Rubber Seal material

Materials used as auxiliary sealing rings include rubber, plastic, asbestos, expanded graphite, graphite and metal expansion rings. Rubber ring is the most widely used auxiliary sealing ring. Commonly used rubber sealing ring materials include nitrile rubber, fluorine rubber, silicone rubber, neoprene rubber, styrene-butadiene rubber, etc.

Nitrile rubber is a commonly used oil-resistant rubber. It is a copolymer of butadiene and acrylonitrile. According to the acrylonitrile content, it is divided into several types: low acrylonitrile (butyronitrile-18), medium acrylonitrile (butyronitrile-26) and high acrylonitrile (butyronitrile-40). The higher the acrylonitrile content, the better its oil resistance. Good, the tensile strength, hardness, wear resistance, and water resistance increase, and the breathability decreases. Subsequently, its solubility in polar solvents increases, its corrosion resistance is also affected, and its elasticity and cold resistance also become worse. Nitrile rubber is not resistant to flexing and has poor tear resistance.

Fluorine rubber has the advantages of high temperature resistance, oil resistance and chemical corrosion resistance. The most widely used fluorine rubber is fluorine-containing olefin copolymer, mainly types 26 and 23. Type 26 includes fluororubber-26 series emulsion copolymer of vinylidene fluoride and hexafluoropropylene and fluororubber-246 series terpolymer of vinylidene fluoride, hexafluoropropylene and tetrafluoropropylene. Type 23 fluorine rubber is an amorphous rubber-like copolymer produced by suspension polymerization of vinylidene fluoride and chlorotrifluoroethylene at room temperature and 3.24MPa pressure. It cannot be used in liquid ammonia or ammonia water.

Silicone rubber is a polar polymer polymerized by dimethylsiloxane and other silicone monomers in the presence of acid or alkaline catalysts. Silicone rubber has high thermal stability, but it is polar and prone to ionic cracking under the action of acids and alkalis. Therefore, it has poor corrosion resistance and is not suitable for petroleum solvents (such as benzene, toluene, etc.), acetone, and ketone. Organic solvents such as ether.

PTFE has excellent chemical stability, oil resistance, solvent resistance, aging resistance, and temperature resistance. It also has a very low friction factor and certain strength, elasticity, flexibility, and non-adhesion. Therefore, it is widely used in various temperature applications. , sealing rings under pressure and corrosive media conditions.