Abstract: A plastic film for use in a film capacitor is made by coating a backing film with a layer of polymerizable compounds which are dried but not reacted on the backing film. To this coating a metal layer is applied and the backing film with the metal layer thereon is superposed with other portions of such film and backing layers and pressed at a reaction temperature capable of cross-linking the compounds and effecting polymerization to yield a capacitor of high resistance to moisture.