EPDM vs. HNBR

Attribute	EPDM	HNBR
Chemical Resistance	Excellent	Excellent
Temperature Range	-50°C to 150°C	-40°C to 160°C
Compression Set	Good	Excellent
Tensile Strength	Good	Excellent
Cost	Lower	Higher

Introduction

EPDM (ethylene propylene diene monomer) and HNBR (hydrogenated nitrile butadiene rubber) are two popular elastomers used in various industries for their unique properties and applications. Both materials have their own strengths and weaknesses, making them suitable for different purposes. In this article, we will compare the attributes of EPDM and HNBR to help you understand which material may be more suitable for your specific needs.

Chemical Composition

EPDM is a synthetic rubber made from ethylene, propylene, and a diene monomer. This composition gives EPDM excellent resistance to weathering, ozone, and UV exposure, making it ideal for outdoor applications. On the other hand, HNBR is a hydrogenated version of nitrile butadiene rubber, which provides improved heat and chemical resistance compared to standard NBR. HNBR is known for its excellent resistance to oil, fuel, and other harsh chemicals, making it a popular choice for automotive and industrial applications.

Temperature Resistance

EPDM has a temperature range of -50°C to 150°C, making it suitable for a wide range of temperature conditions. Its excellent heat resistance allows EPDM to withstand high temperatures without losing its physical properties. HNBR, on the other hand, has a higher temperature range of -30°C to 150°C, making it more suitable for applications where higher temperatures are involved. HNBR's heat resistance makes it a preferred choice for automotive seals, gaskets, and hoses that are exposed to engine heat.

Compression Set

EPDM has a low compression set, which means it can maintain its shape and sealing properties even after being compressed for an extended period. This makes EPDM ideal for sealing applications where long-term compression is required. HNBR also has a low compression set, making it suitable for applications where a tight seal is essential. Both EPDM and HNBR are known for their resilience and ability to maintain their shape under pressure, making them reliable choices for sealing solutions.

Chemical Resistance

EPDM has good resistance to water, steam, and polar solvents, but it may not be suitable for applications involving oil and fuel exposure. HNBR, on the other hand, has excellent resistance to oil, fuel, and other hydrocarbons, making it a preferred choice for applications in the automotive and oil industry. HNBR's superior chemical resistance makes it a reliable material for seals, gaskets, and hoses that come into contact with harsh chemicals on a regular basis.

Weathering and Ozone Resistance

EPDM is known for its excellent weathering and ozone resistance, making it a popular choice for outdoor applications. Its ability to withstand UV exposure and extreme weather conditions makes EPDM ideal for roofing, window seals, and outdoor gaskets. HNBR also has good weathering and ozone resistance, but it may not be as effective as EPDM in prolonged outdoor exposure. HNBR is more commonly used in automotive and industrial applications where weathering is not a primary concern.

Cost and Availability

EPDM is a cost-effective material that is widely available in the market, making it a popular choice for a variety of applications. Its affordability and availability make EPDM a preferred material for sealing solutions in industries such as construction, automotive, and HVAC. HNBR, on the other hand, is a more specialized material that may be slightly more expensive than EPDM. However, HNBR's unique properties and superior performance in harsh environments justify its higher cost for specific applications.

Conclusion

In conclusion, both EPDM and HNBR have their own unique attributes that make them suitable for different applications. EPDM is known for its excellent weathering resistance and low cost, making it a popular choice for outdoor and general sealing applications. On the other hand, HNBR offers superior chemical resistance and heat resistance, making it a preferred choice for automotive and industrial applications where exposure to harsh chemicals and high temperatures is common. Ultimately, the choice between EPDM and HNBR will depend on the specific requirements of your application and the properties that are most important for your sealing solution.