Flame-Retardant Cycloaliphatic Epoxy Systems with High Dielectric Performance for Electronic Packaging Materials

Flame-retardant cycloaliphatic epoxy systems have long been studied; however, the research suffers from slow and unsatisfactory advances. In this work, we synthesized a kind of phosphorus-containing difunctional cycloaliphatic epoxide (called BCEP). Then, triglycidyl isocyanurate (TGIC) was mixed with BCEP to achieve epoxy systems that are rich in phosphorus and nitrogen elements, which were cured with 4-methylhexahydrobenzene anhydride (MeHHPA) to obtain a series of flame-retardant epoxy resins. Curing behaviors, flame retardancy, thermal behaviors, dielectric performance, and the chemical degradation behaviors of the cured epoxy system were investigated. BCEP-TGIC systems showed a high curing activity, and they can be efficiently cured, in which the incorporation of TGIC decreased the curing activity of the resin. As the ratio of BCEP and TGIC was 1:3, the cured resin (BCEP1-TGIC(3)) showed a relatively good flame retardancy with a limiting oxygen index value of 25.2%. In the cone calorimeter test, they presented a longer time to ignition and a lower heat release than the commercially available cycloaliphatic epoxy resins (ERL-4221). BCEP-TGIC systems presented good thermal stability, as the addition of TGIC delayed the thermal weight loss of the resin. BCEP1-TGIC(3) had high dielectric performance and outperformed ERL-4221 over a frequency range of 1 HZ to 1 MHz. BCEP1-TGIC(3) could achieve degradation under mild conditions in an alkali methanol/water solution. Benefiting from the advances, BCEP-TGIC systems have potential applications as electronic packaging materials in electrical and electronic fields.

Automated summary

In this study, we synthesized a phosphorus-containing cycloaliphatic epoxy resin and achieved flame-retardant epoxy resins by curing with a mixture of triglycidyl isocyanurate. The cured resins exhibited high curing activity, good flame retardancy, thermal stability, and dielectric performance. They also showed degradation under mild alkaline conditions. These findings suggest potential applications of the BCEP-TGIC systems in electronic packaging materials.