EPDM
also Ethylene Propylene Diene Monomer, Nordel
EPDM is a saturated-backbone terpolymer of ethylene, propylene and a diene (usually ENB) that is compounded with carbon black, oil and filler and vulcanized with sulfur or peroxide.
Values for the Solid condition
EPDM grades and fills
EPDM is supplied in 12 conditions, soft to hard. Solid is the default FabDigit quotes; the values on this page are for it.
Compare all 12 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Closed-cell / open-cell cellular EPDM | Pick for low-closure-force dust, water and acoustic sealing (cabinet gaskets, door seals) where compression load must stay low. | 2 | 200 | 20 Shore A | |
Shore A 40 | Soft grade for low-force conformal sealing on rough or uneven flanges. | 8 | 550 | 40 Shore A | |
Flame-retardant | Use for rail, cable-accessory and enclosure seals needing UL 94 V-0 or EN 45545 fire performance; ATH loading raises stiffness and cuts elongation. | 8 | 250 | 25 Shore D | |
Shore A 50 | Compromise durometer for low-pressure static gaskets needing good conformability. | 9 | 500 | 50 Shore A | |
Carbon-black conductive / semiconductive grade | Highly conductive-black loaded compound for cable semicon layers, EMI/static-dissipative gaskets and grounding pads. | 10 | 250 | 25 Shore D | |
Shore A 60 | General sheet/extrusion durometer balancing sealing force and abrasion life. | 11 | 450 | 60 Shore A | |
SolidDefault Dense vulcanized EPDM compound | Default dense rubber for O-rings, gaskets, weatherstrip and hose where a pressure-tight, load-bearing seal is needed. | 12 | 400 | 22 Shore D | |
Shore A 70 | Industry-default hardness for O-rings and dynamic-pressure static seals. | 12 | 400 | 22 Shore D | |
Sulfur-cured | Lowest-cost, fastest-curing option for weatherstrip, roofing and general gaskets below ~120 °C. | 12 | 420 | 22 Shore D | |
Shore A 80 | Use for higher-pressure seals, backup rings and extrusion-resistant profiles. | 14 | 300 | 30 Shore D | |
Peroxide-cured | Choose for steam, hot water and 150 °C air service, and wherever low compression set or non-staining/low-extractable behaviour is required. | 15 | 350 | 22 Shore D | |
Shore A 90 | Rigid rubber for bushings, wheel treads and highly extruded seal geometries. | 16 | 200 | 38 Shore D |
Supply forms, finishes and certifications
Ways EPDM is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FDA | FDA / potable-water grade | Certification |
What is EPDM?
EPDM is a saturated-backbone terpolymer of ethylene, propylene and a diene (usually ENB) that is compounded with carbon black, oil and filler and vulcanized with sulfur or peroxide. It is the standard choice for outdoor seals, roofing membrane, automotive weatherstrip, hoses and steam/hot-water gaskets because of outstanding ozone, UV, weathering and hot-water/steam resistance plus good electrical insulation at low cost. Its main limitation is very poor resistance to mineral oils, fuels and hydrocarbon solvents, and it is hard to bond to itself or to substrates without surface treatment. EPDM has a density of 1.15 g/cm³ (0.0415 lb/in³), lighter than 57% of polymer grades. Its glass-transition temperature is -55°C (-67 °F). EPDM has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 400% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi).
What is EPDM used for?
- Automotive window and door weatherstrip
- Roofing membranes
- Steam and hot-water gaskets
- Coolant and radiator hoses
- Sponge sealing profiles for enclosures
- HVAC duct and access-panel gaskets
- Electrical insulation grommets and boots
Advantages
- Good UV / weathering resistance — 95/100, better than 95% of polymer grades
- Forms and bends easily — 90/100, better than 91% of polymer grades
- Ductile — tolerates forming and impact — 400%, better than 86% of polymer grades
- Conducts heat well — 0.3 W/m·K (0.173 BTU/hr·ft·°F), better than 83% of polymer grades
Limitations
- Hard to polish — 20/100, worse than 95% of polymer grades
- High mold shrinkage — 2.5%, worse than 93% of polymer grades
- Difficult to machine — 30/100, worse than 87% of polymer grades
- Low stiffness — 0.01 GPa (8.7×10⁻⁴ Msi), worse than 86% of polymer grades
- Difficult to weld — 15/100, worse than 78% of polymer grades
EPDM properties
Typical room-temperature values for EPDM-Solid; bars are the position among polymer grades.
Physical3
EPDM has a density of 1.15 g/cm³ (0.0415 lb/in³), lighter than 57% of polymer grades. Its glass-transition temperature is -55°C (-67 °F).
Mechanical10
EPDM has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 400% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi).
Thermal8
EPDM is rated for continuous service to 120°C (248 °F). It conducts heat at 0.3 W/m·K (0.173 BTU/hr·ft·°F), better than 83% of polymer grades. Thermal expansion is 180 µm/m·K (100 µin/in·°F).
