What do you need to know about the sealing material of solenoid valve?

There are three most commonly used sealing materials for solenoid valves. Here are some introduction:

1、 nitrile butadiene rubber(NBR) 

Obtained from emulsion polymerization of butadiene and acrylonitrile, acrylonitrile butadiene rubber is mainly produced by low temperature emulsion polymerization. It 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 performance and low elasticity.

In addition, it has good water resistance, air tightness and excellent bonding performance. It is widely used in the manufacture of various oil resistant rubber products, various oil-resistant washers, gasket, sleeve, soft packaging, soft rubber tube, printing and dyeing rubber roller, cable rubber material, etc., which has become an indispensable elastic material in automobile, aviation, oil, copying and other industries.

NBR has excellent oil resistance, and its oil resistance is second to polysulfide rubber and fluororubber, and has the 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, and it is not suitable for insulating materials.

Main uses: NBR is mainly used for oil resistant products, such as oil resistant pipe, tape, rubber diaphragm and large oil bag, etc. it is often used to make various oil resistant molded products, such as O-ring, oil seal, leather bowl, diaphragm, valve, bellows, etc., and also used for rubber plate and wear-resistant parts.

2、 Ethylene-Propylene-Diene Monomer(EPDM)

EPDM is a terpolymer of ethylene, propylene and non conjugated diene. It began commercial production in 1963. The annual consumption of the world is 800000 tons. EPDM has the most important characteristics of its superior oxidation resistance, ozone resistance and erosion resistance. As EPDM belongs to polyolefin family, it has excellent vulcanization properties. Of all rubber, EPDM has the lowest specific gravity. It can absorb a large amount of filler and oil, and its influence on the properties is not large. Therefore, it can be used to produce rubber compounds with low cost.

Molecular structure and characteristics

Structure: EPDM is a ternary copolymer of ethylene, propylene and non conjugated diene. Diene has a special structure, only one of the two bonds can be copolymerized, and unsaturated double bonds are mainly used as the cross chain. Another unsaturated one will not be the main polymer chain, but only the side chain. The main polymer chain of EPDM is completely saturated. This property allows EPDM to resist heat, light, oxygen, especially ozone. EPDM is essentially non-polar, resistant to polar solutions and chemicals, low water absorption and good insulation.

Features: 1. Electrical performance; 2. Elasticity; 3. Adhesion; 4. Low density and high filling property; 5. The performance of the super hot water resistance; 6. Water vapor resistance; 7. Aging resistance; 8. Corrosion resistance.

3、 Viton fluororubber (FKM)

The rubber containing fluorine has various types according to the fluorine content, i.e. monomer structure; Currently, fluororubber with widely used hexafluoride system was listed by DuPont company as "Viton" commodity. The high temperature resistance is better than that of silicone rubber... Chemical resistance, most oil and solvents (except ketones and esters), weather resistance and ozone resistance are good, but cold resistance is poor; Generally, it is widely used in steam turbine, B and other products, and the sealing parts of chemical plants. The temperature range is -20 ℃ ~ 260 ℃, and the low temperature type can be used to -40 ℃ but the price is high.