EP1089912A2

EP1089912A2 - Airtight food packaging and a method, device and tray for the production thereof

Info

Publication number: EP1089912A2
Application number: EP99932726A
Authority: EP
Inventors: Jochen Dietrich; Kurt FCP Europa Carton Faltschachtel GmbH RÖMER; Hans Multivac Sepp Hagenmüller KG NATTERER
Original assignee: A&R Carton GmbH
Current assignee: PTS Consulting AG
Priority date: 1998-06-25
Filing date: 1999-06-24
Publication date: 2001-04-11
Anticipated expiration: 2019-06-24
Also published as: WO1999067143A2; ATE258883T1; EP1089912B1; DE19828381A1; WO1999067143A3; DE59908473D1; JP2002518262A; CA2353684A1

Abstract

The invention relates to an airtight, preferably oxygen-tight food packaging comprising a peripheral edge flange. The edge flange is lined with a plastic film, especially with a plastic composite film, which engages with the same inside. The inner space of the packaging is closed or sealed in an airtight, especially oxygen-tight manner over the edge flange by means of a covering film. In order to improve the producibility while ensuring a lasting air-tightness of the packaging, a shell part (40) is provided which at least partially forms the packaging base (41) and the side walls (43; 443). An uninterrupted collar which forms the edge flange (52) is placed on said shell part.

Description

description

Gastight food packaging and process. Device and trav for their manufacture

The invention relates to a food packaging according to the preamble of claim 1 and a method for producing such a packaging according to claim 13, a device for carrying out such a method according to the preamble of claim 19, a semifinished product or tray suitable therefor in the form of erected and glued trays according to claim 23 and a method for its production.

A large number of food packaging are on the market, with special efforts being made recently to keep the proportion of non-recyclable plastics in such packaging to a minimum. So far, food packaging in the form of deep-drawn plastic trays has prevailed, which are generally thermoformed from a carrier material which is formed, for example, from PVC, polyesterol or polyester.

In the case of the conventional shells made of PVC, polyester or polyesterol, a very uneven thickness distribution is produced on so-called "vacuum molding and filling systems" due to the production technology, due to the available starting thickness in the known thermoplastic molding process.

On the one hand, this requires a strong initial thickness of up to 1000 μm in relation to the desired drawing depth and container shape in order to achieve the required residual wall thicknesses in the base radii. On the other hand, the thinning leads to the formation of the plastic shells pulling plastic films in the base radii very often to so-called "kink breaks", which can occur especially during transport.

Series tests have also shown that the barrier layer layer used in the production of the plastic shells, preferably made of polyvinyl alcohol (EVOH), which ensures the necessary oxygen barrier and is embedded between the carrier film and the sealing layer in a previously described application of so-called rigid film composites, is a significantly poorer molding result shows, ie this EVOH layer also has small residual wall thicknesses.

It has therefore been found necessary that the plastic carrier material of the shells to be formed, which is required for the dimensional stability, is equipped with an additional oxygen barrier layer. This oxygen barrier layer usually consists of polyvinyl alcohol. In addition, a third film layer is required to be able to seal the lid film.

This requires a so-called multi-component, relatively thick multi-layer composite film, which makes recycling, ie reuse of the same type, impossible.

Such a shell is described for example in EP 0169799. It also discloses a method in which a large number of individual, separate trays are introduced into a filling or sealing station. The trays are successively lined with a thin plastic layer before they are filled with food and sent to a sealing station. In the sealing station, a cover sealed on the dishes filled with food. This creates a bowl, the base material of which is essentially ground wood or foamed plastic. The advantage of these packaging systems with such trays is that the packaging device can be clearly structured, and a modular arrangement of the device is also possible.

In contrast, attempts have been made to reduce the proportion of plastic in such food packaging, which must be relatively high in order to achieve the required residual wall thicknesses in the base radii, by using coated cardboard. Here, however, it has been found that it is difficult to process cardboard with coated plastic materials in devices in which largely known or already existing modules are used. In addition, the maximum mold depths for such containers pressed from coated cardboard are limited to 25 to 30 mm.

Even if such containers produced in the cold press process are largely made oxygen-tight by means of a barrier film sheeting, folds are formed due to the material displacement which has occurred as a result of the cold compression molding process. These folds extend into the edge flange area of the container, which makes a secure and uninterrupted, but above all oxygen-tight sealing with the cover film impossible. For example, to produce container depths of more than 30 mm depth, containers made of coated cardboard are used, which are formed from blanks. These made of coated cardboard on a separate unit are erected, folded and glued and fed to the packaging system as a container. However, it is not possible to connect such containers made of coated blanks at the cutting or gluing points in a gas and oxygen-tight manner. Such problems occur in particular in containers which have an edge flange. With the already known coating of cardboard blanks, only a certain level of moisture stability is achieved, and the moisture cannot also be completely shielded at the open cut edges.

