Preparation And Characterization Of Zirconium Containing Phenyl Silicone Resin And Sulphur Containing Epoxy Resin For LED Encapsulation

LED packaging materials as a protective layer of chip and gold welding line,can be used as optical lens to improve the luminous efficiency of the chip.High refractive index and high light transmittance encapsulation materials of LED greatly attracted researchers’attention in recent years.Three aspects to increase the material’s refractive index were studied in this thesis:Direct synthesis of zirconium containing phenyl silicone resin,pre-condensed nano particles filled nano-composites,synthesis of sulphur containing epoxy resin.The main works are as follows:（1）Zirconium containing phenyl silicone resin were synthesized through hydrolysis among zirconium n-propoxide（ZP）,diphenyldimethoxysilane,and 3-（trimethoxysily）propyl methacrylate via hydrolytic condensation reaction.Studies show that TPO is the optimal UV initiators.Considering the affection of processing performance and viscosity,the ZP and DMDPS loading in a workable package are limited to about 15mol%and 60mol%.FT-Raman spectra and ²⁹Si nuclear magnetic resonance（NMR）spectra were used to study the structure and degree of condensation of the resins;the results indicated that the resins have the characteristics of linear or branched chains,and the degree of condensation of more than 80percent.Atomic force microscope observation shows that the solidified material has surface roughness<5nm;TGA tests indicated that the resins have favorable thermal stability for practical usage,and the thermal weightless of all resins are less than 3%under 200℃.The refractive index of the materials is positively correlated with zirconium content,and tunable between 1.57 and 1.59,and light transmittance does not change significantly with the increase of zirconium element.In addition,the resins can be stably stored for more than 6 months.（2）TiO₂,ZrO₂ and TiO₂-ZrO₂ gel were prepared by hydrolysis.Studies showed that the optimum addition was 10%for all the three kinds of gels.The addition of ZrO₂ gel nearly does not affect the light transmittance of the packaging material;However,adding of TiO₂colloid will significantly decrease the light transmittance of composites when the light wave length is more than 380nm;light transmittance of composites with TiO₂-ZrO₂ gels is fall in between that of ZrO₂ gel and TiO₂ colloid.The test results showed that the surface of composites is smooth and cross section other than pure resin,the thermal stability of the composites increase under the use temperature（150℃）of packaging materials.End capping agent of divinyl tetramethyl disiloxane（DVTMDSO）is used to adjust the resin viscosity.The optimal addition of DVTMDSO is 0.01mol.（3）Diglycidyl ether of thiodiphenol（DGETP）was synthesized using two-step method with the yield of 74.4%.It is a milk-white solid at room temperature,changed to pale yellow liquid while heating,with refractive index of 1.6000,epoxy value of 3.62 mmol/g.The epoxy has a melting range from 30.4℃to 45.3℃and melting peak of 43.4℃;Using amino-terminated polyoxypropylene（D400）as curing agent,DGETP/D400 and E51/D400were prepared,respectively.The results showed that DGETP/D400 has low glass transition temperature（T_g）of 40.8℃.The light transmittance of DGETP/D400 is lower than that of E51/D400;both are more than>80%in the visible light region.The refractive index of DGETP/D400 after curing is 1.5788,higher than 1.5530 of E51/D400.