Elastomeric Closed Cell Foam Gasket Comparison: Neoprene, EPDM, Blended EPDM, Vinyl Nitrile, and ECH Foam

Whether you’re designing components for sealing, gasketing, vibration damping, or insulation, the foam material you use will directly impact your application’s longevity and performance. Different types of foam react differently depending on the application environment. It’s up to you to choose a foam that best meets the requirements of your specific application. Among the most used elastomeric closed-cell foams are Neoprene (CR), EPDM, Blended EPDM (EPDM/CR/SBR), Vinyl Nitrile (PVC/NBR), and ECH (Epichlorohydrin). Each of these types of materials provides specific benefits and they also carry some specific weaknesses. Depending on the specific needs, they’re not interchangeable. Each of these materials have distinctly different properties that make them suited for specific environments and functional requirements. 

We’re here to help you determine the most appropriate material for your gasketing or sealing needs. Find out more about these materials, their composition, and where they are best used in your industry. 

Neoprene Foam (CR)

Chemically known as polychloroprene, neoprene is a synthetic rubber known for its well-balanced performance. It has a versatile combination of mechanical strength, cushioning, and chemical resistance, making it suitable for a broad range of general-purpose applications. 

The Composition and Characteristics of Neoprene

Neoprene is rugged and has high tensile strength, tear resistance, and elongation, which means it stretches well under stress without breaking. The material also provides good compression set resistance, meaning it can return to its original shape after being compressed, making it ideal for sealing applications. 

While not exceptional in any one category, Neoprene performs well across many environments. It has a moderate resistance to oils, chemicals, ozone, and UV. Flame-retardant grades are also available to meet standards such as UL 94 and FMVSS 302, making it viable in environments where fire safety is a concern. 

Neoprene is often used in applications that include: 

  • HVAC system insulation 

  • Vibration dampening pads 

  • Marine and automotive gaskets 

  • General-purpose gasketing and sealing 

EPDM Foam (Ethylene Propylene Diene Monomer)

If your application involves long-term outdoor exposure, EPDM foam is very good place to start your search. Its resistance to many different environmental hazards is often unmatched among other common elastomeric foams. 

The Composition and Characteristics of EPDM Foam

EPDM is most widely known for its UV, ozone, and weather resistance. It’s also able to withstand broad temperature extremes, with some formulations performing reliably in environments as cold as -75°C (-103°F). EPDM’s chemical resistance to acids and water is also very high, making it particularly effective in sealing applications that are exposed to moisture, steam, or acidic vapors. 

However, EPDM performs poorly in environments that involve exposure to oils, fuels, or solvents. It also has lower inherent shock absorption compared to nitrile-based foams. 

The typical applications of EPDM foam include: 

  • Outdoor weatherstripping 

  • Cabinet and electrical enclosures 

  • Automotive door and window seals 

  • Rooftop HVAC and utility gaskets 

Blended EPDM Foam (EPDM/CR/SBR Blend)

Blended EPDM foams combine the strengths of multiple polymers—most notably EPDM, Neoprene (CR), and Styrene Butadiene Rubber (SBR). This results in a cost-effective, resilient, general-purpose sealing material that is highly flexible. 

The Composition and Characteristics of Blended EPDM Foam

Blended EPDM brings together EPDM foam’s weather resistance, neoprene’s elongation, and SBR’s cold-temperature flexibility. As a result, Blended EPDM foams have very good ozone resistance, excellent horizontal flame resistance, and solid mechanical durability. These foams also perform well in cold environments and have consistent compression recovery over time. Flame-retardant grades are also available to meet standards such as UL 94 and FMVSS 302, making it viable in environments where fire safety is a concern. 

On the downside, like pure EPDM, these blends offer low resistance to oils and fuels, making them less suitable for automotive or industrial oil-seal environments. 

Blended EPDM foams are often used in: 

  • HVAC gasketing 

  • Utility seals and enclosures 

  • General-purpose indoor and outdoor gaskets 

  • Electrical and electronic enclosures 

Vinyl Nitrile Foam (PVC/NBR Blend)

Vinyl Nitrile is a blend of polyvinyl chloride (PVC) and nitrile butadiene rubber (NBR). It’s an engineered foam that has a high chemical resistance, particularly to oils, fuels, and solvents. It also provides impressive shock absorption, compression recovery, and flame resistance (it has a particularly good resistance to vertical flame sources). 

The Composition and Characteristics of Nitrile Foam

Vinyl Nitrile is particularly useful in applications involving oil and fuel exposure, as it excels where EPDM and even Neoprene may fall short. It also performs well in thermal and acoustic insulation, especially in automotive and industrial machinery environments. If you need a foam with excellent shock absorption and compression set recovery, nitrile foam can give you the performance your application demands. 

While nitrile foam has many advantages, its UV and ozone resistance is poor, making it a less suitable option for outdoor applications unless protected or shielded. 