Electrical6
EPDM is an electrical insulator with a dielectric strength of 25 kV/mm (635 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 65% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of EPDM takes about 95 MJ of energy and emits 4 kg of CO₂ — less than 70% of polymer grades. Typical recycled content is 5%.
Manufacturability7
EPDM's machinability is poor (30/100, worse than 87% of polymer grades); weldability poor (15/100); formability excellent (90/100).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. EPDM is highlighted; hover a dot for its name, or open the interactive family chart.
Working with EPDM
Is EPDM easy to machine?
Best die-cut, waterjet or knife/CNC-blade cut with soap lubricant; milling and drilling smear and tear unless the part is frozen or a sharp hollow punch is used.
Can EPDM be welded?
Not thermally weldable — join by hot vulcanized splice, uncured tape splice, or cyanoacrylate/CR contact adhesive after abrasion plus primer.
Can EPDM be formed, bent or molded?
Mix on internal mixer/two-roll mill, then extrude profiles or compression/transfer/injection mold and vulcanize ~160–200 °C; sponge grades use chemical blowing agents with a matched slow cure.
Manufacturability
The process limits FabDigit applies to EPDM. Every EPDM part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
Injection molding
| Mold shrinkage | — |
|---|---|
| Wall thickness | — – — |
| Recommended draft | — |
| Pre-drying | — |
EPDM chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| ethylene (C2 units)polymer C2 content; high-C2 grades are semi-crystalline | 45 – 75 | 60 |
| ENB diene (5-ethylidene-2-norbornene)cure site for sulfur vulcanization; DCPD/VNB used in some grades | 0.5 – 12 | 5 |
| carbon black (N550/N660)phr on polymer, in the compounded rubber | 20 – 90 | 60 |
| paraffinic process oilphr; oil-extended polymers supplied pre-oiled | 10 – 100 | 50 |
| calcium carbonate / clay fillerphr, cost filler | 0 – 80 | 30 |
| zinc oxide + stearic acidphr, activators | ≈ 6 | 6 |
| sulfur + accelerators or organic peroxidphr, cure system | 1 – 8 | 3 |
| propylene (C3 units)balance of polymer backbone | ≥ 20 (balance) |
What surface finishes work on EPDM?
Surface finish comes from the mold or extrusion die; flash removed by cryogenic deflashing, and paintability/bondability requires corona, plasma or chlorination pretreatment.
Surface treatments FabDigit runs on polymer parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Injection Molding Coating
Metallization / Functional
Equivalent designations
Standards and trade names that resolve to EPDM in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Ethylene Propylene Diene MonomerNordelVistalonEthylene Propylene
- Also called
- EPT
How much does EPDM cost?
EPDM is a standard-cost polymer ($$), cheaper than about 81% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
EPDM — frequently asked
What is EPDM used for?
EPDM is typically used for automotive window and door weatherstrip, roofing membranes, steam and hot-water gaskets, coolant and radiator hoses, sponge sealing profiles for enclosures and HVAC duct and access-panel gaskets. In short: weatherproof rubber.
What is the tensile strength of EPDM?
EPDM has a typical tensile strength of 12 MPa (1.74 ksi) — weaker than 76% of polymer grades. Strength varies by condition: see the 12 listed tempers.
Is EPDM easy to machine?
Not especially — machinability is rated poor (30/100, worse than 87% of polymer grades). Best die-cut, waterjet or knife/CNC-blade cut with soap lubricant; milling and drilling smear and tear unless the part is frozen or a sharp hollow punch is used.
Can EPDM be welded?
Not readily — weldability is rated poor (15/100). Not thermally weldable — join by hot vulcanized splice, uncured tape splice, or cyanoacrylate/CR contact adhesive after abrasion plus primer.
What surface finishes work on EPDM?
Surface finish comes from the mold or extrusion die; flash removed by cryogenic deflashing, and paintability/bondability requires corona, plasma or chlorination pretreatment.
Can EPDM be formed, bent or molded?
Mix on internal mixer/two-roll mill, then extrude profiles or compression/transfer/injection mold and vulcanize ~160–200 °C; sponge grades use chemical blowing agents with a matched slow cure.
What is the maximum service temperature of EPDM?
EPDM is rated for continuous use to about 120°C (248 °F), and briefly to 160°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does EPDM cost?
EPDM is a standard-cost polymer ($$), cheaper than about 81% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in EPDM?
Yes — EPDM is available for injection molding; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM D2000 — Rubber Products in Automotive Applications (classification AA/BA/CA/DA lines) — ASTM (2023)
- ASTM D1418 — Rubber and Rubber Latices Nomenclature (EPDM) — ASTM (2022)
- Vistalon EPDM grade and compound data — ExxonMobil Chemical (2023)
- Nordel IP EPDM technical information — Dow (2022)
- Keltan EPDM compounding guides — Arlanxeo (2023)
- ASM Engineered Materials Handbook Vol. 2 — Engineering Plastics/Elastomers — ASM International (1988)
- O-ring and elastomer chemical compatibility / property tables — Parker Hannifin O-Ring Handbook (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.