Abstract:
Disclosed is a container, made by folding, with fold-in flaps, for packaging food. The container can be recycled economically, i.e. with a profit. The material consists of a metal sheet coated with a plastics skin which, when the metal is recovered, produces no residual matter or pollutants. The edges of the containers are welded to each other by the plastics coating. After bending open the flaps, the container can be easily laid flat by hand (thus reducing its volume) without it springing back and used containers can be collected in compact form in a recycling container and transported in the recycling container to the recycling facility where the metal is recovered by melting.

Description:
DESCRIPTION 
     The invention relates to a receptacle consisting of a monoplane material and to a recycling process for the receptacle. “Recycling” is taken to mean the recovery of raw materials. 
     Such receptacles are customarily made of paper which has been suitably treated in order not to allow liquid or semi-liquid foodstuffs to seep through the packaging material or to have a detrimental effect on it. The margins of the original sheet of paper are glued together after the shaping process and folded in for reinforcing purposes so that, for instance, a quadrate receptacle is formed, as is familiar from milk packs. The paper material is difficult to recover in the case of these receptacles because it is interspersed with ancillary materials such as aluminium due to the special treatment of the paper. Such receptacles affect the environment because they cannot be destroyed except by incineration, whereby pollutants may be released, however. Other receptacles are made of a tinned metal sheet which is welded, for example, with its margins, as is known from tins, so that the contents are closed off under air-tight conditions. The tinning serves to prevent the sheet from rusting and/or as a lubricant in the deep drawing and/or ironing process. It is difficult to detach when recovering raw materials, so that recovery of the raw materials is uneconomic. Moreover, the use represents a waste of raw material because tin is an increasingly scarce commodity worldwide. Above all, however, the bulky geometric form of the known tins is difficult to destroy mechanically (not manually). This is due to tins not being folded from one piece of material but being produced by other methods. Other receptacles in the form of bottles or the like are in fact suitable for a recycling process. They involve, however, cost-intensive return transport and special cleaning measures, which for their part pollute the environment. Moreover, bottles are highly susceptible to mechanical damage, so that the reject rate is relatively high. Another recovery method is to transport the empty bottles back to a glassworks in order to melt down the glass. The return transport is cost-intensive because bottles are a bulky commodity. 
     It is the object of the invention to provide an intrinsically stable packaging receptacle, in particular for foodstuffs, which consists primarily of a reusable metal, from which the raw material can be recovered with minimum pollution and with economic efficiency after its designated use following a reduction in volume which can be carried out effortlessly and easily by hand as well as a recycling process for such a receptacle. 
     This object is solved by the characterizing feature of claim  1 . 
     The metal sheet has a thickness in μ-range, depending on purpose. The applied plastic skin prevents the sheet from rusting. It furthermore serves to weld the seams of the receptacle. The starting material can be folded into receptacles in the same way as paper receptacles. 
     In contrast to conventional tins made of metal sheet, the receptacle according to the invention has the advantage that, when it is empty, it can be easily compressed flat manually, if just the flaps of the receptacle are folded upwards, whereby it retains its compressed flat form with no special measures, i.e. does not tend to spring apart again. In this form it can be collected in a container, namely collected in compact form, so that it is worthwhile transporting the container to the reprocessing location. To prevent extraneous material from being deposited in the container, the latter can be provided with a flat slot capable of receiving only the used compressed material. In contrast to paper receptacles with an aluminium and/or plastic additive, the receptacle according to the invention is easy to recycle. In order to implement the recycling process, the compressed receptacles are heated until the metal melts and the plastic burns under heat discharge. The plastic is burned without any environmentally incompatible pollutants being released, apart from CO 2 . The energy being released in the form of heat can be used subsequently and replaces the primary energy which is necessary in any steel works, as a result of which the proportion of CO 2  being released is ultimately not increased. 
     If such a receptacle is thrown inadvertently into the normal domestic refuse, the packaging material can be recovered at the refuse collection point, namely by means of a magnet, if or because the metal as such is ferromagnetic. 
