AEM A70
Hardness band · default condition
also Vamac
A70 = shore A 70
Use as the default 70 Shore A diamine-cured compound for automotive seals, gaskets and hose, giving the best balance of cost, heat and oil resistance with 150 °C service.
Values for the A70 condition
Other AEM grades and fills
AEM is listed in 10 conditions; see the grade overview at AEM.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Shore A 50 | Pick the soft Shore A 50 compound for seals and vibration dampers that need high elongation (350 %) and close conformability, accepting a tensile strength of only 8.5 MPa. | — | 9 | 350 | 12 Shore D |
Flame-retardant AEM compound | Pick for rail-transit and cable-jacket seals and boots with flame-retardant, low-smoke requirements; ATH/phosphorus loading raises density to 1.4 and cuts tensile to 9 MPa. | — | 9 | 200 | 24 Shore D |
Non-black / colorable compound | Use where light-coloured or colourable parts or higher electrical insulation are needed; mineral- or silica-filled compounds give 10 MPa tensile, slightly below carbon-black grades. | — | 10 | 260 | 21 Shore D |
Shore A 60 | Choose for hose inner liner layers and low-clamp-force seals that must conform to the mating face; the softer 60 Shore A compound gives 11 MPa tensile and 300 % elongation. | — | 11 | 300 | 16 Shore D |
Low-temperature grade | Pick for cold-start or cold-climate turbocharger hoses and seals needing flexibility below −40 °C; the −43 °C Tg comes with service temperature limited to 140 °C. | — | 11 | 300 | 18 Shore D |
Improved-processing / injection grade | Choose for high-volume injection moulding where smooth demoulding and low mould fouling matter; the improved-processing grade still gives 12 MPa tensile and 250 % elongation. | — | 12 | 250 | 20 Shore D |
A70DefaultThis page Shore A 70 | Use as the default 70 Shore A diamine-cured compound for automotive seals, gaskets and hose, giving the best balance of cost, heat and oil resistance with 150 °C service. | — | 13 | 250 | 22 Shore D |
High-heat grade | Use for turbocharger outlet and exhaust-side parts requiring 165–175 °C continuous heat; the high-acrylate polymer raises Tg to −25 °C, so cold flexibility is sacrificed. | — | 14 | 220 | 23 Shore D |
Shore A 80 | Pick for high-pressure seals, washers and support parts that must resist extrusion; the harder 80 Shore A compound raises tensile to 15 MPa but cuts elongation to 200 %. | — | 15 | 200 | 30 Shore D |
Shore A 90 | Choose this hardest, high-filler 90 Shore A grade for rigid gaskets, anti-extrusion rings and bonded rubber-to-metal parts; elongation drops to 150 % at 17 MPa tensile. | — | 17 | 150 | 40 Shore D |
What is AEM A70?
AEM A70 is AEM heat treated to A70 — use as the default 70 Shore A diamine-cured compound for automotive seals, gaskets and hose, giving the best balance of cost, heat and oil resistance with 150 °C service. AEM A70 has a tensile strength of 13 MPa (1.89 ksi), weaker than 75% of polymer grades. Elongation at break is 250% and the elastic modulus is 0.01 GPa (0.001 Msi). AEM A70 has a density of 1.2 g/cm³ (0.0434 lb/in³), heavier than 57% of polymer grades. Its glass-transition temperature is -33°C (-27 °F).
Advantages
- Good UV / weathering resistance — 90/100, better than 91% of polymer grades
- Forms and bends easily — 85/100, better than 81% of polymer grades
- Ductile — tolerates forming and impact — 250%, better than 79% of polymer grades
- High service temperature — 150°C (302 °F), better than 79% of polymer grades
Limitations
- Difficult to machine — 25/100, worse than 93% of polymer grades
- Absorbs moisture — dry before molding — 1.5%, worse than 91% of polymer grades
- High mold shrinkage — 2.2%, worse than 87% of polymer grades
- Low stiffness — 0.01 GPa (0.001 Msi), worse than 84% of polymer grades
- Difficult to weld — 12/100, worse than 80% of polymer grades
AEM A70 properties
Typical room-temperature values for AEM A70; 18 are specific to this condition. Other listed values are AEM reference data and may not represent this condition. Bars are the position among polymer grades.
Physical3
AEM A70 has a density of 1.2 g/cm³ (0.0434 lb/in³), heavier than 57% of polymer grades. Its glass-transition temperature is -33°C (-27 °F).
