WO1994021519A2

WO1994021519A2 - Foodstuff package, process and device for manufacturing an oxygen-tight package, row of shells used therefor

Info

Publication number: WO1994021519A2
Application number: PCT/EP1994/000797
Authority: WO
Inventors: Jochen Dietrich
Original assignee: Jochen Dietrich
Priority date: 1993-03-18
Filing date: 1994-03-15
Publication date: 1994-09-29
Also published as: WO1994021519A3

Abstract

A foodstuff package is designed as a dimensionally stable preformed shell with an upper continuous marginal flange for hermetically sealing the inside of the container together with a preferably oxygen-proofing covering foil. The shell consists of ground cellulose or wood pulp and carries on its inner surface, as well as in the area of the marginal flange, an oxygen-proofing plastic composite foil suitable for sealing together with the covering foil. Also disclosed are a process and device for producing an oxygen-tight package. Preformed and dimensionally stable container shells are supplied by a dispenser. The shells are lined with a plastic composite foil in a forming station. In order to increase their stability, the shells of a row of shells are interconnected in a single piece by connecting elements which coincide with the marginal flanges of the containers, so that the shells successively and synchronically run through the packaging installation and are sealed all together.

Description

Food packaging, process for the production of an oxygen-tight packaging,

Device for carrying out such a method and row of shells used

The invention relates to a food packaging according to the preamble of patent claim 1, as well as a method for producing such a packaging, a device for carrying out such a method according to the preamble of patent claim 13 and a semifinished product suitable for this in the form of a row of trays.

Food packaging is on the market in a great variety, with special efforts being made recently to minimize the proportion of non-recyclable plastic in such packaging. So far, food packaging in the form of deep-drawn plastic trays, which generally have a carrier material which consists, for example, of polyvinyl chloride, polyester or polystyrene, has prevailed. These trays are regularly deep-drawn in the packaging machine and then pass through a filling station before they reach the vacuuming and sealing station. The advantage of this packaging is that the packaging device can be constructed in a clear manner, and a modular arrangement of the device is also possible.

Attempts have also already been made to reduce the proportion of plastic in such packaging by using coated cardboard. Here, however, it has been found that it is difficult to process these materials in devices in which largely known or already existing modules are used. In addition, those made of coated Cardboard pressed containers limit the maximum mold depths to 25-30 mm and the containers produced in the pressing process must be fed individually to the packaging systems.

Even if it is possible to make the cardboard container walls largely oxygen-tight by means of a barrier layer lamination, folds are formed in the radii due to the cold compression molding process due to the material displacement that has occurred. These foldings extend as far as the edge flange area of the packaging, as a result of which a secure and tight seal with the cover film is impossible.

To e.g. To produce tray depths of more than 30 mm depth, containers made of coated cardboard are used, which are formed from blanks. These blanks made from oxygen-tightly coated cardboard on a separate unit are erected, that is, folded and glued, and must also be fed individually. However, it is not possible to connect such containers made from blanks at the cutting or gluing points in a gas-tight or oxygen-tight manner.

Thus, the oxygen tightness that can be achieved with such coated cartons is often not sufficient, and the difficulty that has arisen, particularly in the area of the vacuuming and sealing station, is that an excessive volume has to be subjected to the vacuum.

In the case of conventional shells made of PVC, polyester or polystyrene, a very uneven distribution of thickness in the area of the base radii occurs on vacuum forming and filling systems for production reasons. This very often leads to so-called kink breaks during transport. Whereas when using shells made of wood fiber mass or Cellulose, which are produced in the original form, this can be excluded.

In addition, series tests have shown that a barrier layer made of polyvinyl alcohol, which achieves the required oxygen tightness and is embedded in hard film, shows a significantly poorer molding result, that is to say it has lower residual wall thicknesses than an even thinner one embedded in soft film Layer shows. In contrast, however, the thickness distribution and thus the oxygen barrier layer is also significantly improved in the area of the base radii.

In the prior art, it has accordingly proven necessary to coat the plastic carrier material of the shells, which is responsible for the dimensional stability, with a further plastic material to ensure sufficient oxygen tightness. This plastic layer regularly consists of an ethylene-vinyl alcohol system. In addition, a third layer was necessary to enable sealing with the cover film. This leads to a multi-layer film structure consisting of various components, which makes recycling, that is to say reprocessing by type, impossible.

However, there is a need to create a food packaging according to the preamble of patent claim 1, which can be produced with little change-over effort on conventional, horizontal molding, filling and closing systems, the proportion of plastic being reduced to a minimum, at the same time however, the stability of the packaging and the oxygen density should be kept at an unchanged high level.

Another task is to develop a process for the oxygen-tight packaging of food with the aid of development of a food packaging of the above type in such a way that conventional, modular packaging systems with a higher cycle rate and thus can be operated more economically.

