Fluorosilicone rubber is an elastomer material that combines the characteristics of both silicone rubber and fluororubber. Compared with methyl vinyl silicone rubber, its biggest advantage is oil and solvent resistance. Compared with fluororubber, although there is little difference in resistance to alkane solvents, its resistance to aromatic solvents is better than that of fluororubber. Its good solvents are only ketones with high polarity and small molecules. Fluorosilicone rubber has better heat resistance, cold resistance, and compression set, and its physical properties have less dependence on temperature. It shows excellent performance from low temperature to high temperature. Secondly, products with low hardness can be made without using plasticizers. Therefore, fluorosilicone rubber, as a new high-performance elastomer material, is being widely used.
The applications of fluorosilicone rubber are mainly in the fields of aerospace, vehicles and ships, electronic communications, precision instruments, petrochemicals, and healthcare. But currently, the industries with the largest market demand are rocket, satellite, automobile, and aircraft manufacturing.
Aerospace films: Diaphragms for valves in fuel tank pressure regulating pipelines, diaphragms for fuel tank ventilation valves (laminated films with fluorosilicone rubber coatings and polyester fabrics as skeleton materials used in kerosene vapor at -55°C to 200°C and 150°C RP kerosene); Static and dynamic seals: washers, cups, valves. Automotive products: fuel level indicator sensor hoses, atomizer oil pump diaphragms, fuel pump diaphragms, corrugated sheaths, engine crankshaft rear sealing rings, cylinder gaskets, fuel pump seals, fuel tank cap gaskets, fuel tank filler gaskets, filter element seals;
Others: Seals resistant to fluorochlorinated oil, fluorobrominated oil, trichlorobenzene, H2S solution, liquid nitrogen, etc.
Fluorosilicone rubber has outstanding high temperature resistance, oil resistance, especially resistance to diester oils, chemical resistance, good physical and mechanical properties, satisfactory dielectric properties, non-flammability, weather resistance, excellent vacuum properties, and radiation resistance. It can usually be used for a long time at 275°C and for a short time at 320°C. Its oil and acid resistance is better than that of No. 1 rubber. Its weather resistance, ozone resistance, radiation resistance, air permeability, electrical properties and flame resistance are similar to those of No. 2 rubber. It is widely used in aerospace, automotive, machinery, petrochemical and other fields. For example, it is used as static and dynamic sealing materials for the hydraulic system and lubrication system of aircraft; it is used as sealing materials for oil fields, cable oil pipelines and drilling equipment in oil fields; in the chemical industry, it is used as lining for equipment, flexible connections of pipelines, pumps, etc. or as corrosion-resistant sealing materials to make pipelines for transporting organic solvents or other corrosive media, etc.
Compared with methyl vinyl silicone rubber, fluorosilicone rubber has extremely excellent oil resistance, solvent resistance, and chemical resistance. Even compared with fluororubber, its oil and solvent resistance is also good. After immersion in the same medium, temperature, and time, it shows excellent durability. It can be said that fluorosilicone rubber is the only elastomer that is resistant to non-polar media at -68°C to 232°C. The resistance of fluorosilicone rubber to methanol-containing gasoline is also relatively good. Even in the gasoline/methanol mixed system, the hardness, tensile strength, and volume change of the vulcanizate are very small. After a 500-hour long immersion test, the physical properties are almost unchanged.
The high-temperature decomposition of fluorosilicone rubber is the same as that of silicone rubber, that is, side chain oxidation, main chain fracture, side chain thermal decomposition, and various complex reactions. Since the decomposition products can also cause main chain fracture, the heat resistance is usually worse than that of silicone rubber. Oxidation and aging begin at a temperature of 200°C. However, by adding a small amount of heat stabilizers such as iron, titanium, and rare earth oxides, it can be significantly improved. Even at a high temperature of 250°C, it has sufficient heat resistance. The influence of temperature on fluorosilicone rubber is greater than that on silicone rubber, but less than that on fluororubber.
The weather resistance aging resistance of fluorosilicone rubber is very excellent. Even after being exposed for 5 years, it still maintains good performance. Ozone is one of the gases most generated during the aging of elastomers. However, no cracks or fissures are found in fluorosilicone rubber after dynamic or static tests. In addition, the mildew resistance, physiological inertness, and anticoagulant properties of fluorosilicone rubber are also very good. Fluorosilicone rubber is resistant to various inorganic, organic, polar, and non-polar oils such as olive oil, safflower oil, makeup remover oil, lubricating oil, brake oil, and hydraulic oil. It does not expand, does not shrink, has stable dimensions, and has a long-lasting oil resistance effect.