Buna-N Nitril O RINGS
Buna O-rings, NBR or Nitrile O-rings offer excellent sealing properties and mechanical properties with low cost. Buna and Nitrile O-rings have a basic resistance to common lubricants and are recommended for crude oil, gasoline, propane, petroleum oils and water. Nitrile and Buna O-rings are used in engines, gearboxes, aircraft pumps, and common water applications.
Nitrile Buna-N NBR O-Rings are used as a face-to-face or shaft seals, and allow rotary and linear movement. Nitrile O-rings have good tear and abrasion resistance with operating temperature: -30° to +250F° (can be increased to higher temperature sealing in special compounds).
Note: Nitrile / Buna / NBR o-rings do have limitations to ozone, sunlight and weathering. They are also not good in strong acids, aircraft or automobile brake systems, or ketones.
Advantages
• Good resitance to Petroleum greases, mineral oils, vegetable oils
• Good chemical compatibility and resistance
• Good abrasion and wear resistance
• Good compression set resistance
• Good Permeation Resistance
• Good oil resistance., etc
Application
• Dilute acids, alkali and salt solutions at low temperature
• Petroleum base oils and fluids, mineral oils,
• Silicone greases, di-ester base lubricants
• HFA, HFB and HFC hydraulic fluids
• Ethylene glycol base fluids
• Chemical resistace
• Water., etc
NBR Properties
|
Item |
NBR |
Test Method |
|
Color |
Black |
|
|
Specific gravity |
1.35/cm3 |
ASTM D297 |
|
Hardness |
40°-95° Shore A |
ASTM D2240 |
|
Tensile strength |
9 MPa (min) |
ASTM D412 |
|
Elongation at break |
350% (min) |
ASTM D412 |
|
Size |
Varies |
|
|
Compression set 100°C 22 hrs |
13-25% |
ASTM D 395B |
|
Tear resistance |
25 kg/cm (min) |
ASTM D624 |
|
Temperature range |
-25°C to +120°C |
|
Kinds of Rubber Properties
|
Common name |
Neoprene |
EPDM |
Nitrile |
Silicone |
Viton |
Kalrez |
|
Chemical Compatibility |
||||||
| Lubricating and Fuel Oils |
|
X |
|
X |
|
|
| Hydraulic Oils |
|
X |
|
|
|
|
| Fireproof Hydraulic Fluids |
|
|
|
|
X |
|
| Vegetable Oils, Animal Fats |
|
|
|
|
|
|
| Gasoline (high octane) |
 X
|
X |
 
|
X |
|
|
| Kerosene |
|
X |
|
X |
|
|
| Aromatic Hydrocarbons | X | X |
X
|
X |
|
|
| Aliphatic Hydrocarbons |
|
X |
|
X |
|
|
| Alcohols |
|
|
|
|
|
|
| Ketones |
X
|
|
X | X | X |
|
| Halogenated Solvents | X | X | X | X |
|
|
| Water (>80°C) |
|
|
|
|
|
|
| Concentrated Acids | X | X | X | X |
|
|
| Diluted Acids |
|
|
X
|
X |
|
|
| Alkalis |
|
|
|
|
X |
|
|
Properties |
||||||
| Max. Continuous temp °C | 105 | 150 | 121 | 204 | 204 | 316 |
| Low Temperature °C | –50 | –54 | –25 | –85 to –125 | –8 to -30 | –8 |
| Tensile Strength, MPa | 25 | 17 | 27 | 10 | 20 | 15 |
| Hardness Shore A | 30–95 | 40–90 | 40–95 | 30–90 | 55–95 | 65-95 |
Key: = Excellent , = Good, = Fair, X = Not Recommended
