Preparation and performance of high refractive index silicone resin‐type materials for the packaging of light‐emitting diodes

Abstract

A novel high refractive index and highly transparent silicone resin-type material for the packaging of high-power lightemitting diodes (LEDs) is introduced, which was synthesized by hydrosilylation of vinyl end-capped methylphenyl silicone resin and methylphenyl hydrosilicone oil catalyzed by Karstedt's catalyst. The vinyl end-capped methylphenyl silicone resins were prepared by hydrolysisÀpolycondensation method from methylphenyl diethoxysilane (MePhSi(OEt) 2 ), phenyl triethoxysilane (PhSi(OEt) 3 ), and vinyl dimethylethoxy silane (Me 2 ViSiOEt) in toluene/water mixture catalyzed by cation-exchange resin. The vinyl end-capped methylphenyl silicone resins were characterized by 1 H-NMR and Fourier-transform infrared. The performances of the cured silicone resintype materials for LED packaging have been examined in detail.

Synthesis of vinyl end‐capped polydimethylsiloxane by ring opening polymerization of octamethylcyclotetrasiloxane (D4) catalyzed by rare earth solid super acid SO42‐/TiO2/Ln3+

“…To discuss the polymerization mechanism, the influence of polymerization time on the ring opening polymerization of D4 without the end‐capped reagent was investigated at 80 °C. Table illustrates that both polymer yield and M n increased with prolongation of the polymerization up to 6 h. A longer reaction time results in lower molecular weight and broader molecular weight distribution after polymerization at 80 °C for 12 h. It can be concluded that ring opening polymerization of D4 catalyzed by SO 4 2− /TiO 2 /Nd 3+ is also an equilibrium reaction and the products can be degraded through ‘back‐biting’ reactions …”

“…According to the literature, SO 4 2− binds to the metal ions in the rare earth solid super acid in the chelating bidentate form, and due to the strong attraction of electrons from the metal ions through two covalent S=O bonds the central metal atom is severely electron‐deficient, resulting in strong Lewis acidity. When a Lewis acid site absorbs water, it is converted to a Brønsted acid site (Scheme ).…”

“…Ln 2 O 3 was obtained from Shanghai Yaolong factory (Shanghai, China). The rare earth solid super acid SO 4 2− /TiO 2 /Ln 3+ was prepared according to the method of Yang and colleagues . As an example (Table , run 1), 10 g TiO 2 .H 2 O was immersed in 25 mL immersing solution with [Ln 3+ ] = 0.05 mol L −1 and [SO 4 2− ] = 1.85 mol L −1 , and then the rare earth solid super acid was calcined at 500 o C for 3 h in a muffle furnace.…”

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

“…Epoxy resins have typically been used as packaging materials owing to their characteristics of excellent sealing, high insulation resistance, and good mechanical properties. However, with the increase of LED device power, the respective shortcomings of epoxy resins such as low thermal stability against yellowing were revealed gradually, which is unable to meet the requirement of the high‐power white LED encapsulants . Owing to the high transmittance as well as excellent thermal resistance, silicone resins have currently been considered to be an outstanding packaging material.…”

Research of the Dispersity of the Functional Sericite/Methylphenyl- Silicone Resin

“…The synthesis, modified method of the silicone resin as high performances composites is studied, such as nano-particle [10,11] and fiber reinforced [12,13], stem grafting [14], polymerize [15], crosslinking [16]. Especially, nano- particle reinforces silicone resin composites.…”