| 摘要 |
<p>The bag has an outer wall, which is closed from a flat material into a tubular shape by a longitudinal seam, where the outer wall comprises a plastic wall (1) and a paper wall (8), and a bottom is folded at one end of the outer wall. The plastic wall is partially double-layered with two adjacent layers. The two layers have mutually displaced venting perforations and are fixed to each other such that the layers are lifted from each other in the area of perforations due to overpressure.</p> |
