FLOURORUBBER rubber seal

RUBBER FLOURO RUBBER

Fluorelastomer refers to a synthetic polymeric elastomer that contains fluorine atoms on the carbon atom of the main chain or the side chain. Since the CF bond energy is large (485kJ per mol) and the covalent radius of the fluorine atom is 0.064 nm, equivalent to half the CC bond length, the fluorine atom can well protect the CC main chain and ensure ensure the stability of the CC chain, So it has excellent properties that other rubbers cannot match, such as high temperature resistance, oil resistance, chemical resistance, mechanical properties, etc. Good handling, weather resistance, electrical insulation and radiation resistance, etc. and its comprehensive performance better in all synthetic rubber. Good, often referred to as “”.

Types

Fluorine rubber 23, commonly known as No. 1 rubber in China, is a copolymer of vinylidene fluoride and chlorotrifluoroethylene.

Fluorine rubber 26, commonly known as No. 2 rubber in China, is a copolymer of vinylidene fluoride and hexafluoropropylene, and its overall performance is better than No. 1 rubber.

246 fluorine rubber, commonly known as number 3 rubber in China, is a terpolymer of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene. The fluorine content is higher than rubber 26, and it has good solvent resistance.

TP fluorinated rubber, commonly known as domestic tetrapropylene rubber, is a copolymer of tetrafluoroethylene and hydrocarbon propylene, with very good resistance to water vapor and alkali resistance.

Vinylidene fluoride rubber, is a quaternary copolymer of vinylidene fluoride, tetrafluoroethylene, perfluoromethyl vinyl ether, and vulcanization point monomer, with excellent low temperature performance.

Perfluoroether rubber, has high temperature resistance, high fluorine content and excellent solvent resistance. Fluorosilicone rubber has excellent low temperature performance and certain solvent resistance.

Fluorine rubber is mainly used in the automotive and motor vehicle industries. Due to its excellent high temperature resistance, oil resistance and medium resistance, it is mainly used for oil seals and O-rings.

Main performance

good stability

Fluorine rubber has high chemical stability, and it is one of all elastomers with better resistance to the environment. Type 26 fluororubber is resistant to petroleum-based oils, diester oils, silicone ether oils and silicic acid oils. It is resistant to inorganic acids, most organic and inorganic solvents, chemicals, etc., but not to low molecular ketones, ethers, etc. Ester, not resistant to amines, ammonia, hydrofluoric acid, chlorosulfonic acid, phosphoric acid hydraulic oil. The average performance of type 23 fluorine rubber is similar to that of type 26, and it is more unique. It is resistant to strong oxidizing inorganic acids such as fuming nitric acid and denser sulfuric acid than grade 26. It is impregnated in 98% HNO3 at room temperature. 27 Its volume expansion is only 13%~15%.

High temperature resistance

The high temperature resistance of the fluoroelastomer is the same as that of silicone rubber, and it can be said to be the better one among the elastomers available today. 26-41 fluorine rubber can be used for a long time at 250°C and for a short time at 300°C; 246 fluorine rubber has better heat resistance than 26-41. The physical properties of grade 26-41 after air aging at 300 ℃ × 100 h are comparable to grade 246 after air aging at 300 ℃ × 100 h. The elongation at break can be maintained at about 100% and the hardness at 90 to 95 degrees. . Type 246 maintains good elasticity after aging in hot air at 350°C for 16 hours, and maintains good elasticity after aging in hot air at 400°C for 110 minutes. After heating in hot air at 400°C for 110 minutes, it contains spray black carbon, thermal black or carbon fiber. The elongation of the rubber compound increases by about 1/2 to 1/3, and the strength decreases by about 1/2, while retaining good elasticity. Type 23-11 fluorine rubber can be used for long periods at 200°C and for short periods at 250°C.

Against aging

Fluorine rubber has good weather resistance and ozone resistance. It is reported that after ten years of natural storage and no obvious cracking after 45 days of exposure in the air with an ozone concentration of 0.01%. Type 23 fluororubber has better weather resistance and ozone resistance.

Vacuum performance

26 type fluorine rubber has good vacuum suction performance. The vacuum escape rate of vulcanized rubber with the basic formula of 246 fluorine rubber is only 37 × 10-6 Torr/sec. Cm 2. 246 fluoroelastomer has been successfully applied under vacuum 10-9 Torr.

Mechanical behavior

Fluorine rubber has excellent mechanical properties. Type 26 fluororubber typically has a composite strength of 10-20 MPa, a break elongation of 150-350% and a tear strength of 3-4KN/m. Grade 23 fiber strength is from 15.0 to 25MPa, elongation from 200% to 600%, and tear resistance from 2 to 7MPa. In general, the compressive strain of fluorine rubber at high temperature is large, but if compared under the same conditions, such as compression strain at 150 at the same time, both butyl and chloroprene rubber are large. than fluorine rubber type 26, type 26 The compression set of fluorine rubber at 200 °C × 24 hours is equivalent to the compression set of butadiene rubber at 150 °C × 24 hours.

electrical performance

Type 23 fluororubber has better electrical properties and lower hygroscopicity than other elastomers, so it can be used as a better electrical insulator. Type 26 rubber can be used under low frequency and low pressure.

low breathability

Fluorine rubber has relatively large gas solubility, but the diffusion rate is relatively small, so the overall air permeability is also small. According to reports, the permeability of type 26 fluororubber to oxygen, nitrogen, helium and carbon dioxide gases at 30 °C is comparable to butyl rubber and butadiene rubber, and better than neoprene and natural rubber.

low temperature performance

The low temperature performance of fluorine rubber is not good, which is due to its own chemical structure, such as type 23-11 Tg > 0 ℃. The actual low temperature performance of fluorine rubber is usually expressed by the brittle temperature and the compressive cold resistance coefficient. The formulation of the rubber compound and the shape of the product (such as thickness) have a relatively large influence on the embrittlement temperature. If the amount of filler in the recipe is increased, the brittleness temperature will be sensitively reduced, and the product thickness will increase, and the degree of brittleness will also be sensitively reduced.

Anti-radiation

The radiation resistance of fluororubber is one of the inferior elastomers. Type 26 rubber exhibits a post-radiation cross-linking effect, while type 23 fluororubber exhibits a cracking effect. The performance of the Type 246 fluororubber changed significantly under a dosage of 5 × 107 luns under normal temperature radiation in air. In the 1 × 107 lump condition, the hardness increases by 1 to 3 degrees, the strength decreases by less than 20%, and the elongation decreases by 30%-50%. Therefore, it is generally believed that type 246 fluorine rubber can withstand 1 × 107 holes, that is, 5 × 107 holes.