Ethylene propylene diene rubber (EPDM): properties and applications / Articles

Ethylene propylene diene rubber (EPDM) is a synthetic elastomer, a copolymer of ethylene, propylene and a small amount of a non-conjugated diene monomer. Thanks to its saturated backbone, containing double bonds only in the side diene units, this rubber possesses exceptional resistance to ozone, oxygen, UV radiation and weathering. In Russia, this material is known as SKEPT (synthetic ethylene-propylene terpolymer rubber), while in international practice it is referred to as EPDM.

Chemical Structure and Classification

Ethylene-propylene rubbers are divided into two main groups: binary copolymers of ethylene and propylene (EPM) and terpolymers with a diene monomer (EPDM). It is the presence of the diene monomer that enables sulfur vulcanisation, making EPDM a more technologically advanced and sought-after material. Ethylidene norbornene (ENB) or dicyclopentadiene (DCPD) are typically used as the diene monomer.

Production Technology

EPDM production is based on the copolymerisation of ethylene, propylene and a diene monomer. Polymerisation is carried out in solution or slurry in the presence of catalyst systems, most often based on vanadium compounds or metallocene catalysts. Modern technologies allow the production of rubbers with a specified content of ethylene, propylene and diene, which determines their properties.

Main Grades and Characteristics

In Russia, the main producer of EPDM is the Ufaorgsintez plant (part of Rosneft), which produces a wide range of grades, including SKEPT-E-30, SKEPT-E-40, SKEPT-E-50, SKEPT-E-60, SKEPT-E-70 and SKEPT-E-80.

SKEPT-40 — a copolymer of ethylene, propylene and dicyclopentadiene. Mooney viscosity ML 1+4 (100 °C) is 36–45 units. Tensile strength — not less than 180 kgf/cm², elongation at break — not less than 350%. Density at 20 °C — 0.85–0.87 g/cm³.

SKEPT-50 — grade with Mooney viscosity of 46–55 units and a mass fraction of dicyclopentadiene units of 5.8–7.2%. It possesses high physical and mechanical properties, chemical, weather and heat resistance, low-temperature resistance and excellent dielectric properties.

Physical, Mechanical and Chemical Properties

Ozone and Weather Resistance. This is the key advantage of EPDM. The saturated backbone makes the material exceptionally resistant to ozone cracking and UV radiation, ensuring the durability of outdoor products for over 50 years.

Heat Resistance. EPDM retains elasticity over a wide temperature range: from –50 °C to +150 °C. The continuous operating temperature is from –30 °C to +120 °C.

Chemical Resistance. EPDM is resistant to hot and cold water, steam, acids, alkalis, alcohols, glycols and brake fluids. It is not resistant to mineral oils, gasoline and chlorinated hydrocarbons.

Dielectric Properties. EPDM has high electrical insulation characteristics, allowing its use in the cable industry. Dielectric strength is 28–32 kV/mm.

Mechanical Properties. Tensile strength of EPDM vulcanisates is 10–20 MPa, hardness — 30–90 Shore A, density — 1.15 g/cm³.

Advantages and Disadvantages

Key Advantages:

Exceptional resistance to ozone, UV radiation and weathering
Wide operating temperature range
High chemical resistance to water, steam, acids and alkalis
Excellent dielectric properties
Durability (product service life over 50 years)

Main Disadvantages:

Low resistance to oils, gasoline and chlorinated hydrocarbons
Reduced adhesion to metals
Tendency to swell in non-polar solvents
Limited low-temperature flexibility (down to –50 °C)

Applications

Automotive Industry. This is the largest consumption segment for EPDM — over 45% of global volume. The material is used for door, window, trunk and hood seals, glass profiles, vibration and noise-absorbing components, cooling and heating system tubes and hoses, cuffs and seals.

Construction and Roofing. EPDM is widely used for roofing membranes, waterproofing materials, geomembranes for ponds, reservoirs and waste storage. EPDM-based roofing membranes have been in service in the USA and Canada for over 40 years, with a service life of 50+ years.

Cable Industry. EPDM is used for insulation of low and medium voltage cables, as well as in special cable accessories. The material provides increased flexibility and improved processability in insulation manufacturing.

Rubber Technical Products. Production of sealing profiles for windows and doors, air and water hoses, air ducts, conveyor belts, drive belts, seals for household appliances (washing machines, refrigerators).

Sports and Children's Surfaces. EPDM granules are used to create safe surfaces for children's and sports playgrounds, running tracks. The material is resistant to spikes, UV radiation and wear.

Medical Products. EPDM is used for seals in medical equipment, in dialysis systems, thanks to compatibility with low pH and high chemical resistance.

Consumer Goods. Production of shoe soles, garden tool grips, toothbrushes, tableware and toys.

Global Market

The global EPDM market shows steady growth. In 2025, the market was valued at USD 4.93 billion. It is projected to reach USD 6.50 billion by 2034 at a CAGR of 4.5%. In physical terms, global EPDM production reached 1,788 kilotons in 2025 at an average price of USD 3,020 per tonne.

The Asia-Pacific region dominates the market, with China being the largest producer and consumer. In 2025, China's EPDM capacity reached 43,500 tonnes, with an import dependency of 39.4%. Key players in the global market include Dow, ExxonMobil, Lanxess, SK Chemical, Mitsui Chemicals, as well as Chinese producers.

Conclusion

Ethylene propylene diene rubber (EPDM) is a unique synthetic elastomer combining exceptional resistance to ozone, UV radiation, weathering and a wide operating temperature range. Thanks to these properties, EPDM finds wide application in the automotive industry, construction, cable industry, rubber technical products and sports surfaces. The development of production in Russia (mastering SKEPT grades at Ufaorgsintez) and the expansion of global capacities ensure sustainable growth of this material's market in the long term.