Research On Preparation And Properties Of High Performance LED Encapsulation Materials

With the improvement of brightness and efficiency of light emitting diode (LED), especially high brightness LED chip dramatically progressed recently, the preparation of the encapsulation materials has become an important key technique for LED lighting used in our daily life.Integration of integrated circuit improve more higher, as well as more high-tech methods used in the industry, there are more strict requirements to the performances of the package materials. For example, the short curing time, heat resistance, little ion and impurity content. Silicone materials, which have high temperature resistance, excellent weather resistance and hydrophobicity, have been widely used in the fields of aviation, electronic equipment and encapsulation. Epoxy resin has drawn much attention used as the electronic packing materials, due to its excellent insulation, adhesive, chemical resistance and better processability. The fact that there was no aromatic group in the molecular of cycloaliphatic epoxy endowed the resin with the capacity to resist the ultraviolet and the carbonization caused by the arc. Cycloaliphatic epoxy-silicone resin has the advantages of aliphatic epoxy resin and silicone resin, which has become the mainstream in the development of IC packaging materials in twenty-first Century.(1) Methyl alicyclic epoxy-silicone resin was prepared by 4-vinyl epoxy cyclohexane and methyl hydro-silicone under the triphenyl phosphorus platinum chloride catalysis. Optimum preparation technological conditions were obtained by changing the reaction conditions: quality ratio of 1:1.7. the reaction temperature 100 ?. dosage of catalyst 0.4 g. FT-1R and 'H-NMR methods were used to characterize the structure of products, and the transmittance performance test was carried on.(2) Phenyl hydro-silicone was prepared by using trimethoxy silane. diphenyl dimethoxy silane, 1,1,3,3-tetramethyl-1,3-dihydrodisiloxane as main materials, water and toluene as a solvent and concentrated sulfuric acid as catalyst. The structure of product was characterized by FT-IR and 'H-NMR. Then, the phenyl alicyclic epoxy-silicone resin was prepared by using phenyl hydro-silicone and 4-vinyl epoxy cyclohexane as materials, and the structure and properties were characterized. The results showed that the transmittance of the anhydride and UV cured products was better than that of the amine and the UV curing time was shorter. The curing kinetics of epoxy silicone resin/anhydride system was studied by DSC method, which provided a theoretical basis for the determination of the curing process.(3) Vinyl-terminated polydimethylvinylsiloxanes (Vi-PViMS) with low RI were firstly prepared by anionic ring-opening polymerization of octamethylcyclotetra-siloxane (D4), tetravinyl tetramethylcyelo tetrasiloxane (D4Vi) and diethenyl-1,1,3,3-tetramethyldisiloxane (MMVi). Their chemical structures and performance were characterized. The effects of synthesis conditions, the ratio of raw materials and the amount of catalyst on the refractive index, yield, viscosity and transmittance of the products were studied. Then epoxidation reaction of multi vinyl silicone was investigated, carboxylic acid metal phthalocyanine complex and 30% H2O2 used as epoxidation reagent, then alicyclic epoxy-silicone resin was prepared, research shows that the introduction of a small amount of epoxy group better improve its refractive index.