azmater.com Silicone rubber offers superior temperature resistance and flexibility compared to Ethylene Propylene Diene Monomer (EPDM) rubber, which excels in chemical and weather resistance for O-ring applications. EPDM is preferred for outdoor and automotive environments, while silicone is ideal for high-temperature and food-grade sealing solutions.
Table of Comparison
| Property | Silicone Rubber (SiR) | Ethylene Propylene Diene Monomer (EPDM) |
|---|---|---|
| Temperature Range | -60degC to 230degC | -50degC to 150degC |
| Chemical Resistance | Resistant to ozone, oxygen, and UV; poor resistance to oils and fuels | Excellent resistance to water, steam, alkalis, and acids; poor resistance to oils and hydrocarbons |
| Elasticity & Flexibility | High flexibility, even at low temperatures | Good elasticity but less flexible than silicone |
| Compression Set | Moderate compression set resistance | Excellent compression set resistance |
| Applications | Food, medical, and high-temperature sealing | Automotive, HVAC, and weather sealing |
| Cost | Higher cost | More cost-effective |
Overview of Silicone Rubber and EPDM Rubber
Silicone rubber is prized for its excellent thermal stability, flexibility at low temperatures, and resistance to ozone, UV radiation, and aging, making it ideal for O-rings in extreme temperature environments. Ethylene propylene diene monomer (EPDM) rubber offers superior resistance to weathering, steam, water, and polar solvents, providing outstanding durability in automotive and industrial sealing applications. Both materials excel in different conditions: silicone rubber in high-temperature and low-temperature sealing, while EPDM is preferred for resistance to heat, chemicals, and environmental factors.
Key Properties of Silicone Rubber
Silicone rubber offers exceptional thermal stability, maintaining flexibility and elasticity across a wide temperature range from -60degC to 230degC, which makes it ideal for O-ring applications in extreme environments. It also exhibits excellent chemical resistance against water, ozone, UV, and many solvents, ensuring durability and a long service life. Compared to Ethylene Propylene Diene Monomer (EPDM) rubber, silicone provides superior weathering resistance and electrical insulation properties, though EPDM may offer better resistance to fuels and oils.
Key Properties of EPDM Rubber
EPDM rubber excels in O-ring applications due to its outstanding resistance to heat, ozone, and weathering, with operating temperatures typically ranging from -40degC to 150degC. Its exceptional elasticity and excellent resistance to water, steam, and polar chemicals make it ideal for sealing in automotive, HVAC, and plumbing systems. Unlike silicone rubber, EPDM offers superior chemical resistance against acids, alkalis, and ketones, enhancing durability in harsh environments.
Temperature Resistance Comparison
Silicone rubber offers superior temperature resistance for O-rings, maintaining flexibility and sealing performance between -60degC and 230degC, making it ideal for extreme heat or cold applications. Ethylene propylene diene monomer (EPDM) rubber performs well in moderate temperature ranges, typically from -40degC up to 150degC, but may degrade more quickly under prolonged high heat. For applications requiring wide temperature tolerance and stability, silicone rubber O-rings provide a more reliable solution compared to EPDM.
Chemical and Weather Resistance
Silicone rubber exhibits superior chemical resistance to oils, solvents, and extreme temperatures, maintaining flexibility from -60degC to 230degC, making it ideal for O-rings exposed to harsh chemical environments and wide temperature ranges. Ethylene propylene diene monomer (EPDM) rubber offers outstanding resistance to weathering, ozone, and steam, excelling in outdoor applications and exposure to water-based chemicals but demonstrates limited resistance to petroleum-based fluids. Selecting silicone rubber O-rings ensures enhanced performance in aggressive chemical and thermal conditions, while EPDM O-rings are preferred for weather-resistant and steam-exposed sealing solutions.
Compression Set and Elasticity
Silicone rubber O-rings exhibit superior elasticity with excellent flexibility at low temperatures, maintaining performance across a wide temperature range but tend to have higher compression set values compared to Ethylene Propylene Diene Monomer (EPDM) rubber. EPDM O-rings demonstrate lower compression set, offering better long-term seal integrity under static sealing conditions, especially in high heat and ozone exposure environments. While silicone excels in flexibility and temperature versatility, EPDM outperforms in maintaining dimensional stability and resilience against permanent deformation.
Suitability for Different Applications
Silicone rubber offers excellent high-temperature resistance up to 230degC and superior flexibility at low temperatures, making it ideal for food, medical, and aerospace O-rings requiring sterile, non-reactive seals. Ethylene propylene diene monomer (EPDM) rubber provides superior resistance to weathering, ozone, and chemicals such as acids and alkalis, making it suitable for automotive cooling systems, outdoor, and industrial sealing applications. The choice depends on the operating environment; silicone excels in thermal and electrical insulation while EPDM performs well in harsh chemical and environmental conditions.
Cost and Availability of O-Ring Materials
Silicone rubber O-rings typically have higher material costs due to their superior temperature and chemical resistance, making them ideal for specialized applications. Ethylene propylene diene monomer (EPDM) rubber offers a more cost-effective solution with widespread availability, especially for applications involving water, steam, and weather exposure. The broader market availability of EPDM O-rings often results in shorter lead times and reduced overall procurement expenses compared to silicone options.
Industry Standards and Certifications
Silicone rubber O-rings conform to industry standards such as ASTM D2000 and FDA 21 CFR 177.2600, offering excellent high-temperature resistance and biocompatibility for food and medical applications. Ethylene Propylene Diene Monomer (EPDM) rubber O-rings meet ASTM D1418 and ISO 3302 standards, providing superior resistance to weathering, ozone, and steam, and certifications like NSF for potable water systems.
Selecting the Right O-Ring Material for Your Needs
Silicone rubber offers superior temperature resistance, flexibility, and excellent sealing performance in extreme heat or cold, making it ideal for applications requiring durability in harsh environments. Ethylene propylene diene monomer (EPDM) rubber excels in resistance to weathering, ozone, water, and steam, making it well-suited for outdoor, automotive, and HVAC sealing applications. Selecting the right O-ring material depends on factors like temperature range, chemical compatibility, and environmental exposure to ensure optimal sealing reliability and longevity.
Infographic: Silicone rubber vs Ethylene propylene diene monomer rubber for O-ring