| 摘要 |
PROBLEM TO BE SOLVED: To avoid the phenomenon of a warpage of a flange part by a method wherein the surface layer and the intermediate layer of a lid body comprising the surface layer, the intermediate layer and a seal layer are made of a biaxially drawn polyester, and at the same time, at least on either one of the layers, an oxygen gas barrier treatment is applied. SOLUTION: A polyester which constitutes the surface layer and the intermediate layer of a lid body is made of a biaxially drawn polyester resin, and on at least either one of the layers, an oxygen gas barrier treatment is applied. For a substance imparting such a function, in addition to a film on which a polyvinylidene chloride resin is coated, a substance on which an inorganic substance is deposited or coated by a thickness of, e.g. 10μm or lower is used. By this constitution, when a warpage to the main body side of the packaging body at a flange part where the main body and the lid body are sealed, is made +, the value of the warpage becomes within±5 mm, and an appearance which is approx. flat and has an excellent look is presented.
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