Abstract: A moistureproof multilayer film, including a composite film having a non-moisture absorbing resin layer and a vapor deposited film of an inorganic oxide or a metal formed on at least one side of the non-moisture absorbing resin layer, the multilayer film having such a layer structure where the vapor deposited film surface of the composite film is laminated through an adhesive layer on a vapor deposited film surface of another composite film or a surface of another non-moisture absorbing resin layer, wherein a total number (n) of the deposited films laminated adjacent to the adhesive layer is 2 to 8, and wherein a moisture permeabihty (W; unit: g/m2.day) as measured under conditions of a temperature of 40° C. and a relative humidity of 100% satisfies a relation represented by equation W≦(1/n)×0.20, and a method for producing the moistureproof multilayer film including heat-treating the multilayer film in a hot dry atmosphere having a temperature lower than 140° C. but not lower than 55° C.

Abstract: An optical phase plate is provided in the form of a drawn and oriented film or sheet, having a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin in a mixing ratio of the former to the latter between about 65/35 and about 85/15 by weight, in which the crystal structure of the vinylidene fluoride resin consists mainly of a .beta.-form and the film or the sheet has dimensional stability and a retardation value R within a range from 500 to 650 nm. The optical phase plate is produced by uniformly kneading and melt-extruding the predetermined PVDF/PMMA mixture into a sheet and subjecting the sheet to drawing and then to heat treatment.

Abstract: Separate polarizing electrodes are attached to the opposite surfaces of a thermoplastic film. A high D. C. voltage is then applied across these electrodes to polarize the film to produce an electric element, such as an electret, piezoelectric or pyroelectric element. Portions of the polarizing electrodes are then selectively removed to form the operating electrodes required for the electric element.

Abstract: For making a piezoelectric thermoplastic film device, a polar thermoplastic film is provided on both sides thereof with conductive layers which function as polarizing electrodes during the polarizing step. In a polarizing zone, a polarizing voltage is applied across the electrodes while the film is heated to a suitable polarizing temperature. To reduce undesirable capacitive effects, at least one electrode layer is separated into sections by narrow insulating regions extending transversely across the film. After cooling, the polarizing voltage and the accumulated electric charges in the film are removed.