Development of a new packaging material with superior high-temperature stability is becoming increasingly crucial in high-power and high-density electronics industry. In this study, we employed bis­(3-ethyl-5-methyl-4-maleimidephenyl)­methane (BMI), para-xylene phenolic resin (PF), and triphenylmethane novolac epoxy resin (EP) as matrix resins to develop high-temperature-stable BPE ternary resin molding compounds for power device packaging. BMI was first melt-blended with PF to obtain the premix with a reduced softening point for meeting the requirement of melt-kneading process. 2-Ethyl-4-methylimidazole with a dosage of 2 wt % of the ternary resins, could effectively promote the curing reaction, making the molding process of BPE molding compounds be compatible with that of the existing epoxy molding compounds (EMC). The introduction of BMI component could enhance the chain rigidity and heat resistance of cured resins. When the BMI content was more than 70 wt % of the ternary resins, the cured BPE molding compounds exhibited the glass transition temperature and initial decomposing temperature larger than 250 and 400 °C, respectively, indicating a much superior thermal performance to that of the cured EMC. Moreover, the flexural performance and the adhesion strength with copper at 260 °C, high-temperature aging resistance, dielectric properties, and thermal conductivity of the cured BPE molding compounds were also improved compared with those of the cured EMC. This study provides a promising strategy for preparing heat-resistant electronic packaging molding compounds.

Heat-resistant molding of compounds is an indispensable part in encapsulating future electronic power devices. Herein, it is used for polyfunctional epoxy resin (EP) and diamine-phenol benzoxazine (BOZ) as resin matrix, 4,4'-diaminodiphenylmethane (DDM) as curing agent, and iron acetylacetonate (Fe(acac) 3 ) as curing accelerator, as well as inorganic fillers and other auxiliaries, to prepare heat-resistant molding compounds. The curing behavior, processability and thermal performance of the EP/DDM/BOZ (EDB) resin blends containing different contents of DDM, BOZ, and Fe(acac) 3 are first systematically investigated. The EDB molding compounds (MC EDB ) with suitable BOZ content show good processability, and the molding process can be compatible with that of commercial epoxy molding compounds (EMC). With increasing the BOZ content, the glass transition temperature of cured MC EDB is greatly enhanced to a maximum of 261 °C determined by dynamic mechanical analyzer, owing to the hydrogen-bond interaction generated after polymerization of BOZ increasing the rigidity of network chains. Moreover, the cured MC EDB also exhibits higher thermal decomposition stability, better high-temperature (200 °C) mechanical properties, and lower water absorption compared to the cured EMC. After high-temperature (200 °C) aging for 500 h, the cured MC EDB with suitable BOZ content still maintains outstanding performance. This study provides a promising strategy for preparing heat-resistant electronic packaging molding compounds.

No abstract

No abstract

Latent curing accelerators are essential for application to one-component epoxy systems in various industries, such as coatings, adhesives and electronic packaging. Herein, we developed organic-inorganic hybrid microcapsules encapsulating triphenylphosphine (TPP) by Pickering emulsion polymerization of styrene and methoxyethyl methacrylate with dimethoxydiphenylsilane-modified silica nanoparticles as emulsifiers. The microcapsules were further surface-modified by epoxy silane and employed as a thermal latent curing accelerator for an epoxy/anhydride system. Good dispersibility and interfacial bonding of the hybrid microcapsules with the resin matrix were observed. Compared with TPP, the microcapsule-type accelerator endowed the one-component epoxy curing system with significantly enhanced storage stability at room temperature of 25 °C (a pot life of 20 days) and a comparable curing activity at high temperature. The activity of the encapsulated accelerator can be blocked and released rapidly and effectively with increasing temperature to trigger the segmental motion of the polymeric microcapsules. Furthermore, the addition of microcapsules increased the glass transition temperature and thermal stability of the epoxy thermosets owing to the organic-inorganic hybrid character. Moreover, the toughness of the cured resin was also improved. Therefore, the latent curing accelerator demonstrated a promising prospect for application in highperformance one-pot epoxy formulations.