Nitrile (NBR) is the most commonly specified polymer, acrylonitrile content varies from 18% to 50%. Resistance to petroleum products is enhanced with higher acrylonitrile content (High Nitrile), however this is at the cost of a decrease in the low temperature flexibility.  Reducing the acrylonitrile conent (Low Nitrile) extends the low temperature flexibility, but at the expense of reduced resistence to petroleum prodcuts.  Standard Nitrile compounds have a medium acrylonitrile content – these are generally known as ‘Medium Nitrile’. If the application demands higher or lower acrylonitrile content than medium more care must be taken choosing the right formulation.

Compounds based on Nitrile can exhibit excellent compression set, tear and abrasion resistance. They do not have good resistance to ozone, sunlight or weather (unless especially compounded). Consequently they should not be stored in direct sunlight, and should be kept away from sources of ozone (e.g. electric motors). Standard Medium Nitrile compounds can be used between -20°C and +125°C. Special formulations of Nitrile compound can extend the temperature range.

May be used for Should not be used for

Ethylene Glycol
Silicone Fluids
Petroleum Fluids
Water (to 100°C)

Brake fluids
Ozone or weathering
Phosphate esters
Strong acids