Nitrile / NBR

NBR Nitrile

NBR (Nitrile), chemically, is a copolymer of butadiene and acrylonitrile. Acrylonitrile content varies in commercial products from 18% to 50%. As the NBR content increases, resistance to petroleum base oils and hydrocarbon fuels increases, but low temperature flexibility decreases. 

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About NBR

Due to its excellent resistance to petroleum products, and its ability to be compounded for service over a temperature range of -35°C to +120°C (-30°F to +250°F), Nitrile /NBR is the most widely used elastomer in the seal industry today. Also many military rubber specifications for fuel and oil resistant O-rings require nitrile based compounds.

It should be mentioned that to obtain good resistance to low temperature, it is often necessary to sacrifice some high temperature resistance. Nitrile compounds are superior to most elastomers with regard to compression set, tear, and abrasion resistance. Nitrile compounds do not possess good resistance to ozone, sunlight, or weather. They should not be stored near electric motors or other ozone generating equipment. 

NBR applications

NBR parts should be kept from direct sunlight. However, this can be improved through compounding. NBR is the standard material for hydraulics and pneumatics. NBR resists oil-based hydraulic fluids, fats, animal and vegetable oils, flame retardant liquids (HFA, HFB, HFC), grease, water, and air. Special low-temperature compounds are available for mineral oil-based fluids. By hydrogenation, carboxylic acid addition, or PVC blending, the nitrile polymer can meet a more specified range of physical or chemical requirements. The quality of Nitrile-compounds depends on the percentage of acrylonitrile in the base polymer.

Datasheets NBR

The table below shows the available datasheets for this material in pdf. Safety datasheets are available here.

Ask ERIKS

For more information on Nitrile / NBR or one of our other o-ring materials please contact one of the ERIKS Sealing & Polymer locations or fill in the form below.

NBR O-rings are made of acrylonitrile and butadiene, Buna N, Nitrile Rubber and NBR. The acrylonitrile content of NBR compounds varies considerably (18% to 50%) and influences the physical properties of the finished material.

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The higher the acrylonitrile content, the better the resistance to oil and fuel. At the same time, elasticity and compression set resistance to low temperature is adversely affected. The lower acrylonitrile content obtains, the better low temperature resistance, but at a sacrifice to some resistance to oils and fuels. In view of these opposing realities, a compromise selection is the medium acrylonitrile content rubber. NBR has good mechanical properties when compared with other elastomers and high wear resistance.

NBR is not resistant to weathering and ozone. Some special compounding can improve this defect by the use of a NBR/PVC blending compound which has excellent weathering and ozone resistance and good resistant to fuel but compression set is not good.

Service Temperature: For NBR the service temperature can be designed from -55 C to 100 C or up to 125 C depending on different acrylonitrile content and formula. Generally higher than 100 C, life time will be shortened.

Hardness: 40 to 90 Shore A are available.

Color: Black, brown, green, white, rust, yellow, blue, red, orange, and gray are available, or any assigned color from customers.

Application: NBR O-rings have excellent resistance to abrasion, non-polar oils and solvent, water and permeation (higher acrylonitrile content will be better). NBR also can be used in conditions of dilute acids, alkalis and salt solution at low temperatures. Applications in aromatic hydrocarbons, chlorinated hydrocarbons and polar solvents are not suitable.

Contact us to discuss your requirements of NBR O Ring. Our experienced sales team can help you identify the options that best suit your needs.