Epichlorohydrin rubber vs. silicone rubber for O-ring - What is The Difference?

Epichlorohydrin rubber offers superior oil and fuel resistance with excellent flexibility in low temperatures, making it ideal for automotive O-rings. Silicone rubber provides outstanding high-temperature stability and superior weathering resistance, preferred for aerospace and food-grade O-ring applications.

Table of Comparison

Introduction to O-Ring Materials

Epichlorohydrin rubber offers excellent resistance to ozone, heat, and weathering, making it ideal for automotive and refrigeration O-rings exposed to oil and fuel environments. Silicone rubber provides superior elasticity, chemical stability, and temperature resistance, suitable for medical devices, food processing, and aerospace O-rings requiring flexibility at extreme temperatures. Both materials address specific sealing needs, with Epichlorohydrin favored for hydraulic applications and Silicone preferred in hygiene-sensitive and high-temperature scenarios.

Overview of Epichlorohydrin Rubber

Epichlorohydrin rubber, known for its excellent resistance to oil, ozone, and weathering, is widely used in O-ring applications requiring durable sealing under harsh conditions. This synthetic elastomer exhibits superior low-temperature flexibility compared to Silicone rubber, making it ideal for automotive and industrial seals exposed to fuels and lubricants. Its moderate chemical resistance and good tensile strength provide a reliable alternative to Silicone rubber in environments demanding both heat and oil resistance.

Overview of Silicone Rubber

Silicone rubber O-rings offer exceptional temperature resistance, maintaining flexibility and sealing performance from -60degC to 230degC, which surpasses epichlorohydrin rubber's operational range. Their excellent chemical inertness and stability under UV and ozone exposure make silicone O-rings ideal for harsh environmental applications. Silicone also exhibits low compression set and excellent electrical insulation properties, enhancing reliability in automotive, aerospace, and medical sealing solutions.

Chemical Resistance Comparison

Epichlorohydrin rubber offers strong resistance to ozone, weathering, and moderate acids, making it suitable for applications involving exposure to oils, fuels, and alkalis. Silicone rubber excels in high-temperature stability and superior resistance to water, steam, and many chemicals but tends to degrade when exposed to strong acids and oils. Selecting between Epichlorohydrin and Silicone O-rings depends on the specific chemical environment, with Epichlorohydrin preferred for oil and alkali exposure and Silicone favored for extreme temperatures and water-based chemicals.

Temperature Range and Thermal Stability

Epichlorohydrin rubber O-rings typically operate within a temperature range of -40degC to 120degC, offering moderate thermal stability suitable for automotive and refrigeration applications. Silicone rubber O-rings provide superior temperature resistance, functioning effectively from -60degC to 230degC, making them ideal for high-temperature environments and applications requiring excellent thermal stability. Silicone's exceptional ability to maintain elasticity and sealing performance at elevated temperatures surpasses Epichlorohydrin rubber, which degrades faster under prolonged heat exposure.

Mechanical and Physical Properties

Epichlorohydrin rubber (ECO) offers excellent resistance to oils, fuels, and ozone with moderate mechanical strength, exhibiting tensile strength of approximately 7-12 MPa and elongation at break around 300%. Silicone rubber demonstrates superior flexibility and low-temperature performance with tensile strength typically between 6-10 MPa and elongation up to 700%, making it ideal for applications requiring extended temperature range from -60degC to 230degC. While Epichlorohydrin excels in chemical resistance and compression set stability, Silicone rubber provides outstanding thermal stability and excellent aging properties with lower mechanical abrasion resistance.

Aging and Environmental Performance

Epichlorohydrin rubber O-rings exhibit excellent resistance to ozone, weathering, and heat aging, maintaining flexibility and sealing integrity in temperatures ranging from -40degC to 120degC, making them suitable for automotive and fuel system applications. Silicone rubber O-rings offer superior aging resistance with stable performance across an extensive temperature range of -60degC to 230degC, excelling in UV, ozone, and steam exposure, ideal for medical, food, and aerospace industries. Environmental performance varies significantly, with epichlorohydrin rubber showing limited resistance to hydrocarbons and solvents compared to silicone rubber, which withstands harsh chemical environments but has lower mechanical strength and abrasion resistance.

Cost and Availability Considerations

Epichlorohydrin rubber O-rings offer a cost-effective solution with moderate availability, making them suitable for applications requiring oil and fuel resistance at a lower price point. Silicone rubber O-rings, while generally more expensive, provide superior flexibility and temperature resistance but may have limited availability in certain industrial grades. Budget-conscious projects benefit from epichlorohydrin due to lower material costs and widespread supply, whereas silicone suits high-performance needs despite higher expenses.

Typical Applications in Industry

Epichlorohydrin rubber O-rings excel in fuel handling, automotive, and refrigeration industries due to their superior oil, fuel, and chemical resistance, along with excellent low-temperature flexibility. Silicone rubber O-rings are widely used in food processing, medical devices, and aerospace applications, favored for their high-temperature stability, biocompatibility, and resistance to ozone and UV exposure. Choosing between these materials depends on the specific industrial environment and the chemical and thermal demands placed on the O-ring.

Selecting the Right Material for Your O-Ring

Epichlorohydrin rubber offers excellent resistance to ozone, oils, and weathering, making it ideal for fuel systems and hydraulic applications, while Silicone rubber excels in extreme temperature ranges from -60degC to 230degC with outstanding flexibility and chemical stability. Selecting the right material depends on the operating environment: Epichlorohydrin is preferred for applications requiring superior fuel resistance and moderate temperature stability, whereas Silicone is suitable for seals exposed to high thermal extremes and general-purpose sealing in food and medical industries. Consider factors such as chemical compatibility, temperature tolerance, and mechanical stress to ensure optimal O-ring performance and longevity.