Abstract:
A method for producing metal packages is disclosed, comprising the steps of forming a metal package, in particular from steel or aluminum, from a sheet metal material, in particular from thin or very thin sheet or tin plate, wherein the metal package comprises a cavity having inner surfaces that are coated with a paraffin-based coating material. The coating material is preferably heated after coating to a temperature above the solidifying temperature.

Description:
CROSSREFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of international patent application PCT/EP2010/061732, filed on Aug. 12, 2010 designating the U.S., which international patent application has been published in German language and claims priority from German patent application 10 2009 038 129.2, filed on Aug. 12, 2009. The entire contents of these applications are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to a method for producing metal packages from metal sheets with a coating and to metal packages of sheet material, in particular of thin or very thin sheet or tin plate, for receiving in an interior space a product with which they are filled. 
         [0003]    Such metal packages are known in principle in the prior art and are sold by the applicant in various forms including those of flat-top drums, canisters, seamed-lid cans, hobbocks and barrels. 
         [0004]    Such metal packages are used for packaging and storing chemical/technical products, foodstuffs and, in particular, beverages. They are produced by means of methods that are generally known in the prior art, including separating and reforming processes. Connections are thereby created by various operations including that of seaming, with previously flanged edge regions of metal sheets being connected to one another by folding them over. 
         [0005]    The known metal packages make it possible for the aforementioned products with which they are filled to be received in a mechanically stable container in such a way that they are protected from light and sealed. The sealing extends here to liquid, gaseous and gas-tight constituents of the products, and similarly undesired permeation through the packaging material is avoided. In addition, such containers are suitable for receiving pressurized products. Metal packages are almost completely recyclable, it being possible to obtain a virtually closed material cycle for the packaging materials if they are consistently recovered and reused. 
         [0006]    To ensure that the containers are resistant to corrosion, acid and general media, it is necessary to provide their surfaces, in particular also the inner sides, with a protective coating. This coating may be, for example, a combination of a metallic layer, for example a tin coating in the case of tin sheet, and an organic coating applied on top, such as for example a lacquering or an applied film. Such coatings are generally applied before the reforming operation to the semifinished product, flat material, plate material or metal strip. 
         [0007]    It has been found that the operations for reforming the starting material that follow in the course of the production of the metal package, such as for example drawing, flanging or seaming operations, can impair the protective effect of a lacquer layer particularly. For this reason there has been a change in the practice employed, to alternatively or additionally coating the interior space of a completed or semifinished metal package with lacquers by an internal spraying method. However, it must be noted here that the internal spraying method does not allow the lacquer layer to be applied to all the component parts of the package, such as for example in the case of interior spaces in a package with areas that are difficult to access or with very small filling openings. 
         [0008]    In the course of the subsequent application of lacquers, it is necessary for the coating to be followed by a drying operation. This involves the lacquer layer being dried or baked at a greatly increased temperature, for instance at 180 to 200° C., which is applied for a considerable time period, for example approximately 12 minutes. This high thermal loading necessarily requires more complex equipment and greater expenditure on the supply of energy and the disposal of emissions, such as for example of degasifying and evaporating matter. Furthermore, such treatment may cause the risk of a coating, printing or lacquering of the outer side of the package being damaged. 
       SUMMARY OF THE INVENTION 
       [0009]    In view of this, it is a first object of the invention to disclose a method of producing metal packages allowing for improved corrosion protection. 
         [0010]    It is a second object of the invention to disclose a method of producing metal packages that renders possible a relatively simple production. 
         [0011]    It is a third object of the invention to disclose a metal package that has increased corrosion protection. 
         [0012]    According to one aspect these or other objects are solved by a method comprising the steps of:
       providing a metal package made of sheet metal and having a cavity formed by inner surfaces;       
 
         [0014]    providing a paraffin-based coating material; 
         [0015]    heating said coating material to a temperature above a solidifying temperature thereof; 
         [0016]    applying said coating material onto said inner surfaces of said cavity; 
         [0017]    solidifying said coating material; and 
         [0018]    cooling said metal package to room temperature. 
