Dimethylsilicone oil, also known as polydimethylsiloxane, is a hydrophobic silicone material.

Colorless or yellowish liquid, non-toxic, tasteless, transparent, transparent for 100%, with heat resistance, cold resistance, viscosity with temperature change small, waterproof, surface tension, thermal conductivity, thermal conductivity of 0.134-0.159W/M*K, with physiological inertia, good chemical stability. It has good electrical insulation, weatherability, hydrophobicity, and high shear resistance. It can be used for a long time at - 50 ~200 C.

II. PRODUCTION TECHNOLOGY

Dimethyl silicone oil is usually prepared by ring opening polymerization with dimethyl cyclosiloxane mixture (DMC) as raw material, hexamethyldisiloxane (MM) or low viscosity dimethyl silicone oil as end-capping agent under the action of acidic or alkaline catalysts. Among them, acidic catalysts are suitable for the synthesis of low viscosity silicone oil. The common catalysts are concentrated sulfuric acid, trifluoromethanesulfonic acid, solid acid, alkaline catalysts are suitable for medium and high viscosity silicone oil, common KOH, (CH3) 4NOH, etc.

The production process is divided into batch process and continuous process.
1. Mechanical and Electrical Industry


Dimethyl silicone oil is widely used in electrical machinery, electrical appliances and electronic instruments as insulation medium for temperature resistance, arc corona resistance, corrosion resistance, moisture-proof and dust-proof. At present, it is also used as impregnating agent for scanning transformers of transformers, capacitors and TV sets. In all kinds of precision machinery, instruments and instruments, it is used as liquid shock-proof and damping material. The shock absorption performance of dimethyl silicone oil is less affected by temperature. It is mostly used in the instruments of aircraft and automobiles when there is strong mechanical vibration and the ambient temperature changes greatly. It can be used for shock-proof, damp and stabilizing instrument reading, and also as a liquid spring for aircraft landing device.


2. Defoamer


Dimethyl silicone oil has low surface tension and is insoluble in water, animal and vegetable oils and mineral oils with high boiling point. It is chemically stable and non-toxic. It has been widely used as defoamer in petroleum, chemical, medical, pharmaceutical, food processing, textile, printing and dyeing, paper and other industries.


3. Demoulding agent


Dimethyl silicone oil is not sticky with rubber, plastics, metals, etc. It is also used as release agent for various rubber and plastic products forming and processing, and in precision casting. Using it as demoulding agent not only demoulds conveniently, but also makes the surface of products clean, smooth and texture clear.


4. Insulation, Dust-proof and Mildew-proof Coatings


After dipping a layer of dimethyl silicone oil on the surface of glass and ceramics and heat treatment at 250-300 C, a semi-permanent film of waterproof, mildew-proof and insulation can be formed. Using it to deal with insulating devices can improve the insulation performance of devices: using it to deal with optical instruments can prevent lens and prism from mildewing; using it to deal with bottles can prolong the shelf life of medicines without causing the loss of preparations due to wall adhesion; using it to deal with the surface of film can play a lubricating role, reduce friction and prolong the life of film.


5. Lubricants


Dimethyl silicone oil is suitable for lubricating rubber, plastic bearings and gears. It can also be used as a lubricant for rolling friction of steel at high temperature or friction between steel and other metals. However, because the lubrication performance of methyl silicone oil at room temperature is not very good, it is not recommended as a lubricant between metals at normal temperature.


6. Additives


Dimethyl silicone oil can be used as additives for many materials, such as brightener for paint, adding a small amount of silicone oil to the paint, which can make the paint not floating, wrinkle-free and improve the brightness of the paint film. Adding a small amount of silicone oil to the ink can improve the printing quality. Adding a small amount of silicone oil to the polishing oil (such as automobile polishing oil) can increase the brightness, protect the paint film, and have excellent waterproof effect.