Flat-film extrusion line

for PPfor PETfor stretch film

The preferred choice of raw materials for capacitor films are polypropylene (PP) and polyethylene terephthalate (PET). PP is independent of frequency and temperature (<105°C) and has a high impulse stability – therefore it can be used in AC and DC applications. Compared to this, PET is heavily dependent on frequency due to its high loss factor and so it is mainly used in DC applications. Both types of capacitor film are produced by biaxial stretching where a more perfect crystalline structure is formed and the dielectric strength can be increased. Since 1970, when the first capacitor line was supplied by Brückner, more than 40 lines have been successfully installed. Sequential stretching process for highest film quality: Optimised surface roughness, good self-healing effect Simultaneous stretching process: Growing demand for quite special and high-value applications - Low MD shrinkage even at low thickness - Higher potential for thinnest film due to high stretching ratios Production speeds up to 350 m/min and an output up to 1,100 kg/h Lowest film thicknesses below 1 µm Extremely thin films and high-temperature films for future-oriented EV applications High energy density film for renewable energy applications in the power industry Close cooperation with raw material suppliers High break down voltage Material optimisation for the sequential as well as the simultaneous stretching process Film Type Thickness Range Capacitor film for metallising 2 - 12 µm Capacitor film for impregnation 10 - 12 µm