Nitrile Rubber (NBR) Selection and Procurement: The Specialist Elastomer for Oil-Resistant Seals and Hoses

Nitrile rubber (NBR) is a copolymer of butadiene and acrylonitrile (ACN). Thanks to its polar acrylonitrile segments, it delivers outstanding oil, fuel and solvent resistance, making it an irreplaceable oil-resistant elastomer in petroleum, automotive, hydraulic and appliance sectors.

ACN Content: Balancing Oil Resistance and Cold Resistance

The higher the acrylonitrile content, the better the oil and solvent resistance, but the lower the cold resistance and elasticity. Low-ACN grades are softer and better at low temperatures but weaker in oil resistance. Selection is essentially a balance between oil resistance and cold resistance according to the medium (mineral oil / fuel / polar solvents) and working temperature. Medium-to-high ACN grades are commonly used for engine oil and gear oil.

Typical Applications

Oil seals and sealing parts: static and dynamic sealing in engines, transmissions and hydraulic systems; oil-resistant hoses: inner layers of fuel lines and hydraulic hoses; industrial products: rollers, gaskets and conveyor belts. It is often listed alongside SBR, BR and EPDM as a general-purpose synthetic rubber, but NBR's irreplaceability comes from its oil resistance.

Procurement and Selection Points

Once the working medium and temperature are defined, lock down the ACN content range, Mooney viscosity (processability), Mooney scorch and volatile matter. For higher weatherability, consider hydrogenated nitrile rubber (HNBR). We recommend requesting a COA and running a media immersion swelling test (volume change rate). Haiyu Zhonglong provides stable supply and selection support for NBR and other synthetic rubbers. Submit an Online Inquiry or Contact Us; see more in the Product Centre.