| 摘要 |
<p>A flexible polymeric multilayer packaging film permits an easy-opening package to be produced by heat sealing two layers of film together. The film has at least five layers, namely a heat sealable layer (712), a central gas barrier layer (716) and a moisture-resistant layer (720), plus two adhesive layers (714,718) respectively located between the heat sealable layer and the central layer, and between the latter and the olefinic layer. The package is formed with a heat seal between two confronting heat sealable layers (712), the seal having such strength that the layers (712) are effectively inseparable. If the two layers of film are subjected to oppositely-directed pulls (arrowed), ply separation occurs at an interface between layers other than the heat sealable layers (712), following a partial tearing of the film. As shown, tearing is through a heat sealable layer (712) and the associated adhesive layer (714) adjacent the heat seal and ply separation occurs between the latter layer (714) and the central layer (716) and propagates through the area of the seal to open the package.</p> |