Finally, an object of the invention is to adapt the device for carrying out the above-mentioned facts to the packaging according to the invention in such a way that the susceptibility to failure of the packaging system is minimized even at the highest number of cycles.

This object is achieved in terms of food packaging by the features of claim 1, in terms of the method by the features of claim 7 and in terms of the device by the features of claim 13 and a semi-finished product suitable for this in the form of a row of trays.

The food packaging according to the invention has a wood base or cellulose shell lined with an extremely thin plastic composite film as the load-bearing base, which is produced using the deep-drawing process. This production in the long-established forming process can, due to the wall and floor-forming mold, be reliably ruled out that the inner walls of the shell or the bottom of the shell form sharp or pointed corners or edges, which is the case with containers made from cardboard blanks or with Cardboard trays formed in the cold pressing process cannot be excluded. Accordingly, the coating can nestle against the inner wall of the shell in all areas. As a result, the inner coating can be made very thin, which is further promoted by the fact that the shell wall reliably shields the plastic lining from mechanical influences which, based on experience, only act on the food packaging from the outside. Advantageous embodiments of the packaging are the subject of dependent claims 2 to 6.

Due to the choice according to the invention of the plastic-lined cellulose or wood pulp shell, there is a container which is oxygen-tight up to one side when it enters the vacuuming and sealing station, namely the upper side. In addition, because the plastic-lined shell also has a very high dimensional stability in the area of the peripheral edge flange, the edge flange can be securely accommodated between the seals of the closed vacuum and sealing tool, so that according to the invention only the Inner cavity of the deep-drawn shell must be evacuated. The power consumption of the packaging system is reduced and additional time is saved in the work cycle.

The number of cycles of the machine can be increased considerably if, according to patent claim 8, the deep-drawn, dimensionally stable cellulose or wood pulp trays are not isolated, but are fed in continuous rows from a dispenser. It has been shown that the saddle webs formed between the adjacent shells have a sufficiently high stability to reliably rule out, despite lateral attack of a transport or conveying device, that even if the shells are filled with several foods, an uncontrolled breakage or an uncontrolled tearing of the webs follows.

The operational reliability of the device can additionally be increased by supporting the saddle webs between the shells from below by means of slide or guide rails aligned parallel to the transport direction. The further development according to which the containers are filled in the filling is also advantageous. distance are supported from below by means of a support belt running synchronously with the transport device.

Advantageous developments of the invention are the subject of the remaining subclaims.

These further developments result in particular in the advantages of a further simplification of the packaging system, since no separate deep-drawing stamp devices are now required. The preheating section previously required can also be omitted without replacement. Nonetheless, the throughput section required for this can be used according to the invention for accommodating the filling station, thereby additionally saving space. Either the machine as a whole is considerably shorter or the filling station can be made longer than before, which makes the packaging process easier.

With the food packaging according to the invention, the proportion of non-recyclable plastic can be reduced to a minimum, the additional advantage of problem-free self-rotting resulting from the choice of material for the tray according to the invention.

Finally, the power consumption of the machine in the area of the vacuuming and sealing station is also reduced, since on the one hand the cycle frequency can be reduced by the row-by-row sealing and on the other hand the vacuum in the shell can be produced more quickly than before because the design according to the invention the shells lead to very high inherent stability.

Further advantageous embodiments are the subject of the remaining subclaims.

An exemplary embodiment of the invention is explained in more detail below with the aid of schematic drawings. Show it: 1 shows a schematic side view of a first embodiment of the packaging system according to the invention;

2 shows a perspective view of a row of shells;

3 on an enlarged scale the area of the packaging system at the inlet of the row of trays;

4 shows the molding station of the packaging system on an enlarged scale;

Fig. 5 is a front view of that shown in Fig. 4

Forming station with inserted row of shells and plastic composite film;

6 is a perspective view of the row of shells with a plastic composite film, the edge flange area with a plastic composite film being shown on a somewhat enlarged scale along the line of the row of shells indicated by the arrow;

7 shows a front view of the sealing station with the row of trays inserted;

8 shows a perspective view of the row of shells with plastic composite film and cover film, the details being shown more clearly on an enlarged scale;

9 is a perspective view of a ready-to-use or consumable device according to the invention

Bowl; 10 shows a perspective view of the shell according to the invention with the lid or plastic composite film partially detached; and

11 is a perspective view of the shell according to the invention with the cover film partially peeled off.

1 shows the side view of a packaging system which essentially consists of three stations, namely a molding station FS, a filling section BS and a two-stage separating system 80, 81, the latter also being able to be designed in one stage. The row of shells is transported to the individual stations via a conveyor belt or a conveyor chain 48, support belts 50 being additionally provided for relieving the conveyor chain in sections.

