Which industries are thermally conductive silica gel mainly used in

The traditional method to solve the heat dissipation of electronic equipment is to pad a layer of insulating medium between the heating body and the heat dissipation body as a thermal conductivity material, such as mica, polytetrafluoroethylene and beryllium oxide ceramics, etc. This method has a certain effect, but there are poor thermal conductivity, low mechanical properties and high prices. With the development of industrial production and science and technology, people continue to put forward new requirements for materials. In the field of electronic and electrical appliances, due to the rapid development of integrated technology and assembly technology, electronic components, logic circuits to light, thin, small direction, the heat also increases, so that the need for high thermal insulation materials, effectively remove the heat generated by electronic equipment, which is related to the service life of the product and quality reliability.
　　At present, some of the solutions to the heat dissipation of electronic devices are solved by various forms of heat sinks, but most must be solved by thermal conductive materials, thermal silicone thermal conductive materials are an important member of the thermal conductive materials. The following is to introduce the types of thermal conductive silica gel thermal materials, and put forward some application solutions for thermal conductive products.
　　1, the mechanism of thermal conductivity of silicone thermal materials
　　Thermal conductive silica gel Thermal conductive material is a typical polymer composite material, and its thermal conductivity is mainly determined by the type of thermal conductive filler and the distribution of thermal conductive filler in the silicone rubber matrix. Metal fillers (such as Al, Ag, etc.) have high thermal conductivity, but most are thermal and conductive; Inorganic non-metallic materials (such as AlN, SiC, etc.) also have high thermal conductivity, but the price is quite expensive; At present, the main use of metal oxides (such as Al2O3, ZnO, etc.) as thermal conductivity filler, the following figure is the thermal conductivity of thermal silicone sheet (JRF-PM500). The thermal conductivity mechanism of various filling materials is different, metal materials mainly rely on electronic movement for heat conduction, metal thermal conductivity decreases with the increase of temperature, the thermal diffusion speed of non-metal mainly depends on the vibration of neighboring atoms and binding groups, in the strong covalent bonded materials, in the ordered crystal lattice heat conduction is more efficient. Therefore, when using non-metallic materials as thermal conductivity fillers, how to improve the thermal conductivity "stacking degree" in the system is the main means to improve the thermal conductivity.

2, the type and application of thermal conductive silicone thermal materials
　　Heat-conducting flame retardant silicone rubber material
　　In recent years, silicone rubber material has been widely used in the electronic and electrical industry, but because it is a polymer material, flammable, large smoke, sometimes it is the direct fuse of fire; Therefore, flame retardant silicone rubber has slowly become the main force of silicone rubber materials in the electronic and electrical industry. The company uses the surface treated thermal conductive filler and homemade flame retardant to develop a flame retardant UL94V-0 level, thermal conductivity of more than 1.0W/m·K(are tested and certified by the authority) SKF323 thermal retardant silicone sealant products. It is now widely used in electronic and electrical products such as automotive modules, circuit modules and PCB boards with high thermal conductivity and flame retardant requirements.
　　Heat-conducting and heat-resistant silicone rubber
　　Thermal conductivity and high temperature silicone rubber is mainly used in bonding and sealing of low voltage and high current transformers; Heat conduction and insulation of radar magnetic field coil; Assembly of various high temperature power tubes, radiators and printed boards; Micro-packaging technology, electrical appliances and military electrical appliances and other high temperature radiator.
　　Thermal silicone gasket and thermal grease
　　Thermal silicone gasket is a sheet thermal insulating silicone rubber material processed by a special production process. It has the characteristics of natural surface viscosity, high thermal conductivity, high compression resistance, high buffering and so on. It is mainly used in the gap filling material of heating devices and heat sink and casing, because of its soft material and elastic variable under the action of low pressure force. It can be constructed on the surface of the device or even for the rough surface to close contact, reduce the air thermal impedance, a good solution to the thermal grease at high temperature thermal grease is a mechanical mixture of silicone oil and thermal filler, with the characteristics of shaping at any time, high thermal conductivity, no curing, no corrosion to the interface material. In electronic equipment, there are many contact surfaces and assembly surfaces between various electronic components, and there are gaps between them, resulting in poor heat flow. In order to solve this problem, thermal grease is usually filled between the contact surfaces, and the flow of thermal grease is used to exclude the air between the interface and reduce or even eliminate thermal resistance. After the silicone oil seepage, the surface accumulated dust and so on shortcomings.
　　Heat-conducting potting silicone rubber material
　　Potting can be divided into local potting and whole potting. Local potting is only to potting high-power devices, so that it is connected with the heat dissipation body through the thermal potting material, so that the heat generated can be quickly transferred to the heat dissipation body. The overall potting is to potting all the components on the printed circuit board, so that the heat generated can be rapidly diffused and directly distributed to the external environment. Such products are generally two-component, the use of the two components mixed after the bubble, filling on the circuit board, vulcanized into an elastomer, such products not only have heat insulation, but also shock absorption and three defense role, is now widely used in LED lights filling and bonding, other circuits, household appliances insulation seal.
　　High thermal conductivity silicone rubber adhesive
　　High thermal conductivity adhesive (single-component adhesive) is mostly used in insulating occasions, because in the development of the electronic and electrical industry, the field of electronic and electrical materials is in urgent need of thermal conductivity insulation materials, especially in high-power heat dissipation occasions, such as the bonding of semiconductors and radiators, the protection of tube cores, the sealing of tube shells, electronic rectifiers, and the thermal insulation of thermistors. Thermal insulation adhesives with different process properties are required for the thermal insulation assembly of multi-layer panels in micro-packaging.
　　3. Summary
　　Thermal conductive silicone thermal materials in foreign research is more mature, such as Dow Corning, GE Toshiba and so on have developed a variety of thermal silicone rubber products, while the domestic is still in the development stage, only JRF, Thailand and other developed a variety of thermal silicone rubber products, and widely used in various industries. In short, thermal conductive silicone rubber not only has good thermal conductivity, but also has many properties that other materials do not have, such as weather resistance, adhesion, etc., and will be more and more widely used.