Effect of molecular weight of PVA on the reactivity and stability behavior of adhesive

All kinds of poly (urea-urethane) microcapsules containing hardener derivatives as a core material were prepared by an interfacial polymerization process in order to investigate the reactivity and stability behavior for application of adhesive. The results show that the prepared microcapsules were smooth and compact; in addition, average diameters were 1-20 μm. When they mix with epoxy resin as adhesive, the exothermal peaks of the curing reaction were under 110°C and reaction heat were above 400J/g; furthermore, the variation of reaction heat decreased less than 10% when the formulas stored in room temperature for 30 days. The results indicate the latent hardener shows great heat reactivity and storage stability for electronics packaging.