The rows of shells 40 collected in a dispenser 10 are released, for example, from the bottom of the dispenser 10 and picked up or caught by a transport shoe 56. The row of shells 40 lying there is pushed into the effective area of the transport chain 48 by a piston / cylinder arrangement 62, which remains in its basic position 60, in cooperation with the transport shoe 56. The transport shoe 56 only bridges the distance ST between the dispenser 10 and the entry point of the row of shells 40 into the grippers 46 of the transport chain 48 by approximately 50%. To cover the remaining distance of the row of shells 40, the additionally provided ejection device is preferably used in the form of a pneumatically driven piston / cylinder arrangement which is operated in time with the transport chain 48. The tray rows 40 now located on the transport chain 48 are then fed to a molding station FS for lining the inner surfaces of the tray rows with an oxygen-blocking plastic composite film or barrier layer composite film 34. The Plastic composite film 34 is drawn from an endless roll 33, which is fastened on a support arm above the inlet section of the machine, via deflection rolls over the inserted rows of shells 40. In order to avoid uncontrolled running of the plastic composite film 34 from the endless roll 33, a brake arm is of course built into the feed path of the barrier layer composite film 34, as is generally the case. Another deflection roller is mounted above the transport chain in such a way that the plastic composite film 34 is drawn into the molding station FS essentially parallel to the transport plane. The transport chain now guides the still empty rows of trays 40, which are covered by the sealed plastic composite film 34, under the molding station FS, the method of operation for lining the inner surface of the row of trays with the plastic composite film 34 in detail with reference to FIG. 4 ter is described.

The packaging trays are then transported by means of the transport chain 48 into the area of a filling station, the filling section BS being designed according to the number of filling steps. In order to relieve the load on the transport chain 48, the row of shells 40 is supported by a support belt 50, which works in synchronism with the transport chain. The filled trays run from the filling section BS into a vacuuming and sealing station VS, at the same time a cover film 20 guided by an endless roll 22 via a deflection roller system is fed into the vacuuming and sealing station VS essentially parallel to the transport section. The mode of operation of the vacuuming and sealing station VS will be described in detail by means of FIG. 7. After the packaging trays have been sealed, they are again conveyed to the separating stations 80 and 81 by means of the transport chain 48, the row of trays again being supported by a conveyor belt 50 operating in the same cycle. As can also be seen in FIG. 1, the transport path of the transport chain 48 and the support belt '→ O extends from the dispenser 10 to immediately behind the two-stage singling station 80, 81, so that the entire system operates in synchronism.

The peculiarity of the packaging system is that on the one hand a specially constructed tray is used and on the other hand the tray is fed to the packaging system in a special way, namely as a specially designed semi-finished product.

Contrary to conventional designs of such packaging systems, the dispenser 10 feeds an already preformed, dimensionally stable shell with an edge flange 24 on the top, the shell having cellulose or ground wood as the carrier material 26. The row of shells 40 is pressed, for example, into the shape shown in FIG. 2, which results in a very high degree of inherent stability even with relatively small wall thicknesses, which is additionally improved by the edge flange 24. The edge flange 24 preferably merges into the side walls 28 of the shell 12a, 12b, 12c via a curve 30. Similarly, a curve is provided in the transition from the side walls 28 to the bottom wall 32.

The semi-finished strips or tray row 40 fed to the packaging machine have at least two trays 12a-12c lying next to one another (see FIG. 2). For this purpose, the dispenser 10 is equipped with a corresponding width. The preformed shells 12a, 12b, 12c also each have a circumferential edge flange 24 and are integrally connected to one another via saddle webs 42. The lateral edge flanges 24a have a width B44 sufficient for the attacking transport and gripping device plus a minimum width B24 for a sufficient width safe sealing surface. The saddle webs 42 have a width B42 which is sufficiently large to be able to bring about a continuous welding surface with the cover film 20 which is sufficient from the sealing surface. The width B42 of the saddle bars 42 usually corresponds to twice the size of a safe minimum seal area. This width B42 is preferably in the range between 8 and 12 mm. The width BQ of the edge flange 24a of the outer shells 12a and 12c transverse to the transport direction T is kept somewhat larger and is preferably in the range between 10 and 14 mm. This is because this edge flange 24 * is used to transport the row of trays through the packaging system. The rear edge flange 24b of the shells 12a, 12b, 12c seen in the direction of transport has an expanded width of a total of 14 to 18 mm, since a punched-out or grip recess GM is provided centrally with respect to the shells 12a, 12b, 12c , which is suitable for later formation of the grip tab for detaching the film composite from the carrier material 26.

