Dimethicone, also known as methyl silicone oil or polydimethylsiloxane liquid, has an average molecular weight range of 5000 to 100000. This unique molecular structure gives it a series of excellent properties, including extremely low surface tension, high compressibility, excellent shear resistance, small viscosity-temperature coefficient and extremely low dielectric loss.

In addition, dimethicone also exhibits good arc and corona resistance, is non-flammable, and has excellent hydrophobicity and physiological inertness. These characteristics make dimethicone an ideal choice for electrical insulation, heat-resistant and moisture-proof fillers, high-efficiency defoamers, release agents, lubricants and surface treatment agents.

Synthesis method

Dimethicone is mainly polymerized by octamethylcyclotetrasiloxane and hexamethyldisiloxane under the action of a specific catalyst (such as concentrated sulfuric acid or tetramethylammonium hydroxide). This chemical reaction process can accurately control the molecular weight distribution of the product, thereby ensuring the performance stability of the final product.

Toxicity assessment and safe use

From a toxicological point of view, dimethicone is extremely safe for humans and mammals. No obvious toxic reaction was found in either acute or chronic exposure, and no mutagenic or carcinogenic effects were found. Its low irritation and low absorption ensure safety during use, and it will not cause significant irritation or allergic reaction to the eyes or skin whether it is taken orally, inhaled or in contact with the skin.

Diversified Applications of Dimethicone

Dimethicone is widely used, mainly as a demoulding agent for various materials such as plastics and rubber, showing excellent high and low temperature resistance, light transmittance, electrical properties, hydrophobicity, moisture resistance and chemical stability. It is particularly suitable for high-temperature demoulding of large molded objects, such as phenolic resins and unsaturated polyester laminates.

In order to meet the needs of different uses, dimethicone is usually processed into solutions, emulsions and silicone pastes. The solution is prepared by dissolving silicone oil in organic solvents such as carbon tetroxide, toluene or xylene. The concentration is generally 0.5% to 2%, and it is suitable for a temperature range of 60 to 110°C. Emulsions are prepared from silicone oil, emulsifiers and water, and are diluted to 0.5% to 2.0% when used. They are suitable for processing occasions above 120°C and products with complex shapes. Silicone pastes are made of silicone oil and ultrafine silica, have good heat resistance, and are suitable for products with large, smooth surface areas and simple shapes.

As a polymer of dimethyl silicon, dimethyl silicone oil (simethicone) has different grades of products according to different polymerization degrees. As a condensing agent for pellets, it can select the appropriate relative density and viscosity according to the properties of the matrix. All water-soluble matrices can be well formed in it, although the cost is high.

Dimethyl silicone oil has also been widely used in the fields of electrical insulation, lubrication, shock and moisture resistance, defoaming, damping, heat carrier and hydraulic oil. In addition, it can also be used as an additive for paints and polishes to improve the demoulding and wear resistance of plastic processing. In the fields of daily chemicals and medicine, dimethyl silicone oil is also an important ingredient for the preparation of cosmetics and certain drugs.

Conclusion

Due to its unique properties and wide application, dimethyl silicone oil has become an indispensable and important material in many industries. With the continuous development of science and technology, the application field of dimethyl silicone oil is still expanding, and it is expected to play a greater role in more fields in the future. Whether in daily life or in industrial production, dimethyl silicone oil has shown its unique value and potential.