Preparation of soft packaging material having an easy tear part

摘要

PROBLEM TO BE SOLVED: To accurately and quickly perform the forming of an easily tearable part by a method wherein a flexible packaging stock material at least the surface of which comprises a thermoplastic resin, is intermittently fed, and when the stock material is stopped, an easily tearable process to an unsealing planned area is performed by a vertical sealing, a lateral sealing and the scanning of a laser beam which synchronizes with the vertical and lateral sealings. SOLUTION: A film (flexible packaging material) which is intermittently fed out from a stock material roll 21, is sealed by a vertical heater 28 first, and after cooled by a vertical cooling plate 29, is sealed by a lateral heater 32, and cooled by a lateral cooling plate 33. Thus, the film is formed into a bag-shape. At this time, when the feeding of the film is stopped, a laser beam 1 from a laser device 40 is made to enter a tubular interference optical system 43 through a condensing lens 44 by changing the direction by a fixed beam bender 41 and a movable beam bender 42, and thus, an interference pattern is output. By this method, an easily tearable process by a linear collective interference pattern is applied on an unsealing planned area by the resin layer of the film. Then, the film is cut off by a cutter 36, and stacked.