Due to different environmental and environmental requirements, rubber seals use different rubber materials. Rubber seal materials include nitrile rubber, hydrogenated nitrile rubber, acrylic rubber, fluororubber, fluorosilicone rubber, perfluororubber, and other sealing materials.

1、 Nitrile rubber

The most commonly used material in the production of seals is nitrile rubber, which is mainly used in oil resistant sealing products.

Nitrile rubber has excellent resistance to fuel oil and aromatic solvents, and can meet common requirements with low cost.

2、 Natural rubber

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

3、 Acrylic rubber

The comprehensive performance of heat and oil resistance of acrylic rubber is excellent, with a usage temperature of up to 180 ℃ -200 ℃, and it is widely used in products that require high temperature and oil resistance.

Acrylic rubber, also known as automotive rubber, is a suitable material for manufacturing rubber seals, O-rings, gaskets, and hoses used at high temperatures. It is an important material in the automotive industry.

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

The application fields of acrylic rubber are quite extensive - sponge products, deep well exploration, partial replacement of silicone rubber in the electrical industry, and adhesives.

4、 Fluororubber

1. Fluororubber refers to a synthetic polymer elastomer with fluorine atoms on the carbon atoms of the main or side chains.

Advantages of Fluororubber

Among rubber sealing materials, fluororubber has the best heat resistance (decomposition temperature greater than 400 degrees Celsius), oil resistance (various fuels, hydraulic oils, lubricating oils, synthetic oils), solvent resistance, weather resistance (external lines, ozone resistance, radiation resistance), and chemical medium resistance. Fluororubber can be used as a sealing material in high-temperature environments or special working fluids where nitrile rubber and polyurethane rubber cannot be used. It does not self ignite, does not support combustion, and has self extinguishing properties when exposed to fire. It has good physical and mechanical properties and is the most comprehensive among all synthetic rubbers. It is commonly known as the "rubber king" and has become one of the indispensable and alternative basic materials in modern industry, especially in high-tech fields.

Disadvantages of Fluororubber

Its processing technology performance is not easy to master, and the price is relatively high. It is 20 times more durable than nitrile rubber, with poor cold and water resistance, and poor elasticity at room temperature. Fluorine rubber products with improved cold and water resistance have been developed on the market. In addition, FFKM has better resistance and drug resistance than ordinary fluorine rubber, but its price is as much as 10 times higher than fluorine rubber.

Application of Fluororubber Seals

Fluororubber is widely used in national defense, military industry, automobile and aviation, aerospace and petroleum fields. Fluororubber oil seals are also used in drilling machinery, refining equipment, natural gas desulfurization devices, and can withstand harsh environmental conditions such as high temperature, high pressure oil and strong corrosive media. In the chemical field, fluororubber oil seals are used in pumps, pipe joints, equipment containers, for sealing inorganic acids, and other chemical substances; In the military industry, fluororubber is mainly used for oil seals, oil pipes, and electrical circuit sheaths in aerospace, aviation, and carrier rockets, satellites, fighter jets, and new tanks. It is one of the key sealing materials that cannot be replaced in cutting-edge defense industries.

5、 Hydrogenated nitrile rubber

Hydrogenated nitrile rubber is a synthetic polymer that undergoes hydrogenation reaction to saturate the carbon hydrogen chains of nitrile rubber. This special hydrogenation process reduces many double bonds on the main chain of nitrile rubber (NBR) polymer. Therefore, hydrogenated nitrile rubber not only retains the characteristics of original nitrile rubber, but also has higher heat resistance, ozone aging resistance, heat resistance, chemical resistance and mechanical properties than nitrile rubber.

Hydrogenated nitrile rubber, like nitrile rubber, has an increased content of acrylonitrile (ACN), which enhances its resistance to petroleum based oils and fuels, but reduces its low-temperature performance. The content of acrylonitrile is usually between 18% and 50%. Hydrogenated nitrile rubber fills the gaps in the application of nitrile rubber and fluororubber in many fields.

Hydrogenated nitrile rubber has largely replaced nitrile rubber and is used in extremely high temperature environments; Although fluororubber has been proven to have excellent resistance to crude oil and processing oil, test results have also shown that it rapidly ages when placed in modern oil wells containing small amounts of amine corrosion inhibitors, and has therefore been replaced by hydrogenated nitrile rubber.

Advantages of hydrogenated nitrile rubber

Excellent heat and oil resistance

Five times more flame resistant and ozone resistant than nitrile rubber

Good wear resistance

Disadvantages of hydrogenated nitrile rubber

Like nitrile rubber, hydrogenated nitrile rubber is not resistant to polar solvents. Hydrogenated nitrile rubber is a new type of elastomer formed by catalytic hydrogenation of nitrile rubber. The hydrogenation reaction increases its cold flowability (material deformation caused by an increase in temperature or load applied to the material). Due to changes in molecular structure after hydrogenation reaction, the elasticity of HNBR at low temperatures decreases.

6、 Fluorosilicone rubber

Fluorosilicone rubber, like silicone gel, combines trifluoromethyl, methyl, and ethylene as side chains, except that fluorosilicone rubber is treated with fluorination. The mechanical and physical properties of fluorosilicone rubber are similar to those of silicone, but fluorosilicone rubber has better physical properties in terms of fuel and mineral oil resistance than silicone, but is not as heat-resistant as silicone. Fluorosilicone rubber has excellent resistance to aviation fuel oil, hydraulic oil, synthetic diester lubrication, and can work for a long time at high temperatures of 204 ° C (400 ° F). Although mostly used in the aerospace industry, fluorosilicone rubber has become increasingly common in the production of seals due to its superior fuel resistance and stability at high temperatures.

Advantages of fluorosilicone rubber:

Superior resistance to extremely high and low temperatures

Superior compression permanent deformability

Clean, low odor, odorless

Disadvantages of fluorosilicone rubber:

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

7、 Perfluororubber

Perfluororubber has better high-temperature resistance than silicone rubber, with excellent chemical resistance, resistance to most oils and solvents, weather resistance, and ozone resistance; The characteristic of cold resistance is relatively insignificant.

Advantages of Perfluororubber:

Can withstand heat up to 200 ℃; It has the ability to resist most oils and solvents, especially all acids, aliphatic hydrocarbons, aromatic hydrocarbons, and animal and vegetable oils. It also has good resistance to compression deformation;

Disadvantages of perfluororubber:

The price of raw material sealing rings is relatively high, and the production process is difficult;

Scope of application of perfluororubber:

Perfluororubber sealing ring products are widely used in sealing equipment with high temperature, ozone resistance, and weather resistance requirements, as well as various high vacuum sealing processes.

With the development of industry, military products are widely used in working environments such as automobiles, electronics, aerospace, and ships that require high precision, high temperature resistance, high wear resistance, and harsh conditions.