| 摘要 |
<p>The film walls at the mouth of a thermoplastic film package are doubled back at least twice, and the six or more superimposed layers are heat-sealed together. Opt. the neck 'A' of the package may be spot welded to hold it while the redoubled folds are formed and sealed. The welded ends are sufficiently large and strong to be easily gripped to tear open the relatively weak neck of the pack without requiring supplementary scissors, pull threads or perforations, etc.</p> |
