Choosing the right rubber material is one of the most important decisions when designing a custom extruded component. The material you select can affect everything from temperature resistance and flexibility to durability, chemical compatibility, weather resistance, and the overall lifespan of the finished product.
There is no single rubber compound that is ideal for every application. A seal exposed to outdoor weather conditions has very different requirements from a gasket that regularly comes into contact with petroleum-based oils. Likewise, a component operating in extreme temperatures may require a completely different material than one used in a general industrial environment.
At Northwest Rubber Extruders (NWRE), we manufacture custom rubber extrusions for a wide range of applications and industries. Understanding the advantages and limitations of different elastomers is an important first step in determining which material is best suited for your project.
What Should You Consider When Selecting a Rubber Material?
Before choosing a rubber compound, it’s important to understand the environment in which the finished extrusion will operate.
Several factors should be considered, including:
- Operating temperature
- Exposure to sunlight and UV radiation
- Ozone and weather exposure
- Oils, fuels, solvents, and other chemicals
- Water and moisture
- Compression and recovery requirements
- Abrasion and physical wear
- Required flexibility
- Hardness or durometer
- Indoor versus outdoor use
- Regulatory or industry requirements
- Expected service life
The importance of each factor depends on the application.
For example, an exterior weather seal may require excellent resistance to UV exposure, ozone, moisture, and temperature changes. An industrial gasket used around machinery may instead require resistance to oils, fuels, or chemicals.
Understanding these conditions allows engineers and manufacturers to narrow down the available materials and select an elastomer with the appropriate performance characteristics.
EPDM Rubber
EPDM (ethylene propylene diene monomer) is one of the most commonly used materials for custom rubber extrusions.
One of EPDM’s greatest strengths is its resistance to environmental exposure. It performs well when exposed to sunlight, ozone, water, and changing weather conditions, making it particularly useful for exterior applications.
Common applications for EPDM extrusions include:
- Weatherstripping
- Window and door seals
- Construction seals
- Automotive components
- HVAC applications
- Outdoor equipment
- Industrial gaskets
- Water-resistant seals
EPDM also maintains good flexibility across a broad temperature range.
However, EPDM generally isn’t the best choice for applications involving petroleum-based oils and fuels. If oil resistance is a major requirement, another elastomer such as nitrile may be more appropriate.
When should you consider EPDM?
EPDM is often an excellent starting point when your extrusion needs to withstand weather, water, ozone, UV exposure, and outdoor environmental conditions.
Neoprene Rubber
Neoprene, also known as polychloroprene, is another versatile material frequently used for industrial rubber products.
One of the advantages of Neoprene is its balanced performance characteristics. It provides good resistance to weathering while also offering moderate resistance to oils, chemicals, abrasion, and physical wear.
This combination makes Neoprene useful when an application encounters several environmental factors rather than one extreme condition.
Common applications include:
- Industrial seals
- Gaskets
- Equipment components
- Construction applications
- Transportation components
- Protective rubber profiles
- Marine applications
Neoprene can be an effective choice when a product needs good overall durability and environmental resistance without requiring the specialized characteristics of another elastomer.
Nitrile Rubber (Buna-N)
Nitrile rubber, frequently referred to as Buna-N or NBR, is particularly well known for its resistance to petroleum-based oils and fuels.
This makes nitrile a common choice for applications involving machinery, automotive systems, fuel handling, and industrial equipment.
Common nitrile applications include:
- Oil-resistant seals
- Industrial gaskets
- Machinery components
- Automotive components
- Fuel-related applications
- Hydraulic and pneumatic equipment
Compared with materials such as EPDM, nitrile generally provides significantly better resistance to oils and petroleum products.
However, it typically does not provide the same level of long-term weather, ozone, and UV resistance as EPDM.
EPDM vs. Nitrile
One simple way to understand the difference is to look at the operating environment.
For outdoor weather and water exposure, EPDM is frequently the better option.
For oil and petroleum exposure, nitrile is often the stronger candidate.
The exact material should always be evaluated based on the application’s complete operating conditions.
SBR Rubber
SBR (styrene-butadiene rubber) is a general-purpose synthetic rubber used in a wide variety of industrial applications.
It offers good abrasion resistance and mechanical properties while remaining a cost-effective material for applications that don’t require specialized resistance to extreme environmental conditions or chemicals.
SBR may be used for:
- General-purpose seals
- Industrial components
- Gaskets
- Protective profiles
- Rubber strips
- Abrasion-resistant applications
SBR can be a practical solution when durability and cost effectiveness are important and the product won’t face demanding exposure to ozone, weather, petroleum products, or extreme temperatures.
Silicone Rubber
Silicone is particularly valuable for applications involving temperature extremes and environments where material stability is critical.
