Abstract
Shelf life stability and curability were evaluated for moisture curable epoxy resins using ketimines as a moisture latent hardener, derived from different kinds of ketones as their protective groups. Both the sheli life stability and curability of their epoxy resin compositions were influenced by the steric hindrance of ketimines. MIPK (methyl i-propyl ketone) and MTBK (methyl t-butyl ketone) having a specific structure with a narrow space <4.2Å around ketimine” N” and a wide space >3.7Å around ketimine” C” were demonstrated as the optimum starting ketones to ketimines. The lap shear strength as adhesive properties of the resins were higher using large volume ketones than those from small ones as the protective groups. These results may indicate that larger volume ketones formed by hydrolysis in their system would slow down the space in the curing of epoxy resins to a rate-determining level, and give less internal stresses on the adhesive surface. And their higher adhesive properties, obtained as another effect, were considered to be caused by a higher conversion in the reaction of epoxide using large volume ketones.
