Preparation and properties of silicone -cycloaliphatic epoxy resins for LED packaging

摘要

Silicone-cycloaliphatic epoxy resins were successfully synthesized by a two-step reaction route: (i) hydrosilylation of 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) and 2-epoxy-4-vinyl-cyclohexane,and then blocking of unreacted Si-H with n-butanol, (ii) In order to reduce the viscosity, different amounts of active diluent(Allyl Glycidyl Ether) was added into (i). The molecular structures of the hydrosilylation of 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) were characterized by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H NMR). The results show that active diluent plays an important role in the silicone -cycloaliphatic epoxy resins for LED packaging. Compared with the pure silicone-cycloaliphatic epoxy resins, the silicone-cycloaliphatic epoxy resins with 5 phr of active diluent had higher initial decomposition temperaturwere. Mechanical property tests show that the tensile strength of the silicone -cycloaliphatic epoxy resins with 5 phr of active diluent are 10.1MPa which increases by 114.38% compared with that of the neat silicone -cycloaliphatic epoxy resins, and the elastic modulus of increases by 119.54%. Moreover, the characteristics of transmittance of the silicone -cycloaliphatic epoxy resins with 5 phr active diluent(>95%, 400-800 nm) was better than that of the neat silicone -cycloaliphatic epoxy resins. The shore hardness and impact toughness of the silicone-cycloaliphatic epoxy resins provide good performance. The pendulum impact test shows that the silicone -cycloaliphatic epoxy resins with 10 phr of active diluent reaches 2.3KJ/m2. The shore hardness of the silicone - cycloaliphatic epoxy resins with 20 phrof active diluent reaches 80D.