The outer region 44, which is indicated in FIG. 2 by a dash-dotted line, is reserved for the engagement of grippers or gripping links 46 of the transport chain 48 which are in mutually predetermined longitudinal sections. The circumferential edge flange and the structure of the Shells 12a-12c resulting in a high dimensional stability of the row of shells 40 has proven to be particularly reliable in order to reliably exclude cracks in the containers or in the edge flanges even in the case of larger cycle numbers, even in the area of the handle recess GM. In this way, the design of the food container or the packaging system according to the invention is also suitable for producing packaging with a relatively high weight. In order to keep deflections of the row of shells even smaller, especially when filled, it can be advantageous to pass the saddle webs 42 through from below Support guide or support rails. As an alternative or in addition to this, support belts 50 can be provided in the area of the filling section BS under the row of shells 40, which are driven in the same cycle as the transport chain 48.

FIG. 3 shows the area on an enlarged scale at which the tray strips 40 fed via the dispenser 10 are transferred to the transport chain 48. It can be seen that a transport shoe 56 is arranged below the dispenser 10 and can be aligned with respect to the height of the axis 57 of the deflection roller 52. The rows of shells 40 rest on the transport shoe 56 after, for example, the bottom-side release of the dispenser 10. The transport shoe 56 preferably carries an ejection aid or ejection device 62 in the form of, for example, a pneumatically driven piston / cylinder arrangement, via an upwardly angled edge. The transport shoe and the ejection device 62 are driven in such a way that each of these two units only covers half the cycle path of the gradual transport. That is to say, the transport shoe 56 is moved to the left in cycles by half the cycle path according to FIG. 3. The co-moving ejector 62 then performs the second half of the cycle path by actuating the piston / cylinder arrangement. 3 that the grippers 46 seated on the transport chain 48 are opened just before they leave the deflection roller 42. The rows of shells 40 moved to the left by the transport shoe 56 and the ejection device 62 according to FIG. 3 can thus be moved into the open chain links 46 without any problems. By suitable synchronization of these movements, the edge regions 44 of the row of shells 40 are then detected at the correct time when the chain links are closed again, whereupon the row of shells 40 are transported by the conveyor chain 48. The arrangement of the deflection roller 52 according to the invention makes it possible to use the movement of this deflection roller 52 to control the movement of the chain links. Here, for example, or preferably a cam control is used, ie the three chain links 46 are opened when they run onto a cam shortly before leaving the deflection roller 52 and closed again when the cam moves further, so that the row of shells is firmly gripped.

4 shows how the tool halves 16 and 18 interact with the row of shells 40 in the molding station in order to line the inner surfaces of the row of shells 40 with the plastic composite film 34 by means of a heating device 72. The insert shown in FIG. 4 shows the location of the packaging station of the forming station FS as a reminder.

The tool of the forming station FS consists of a lower mold 16 and an upper mold 18, which are moved apart and moved clocked in accordance with the arrow shown in FIG. 4, the lower mold 16 preferably having a profile for positively receiving the shells 12, so that the edge flanges 24 of the shells 12 are supported in a sealed manner. The upper mold 18 is also designed so that a heating device 72 can be accommodated. The heating device can be designed as a heating plate in such a way that in the rear part of the heating plate, when viewed in the direction of transport, there is an area 73 which, when the molding station FS is in the closed state, has no or only a small amount of heat transfer to the plastic composite film 34 located therebetween and edge flange 24.

FIG. 5 shows the front view of the molding station, the lower mold 16 having web-like inserts 66, the shape of which corresponds to the cross section of the shell strip 40 is adapted so that when the tool halves 16 and 18 are moved together, the shell or the individual shells 12A, 12B, 12C are additionally positively supported by the mold insert 58 provided, the surface contour of which corresponds to the shape of the individual shells. In addition, individual passages VK are provided in the bottom of the lower part and through the mold insert, which are connected to a pump system for generating a negative pressure.

The functioning of the forming station FS will be described in detail below. If a row of shells 40 is now introduced and aligned into the forming station FS by the gripping links 46 of the transport chain 48, the lower part 16 of the forming station, which was previously extended downward, moves in the direction of the arrow, for example upward via toggle levers (not shown). When the lower part 16 of the tool moves together against the upper part 18 of the mold, the entire interior of the molding tool of the forming station FS is sealed off by the all-round, approximately 3 mm thick silicone cord 70E embedded in the lower part 16. The plastic composite film 34 lying above the row of shells 40 is held in place by this closing cycle. At the same time, the relief-like configuration of the heating plate 72 is pressed against the silicone seals 70 in the lower tool part 16. In this case, the contact pressure and heat connect the plastic composite film 34 located between the tool parts 16 and 18 over the edge flanges 24 and the saddle bars 42 to these sealing surfaces. With a vacuum, possibly also a vacuum, the plastic composite film 34 is simultaneously sucked against the heating plate 72 in the exposed area of the shell recesses 12A, 12B, 12C for plastic heating.

