With the rapid development of electronic products, the precision of electronic products has been continuously improved, and many electronic components will generate a lot of heat during use. If this heat is not dissipated in time, it is easy to cause high temperature and overheating of electronic components, resulting in failure and affecting electronic and electrical products. service life.
Therefore, efficient heat dissipation has become the focus of the design, especially on chip processors, LEDs, and power packs. In order to solve this problem, electronic thermal conductive potting compound is generally poured into electronic products as a thermal conductive material, so as to efficiently conduct the heat inside the electronic product to the heat dissipation shell, thereby improving the safety and service life of the electronic product.
There are generally three kinds of potting compounds suitable for pouring on electronic components, namely: epoxy resin potting compound, polyurethane material potting glue and silicone material potting glue (here we call it electronic thermal conductivity potting). Plastic closures). Among them, the most suitable for potting in electronic products is silicone potting compound, because other materials have some unavoidable defects.
The potting compound of epoxy resin material has weak resistance to cold and heat changes. Once it is impacted by cold and heat, the colloid will crack, and moisture such as rainwater and condensation will easily penetrate into the electronic components through the cracks, resulting in electronic components. The device is disconnected, which seriously affects the use of electronic products. Polyurethane potting glue, because of its high toxicity, is easy to cause allergic symptoms, so it is necessary to pay great attention to the production and production.
The silicone-based potting compound has excellent electrical properties and insulating properties. It can be used in electronic components to ensure that the components will not interfere with each other, which can effectively improve the stability of electronic products, and can also play a role in thermal conductivity and flame retardant. , Waterproof and shockproof.
Under normal circumstances, the indicators for measuring electronic thermal conductive potting compounds mainly include the following aspects:
Firstly: Thermodynamic properties – thermal conductivity
Thermal conductivity is an important parameter to measure the thermal conductivity of thermally conductive materials. The higher the thermal conductivity, the better the thermal conductivity and heat dissipation effect, and the heat generated by the components can be quickly dissipated. When other conditions are constant, the higher the thermal conductivity, the better the electronic thermal conductive thermal potting compound.
Secondly: Electrical Properties – Dielectric Strength, Volume Resistivity and Dielectric Constant
Of the three properties of interest are dielectric strength (sometimes also expressed in terms of breakdown voltage) and volume resistivity.
Dielectric strength is a measure of the electrical strength of a material as an insulator. It is defined as the maximum voltage a unit thickness can withstand when a specimen is broken down, expressed as volts per unit thickness. The greater the dielectric strength of a substance, the better its quality as an insulator.
Volume resistivity is the resistance of a material to current per unit volume, which is used to characterize the electrical properties of a material. Generally, the higher the volume resistivity, the higher the effectiveness of the material as an electrically insulating component.
The dielectric constant is used to measure the ability to interfere in electromagnetic fields.
Thirdly: Physical properties – fluidity, density and adhesion
Because the electronic thermal conductive potting compound is fluid, it has a certain fluidity, and the popular thermal potting compound can be used to fill the gap with smaller pores and increase the volume of the thermal conduction and heat dissipation contact surface.
Density (specific gravity) is also an indicator of special concern for electronic thermal conductive potting compounds. Generally, under the same thermal conductivity, the lower the specific gravity, the better. The lower the proportion, it is used in industries such as automotive power supply, which can effectively improve energy efficiency.
The electronic thermal conductive potting compound has a certain viscosity, which can firmly bond the heating device and the heat sink together, so the viscosity is also an important indicator to consider the performance of the thermal conductive electronic potting compound.