Ethylene Propylene
(EPDM)

EPDM (Ethylene‑Propylene / Ethylene‑Propylene‑Diene Elastomer) offers a robust, flexible sealing material widely used across many industries. EPDM’s versatility stems from its excellent chemical, thermal and environmental resistance, making it an ideal choice for demanding sealing applications.

What is EP vs. EPDM?

• EP (Ethylene‑Propylene): a copolymer of ethylene and propylene. Typically only sulphur‑cured, EP delivers the basic benefits of this elastomer family.
• EPDM (Ethylene‑Propylene‑Diene Monomer): contains a third monomer (a diene), enabling cross‑linking that provides enhanced physical properties. EPDM can be cured via sulphur or peroxide; peroxide‑cured grades in particular offer superior high‑temperature and compression‑set performance.

Because the two are closely related, the terms “EP” and “EPDM” are sometimes used interchangeably — though differences in curing and performance exist.

Key Properties & Performance

Here are the main characteristics that make EPDM a go-to for many sealing and gasket applications:

• Wide Temperature Range: EPDM remains flexible and functional over a broad range — from as low as –50 °C (and down to –70 °C in some grades) up to +120 °C under normal conditions; special peroxide‑cured grades can handle continuous service around +150 °C (302 °F).
• Excellent Weather, Ozone & UV Resistance: The saturated polymer backbone makes EPDM highly resistant to ozone, oxygen, UV radiation and general environmental ageing — superior to many other elastomers for outdoor exposure.
• Strong Chemical & Water/Steam Resistance: EPDM shows good resistance to water, hot water, steam, many polar chemicals (acids, alkalis, glycols, alcohols), certain solvents and hydraulic fluids (e.g. phosphate‑ester based or glycol-based). This makes it suitable for plumbing, water systems, HVAC, and automotive coolant or brake systems.
• Low Compression Set & Good Elasticity: Even under long-term compression, EPDM tends to maintain its shape, ensuring reliable sealing over time. It also retains flexibility at low temperatures.
• Good Tear, Abrasion & Mechanical Properties (Varies by Grade): Tensile strength can reach ~20 MPa (depending on formulation), and elongation at break often exceeds 150%, ensuring a balance of strength and flexibility for gaskets, O‑rings, hoses, and seals.
• Electrical Insulation: EPDM is a good electrical insulator, making it useful for cable insulation or electrical sealing needs.
• Compliance for Drinking Water & Food Contact: Analysed and formulated EPDM grades can meet regulatory standards for potable water (e.g. NSF‑61, WRAS / KTW / WRC) and food‑grade applications, making them suitable for plumbing, sanitary equipment, and hygienic sealing.

Typical Applications

Because of this combination of properties, EPDM is widely used for:

• Seals, O‑rings and gaskets in drinking water systems, plumbing, domestic water appliances.
• Automotive applications: coolant hoses, brake fluid seals (for compatible fluids), weather‑stripping, window / door seals, and other non-oil‑exposed parts.
• Outdoor and environmental seals: roofing membranes, weather sealing, construction sealing, window gaskets — where UV, ozone, moisture and temperature cycling are significant.
• Industrial & chemical environments: seals for water, steam, acids/alkalis, glycol‑based fluids, and certain hydraulic systems; hoses and gaskets for HVAC, boilers, steam equipment, and water-treatment systems.
• Electrical insulation and sealing — cable jacketing, electrical conduit seals, etc.

Why Choose EPDM — and Which Grade

EPDM represents a well-balanced elastomer choice when you need:

• Strong resistance to weather, ozone, UV, water, steam, acids‑alkalis, glycols, and many polar chemicals
• Reliable sealing performance over a wide temperature and environmental range
• Compliance with potable water, food or hygiene standards (for WRAS / NSF 61 / FDA / USP‑Class VI / 3A grades)
• Versatility — from automotive to plumbing, HVAC, construction, electrical insulation, and chemical processing

When selecting EPDM for your application, it’s important to choose the right compound grade & curing method:

• For general‑purpose gaskets and seals, sulphur‑cured EPDM may suffice.
• For demanding environments (high temperature, steam, chemical exposure, long-term compression), peroxide‑cured EPDM offers better long-term stability and performance.

Summary

EPDM is a durable, versatile, and cost‑effective elastomer that performs well in a wide range of sealing and gasket applications — especially where exposure to weather, water, steam, chemicals, or UV is a concern. However, its poor resistance to petroleum‑based fluids and bonding challenges mean it must be selected with care. When used appropriately — and in the right grade — EPDM delivers long-lasting, reliable sealing across plumbing, automotive, industrial, construction, and electrical applications.

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Ethylene-Propylene is not resistant to petroleum products (mineral oils, greases and fuels) and offers no resistance to hydrocarbon fluids.

Please note: This Material Data Sheet section is to be used as a professional guide only. Eastern Seals (UK) Ltd may source their products from a variety of Quality Approved Suppliers and the data shown should not be relied upon by any purchaser without verification of material source.

ES REF	Colour	Temp Range	Hardness	Notes	Data Sheet
EP70	BLACK	-55°C to +125°C	70	General purpose EPDM.	EP70
EP70 FDA	BLACK	-55°C to +125°C	70	Food quality. Complies to FDA 21 CFR 177.2600.	EP70 FDA
EP70PC	BLACK	-55°C to +125°C	70	Peroxide cured EPDM offers improved compression set and higher temperature stability.	EP70 PC
EP70PC WRAS / NSF	BLACK	-55°C to +150°C	70	WRAS / NSF 61 / UL157 Approved.	EP70PC WRAS/NSF
EP70 WRAS/USP Class VI	BLACK	-40°C to +145°C	70	WRAS approved . Compliant to FDA CFR 177.2600. Developed according to EC1935/2004. Meets requirements of the 3A sanitary standards. Tested and certified by Toxicon laboratory to be in compliance with the criteria of US Pharmacopeia, Class VI Biological Test for Plastics.	EP70 WRAS USP Class VI