NBR (Nitrile Butadiene Rubber)
cao su nitrile
Also known as: nitrile rubber · Buna-N · acrylonitrile butadiene rubber
NBR (Nitrile Butadiene Rubber) is the most widely used O-ring and gasket elastomer, offering excellent resistance to petroleum oils, fuels, and hydraulic fluids from –40°C to +120°C.
Technical Detail
NBR is a synthetic copolymer of acrylonitrile (ACN) and butadiene. ACN content ranges from 18% (better low-temp flexibility) to 50% (better oil resistance). Standard O-ring compound is 33–34% ACN, 70 Shore A hardness. Key properties: excellent resistance to mineral oils, diesel, gasoline, hydraulic fluid (HLP), and greases; poor resistance to aromatic solvents (toluene, MEK), ozone, UV, and steam above 100°C. Temperature range: –40°C to +120°C continuous, short spikes to +135°C. Compression set: ≤25% at 100°C/70h (ASTM D395B) for quality compounds. NBR is the default choice for hydraulic cylinder seals, pneumatic O-rings, fuel system gaskets, and general industrial sealing. Specify HNBR (hydrogenated NBR) for improved heat and ozone resistance to +150°C at higher cost.
Reference Standards
- ASTM D2000 BA/BF grade
- ISO 1629
- DIN 53505
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