| 摘要 |
<p>Production of laminated plastic film, by extruding in known manner, two thermoplastic tubes from two concentric annular nozzles, blow-moulding these independently and subsequently stretching and further blowing to bring the tubes together, with the improvement that the superimposed tubes are flattened at the drawing temperature and thereafter drawn further longitudinally and bonded to form a single but laminated film.</p> |
