Extended Shelf Life for PMR Polyimide Resins and Prepregs

An improved class of formulations for PMR polyimide resins retards the imidization that undesirably occurs during handling and storage. While imidization is desired at the final (deliberate polymerization) stage of production of a polyimide, imidization results in premature aging when it occurs during earlier stages of synthesis, shipping, prepregging, and fabrication layup. By retarding imidization at storage and handling temperatures, the improved class of formulations increases both shelf life and the upper limit of allowable temperature for handling and storage prior to final polymerization.