| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a packaging bag and a method for its manufacture, wherein packaging bag being heated by a microwave oven, etc., when the inside pressure in the bag has reached a prescribed point is capable of automatically and surely releasing the pressure inside the bag from a specific point of the bag and moreover the packaging bag has an automatic pressure-governing function which is advantageous from the viewpoint of manufacturing process as well. SOLUTION: A first film 1 has a layer structure comprising a base film 1a/a layer of sealant 1b. A second film 2 has in a film 2' a layer structure of base film 2a/layer of sealant 2b and is provided with small openings (o, o) formed through in the direction of thickness by punching or by incision and with another layer of sealant 2c over the layer of sealant 2b of the film 2'. A bag is made by placing the first film 1 and the second film 2 in such a manner that the layer of sealant 1b of the former is arranged opposite to the layer of sealant 2c of the latter and by heat-sealing them.</p> |
