Good, Better, Best: Choosing the Right Elastomer Compound for Your Application

Remember the story of Goldilocks? Finding something that’s “just right” can be a challenge, whether it’s porridge, beds, or sealing compounds. Some materials might be too costly for your needs, while others might not offer the “just right” amount of durability. To help you strike the perfect balance, we’ve categorized sealing materials into “Good, Better, Best” groups by application. This way, you can easily identify which option is just right for your application, whether it’s a simple fix or a highly demanding job.

General Industrial

Good: Nitrile Rubber (NBR)

NBR is your go-to for general-purpose sealing. It’s versatile, affordable, and highly effective in handling oils and fuels. If cost is a significant concern and your application doesn’t involve harsh chemicals or extreme temperatures, NBR is often a solid choice.

Best For: General-purpose sealing where cost is a key factor and there’s exposure to oils and fuels.
Pros: Low cost, readily available, excellent oil resistance.
Cons: Poor ozone and sunlight resistance; lack of high-temperature tolerance and chemical resistance.

Better: EPDM Rubber

EPDM steps it up a notch with superior resistance to weathering, ozone, and aging. Ideal for outdoor applications, this material ensures longevity even in harsh environmental conditions.

Best For: Outdoor applications where resistance to weathering, ozone, and aging is essential.
Pros: Excellent ozone and sunlight resistance, steam resistance, NSF and FDA-compliant options.
Cons: Not suitable for oils, gasses, acids, and many solvents.

Best: Fluoroelastomer (FKM)

When the environment is exceptionally harsh, with high temperatures and exposure to chemicals, FKM is the premium choice. It’s built to withstand the toughest conditions and provide long-lasting performance.

Best For: Harsh environments with high temperatures and exposure to aggressive chemicals.
Pros: High-temperature resistance, acid and fuel resistance, excellent compression set resistance. Standard Viton is readily available.
Cons: More expensive than NBR or EPDM, limited resistance to steam and amines.

High-Temperature

Good: Silicone Rubber

Silicone rubber is a reliable choice for moderate high-temperature applications, with the ability to withstand temperatures up to 400°F. Its flexibility makes it an excellent option for situations where maintaining a seal at varying temperatures is critical. Additionally, its compatibility with food and beverage applications—thanks to FDA compliance in most silicones—adds to its versatility.

Best For: Moderate high-temperature applications where flexibility is key.
Pros: Good heat resistance, excellent resistance to oxygen and ozone, FDA compliance.
Cons: Not ideal for dynamic applications due to poor abrasion resistance and high gas permeability; limited resistance to solvents and oils.

Silicone is often a lower-cost material, making it a cost-effective solution for less demanding high-temperature applications. However, if your application involves frequent movement or exposure to aggressive chemicals, you might need to consider a higher-performing material.

Better: Fluoroelastomer (FKM)

When the environment is more challenging, FKM (trade name Viton) steps it up with its exceptional chemical resistance and higher temperature tolerance. This material is a popular choice in harsh environments, such as chemical plants and high-heat scenarios, where durability is paramount.

Best For: Harsh environments, including chemical plants and high-heat scenarios.
Pros: High-temperature resistance, excellent resistance to acids, fuels, and ozone, good compression set resistance, readily available.
Cons: More expensive than some other options; limited resistance to steam, hot water, and amines.

Viton is a go-to material when you need a robust, reliable seal in demanding conditions. While it comes with a higher price tag, its performance in challenging environments often justifies the investment.

Best: Perfluoroelastomer (FFKM)

For the most extreme high-temperature applications, perfluoroelastomer (FFKM) is the top-tier choice. Capable of withstanding temperatures up to 635°F, FFKM offers unparalleled chemical resistance, making it indispensable in industries like aerospace and extreme chemical processing.

Best For: The most demanding applications that deal with ultra-high temperature or extreme chemical processing.
Pros: Exceptional compression set resistance, superior chemical resistance, extreme high-temperature tolerance.
Cons: Significantly higher cost compared to standard commercial compounds.

FFKM provides peace of mind when performance is critical and conditions are extreme. Its higher cost is balanced by its ability to endure where other materials might fail.

Honorable Mention: Flexible Graphite

For applications where extreme temperatures, chemical exposure, and high pressure converge, flexible graphite deserves a nod. It’s not an elastomer but offers outstanding temperature and chemical resistance. We often only recommend flexible graphite when it is the only option, as it is not optimal for many day-to-day applications.