         [0019]    With respect to a material package of the type mentioned at the outset, the object of the invention is achieved in that at least the interior space of the package has a surface coating comprising a paraffin-based coating agent. 
         [0020]    The object of the invention is completely achieved in this way. 
         [0021]    This is so because, according to the invention, a metal package is formed and then its interior space is coated with a paraffin-based coating agent, so as to obtain an organic coating which ensures excellent corrosion protection and is not subjected to any subsequent mechanical deformation or damage caused by reforming processes in the production of the metal package. In this way, a high integrity of the coating can be ensured. 
         [0022]    One particular advantage of the solution according to the invention is that a greatly reduced porosity is achieved in comparison with spray lacquered coatings. Consequently, corrosion currents can in principle be minimized or prevented, which leads to much improved corrosion protection. Accordingly, it may also be possible for a package according to the invention to be successfully filled with aggressive products, which for instance contain acids or lyes. 
         [0023]    Paraffinic hydrocarbons are non-toxic and are not considered to be a health hazard, and so they can certainly come into consideration for use in packages for foodstuffs or beverages. In addition, on account of their non-reactivity, paraffins are outstandingly suitable as corrosion protection agents; they are, in particular, not water-soluble and are very resistant to many kinds of acids. Consequently, they are particularly suitable for use in metal packages for carbonated beverages, such as for example beer or cola. 
         [0024]    For the purposes of this application, the paraffin-based coating agent should be understood as meaning a substantially paraffin-containing coating agent which advantageously consists of paraffin to over 75%, preferably to over 85% and more preferably to over 95%. The coating agent may be supplemented by adding fillers, solvents, dyes, binders and other additional substances, for example fats and natural or synthetic waxes, or else by additions of production-related residual constituents, such as for example oil residues. 
         [0025]    It is conceivable for the coating agent to consist completely or almost completely of paraffin. In this way it can be ensured that no, or only insignificant, constituents of the coating agent are released after coating by degassing or dissolving. 
         [0026]    It should be noted in this connection that paraffins should be understood as meaning substantially paraffinic hydrocarbons, which generally have a low reaction tendency. Paraffins may be composed of unbranched (n-) and branched (iso-) alkanes, the reason for their advantageous properties. Paraffinic hydrocarbons are substantially wax-like, odorless and tasteless, electrically nonconducting and hydrophobic. 
         [0027]    Depending on their chain structure, paraffins may be classified according to their viscosity and their solidifying temperature. This application is primarily, but not exclusively, intended to focus on mixtures with particularly long-chain hydrocarbons. Furthermore, paraffins should also be understood as including what are known as micro waxes. 
         [0028]    According to a development of the invention, the coating agent is applied under pressure, in particular by the airless spraying method. 
         [0029]    In this way it is made possible to apply the coating agent by means of known techniques. A uniform initial coating is obtained. The airless spraying method is particularly suitable for applying the coating agent, since, by contrast with air-pressure-based spraying methods, the coating agent is applied here without an additional carrier medium. This allows contamination of the metal package or the coating agent with constituents of the process air that occur in a method with compressed air to be avoided. Similarly, there is no need for laborious preparation, cleaning or filtering of the process air. In an alternative refinement of the invention, the coating agent is applied by means of a pouring or sprinkling method. 
         [0030]    This measure allows the coating agent to be applied without pressure. Consequently, the complexity of the production and equipment is reduced. It is also possible here to dispense with the use of process air for applying the coating agent, so that contamination of the metal package and of the coating agent can be reduced, thereby increasing the quality of production and the reliability of the process. 
         [0031]    Applying the coating agent by gravitational force by means of pouring or sprinkling methods can similarly ensure influencing of the layer thickness to be achieved. By variation of various parameters, such as for example the viscosity of the coating agent, the temperature of the coating agent or of the metal package to be coated or else the surface finish of the interior space of the metal package, a desired layer thickness can be set. 
         [0032]    In an advantageous development of the invention, for coating, the coating agent is heated to a temperature above the solidifying temperature. 
