There are currently three most commonly used sealing materials for solenoid valves:
NBR (Nitrile Butadiene Rubber)
NBR is produced by emulsion polymerization of butadiene and acrylonitrile. It is mainly produced using low-temperature emulsion polymerization and has excellent oil resistance, high wear resistance, good heat resistance, and strong adhesion. Its disadvantages include poor low-temperature resistance, poor ozone resistance, poor electrical properties, and slightly lower elasticity.
EPDM (Ethylene Propylene Diene Monomer)
EPDM is a terpolymer of ethylene, propylene, and a non-conjugated diene. Commercial production began in 1963. Global consumption is 800,000 tons annually. EPDM's most important characteristics are its superior resistance to oxidation, ozone, and corrosion. As EPDM belongs to the polyolefin family, it has excellent vulcanization properties. Among all rubbers, EPDM has the lowest specific gravity. It can absorb large amounts of fillers and oils with minimal impact on its properties. Therefore, it can be used to produce low-cost rubber compounds.
VITON Fluororubber (FKM)
Fluororubbers containing fluorine in their molecules come in various types depending on the fluorine content and monomer structure. Hexafluorinated fluororubbers exhibit better high-temperature resistance than silicone rubber, and possess excellent chemical resistance, resistance to most oils and solvents (except ketones and esters), weather resistance, and ozone resistance, but poor cold-resistant properties. They are widely used in automotive, motorcycle, and chemical plant sealing components, with an operating temperature range of -20℃ to 260℃. For low-temperature applications, low-temperature resistant types are available that can operate down to -40℃, but these are more expensive.
