Process for producing a film tube (bubble)

摘要

Film bags are overdimensioned if their wall thickness is dimensioned according to the stressing in the edge regions. There is a considerable material saving if only the peripheral regions of the intended folding edges of the film tubes intended for the fabrication of the film bags have the increased wall thickness. A process is proposed to produce such a film tube for the fabrication of film bags. According to this process, the reinforcing of a certain peripheral region of the film tube is accomplished by there taking place, in addition to the usual uniform peripheral cooling by cooling air at a cooling ring, a specific additional cooling of the extruded film tube, restricted to a narrow peripheral region, before the solidifying of the said tube.