         [0033]    This measure makes it possible to process paraffin-based coating agents without the addition of solvents. In this way, only local areas of the production plant have to be heated, thus promoting rapid adhering and solidifying of the coating agent on the metal package not heated by the plant. It is conceivable to heat the coating agent directly in a storage container or reservoir or else to achieve the introduction of heat into the coating agent indirectly by heating up parts of the coating device. 
         [0034]    In a preferred development of the invention, the coating agent has a solidifying temperature of over 70° C., preferably of over 85° C., more preferably of over 90° C. 
         [0035]    Such high solidifying temperatures can be advantageously achieved with micro waxes. In this way, a sufficiently high thermal stability of the applied coating for the further processing, filling with the product and later use can be ensured. 
         [0036]    Furthermore, the solidifying temperatures are still chosen low enough to keep down the energy requirement for heating the coating agent, and consequently restrict the complexity of the production and the production plants. Furthermore, protection of the outer surface of the metal package from high thermal loads is ensured. This allows a lacquering, printing or coating that is applied to the outside of the container to be applied already before the sheet-reforming operation, on the flat semifinished product, without being damaged by such thermal loads. 
         [0037]    It is particularly preferred to heat the coating agent after coating once again to a temperature above the solidifying temperature. 
         [0038]    In this way, the applied, already partially or completely solidified coating agent can be partly or fully melted in order to wet the interior space of the metal container completely with the again liquefied or viscous paraffin. This allows wetting of even inaccessible areas in which initial application of the coating agent could not take place. In addition, the integrity and homogeneity of the coating agent and the surface of the coating agent can be improved, since the liquid or viscous coating agent is capable of filling or healing microcracks on its surface or gaps in the application. 
         [0039]    For this purpose, the applied coating agent is preferably brought to a temperature of approximately 100° C. and kept at this temperature for approximately two to three minutes. This can greatly simplify the production process and improve the corrosion protection, since possible defects and cracks in the initial layer can be closed or healed in a dependable way by a subsequent production step. 
         [0040]    In an advantageous development of the invention, during the forming of the metal package there is formed at least one folded seam connection, which is coated with the coating agent during the subsequent coating of the interior space. 
         [0041]    In this way it has been made possible to use reforming and joining processes that are simple, inexpensive and suitable for mass production to form the metal package, since it can be ensured by the coating with a paraffin-based coating agent that even areas that are particularly difficult to access, such as for example seaming channels, can be covered with the coating agent. 
         [0042]    In an advantageous development of the invention, for applying or reheating the coating agent, the metal package is arranged such that it is aligned so as to completely wet the interior space with the coating agent. 
         [0043]    Consequently, with suitable alignment, the applied liquid or viscous coating agent can, under the influence of gravitational force, penetrate of its own accord into areas of the metal package that are difficult to access, such as for example folded seam connections, in order to ensure complete coating of the interior space. It is conceivable to align the metal package a number of times during production, and in this way further increase the reliability of the process in terms of the coating operation, and similarly thereby allow areas that are particularly difficult to access to be wetted with the coating agent. 
         [0044]    For example, in the course of alignment the metal package may be turned by 180 degrees, in order after complete covering of the bottom area of the metal package to then cover the area opposite that dependably with the coating agent. When doing so, any opening there may be in the lid may be suitably closed. It is alternatively conceivable in the course of the coating process to allow excess coating agent to run out of the metal package simply under the effect of gravitational force after it has been suitably aligned. 
         [0045]    In a preferred development of the invention, when applying or re-heating the coating agent, the metal package is pivoted so as to completely wet the interior space with the partly or fully melted coating agent. 
         [0046]    By means of a continuous pivoting movement, it can be achieved in this way that the coating agent is applied particularly dependably and quickly to the entire interior space of the metal package. 
         [0047]    The pivoting movement may take place already during the initial application of the coating agent, but similarly in the course of possible subsequent follow-up steps of heating the applied coating. 
         [0048]    According to a development of the invention, the coating agent is mixed with a solvent for paraffin. 
         [0049]    This can bring about the effect that the viscosity of the coating agent and the processing temperature for applying the coating agent are lowered. This allows energy savings to be achieved, since the coating agent does not first have to be brought to a higher processing temperature. Furthermore, by adding solvents to the coating agent, further process-relevant properties can be suitably influenced. It is conceivable for the creep of the coating agent or the adhesion on the specific sheet material to be improved. 