The tool is then briefly vented, the vacuum or the vacuum is switched to the lower tool part 16 and the plastically heated barrier film 34 is now sucked into the bottom area UB of the row of shells 40 via the vacuum channels VK. Although the bottom of the shell is air-permeable, small pinholes could additionally be provided in the bottom radius of the shells 12, which could support the suction by vacuum. In order not to adversely affect the stability of the shell bottom, the pinholes could be introduced into the more rounded curves of the shells 12A, 12B, 12C.

Now that the inner surface of the row of shells 40 is lined with the plastic composite film, the molding tool of the molding station FS is ventilated, the molding station FS opens at the same time by lowering the lower tool part 16, whereby the row of shells 40 is released and for filling by means of the transport chain 48 is carried on.

In Fig. 6 the row of shells is shown as it leaves the molding station. It is almost completely lined with the plastic composite film 34. Only the lateral edge section on which the grippers 46 of the transport chain 48 engage is not covered. As can also be seen, the plastic composite film 34 also covers the handle recess. Since the area 73 of the heating plate can be matched to the handle recess GM, there is no deformation of the area of the plastic composite film 34 that is not supported by the edge flange 24. In the sectional drawing likewise shown along the edge flange of the row of shells 40 with plastic lying thereon Composite film 34 shows the respective layers 36, 37, 38 containing the plastic composite film. The plastic composite film 34 has an oxygen barrier layer 36 preferably made of polyvinyl alcohol and a sealing layer 38 preferably made of peelable polyethylene and an adhesive layer 37 preferably made of the modified Surlyn A type of polyethylene. It has been shown that the inner coating of the shells 12 forming carrier material 26 can be made extremely thin. The thickness is preferably in the range between 10 and 15 micrometers. The plastic composite film can moreover be constructed and its behavior controlled so that it can be removed from the cellulose or wood pulp carrier after use of the packaging, so that pure components are available for disposal or recycling. According to the invention, the handle recess GM serves this purpose.

After leaving the molding station, the trays 12a, 12b, 12c pass through the filling station along the filling line BS, during which they are filled with the foodstuffs to be packaged, the trays being transported through the entire system at intervals. The filled trays run from the filling section into the vacuumization and sealing station VS, in which they are positioned in a precisely aligned manner by the lower part 16 by means of the mold insert 58 and web-like inserts 66. The tool consists of a lower mold 16 and an upper mold 18, which are moved apart and moved together in a clocked manner, the lower mold 16 preferably having a profile for the positive reception of the shells 12 in such a way that edge flanges of the shells 12 are supported in a sealed manner. The upper mold 18 is designed in such a way that it can receive a heating plate 74 which has a line pattern and can move in the vertical direction. The line pattern is designed in such a way that it defines surface areas at which the shells 12 are to be sealed with the cover film 20. The mode of operation of the sealing station will be explained in more detail below with reference to FIG. 7.

The sealing film 20 runs - as shown in Fig. 1 - from an endless supply roller 22 into the tool gap, the transport of the sealing film 20 taking place in that the lid film is entrained by the adhesion to the already sealed trays 12 and their transport direction is carried out. 7 shows how the tool halves 16 and 18 interact with the row of shells 40 in the vacuuming and sealing station.

Fig. 7 shows that the lower mold 16 has web-like inserts 66, the shape of which is adapted to the cross section of the shell strip 40, so that when the tool halves 16 and 18 are in the retracted state, the shell or the individual shells through the provided mold insert 58, the surface contour of which Corresponds to the shape of the individual shells, are positively supported. 70 denotes seals against which the edge flanges or the saddle webs of the row of shells 40 lie when the tool 16, 18 is moved together, so that the individual shells 12a-12c, which already contain the food in this state, are vacuumed can be. Due to the dimensional stability of the preformed row of shells 40, it is sufficient to generate a vacuum only in the cavity of the shells 12a-12c without running the risk that the shell deforms excessively. 74 denotes heating devices which are accommodated in the upper tool half 18 in accordance with a pattern aligned with the edge webs, so that when the tool halves 16, 18 are moved together, the cover foil 20 is welded to the relevant edge flanges of the individual containers ter 12a-12c takes place in such a way that a circumferential, continuous sealing surface is created. At this point it should be emphasized that this can be a commercially available station, in which, after evacuation, fumigation takes place, for example, with support gas. The heating plate located in the upper part of the tool is preferably designed with relief-shaped sealing webs, the cover film being sealed with the sealing coating of the circumferential edge flange and the saddle webs of the shells by the action of heat and pressure. FIG. 8 shows how the sealed tray row 40 filled with food and the individual trays 12 leave the vacuuming or sealing station VS. As can be seen from the corrugated hatching, almost the entire plastic composite film 34 is welded to the cover film 20. This is illustrated particularly in the elevation drawing shown on a larger scale. The dotted area is intended to represent the part on which the cover film 20 is not welded to the plastic composite film 34. It should be emphasized at this point that the cover film is welded to the plastic film in the area of a gripping recess formed by the trailing edge flange of the shells 12a, 12b, 12c, starting from the inner edge of the edge flange only over a portion of the overlap extending into the handle recess. After leaving the vacuuming and sealing station VS, the shell strips 40 connected via the cover film and plastic composite film are fed to a two-stage singling station 80, 81. In the first stage, the coherent shell strips 40 are separated from one another in such a way that any contours provided on the corner regions of the individual shells 12a, 12b, 12c are also cut. In the second stage 81, the individual shells 12a, 12b, 12c are then separated from one another, it also being possible to carry out the possibly missing roundings at the edge of the shells.

