What is Buna-N Rubber?

What Is Buna-N Rubber and Why Is It Ideal for Air Fittings?

Buna-N, also known as nitrile rubber, is a synthetic rubber compound renowned for its resistance to oils, fuels, and petrochemicals. But what makes it so effective, and why is it the preferred seal material in pneumatic air systems?

Understanding the Problem Buna-N Solves

Most standard rubber compounds degrade when exposed to oil. When a rubber material absorbs liquid hydrocarbons, it softens and swells. This is due to the molecular makeup of typical rubber, open bonds and structures that allow oils to infiltrate and weaken the material. The result? Premature failure of gaskets, seals, and other components.

That’s where Buna-N comes in.

Why Buna-N Excels

Buna-N is made with a high acrylonitrile content, which gives it powerful oil- and water-resistant properties. Acrylonitrile is both hydrophobic (repels water) and oleophobic (repels oils), so it resists molecular absorption and breakdown when exposed to harsh liquids. This makes it incredibly durable in environments where most rubbers fail.

Why Are Buna-N Seals Used in Air Fittings?

In shop and industrial settings, pneumatic tools and air systems require consistent lubrication with oil to reduce friction and wear. Buna-N is the ideal material for sealing components, such as air couplers, fittings, and hoses, because it stands up to the regular presence of lubricating oils.

Its resilience prevents leaks, extends equipment lifespan, and reduces maintenance frequency.

Maintenance Tip

While Buna-N offers superior oil resistance, it's not invincible. Some petrochemicals can wear it down over long periods. Regular inspection of your air system for leaks or wear, and timely replacement of seals, helps ensure long-term performance and safety.

Buna-N rubber is an essential material in the world of industrial and automotive tools, especially where oil exposure is frequent. Its unmatched resistance to fuel and oil makes it the go-to choice for shop air systems. Next time you see Buna-N seals in your pneumatic tools or air fittings, you’ll know exactly why.