What Are the Pros and Cons of NBR?

Nitrile butadiene rubber (NBR)¹ is a synthetic rubber widely used in various industrial applications, particularly for seals, gaskets, and O-rings. Known for its excellent resistance to oils and fuels, NBR is a popular choice in the automotive, aerospace, and oil industries. However, like any material, it comes with its own set of advantages and disadvantages. In this article, we’ll explore the pros and cons of NBR to help you decide if it’s the right material for your application.

NBR is a versatile material with excellent oil and fuel resistance, but it has its limitations, including poor resistance to heat and ozone. Here's a deeper look at its pros and cons.

What is NBR?

NBR, or nitrile butadiene rubber, is a copolymer made from the combination of acrylonitrile (ACN) and butadiene. The higher the ACN content, the better the material's resistance to oils, fuels, and solvents, but the flexibility and low-temperature performance may be compromised. NBR is commonly used in sealing products like O-rings, gaskets, and fuel hoses, making it a key material in automotive, chemical, and aerospace applications.

NBR is a synthetic rubber made from acrylonitrile and butadiene, offering excellent resistance to oils and fuels, making it ideal for sealing applications in various industries.

Pros of NBR

1. Excellent Oil and Fuel Resistance²

One of the primary advantages of NBR is its superior resistance to oils, fuels, and many other chemicals. It is highly effective at maintaining its integrity when exposed to petroleum-based products, making it an ideal choice for automotive, aerospace, and industrial applications where fuel exposure is common.

NBR’s superior resistance to oils, fuels, and chemicals makes it an ideal material for automotive and industrial sealing applications.

2. Good Mechanical Properties

NBR offers good mechanical strength, making it durable and resistant to wear and tear. It has high tensile strength, elongation, and tear resistance, which are essential for seals and gaskets that need to endure repeated stress and movement.

NBR’s high mechanical strength, tensile strength, and tear resistance make it durable, especially in dynamic sealing applications.

3. Affordable and Versatile

NBR is relatively cost-effective compared to other elastomers with similar properties. It’s available in a wide range of formulations to suit different applications. Whether you need a soft, flexible rubber for seals or a harder compound for industrial gaskets, NBR can be tailored to meet specific needs.

NBR is an affordable and versatile material, offering a wide range of formulations for different applications, making it accessible for various industries.

4. Good Low-Temperature Performance

NBR is known to retain its flexibility at lower temperatures, especially when compared to other materials like EPDM or SBR. This makes it an excellent choice for seals and gaskets in cold environments, particularly in automotive fuel lines, hydraulic systems, and refrigeration applications.

NBR offers good low-temperature flexibility, making it ideal for seals in cold environments like automotive fuel systems and refrigeration.

Cons of NBR

1. Poor Ozone and UV Resistance³

NBR’s resistance to ozone, weather, and UV exposure is limited. Prolonged exposure to these environmental factors can lead to cracking and degradation of the material. Therefore, NBR is not suitable for outdoor applications where prolonged exposure to sunlight or harsh weather conditions is common.

NBR has poor resistance to ozone, UV rays, and weathering, making it unsuitable for outdoor applications with prolonged sun exposure.

2. Limited High-Temperature Performance

Although NBR performs well at low temperatures, its performance at high temperatures is limited. It typically operates effectively at temperatures up to 100°C, and in certain formulations, it may tolerate up to 120°C. However, it degrades more rapidly at higher temperatures, making it unsuitable for high-temperature applications.

NBR’s high-temperature resistance is limited, typically around 100°C, which can be a disadvantage in high-temperature environments.

Temperature Resistance of NBR

Property	Range
Low-Temperature	-40°C to -50°C
High-Temperature	Up to 100°C to 120°C

3. Poor Resistance to Ozone and Weathering

In addition to UV exposure, NBR also has limited resistance to ozone and weathering. The presence of ozone in the atmosphere can cause the rubber to crack, particularly if it’s not properly protected or treated. For this reason, NBR is generally not recommended for outdoor sealing applications unless it’s compounded for ozone resistance.

NBR has poor resistance to ozone and weathering, making it unsuitable for outdoor applications unless treated for better protection.

4. Not Suitable for Steam and Hot Water

NBR’s chemical and thermal properties make it unsuitable for use in steam and hot water applications. It degrades when exposed to steam or hot water, which can cause leaks and failure of seals. Materials like EPDM or FKM are better suited for such environments.

NBR is not suitable for steam or hot water applications due to its tendency to degrade under high-temperature conditions.

Applications of NBR

Despite its drawbacks, NBR remains a preferred material in several industries. Some of the most common applications include:

• Automotive: Seals, gaskets, fuel hoses, O-rings.
• Aerospace: Fuel systems, hydraulic systems.
• Oil & Gas: Seals and gaskets for pumps and valves.
• Food and Beverage: Seals in low-temperature applications (Note: ensure that the formulation is food-grade).

NBR is widely used in automotive, aerospace, and oil & gas industries for seals and gaskets, but it’s not suitable for steam or high-temperature applications.

Conclusion

NBR is a highly versatile material with excellent resistance to oils, fuels, and low temperatures. However, its performance is limited when it comes to ozone, UV resistance, and high-temperature environments. For applications requiring flexibility, low-temperature performance, and oil resistance, NBR is a strong choice. But for applications exposed to sunlight, ozone, or extreme heat, alternative materials like EPDM, Viton, or silicone might be better options.

Footnotes：