The Research Of LED Encapsulating Silicone Rubber And Adhesive Property

The methyl-tackifier was synthesized using hydrolysis by blending methyltrime-thoxysilane, dimethyldimethoxysilane,3-Glycidoxypropyltrimethoxysilane (KH560),methacryloxypropyltrimethoxysilane (KH570) and tripropyl borate, takinghydrochloric acid as catalyst. Here we chose the methyl vinyl MQ resin withM/Q=0.8-1.0, solid content control in50percent, vinyl content2-3%, and viscosity5000-7000cs as precursor. The LED encapsulating silicone rubber consist ofhydrosilicone oil, methyl vinyl MQ resin and tackifier. And this rubber could achievegreat improvement of the adhesiveness between PPA (Polyphthalamide) and metalAg, without deteriorating the mechanical properties and transmittance, by optimizingthe ratios of hydrosilicone oil, methyl vinyl MQ resin and tackifier. We performedresearch to investigate the properties of mechanical, transmittance, ink penetrationresistance, thermal resistance, hot and cold shock resistance, suitability and reliabilityof methyl-silicone rubber. The testing results with hardness70A, mix viscosity4000cs indicated that the excellent properties of the methyl-silicone rubber can meet therequirement of LED encapsulating. Due to the higher hydrogen content ofmethyl-silicone rubber would reduce it tear strength. Therefore, the goodmechanical properties would be reserved when we kept its hydrogen content at therange of7.5-8.0mmol/g. Under this condition, the silicone rubber could achievetensile strength in7.5Mpa, elongation at150%, and96%transparency. By applyingour silicone rubber for encapsulating in high power LED, the optical power can beimproved obviously.The phenyl-tackifier was synthesized using hydrolysis by blending diphenyld-imethoxysilane, dimethoxymethyl-phenylsilane, acidic sols containing polymer ofpoly (methyl phenyl siloxane),3-Glycidoxypropyltrimethoxysilane (KH560),methacryloxypropyltrimethoxysilane (KH570) and tripropyl borate, takinghydrochloric acid as catalyst. Here we chose the phenyl vinyl silicone resin with vinylcontent5-6%, and viscosity8000-12000cs, refrective index1.54as precursor. The LED encapsulating silicone rubber consist of phenyl hydrogen silicone resin, phenylvinyl silicone resin and phenyl-tackifier. And this rubber could achieve greatimprovement of the adhesiveness between PPA (Polyphthalamide) and metal Ag,without deteriorating the mechanical properties and transmittance, by optimizing theratios of phenyl hydrogen silicone resin, phenyl vinyl silicone resin andphenyl-tackifier. We performed research to investigate the properties of mechanical,transmittance, ink penetration resistance, thermal resistance, hot and cold shockresistance, suitability and reliability of methyl-silicone rubber. The testing results withhardness30D, mix viscosity5500cs and refractive index1.54indicated that theexcellent properties of the phenyl-silicone rubber can meet the requirement of LEDencapsulating. Due to the higher hydrogen content of phenyl-silicone rubber wouldreduce it tear strength. Therefore, the good mechanical properties would be reservedwhen we kept its hydrogen content at the range of2.5mmol/g, the refractive index1.54and viscosity1200cs. Under this condition, the silicone rubber could achievehardness30D, mix viscosity5500cs and refractive index1.54,97%transparency. Byapplying our silicone rubber for encapsulating in high power LED, the optical powercan be improved obviously.