| 摘要 |
<p>A length of gusseted tube of a film of a thermoplastic material is sealed at one end with two or three parallel sealing lines (22, 24) that are connected by transverse bracing seals (26) extending at intervals across them. The bracing seals are preferably arranged at uniform intervals and may extend at right angles to the parallel sealing lines or with alternately opposed inclinations. The film may comprise a single layer or two co-extruded layers, and preferably one of the layers is made of polyethylene.</p> |
