| 摘要 |
<p>PROBLEM TO BE SOLVED: To form an aeration passage to be opened by a pressure within a packaging bag only by a heat-sealing process without any special process. SOLUTION: A bottom film 4 is formed by material having a weaker sealing strength of each of front and rear films 2, 3 and then a V-shaped non-melted adhering segment 10 having a different slant angle is formed at the bottom seal segments 7, 8 of the bottom film 4 and each of the front and rear surface films 2, 3. The bottom film 4 is formed such that a position of a crossing point section 11A of the non-melted section 10 is displaced with each of the front surface film 2 and the rear surface film 3 so as to be raised in a slant form, and when the packaging bag 1 is bulged out, a tension force of each of the films 2, 3 and 4 is applied concentrically at the extremity end of the non-molted section 10 of the front surface film 2, resulting in that the most weak seal portion is peeled off and then an aeration passage 25 is formed.</p> |
