EPM HE
Grade
also Vistalon
HE = 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.
Values for the HE 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 |
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 |
HEThis page 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 HE?
EPM HE is EPM in the HE grade — ethylene ≥ 65 %: crystalline, high green strength and filler loading, best for extruded profiles, cable jackets and PP modification; stiffer and worse at low temperature. EPM HE has a tensile strength of 18 MPa (2.61 ksi), weaker than 70% of polymer grades. Elongation at break is 350% and the elastic modulus is 0.02 GPa (0.0029 Msi). EPM HE has a density of 0.87 g/cm³ (0.0314 lb/in³), lighter than 83% of polymer grades. Its glass-transition temperature is -55°C (-67 °F). SHA70 is the default condition FabDigit quotes; HE 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
- Lightweight — 0.87 g/cm³ (0.0314 lb/in³), better than 83% of polymer grades
- Conducts heat well — 0.3 W/m·K (0.173 BTU/hr·ft·°F), better than 83% of polymer grades
Limitations
- Difficult to machine — 25/100, worse than 93% of polymer grades
- High mold shrinkage — 2.2%, worse than 87% of polymer grades
- Absorbs moisture — dry before molding — 0.8%, worse than 80% of polymer grades
- Low stiffness — 0.02 GPa (0.0029 Msi), worse than 75% of polymer grades
EPM HE properties
Typical room-temperature values for EPM HE; 16 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 HE has a density of 0.87 g/cm³ (0.0314 lb/in³), lighter than 83% of polymer grades. Its glass-transition temperature is -55°C (-67 °F).
Mechanical9
EPM HE has a tensile strength of 18 MPa (2.61 ksi), weaker than 70% of polymer grades. Elongation at break is 350% and the elastic modulus is 0.02 GPa (0.0029 Msi).
Thermal8
EPM HE is rated for continuous service to 150°C (302 °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).
Electrical5
EPM HE is an electrical insulator with a dielectric strength of 25 kV/mm (635 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 HE 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 HE's machinability is poor (25/100, worse than 93% of polymer grades); formability very good (80/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with EPM HE
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 HE — frequently asked
What is EPM HE used for?
EPM HE 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 HE?
EPM HE has a typical tensile strength of 18 MPa (2.61 ksi) — weaker than 70% of polymer grades. Strength varies by condition: see the 13 listed tempers.
Is EPM HE easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of polymer grades). Not machined conventionally — die-cut, waterjet or cryogenically deflash; grinding needs sharp tools and coolant to avoid smearing.
Can EPM HE 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 HE?
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 HE 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 HE?
EPM HE 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.
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.