EPDM

In brief

EPDM (ethylene propylene diene rubber, ethylene propylene diene monomer) is a synthetic rubber for sealing and protective applications where weathering, ozone, UV radiation, water or steam are the main loads.

• Typical strengths: high ozone and UV resistance, very good ageing behaviour, good elasticity.
• Typical areas of use: outdoor seals, housing and flange seals, profiles, protective and damping parts.
• Temperature range (typical): approx. −40 °C to +120 °C (depending on compound and crosslinking).
• Media: suitable for water, steam and many dilute acids and alkalis (check depending on application).

For practical implementation in operations, EPDM seals as well as EPDM sheets and cut pieces are relevant standard solutions. For applications with mineral oils, fuels and many non-polar solvents, NBR or FKM are often the more suitable material class.

Fundamentals and properties of EPDM

Definition

EPDM stands for ethylene propylene diene rubber (ethylene propylene diene monomer) and belongs to the group of saturated elastomers. In practice, EPDM is used primarily for seals and profiles when weathering, ozone, UV radiation and water are the main loads.

Typical strengths in use

• Weathering and ozone resistance: EPDM is suitable for outdoor applications with long-term weathering.
• Ageing behaviour: EPDM shows stable elasticity over long periods of use, depending on formulation and crosslinking.
• Water and steam: EPDM is frequently used in water applications as well as hot water/steam contact (check depending on application).

Typical characteristic values as a guide

• Hardness: frequently in the range 40–80 Shore A (depending on formulation).
• Temperature range: typically approx. −40 °C to +120 °C (depending on compound and crosslinking).
• Mechanics: good elasticity and resilience, design is based on compression set and application load.

For applications where oil or fuel contact is the driving requirement, a comparison with NBR or FKM is often drawn upon, as these material classes typically provide the better fit for this requirement profile.

Resistance and media

Water and steam

EPDM is very well suited for use in water applications as well as with hot water and steam. For this reason, the material is frequently used in sanitary, heating and industrial water systems. The specific suitability depends on temperature, pressure and type of crosslinking and should be checked on an application-specific basis.

Acids and alkalis

EPDM shows good resistance to many dilute acids and alkalis. As a result, the material is a common choice for seals and protective components in chemically moderate environments. Concentration, temperature and exposure time significantly influence the actual resistance.

Oils, fuels and non-polar media

With mineral oils, fuels and many non-polar solvents, EPDM is generally not suitable. In these applications, NBR or FKM are frequently used, as these elastomers exhibit significantly higher resistance to oil-based media.

For outdoor applications with additional media exposure, the combination of media resistance and EPDM seals is a frequent decision factor.

Temperature range and ageing resistance

Temperature range in continuous operation

EPDM is typically used in a temperature range of approx. −40 °C to +120 °C. Briefly, higher temperatures are also possible depending on compound and type of crosslinking. For design in continuous operation, duration of use, mechanical load and medium are decisive.

Cold flexibility

Due to its good elasticity at low temperatures, EPDM is suitable for applications where seals must remain flexible and functional even in frost. This is a significant advantage over many other elastomers in outdoor applications.

Ageing and weathering resistance

EPDM is characterised by high resistance to ozone, UV radiation and oxygen. As a result, the material structure remains stable over a long period, even under permanent weathering. In practice, this leads to long maintenance intervals and predictable service lives.

For permanently stressed outdoor applications, EPDM seals are frequently used when temperature changes and weathering are the dominant influencing factors.

Typical applications and areas of use of EPDM

Outdoor applications and construction

Due to its high weathering, ozone and UV resistance, EPDM is frequently used outdoors. Typical applications are seals on facades, roofs, doors, windows as well as structural protective and separating elements.

Sanitary, heating and water technology

EPDM is suitable for seals and moulded parts in water and hot water applications. In sanitary and heating technology, the material is used among other things for flat gaskets, O-rings and profiles.

Industry and mechanical engineering

In an industrial environment, EPDM is used when temperature changes, weathering influences or water exposure are the main focus. These include housing seals, protective profiles, damping elements and covers.

Profiles, sheets and moulded parts

EPDM is processed as a profile, sheet or moulded part. For flat seals or individual contours, rubber sheets made of EPDM as well as customer-specific cut pieces are common solutions.

Comparison of EPDM with other elastomers

EPDM or NBR

EPDM and NBR are frequently compared, as both materials are widespread in sealing technology. EPDM is particularly suitable for applications with water, steam, weathering and ozone. NBR is preferably used when mineral oils, lubricants or fuels are the main requirement.

EPDM or FKM

FKM is used primarily at high temperatures and in contact with aggressive media such as oils, fuels or chemicals. EPDM is the more economical solution when weathering resistance, ageing stability and water resistance are the main focus.

Overview for material selection

• EPDM: water, steam, outdoor area, UV and ozone exposure.
• NBR: oils, greases, fuels, hydraulic applications.
• FKM: high temperatures, aggressive media, chemical exposure.

For specific applications, a direct comparison with NBR and FKM is worthwhile in order to reliably substantiate the material selection.

Processing, shapes and delivery forms of EPDM

Sheets and cut pieces

EPDM is frequently supplied in the form of sheets. These are suitable for flat seals, covers or as starting material for individual cut pieces. Depending on the application, thickness, hardness and dimensions are adapted to the operating conditions.

Seals and moulded parts

For standardised applications, EPDM seals are available in various geometries. In addition, customer-specific moulded parts can be manufactured when series applications or special contours are required.

Profiles

EPDM profiles are used primarily in construction, vehicle manufacturing and mechanical engineering. They serve as sealing, protective or guiding elements and are available in various cross-sections.

For flat applications and technical cut pieces, rubber sheets made of EPDM are frequently used, while for moving or geometrically complex applications EPDM seals represent the common solution.

Frequently asked questions about EPDM (FAQ)

What is EPDM?

EPDM is the abbreviation for ethylene propylene diene rubber. The material belongs to the synthetic elastomers and is used primarily for seals, profiles and protective parts under weathering, water and ozone exposure.

Is EPDM suitable for outdoor use?

EPDM is very well suited for outdoor use. The material is resistant to UV radiation, ozone and weathering and is therefore frequently used for outdoor seals and profiles.

Is EPDM oil- or fuel-resistant?

EPDM is typically used with water, steam and aqueous media. For applications with mineral oils or fuels, NBR or FKM are frequently chosen in practice.

What temperature range does EPDM cover?

The typical service temperature range of EPDM is approx. −40 °C to +120 °C. The actually permissible range depends on compound, type of crosslinking and duration of use.

What are EPDM seals used for?

EPDM seals are used among other things in sanitary technology, mechanical engineering, construction as well as in water-carrying systems. Typical applications are flange seals, housing seals and profiles.

In what forms is EPDM available?

EPDM is available as a sheet, profile, seal or moulded part. For flat applications, rubber sheets are frequently used, while for defined geometries EPDM seals are used.