Silicone vs EPDM: which one should you choose for your application?
Two materials can fulfil the same function on a drawing and deliver very different results once the part enters service. When comparing silicone vs EPDM, the answer always depends on the actual working conditions.
EPDM vs Silicone: Key Differences
When comparing EPDM vs silicone, it is important to analyse factors such as operating temperature, chemical resistance, environmental exposure or the requirements of the industry in which the part will be used.
Two Materials for Different Requirements
Although both materials are commonly used in sealing, insulation or protection applications, their performance can vary considerably depending on the working conditions.
EPDM and silicone are two widely used elastomers in the manufacture of technical parts. They share properties such as elasticity and resistance to ageing, but present important differences in aspects such as operating temperature, chemical resistance or compatibility with certain environments.
These differences can be decisive when the part operates in contact with hot water, chemical agents, humidity or under specific regulatory requirements.
Operating Temperature: One of the Most Important Differences
Temperature is usually one of the factors that has the greatest influence when deciding between silicone and EPDM. Each material responds differently when continuously exposed to demanding thermal conditions.
When to Choose Silicone
Silicone stands out particularly for its performance at extreme temperatures. It can maintain its properties over long periods when operating at elevated temperatures and retain its elasticity even under extremely cold conditions. This characteristic explains its use in components subjected to significant temperature variations or where dimensional stability is particularly important.
As a reference, typical silicone temperature ranges are approximately -50°C to 200°C, and can reach up to 300°C with specific additives.
It also offers excellent resistance to ageing, ozone and ultraviolet radiation.
When to Choose EPDM
EPDM offers very good resistance to ageing, oxidation and exposure to weathering, ozone and UV radiation.
It also provides very good resistance to hot water and steam, making it a common choice for applications where these factors are continuously present.
When operating temperatures are moderate (typically ranging from -40°C to 120°C) and there are requirements related to environmental or chemical resistance, EPDM is often a highly competitive alternative.
Chemical Resistance and Environmental Performance
Chemical resistance is another key aspect when comparing silicone vs EPDM. Compatibility with substances present in the working environment can affect the service life of the part.
EPDM Chemical Resistance
EPDM offers very good resistance to many polar media, alkalis, acids and numerous non-hydrocarbon chemical compounds.
It also performs very well against moisture, hot water and prolonged exposure to weathering.
On the other hand, it is generally not the best choice when the part will come into contact with petrol, oils, greases or hydrocarbon-based solvents.
Silicone Stability and Durability
Silicone maintains stable performance in environments where significant temperature variations and prolonged exposure to environmental factors are present.
It is also physiologically inert when correctly formulated and certified, which has contributed to its use in sectors with specific requirements related to health or human contact (food-grade, medical or drinking-water contact certification).
Its resistance to ageing, ozone and ultraviolet radiation also contributes to maintaining its properties over long periods of use.
Cost and Performance
Cost is part of any material selection process, although it should rarely be the only deciding factor.
Balancing Performance and Budget
In general terms, EPDM is usually a more economical alternative to silicone. When working conditions allow either material to be used, EPDM can provide a highly efficient solution from an economic perspective.
Silicone, on the other hand, offers advantages related to temperature, stability and certain technical or healthcare applications that may justify a higher investment.
Which Material Should You Choose for Your Application?
The choice between EPDM and silicone always depends on the part’s operating conditions. Analysing the part’s requirements makes it possible to determine more precisely which material can provide the best performance.
Typical Recommendations by Industry
In automotive applications, the choice will mainly depend on the location of the part and the conditions to which it will be exposed. Temperature, chemical agents present and mechanical requirements are often determining factors.
In applications related to food, healthcare equipment or certain electrical components, silicone is often a common choice thanks to its thermal stability and the characteristics it offers when the formulation is intended for these types of environments.
In general industrial applications, EPDM is frequently used when resistance to ageing, hot water, weathering or certain chemical products is required.
| Application | Why EPDM Is a Good Fit |
|---|---|
| Gaskets for hot-water circuits | Good resistance to hot water, moisture and ageing. |
| EPDM cable glands for electrical cabinets or vehicle bodies | Provides sealing, protection against moisture and good ageing resistance in indoor or outdoor applications. |
| Stops, supports or cushioning components | Suitable for absorbing minor impacts, vibrations or repeated contact, provided there is no exposure to oils or hydrocarbons. |
| Sealing parts for outdoor industrial installations | A good option for environments exposed to moisture, oxidation, ageing and variable environmental conditions. |
| Application | Why Silicone Is a Good Fit |
|---|---|
| Parts for ovens, stoves or thermal equipment | Very good performance at elevated temperatures and under thermal cycling. |
| Parts for the food industry with certified grades | Can be formulated for food contact and offers good thermal stability. |
| Gaskets for medical or healthcare equipment | Commonly used in applications requiring physiological inertness, cleanability and specific formulations. |
| Sealing profiles for electrical or electronic equipment | Good stability, insulation properties and resistance to environmental ageing. |
| Membranes, plugs or flexible parts exposed to extreme cold | Retains elasticity at low temperatures better than many conventional elastomers. |
Choosing the Right Material from the Start
Selecting the right elastomer helps prevent issues related to the performance, durability or manufacturing feasibility of a part.
The Importance of Assessing Actual Working Conditions
| Criteria | Silicone | EPDM |
|---|---|---|
| High temperature | Very good | Good/Moderate |
| Extreme cold | Very good | Good |
| Hot water/steam | Variable depending on grade | Very good |
| Ozone/UV/weathering | Very good | Excellent |
| Oils/fuels | Limited | Not recommended |
| Cost | Higher | More competitive |
| Food/healthcare | Very common with certified grades | Possible with certified grades |
The choice between EPDM and silicone does not depend on a single factor. Temperature, chemical exposure, regulatory requirements, environmental conditions or expected service life should be analysed together to select the most suitable material.
At MOELSI, we support our customers throughout the entire development process, providing advice on material selection and technical solutions in thermoset rubber and silicone. Not sure whether EPDM or silicone is right for your application? Contact our team and we will analyse your part requirements to assess the most suitable solution.
