Performance characteristics and comparison of cycloaliphatic epoxy resins in LED packaging materials

LED (Light Emitting Diode) devices have the advantages of high efficiency,low power consumption,and high durability,and are widely used in applications such as large-size displays,traffic signals, and lighting,With the rapid development of LED application technology,the performance requirements for packaging materials are also getting higher.

Thermal curing epoxy resin has good mechanical properties,low curing volume shrinkage,excellent adhesion to substrates,and strong controllability of operating processes.It is one of the important packaging systems for LEDs at present.Among them,cycloaliphatic epoxy resins,especially 3,4-epoxycyclohexyl-3,4-epoxycyclohexyl ester (TTA21) are preferred due to their excellent processability,high Tg point and good weather resistance It is widely used in LED and optical device encapsulant.

It should be noted that the curing cross-linking strength of alicyclic epoxy resin is very high,and it is easy to crack the cured product due to excessive internal stress,thereby limiting the performance of the product (during the encapsulation process,moisture absorption and mechanical stress are two factors.One of the main factors affecting product reliability,in which mechanical stress is caused by curing stress and cooling stress caused by mismatching coefficients of thermal expansion (CTE), usually in practical applications with bisphenol A epoxy resin (or hydrogenated Bisphenol A epoxy resin) to adjust the toughness of the system.