         [0050]    It goes without saying that non-toxic and unharmful solvents should preferably be used. It is alternatively conceivable for it to be possible to use other solvents that have an outstanding dissolving effect in the case of paraffins, such as for example benzene, ether and chloroform. It also goes without saying that the solvents should escape completely after application, after which the coating agent can have the advantageous properties of almost pure or completely pure paraffin. 
         [0051]    It should be noted in this connection that the proportion of paraffin in the coating agent may be altered by constituents undergoing degassing or other releasing processes, in any event may be greater after the production of the metal package than before the application of the coating agent. 
         [0052]    It goes without saying that the features of the invention mentioned above and still to be explained below can be used not only in the respectively specified combination but also in other combinations or on their own without departing from the scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0053]    Further features and advantages of the invention emerge from the following description of a number of preferred exemplary embodiments with reference to the drawings, in which: 
           [0054]      FIG. 1  shows a perspective representation of a partially cut-open metal package according to the invention in the form of a barrel; 
           [0055]      FIG. 2  shows a perspective view of a further metal package according to the invention in the form of a can; 
           [0056]      FIG. 3  shows a perspective representation of a further metal package according to the invention in the form of a canister; 
           [0057]      FIG. 4  shows a section through a metal package according to the invention with a seamed lid; 
           [0058]      FIG. 5  shows a schematic representation of an installation for coating the interior space of a metal package using the method according to the invention; 
           [0059]      FIG. 6  shows a view of a nozzle for use in the method according to the invention; 
           [0060]      FIG. 7  shows a partial section of an embodiment of a nozzle that has been modified in comparison with  FIG. 6 ; 
           [0061]      FIG. 8  shows a schematic partial view of an embodiment of an installation for coating a metal container that has been modified in comparison with  FIG. 5 ; 
           [0062]      FIG. 9  shows an enlarged partial section through a metal package according to the invention in the area of a folded seam connection with an applied coating agent; 
           [0063]      FIG. 10  shows a view according to  FIG. 9  with an interior space of the metal container that has been completely wetted by a partly or completely melted coating agent; and 
           [0064]      FIG. 11  shows a schematic representation of a pivoting device for pivoting or aligning a metal container according to the invention when carrying out the method according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0065]    In  FIG. 1 , a metal package according to the invention in the form of a barrel is represented and denoted as a whole by  10 . 
         [0066]    Such metal packages are widely used for packaging and storing chemical or technical products or else foodstuffs, in particular beverages. Packages of such a design have found widespread use as beer barrels. In general, such beer barrels have a filling volume from approximately three to approximately twenty liters, barrels known as 5-liter party barrels having become established as a common container size. However, barrels with a filling volume from just a few liters to several hundred liters are offered primarily for wholesale demand and for chemical or technical products. 
         [0067]    Metal packages of such a design are usually formed from thin or very thin metal sheets. Usually, very thin sheets have thicknesses of less than 0.5 millimeter, while thin sheets cover approximately the thickness range from 0.5 to 3 millimeters. Materials and semifinished products for producing such metal packages are flat strips, plates and coils of tin plate, non-tin plate or else special electrolytically chrome-coated steel sheet. 
         [0068]    The metal package  10  shown in  FIG. 1  is fashioned from the flat material by various re-forming and joining operations. The metal package  10  has a shell element  15 , which surrounds an interior space  12  and is connected in its lower area to a bottom element  11  and in its upper area to a lid element  13  by means of folded seam connections  17 . The lid element  13  has a filling opening  16 , for example for filling with beer. The bottom element  11  and the lid element  13  may be formed, for example, from pre-punched round blanks. The shell element  15  is formed from flat strip, the cylindrical form being produced by bending over and joining two ends of the substantially rectangular starting material by means of a folded seam connection (not represented). It is alternatively conceivable to form the shell element  15  from a tubular semifinished product. 
         [0069]    A metal package according to the invention may well have in addition to the filling opening  16  further openings, such as for example for integrating a tap cock or for aerating or venting. 
