Microencapsulation of imidazole curing agent for epoxy resin

An epoxy resin–imidazole system was used to form the adhesives for the anisotropic conducting film (ACF), and a latent curing system was necessary for the ACF. In this study, 2-phenylimidazole (2PhI) was encapsulated for the latent curing system. Polycaprolactone (PCL) was used as the wall material, and the solvent evaporation method was used to form the microcapsule. The effects of the ratio of 2PhI and PCL, and the effects of the molecular weight of PCL were investigated during the microcapsule formation. The amount of 2PhI in the microcapsule was measured using TGA. The permeability of the microcapsules was measured in ethanol, and the shelf life of the microcapsules was also studied for the epoxy resin. The curing behavior was examined using DSC. In the curing reaction of the epoxy resin, the microcapsule of 2PhI exhibited a delayed kinetic behavior compared to pure 2PhI. This microcapsule of 2PhI exhibited a long shelf life, and the curing did not occur in this microcapsule–epoxy resin system at 20 °C for more than 30 days.