Where should you use this type of foam? Its common applications include: 

  • Oil-resistant gaskets for industrial machinery 

  • HVAC thermal and acoustic insulation 

  • Automotive interiors and under-hood components 

  • Protective padding and impact-resistant enclosures 

Closed Cel Epichlorohydrin (ECH) Foam

Closed cell ECH foam is a high-performance gasketing material known for its outstanding resistance to fuels, oils, and extreme temperatures. With excellent sealing capabilities and a stable cellular structure, ECH foam is ideal for demanding industrial and automotive applications where chemical exposure is a concern. 

The Composition and Characteristics of ECH Foam

Epichlorohydrin rubber is a synthetic elastomer engineered for harsh environments. It offers a unique combination of chemical resistance, low permeability, and thermal stability. ECH foam resists swelling or degradation in contact with fuels, hydraulic fluids, oils, and solvents. It also maintains flexibility in both high and low temperature extremes, with wide operating temperature ranges. 

ECH foam provides excellent compression set resistance and low gas permeability, making it effective for long-term sealing in tight-tolerance enclosures. It also demonstrates good UV, ozone, and weathering resistance, allowing for limited outdoor use. 

One drawback is that ECH foam tends to be more expensive than other closed cell materials, and it may be overengineered for general-purpose sealing applications where oil resistance is not required. 

ECH foam is often used in: 

  • Automotive fuel system gaskets and seals 

  • Industrial equipment exposed to oils and fuels 

  • HVAC systems requiring chemical-resistant insulation 

  • Seals in aerospace and high-performance machinery 

Comparing The Physical Properties of Foam Gasket and Seal Options

Each material offers a unique mix of strengths and trade-offs, making careful selection critical to performance and longevity in application-specific contexts. 

  • Neoprene: neoprene offers good all-around performance with fair resistance to UV and ozone, solid oil and fuel resistance, and decent shock absorption. Its compression set recovery and temperature tolerance are reliable, making it a popular general-purpose option.  

  • EPDM: EPDM is ideal for UV, ozone, and weather resistance, making it the top choice for outdoor applications. It also performs exceptionally well in low temperatures and maintains good compression set recovery, but it falls short when exposed to oils and fuels. 

  • Blended EPDM: blended EPDM strikes a balance between the neoprene and EPDM, offering good UV resistance and compression recovery, with improved flame resistance in horizontal burn scenarios. It also performs well in cold environments, although its oil resistance is limited.  

  • Vinyl Nitrile: vinyl nitrile mostly stands out for its excellent resistance to oils, fuels, and chemicals. It also offers top-tier shock absorption and compression recovery, making it ideal for high-impact or vibration-sensitive environments. However, its weaknesses lie in its poor weather, UV, and ozone resistance, which limits its suitability for outdoor use. 

  • ECH Foam: ECH foam is used for its exceptional resistance to fuels and oils, making it a strong choice for automotive, aerospace, and industrial applications where exposure to harsh chemicals and heat is common. It also offers good aging properties and retains flexibility across a wide temperature range. However, its biggest drawback is its relatively high cost compared to other foam materials. 

Environmental and Regulatory Considerations

Each foam type’s suitability for specific environments, especially those involving exposure to chemicals, UV, flame, or extreme temperatures. This is often dictated by its base polymer chemistry. A few good rules to live by: 

  • Neoprene balances resistance to oil, UV, and compression, but does not dominate in any one area. Choose Neoprene for versatile, general-purpose gasketing where balanced performance is important. 

  • EPDM is unmatched for outdoor and water-sealing use but must be avoided around hydrocarbons. Choose EPDM for outdoor exposure, UV stability, and water sealing. 

  • Blended EPDM fills the gap for cost-effective applications needing both weather and flame performance. Choose Blended EPDM when you need a hybrid solution with cost-efficiency and flame resistance. 

  • Vinyl Nitrile should be your go-to for high-performance oil resistance, best in class flame resistance, and impact damping, particularly in internal applications where UV is not a concern. Choose Vinyl Nitrile for environments involving oil, fuel, or heavy vibration. 

  • ECH should be used when your application’s environment is highly exposed to fuels, oils, and high or extremely low temperatures. This material will hold up in some of the most rugged environments. 

Compliance with UL 94, FMVSS 302, and other flame/chemical resistance standards also varies by material and grade. Custom formulations can be tailored to meet stringent regulatory requirements in the automotive, aerospace, and electronics industries. 

How to Make the Right Foam Decision

Each of these materials has been engineered to address specific challenges in sealing and protection. When generating your specification, leveraging ASTM D1056 to call out specific elastomeric foam properties helps ensure the proper material call out even as products and vendors change.  If you're unsure which is right for your application, partner with our experienced foam converters to make sure your material is not just sufficient, but optimal for your application. 

Matt Tempelis