Polyester resins evolved out of alkyd resins and became available starting in 1942. The first wartime uses were for military needs, including boats and pontoons, where they were combined with glass fibers to make strong laminates. During the decades following the end of the war, extensive development of this resin family took place and now most of their uses are nonelectrical. Their advent was, however, very important in the development of modern coil insulations.