Method for producing polypropylene films

A process for the production of a biaxially oriented polypropylene film wherein the film comprises at least one layer, which comprises heating and melting propylene polymer B in a first extruder and shaping and extruding the molten mass of the propylene polymer B through a flat sheet die and taking off the melt exiting the flat sheet die on one or more rolls and solidifing to give a prefilm and stretching the prefilm in the longitudinal and transverse direction, wherein

• A. a propylene polymer A without a fraction of recycled material is heated and melted in a second extruder, and
• B. the molten mass of the propylene polymer A is fed to the two sides of the propylene polymer molten mass B in such a way that all of the molten masses are extruded together and simultaneously through the flat sheet die, and the propylene polymer A without a fraction of recycled material forms the border region of the film during the production process, and
• C. the two border regions comprising the propylene polymer A are cut off after longitudinal and transverse stretching of the film, and
• D. this film cut off from the two border areas is melted and mixed together with the polypropylene polymer B and extruded to form the precursor film in the first extruder.