Two types of rubber widely used for commercial applications are EPDM (Ethylene Propylene Diene Monomer) and silicone rubber. Material selection requires full comprehension of the differences between EPDM and silicone since they qualify as distinct choices for unique applications. This blog will provide a comprehensive comparison of silicone rubber and EPDM, helping you make an informed decision and communicate effectively with suppliers to choose the best material for your product.
What is EPDM?
The synthetic rubber EPDM consists primarily of three basic monomers including ethylene, propylene and diene. The material demonstrates superior resistance to outdoor elements such as UV rays as well as ozone exposure while enduring weathering conditions because of which it shows outstanding suitability for external use. The temperature resistance of EPDM extends across a wide range with acceptable flexibility between -70°C and higher temperatures which benefits its suitability in cold regions. The durable rubber material maintains its operational lifespan at 50 years when used outside in elements.
EPDM rubber stands out in industrial applications thanks to its broad application potential and enduring properties especially when added UV protection and weather-tight features are necessary to the design.
What is Silicone Rubber?
Silicone rubber exists as an inorganic polymer which consists of silicon together with carbon hydrogen and oxygen. Silicone shows its strongest advantage through its extraordinary tolerance of temperature ranges from -100°C to 270°C. Silicone performs exceptionally well under high heat conditions therefore it finds applications specifically in aerospace and automotive sectors. The excellent chemical stability of silicone provides protection from water and UV light and oxygen which increases its reliability in demanding environments during its extended operational life.
The biocompatible nature of silicone makes it suitable for medical and food industry applications because it presents no toxic hazards.
What are the Similarities Between EPDM and Silicone?
EPDM and silicone rubber are both compressible and elastic materials that can be molded and compressed to form seals, gaskets, and other components. They share a variety of features, such as:
- Elasticity and Compressibility: Both are compressible and possess good compression set, i.e., they are able to return to their original shape after compression.
- UV and Weather Resistance: Both EPDM and silicone provide weather resistance and resistance to UV radiation, making them suitable for applications that are to be used outdoors.
- Versatility in Sealing: EPDM and silicone both find wide use in sealing due to their environmental resistance and long life.
Although they share a few similarities, the fundamental differences in temperature resistance, chemical stability, and resistance to tough environments make them more suitable for some applications.
Silicone vs EPDM: Several Comparison
Temperature Resistance
EPDM is temperature rated between -70°C to 190°C, which is sufficient for the majority of use temperatures. It performs fairly well in cold conditions but poorly against heat. Silicone rubber performs extremely well in warm conditions, ranging from -100°C to 270°C. This makes silicone the ideal rubber to use where there is extensive heat or cold.
UV and Aging Resistance
EPDM is unique due to its resistance to weathering, ozone, and UV rays, so it’s commonly used in automotive and outdoor uses. Silicon also has good resistance to UV light as well as to oxygen but excels in warm and humid temperatures. Silicon is more stable over a wider temperature range and where UV exposure is extreme.
Chemical Resistance
EPDM is resistant to water, acid, and alkali but is bad with oils, fuels, and solvents. Silicone is more resistant to chemicals overall, although it might struggle with certain acids and alkalis. Silicone is also good for applications where there is a requirement for resistance to moisture and low/high temperatures.
Tear and Abrasion Resistance
EPDM is tougher and more abrasion- and tear-resistant than silicone, and therefore a better choice for applications involving a lot of friction or physical stress. Silicone, being softer and more flexible, has excellent compression set, that is, it can withstand long-term compression without distortion.
Silicone vs EPDM: Price
EPDM is generally cheaper, and this makes it the first choice material for applications not requiring extreme chemical or temperature resistance. Its lower initial cost of investment renders it the optimum option for large-scale or cost-constrained projects. Conversely, silicone is more expensive due to its superior traits, such as high-temperature stability and chemical inertness. While silicone is more expensive upfront, its increased lifespan and higher durability under harsh conditions can translate to fewer maintenance and replacement costs in the long term.
How Heat Affects Silicone vs EPDM
EPDM’s performance can deteriorate with prolonged exposure to high heat, leading it to shrink and lose its elasticity. But silicone rubber maintains its shape even in heat-intensive environments, which is why it is a popular material in industries like aerospace and electronics where heat resistance is the primary concern.
Long-term heat-aging tests demonstrate that EPDM shrinks to a great extent when exposed to temperatures above 100°C, while silicone is stable and remains in its initial shape and qualities, thanks to its Silicone Melting Point, which ensures its performance even under extreme heat conditions.
Application: Where will you find EPDM and Silicone
Silicone and EPDM both have a broad range of applications, though each material excels in different areas due to its unique properties.
Common Applications for Silicone and EPDM
Both silicone and EPDM are commonly used in the automotive industry, where their ability to handle high heat, resist harsh weather conditions, ultraviolet rays, and ozone makes them ideal for seals, gaskets, and hoses. These properties help ensure reliable performance in the demanding automotive environment.
In the building and construction industry, both materials are frequently used for door and window seals, gaskets, O-rings, and hoses. Their excellent elasticity, flexibility, and durability allow them to provide long-lasting protection in construction, ensuring that components remain sealed against the elements over time.
Both silicone and EPDM are also valued in the electronics industry for their insulating properties. They are commonly used in gaskets and electrical insulators for power delivery cables, helping protect sensitive electronics from environmental factors such as moisture, dust, and vibration.
Exclusive Applications for Silicone
While both materials share some common applications, certain industries benefit from the unique advantages of silicone. Silicone is particularly essential in aerospace, where its high tensile strength and resistance to extreme temperatures make it indispensable for critical components like circuit terminal coatings, engine parts, thermal protection, sensors, adhesives, and fuel tank coatings.
Additionally, silicone plays a vital role in the food and beverage industry, where its resistance to high temperatures and most chemicals ensures safe storage and handling of food products. This makes silicone ideal for kitchen equipment and medical devices, where non-toxic, high-performance materials are required.
Exclusive Applications for EPDM
On the other hand, EPDM is especially effective in the HVAC industry, where its low electrical conductivity, vibration resistance, and ability to accommodate thermal expansion make it a key component in grommets, drain tubes, and gaskets.
EPDM is also widely used in consumer appliances, where it reduces noise and vibration in machines like washing machines, refrigerators, and generators. Its ability to absorb vibrations helps improve the overall performance and longevity of household appliances.
Alternative Materials to Silicone and EPDM
While EPDM and silicone work well, there are other elastomers that may be suitable for specific applications. For example:
- Natural Rubber (NR): Offers superior tensile strength and abrasion resistance but lacks UV resistance.
- Chloroprene Rubber (CR): High resistance to oil, fuel, and solvents and so well suited to industry use but not to the high-temperature properties of silicone.
- Fluorocarbon Rubber (FKM): Good chemical and high-temperature properties but also more expensive than EPDM or silicone and only for superior applications.
Choosing the Right Material
When deciding between EPDM and silicone, look at temperature requirements, chemical exposure, and mechanical stress.
To make the best choice, evaluate the specific needs of your application:
- Temperature range
- Chemical exposure
- Mechanical properties (e.g., tear and abrasion resistance)
- Budget constraints
If you are not sure what rubber material would be best suited for your application, contact our experts now. We can help you figure out the appropriate material—be it EPDM, silicone, or otherwise—depending on your requirements and product specifications. Allow us to provide custom solutions so that you select the most logical material for your project.
With Lanxin‘s strong producing capability in Plastic Injection Molding, LSR Injection Molding, Silicone Compression Molding, Co-Injection Molding, and Over & Insert Molding, and our meticulous process from material selection to mold manufacturing, we can turn your product designs into a reality.
