Method and apparatus for collapsing an extruded tubular film

摘要

A method and apparatus is disclosed for lacing an extruded tube 14 of a non-derivatized cellulose through an S-wrap unit 28 to collapse the tube to a flat width. The lacing to form an S-wrap is accomplished without slowing the extrusion speed. At the start of the extrusion operation, the extrusion path leads between a pair of horizontally-oriented lacing members 30 and 32. After the leading edge 52 of the extruded tube has passed downwardly through the space 50 between the lacing members, the members are rotated as a unit to bring them into contact with opposite sides of the extruded tube. This collapses the tube and creates the S-wrap.