| 摘要 |
<p>A sealing film is produced by coextruding materials of different chemical/physical and mechanical properties, these are fed directly from the extruders to the combining tool (block box) so as to make an e.g. five-ply prod.. This prod. has an outer film of sealing material (which meets the polystyrene containers such as bowls contg. foodstuffs) adjacent a priming coat and then a layer of heat-resistant material, the dimensions of the various layers being those to suit the applications. ADVANTAGE - The prod. bonds well to seal off polystyrene but can be peeled off again to allow the package to be opened. The structure of e.g. five layers combines the desired properties, and the individual layers are selected to bond together.</p> |
