HIGHLY SATURATED NITRILE
Hydrogenation of nitrile rubber removes most of the residual unsaturation in the polymer backbone to make it far less vulnerable to attack by heat, ozone and oxygen. In fact, due to superior oil and temperature resistance, highly saturated nitrile can sometimes be substituted for costlier fluorocarbon rubber. It is frequently used in automotive air conditioning systems employing R-134a and R-1234yf refrigerants. HNBR can be either peroxide- or sulfur-cured, depending on the degree of unsaturation achieved by the hydrogenation process, but peroxide is almost always used due to the good heat stability properties of the peroxide crosslinks. It can be compounded for both low and high temperature use. RT Dygert’s compound N-7003, a 70 durometer green HNBR, has been tested and found to be exceptionally compatible with both R-134a and R-1234yf, and the associated lubricating oils used with them.
|Formed by hydrogenating the nitrile copolymer of butadiene and acrylonitrile. Medium density|
|Low temperature flexibility||•|
|Automatic transmission fluid||•|
|Sour crude oil||•|
|-25 to 300 °F|
*Excellent, good, fair and poor are intended to serve as general guidelines only. Actual testing in the application environment is always recommended.