Description of three kinds of sealing materials commonly used in solenoid valves

VITON fluororubber (FKM)
The fluorine-containing rubber in the molecule has various types depending on the fluorine content, that is, the monomer structure. Currently, the hexafluoride-based fluorocarbon rubber is first marketed by DuPont under the trade name "VITON". The high temperature resistance is superior to the silicone rubber. ... chemical resistance, resistance to most oils and solvents (except ketones and esters), good weather resistance and ozone resistance, but poor cold resistance; generally used in steam locomotives, B, etc., chemical plant seals Parts, the temperature range of -20 ° C ~ 260 ° C, low temperature requirements when used, low temperature type can be applied to -40 ° C, for higher prices.
NBR nitrile rubber (nitrile butadiene rubber )
Made of butadiene and acrylonitrile by emulsion polymerization, the nitrile rubber is mainly produced by low-temperature emulsion polymerization, which has excellent oil resistance, high wear resistance, good heat resistance and strong adhesion. The disadvantages are poor low temperature resistance, poor ozone resistance, poor electrical properties, and slightly lower elasticity.
In addition, it has good water resistance, air tightness and excellent bonding properties. Widely used in the manufacture of various oil-resistant rubber products, a variety of oil-resistant gaskets, gaskets, casings, flexible packaging, soft rubber hoses, printing and dyeing rubber rollers, cable rubber materials, etc., in the automotive, aviation, petroleum, copying and other industries become essential Elastic material.
Nitrile rubber has excellent oil resistance, its oil resistance is second only to polysulfide rubber and fluororubber, and it has wear resistance and air tightness. The disadvantage of NBR is that it is not resistant to ozone and aromatic, halogenated hydrocarbons, ketones and ester solvents. It is not suitable for insulating materials.
  The main purpose
Nitrile rubber is mainly used in the production of oil-resistant products, such as oil-resistant pipes, tapes, rubber diaphragms and large oil bladders. It is commonly used in the production of various oil-resistant molded products, such as O-rings, oil seals, cups, diaphragms, valves, bellows. Etc., also used to make rubber sheets and wear parts.
EPDM EPDM (Ethylene-Propylene-Diene Monomer)
EPDM rubber is a terpolymer of ethylene, propylene and non-conjugated diene, which was commercialized in 1963. The annual consumption worldwide is 800,000 tons. The most important feature of EPDM is its superior resistance to oxidation, ozone and erosion. Since EPDM is a polyolefin family, it has excellent vulcanization characteristics. Among all rubbers, EPDM has the lowest specific gravity. It absorbs a large amount of fillers and oils and has little effect on properties. Therefore, it is possible to produce a rubber compound which is inexpensive.
Molecular structure and properties
EPDM is a terpolymer of ethylene, propylene and a non-conjugated diene. Diolefins have a special structure, only one of the two bonds can be copolymerized, and the unsaturated double bonds are mainly used as a crosslink. Another unsaturation will not become the polymer backbone, it will only become a side chain. The main polymer chain of EPDM is fully saturated. This property makes EPDM resistant to heat, light, oxygen, and especially ozone. EPDM is essentially non-polar, resistant to polar solutions and chemicals, low in water absorption, and has good insulating properties.
Features:
1, low density and high filling; 2, aging resistance; 3, corrosion resistance; 4, water vapor resistance; 5, resistance to hot water; 6, electrical properties; 7, elasticity; 8, adhesion.