Orbn173 Standard O-Ring for Buna Nitrile Rubber

Buna N or Nitrile, a copolymer of butadiene and acrylonitrile, is the most widely used elastomer in the seal industry today. The acrylonitrile content in commercial products varies from 18% to 48%, and as the nitrile content increases, the resistance to petroleum base oils and hydrocarbon fuels increases, but the low-temperature flexibility decreases.

Nitrile is known for its excellent resistance to petroleum products and its ability to be compounded for service over a temperature range of -65 to + 275 degrees Fahrenheit (-54 to +135 degrees Celsius). Most military rubber specifications for fuel and oil-resistant MS and AN O-rings require nitrile base compounds. However, it should be noted that to obtain good resistance to low temperature with nitrile compounding, it is almost always necessary to sacrifice some high-temperature fuel and oil resistance.

Nitrile compounds are superior to most elastomers with regard to compression set or cold flow, tear, and abrasion resistance. While they inherently possess good resistance to ozone, sunlight, or weather, this can be substantially improved through compounding. Nevertheless, since ozone and weather resistance are not always built in, seals from nitrile bases should not be stored near electric motors or other equipment that may generate ozone, or in direct sunlight.

ORBN173 is a nitrile-based compound that is suitable for use across a wide temperature range from -30 degrees Fahrenheit (-34 degrees Celsius) to 250 degrees Fahrenheit (121 degrees Celsius). It offers good to excellent resistance to many petroleum oils/greases, hydraulic fluids, alcohol, mineral oil, and grease. This makes it suitable for oil-resistant applications of all types, including low-temperature military uses, off-road equipment, automotive, marine, and aircraft fuel systems. The compound has a 70 Durometer rating, indicating its good mechanical properties and high wear resistance.

Buna N or Nitrile is compatible with aliphatic hydrocarbons, such as propane, butane, petroleum oil, mineral oils, greases, diesel fuel, and fuel oil. However, it is not compatible with product fuels with a high aromatic content, aromatic hydrocarbons (benzene), or chlorinated hydrocarbons (Trichloroethylene).

In summary, Buna N or Nitrile is a versatile and widely used elastomer in the seal industry, offering excellent resistance to petroleum products and a wide temperature range of application. Its superior mechanical properties and compatibility with various fluids make it a popular choice for many industries, including military, automotive, marine, and off-road equipment.

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