| 摘要 |
<p>A bag of synthetic material, particularly of polyethylene, is formed by folding two parts of the walls over one another and adhesively bonding them, a bottom flap also being optionally applied, the bag being formed from a tube with two layers not entirely joined to each other, one being of a fibrous material permeable to gas which constitutes the inner wall of the bag. The inner layer is preferably of paper with a high extensibility and a gas permeability of at least 1000 cm3. m-2.mn-1. The two layers are preferably sealed together by an adhesive applied at points or in bands. The bags, while possessing an impermeable outer surface, have an inner layer permeable to air and which allows it to escape during filling.</p> |