After leaving the two-stage singling station, the individual shells 12a or 12b or 12c are present, as shown in FIG. 9.

With the above arrangement, about 25 g of plastic which can no longer be used can be saved per pack, ie approximately 75% of what is obtained with conventional packaging. From the above description it is furthermore clear that the given shape of the It is also no longer necessary for the trough introduced into the vacuum chamber to evacuate the entire chamber - which was previously required - which serves to hold the filled trough. It is sufficient to evacuate only the volume of the actual product receiving space, namely the preformed shell. The working width of the device is of course not limited. However, it has been shown that the width should be at least 420 mm in order to keep the efficiency of the operation of the device at a particularly high level.

The cover film 20 is preferably likewise made of a plastic composite film which has an oxygen barrier layer which is covered on the side facing the shell 12 by a preferably "peelable" plastic layer, preferably made of polyethylene. This layer is then welded to the sealing layer 38 of the food packaging. On the side facing the heating or sealing element, the oxygen-blocking layer is preferably covered by a heat-blocking layer, which preferably contains polypropylene, in order to ensure sufficient surface or dimensional stability of the sealing film in the vacuuming and sealing station VS. to care. Since the sealing film and also the plastic film of the shell lining facing the sealing film are preferably “peelable”, a connection is created when these film layers are welded, which can largely be peeled by hand without destroying the film surface (FIG. 11).

Of course, deviations from the previously described exemplary embodiments are possible without departing from the basic idea of the invention. So it is of course possible to vary the number of shells per row of shells. It is also conceivable for the dispenser 10 to supply a continuous shell via saddle bars, which are arranged in several rows, ie in a surface pattern are. In this case it is of course necessary to design the cutting tool behind the sealing and vacuuming station accordingly.

In addition, before the rows of trays are introduced into the forming station, it is also conceivable to attach a device with which the tray strips 40 can be sterilized or sterilized. This is advantageously a so-called hydrogen peroxide shower.

On the basis of the method according to the invention used, both in the case of the oxygen-tight inner film and in the case of the oxygen-tight cover film, a composite combination of films from the polyolefin group can be used. This composite combination can be recycled as a monofilm. At the same time, however, the stability of the packaging and the oxygen density of the lower part of the packaging are significantly increased.

A really secure sealing with the container lined with barrier-layer composite film by the barrier-layer cover film is created in that, due to the process, the peripheral edge flanges and the saddle bars form a sealing surface of at least 6 mm for the edge flanges and at least 12 mm for the saddle bars. Since the entire available sealing surface, which is coated with the sealing side of the barrier layer, is available as a sealing surface with the cover film, the individualizing of the packs, which is carried out only after sealing, always ensures a sufficient width of the sealing seam. In the case of individually supplied containers, a uniformly wide and thus secure sealing seam surface cannot be achieved due to tolerances when the containers are fixed in the process. The separation of the oxygen-tight film bag from the actual, stability-giving tray is an essential point of the invention (see FIG. 10). The barrier layer composite film lining the inside of the wood fiber or cellulose tray is connected to the fibers of the inside walls of the container. This connection takes place in a known manner in that the Surlyn adhesive layer, which has become plastic due to heating, is pressed by vacuum onto the container surfaces into which fibers of the container flow.

The barrier layer cover film is firmly connected to the lower part of the package in the sealing station via the peripheral edge flanges and the saddle webs of the row of shells, which, as described in the method, are coated with a sealing layer, after the package has been evacuated and possibly fumigated.

The provided, semi-oval punching of the rear edge flange lying in the transport direction and the corresponding design of the molding tool create the possibility of using a so-called "grip tab" to detach the entire composite from the then pure wood fiber or cellulose shell, which then compostable.

In the application area, the peeling off of the cover film from the sealing bars of the pack is also provided, in order to be able to remove the contents easily and without tools. This can be provided by a special configuration of the sealing tool in the sealing station without major conversion work. In this case, the consumer releases the lid film until the contents can be removed. The inner lining film and the not yet completely peeled lid film are then released from the actual tray together via the handle tab, so that the lid film and the inner layer of the barrier layer are separated from the actual wood fiber or cellulose carrier in a simple manner and according to type can be. The individual materials can thus be returned to their further use.