         [0070]    In the course of shaping such a container, many separating, joining or reforming processes may be used, such as in particular punching, cutting, expanding, flanging, seaming, welding or beading. 
         [0071]    It should be noted in this connection that the term “metal package” must not be understood as implying that the finished package or the filled container does not have any non-metal component parts. It is normal and conceivable to provide plastic-based closures, valves or transporting aids, such as handles or edge protectors, and so “metal package” should not be understood restrictively in this respect. 
         [0072]      FIG. 2  shows a further metal package  10   a  according to the invention. By contrast with the metal package  10  that is represented in  FIG. 1 , the metal package  10   a  in  FIG. 2  is represented in a one-part state. The shell element  15  may be formed by expanding or deep-drawing a flat or preformed semifinished product. The form of container that is shown in  FIG. 2  usually serves for receiving carbonated beverages, in particular beer or cola, but is also used for filling with other products. Such packages, known in the form of beverage cans, may be made of the aforementioned steel sheets, alternatively of aluminum sheets, but also of a combination of metal material. Widely used filling capacities are for instance 0.2, 0.25, 0.33, 0.5, 0.75, 1.0 and 1.5 liters. 
         [0073]    The usual form of a beer or cola can with a metal single-use closure gives rise to a special technical feature in terms of production or filling; that is that a lid element (not represented in  FIG. 2 ) is only connected to the shell element  15  after the product has been introduced through the filling element  15  of the metal package  10   a.    
         [0074]    A further modified embodiment of a metal package according to the invention is shown in  FIG. 3  and is denoted by  10   b . The metal package  10   b  in the form of a canister may serve for receiving liquid chemical products, such as for example paint or varnishes, but also for storing free-flowing granules or powder. In the foodstuffs sector, such containers are used for applications including the storing of edible oil. 
         [0075]    In a configuration given by way of example, the metal package  10   b  has a shell element  15 , which also bounds the bottom area of the metal package  10   b , so that all that is additionally provided is a lid element  13 , which is connected to the shell element  15  by way of a folded seam connection  17 . In an alternative refinement, such a canister may also have an additional folded seam connection for receiving a bottom element, for instance by analogy with  FIG. 1 . 
         [0076]    In  FIG. 4 , a further metal package  10   c  is represented. The sectional view clearly shows the configuration of the folded seam connection  17  for connecting the lid element  13  to the shell element  15 . It is immediately evident that, to fashion such a folded seam connection in the case of the shell element  15  and the lid element  13 , flanging or seaming operations must be performed, whereby the individual metal sheets are subjected to high degrees of re-forming in these areas. 
         [0077]    It should once again be pointed out that it is known in the prior art to provide the sheets that are used with coatings, such as for example decorative lacquerings or printings or corrosion protection agents, either in the flat state before the re-forming or else in the re-formed or joined state. In the areas of the sheets that have high degrees of re-forming, these coatings may be weakened or damaged by these operations if they are applied before the re-forming or joining. 
         [0078]    This disadvantage can be obviated by alternative or additional coating of the metal package, in particular of the interior space of the metal package, after the reforming and joining, although this increases the complexity of the production and may give rise to other disadvantages. For example, it is known that with the drying of a coating or lacquering applied to the interior space  12  of the metal package  10   c , which in the case of conventional lacquers is performed at high temperatures of approximately 180 to 200° C., a decorative lacquering applied on the outer side  18  of the metal package  10   c  may be impaired or damaged by discolorations or the like. 
         [0079]    Alternatively, by omitting this additional inner coating, a reduced corrosion protection would have to be accepted in the interior space  12  of the metal container  10   c , and there in particular in the area in which individual elements come together to form a folded seam connection. 
         [0080]    To avoid such disadvantages, it is thus proposed according to the invention to apply a coating with a paraffin-based coating agent in the interior space of a metal package. 
         [0081]      FIG. 5  shows a schematic representation of an installation for carrying out the method according to the invention. 
