Silicone Fluid generally refers to a linear polysiloxane product that remains liquid at room temperature. Generally divided into two types of silicone oil and silicone oil. The most commonly used silicone oil, methyl silicone oil, also known as ordinary silicone oil, all of its organic groups methyl, methyl silicone oil has good chemical stability, insulation, hydrophobic properties. It is obtained by hydrolysis of dimethyldichlorosilane initial polycondensation ring, the ring after cracking, distillation obtained low-loop body, and then the ring, the head of the catalyst together with the telomerization can be obtained A mixture of different degrees of polymerization, the vacuum distillation to remove low boilers can be obtained silicone oil.
Silicone Fluid is generally colorless (or light yellow), tasteless, non-toxic, non-volatile liquid. Silicone oil insoluble in water, methanol, diol and - ethoxyethanol, with benzene, dimethyl ether, methyl ethyl ketone, carbon tetrachloride or kerosene miscible, slightly soluble in acetone, dioxane, ethanol and butanol . It has a small vapor pressure, high flash point and ignition point, lower freezing point. With the different number of segments n, the molecular weight increases, the viscosity also increases, solid silicone oil can have a variety of different viscosities, from 0.65 centistokes up to millions of centistokes. If you want to make low viscosity silicone oil, acid clay can be used as a catalyst, and at 180 ℃ temperature telomerization, or with sulfuric acid as a catalyst, at low temperature telomerization, the production of high viscosity silicone oil or viscous material can be alkaline catalyst.
Silicone oil has excellent heat resistance, electrical insulation, weather resistance, hydrophobicity, physiological inertia and small surface tension, in addition to low viscosity coefficient, high compression resistance, and some varieties also have resistance to radiation Performance.
Silicone oil has many special properties, such as small temperature coefficient of adhesion, high and low temperature resistance, oxidation resistance, high flash point, low volatility, good insulation, small surface tension, non-corrosive to metal, non-toxic and so on. Due to these characteristics, silicone oil has excellent effects for many applications. In a variety of silicone oils, methyl silicone oil is the most widely used, is the most important silicone oil varieties, followed by methyl phenyl silicone oil. Various functional silicone oil and modified silicone oil is mainly used for special purposes.
Traits: colorless, tasteless, non-toxic and non-volatile liquid.
Uses: There are a variety of different viscosity. Has high heat resistance, water resistance, electrical insulation and small surface tension. Commonly used as advanced lubricants, anti-vibration oil, insulating oil, defoamers, mold release agents, polishing agents, release agents and vacuum diffusion pump oil; emulsion can be used for car tire polishing, dashboard and so on. Methyl silicone oil is most commonly used. Emulsified or modified by the smooth finishing of the textile finishing soft touch finishing, daily care products shampoo also added emulsion silicone oil to improve hair lubricity. In addition, ethyl silicone oil, methylphenyl silicone oil, nitrile-containing silicone oil, polyether-modified silicone oil (water-soluble silicone oil) and so on.
(1) The viscosity-temperature performance is the best among the liquid lubricants, and the viscosity changes little in the wide temperature range. Its freezing point is generally less than -50 ℃, and some up to -70 ℃, long-term storage at low temperatures, the appearance of the oil, no change in viscosity, it is high temperature, low temperature, wide temperature range of both base oil.
(2) Excellent thermal oxidation stability, such as thermal decomposition temperature> 300 ℃, low evaporation loss (150 ℃, 30 days, evaporation loss of only 2%), oxidation test (200 ℃, 72h), viscosity and acid value small.
(3) excellent electrical insulation, volume resistance, etc. at room temperature ~ 130 ℃ range does not change (but the oil can not contain water).
(4) It is a non-toxic and low foaming, strong anti-foam oil, can be used as defoamers.
(5) excellent shear stability, vibration absorption, to prevent the spread of vibration function, can be used as damping fluid.
(1) The lubricity of silicone oil is not good, especially the lubricity of steel friction pair is poor.
(2) larger thermal expansion coefficient of silicone oil (overpressure problems may occur).
(3) large gas solubility (difficult to design gas seal device).
(4) a certain degree of hygroscopicity (water content higher than 100 × 10-6 later, a drastic decline in electrical properties).
(5) small surface tension (easy to leak from the machine).