| 摘要 |
<p>The invention relates to the field of packaging materials, and in particular, to multi-layered materials intended for food packaging. The packaging material consists in successive layers glued together by an adhesive, said layers comprising, in one variation of the invention, a polypropylene film, a foil of aluminium and paper. In a second variation, the layers comprise a metallized polypropylene film and paper. It is preferable to follow these parameters concerning the density of the layers: in the first variation, 5 to 50 g/m2 for the polypropylene film, 15 to 300 g/m2 for the aluminium foil, 20 to 350 g/m2 for the paper and 1 to 15 g/m2 for the adhesive; in the second variation, 5 to 50 g/m2 for the metallized polypropylene film, 20 to 350 g/m2 for the paper, and 1 to 15 g/m2 for the adhesive. The co-relations between the densities of the layers allow for the production of a packaging material with optimum mechanical resistance, as well as excellent protective qualities (moisture-proof and gas-tight). The material also possesses industrial qualities, such as the fact that its firmly glued layers facilitate the packaging of foodstuffs. Paraffin, wax, or synthetic glue can be used as the adhesive.</p> |
