Characteristics and application of dimethyl silicone oil

The linear dimethyl silicone oil with Si-O-Si as the main chain and a methyl group attached to the silicon atom has a spiral structure due to the small inter-molecular force, and the methyl group is arranged outward and free to rotate.

Therefore, it has a series of characteristics, such as colorless and transparent, wide viscosity range (from 0.65 to 1000000mm2/s), small temperature viscosity coefficient, large expansion coefficient, low vapor pressure, high flash point, high and low temperature resistance, weather resistance and radiation resistance. Low surface tension, high compressibility, oxidation resistant plasma, high insulation, shear resistance, film forming, hydrophobic, defoaming, demoulding, high gloss, inert to materials, chemically inert, non-corrosive and physiologically inert It is these characteristics that determine its broad use.

Generally speaking, according to the viscosity range of dimethyl silicone oil, it can be divided into three types of specifications: low viscosity silicone oil 0.65~50mm2/s; medium viscosity silicone oil 50~1000mm2/s; high viscosity silicone oil 5000~1000000mm2/s.

A certain viscosity of dimethyl silicone oil can be obtained by adjusting the amount of chain stopper during synthesis, but it can also be obtained by mixing two different viscosity dimethyl silicone oils. The calculation formula is as follows:

In principle, any two viscosity dimethyl silicone oils can be mixed, but the viscosity difference is too large, which will affect the shear resistance.

Application of dimethicone

1. Application in the electromechanical industry

      It is widely used in motors, electrical appliances, and electronic instruments as an insulating medium for temperature resistance, arc corrosion resistance, corrosion resistance, moisture resistance, and dust resistance. It is also used as an impregnating agent for transformers for transformers, capacitors, and televisions. Used as a liquid shockproof and damping material in various precision machinery, instruments and instruments. The vibration-absorbing performance of 201 methyl silicone oil is less affected by temperature, and it is often used in the case of instruments with strong mechanical vibration and large changes in ambient temperature, such as aircraft and automobile instruments.

2, for sewing thread smoothing agent

      Methyl silicone oil is widely used as a fiber raw material, an oil agent for raw cotton, an oil agent for spinning, and a smoothing agent for sewing threads. The oil for raw silk and raw cotton is a low viscosity methyl silicone oil. The smoothing agent for sewing thread is medium to high viscosity methyl silicone oil. The use of methyl silicone oil thermal stability and low viscosity temperature coefficient, with antistatic agent, emulsifier and other oil agent made of spinning oil agent, used in nylon, poly cool spinning process, to prevent spinning The extremely thin monofilament bundle is broken and loose due to electrification at the time of ejection from the nozzle and rapid winding. When melting and anti-filament, the nozzle should also be treated with methyl silicone oil as a mold release to prevent the carbide or molten material from adhering to cause broken yarn.

3, as a defoamer

      Because dimethyl silicone oil has small surface tension and is insoluble in water, animal and vegetable oils and high-boiling mineral oils, it has good chemical stability and is non-toxic. It has been widely used in petroleum, chemical, medical, pharmaceutical and food industries as defoamers. In the processing, textile, printing and dyeing, papermaking and other industries, as long as the addition of 10-100PPM of silicone oil has a good defoaming agent.

4, as a release agent

      It is non-tacky with rubber, plastic, metal, etc. It is also used as a release agent for various rubber and plastic products, and used in precision casting. It is not only easy to demould, but also makes the surface of the product clean, smooth and clear.

5, for insulation, dust, mildew coating

      A layer of 201 methyl silicone oil is immersed on the surface of the glass and ceramics, and after heat treatment at 250-300 ° C, a semi-permanent waterproof, mildewproof and insulating film can be formed. The insulating device can be used to improve the insulation performance of the device: the optical instrument can be used to prevent the lens and the prism from being moldy; the treatment of the medicine bottle can prolong the storage period of the medicine, and does not cause the preparation to be lost due to sticking; The surface of the film can be used to lubricate, reduce friction and extend the life of the film.

6, as a lubricant

      Used as a lubricant for rubber, plastic bearings and gears. It can also be used as a rolling friction of steel against steel at high temperatures or as a lubricant when rubbing steel with other metals.

7, as an additive

      It can be used as an additive for many materials. For example, it can be used as a brightening agent for paints. Add a small amount of silicone oil to the paint to make the paint not float, wrinkle and improve the brightness of the paint film. Add a small amount of silicone oil to the ink to improve printing. Quality, add a small amount of silicone oil to the polishing oil (such as automotive varnish), can increase the brightness, protect the paint film, and have excellent waterproof effect.

8. Application in medical and health

      It is not toxic to the human body and is not decomposed by human body fluids, so it is widely used in medical and health care. Using its antifoaming effect, it has been made into oral gastrointestinal augmentation tablets, and pulmonary edema defoaming aerosols and the like. Adding silicone oil to the ointment can improve the penetration of the drug into the skin and improve the efficacy. Some pastes based on silicone oil have good curative effect on scald, dermatitis and hemorrhoids. The anticoagulant effect of silicone oil can be used to treat the surface of the blood reservoir and prolong the storage time of the blood sample.

9, others

      It is used as a heat carrier in oil baths or thermostats in industries such as steel, glass, ceramics, etc., with its high flash point, odorless, colorless, transparent and non-toxic to the human body. With its good shear resistance, it can be used as hydraulic oil, especially aviation hydraulic oil. By treating the rayon spinning head with it, the static electricity can be eliminated and the spinning quality can be improved. Adding silicone oil to cosmetics can improve the moisturizing and protective effects on the skin.