Mechanical9
AEM A70 has a tensile strength of 13 MPa (1.89 ksi), weaker than 75% of polymer grades. Elongation at break is 250% and the elastic modulus is 0.01 GPa (0.001 Msi).
Thermal8
AEM A70 is rated for continuous service to 150°C (302 °F). It conducts heat at 0.22 W/m·K (0.127 BTU/hr·ft·°F), better than 60% of polymer grades. Thermal expansion is 200 µm/m·K (111.1 µin/in·°F).
Electrical5
AEM A70 is an electrical insulator with a dielectric strength of 18 kV/mm (457.2 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), worse than 52% of polymer grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of AEM A70 takes about 125 MJ of energy and emits 5.5 kg of CO₂ — more than 75% of polymer grades. Typical recycled content is 0%.
Manufacturability6
AEM A70's machinability is poor (25/100, worse than 93% of polymer grades); weldability not recommended (12/100); formability excellent (85/100).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AEM A70
Is AEM easy to machine?
After vulcanisation the material is die-cut, water-jet cut or cryogenically turned; conventional cutting goes tacky and tears, so dimensional accuracy comes from the mould rather than machining.
Can AEM be welded?
As a thermoset elastomer it cannot be melt-welded; joints are adhesive-bonded or spliced by secondary vulcanisation, with hose ends bonded to metal or plastic inserts.
Can AEM be formed, bent or molded?
Compression, transfer or injection moulded at mould temperatures of 175–190 °C, followed by 4 h post-cure at 175 °C to stabilise compression set. Diamine cure systems need good venting and mould release.
What surface finishes work on AEM?
Bonds to metal inserts with primer plus adhesive; siloxane anti-stick coatings can be applied. Plating does not apply, and light-coloured parts require non-carbon-black formulations with antioxidant and UV packages.
AEM 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 |
|---|---|---|
| ethylenesaturated backbone segment, improves low-temperature flexibility | 50 – 70 | 60 |
| methyl acrylatepolar segment, provides oil and heat resistance | 30 – 50 | 39 |
| cure-site monomerterpolymer for diamine cure; zero in DP/peroxide grades | 0 – 1.5 | 1 |
| carbon black ( N550/N774, )phr, compounding ingredient, not part of the polymer | 20 – 60 | 35 |
| plasticizer + processing aids ( /phr; ether-ester plasticizer improves low-temperature behavior | 0 – 15 | 5 |
AEM A70 — frequently asked
What is AEM A70 used for?
AEM A70 is typically used for automotive seals, spark plug boots, wire jacketing and gaskets. In short: better cold flexibility than ACM; 150 °C heat and oil service; light-colour and FR grades.
What is the tensile strength of AEM A70?
AEM A70 has a typical tensile strength of 13 MPa (1.89 ksi) — weaker than 75% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is AEM A70 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of polymer grades). After vulcanisation the material is die-cut, water-jet cut or cryogenically turned; conventional cutting goes tacky and tears, so dimensional accuracy comes from the mould rather than machining.
Can AEM A70 be welded?
Not readily — weldability is rated not recommended (12/100). As a thermoset elastomer it cannot be melt-welded; joints are adhesive-bonded or spliced by secondary vulcanisation, with hose ends bonded to metal or plastic inserts.
What surface finishes work on AEM A70?
Bonds to metal inserts with primer plus adhesive; siloxane anti-stick coatings can be applied. Plating does not apply, and light-coloured parts require non-carbon-black formulations with antioxidant and UV packages.
Can AEM A70 be formed, bent or molded?
Compression, transfer or injection moulded at mould temperatures of 175–190 °C, followed by 4 h post-cure at 175 °C to stabilise compression set. Diamine cure systems need good venting and mould release.
What is the maximum service temperature of AEM A70?
AEM A70 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
- Vamac Ethylene Acrylic Elastomer product & compounding guides — DuPont / Dow Performance Elastomers (2020)
- ASM Engineered Materials Handbook Vol.2: Engineering Plastics & Elastomers — ASM International (1988)
- ASTM D2000 — Classification for Rubber Products in Automotive Applications (type EE/EF) — ASTM (2018)
- ASTM D412 / D624 / D395 / D2240 test methods for vulcanized rubber — ASTM (2021)
- Rubber Technologist's Handbook — Smithers Rapra (2009)
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.