EPM ELEC
Additive grade
also Vistalon
ELEC = electrical/EPR insulation grade
Choose for MV/LV cable insulation, cable accessories and HV components where volume resistivity and wet electrical ageing matter.
Values for the ELEC condition
Other EPM grades and fills
EPM is listed in 13 conditions; see the grade overview at EPM.
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 |
ELECThis page 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 |
What is EPM ELEC?
EPM ELEC is EPM in the ELEC grade — choose for MV/LV cable insulation, cable accessories and HV components where volume resistivity and wet electrical ageing matter. EPM ELEC has a tensile strength of 9 MPa (1.23 ksi), weaker than 80% of polymer grades. Elongation at break is 350% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi). EPM ELEC has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is -55°C (-67 °F). SHA70 is the default condition FabDigit quotes; ELEC is available on request or by drawing note.
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 — 350%, better than 84% of polymer grades
- Forms and bends easily — 85/100, better than 81% of polymer grades
- Low embodied carbon — 3.4 kg CO₂/kg, better than 76% 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 ELEC properties
Typical room-temperature values for EPM ELEC; 10 are specific to this condition. Other listed values are EPM reference data and may not represent this condition. Bars are the position among polymer grades.
Physical3
EPM ELEC has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is -55°C (-67 °F).
Mechanical9
EPM ELEC has a tensile strength of 9 MPa (1.23 ksi), weaker than 80% of polymer grades. Elongation at break is 350% and the elastic modulus is 0.01 GPa (8.7×10⁻⁴ Msi).
Thermal8
EPM ELEC is rated for continuous service to 105°C (221 °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 ELEC is an electrical insulator with a dielectric strength of 28 kV/mm (711.2 V/mil) and a resistivity of 1×10¹⁴ 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 ELEC 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 ELEC's machinability is poor (30/100, worse than 87% of polymer grades); formability excellent (85/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with EPM ELEC
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.
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.
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) | — |
EPM ELEC — frequently asked
What is EPM ELEC used for?
EPM ELEC 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 ELEC?
EPM ELEC has a typical tensile strength of 9 MPa (1.23 ksi) — weaker than 80% of polymer grades. Strength varies by condition: see the 13 listed tempers.
Is EPM ELEC 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 ELEC 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 ELEC?
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 ELEC 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 ELEC?
EPM ELEC is rated for continuous use to about 105°C (221 °F), and briefly to 175°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.