     The metal sheet as such is completely enclosed by the applied plastic skin. The metal sheet cannot rust, at least not until the plastic detaches itself from the metal. This is the case only after a considerable time. The metal sheet cannot have a detrimental effect on the foodstuffs either in taste or in durability, because the plastic skin forms an insulating layer. Moreover, light penetration is prevented if the receptacle wall is given sufficient thickness by its layered materials. The metal can moreover be printed prior to shaping, for example in the manner of newspaper printing. The print is then under the plastic skin, which in this case is transparent. The printing is therefore resistant to scratching and wiping. Instead of the metal sheet, the plastic skin can also be printed. 
     In order to be able to empty out the contents, one of the flaps can, as actually known, be folded upwards to be cut off, as a result of which the receptacle contents are accessible. In a further development of the invention, a perforation is provided along which at least one of the flaps can be torn off. However, an opening which can be pierced by a straw, for instance, can also be provided, as actually known, which is formed according to the invention by material thinning, for instance of the metal sheet. The provided piercing point is located advantageously protected under a flap which is bent back for emptying purposes. An opening which is closed with detachable adhesive tape can, however, be provided from the outset in the receptacle wall. 
     Further details of the invention can be gathered from the sub-claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention is shown on the drawing, wherein 
     FIG. 1 shows the top view of a length of packaging material; 
     FIG. 2 shows a section along the line II—II of FIG. 1; 
     FIG. 3 shows the side view of a semi-shaped receptacle; 
     FIG. 4 shows a view of the receptacle shown in FIG. 3 towards the arrow IV in finished form; 
     FIG. 5 shows the top view of the receptacle shown in FIG. 4 towards the arrow V; 
     FIG. 6 shows a receptacle in compressed state after being emptied. 
    
    
     According to FIG. 1, the packaging material ( 1 ) is rectangular in form and is laid out in one length. It consists according to FIGS. 1 and 2 of a pure metal sheet ( 2 ) to which a plastic coating ( 3 ) is applied on all sides. The plastic coating ( 3 ) projects with a margin ( 4 ) over the margins of the metal sheet ( 2 ). The metal is thus protected from rusting. 
     To shape the receptacle, the packaging material is folded along the lines ( 5 ), so that a receptacle ( 6 ) as shown in FIG. 3 is produced in an initial stage. The top and bottom strip ( 7 ) of the packaging material forms in part the top and bottom closure of the receptacle ( 6 ), and the surplus material is shaped into flaps ( 8 ). 
     According to FIG. 4, the flaps ( 8 ) are folded in. They can be welded to the actual receptacle ( 6 ) by means of the plastic skin. The flaps stay close to the receptacle without any special attachment, however, even after being folded upwards, on account of the characteristic of the material. 
     The overlapping inside and outside surfaces of the edges ( 4   a  and  4   b ) are also welded to one another. The top and bottom margin ( 9 ) of the packaging material also overlap after the folding operation and are welded by means of the plastic skin. 
     The receptacle formed in this way is extremely stable due to its production by folding, whereby a stable geometric triangle is formed. The stability is moreover increased by the welded margins ( 9 ) and by the flaps ( 8 ) being bent in and positioned against the receptacle and possibly welded to it. The stability is moreover supported by the foodstuff once it has been filled in. When the receptacle is empty it can, as shown in FIG. 6, be compressed without difficulty into shape ( 10 ). The welded flaps are detached if necessary from the receptacle for this purpose and then folded back. This destroys the stable geometric triangle contained in the packaging body. On account of the bending characteristics of the metal sheet ( 2 ), the receptacle retains its compressed form without springing back. 
     The former flaps are marked again with ( 8 ) for this purpose. 
     In the compressed form the receptacle can be pushed through the slot of a container or the like, so that it is stored in a compact filling quantity which can be used for the recycling process to the effect that the metal sheet melts on being heated and can be recovered without any special further measures as it is pure, i.e. it has no inclusions. The plastic is burned at this temperature without any residue. The combustion heat can be collected and used. All that escapes in this recycling process is CO 2  through the burning of the plastic. 
     Reference numbers 
       1  Packaging material 
       2  Metal sheet 
       3  Plastic coating 
       4  Margin of plastic skin 
       4   a  Edge 
       4   b  Edge 
       5  Folding lines 
       6  Receptacle 
       7  Strips 
       8  Flaps 
       9  Margins 
       10  Compressed form