         [0082]    A metal package  10 , represented in a simplified state and formed for instance according to  FIGS. 1 to 4  is arranged in relation to a coating device denoted by  20 . Here it is conceivable for the feeding movement and further possible relative movements of the metal package  10  with respect to the coating device  20  to be produced by a handling device that is schematically represented in  FIG. 5  and denoted as a whole by  40 . The handling device may have lifting means or turning means, as indicated by the arrows  46  and  44 , respectively, in order to move the metal package  10  in relation to a nozzle part  24 . 
         [0083]    Alternatively, it is conceivable to move the coating device  20 , or at least a feeding means  22  assigned thereto and having the nozzle part  24 , in relation to the metal package, which will be explained in more detail later with reference to  FIG. 8 . 
         [0084]    The feeding element  22  serves for supplying the nozzle  24  with the coating agent  30 . Provided for this purpose are lines  28 , configured in  FIG. 5  by way of example as a ring line. It goes without saying that the feeding element  22  may have a valve suitable for controlling the coating operation (not represented). The line  28  connects a container means  34 , which serves for receiving a supply of the coating agent  30 , to the nozzle part  24 , it being possible for excess coating agent that is not applied to be introduced once again into the container means by way of a return. A pump  35  in the line  28  serves for generating the pressure for applying the coating agent  30 . 
         [0085]    Before being applied, the coating agent  30  is advantageously heated or liquefied by means of heating devices  32  or  32   a . The heating device  32  may serve for heating the coating agent  30  when it flows through the line  28 . Additionally shown is a heating device  32   a , which serves the purpose of heating the coating agent  30  located in the container means  34 , so that the target temperature of the coating agent  30  can alternatively be ensured by permanent circulation in the line  28  by means of the pump  35 . 
         [0086]    In  FIGS. 6 and 7 , design developments of the feeding means  22  are represented. Here, the nozzle part  24   a  in  FIG. 6  has a spherical shape, thereby ensuring that virtually the entire space surrounding the nozzle part  24   a  can be wetted with a coating agent. 
         [0087]    On the other hand, in  FIG. 7  the nozzle part  24   b  is additionally provided with a joint  26 , which makes it possible for the nozzle part  24   b  to be additionally pivoted, in order to be able to coat areas of a metal package that are difficult to access. 
         [0088]    According to the arrangement in  FIG. 5 , it is sufficient to move the metal package  10  in an axis  46  in relation to the nozzle part  24  in order to be able to achieve complete wetting of the interior space  12  of the metal package  10 . A rotation  44  may be additionally introduced in order to bring about a uniform distribution of the coating agent  30  over the circumference of the interior space  12  of the metal package  10 . 
         [0089]    By contrast with this, schematically represented in  FIG. 8  is a metal package  10  which has only a relatively small filling opening  16 . This may make it more difficult in particular to coat corner areas of the interior space  12  of the metal package  10 . This is so particularly when a directed nozzle part  24  is used, for instance a nozzle with an emission angle of only 90 degrees or 180 degrees. 
         [0090]    To overcome such disadvantages, in  FIG. 8  there is provided an alternative handling device  40   a , which serves for advancing a feeding means  22   a  with the nozzle part  24  into the interior space  12  of the metal package  10 . The handling device  40   a  may have lifting means or turning means, as indicated by the arrows  46   a  and  44   a , respectively. In this way, the feeding means  22   a  can be introduced into the interior space  12  and also moved there. For the fine alignment of the nozzle part  34 , further joints  26   a ,  26   b  are provided. By combining the handling device  40   a  with the feeding means  22   a  it is thus possible to wet almost the entire interior space  12  of the metal package  10 . 
         [0091]    A particularly advantageous method step is then illustrated in  FIGS. 9 and 10 . 
         [0092]    An area of a folded seam connection  17  between a bottom element  11  and a shell element  15  of a metal package is respectively shown in section in these figures. This detail may be representative of areas of further folded seam connections, more generally of areas of a metal package that are difficult to access. These may also be, in particular, lid seams or lateral vertical seams and any areas that are not wetted in the course of the initial coating. 