Chemical Resistance

Good: EPDM Rubber

EPDM rubber is a solid choice for applications requiring resistance to various chemicals, particularly in mild acidic and alkaline environments. It’s often used in water treatment and other scenarios where exposure to low-concentration chemicals is common. EPDM is valued for its balance of affordability and chemical resistance, making it a dependable option for less demanding applications.

Best For: Water treatment and low-concentration chemicals.
Pros: Cost-effective, good resistance to a variety of chemicals, excellent resistance to weathering and ozone.
Cons: Not suitable for oils, hydrocarbons, or concentrated chemicals.

If your application involves exposure to mild chemicals in moderate environments, EPDM provides a reliable and budget-friendly solution.

Better: Chloroprene (Neoprene) Rubber

Chloroprene, commonly known as neoprene, offers enhanced resistance to moderate chemicals and oils. It’s a step up from EPDM in terms of versatility, making it suitable for applications with a mix of chemical exposure and moderate temperature demands. Neoprene also performs well in environments where low-temperature flexibility and refrigerant resistance are important.

Best For: Applications with a mix of chemical exposure and moderate temperature needs.
Pros: Very cost-effective, decent low-temperature resistance, good refrigerant resistance, excellent aging and ozone resistance compared to nitrile.
Cons: Lacks high-temperature resistance; limited resistance to many solvents and stronger chemicals.

Neoprene is ideal for applications that require a balance between chemical resistance and cost-efficiency, especially where temperatures are not excessively high.

Better: Viton (FKM)

There are several options for applications that require chemical resistance, so we wanted to give a second “better” option a quick shout-out. Viton (FKM) is known for its exceptional chemical resistance, making it a preferred material in harsh environments, such as chemical plants and high-heat scenarios. It offers superior resistance to various chemicals, including acids, fuels, and ozone, along with high-temperature tolerance. This makes Viton a versatile and durable choice for demanding applications.

Best For: Harsh environments, including chemical plants and high-heat scenarios.
Pros: High-temperature resistance, acid resistance, fuel resistance, excellent ozone and compression set resistance, readily available.
Cons: More expensive than some other options, not ideal for steam, hot water, or amines.

Viton is the material of choice when both chemical resistance and high-temperature performance are required, though it comes at a higher cost.

Best: Perfluoroelastomer (FFKM)

For ultimate chemical resistance, perfluoroelastomer (FFKM) is unmatched. It is specifically designed to withstand the most aggressive chemicals across a wide temperature range, making it essential for industries dealing with highly corrosive substances, such as petrochemicals or refining. FFKM offers superior resistance to all known chemicals, ensuring long-term durability even in the harshest environments.

Best For: Industries dealing with highly corrosive chemicals, such as petrochemicals or refining.
Pros: Superior resistance to all known chemicals, excellent high-temperature performance, exceptional compression set resistance.
Cons: Higher cost compared to other elastomers.

When your application involves the harshest chemical exposures and demands the highest level of performance, FFKM is the top-tier choice, offering reliability where other materials might fall short.

Food and Beverage

Good: Nitrile Rubber (FDA Grade)

FDA-grade nitrile rubber is a cost-effective option for basic food processing seals. It complies with food safety standards, making it suitable for applications where budget is a primary concern without compromising on compliance. Nitrile is particularly effective in environments where food safety is paramount, but exposure to high temperatures or aggressive cleaning processes is limited.

Best For: Basic food processing seals where cost is a priority.
Pros: Cost-effective, FDA-compliant, metal-detectable compounds available.
Cons: Limited resistance to high temperatures and harsh cleaning chemicals.

Nitrile is a reliable choice for straightforward food processing tasks where affordability and compliance are key considerations.

Better: EPDM Rubber (FDA Grade)

For more demanding food processing environments, FDA-grade EPDM rubber offers improved resistance to heat and steam. This makes it suitable for regular exposure to high temperatures or steam cleaning applications. EPDM is widely available in FDA-compliant formulations, ensuring that it meets stringent food safety standards while providing enhanced durability under tougher conditions.

Best For: Applications with regular exposure to high temperatures or steam cleaning.
Pros: Readily available in FDA-compliant materials, excellent steam resistance, NSF- and FDA-compliant formulations.
Cons: No metal-detectable compounds are stocked, but they are available with slightly longer lead times.

