Full definition
Acrylonitrile-butadiene copolymer — the standard elastomer for resistance to mineral oils, fuels, greases, and hydraulic fluids, making it the world's most widely used sealing material. The key formulation variable is acrylonitrile (ACN) content: low ACN (18-24%) gives best low-temperature flexibility (to -40°C) but lower oil resistance; medium ACN (28-36%) is the most common general-purpose grade; high ACN (38-50%) provides maximum oil resistance but poor cold flexibility. Properties: hardness 40-90 Shore A, tensile 10-25 MPa (with carbon black), elongation 200-600%, good abrasion resistance. ASTM D2000 classification: BF (low ACN), BG (medium), BK (high). Temperature range: -40 to +100°C (standard, +120°C intermittent). Limitations: poor ozone and UV resistance (requires antiozonant or blending with PVC), not resistant to polar solvents (ketones, esters, chlorinated solvents), nor strong acids. Applications: O-rings (the most specified material), oil seals, fuel hoses, hydraulic seals and packings, gaskets, nitrile examination gloves, printing press rollers, and flexible couplings. Also available as NBR/PVC blend (improved ozone resistance) and carboxylated XNBR (higher abrasion and tensile). Global production: ~800,000 tonnes/year.