| 摘要 |
PURPOSE: To provide a manufacturing method of polyvinyl chloride-based heat- shrinkable film, which has small natural shrinkage due to change with the lapse of time and favorable packability. CONSTITUTION: Polyvinyl chloride sheet 25 is heat-treated in a stretching zone 50 so as to obtain stretched film having the unidirectional stretching of 200-400%. After the stretched film has passed through the stretching zone 50, the stretched film is heat-treated and contracted at a contracting zone 80. The length in stretching direction of the film just after the finish of the contracting zone 80 becomes shorter by 2-10% than that just after the finish of the stretching zone 50. After the finish of the contracting zone 80, the stretched film is cooled down at a cooling zone 7 so as to obtain the polyvinyl chloride- based heat-shrinkable film. |
