EPM
also Vistalon
EPM (Vistalon) is a saturated ethylene-propylene copolymer with no diene cure sites, so it is peroxide-cured only; grades cover 40–90 Shore A plus electrical, ESD, FDA, FR, oil-extended and sponge compounds.
Reference datasheet — EPM is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the SHA70 condition
EPM grades and fills
EPM is supplied in 13 conditions, soft to hard. SHA70 is the default FabDigit quotes; the values on this page are for it.
Compare all 13 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Closed-cell expanded compound | Chemically blown closed-cell sponge for weather seals, HVAC gaskets and thermal insulation; sealing by low closure force, not by pressure retention. | 2 | 180 | 15 Shore A | |
Uncured gum copolymer | Base polymer as bought (Vistalon 404/504, Keltan, Dutral CO) for compounding, PP impact modification or lube VI improver — no vulcanizate strength. | 2 | 800 | 45 Shore A | |
Flame-retardant (ATH / halogen-free) compound | Rail, marine and building cable/gasket applications needing low smoke, halogen-free flame retardance; heavily loaded so mechanicals drop. | 8 | 220 | 28 Shore D | |
Electrical/EPR insulation grade | Choose for MV/LV cable insulation, cable accessories and HV components where volume resistivity and wet electrical ageing matter. | 9 | 350 | 72 Shore A | |
Shore A 40 | Soft, high-elongation gaskets, diaphragms and low-closure-force seals. | 9 | 600 | 40 Shore A | |
Oil-extended (paraffinic plasticiser) compound | Low-cost, easy-processing extruded profiles and weatherstrip; higher compression set and more extractables. | 9 | 450 | 16 Shore D | |
Shore A 50 | Flexible sealing profiles and low-pressure static gaskets. | 11 | 520 | 50 Shore A | |
ESD/COND | For semiconductive cable screens, ESD rollers and static-dissipative seals; needs high black loading, so elongation drops. | 11 | 200 | 28 Shore D | |
Shore A 60 | General O-rings and hose covers where some conformability is still needed. | 13 | 420 | 60 Shore A | |
SHA70Default Shore A 70 | Default workhorse: O-rings, steam and hot-water seals, radiator/coolant hose, brake cups. | 14 | 320 | 70 Shore A | |
Shore A 80 | Higher-pressure seals, back-up rings, bushings and anti-extrusion parts. | 16 | 240 | 28 Shore D | |
Shore A 90 | Rigid mounts, wear pads and extrusion-resistant seat rings; low elongation and higher set. | 17 | 150 | 38 Shore D | |
High-ethylene (semi-crystalline) copolymer | Ethylene ≥ 65 %: crystalline, high green strength and filler loading, best for extruded profiles, cable jackets and PP modification; stiffer and worse at low temperature. | 18 | 350 | 75 Shore A |
Supply forms, finishes and certifications
Ways EPM 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 | Food/potable-water grade | Certification |
What is EPM?
EPM (Vistalon) is a saturated ethylene-propylene copolymer with no diene cure sites, so it is peroxide-cured only; grades cover 40–90 Shore A plus electrical, ESD, FDA, FR, oil-extended and sponge compounds. It suits heat, oxidation, ozone, steam and polar-fluid service: 1.12 g/cm³ density, 14 MPa tensile strength, 320 % elongation, about 6 MPa modulus and use to roughly 150 °C, in wire insulation, high-temperature seals and as a polyolefin impact modifier. It swells in mineral oils and fuels and cannot be sulfur co-cured with NR/SBR; use EPDM where a sulfur cure or faster cure rate is needed. EPM has a density of 1.12 g/cm³ (0.0405 lb/in³), lighter than 64% of polymer grades. Its glass-transition temperature is -55°C (-67 °F). EPM has a tensile strength of 14 MPa (2.03 ksi), weaker than 75% of polymer grades. Elongation at break is 320% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi).
What is EPM used for?
- wire insulation
- impact modifiers
- high-temp seals
Advantages
- Good UV / weathering resistance — 97/100, better than 98% of polymer grades
- Good corrosion resistance — 95/100, better than 97% of polymer grades
- Ductile — tolerates forming and impact — 320%, better than 82% of polymer grades
- Forms and bends easily — 85/100, better than 81% of polymer grades
- High service temperature — 150°C (302 °F), better than 79% of polymer grades
Limitations
- 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
- Absorbs moisture — dry before molding — 0.8%, worse than 80% of polymer grades
EPM properties
Typical room-temperature values for EPM-SHA70; bars are the position among polymer grades.
Physical3
EPM has a density of 1.12 g/cm³ (0.0405 lb/in³), lighter than 64% of polymer grades. Its glass-transition temperature is -55°C (-67 °F).
