This specification covers one type of glass cloth impregnated with a heat-reactive, thermosetting, hot-melt, addition-type polyimide resin system, furnished in continuous rolls of full width material.This cloth has been used typically for structural laminates requiring high strength and heat resistance for long-term service up to 230 degrees C (446 degrees F) and short-time service up to 260 degrees C (500 degrees F), but usage is not limited to such applications.