Rubber seals use different rubber materials because of different requirements of environment and occasion. Rubber oil seals are made of nitrile rubber, hydrogenated nitrile rubber, acrylate rubber and fluororubber, fluorosilicone rubber, perfluororubber and other sealing materials.

1. NBR

Nitrile-butadiene rubber (NBR) is the most commonly used material in the production of seals.

Nitrile-butadiene rubber (NBR) has excellent properties such as fuel oil resistance and aromatic solvents. It can meet the general requirements and has low cost.

2. Natural Rubber

Compared with most synthetic rubber, natural rubber has good comprehensive mechanical properties, cold resistance, high resilience and wear resistance. Natural rubber is not resistant to mineral oil, but is stable in vegetable oil and alcohols.

III. Acrylate Rubber

Acrylate rubber has excellent comprehensive properties of heat and oil resistance. It can be used as high as 180 - 200 C. It is widely used in products requiring high temperature and heat-resistant oil.

Acrylate rubber is called automotive rubber. It is the suitable material for making rubber oil seals, O-rings, gaskets and rubber hoses used at high temperature. It is also an important material in automobile industry.

Acrylate rubber also has many other excellent properties, such as ozone resistance, flexibility resistance, sunlight aging resistance, good air tightness, transparency of rubber and good adhesion of fabric.

Acrylic rubber has a wide range of applications - sponge products, deep well exploration, electrical industry to replace some of the silicone rubber, adhesives.

IV. Fluororubber

1. Fluororubber is a synthetic polymer elastomer containing fluorine atoms on the carbon atoms of the main or side chains

Advantages of Fluororubber

Among the rubber sealing materials, its heat resistance (decomposition temperature is more than 400 degrees Celsius), oil resistance (all kinds of fuel oil, hydraulic oil, lubricating oil, synthetic oil), solvent resistance, climate resistance (other line resistance, ozone resistance, radiation resistance), chemical medium resistance are the best, all surface nitrile rubber, polyurethane rubber can not be used in high temperature environment. Fluorine rubber can be used as sealing material in lower or special working fluids. It has good physical and mechanical properties. It has the best comprehensive strength among all synthetic rubber. It is commonly known as "Rubber King" and has become an indispensable and substitutable base in modern industry, especially in high-tech fields. One of the basic materials.

Defects of Fluororubber

Its processing performance is not easy to grasp, and its price is high. It is 20 times as gorgeous as nitrile rubber. Its cold resistance, water resistance and elasticity at room temperature are poor. Fluorine rubber products with improved cold resistance and water resistance have been developed on the market. In addition, FFKM with better resistance and drug resistance is better than ordinary fluorine rubber, but its price is lower than fluorine rubber. The rubber is 10 times as high.

Application of Fluororubber Seals

Fluororubber is widely used in national defense, military industry, automobile, aviation, aerospace and petroleum fields. Fluororubber oil seals are also used in drilling machinery, oil refining equipment and natural gas desulfurization equipment. They can withstand harsh conditions such as high temperature, high pressure oil and strong corrosive media. Fluororubber oil seals are used in pumps and pipe joints in chemical field. Head, equipment containers, used to seal inorganic acids, such as chemical substances; in the military industry, fluororubber is mainly used in aerospace, aviation and carrier rockets, satellites, fighter planes, new tank oil seals, oil pipes and electrical circuit sheaths, etc., is one of the key sealing materials that can not be replaced in the advanced industry of national defense.

V. Hydrogenated NBR

Hydrogenated nitrile-butadiene rubber is a synthetic polymer, which saturates the hydrocarbon chain of nitrile-butadiene rubber by hydrogenation reaction. This special hydrogenation process reduces the double bonds on the main chain of many nitrile-butadiene rubber (NBR) polymers. Therefore, the hydrogenated nitrile-butadiene rubber has higher degree than the original nitrile-butadiene rubber besides retaining the characteristics of the original nitrile-butadiene rubber. Properties and mechanical properties of heat resistance, ozone aging resistance, heat resistance and chemical resistance.

Hydrogenated nitrile-butadiene rubber, like nitrile-butadiene rubber, increases the content of acrylonitrile (ACN), improves the resistance to petroleum-based oil and fuel oil, but decreases its low-temperature performance. The content of acrylonitrile is usually between 18% and 50%. Hydrogenated nitrile-butadiene rubber (HNBR) fills in the shortcomings of NBR and fluorine rubber in many fields.

Hydrogenated nitrile-butadiene rubber has replaced nitrile-butadiene rubber (NBR) in large quantities and has been used in extremely high temperature environment. Although fluororubber has been proved to have excellent crude oil resistance and processing oil resistance, the test results also show that when placed in modern oil wells with a small amount of amine corrosion inhibitors, it will rapidly aging, so it has also been replaced by hydrogenated nitrile-butadiene rubber.

Advantages of Hydrogenated Nitrile Butadiene Rubber

Excellent heat and oil resistance

Five times more fuel and ozone resistance than NBR

Good wear resistance

Defects of Hydrogenated Nitrile Butadiene Rubber

Like NBR, hydrogenated NBR is not resistant to polar solvents. Hydrogenated nitrile-butadiene rubber (HNBR) is a new elastomer formed by catalytic hydrogenation of NBR. The hydrogenation reaction increases the cold flow property (material deformation caused by the increase of temperature or load applied to the material). The elasticity of HNBR decreases at low temperature due to the change of molecular structure after hydrogenation.

VI. Fluorosilicone Rubber

Like silica gel, fluorosilicone rubber combines trifluoropropyl, methyl and ethylene as side chains, while fluorosilicone rubber is treated by fluorination. The mechanical and physical properties of fluorosilicone rubber are similar to those of silica gel, but fluorosilicone rubber has better physical properties of fuel oil and mineral oil than silica gel, but it is inferior to silica gel in heat resistance. Fluorosilicone rubber has excellent performances of aviation fuel oil, hydraulic oil and synthetic diester lubrication. It can work for a long time at high temperature of 204 degree C (400 degree F). Although mostly used in aerospace field, fluorosilicone rubber has been more and more widely used in sealing parts because of its excellent fuel resistance and high temperature stability.

Advantages of fluorosilicone rubber:

Superior resistance to extreme high and low temperature

Superior compression permanent deformability

Clean, low odor, tasteless

Defects of fluorosilicone rubber:

Because of its low tear resistance, low wear resistance and high friction coefficient, fluorosilicone rubber is only recommended for static seals.

VII. Perfluororubber

Perfluoroelastomer is superior to silicone rubber in high temperature. It has good chemical resistance, resistance to most oils and solvents, weatherability and ozone resistance. The cold resistance of perfluoroelastomer is relatively insignificant.

The advantages of perfluorinated rubber are as follows:

Resistant to heat up to 200 C; Resistant to most oils and solvents, especially all acids, aliphatic hydrocarbons, aromatic hydrocarbons and animal and vegetable oils. The compressive deformation resistance is also good.

Disadvantages of perfluorinated rubber:

The price of raw material sealing ring is higher and the production process is more difficult.

Scope of application of perfluororubber:

Perfluororubber seals are widely used in high temperature, ozone resistance and weatherproof sealing equipment and various high vacuum sealing processes.

With the development of industry, military products are widely used in automobiles, electronics, aerospace, ships and other work environments with high precision, high temperature resistance, high wear resistance and harsh conditions.