The invention thus creates a food packaging in the form of a dimensionally stable, preformed shell, with a peripheral peripheral flange on the top, via which the container interior is hermetically sealed by means of a preferably oxygen-blocking cover film. The shell consists of cellulose or wood pulp and carries an oxygen-blocking plastic composite film on the inside and in the area of the edge flange, which is suitable for sealing with the cover film. A method and a device for producing an oxygen-tight packaging are also described, wherein pre-shaped and dimensionally stable container shells are supplied by a dispenser. These shells are lined with a plastic composite film in a molding station. To increase the stability, the shells present in a row of shells are integrally connected to one another via connecting webs which coincide with the edge flanges of the containers, so that the shells pass through the packaging system in synchronized rows and in synchronism and are sealed together.

Claims

1. Food packaging in the form of a dimensionally stable, preformed bowl with a top, circumferential edge flange, via which the container interior is hermetically sealed by means of a preferably oxygen-blocking cover film, characterized in that the bowl (12) consists of cellulose or ground wood, the inside and inside Area of the edge flange (24) is lined with an oxygen-blocking plastic composite film (34) which is suitable for sealing with the cover film (20).

2. Food packaging according to claim 1, characterized in that the plastic composite film (34) has an oxygen barrier layer (36) preferably made of polyvinyl alcohol and a sealing layer (38) preferably made of peelable polyethylene and an adhesive layer (37), preferably made of a modified polyethylene , in particular a copolymer of ethylene with 6% methacrylic acid, which is partially (50%) neutralized with Na or zinc ions (Surlyn A).

3. Food packaging according to claim 1 or 2, characterized in that the cover film (20) is formed by a plastic composite film (34) which, on the side facing the tray, has a preferably peelable plastic layer, preferably made of polyethylene and, above it, at least one oxygen-blocking layer, preferably made of polyvinyl alcohol and a covering heat barrier layer, for example made of polypropylene.

4. Food packaging according to one of claims 1-3, characterized in that the plastic composite film (34) has an initial thickness in the range between 100 and 150 microns depending on the depth of the mold.

5. Food packaging according to one of claims 1-4, characterized in that the plastic composite film (34) lining the shell is identical to the plastic composite film which covers the edge flange (24).

6. Food packaging according to one of claims 1-5, characterized in that the shell (12A, 12B, 12C) consists of a recyclable, preferably compostable wood fiber material or pure cellulose carrier (26).

7. The method for oxygen-tight packaging of food in a food packaging according to one of claims 1-6, in which packaging trays pass through a molding station (FS) and a filling section (BS), which is followed by a vacuuming and sealing station (VS), characterized that the shells (12A, 12B and 12C) are fed as a row (40) to the forming station (FS) via a dispenser (10) by means of a transport shoe (56) and the transport chain (48).

8. The method according to claim 7, characterized in that the shells (12A, 12B, 12C) arranged in a transverse to the transport direction and over the edge flanges (24) and via the formed saddle webs (42) row of shells (40) are supplied, and that the lining of the inner surface of these shells in rows and by means of the entire sealing surface the row (40) covering plastic composite film (34), the transport through the gripping links (46) of the transport chain (48) taking place after the molding of the inner film in cycles to the filling station.

9. The method according to claim 8, characterized in that in the molding station (FS) the plastic composite film (34) is first stitched continuously over the edge flange (24) and preferably over the saddle webs (42) and the lining of the inner surface of the shells (12A , 12B, 12C) then by generating a negative pressure in the area (ÜB) delimited by the underside of the plastic composite film (34) and the inner surface of the shells (12A, 12B, 12C).

10. The method according to claim 9, characterized in that the negative pressure is generated by suction of gas from the area (ÜB) below the row of shells (40).

11. The method according to claim 10, characterized in that the suction takes place through openings in the row of shells (40).

12. The method according to any one of claims 8 to 10, wherein the shells (12A, 12B, 12C) are welded with a cover film (20), characterized in that the cover film (20) with the plastic composite film (34) in Area of a gripping recess (GM) formed by the trailing edge flange of the shells (12A, 12B, 12C), starting from the inner edge of the edge flange (24), only over a partial area (TB) which is welded and extends into the gripping recess to overlap.

13. Device for performing the method according to one of claims 7 - 12 in a device for the clocked transport of the plastic composite film (34) shells lined on the inside by a filling section ( ^BS ), a downstream vacuuming and sealing station (VS) and a singling station (80, 81), characterized in that shells (12A.) Lying at least on two sides and connected via saddle bars (42) , 12B, 12C) in the filling section (BS) can be moved synchronously by means of a clocked moving gripping and transport device (48, 46) and can be fed to the vacuuming and sealing station (VS).

