Nitrile is one of the most common materials used in the industry today. Nitrile, frequently known as NBR or Buna-N, is a rubber compound that maintains a low cost while withstanding water, oils, lubricants, and some fuels, as well as an extensive temperature range.
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Nitrile is a synthetic copolymer of acrylonitrile and butadiene. Different properties can be observed by changing the acrylonitrile content in the formulation, ranging from 18% to 50%. Higher acrylonitrile content will cause higher oil and fuel resistance but lower temperature flexibility and compression set. Conversely, a lower acrylonitrile content will reduce the oil and fuel resistance but cause an increase in temperature flexibility and compression set. An acrylonitrile content of 32% is considered standard.
Hydrogenated nitrile O-rings (HNBR) are another option when looking for a sealing solution in higher temperatures or with use in harsher environments. HNBR O-ring temperatures usually range from- 23ºF to 300ºF. In addition, HNBR is more resistant to oils and fuels, ozone, heat, and some harsh chemicals.
Nitrile O-rings can be produced by injection molding, compression molding, or by extrusion. Although a round O-ring is standard, NBR O-rings can be made into other cross-sections. These cross-sections are dependent on application. Contact Wyatt Seal for more details if you are looking for a more custom solution.
To work correctly, all nitrile O-rings must be lubricated based on the application and formulation, generally a form of oil, fuel, or water.
As one of the most common seals used in the industry, nitrile O-rings are suitable for various static and dynamic applications, are easy to produce even at the specialty level, and are cost-effective. The most common uses of nitrile O-rings are in hydraulics, pneumatics, and fuel, generally in automotive equipment, off-road equipment, some military applications, marine devices, and aircraft fuel systems.
Nitrile O-rings can be the correct sealing option for many applications due to the resistance to many oils, fuels, water, and lubricants, as well as the wide array of material properties. These properties include a low compression set, high tensile strength, high abrasion resistance, and low gas permeability. Standard durometer (hardness) can range from 40 Shore A to 90 Shore A.
Standard nitrile O-ring temperature ranges are from - 30ºF to 250ºF. However, different formulations can allow for lower or higher temperature ranges. These temperatures are based on dry air; the actual temperature range depends on end-use application and will vary.
The dimensions of nitrile O-rings you would need vary by application. Consult our O-ring size chart for details on our most common sizes so that you can order confidently, knowing you will receive a sealing solution that will arrive on time, perform well, and last.
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