Ferroelectret double and multilayer composite and method for production thereof

The method comprises structuring a first surface of a first polymer film (1) by stamping under formation of a height profile, applying a second polymer film (5) to the structured surface on the first polymer film, joining the polymer films to give a polymer film composite with the formation of cavities and electrically charging inner surfaces of cavities (4) with opposing electrical charges. The stamping is carried out under use of a structured roller or a structured embossing die. The structuring is carried out by shaping polymer film. The method comprises structuring a first surface of a first polymer film (1) by stamping under formation of a height profile, applying a second polymer film (5) to the structured surface on the first polymer film, joining the polymer films to give a polymer film composite with the formation of cavities and electrically charging inner surfaces of cavities (4) with opposing electrical charges. The stamping is carried out under use of a structured roller or a structured embossing die. The structuring is carried out by shaping polymer film by applying pressure in a form tool with pre-tempered contour insert or by a slit extrusion of polymer film with shaped nozzle. The polymer film is joined with the polymer film composite by lamination, gluing, clamping, screwing, riveting or welding such as laser welding, ultrasonic welding or vibration welding. Electrodes are subjected on the external surface of the polymer film composite before and/or after charging of inner surfaces of the cavities. The process is carried out as continuous roll-to-roll process. The edges of the polymer film composite are sealed and gas is filled in the cavity of the polymer film composite before or after charging of the inner surfaces of the cavities. Independent claims are included for: (1) a ferroelectret double or multilayer composite; and (2) a device for producing ferroelectret double or multilayer composites with cavities.