Oil resistance is a crucial characteristic of rubber materials. Rubber gaskets are frequently used in various oily environments, making oil resistance a vital parameter. However, the oil resistance varies among different rubber materials, as detailed below.
Fuel Resistance
Fluororubber (FKM) and fluorosilicone rubber (FMVQ) exhibit the best resistance to fuel oils. Chloroprene rubber and chlorinated polyethylene rubber (CPE) show the worst resistance. The fuel resistance of nitrile rubber increases with increasing acrylonitrile content. Chlorohydrin rubber has better fuel resistance than nitrile rubber.
Mixed Fuel Resistance
Fluorosilicone rubber (FMVQ) and fluororubber (FKM) demonstrate the best resistance to mixed fuel oils. Acrylic rubber exhibits the worst resistance to mixed fuel oils. The mixed fuel resistance of nitrile rubber increases with increasing acrylonitrile content. Fluororubbers with high fluorine content show better stability against mixed fuels.
Resistance to Acidic Oxidizing Fuels
For acidic oxidizing fuels, the hydroperoxides in these fuels can degrade the performance of vulcanized rubber. Therefore, nitrile rubber and chlorohydrin rubber commonly used in fuel systems are insufficient for long-term use.
Only fluorinated elastomers such as fluororubber FKM, fluorosilicone rubber FMVQ, fluorinated phosphonium nitrile rubber, and hydrogenated nitrile rubber exhibit better performance.
Ordinary nitrile rubber compounds cannot operate for extended periods in acidic gasoline at 125 degrees Celsius. Only nitrile rubber using cadmium oxide-activated low-sulfur donors and silica as primary raw materials can provide good resistance to acidic gasoline. Increasing the acrylonitrile content can reduce the permeability of acidic gasoline.