Synthesis of an adhesion‐enhancing polysiloxane containing epoxy groups for addition‐cure silicone light emitting diodes encapsulant

Abstract

Addition-cure silicone resin is considered as a good choice for light emitting diodes (LEDs); however, it has very poor adhesion to the substrate, which limits its practical application. A novel polysiloxane with self-adhesion ability and higher refractive index for the encapsulating of high-power LEDs is prepared and characterized. This polysiloxane containing vinyl groups, phenyl groups, and epoxy groups was synthesized by a sol-gel condensation process from methacryloxy propyl trimethoxyl silane, γ-(2,3-epoxypropoxy)propytrimethoxysilane, and diphenylsilanediol under the catalysis of an anion exchange resin. Then, the resin-type encapsulation material was prepared by hydrosilylation of methylphenyl hydrogen-containing silicone resin and the newly synthesized polysiloxane material. The novel polysiloxane was characterized by 1 H-NMR and Fourier transform infrared spectroscopy. On the basis of higher refractive index, higher transparency, excellent thermal stability, and appropriate hardness, as well as good adhesive strength between the encapsulating material and the LED lead frame (polyphthalamide), the curable silicone resin-type encapsulation material can be used as an encapsulant for LEDs.

Preparation of ZrO2/silicone hybrid materials for LED encapsulation via in situ sol‐gel reaction

“…The methoxy‐functionalized oligosiloxane was synthesized using a nonhydrolytic sol–gel condensation of VTMS, MPTMS, and DPSD (1:1:2 molar ratio) according to our previous reports . The monomers and Ba (OH) 2 ·H 2 O (0.15 mol% of the total monomers) as a basic catalyst were mixed and kept stirring at 80°C for 24 hours.…”

Preparation of high‐performance epoxy‐containing silicone rubber via hydrosilylation reaction

“…Thus, improving the compatibility is the key to matrix modification. Several groups have studied the modification of PDMS with epoxy resin or epoxy compounds . The addition of epoxy copolymer to PDMS is considered as an effective way to improve the compatibility.…”

High refractive index adamantane‐based silicone resins for the encapsulation of light‐emitting diodes

“…During the process of lighting in LED devices, a majority of electrical energy converts into thermal energy because of invalid recombination, so that the electrical packaging materials withstood higher temperature which can reduce the performance of LED chips. It is important that LED encapsulants have excellent thermal stability . Thermogravimetric analysis (TGA) measurement in nitrogen was used to estimate the thermal stability of the cured samples in terms of thermal decomposition.…”