ACM (Acrylic Rubber): High-Temperature Oil-Resistant Elastomer
Acrylic Rubber (ACM) is a specialty synthetic elastomer engineered for exceptional resistance to hot oils, oxidation, and elevated temperatures. Widely specified in automotive transmission and powertrain applications, ACM delivers reliable sealing performance in hot lubricant environments where standard oil-resistant elastomers like NBR fail due to heat degradation.
Key Properties of ACM Rubber
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Superior Hot Oil Resistance: Excellent resistance to hot mineral oils, ATF (automatic transmission fluid), and engine oils at elevated temperatures
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High Temperature Performance: Continuous operation from -15°F to 350°F (-26°C to 177°C)
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Oxidation Resistance: Outstanding resistance to heat aging and oxidative degradation
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Low Compression Set: Excellent resistance to permanent deformation at high temperatures
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Weather Resistance: Good UV, ozone, and outdoor aging resistance
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Flex Fatigue Resistance: Good resistance to dynamic flexing in hot oil environments
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Sulfur Resistance: Compatible with sulfur-containing lubricants and additives
Common Applications & Uses
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Automotive Hoses: Many automotive hoses especially on cold side intercoolers use either ACM as liner for silicone rubber hoses or use ACM rubber for the entire hose.
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Automotive Transmission: Transmission seals, O-rings, gaskets for automatic transmissions
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Powertrain: Crankshaft seals, valve stem seals, oil pan gaskets
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Engine Components: Timing cover seals, oil pump seals, turbocharger gaskets
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Industrial: Hot oil seals, hydraulic seals for high-temperature fluids
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Power Steering: Seals and hoses for power steering systems
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Lubrication Systems: Seals and gaskets for hot lubricant applications
Advantages of ACM
- Superior hot oil resistance—outperforms NBR at temperatures above 250°F
- Excellent heat aging and oxidation resistance for long service life
- Low compression set at elevated temperatures maintains sealing integrity
- Good weather and ozone resistance for outdoor exposure
- Compatible with sulfur-containing lubricants and extreme pressure additives
- Maintains flexibility and sealing performance in hot transmission fluids
- Cost-effective alternative to fluoroelastomers (FKM) for hot oil applications
- Good resistance to flex fatigue in dynamic sealing applications
Limitations & Disadvantages
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Poor Low-Temperature Flexibility: Limited flexibility below -15°F—not suitable for cold environments
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Water & Steam Sensitivity: Poor resistance to water, steam, and glycol-based fluids
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Limited Fuel Resistance: Not suitable for gasoline or aromatic fuels—NBR or FKM preferred
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Polar Solvent Incompatibility: Poor resistance to ketones, esters, and chlorinated solvents
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Processing Challenges: Requires careful curing and post-cure for optimal properties
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Higher Cost: More expensive than NBR, though less costly than FKM
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Acid Sensitivity: Limited resistance to strong acids compared to FKM
ACM vs. Other Rubber Materials
ACM vs. NBR (Nitrile): ACM offers superior hot oil resistance and heat aging above 250°F, while NBR provides better low-temperature flexibility and lower cost. Use ACM for hot transmission and engine oil seals; NBR for standard-temperature petroleum applications.
ACM vs. FKM (Viton): FKM offers broader chemical resistance and higher temperature capability (400°F vs. 350°F), but ACM is more cost-effective for dedicated hot oil applications. ACM is the choice for transmission seals; FKM for multi-chemical, extreme-temperature environments.
ACM vs. HNBR (Hydrogenated Nitrile): HNBR provides better low-temperature flexibility (-40°F) and broader chemical resistance, while ACM offers superior hot oil resistance and lower cost. ACM is preferred for hot transmission fluids; HNBR for wider temperature range oil applications.
ACM vs. Silicone: Silicone offers wider temperature range (-65°F to 450°F) but poor oil resistance. ACM provides superior hot oil resistance with good high-temperature performance. ACM is the choice for hot oil sealing; silicone for extreme temperatures without oil contact.
ACM vs. EPDM: EPDM excels in weather, water, and steam resistance, while ACM is superior for hot oil applications. EPDM is incompatible with petroleum oils; ACM is designed specifically for hot lubricant environments.
ACM Grades & Types
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Standard ACM: General-purpose grade for transmission and hot oil seals—most common type
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Carboxylated ACM: Enhanced heat resistance and compression set performance
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Chlorine-containing ACM: Improved oil resistance and processing characteristics
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Low-temperature ACM: Modified formulations for improved cold flexibility (down to -25°F)
Curing & Processing Considerations
ACM requires specialized curing systems (typically amine or soap cures) and often benefits from post-cure heat treatment to achieve optimal hot oil resistance and compression set properties. Proper curing is critical for long-term performance in high-temperature applications.
Technical Specifications
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Hardness Range: 60–90 Shore A (customizable by formulation)
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Specific Gravity: 1.05–1.10
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Tensile Strength: 1,000–2,000 psi (varies by grade)
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Elongation at Break: 150–400% (varies by formulation)
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Compression Set: Excellent at elevated temperatures (typically <25% at 150°C/302°F for 70 hours)
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Temperature Range: -15°F to 350°F continuous (-26°C to 177°C)
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Volume Swell in Oil: Low swell in hot ATF and engine oils
Why Choose ACM from Rubber Mexico?
Our ACM compounds are formulated for maximum hot oil resistance, heat aging stability, and compression set performance across automotive transmission, powertrain, and industrial lubrication applications. With in-house molding, precision machining, and custom compounding capabilities, we deliver mission-critical ACM seals and gaskets engineered to your exact specifications and operating temperatures.
Need a custom ACM solution? Contact us for material selection guidance, grade optimization, post-cure development, compound testing, prototyping, and production support for your hot oil sealing challenges.
