| 摘要 |
<p>The invention concerns a precut seal for sealing a jar, typically made of polystyrene or polypropylene, of large volume ranging from 200 ml to 1 liter, formed by cutting out a multilayer material comprising an aluminium layer Al, a layer of plastic material MP and an inner sealing layer CS. The invention is characterized in that a) the thicknesses EA1 and EMP of the aluminium layers and or plastic material MP are such that EA1/EMP range between 0,5 and 4, b) the sum of the thicknesses EA1 + EMP ranges between 30 µm and 100 µm, c) the thickness EA1 of the aluminium layer ranges between 15 µm and 45 µm, d) said plastic material MP is typically a biaxially oriented film, comprising polyethylene terephthalate, and/or polyamide, and/or polypropylene, and/or polyethylene, e) said seal comprises destacking means, typically embossing means, selected such that the tear strength of an embossed seal or of said embossed multilayer material is not less than 80 % of the tear strength of a corresponding non embossed seal or of said multilayer material non embossed. The invention provides the advantages of obtaining perfectly flat seals, capable of being destacked, economical and with non elastic folding ensuring resealing of the jar after a first opening. Said seals exhibit high tear strength.</p> |
