Resistance to hot water and superheated steam
The stability of rubber compound to hot water is not only determined by the main material, but also by the ratio of rubber materials. For rubber compound, peroxide-cured rubber compound is worse than amine and phenol-cured rubber materials. The resistance of rubber compound to hot water and superheated steam is average, not as good as EPDM. After 18024h of superheated water immersion, the volume change is less than 10%, and the physical properties should not change much.
Mechanical properties under normal conditions
The general matching strength of type 26 rubber compound is 10-20Mpa; the growth rate is 150-300%; the tear strength is between 20-40KN/m, but the elasticity is poor. The friction coefficient of fluororubber (0.8) is less than that of nitrile rubber) 0.9~1.5).
High temperature resistance
The high temperature resistance of rubber compound and rubber compound is the best among rubbers at present. F26-41 fluororubber can be used for a long time at 200~250℃, and can also be used for a short time at 300℃ (see Table 1). The heat resistance of F246 is slightly better than that of F26.
Corrosion resistance
The rubber compound has excellent corrosion resistance. It has good stability to organic liquids, different fuel oils, and lubricating oils. It has good corrosion resistance to most inorganic acids, hydrocarbons, benzene, and toluene. It is only weak to low molecular esters, ethers, ketones and some amine compounds.
Compression deformation performance
Rubber compounds are used for sealing at high temperatures, and compression deformation is an important performance. The wide use of lathe-type fluororubber is inseparable from the improvement of its compression deformation. DuPont of the United States has been committed to improving the tolerance of fluororubber to compression deformation since the 1960s and 1970s, and has achieved remarkable results.
Low temperature resistance
The low temperature resistance of rubber compounds is general, and the limit temperature at which elasticity can be maintained is -15~-20℃. As the temperature drops, the tensile strength increases, and it looks very tough at low temperatures. When measuring a standard sample with a thickness of 2mm, the brittle temperature is around -30; when the thickness is 1.87mm, it is -45; when the thickness is 0.63mm, it is -53; when the thickness is 0.25mm, it is -69.
Air permeability
The gas solubility of rubber compound is relatively large, its diffusion rate is relatively small, and the total air permeability is small. In the rubber compound, the gaps inside the rubber are filled by adding fillers, and the air permeability of the vulcanized rubber becomes smaller, which is conducive to vacuum sealing. If properly matched, the rubber compound can solve the vacuum sealing of 10-7Pa.
Flame retardancy
The rubber compound will automatically disappear after leaving the fire if it catches fire.
Electrical properties
The electrical insulation of the rubber compound is not very good, and it is suitable for use under low frequency and low voltage. Temperature has a great influence on its electrical properties. After rising from 24 to 184. the insulation resistance will drop 35.000 times.
Weather resistance and ozone resistance
The performance is still satisfactory after ten years of natural storage. In air with an ozone concentration of 0.01%, there is no obvious cracking after 45 days of action. Its weather resistance and ozone resistance are satisfactory.
