Cast film extrusion lines are commonly used to extrude plastic films especially for flexible packaging industry. / In a cast film extruder PE, PP or PA granulates (or other polymers) are melted inro an extruder and pushed through a flat extrusion die (T die), extruding a sheet of molten polymer onto a cooled roller (chill roll). Cast film extrusion lines designed for stretch film extrude mainly linear low density polyethylene (LLDPE) in blends with other polymers and additives. CPP coextrusion lines extrude polypropylene (PP) in various blends and multilayer structures. Barrier film structures are usually 5,7 and 9 layers and involve also EVOH and nylon (PA), which adds barrier properties to film.