Research And Application Of Liquid Silicone Rubber For High-power Light-emitting Diode Encapsulation

Light Emitting Diode has many advantages,such as energy saving,high efficiency,environmental protection.It is gradually replacing the traditional lighting source as a new generation of green lighting,and is widely used in various industries.But with the improvement of LED brightness,power and luminous efficiency,the encapsulation materials put forward higher requirement in light transmittance,refractive index and anti-aging performance.Silicone encapsulation materials with high refractive,high transmittance,excellent resistance to UV and anti-aging properties,and is the ideal high-power LED packaging materials.It becomes a hot research at home and abroad.Hydroxyl-terminated polymethylphenyldimethoxysilane(PMPS)was synthesized from methylphenyldimethoxysilane by hydrolysis polycondensation method,and the structure of products was characterized by IR and 1HNMR.The influences of reaction factors were investigated,and the optimum reaction conditions were as follows: the amount of benzenesulfonic acid was 0.1%,the reaction time was 7h,the reaction temperature was 65 ℃.Methylphenylvinylpolysiloxane(VPMPS)was prepared by using hydroxyl-terminated polymethylphenyldimethoxysilane and tetramethylvinyl ethoxysilane as raw materials.The influences of synthesis process such as catalyst,reaction temperature and reaction time were studied,the optimal synthesis conditions were as follows: the reaction catalyst was LiO H,the amount was 2%,the reaction temperature of the first stage was 88 ℃,the reaction time of the first stage was 4h,the reaction temperature of the second stage is 140 ℃,the reaction time of the second stage is 4h.Phenylhydropolysiloxane HC-1,HC-2 and HC-3 with different functionalities were synthesized from phenyltrimethoxysilane,diphenyldimethoxysilane and phenyltrichlorosilane as raw materials and the structure was characterized by IR and 1HNMR.The compatibility with methylphe nylvinylpolysiloxane was tested.Liquid silicone rubber was prepared by using phenylhydropolysiloxane HC-1 and HC-3 as cross-linkers,methylphenylvinyl as polysiloxane-based polymers,HC-2 as chain extenders,platinum-based complex as catalysts.The effects of phenylhydropolysiloxane with different functionalities on the optical properties of liquid silicone rubber were studied.The results showed that liquid s ilicone rubber prepared with phenylhydropolysiloxane HC-1 as crosslinking agent had the best light transmittance(93.5%)and refractive index(1.57).This Liquid silicone rubber might be applied in the high-power light-emitting diode encapsulation.