         [0093]    The initially applied coating agent  30 ′ is shown in  FIG. 9 . It can be seen here that the area in which the shell element  15  and the bottom element  11  come together to go into a folded seam connection, known as a seaming channel  19 , is possibly not covered completely by the coating agent on account of its narrowness and depth. However, the coating agent  30 ′ according to the invention can be partly or fully melted particularly easily at relatively low temperatures by suitably supplying heat, indicated by  38 . For this purpose, a melting device  36  is thus used for generating the heat input  38 . The heat input  38  may advantageously take place by way of convection, heat conduction and by way of radiation into or around the metal package, for example by means of circulation of heated air or else by infrared radiation, in particular near infrared radiation. It is particularly advantageous in terms of production to make the coating agent  30 ′ that is to be heated melt partly or fully indirectly by heating metal sheet material  14  in the shell element  15  or the bottom element  11 . 
         [0094]    It should especially be mentioned in this connection that the temperatures thereby occurring on the outer side of the metal package are much lower than the temperatures during the drying of conventional lacquers on the inner side of the metal package. This dependably avoids instances of damage, such as for example deviations in color, of the coating of the outer side of the package. 
         [0095]      FIG. 10  then illustrates the desired state aimed for, in which the coating agent then denoted by  30 ″ has penetrated of its own accord into the seaming channel  19  and completely wetted it. Dependable corrosion protection and later separation of the product from the sheet metal material  14  of the metal package  10  is consequently also ensured in this area. The partly or fully melted coating agent  30 ″ is sufficiently viscous to ensure that, in spite of running of its own accord under the effect of gravitational force, areas once wetted are not exposed again. 
         [0096]    This particularly preferred method step is also suitable in particular for dependably coating inaccessible areas on outer sides of metal packages. These may be, for example, pronounced depressions, beads or outer seam geometries. As is known, metal containers tend to corrode specifically in such areas. 
         [0097]    In order to assist penetration of the coating agent into areas of the interior space of the metal package that are difficult to access, or make it possible in the first place, it is particularly advantageous to align or pivot the metal package suitably, so that the entire interior area can also actually be wetted by means of gravitationally induced flowing. 
         [0098]      FIG. 11  schematically shows a pivoting device suitable for this, which is denoted as a whole by  42 . The pivoting device  42  is provided with various pivoting or turning axes  52 ,  54 ,  56  and  58 . Also provided are gripping means  50 , to allow the metal package  10  to be gripped and held. By means of the pivoting device  42 , the metal package  10  can then be suitably aligned or pivoted in order to direct or help the flowing of the coating agent. This pivoting or aligning may be performed both discretely and continuously. It is thus conceivable to move the metal package  10  already during the heating of the applied coating agent in such a suitable way as to keep the process time short. 
         [0099]    As an example of discrete alignment of a metal package  10 , it is conceivable to heat a container, for instance according to  FIG. 1 , after the initial application of coating agent in a position in which the bottom element  11  is on the ground, so that the coating agent can penetrate of its own accord into the seaming channel of the folded seam connection  17  between the bottom element  11  and the shell element  15 . After that, the metal package  10  may simply be turned by 180 degrees, so that the coating agent  30 , which is still in the partly or fully melted state, or is brought once again into this state by re-heating, can also penetrate into the seaming channel between the lid element  13  and the shell element  15 . When doing so, the inlet opening  16  may be suitably closed, in order to avoid flowing out of the molten coating agent  30 . 
         [0100]    It is similarly conceivable to introduce a greater amount of coating agent into a metal package, deliberately allow it to flow around in the interior space of the metal package and subsequently pour out of the metal package an excess amount of the coating agent that is not required. 
         [0101]    It goes without saying that the handling, pivoting and feeding devices shown can be suitably combined, reduced and simplified in order to make the plant for carrying out the method according to the invention as simple and inexpensive as possible and allow it to be integrated in the established production sequence in the production of metal containers. 
         [0102]    It has been accomplished within the scope of the invention to provide a particularly simple and effective method for producing metal packages in which, in particular, corrosion protection in the interior space of the metal packages is ensured to an improved extent with at the same time less complex production and at the same time improved production quality. 
         [0103]    A metal package according to the invention accordingly ensures high corrosion protection along with a simplified way in which it can be produced, particularly also meeting the requirements for suitability for food contact applications.