What Is Buna-N?

Buna-N, (or Buna)also known as Nitrile Rubber (NBR), is a synthetic elastomer that
resists oils, fuels, and many petroleum-based fluids. Because of this
compatibility, manufacturers use it extensively in oil and gas equipment,
sealing systems, and fluid-handling applications.

Material Composition

Manufacturers produce Buna-N by combining acrylonitrile and butadiene polymers.
By adjusting the acrylonitrile content, they can balance flexibility, chemical
resistance, and temperature performance to suit different applications.

Common Applications

Manufacturers and equipment suppliers use Buna-N in a variety of sealing and
fluid-containment components, including:

• O-rings and seals
• Valve seats and valve seals
• Gaskets and packing materials
• Pump components
• Hoses and flexible connectors
• Tank and piping system seals

Performance Characteristics

Buna-N performs particularly well in contact with crude oil, diesel fuel,
hydraulic fluids, lubricating oils, and many hydrocarbon-based products.
Additionally, it provides good abrasion resistance and maintains flexibility
under normal operating conditions. However, it does not perform well when
exposed to ozone, weathering, or certain aggressive chemicals.

Advantages

• Provides excellent resistance to petroleum-based fluids
• Offers good wear and abrasion resistance
• Maintains flexibility and sealing performance under moderate temperatures
• Costs less than many specialty elastomers
• Works well in a wide range of oilfield applications

Limitations

• Does not perform well in strong oxidizing chemicals
• Can degrade when exposed to ozone, sunlight, and weathering
• Provides lower temperature resistance than materials such as Viton® or silicone
• May swell or deteriorate in certain solvents and chemicals

Typical Temperature Range

Buna-N generally performs well between approximately -40°F and 250°F
(-40°C and 121°C), although the exact range depends on the specific compound
formulation.

Summary

Buna-N is a nitrile-based synthetic rubber widely used for seals, O-rings,
gaskets, valve components, and other fluid-handling applications. Its strong
resistance to oils and hydrocarbons makes it one of the most common elastomers
used throughout the oil and gas industry.