP Compound Number Datasheet Hardness (Shore A) Low Temp High Temp Color Features
ESP-1001-N70 PDF 70 +- 5 --- --- Black General purpose.
ESP-1002-N90 PDF 90 +- 5 --- --- Black General purpose.
ESP-N8018 PDF 70 +- 5 --- --- Black FDA - 3A approved.
ESP-N8008 PDF 70 +- 5 -40 60 Black UL Recognized

Nitrile Buna-N (NBR) Material Properties

Nitrile Buna-N (NBR) Material Temperature Range:

Heat Resistance: Up to 212°F (100°C) with shorter life @ 250°F (121°C)

Cold Flexibility: Depending on individual compound, between -30°F and -70°F (-34°C and -57°C).

Normal Recommended Temperature Range Normal recommended temperature range

Extended Temperature Range Extended Temperature Range for short term only

PDF O-Ring Temperature Range Chart

Abrasion Resistance Good
Chemical Resistance Fair / Good
Cold Resistance Good
Heat Resistance Good
Oil Resistance Excellent
Ozone Resistance Poor
Tensile Strength Fair / Good
Water/Steam Resistance Fair / Good

Material properties & Temp ranges based on Parker o-Ring Handbook (ORD 5700) recommendations.

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ASTM Designation
Shelf Life
15 Years
Hardness (Shore A) Range
40 - 90

Temperature ranges will apply to the majority of media for which the material is potentially recommended. With some media however, the service temperature range may be significantly different. ALWAYS TEST UNDER ACUTAL SERVICE CONDITIONS.

ESP’s shelf life recommendation is based on the ARP 5316 standard and intended to be utilized by those organizations who do not already have specific recommendations for the control of elastomeric seals. It should be noted that the packaging of the elastomeric seals prior to assembly into a product is an integral part of the controlled storage procedure. It provides a positive means of product identity from the time of manufacture, to the time of assembly.