311 – Polyacrylate rubber (ACM)

ASTM D-2000 classification: CF, DF, DH, EH


Temperature Range:

Low Temp:    -20°C (-5°F)            Brittle -25°C (-13°F)

High Temp:   150°C (300°F)         Intermittent 180°C (356°F)



Polyacrylate rubber (or ACM) is a specialty rubber with the primary advantage being its ability to withstand high heat while retaining oil resistance. It is often used for applications involving sulphur bearing lubricants, which are experiencing increased usage in automotive applications, particularly transmission seals.

From the standpoint of performance, ACM occupies an intermediate position between fluorocarbon and nitrile. Additionally, polyacrylates are not highly corrosive to steel, exhibit good damping characteristics and can be compounded to provide excellent flex life and some degree of flame resistance. However, this acrylic based elastomer has a few limitations. The poor low temperature flexibility lessens its usefulness, and its compression set is not as good as that of most other compounds. It is also not as good as many other elastomers in strength and water resistance.



ACM is mainly used for O-rings and shaft seals to seal heavy oils at high temperatures and in the automotive industry for transmission and power steering applications.


EMI ReferenceSpecificationHardness IRHDSGTensile Strength (MPa)Elongation at Break %Colour
311 - 40 Good Commercial40°1.117400Black
311 - 50Good Commercial50°1.117375Black
311 - 60Good Commercial60°1.118350Black
311 - 70 Good Commercial70°1.118350Black
311 - 80 Good Commercial80°1.119325Black
311 - 90 Good Commercial90°1.120300Black

Full data sheets for all grades are available on request.

* The information above is supplied in good faith and believed to be correct. This information is supplied upon the condition that persons receiving this will make their own determination as to its suitability for their purposes prior to use. EMI makes no representations or warranties, either expressed or implied with respect to the information or the product to which this information refers.