Automotive electronics and protective materials-- ...

Automotive electronics and protective materials In addition to the abundant power system driving, the vehicle driving on the road depends on its sensitive and complex control system, so that the vehicle can safely drive under better conditions. The control system is the nerve center of a car, which contains many complex and precise control mechanisms and control modules. It guides the operation of various components by various output, detection, diagnosis, feedback and other information control systems. With the development and combination of automobile industry and electronic industry, various electronic control mechanisms and modules are gradually introduced into the control system to obtain more accurate and agile control, so as to improve the performance of the car.   When driving on the road, the vehicle must bear the erosion of wind, sand, rain, snow, high and low temperature, vibration and other ground-based weather and pollutants. Therefore, all kinds of precise electronic control modules must be protected by appropriate protective materials to ensure its stability and reliability. In the field of automotive electronic application, the selection of protective materials requires not only the characteristics of insulation, moisture-proof, pollution-proof, corrosion-proof and heat conduction, but also the properties of low stress, heat resistance and cold resistance. Because of these properties at the same time, the application of silicone materials in the field of automotive electronics has been paid more and more attention.   Properties of organosilicon Organosilicon is a kind of synthetic polymer with silicon atom and oxygen atom as the main chain. Due to the strong chemical bond of silicon oxygen structure, the molecules of organosilicon polymers are much more stable to heat and oxygen than those of ordinary organic polymers. Although the mechanical properties of organosilicon at room temperature are not different from those of other materials, its physical and mechanical properties at high and low temperature are excellent. The properties of organosilicon polymers are not affected by the multiple alternations of temperature from - 60 ℃ to + 250 ℃. Therefore, organosilicon polymers can be used for a long time in this temperature range. Some organosilicon polymers can be used normally as low as - 100 ℃. Because of the dipole effect in the silicone molecule, it can effectively buffer and weaken the influence of the external electric field, thus protecting the hydroxyl connected to the silicon atom, making it not easy to be eroded by physical factors or chemical agents. The products made of polysiloxane are not only corrosion-resistant, radiation resistant and high and low temperature resistant, but also low moisture absorption, high insulation resistance, low dielectric constant, low stress, vibration reduction, environmental protection, low toxicity, flame-retardant and repairable. Therefore, silicone is made into a variety of adhesive sealants, potting adhesives, insulating coatings, silicone grease and other finished products used in various electronic devices.   Application of organosilicon material in automotive electronics   Silicone applications in automotive electronic devices include adhesives and sealants, potting adhesives, gels, insulation coatings, thermal conductive adhesives and other materials. These materials are used to protect engine control module, ignition coil and ignition module, power system module, brake system module, exhaust emission control module, power system, lighting system, various sensors, connectors, etc.   Bonding and sealant: used in various control modules as the bonding and fixation of components on the circuit board, or auxiliary fixation of large components, such as capacitance, inductance, and coil, to prevent components from falling off due to vibration, with the function of fixation and vibration reduction. In addition, it is also used for bonding and sealing of module shell, which has the functions of sealing, moisture-proof, anti fouling and anti-corrosion. If the thermal conductive adhesive is used, it has the function of bonding and heat dissipation at the same time. It can be used to fix the power device or to bond the heat sink to achieve the function of bonding and heat dissipation. Dow Corning dc7091 has been widely used in the sealing of various control module housings and the bonding of connectors. The bonding between the circuit board and the aluminum heat dissipation shell in the engine control module is a typical application of thermal conductive adhesive. Dow Corning 1-9226 thermal conductive adhesive is very popular.   Potting glue: it is used on all kinds of control modules to make overall and general potting of components to meet the basic requirements of moisture-proof, pollution-proof and corrosion-proof. The silicone potting adhesive can reduce the stress and bear the impact of high and low temperature. For high-power control module, thermal conductive potting glue is used to achieve the function of heat dissipation. Silicone potting materials are widely used in wiper controller and power system module. The encapsulation of HID (high intensity discharge) lamp module is a typical application. The HID module contains the igniter and converter. The potting adhesive used must have good bonding property and excellent dielectric property, be able to prevent dust and water seepage, and play a sufficient insulation protection role; the potting adhesive must be relatively soft, and be able to prevent the solder joint from falling off; because there are some heating elements in the module, the potting adhesive needs to have a certain thermal conductivity role; in order to prevent volatile substances from occurring on the lamp tube and refractor Atomization, potting adhesive is refined; potting adhesive must be UL94V-0 flame retardant grade. It is very suitable for the application of red leaf silica gel hy-215tt two-component potting adhesive in HID module.   Gel: gel encapsulating material is the main adhesive used in automotive electronic devices. Its function is similar to that of potting adhesive, but it can further reduce stress and reduce vibration. It has special function for fine line protection under the condition of bearing vibration and very low temperature. The low stress of silicone gel encapsulating material and the original insulation and moisture resistance of silicone make silicone encapsulating material the main potting protective material in automotive electronics. Protection engine control module and ignition coil are typical applications. And advanced steam and electricity