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HIGHLY SATURATED NITRILE

DESCRIPTION

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.

COMPOSITION
Formed by hydrogenating the nitrile copolymer of butadiene and acrylonitrile. Medium density

PHYSICAL PROPERTIES* Excellent Good Fair Poor
Abrasion resistance    
Compression Set      
Elongation      
Flame resistance      
Gas permeability      
Low temperature flexibility        
Tear resistance      
Tensile strength      

CHEMICAL RESISTANCE* Excellent Good Fair Poor
Automatic transmission fluid      
Automotive refrigerants      
Oxygenated fuels      
Ozone    
Petroleum oils      
Sour crude oil      
Weather    

OPERATING TEMPERATURE
-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.