Receptacles – Receptacle side wall made of two or more layers of material... – Beverage receptacle
Patent
1996-08-26
2000-08-08
Thibodeau, Paul
Receptacles
Receptacle side wall made of two or more layers of material...
Beverage receptacle
220 6222, 220669, 72338, 72349, 723794, 72715, B65D 2500, B65D 608, B21D 2800
Patent
active
060988290
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention falls in the technical area of the fabrication of components, can bodies and ends, easy-open or not, intended for the packaging of food products by drawing, in one or several passes, starting from a layered metal-plastic construction.
More precisely, the metal-plastic construction used in the present invention is of the type metal-polymer-metal, that is in which a layer of polymer is interposed between two metal sheets to which it is adhered.
In the text of this patent application, we will use without distinction for this concentration the terms metal-plastic-metal, metal-polymer-metal, or more simply in an abbreviated fashion, MPM.
There are numerous documents describing layered metal-plastic constructions. The majority of these concern metal-polymer or poly-metal-polymer constructions, metal-polymer-metal constructions being rarer.
Of those documents which do mention MPM constructions, there is none that teaches what range of materials and thicknesses are suitable for making drawn and ironed beverage or food cans.
By way of illustration one can cite the international PCT application filed on Jun. 25, 1981 by Metal Box Limited and published under the number WO 82/00020 on Jan. 7, 1982. This application has given birth in particular to the European patent EP 055 719.
This patent describes a metal-plastic construction in the simplest form of realization of a polyethylene (called for abbreviation PE) film attached to a foil or plate of metal. Another method of realization consists of two films of PE attached to opposite surfaces of a metal plate to form a complex PE-metal-PE. Finally, a third method of realization consists of two plates or foils of metals attached to opposite surfaces of a PE film. The PE used, obtained by copolymerization under a low pressure of ethylene and of butene-1, is of the type linear low density at a density of between 0.91 and 0.94 and it has been found that this particular type, whose characteristics are described in the application, has the interesting property of adhering directly to the metal without needing to use an adhesive. It suffices to adhere it to the metal by the simultaneous application of heat and pressure (heat sealing).
The metallic substrate can be steel, steel having a coating of tin or of chrome or of chrome/oxide or of zinc, of aluminum treated or not with nickel, copper, or zinc. It can have undergone a chemical conversion treatment.
Although there is no explicit teaching as to the desired absolute or relative examples of simple metal-plastic constructions in which the films of different types of polyethylene of 100 microns thickness are thus heat sealed on the plates of different metals; steel, tin plated steel, steel coated with chrome-chrome oxide, or aluminum of a thickness of 210 microns. The specimens obtained are then formed into hollow articles by folding, stamping, drawing, wall-ironing. The adhesion of the coatings is compared and demonstrates the superiority of linear low density polyethylene.
The French patent FR2 665 887 (Pechiney Emballage Alimemntaire) describes a capsule to fit over a cork made by drawing, drawing and ironing, or flow turning, characterized in that it is comprised of two layers of aluminum bound together by an adhesive layer of shore hardness less than 80. The adhesive layer can be constituted of an ethylene acrylic acid or of polyethylene, or of polypropylene modified with acid functionaltiy. The total thickness of the complex is comprised between 120 and 400 microns with the following percentage distribution of the total thickness:
______________________________________ Outer layer of aluminum
20 to 50%
Adhesive layer 3 to 30%
Inner layer of aluminum
40 to 60%
______________________________________
European Patent Application EP-A-0 046 444 assigned to Schwerzerische Aluminum AG describes an MPM composite foil in which the plastic layer could be as thick as the two metal layers combined. One stated requirement for achieving deep drawability is to select the plast
REFERENCES:
patent: 3721597 (1973-03-01), Colburn
patent: 4313996 (1982-02-01), Newman et al.
patent: 4403010 (1983-09-01), Festag et al.
patent: 4594292 (1986-06-01), Nagai et al.
patent: 4671985 (1987-06-01), Rodrigues et al.
McHenry Robert J.
Petit Dominique
Rickman Holly C.
Thibodeau Paul
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