Industrial additives: basic characteristics and uses of methyl silicone oil

What is methyl silicone oil: Methyl silicone oil is generally a colorless, odorless, non-toxic, non-volatile liquid, insoluble in water, methanol, and ethylene glycol. It is miscible with benzene, dimethyl ether, carbon tetrachloride or kerosene, and slightly soluble in acetone, dioxane, ethanol and butanol. Methyl silicone oil is a linear polyorganosiloxane with Si-O-Si as the main chain and two methyl and trimethylsiloxy groups connected to the Si end-capped. It is liquid at room temperature and its structural formula is as follows:

Product Features

Good heat resistance

Since the main chain of silicone oil molecules is composed of -Si-O-Si- bonds, it has a structure similar to that of inorganic polymers, and its bond energy is very high, so Has excellent heat resistance.

Good oxidation resistance and weather resistance

Good electrical insulation

Silicon oil has good dielectric properties, and its electrical properties change very little with changes in temperature and cycle number. The dielectric constant decreases with increasing temperature, but the change is small. The power factor of silicone oil is low, increases with temperature, but changes with frequency without rules. Volume resistivity decreases as temperature increases.

Good hydrophobicity

Although the main chain of silicone oil is composed of polar Si-O bonds, the non-polar alkyl groups on the side chains are oriented outward, preventing water molecules from Entering the interior, it acts as a hydrophobic agent. The interfacial tension of silicone oil to water is about 42 dynes/cm. When diffused on glass, due to the water repellency of silicone oil, a contact angle of about 103° is formed, which is comparable to paraffin wax.

Small viscosity-temperature coefficient

The viscosity of silicone oil is low and changes little with temperature, which is related to the spiral structure of silicone oil molecules. Silicone oil is a type of oil with the best viscosity and temperature characteristics among various liquid lubricants. This characteristic of silicone oil is very meaningful for damping equipment.

High compression resistance

Due to the spiral structure characteristics of silicone oil molecules and the large distance between molecules, it has high compression resistance. This characteristic of silicone oil can be used as a liquid spring. Compared with mechanical springs, the volume can be greatly reduced.

Low surface tension

Low surface tension is a characteristic of silicone oil. Low surface tension indicates high surface activity. Therefore, silicone oil has excellent defoaming and anti-foaming properties, isolation properties from other substances, and lubrication properties.

Non-toxic, odorless and physiologically inert

From a physiological point of view, silicone polymers are among the most inactive compounds known. Dimethicone is biologically inert and has no rejection reaction with animal bodies. Therefore, they have been widely used in the surgical and internal medicine, pharmaceutical, food and cosmetic sectors.

Good lubricity

Silicone oil has many excellent properties as a lubricant, such as high flash point, low freezing point, thermal stability, small viscosity change with temperature, non-corrosive to metals and good for rubber, Plastics, coatings, and organic paint films have no adverse effects, have low surface tension, and are easy to spread on metal surfaces. In order to improve the lubricity of silicone oil on steel, lubricity additives that are miscible in silicone oil can be added. The lubrication properties of silicone oil can be greatly improved by introducing a chlorophenyl group into the siloxane chain or replacing the dimethyl group with trifluoropropylmethyl.

Application of methyl silicone oil in mechanical and electrical industry

Dimethicone is a transparent, colorless, tasteless, odorless and non-toxic oily liquid. It has the characteristics of high flash point, low freezing point, good thermal stability, and high and low temperature resistance. It is widely used as insulation, lubrication, shockproof, dustproof oil, dielectric fluid and heat carrier.