Stretched plastic film prodn.

摘要

A thermoplastic film tube is cut spirally, pref., for the prodn. of stretched flat film with its direction of stretch at an angle (molecular orientation). Continuously drawn film tubing has a moving part which is widened out into a cylinder and this is drawn forwards axially; a knife cuts the part spirally and the flat material formed is taken off the expanded tubing; the flat film removed is then reeled. A pair of traction rollers is mounted on a frame to act on the lay-flat tubing; a driven revolving frame has a rotating plate or similar carrying a set of rod-like or similar supports arranged concentric with the axis of rotation of the plate. The knife is fixed on to this set of supports or the frame and cuts the tubing as it runs on the rods; the axis of rotation concerned is aligned with the gap between the traction rollers, and passes approx. through its mid-point. The rotating plate or similar is connected to at least one rod and one roller to turn with it; the lay-flat tubing passes over the rod and roller towards its reeling arrangement whose axis of rotation intersects at right angles or is aligned with the axis of rotation of the plate