Film manufacture

includes melting the granulate in an extruder and pressing it to an appropriate form (extrusion). Afterwards, the plastic film is cooled on rolls whereby sterile-filtered air is used for cooling. Thus, the produced film is already protected from contamination during its production, as foreign substances can be locked in the still soft plastic material. If several film layers should be combined to create a multilayer, a coextrusion (rare) or a lamination can be performed.