Silicone rubber can maintain flexibility across a wide temperature range and offers excellent resistance to ozone, UV radiation, and environmental aging.
These characteristics make custom silicone extrusions suitable for demanding applications across a variety of industries.
Typical applications may include:
- High-temperature seals
- Medical equipment
- Food-processing equipment
- Aerospace components
- Electronics
- Lighting systems
- Industrial machinery
- Transportation applications
- Specialized environmental seals
Silicone is also available in numerous configurations, colors, hardness levels, and formulations.
For projects where extreme temperature performance or long-term environmental stability is important, silicone is often one of the first materials engineers consider.
Other Elastomers and Flexible Materials
EPDM, Neoprene, nitrile, SBR, and silicone represent only some of the materials available for custom extrusion applications.
Depending on the project, other elastomers and flexible thermoplastic materials may provide more appropriate performance characteristics.
Material selection should therefore be based on the complete requirements of the component rather than simply choosing the most commonly used rubber compound.
NWRE works with customers to evaluate materials and manufacturing requirements for custom extrusion projects. Our Material & Engineering resources can also help engineers and purchasing teams evaluate options during product development.
How Does Durometer Affect a Rubber Extrusion?
Selecting the rubber compound itself is only part of the process.
Another important consideration is durometer, which measures the hardness of a rubber material.
A softer rubber compound can compress more easily, which may be desirable for certain seals and gaskets. A harder compound may provide greater rigidity and resistance to deformation.
The appropriate durometer depends on factors such as:
- Required sealing pressure
- Compression
- Component geometry
- Installation method
- Mechanical stress
- Flexibility requirements
Two extrusions made from the same general type of rubber can perform very differently depending on their formulation and durometer.
This is why material selection and profile design should be considered together rather than independently.
Consider the Entire Operating Environment
A common mistake when selecting a rubber material is focusing on only one performance requirement.
For example, knowing that a component needs to withstand 200°F doesn’t provide enough information to select the best material.
You may also need to know:
- Is the component outdoors?
- Will it encounter oil?
- Is it continuously compressed?
- Will it be exposed to ozone?
- Does it encounter cleaning chemicals?
- How often will it flex?
- Does it need to resist abrasion?
- What is the minimum operating temperature?
- What is the expected service life?
The answers can significantly change the recommended material.
This becomes particularly important when designing components for specialized markets. NWRE supplies custom extruded and molded products for a wide variety of industries and applications, each of which can present different environmental and performance requirements.
Don’t Overlook the Extrusion Profile
Material selection is important, but the design of the extrusion itself also has a major impact on performance.
Custom rubber extrusions can be manufactured in numerous profiles and configurations, including:
- Solid profiles
- Hollow profiles
- Tubing
- Channels
- D-shaped profiles
- P-shaped profiles
- Seals
- Gaskets
- Bumpers
- Custom geometric profiles
Wall thickness, profile geometry, tolerances, compression requirements, and installation method should all be evaluated during the design process.
A properly selected rubber compound combined with a well-designed extrusion profile can improve sealing performance, simplify installation, and extend the component’s service life.
Prototype and Test When Necessary
For demanding applications, material selection shouldn’t rely entirely on published material properties.
Actual operating conditions can involve combinations of temperature, chemicals, compression, vibration, environmental exposure, and mechanical stress.
Testing prototypes or production samples under realistic operating conditions can help confirm that the selected material and profile will perform as expected.
This can be particularly important for aerospace, transportation, industrial, medical, construction, and other applications where component performance is critical.
Which Rubber Material Is Right for Your Application?
There isn’t a universal answer.
As a general starting point:
EPDM is commonly considered for weather, water, ozone, and outdoor applications.
Neoprene provides balanced weather, abrasion, and moderate oil resistance.
Nitrile (Buna-N) is frequently selected when resistance to petroleum-based oils and fuels is important.
SBR can provide an economical solution for general-purpose applications requiring good abrasion resistance.
Silicone is often selected for extreme temperatures, environmental stability, and specialized applications.
The final decision should take into account the complete operating environment, physical requirements, product geometry, expected service life, and manufacturing process.
Work With an Experienced Custom Rubber Extrusion Manufacturer
Choosing the correct material early in the design process can help prevent premature component failure, unnecessary costs, and manufacturing complications later.
NWRE has extensive experience manufacturing custom rubber, silicone, and flexible plastic extrusions for customers across a broad range of industries. Our team can work from customer drawings and specifications to help manufacture profiles that meet the requirements of the finished application.
Whether you are developing a new component, replacing an existing extrusion, or evaluating alternative materials, understanding the operating environment is the first step toward selecting the appropriate solution.
Explore our Rubber Extrusions, Silicone Extrusions, Material & Engineering, and Industries Served resources to learn more.
Ready to discuss a custom extrusion project? Request a Quote from Northwest Rubber Extruders.