How Impregnants Improve The Performance Of Graphite Hydraulic Oil Seal Materials
Jan 18, 2022
We all know that if the graphite sealing material is directly sintered, there will be leakage, and the overall strength will be compromised. This is due to the fact that during the roasting process of the graphite sealing material, the volatile substances in the binder are volatilized, the binder is polymerized, dispersed and carbonized, and 10-30% pores appear. The improvement measures are to impregnate it to obtain impermeable graphite hydraulic oil products, and to improve the strength of the overall seal. Graphite hydraulic oil seal materials can be impregnated in a variety of different materials to control the performance of their seals.
When the graphite hydraulic oil seal material is impregnated, the properties of the impregnating agent determine the chemical properties, thermal stability, mechanical hydraulic strength and usable temperature range of the impregnated graphite hydraulic oil seal material.
At present, according to the industry, the common impregnating agents are synthetic resin and metal impregnating agents for two types of graphite hydraulic oil seal materials. Some common impregnating resins are phenolic resins (phenolic resins are also called bakelite, also known as bakelite powder. Originally colorless or yellow-brown transparent materials, market sales often add colorants and appear red, yellow, black, green, brown, Blue and other colors, in particle, powder and other shapes. Resistant to weak acid and weak base, and will corrode in case of strong base. Insoluble in water, alcohol and other solvents. Obtained by polycondensation of phenolic or its derivatives. Epoxy resin (epoxy resin is Refers to the compounds containing two or more epoxy groups in the molecule, except for a few, their relative molecular mass is not high,) and furan resin (furfuryl alcohol resin is a kind of furan resin series products. Furan Resin refers to the general term for resins produced by furfuryl alcohol and furfural as raw materials, which are solidified into insoluble and infusible solids under the action of strong acid. resin, etc.).
Three resins for rubber hydraulic oil seals
Among them, phenolic resin is resistant to acid, epoxy resin is resistant to alkali, and furan resin (furfuryl alcohol resin) is resistant to acid and alkali. Among these three resins, the resin impregnated with graphite is furan resin. When the temperature of the hydraulic seal ring is less than or equal to 170 degrees Celsius, we can impregnate carbon graphite with synthetic resin; and when the temperature is greater than 170 degrees Celsius, we should choose a graphite hydraulic oil seal ring impregnated with metal, and we must also consider the melting point of metal impregnated, medium corrosion resistance, etc. When the hydraulic oil seal ring handles high temperature media, antimony-impregnated graphite can be used.
