What are the main properties of fluorine rubber

Fluorine rubber has a high degree of chemical stability and is one of the medium resistance properties of all elastomers. Type 26 fluororubber is resistant to petroleum-based oils, diester oils, silicone ether oils, silicic acid oils, inorganic acids, most organic and inorganic solvents, pharmaceuticals, etc., and is not resistant to low-molecular ketones, ethers, and esters. , Not resistant to amines, ammonia, hydrofluoric acid, chlorosulfonic acid, phosphoric acid hydraulic oil. The dielectric performance of type 23 fluorine rubber is similar to that of type 26, and it is more unique. Its resistance to strong oxidizing inorganic acids such as fuming nitric acid and concentrated sulfuric acid is better than that of type 26. It can be impregnated in 98% HNO3 at room temperature for 27 Its volume expansion is 13%~15%.

good stability

Viton has a high degree of chemical stability, and it is one of the most medium-resistant properties among all elastomers. Type 26 fluororubber is resistant to petroleum-based oils, diester oils, silicone ether oils, silicic acid oils, inorganic acids, most organic and inorganic solvents, pharmaceuticals, etc., and is not resistant to low-molecular ketones, ethers, and esters. , Not resistant to amines, ammonia, hydrofluoric acid, chlorosulfonic acid, phosphoric acid hydraulic oil. The dielectric performance of type 23 fluorine rubber is similar to that of type 26, and it is more unique. Its resistance to strong oxidizing inorganic acids such as fuming nitric acid and concentrated sulfuric acid is better than that of type 26. It can be impregnated in 98% HNO3 at room temperature for 27 Its volume expansion is 13%~15%.

High temperature resistance

The high temperature resistance of fluorine rubber is the same as that of silicone rubber, which can be said to be the best among elastomers at present. 26-41 fluorine rubber can be used for a long time at 250°C, and short-term use at 300°C; 246 fluorine rubber has better heat resistance than 26-41. The physical properties of 26-41 after 300°C×100 hours of air heat aging are equivalent to those of 246 after 300°C×100 hours of hot air aging, its elongation at break can be maintained at about 100%, and its hardness is 90~95 degrees . Type 246 maintains good elasticity after 16 hours of hot air aging at 350°C, good elasticity after 110 minutes of hot air aging at 400°C, and contains spray carbon black, thermal black or carbon fiber after 110 minutes of hot air aging at 400°C The elongation of the rubber compound increased by about 1/2~1/3, the strength decreased by about 1/2, and still maintained good elasticity. 23-11 type fluorine rubber can be used at 200°C for a long time, and at 250°C for a short time.

Aging resistance

Viton has excellent weather resistance and ozone resistance. According to reports, the performance of VitonA developed by DuPont is still satisfactory after ten years of natural storage, and there is no obvious cracking after 45 days in the air with an ozone concentration of 0.01%. Type 23 fluororubber has excellent weather resistance and ozone resistance.

Vacuum performance

26 fluororubber has excellent vacuum performance. The vacuum outgassing rate of the vulcanized rubber in the basic formula of 246 fluororubber is 37×10-6 Torr liters/sec.cm2. The 246 type fluororubber has been successfully applied under the vacuum condition of 10-9 Torr.

Mechanical behavior

Viton has excellent physical and mechanical properties. The strength of 26 type fluorine rubber is generally between 10~20MPa, the elongation at break is between 150~350%, and the tear strength is between 3~4KN/m. The strength of type 23 fluororubber is between 15.0~25MPa, the elongation is between 200%~600%, and the tear strength is between 2~7MPa. Generally, the compression deformation of fluorine rubber at high temperature is large, but if compared under the same conditions, for example, from the compression deformation of the same time at 150 ° C, both butyl and chloroprene rubber are larger than 26 type fluorine rubber, and 26 type The compression deformation of fluorine rubber at 200 ° C × 24 hours is equivalent to the compression deformation of butyl rubber at 150 ° C × 24 hours.

Electrical properties

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

Low air permeability

Viton has a relatively high solubility to gas, but its diffusion rate is relatively small, so the overall air permeability is also small. According to reports, 26-type fluorine rubber is comparable to butyl rubber and butyl rubber in terms of oxygen, nitrogen, helium, and carbon dioxide gas permeability at 30 ° C, and is 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 Tg>0℃ of 23-11 type.

The low temperature performance of fluororubber actually used is usually expressed by brittle temperature and compression cold resistance coefficient. The formula of the rubber compound and the shape of the product (such as thickness) have a great influence on the brittleness temperature. If the amount of filler in the formula increases, the brittleness temperature will deteriorate sensitively, and the thickness of the product will increase, and the brittleness will also deteriorate sensitively.

Radiation resistance

The radiation resistance of fluorine rubber is relatively poor among elastomers. Type 26 rubber exhibits cross-linking effect after irradiation, while type 23 fluorine rubber exhibits cracking effect. The performance of 246 type fluororubber changes drastically under the normal temperature radiation in the air at the dose of 5×107 gal. Under the condition of 1×107 gal, the hardness increases by 1~3 degrees, the strength drops by less than 20%, and the elongation drops by 30%~50%. , so it is generally believed that 246-type fluorine rubber can withstand 1×107 gallon, and the limit is 5×107 gallon.