| 摘要 |
1301198 Embossing MOBIL OIL CORP 19 March 1970 [20 Mareh 1969] 13336/70 Heading B6J A web of flexible plastics material (e.g. polyethylene) of one or more plastics films each less than 0À025 mm. thickness is emboseed between a pair of embossing rollers having on their respective surfaces positive and negative embossing patterns and whose circumferential speed is controlled to avoid strain on the web. In an embodiment, Fig. 6, a web of connected bags is produced by embossing a tubular web between rollers 25 and 26 whose speed is controlled by a unit 27. The control unit is also connected to tensioning roller 24 and pull-off roller 28 such that the speed of the web as it is applied to and withdrawn from the embossing rollers may be regulated. The web is preferably fed to and pulled from the embossing rollers at a speed higher than the circumferential speed of these rollers. The embossed web may be filled with air between roller sets 30 and 31 in order to separate the layers and then provided with transverse heat seals and tear lines at station 32 to complete the web of bags. In a further embodiment (Fig. 7, not shown) a single layer web is embossed and subsequently folded longitudinally to provide the tubular structure for forming into bags. In this case each half of the web is provided with a different pattern using an embossing roller bearing separate pattern areas 50, 52. The embossments may be in the form of truncated pyramids. |
