Silicone oil usually refers to the linear polysiloxane that remains liquid at room temperature, and is a class of silicone products with a wide range of applications. According to the different classification of substitution groups on the polysiloxane chain, silicone oil can be divided into: methyl silicone oil, phenyl silicone oil, ethyl silicone oil, hydroxyl silicone oil, amino silicone oil, hydrogen-containing silicone oil, vinyl silicone oil and polyether modified silicone oil, fluorosilicone oil and so on.
Briefly divided by the type of organic group, the corresponding applicability characteristics are shown below.
The following is a description of several types of representative silicone oil varieties.
1、Dimethyl silicone oil
Dimethyl silicone oil is the most common variety of silicone oil, is the largest amount, the most widely used varieties; in China, the trade name of methyl silicone oil for the 201 series, the United States Dow Corning’s brand DOWCORNING and XIAMETER, the main model PMX-200 series; Germany Wacker’s brand AK series; Japan Shin-Etsu’s brand KF series The main models are PMX-200 series; AK series from Wacker, Germany; and KF series from Shin-Etsu, Japan. China’s local methyl silicone oil manufacturers include: Blue Star Jiangxi Starfire, Yichang Kelin Silicon Materials Co.
2、Phenyl silicone oil
Another category of more widely used phenyl silicone oil is the product obtained after partial substitution of methyl by phenyl, according to the different content of phenyl, can be divided into the following categories: low phenyl silicone oil (phenyl molar fraction 5% ~ 10% ); medium phenyl silicone oil (phenyl molar fraction 25%); high phenyl silicone oil (phenyl molar fraction 45%); high phenyl low polymerization silicone oil (phenyl molar fraction higher than 45% ); cross-linked phenyl silicone oil. Cross-linked phenyl silicone oil.
3、Ethyl silicone oil
Various ethyl ethoxysilanes are hydrolyzed and condensed into polysiloxane in the presence of hydrochloric acid, then molecularly rearranged and fractionated under vacuum to obtain various ethyl silicone oils with different viscosities. It is used as a mold release agent for many kinds of rubber and plastic products. It has low volatility, low surface tension, non-toxic, non-corrosive, aging resistance, and can be blended into different viscosities according to the needs of use. It is widely used as insulating material of electrical industry, precision instrument oil, hydraulic oil, special lubricant, etc.
4、Hydroxyl silicone oil
Hydroxyl silicone oil can be used as the structure control agent for room temperature silicone rubber production and chain expansion agent for synthesis of other products, at present, there are mainly Wacker chemical, confidence chemical, Hubei Longma, Blue Star, Zhejiang Hengye Cheng and other enterprises.
5、Amino silicone oil
Amino silicone oil is specifically used for textile soft finishing agent of the basic ingredients, mainly concentrated in Dow Corning, Blue Star, Shandong Dayi Chemical, Demi Wacker, Yichang Colin and other enterprises production. Dow Corning’s grades are mainly OFX series, Metu’s grades are mainly TSF4708, and Shin-Etsu’s grades are DC-8209A.
6、Hydrogen-containing silicone oil
Domestic manufacturers of hydrogen-containing silicone oil use the 202 series name. At present, there are dozens of domestic enterprises producing hydrogen-containing silicone oil, except for Zhejiang Hengye Cheng, Blue Star and Xin’an Chemical, the capacity of other enterprises is below 4,000 tons/year. Dow Corning’s hydrogen-containing silicone oil grades are mostly MHX series, Metu’s grades are TSF series, and Shin-Etsu’s grades are mostly KF-99 series.
7、Vinyl silicone oil
Vinyl silicone oil is the base material for the production of molding liquid rubber and silicone gel, and the main domestic manufacturers are: Bluestar, Zhejiang Xin’an Chemical Group and Zhejiang Runhe. The volume of other companies is relatively small.
8、Modified silicone oil
Among the modified silicone oil, the amount of polyether modified silicone oil is the largest, and it is used as a large number of levelling agent, fiber oiling agent, fabric finishing agent, cosmetic raw material, coating leveling agent, defoaming agent and pesticide spreading agent, etc.; fluorosilicone oil has excellent weather resistance, lubricity and oleophobicity because of the common advantages of both silicone and fluorocarbon, and it should be widely used in the friction field of aerospace, automobile, electromechanical and electronic machinery, etc.
Wide application of silicone oil
At present, silicone oil is mainly used as advanced lubricant, anti-shock oil, insulating oil, defoamer, demoulder, polish, isolating agent and vacuum diffusion pump oil, etc.; emulsion can be used for automobile tire varnish, dashboard varnish, etc. The consumption structure of silicone oil emulsions varies greatly from country to country, and the consumption structures of Europe and the United States are given below.
Distribution of silicone oil consumption in the United States in 2014
Distribution of silicone oil consumption in Western Europe in 2014
Description of silicone oil in each application area
1.Daily chemical industry.
Silicone emulsions can be widely used in cosmetics. Adding the right amount of the product can make cosmetics have the advantages of lubrication, resistance to sunlight as well as ultraviolet radiation, good breathability, etc. Meanwhile, due to the hydrophobic property of silicone oil, it can improve the waterproof and sweat resistance of cosmetics.
2、Textile industry.