14. The apparatus according to claim 13, characterized in that the gripping and transporting device has a pair of laterally next to the row of shells (40) and synchronously running transport chains (48) or conveyor belts which carry gripping members (46) at predetermined distances. with which the side edges (44) of the row of shells (40) can be fixed when passing through the device.

15. The apparatus according to claim 14, characterized in that the grippers (46) are clock-controlled via an eccentric.

16. Device according to one of claims 13 - 15, characterized in that the row of shells (40) can be fed via a dispenser (10), under which a transport shoe (56) is positioned, the height of which depends on the position of the gripping device (46) the gripping and transport device is coordinated.

17. The device according to one of claims 13 - 16, characterized in that for the saddle webs (42) for

Prevention of uncontrolled deflection of additional supporting and guiding devices, preferably in the form of vertically aligned webs are provided, which are preferably adjustable in height.

18. Device according to one of claims 13 - 17, characterized in that the transport shoe (56) the route

ST bridged only about 50% between the dispenser (10) and the entry point of the row of trays (40) into the grippers (46), and that for the remaining travel of the row of trays (40) a further ejection device (62) preferably in the form a pneumatically driven piston / cylinder arrangement is provided, which is operated in time with the transport device and returns to the end position (60) after the work cycle has ended.

19. Device according to one of claims 13 - 18, characterized in that a deflecting roller (52) for the transport chain or for the conveyor belt (48) is arranged shortly after the dispenser (10) in the direction of passage of the device.

20. The apparatus according to claim 19, characterized in that the movement of the deflection roller (52) for controlling the eccentric for the clocked opening and closing of the grippers (46) is used.

21. Device according to one of claims 13 - 20, characterized in that after taking over the row of shells (40) by the grippers (46) of the transport chain (48) suitable for forming the plastic composite film lining plastic composite film (34) from an endless dispenser roll (33 ), which is arranged essentially vertically above the inlet section, and has a conventional pneumatic or mechanical discharge brake, by means of a deflection roller the edge flanges (24) and the saddle webs (42) of the row of shells (40) are pulled.

22. Device according to one of claims 13 - 21, characterized in that on the edge flanges (24) and

Saddle webs (42) of the row of shells drawn plastic composite film (34) is welded or sealed in a clock-controlled manner by the sealing webs (74) of the forming station (FS) with the edge flanges (24) and the saddle bars (42) of the row of shells (40).

23. Device according to one of claims 13 - 22, characterized in that the plastic composite film (34) connected to the edge flanges (24) and saddle bars (42) is transported endlessly by the clock-controlled forward movement of the gripping and transporting device through the molding station (FS) becomes.

24. The device according to claim 23, characterized in that the plastic composite film (34) by the

The heating plate (72) of the molding or vacuum station (FS) is made plastic and is thus heated and pulled by vacuum into the trough molds (12A, 12B, 12C) of the row of shells (40).

25. The apparatus according to claim 23, characterized in that the per se air-permeable shells (12A, 12B, 12C) in the region of the bottom of the shell for easier and more uniform drawing in of the plastic composite film (34) by the negative pressure applied at discrete points to support the build-up of the negative pressure can have a needle perforation.

26. Device according to one of claims 13 - 25, characterized in that a support belt (50) rotates synchronously with the conveyor belt or the conveyor chain (48) with which the shell strips (40) are supported from below, in particular in and after the filling section (BS).

27. The device according to any one of claims 13 - 26, characterized in that the vacuuming and sealing station (VS) has a lower tool part (16) for the shape-accurate reception of the row of shells (40) and a heated upper tool part (18) with which the The roll (22) of the cover film (20) which runs continuously into the opened tool can be pressed against the saddle webs (42) or the peripheral edge flanges and can be welded to the coating of the plastic composite film (34) under the action of heat.

28. Connected row of shells (40) of deep-drawn, dimensionally stable, preformed shells (12 A, B, C), each of which has a peripheral edge flange (24), and are integrally connected to one another via saddle bars (42), the side edge flanges (24A ) have a width (B44) sufficient for engaging the transport and gripping device plus a minimum width (B24) for a sufficiently secure sealing surface and the width (B42) of the saddle webs (42) corresponds to twice the dimension of a usually safe minimum sealing surface.

29. Row of shells according to claim 28, characterized in that the lateral edge flange (24A) of the outer shells (12A, 12B, 12C) has a width (BQ) in the range between 10 and 14 mm and the saddle webs (42) a width in the range between 8 and 12 mm.

30. A row of trays according to claim 29, characterized in that the rear edge flange (24B) of the trays (12A, 12B, 12C), viewed in the direction of transport, has an expanded width of a total of 14 to 18 mm and is centered with respect to the trays (12A, 12B) , 12C) is provided with a prefabricated handle recess (GM), which is used for the later formation of the

Gripping tab for detaching the film composite from the carrier material (26) is suitable.