ACM Acrylic Rubber Compound

When NBR starts to harden and crack at 150°C, ACM — polyacrylate rubber — holds its shape, its seals, and your customer’s trust. Designed for the demanding thermal environments inside modern powertrains, this acrylic rubber compound delivers exceptional oil resistance at sustained temperatures where nitrile compounds simply fail — without the cost of a full…

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Specifications

Product Type：
Custom Rubber Compound / Molded or Extruded Parts

Base Polymer：
ACM (Acrylate Rubber / Polyacrylate Rubber, Polyacrylic Rubber)

Structure：
Solid

Color: 
Black standard; custom colors available on request

Surface Finish：
Smooth; matte or textured per customer tooling

Standards & Compliance: 

Hardness:
50–80 Shore A (standard: 60 ± 5 Shore A)

Tensile Strength: 
≥ 18 kN/m

Elongation at Break:
≥ 180%

Tear Strength:
≥ 18 kN/m

Recommended Service Temperature:
-25°C to +175°C (short excursions to +190°C)

Hot Air Aging:
175°C × 70h: Hardness change ≤ +10 Shore A; Tensile retention ≥ 65%

Low‑Temperature Brittleness: 
≤ -25°C (TR10 method); enhanced cold grades available

Typical Applications:
Automatic transmission seals, crankshaft rear oil seals, power steering hose, turbocharger oil return hose, high-temp gaskets

Description：

Most engineers reach for NBR first. It’s proven, it’s available everywhere, and at ambient and moderate temperatures it performs well in oil. The problem shows up around the 140–150°C range: NBR’s unsaturated backbone starts to oxidize in the presence of hot transmission fluid or engine oil, and hardness climbs fast. Seals stiffen, lose compliance, and leak. The obvious alternative — FKM (Viton) — solves the temperature problem decisively, but at two to three times the compound cost and with processing constraints that add tooling complexity.ACM sits directly in that gap. Its polyacrylate backbone is almost fully saturated, which means it resists the oxidative attack that degrades NBR in hot oil environments. Service temperatures to +175°C are routine; with appropriate formulation selection, short excursions to +190°C are manageable. The payoff: oil-resistance performance that genuinely competes with lower-grade FKM, at a material cost substantially below fluoro-elastomers.This is not a universal material. ACM has real limitations — it absorbs water, it performs poorly in water-glycol brake fluids, and its low-temperature flexibility is inferior to EPDM or NBR. Engineers who understand where ACM belongs use it very precisely: automatic transmission seals, crankshaft seals, power steering hose, and high-temperature gaskets in oil-wetted environments. That precision is exactly where Micune’s compounding expertise adds value.

Typical Industry Applications：

Proven performance across demanding manufacturing environments.

Industry Typical Use Cases
Automotive & Powertrain Automatic transmission shaft seals, crankshaft rear oil seals, differential seals, power steering hose inner liner, turbocharger oil return hose, valve stem seals
Commercial Vehicle & Motorcycle Gearbox lip seals, hydraulic clutch hose, engine oil cooler hose joints
Industrial Machinery High-temperature oil-circuit gaskets, shaft seals for gearboxes and compressors, pump seal elements
Agricultural & Off-Highway Equipment Transmission seals, hydraulic control valve seals in high-temp operating environments
Specialty Hydraulics Oil-resistant sealing elements where service temperature exceeds NBR capability but FKM is cost-prohibitive

Chemical Resistance Table：

Chemical / Medium Resistance Notes
Mineral Engine Oil (SAE 5W-30 to 20W-50) ✅ Excellent Primary design environment for ACM
Automatic Transmission Fluid (ATF) ✅ Excellent At 150°C; volume swell ≤ 15%
Gear Oil (API GL-4/GL-5) ✅ Excellent Good resistance; verify with specific formulation
Power Steering Fluid (mineral-based) ✅ Excellent Standard application for ACM hose grades
Hydraulic Oil (mineral, HM-type) ✓ Good Functional across standard industrial grades
Greases (lithium, calcium soap-based) ✓ Good Generally compatible at elevated temperature
Dilute Oxidized Fuel (hot blow-by gas) ✓ Good Better than NBR under high-temperature oxidizing conditions
Aliphatic Hydrocarbons ✓ Good Gasoline contact: limited swell, check compound grade
Hot Air / Ozone ✅ Excellent Saturated backbone; superior to NR and SBR
Ethylene Glycol Coolant ⚠ Limited Moderate exposure only; ACM absorbs polar liquids
Water / Steam ⚠ Limited ACM swells in water; not suitable for prolonged immersion
Brake Fluid (DOT 3/4, glycol-based) ✗ Not recommended ACM degraded by glycol chemistry
Methanol / Ethanol (neat) ✗ Not recommended Rapid absorption and swelling
Ketones / Esters ✗ Not recommended Incompatible solvents

In-House Quality Assurance & Testing:

At Micune Rubber, batch-to-batch consistency is guaranteed through our ISO-9001 certified Quality Management System. Every rubber compound and custom extrusion undergoes rigorous evaluation in our dedicated testing laboratory before shipment. We utilise industry-standard baseline testing, including Mooney Viscometers to measure compound viscosity and Torque Rheometers to verify exact vulcanisation characteristics. This ensures every material formulation strictly adheres to your required specifications and processing parameters.

Mooney Viscometer

Mooney Viscometer

abrasive testing machine

Abrasive Testing Machine

Burn-in Chamber

Burn-in Chamber

Torque Rheometer

Torque-Rheometer

RFQ：

Standard ACM compound grades run from 50 to 80 Shore A, with 60 ± 5 Shore A being the most common selection for static and dynamic lip seals. Softer grades down to 45 Shore A are achievable with formulation adjustment, though very soft ACM can show higher compression set — an important trade-off to discuss before finalizing design parameters. Please share your compression force target, bore diameter, and operating temperature range when inquiring.

Yes — active ACM grades are tested by SGS against EU RoHS Directive (EU) 2015/863 for restricted substances and AfPS GS 2019:01 for PAHs, with all restricted substances confirmed as Not Detected (ND). Third-party SGS test reports with verifiable report numbers are available for customer review prior to order. If your application requires specific customer-mandated test protocols (e.g., IMDS submission for automotive supply chains), notify us at inquiry stage and we will confirm which documentation package applies.

Micune’s formulation library includes multiple ACM cure-site variants — active-chlorine, epoxy, and carboxyl grades — each with different low-temperature and fluid-compatibility profiles. The standard grade is rated to -25°C brittleness; improved low-temperature grades targeting -30°C are available at the cost of some reduction in heat aging retention. For OEM fluid compatibility (e.g., specific ATF brands or proprietary hydraulic fluids), provide the fluid specification or SDS and the target immersion test conditions, and our R&D team will identify the appropriate grade or develop a qualification protocol.

For parts requiring existing mold configurations close to your profile, first article samples typically ship within 15–20 business days from approved drawing. Custom tooling — new molds for a unique seal geometry — adds 20–30 days for mold fabrication prior to first shot. Sample quantities are 10–50 pieces as standard for initial validation, with dimensional report and material test coupon data included. Expedited timelines can be arranged for critical programs; contact us with your drawing and target milestone.

Minimum order quantity for finished ACM molded or extruded parts is typically 500–2,000 pieces per part number depending on complexity, with lower MOQs available for sample-to-production bridge orders. For ACM rubber compound supplied as mixed, uncured stock, the MOQ is 100 kg. Ongoing supply agreements with fixed quarterly call-offs are supported, and Micune maintains safety stock for active programs under agreed terms. Lead times for repeat orders on established part numbers run 15–25 business days ex-works Guangzhou.

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