Mechanical9
EPM has a tensile strength of 14 MPa (2.03 ksi), weaker than 75% of polymer grades. Elongation at break is 320% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi).
Thermal8
EPM is rated for continuous service to 150°C (302 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 72% of polymer grades. Thermal expansion is 180 µm/m·K (100 µin/in·°F).
Electrical5
EPM is an electrical insulator with a dielectric strength of 25 kV/mm (635 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (95/100), better than 97% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of EPM takes about 95 MJ of energy and emits 3.4 kg of CO₂ — less than 70% of polymer grades. Typical recycled content is 2%.
Manufacturability4
EPM's machinability is poor (30/100, worse than 87% of polymer grades); formability excellent (85/100).
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. EPM is highlighted; hover a dot for its name, or open the interactive family chart.
Working with EPM
Is EPM easy to machine?
Not machined conventionally — die-cut, waterjet or cryogenically deflash; grinding needs sharp tools and coolant to avoid smearing.
Can EPM be welded?
Cannot be melt-welded; join by uncured-splice vulcanisation, hot-bond tape or by cyanoacrylate/polyurethane adhesive after plasma or chlorination surface treatment.
Can EPM be formed, bent or molded?
Compression, transfer or injection molded and extruded; peroxide cure only (170–190 °C), needs an inert/pressurised cure or post-cure because air inhibits surface crosslinking, and it cannot be co-cured with sulfur-cured rubbers.
EPM 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 |
|---|---|---|
| ethylenewt % of the copolymer; >65 % gives semi-crystalline grades | 45 – 75 | 55 |
| carbon black (N550/N660)wt % of the compound; replaced by clay/talc/ATH in light-coloured grades | 0 – 45 | 25 |
| paraffinic process oilwt % of compound | 0 – 30 | 12 |
| organic peroxide (e.g. DCP) + coagentsole practical cure system; sulfur cure not possible | 0.5 – 3 | 1.5 |
| ZnO / stearic acid / antioxidant | 1 – 6 | 3 |
| propyleneno diene termonomer — fully saturated backbone | ≥ 25 (balance) |
What surface finishes work on EPM?
No painting or plating; bonded-to-metal parts use phenolic/silane bonding agents, and talc or PTFE dusting/coating is used to reduce tack and friction.
Equivalent designations
Standards and trade names that resolve to EPM in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Vistalon
How much does EPM cost?
EPM is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
EPM — frequently asked
What is EPM used for?
EPM is typically used for wire insulation, impact modifiers and high-temp seals. In short: peroxide-cure-only EPDM alternative; maximum ozone and oxidation resistance; no diene cure sites.
What is the tensile strength of EPM?
EPM has a typical tensile strength of 14 MPa (2.03 ksi) — weaker than 75% of polymer grades. Strength varies by condition: see the 13 listed tempers.
Is EPM easy to machine?
Not especially — machinability is rated poor (30/100, worse than 87% of polymer grades). Not machined conventionally — die-cut, waterjet or cryogenically deflash; grinding needs sharp tools and coolant to avoid smearing.
Can EPM be welded?
Cannot be melt-welded; join by uncured-splice vulcanisation, hot-bond tape or by cyanoacrylate/polyurethane adhesive after plasma or chlorination surface treatment.
What surface finishes work on EPM?
No painting or plating; bonded-to-metal parts use phenolic/silane bonding agents, and talc or PTFE dusting/coating is used to reduce tack and friction.
Can EPM be formed, bent or molded?
Compression, transfer or injection molded and extruded; peroxide cure only (170–190 °C), needs an inert/pressurised cure or post-cure because air inhibits surface crosslinking, and it cannot be co-cured with sulfur-cured rubbers.
What is the maximum service temperature of EPM?
EPM is rated for continuous use to about 150°C (302 °F), and briefly to 175°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does EPM cost?
EPM is a standard-cost polymer ($$), cheaper than about 71% 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.
Sources
- ASTM D1418 — Rubber and Rubber Latices Nomenclature (EPM/EPDM) — ASTM International (2022)
- ASTM D2000 — Classification System for Rubber Products in Automotive Applications — ASTM International (2021)
- Vistalon ethylene-propylene copolymer grade data — ExxonMobil Chemical (2023)
- Keltan EPDM/EPM product range technical bulletins — ARLANXEO (2023)
- Engineered Materials Handbook Vol. 2 — Engineering Plastics / Elastomers — ASM International (1988)
- Rubber Technology Handbook (elastomer property tables) — Hanser (2012)
- CES/Granta EduPack elastomer records (EPDM/EPM) — Ansys Granta (2023)
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.