EPDM seals compared with NBR & silicone

EPDM seals

are indispensable components in a wide variety of technical applications – from vehicles and machines to household appliances and medical devices. Their main task is to prevent the escape or ingress of liquids, gases or dust and thus to ensure the functionality and safety of a system.

Choosing the right sealing material is crucial, as every material has its own strengths and weaknesses and only delivers optimum performance under certain conditions. The wrong material can lead to premature wear, increased maintenance costs or even failures. Anyone who knows the differences between the common materials can decide in a targeted way which product offers the best combination of durability, cost and performance for the respective application.

Properties of EPDM seals

EPDM (ethylene propylene diene rubber) is a synthetic rubber known for its exceptional resistance to weathering, ozone and UV radiation. The material retains its elasticity even under large temperature fluctuations and is therefore particularly popular outdoors. EPDM seals are also water-resistant and show good resistance to diluted acids, alkalis and many chemical substances.

Advantages:

• Excellent ageing resistance and durability outdoors
• Flexible at temperatures from approx. -40 °C to +120 °C (short-term up to 150 °C)
• Resistant to water, steam, many chemicals and cleaning agents

Disadvantages:

• Not resistant to mineral oils, greases and fuels
• Limited mechanical strength in oily environments

Typical areas of use: roof and façade seals, window and door profiles, hoses and seals in heating and sanitary installations.

Properties of NBR seals

NBR (nitrile butadiene rubber) is characterised by a very high resistance to oils, greases and fuels and is therefore preferably used in industrial applications in which contact with such media is unavoidable. The material is abrasion-resistant and resistant to mechanical stress.

Advantages:

• Excellent oil and fuel resistance
• Good abrasion resistance and mechanical load capacity
• Temperature range from approx. -30 °C to +100 °C (short-term up to 120 °C)

Disadvantages:

• Poor weathering and ozone resistance
• Not suitable for permanent outdoor use without protection

Typical areas of use: hydraulic and pneumatic systems, fuel lines, seals in machines and engines.

Properties of silicone seals

Silicone (VMQ) is an extremely flexible and temperature-resistant material that retains its elasticity both in extreme cold and at high temperatures. Silicone is also often food-safe and therefore ideal for applications in the food and medical technology sectors.

Advantages:

• Wide temperature range from approx. -60 °C to +200 °C (short-term up to 230 °C)
• Very good UV, ozone and weathering resistance
• Odourless and tasteless, often food-safe

Disadvantages:

• Lower mechanical strength and abrasion resistance
• Limited resistance to oils and many solvents

Typical areas of use: oven seals, refrigeration appliance systems, seals in laboratory equipment, medical hoses and seals in the food industry.

Comparison of EPDM vs. NBR vs. silicone

Property	EPDM	NBR	Silicone	Typical areas of use
Temperature range	-40 °C to +120 °C	-30 °C to +100 °C	-60 °C to +200 °C	Depending on medium and temperature
Weathering resistance	Very good	Low	Very good	Outdoors, construction, machines
Oil and fuel resistance	Low	Very good	Low to medium	Industry, engines, hydraulics
UV/ozone resistance	Very good	Low	Very good	Outdoor installations, vehicles
Mechanical strength	Medium	High	Medium	Mechanical engineering, automotive
Price level	Medium	Low to medium	Medium to high	Cost-oriented projects

Which material for which application?

• Outdoors with high exposure to weathering: EPDM or silicone
• Contact with oils, greases or fuels: NBR
• High temperatures or food contact: silicone
• Cost-effective standard application: NBR, provided there is no exposure to weathering

Care and service life

Seals should be checked regularly for wear, cracks or material changes in order to avoid malfunctions and consequential damage. For EPDM, storage in a cool, dry place protected from UV light is recommended in order to preserve its excellent weathering resistance. NBR should be protected from direct sunlight and ozone sources, as these make the material brittle. Silicone requires less protection from UV, but should be stored clean and dry in order to preserve its food safety.

Careful cleaning with mild cleaning agents and without aggressive chemicals extends the service life of all materials. During installation, ensure clean sealing surfaces in order to avoid damage and leaks. For some materials there are special care products that can preserve elasticity and improve resistance to environmental influences.

Conclusion

The choice between EPDM, NBR and silicone depends largely on the area of use, the ambient conditions and the required properties.

EPDM offers excellent weathering resistance and is ideal for outdoor use, NBR is unbeatable in oily media and areas subject to high mechanical stress, while silicone impresses with extreme temperature resistance and food safety.

For construction and façade technology, EPDM is often the first choice, in mechanical engineering and in the automotive industry NBR dominates, and in food or medical technology silicone is almost indispensable. Anyone who knows the material properties and chooses carefully can reduce downtime, lower maintenance costs and ensure operational safety in the long term. A well-considered material decision is therefore not only technically but also economically advantageous.

FAQ

Are EPDM seals food-safe? There are special EPDM grades that are approved for the food sector.

Which seal lasts the longest? That depends on the area of use – outdoors usually EPDM or silicone, in oily environments NBR.

Can seals be replaced yourself? Yes, in many applications replacement is straightforward. Pay attention to the exact dimensions and material properties.