Abstract
Curingofhydrogenatedbisphenol-AglycidyletherwithanhydridewereinvestigatedasatransparentencapsulantforUVlightemittingdiode(LED).ToreducediscolorationcausedbyUVand/orthermaleffect,chemicalstructureofacceleratecatalyst,cycloaliphaticepoxyresinconcentrationandantioxidantwereexamined.Byusingcatalystwithsmallamountofdoublebond,UVdiscolorationwasdecreased.AscomparedwithconventionalLEDencapsulantofbisphenol-Aglycidylether,thermaldiscolorationwashighandglasstransitiontemperature(Tg)waslow.Additionofcycloaliphaticepoxyresinwith10wt%increasedtheTgtobeover120℃,whichisalmostthesamevalueasconventionalone,butthermaldiscolorationwasstillhigherthanconventionalone.Toimproveresistanceagainstthermaldiscoloration,additionofantioxidantwasstudied・Incaseofphosphorousantioxidant,UVdiscolorationwasacceleratedHowever,whenphenolicantioxidantsuchas2,6-di-tert-butyl-4-mehtyl-phenol(BHT)wasused,thermaldiscolorationwasreducedwithoutincreasingUVdiscoloration.
