BLOWN FILM INSTALLATION, METHOD FOR PRODUCING A BLOWN FILM STRIP AND FILM PRODUCED THEREWITH

摘要

In blown film installations, it is known to provide longitudinal stretching of the produced double layer film strip downstream of the draw-off, more precisely downstream of the reversing unit and upstream of the winder. It is also known to stretch the down-drawn film, wherein the film must then be preheated owing to the long cooling path from the draw-off. According to a first feature, the present invention specifies warming the film above the draw-off and then treating it mechanically. The film can thereby be brought with only little energy from a first level of warmth to a temperature level at which it can easily be worked. According to a second feature, the invention specifies providing a tractive force breakdown brake.

主权项

1. A blown film installation (1) with an annular nozzle for extruding a film tube, with a tube formation area for longitudinal and transverse stretching of the film tube, with a cooling means for the film tube moving in the machine direction, with a collapsing section of the film tube into a double layer film strip and with a pair of haul-off rollers beyond the cooling means for hauling off the film tube, wherein a processing roller line (8) for longitudinal stretching of the double layer film strip is disposed beyond the pair of haul-off rollers (2) in the machine direction,
wherein the machine direction is oriented vertically from the bottom up and the processing roller line (8) is disposed above the pair of haul-off rollers, wherein a heating means is provided for the double layer film strip (23).