Buna O-Rings | Nitrile O-Rings

Buna O-rings are made from nitrile, a synthetic rubber with excellent sealing properties. Also referred to as nitrile O-rings or NBR O-rings, Buna O-rings come in a variety of sizes and have a wide range of uses. As a material, nitrile features good resistance to most chemicals, oils, alkaline, and acids. For example, Buna O-rings feature good chemical resistance against:

  • Mineral and vegetable oils, petroleum greases
  • Aliphatic hydrocarbons
  • Alcohols
  • Hydraulic fluids (HFA, HFB, HFC types)
  • Dilute acids, alkalis, and solvents

The versatility and beneficial properties offered by nitrile materials make Buna O-rings useful for sealing gaskets, oil tanks, propane tanks, fuel tanks, among many other products. Here are some additional properties:

  • Temperature range: -40° F to 250° F
  • Applications: Coldwater, petroleum oils, vegetable oils, silicone oil and grease, hydraulic fluids
  • Avoid use with: Hydrocarbons, chlorinated hydrocarbons, aromatic fuels, sunlight, weathering, ozone, polar solvents, glycol brake fluids, fire/flame
  • Hardness: 40 to 90 Shore A are available
  • High tensile strength
  • Good resistances to heat, abrasion, water and steam
  • May be internally lubricated for easier installation and reduced friction
  • Low permeability

Nitriles may be formulated for use in specialized applications or to meet certain industry standards. Here are some examples:

  • Combining nitrile rubber with polyvinyl chloride (PVC) creates an NBR-PVC blend material with high resistances to fuel, ozone, and weather. 
  • Nitriles may also be fabricated using only white-list ingredients in accordance with 21.CFR.177.2600 to create seals safe for use in food-grade applications.
  • Nitriles approved by the National Sanitation Foundation (NSF) are safe for use in potable water applications. 
  • Underwriters Laboratories (UL) listing UL157 covers offers specific quality standards for nitrile gaskets and seals. 

Buna O-Ring Customization Examples

At Allied Metrics, we offer a wide variety of customization options for our O-rings. Some of our most common customizations include:

  • Durometer or color hardness
  • Surface or internal lubrication
  • Custom chemical resistance
  • Increased temperature performance
  • EMI shielding RFI conductive
  • Treatments and coatings
  • Color customization: black, brown, green, white, rust, yellow, blue, red, orange, and gray are available, in addition to any customer-assigned color
  • Specialized, labeling, bagging, marking, kitting or inspection
  • FDA, NSF, USP, NORSOK M-170, and military compliant

Buna O-Rings at Allied Metrics

At Allied Metrics, we have been specializing in metric hydraulic, pneumonic, and oil seals since 1989. We pride ourselves in delivering high-quality products and services for our clients on every order. To learn more about Allied Metrics, visit our about us page. For more information about our products and capabilities, please contact us or request a quote today!