Synthesis And Properties Of Zr/Al-containing Hybrid Silicone Resins

Silicone resin has excellent thermal stability,weather resistance,electrical insulation and other characteristics due to its unique structure.It is widely applied in aerospace,electronic devices and other fields.With the development of high-power LED packaging technology,traditional packaging materials cannot meet the performance requirements as their low refractive index and poor temperature resistance.Metal-hybrid silicone resin is a kind of organic-inorganic hybrid material.It combines the excellent characteristics of metal elements and silicone resin,which provide it the higher refractive index,good heat resistance and better light transmittance.The focus of this paper is to respectively synthesize zirconium,aluminum,zirconium/aluminum hybrid silicone resins,and prepare solid/cross-linked materials.It can ensure the service life and light extraction efficiency of LEDs.The structure and performance of liquid/solid silicone resins were studied.Starting from alkoxysilanes and metal precursors as raw materials,Zr-,Al-,Zr/Al-containing hybrid resins were synthesized by co-hydrolysis and co-condensation which contains either Si-O-Zr or Si-O-Al bond or both.FTIR,NMR,SEM had been used to characterize the structure and the refractive index,light transmission,thermal stability,water resistance,wear resistance,adhesion and dielectric properties were studied.(1)Zr-containing hybrid resins(ZSRs):With the increase of zirconium content,the degree of polycondensaton increased;the surface of the sample was smooth without obvious agglomeration and phase separation;when 50mol%Ph,Zr/Si=15mol%,the refractive index reached 1.5206;the transmittance in the range of 500-1 000nm was as high as 90%,the wear resistance was high as 4H,and the adhesion reached 1 level;ZSR had good heat resistance.(2)Al-containing hybrid resins(ASRs):It contained a small amount of ring structure,mainly linear or branched structure.The surface roughness of the coating was low,no agglomeration and phase separation,the actual incorporation of aluminum isopropoxide was 70%-80%.When 60mol%Ph,Al/Si=30mol%,refractive index was up to 1.5307,Hardness was high as 82A,pencil hardness was 2H,the coating transmittance was as high as 97%.The contact angle was reduced,and the water absorption rate was increased,but it was still a hydrophobic material,and the dielectric constant was increased.It can be used at 150? for long time.(3)Zr/Al-containing hybrid resins(ZASRs):the surface roughness of the coating was low,without agglomeration and phase separation.The actual incorporation of aluminum isopropoxide was 70%-80%.When 60mol%Ph,the refractive index of ZASR20-2:1 was up to 1.5460,and when 60mol%Ph,the refractive index of ZASR30-2:1 was up to 1.5507.The hardness was up to 79A,the pencil hardness was 2H,the adhesion reached level 1,the transmittance of the coating was up to 96%at 500 nm,the contact angle was reduced.and the water absorption rate was increased,but it was still a hydrophobic material,the dielectric constant increased.The heat resistance was improved with the increase of Zr content.The metal hybrid silicone resin has excellent refractive index,light transmittance,thermal stability,water repellency and low dielectric property,which can be used to the LED encapsulation materials.