Study On The Preparation And Performance Of Polysiloxane-modified Epoxy Resin For LED Encapsulation

Semiconductor light-emitting technology assembled by light emitting diode(LED)has got advantages over high brightness,low power consumption,long life than other ones.With the development of LED chip technology,traditional epoxy resins applied as packaging materials has been unable to satisfy the demands of power LED packaging.Therefore,the research on silicone modified by epoxy resin for LED encapsulation,which possess many advantages over epoxy resins and silicone materials,were carried out by researchers all over the world.In this paper,the research development of silicone modified by epoxy resin for LED encapsulation was discussed in detail.A series of epoxy resin modified by polysiloxane were designed and synthesized.The performance and application in LED packaging were investigated in this paper.The main work in this paper were as follows:Part 1: Methylpolysiloxane modified by epoxy resin(D4~H-VCHO)was synthesis via hydrosilylation by 1,3,5,7-tetramethyltetrahydrocyclosiloxane(D4~H)and 4-vinyl-1-cyclohexene-1,2-epoxide(VCHO).The synthesis process of D4~H-VCHO was discussed and optimized.The optimal results were showed as follows: the epoxy value was 0.541;the refractive index was 1.4920;and the viscosity was about 350 mpa.s.Part 2: A series of highly transparent methyl phenyl polysiloxane modified by epoxy resin(PhSi-VCHO)was synthesized by the hydrosilylation of 4-vinyl-1-cyclohexene 1,2-epoxide and methyl phenyl hydrogen silicone intermediates which were homemade.The synthesis process of PhSi-VCHO was discussed and optimized.The optimal results were showed as follows: the epoxy values were adjustable from 0.23 to 0.42,the refractive indexes were adjustable from 1.48 to 1.52,and the viscosities were between 1000-1200 mpa.s.Part 3: LED packaging materials were prepared by using those synthesized polysiloxane modified by epoxy resin(D4~H-VCHO),methylphenylpolysiloxane modified epoxy resin(PhSi-VCHO).The performance of D4~H-VCHO packaging materials materials were showed as follow: the refractive index were over 1.4861,the hardness were above 90 Shore D,the water absorption were 0.08%.And the performance of PhSi-VCHO packaging materials were showed as follow: the refractive indexes were adjustable from 1.48 to 1.52,the harnesses were more than 85 Shore D,the water absorptions were between 0.09-0.13%,their transmittance were all above 90%,and both of D4~H-VCHOand PhSi-VCHO packaging materials exhibited good properties,such as thermal stability,adhesion and aging resistance.Part 4: The non isothermal and isothermal DSC were used to study on the curing behavior of polysiloxane modified by epoxy resin/anhydride.The curing kinetic parameters were calculated through the kinetic equations which were as follow: the starting temperature(Ti),peak temperature(Tp),peak end temperature(Tf)were 61 ?,100 ?,142?;the gel curing time at 110 ? was 13minutes;the apparent activation energy was-65.875 KJ/mol;the reaction order n was 0.91;the final curing degree was 0.97 which need 35 minutes.