Patent ID: 7479003

Claim:
A device for producing a film made of a thermoplastic material, having at least one extruder with a blow head ( 1 ) for an emergence of a film bubble ( 4 ) from a plastic material, a calibrating device ( 20 ) acting on an exterior of the film bubble ( 4 ) and a flattening device ( 3 ) for the film bubble ( 4 ) arranged downstream of the calibrating device ( 2 ), at least one of the calibrating device ( 2 ) and the flattening device ( 3 ) having film guidance elements ( 5 ) chargeable with an airflow, wherein air outlet openings for an exit of the supplied air flow are in an area of the surface of the film guidance elements facing the film bubble ( 4 ), the device comprising: a surface of each of the film guidance elements ( 5 ) facing the film bubble ( 4 ) and formed by an air-permeable microporous layer of a mean pore size of 5 to 100 μm and a plurality of support arms ( 21 , 31 ) each carrying on a free end adjoining an outer circumference of the film bubble ( 4 ) a film guidance element ( 5 ) and each of the film guidance elements ( 5 ) being provided with an air inlet opening ( 55 ).