Cross-Linking of a Diglycidyl Ether of Bisphenol-a with Phthalic Anhydride by Pre-Activation of the Resin with 1,1 Dimethyl Urea

摘要

Urea and its compounds heated with epoxy resins produce a reactive and toxic composition that can open the ring of the phthalic anhydrides and thereby facilitate union of the carboxyl with the epide and subsequent hydroxyl groups. Di-substituents of low molecular weight on the same nitrogen atom of urea have the highest reactivity. The quantity of activator required to cross-link the anhydride with the epide resins is of the order of parts per million. Optimum conditions of time and temperature and a range of concentrations of the urea compound can be selected to produce an activated epoxy resin. Optimum ratios of phthalic anhydride to activated resin are also available for selection in making the thermosetting plastic. (Author)