EPDM is the better option when you need a seal that can withstand more rigorous processing environments, particularly those involving heat and steam.

Best: Silicone Rubber (FDA Grade)

When it comes to high-temperature food processing, particularly in industries like bakery and confectionery, FDA-grade silicone rubber is the top choice. Its flexibility and wide temperature range make it ideal for applications where both performance and food safety compliance are critical. Additionally, silicone’s availability in metal-detectable compounds adds an extra layer of safety, particularly in environments where product contamination must be avoided at all costs.

Best For: High-temperature food processing, particularly in bakery and confectionery industries.
Pros: Excellent flexibility, broad temperature range, FDA compliant, metal detectable compounds available.
Cons: Higher cost compared to nitrile and EPDM, not ideal for caustic applications.

Silicone is often the best option for food and beverage applications that demand superior performance under extreme conditions while ensuring compliance with food safety standards.

Honorable Mention: FKM

FKM (Viton) can also be considered for applications that require exceptional chemical resistance and food safety compliance. While not always the first choice due to cost, its durability in harsh environments makes it a viable option for specific food processing needs that require both chemical resistance and high performance.

Oil and Gas

Good: Hydrogenated Nitrile Rubber (HNBR)

Hydrogenated nitrile rubber (HNBR) is an enhanced version of standard nitrile. It offers improved heat and oil resistance, making it a solid choice for applications with common higher temperatures and oil exposure. HNBR is often used in environments where traditional nitrile would not suffice due to its superior performance in challenging conditions.

Best For: Applications with higher temperature demands and oil exposure.
Pros: Improved heat resistance compared to standard nitrile, excellent resistance to oils and fuels, good mechanical properties.
Cons: Less chemical resistance compared to higher-end materials like FKM and FFKM.

HNBR is a reliable and cost-effective choice for oil and gas applications that require better performance than standard Nitrile but don’t need the advanced properties of more expensive compounds.

Better: Viton (FKM)

Viton (FKM) is a go-to material in the oil and gas industry due to its exceptional chemical resistance, particularly against oils, fuels, and aggressive chemicals. It also offers high-temperature tolerance, making it suitable for more demanding environments. Viton is highly durable, which ensures long-lasting performance in challenging conditions.

Best For: Harsh environments, including those with exposure to chemicals, high temperatures, and oils.
Pros: High temperature resistance, excellent resistance to a wide range of chemicals including acids and fuels, good ozone and compression set resistance.
Cons: More expensive than HNBR, limited resistance to steam, hot water, and amines.

Viton is ideal for applications that require a higher level of chemical resistance and temperature tolerance, making it a better option for more demanding oil and gas environments.

Best: Perfluoroelastomer (FFKM)

Perfluoroelastomer (FFKM) is the top-tier choice for oil and gas applications that involve the most corrosive chemicals and extreme temperatures. FFKM provides unparalleled resistance to all known chemicals, including the most aggressive ones found in the petrochemical and refining industries. It is designed to perform in the most demanding conditions where other materials might fail.

Best For: Industries dealing with highly corrosive chemicals, such as petrochemicals or refining.
Pros: Superior resistance to all known chemicals, extreme high-temperature tolerance, excellent compression set resistance.
Cons: Higher cost compared to other elastomers.

For the most critical oil and gas applications, where failure is not an option, FFKM offers the ultimate in performance and durability. Its high cost is justified by its ability to endure the harshest conditions.

Choosing the Right Compound for Your Seal

Just like Goldilocks in her quest for the perfect porridge, finding the “just right” sealing compound is all about balance. You don’t always need the most expensive, high-end material to get the job done, but you also don’t want to settle for something that won’t stand up to the demands of your application. By understanding the strengths and limitations of each option, you can choose a compound that’s perfectly suited to your needs—whether that’s a cost-effective solution for a simple task or a premium material for extreme conditions.

At Marco Rubber, we believe in making your selection process as straightforward as possible. Our “Good, Better, Best” guide is here to help you make informed decisions, ensuring that your seals are reliable, durable, and exactly what your application requires.

If you’re still unsure about which material is your “just right,” don’t hesitate to reach out for personalized recommendations. And be sure to explore our chemical compatibility chart and other tools to help you find the perfect match for your sealing needs.

Because when it comes to sealing compounds, it’s not about choosing the most or least—it’s about finding what’s just right.