The Preparation And Properties Of Electrical Encapsulant

With the development of electronic technology, the integration of the electrocircuit becomes very high. If the heat produced by the electronic component can not diffuse quickly, it will affect the performance stability and working life of the electrical equipment. The electrical encapsulant not only can dissipate heat, but also can facilitate moistureproof, dustproof and shockproof. Electrical encapsulant is more and more widely used in electronic products.In this paper, The two components addition-type thermal conductive and insulated electrical encapsulant was prepared using vinyl silicone oil as matrix, hydrogen silicone oil as cross linking agent, Al2O3, A1N and ZnO as thermal conductive fillers, chlorine platinum acid complex as catalyst. The effect of the matrix resin proportion, reinforcement agent, surface treatment of thermal conductive fillers with silane coupling agent, and thermal conductive fillers on encapsulant properties was researched. The effect of fill amount, particle size, mix using of different particle size and different kinds of fillers on the performance of encapsulant was also researched.The viscosity of the encapsulant increased with the increasing mass fraction of the thermal conductive fillers. In the same filling mass fraction, the viscosity of small particle size fillers filling encapsulant is higher than that of large particle size fillers. Hybrid filling of different particle size fillers can decrease the viscosity of encapsulant. Surface treatment of thermal conductive fillers with A-151before filled into encapsulant, can also decrease the viscosity.The larger the filling fillers’particle size is, the easilier the encapsulant may settle. The thermal conductive fillers have good compatibility with silicone rubber resin after treated by silane coupling agent of A-151, and the sedimentation rate of encapsulant is low. When the viscosity of encapsulant is low, it will settle easily.The thermal conductivity of the encapsulant improves with the increasing mass fraction of the thermal conductive fillers. The thermal conductivity of large particle size fillers filling encapsulant is higher than small particle size fillers. Hybrid filling of different particle size fillers can improve the thermal conductivity of encapsulant. Mix filling of different kinds of fillers can also improve the thermal conductivity. After surface treated by silane coupling agent, the thermal conductive fillers have good compatibility with silicone rubber resin, which can make the thermal conductivity of encapsulant improve.The tensile strength of encapsulant increases with the fill amount increasing, then decreasing when the filling mass fraction is more than80%. The tensile strength of small particle size fillers filling encapsulant is higher than big particle size. Hybrid filling of different particle size fillers can improve the tensile strength of encapsulant.ZnO rod was synthesized by hydrothermal synthesis method, and mixing filling with Al2O3to prepare encapsulant, which can increase the thermal conductivity and tensile strength, and decrease the viscosity of encapsulant.The two components addition-type thermal conductive and insulated encapsulant with excellent performance was expanded prepared using vinyl silicone oil as matrix, hydrogen silicone oil as cross linking agent, Al2O3and rod ZnO as thermal conductive fillers, chlorine platinum acid complex as catalyst and dual planet mixer as mixing equipment. The thermal conductivity is1.63W·m-1·K-1, the viscosity is20000mPa·s, the tensile strength is1.95MPa, the Shore hardness is74, the volume resistivity is3.7×1014Ω·cm, good heat resistance and without sedimentation.