| 摘要 |
PROBLEM TO BE SOLVED: To increase the easily opening property of a cover material and also increase the barrier capacity and the pressure-resistant capacity and further, increase the adaptability for food, by a simple processing and low-cost means. SOLUTION: After a heat-adhesive resin layer 13 made of unstretched polypropylene film has been laminated in a dry condition on the rear face of a base material layer 12 made of a polyester film provided with a pattern- printed layer 11 at one side face, for instane, a release agent layer 14 wider than the seal part 3 is formed at a specified position of the front side of the base material layer 12 to correspond with the seal part 3, and a pattern-printed layer is formed on the release agent layer 14, and cutting lines 15, 16 of perforations piercing the base material layer 12 from the heat-adhesive resin layer 13 and stretching so as to form a ring, are formed in accordance with the external peripheral position and the internal peripheral position of the release agent layer 14, and further, a barrier layer 17 (transparent resin layer) is formed on the pattern-printing layer 11. |