Silicone oil in the textile and apparel industry can be used as fabric softener, lubricant, waterproofing agent, finishing agent, etc. In order to meet the high-end needs of textiles, chemical manufacturers are also developing silicone oils that can be used together with various functional additives such as water repellents, flame retardants, antistatic agents, color fixing agents, etc. In addition, there are silicone products that can be used in the same bath with dyeing in order to improve the performance of fabrics, silicone oil for cotton that has a cool feeling, silicone products that can improve the feel of fabrics, and silicone deepening agents that give fabrics excellent deepening effects, good storage stability, do not affect color fastness, and have a good feel, etc.
In addition to the functionalization of textiles as additives, silicone products will also be used in other areas of textiles, such as silicone and polyurethane combination to form the fabric coating; silicone and acrylic polymerization to form the fabric printing; silicone and organic fluorine combination to form the surface of the fabric waterproof coating.
3、Machinery
Damping and shock absorption: Silicone oil is widely used in electric motors, electrical appliances, electronic instruments as temperature resistance, arc corona resistance, corrosion resistance, moisture-proof, dust-proof insulation medium, and is also used as impregnating agent for transformers, capacitors, scanning transformers for televisions, etc. In various precision machinery, instruments and meters, used as liquid anti-vibration, damping materials. Because the silicone oil’s vibration-damping performance is little affected by temperature, it is mostly used in instruments with strong mechanical vibration and large changes in ambient temperature, such as: aircraft, automobile instruments. It is used for anti-shock, damping, stabilizing the meter reading, and also as liquid spring, and in the landing device of the aircraft.
Thermal conductivity: Thermal conductive silicone grease is the most widely used thermal conductive medium, it is an ester-like substance formed by taking silicone oil as raw material and adding thickener and other filler after heating and decompression, grinding and other processes, the substance has a certain viscosity and no obvious granularity. The working temperature of thermally conductive silicone grease is generally from -50℃ to 180℃, and it has good thermal conductivity, high temperature resistance, aging resistance and waterproof characteristics. In the process of device heat dissipation, after being heated to a certain state, the thermal grease becomes semi-fluid and fills the gap between the CPU and the heatsink, making the bond between them tighter and enhancing heat conduction. Normally, thermal grease is insoluble in water, not easily oxidized, and has certain lubricity and electrical insulation properties. Like thermally conductive silicone grease, thermally conductive silicone is also made by adding certain chemical ingredients to silicone oil and undergoing chemical processing. However, unlike thermal grease, there is some kind of sticky material in the chemical material added to it, so the finished thermally conductive silicone has a certain adhesive force. The most important feature of thermally conductive silicone is that it is hard after solidification, and its thermal conductivity is slightly lower than that of thermally conductive silicone grease.
Cutting fluid: Silicone oil is added to the cutting fluid to play the effect of lubrication as well as defoaming.
Mold release: Because of the non-stick with rubber, plastic and metal, silicone oil can be widely used as a mold release agent for molding and processing of various rubber and plastic products, the advantage of which is that it is easy to release and make the surface of products clean, smooth and clear texture.
4、Medical and food industry
Most of the commonly used medical silicone oil is polydimethylsiloxane, which can be used as antifoaming tablets for abdominal distension and aerosol for pulmonary edema, as an anti-adhesive to prevent intestinal adhesion in abdominal surgery, as an antifoaming agent for gastric juice in gastroscopy and as a lubricant for some medical surgical instruments.
Silicone oil can also be used as a silicone defoamer for the food industry, food-specific polysiloxane resin after emulsification with its products, other are directly available in oil-based products, such defoaming occasions include fermentation and sugar production, as well as other food production process foam suppression.
Silicone grease is an organic silicon grease made by thickening food grade silicone oil with inorganic thickening agent and refined with various additives such as antioxidant and anti-corrosion. Food grade silicone grease is designed for sealing lubrication of food processing equipment. It does not contain any toxic substances and heavy metals, and is absolutely safe for food.
Silicone grease paper is a commonly used wrapping paper with a three-layer structure, the first layer is the base paper, the second layer is the lamination, and the third layer is silicone grease. Since silicone oil paper has the characteristics of high temperature resistance, moisture-proof and oil-proof, it is generally used for packaging in food industry.
5、Surface treatment
It is mainly used for waterproof and anti-fouling of glass fiber materials, with excellent waterproof performance. After the silicone oil treatment, the construction material can improve its wind corrosion resistance and water repellency. In the mortar mixed with 0.1% to 0.15% (mass fraction) or higher solids content of silicone oil emulsion, can show the above characteristics, and can improve the ease and fluidity of mortar. Asbestos, cement, gypsum board, etc. can also be treated with silicone oil.
6、Antifoaming agent
Silicone oil used as antifoaming agent in the field of application is extremely wide.
In the textile printing and dyeing process sections, such as sizing, desizing refining, bleaching and dyeing added as defoamer; in the petrochemical industry, drilling, oil and gas separation, emulsion breaking, oil refining section, as well as lubricants, cutting fluids added to use; in the paper industry and coatings and inks used; in the detergent industry silicone defoamer; and in the aforementioned food industry used silicone defoamer.
7、Other applications
In addition, silicone oil can also be used as a variety of additives for silicone rubber, coating leveling agent, anti-static agent, surfactants, etc., widely used in daily life and industrial manufacturing in many fields.