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 form, fill and seal systems, the proportion of plastic being reduced to a minimum, but at the same time Stability of the container and the oxygen density can be kept at a particularly high level.

A further need is to develop a method for the oxygen-tight packaging of foods with the aid of a food packaging of the above type in such a way that conventional packaging systems can be operated with a higher cycle rate and even more economically. Finally, one is looking for a device for carrying out the above-mentioned method, which is characterized by a particularly low susceptibility to failure of the packaging systems even at the highest number of cycles.

In order to take these needs into account, the older patent application P 196 54 230, the content of which is expressly referred to here, describes a food packaging and a process for its production and a device for carrying out the method with a suitable semi-finished product or tray is proposed,.

The food packaging proposed there has a cardboard blank lined with a thin plastic composite film as a load-bearing base, which can be erected automatically and the interior of which is glued to the cut edges. The cardboard blank also has an edge flange with individual edge flange segments, to which the cover film is then attached. In addition, according to the invention, the edge flange is shaped on the outside in such a way that the edge flange segments are flush with one another in the sealing position. For this purpose, the individual edge flange segments have miter cut lines, on the basis of which the angular position of the edge flange can then be determined. By using prefabricated cardboard blanks, there is the advantage that no thinning of the material occurs when erecting the cardboard blanks, in contrast to the known tray. As a result, the disadvantages caused by the thinning of the material are overcome with the food packaging according to the invention. The fact that the edge flange segments are flush with one another in the sealing position results in a closed edge flange surface, which is then used to securely seal the cardboard blank.

In the case of such gas-tight or oxygen-tight packagings, however, particular care must be taken to ensure that the tightness produced by the sealing flanges is also guaranteed over a longer period of time. Otherwise, the food technology requirements can no longer be met. In the case of the packaging already proposed, the quality of the seal is determined by the accuracy of the blanks. In other words, the danger that ambient air will enter the Packaging via capillaries in the sealing flange can only be insulated by extremely high precision in the manufacture of the erected trays and in the positioning in the lining and sealing station. As a result, the working speed can be reduced excessively.

The invention is therefore based on the object of creating a food packaging of the type described above which is distinguished by the advantages described at the outset and additionally by the fact that it can be produced more quickly and reliably with permanent gas or oxygen tightness. Another object is to provide a method for producing such a food packaging that can be carried out according to a simple process. Finally, a device for carrying out the manufacturing process is to be created which is simple in construction and has the particular advantage that conventional packaging systems can be integrated as far as possible into the device. Finally, a semi-finished packaging product or a packaging tray is to be created which is particularly advantageously suitable for the packaging method according to the invention, the design having the advantage that large quantities per unit time can be produced with such high precision that the quality requirements of oxygen-tight packaging are ensured even with the greatest throughput of the packaging system.

This object is achieved with regard to food packaging with the features of patent claim 1. According to the invention, the packaging is equipped with an uninterrupted collar, which thus provides a continuous surface for sealing the packaging. The continuous, ie uninterrupted collar has parts already when attaching the plastic film lining the inside of the packaging, since the best conditions are formed for a large-area connection between the plastic film and the edge flange. In addition, there is the additional advantage that damage to the plastic film can be excluded even at higher operating speeds of the packaging machine. The decisive advantage is shown when sealing the packaging. This is because the uninterrupted surface of the edge flange, which is covered by the plastic film of the lining, offers optimal conditions for the largest possible sealing of the cover film. It has been shown that in this way the working speeds of the packaging machine can be increased considerably without running the risk of creating capillary-like radial channels between the cover film and the lining film, which would be detrimental to long-term sealing.

The design of the food packaging according to the invention does require a somewhat more complex structure of the packaging blank. It turns out, however, that the circumferential flange can be used in a particularly advantageous manner to stabilize the packaging trays, even if the connection between the tray components is only carried out selectively or in regions and not over the entire area.

A particularly advantageous further development results from the further development of patent claim 2. Because this design makes it possible to save weight in the area of the shell part, which has a positive effect on the DSD fees.

Basically, it is possible to design the continuous collar as a closed ring. With the development of claim 3, however, the particular advantage is achieved that there is less waste. In other words, cardboard mass can be used sensibly and effectively to stabilize the side walls of the shell part.

If the tabs of the edge flange are attached, preferably glued, to the inside of the side walls of the shell part, there is the particular advantage that the entire outside of the side walls is suitable for printing, i. H. can be used as information and advertising space.

The packaging according to the invention is particularly suitable for a semi-finished product made of cardboard.

According to claim 6, the plastic composite film has an oxygen barrier layer, preferably made of polyvinyl alcohol, a sealing layer, preferably made of peelable polyethylene, and an adhesive layer, preferably made of modified polyethylene, in particular a copolymer of ethylene with 6% methacrylic acid, which is partially (50%) containing Na - or zinc ions are neutralized (Surlyn A), a flexible composite is used, whose oxygen permeability can be determined in advance and is not changed even in the embedded state. Therefore, a significantly thinner EVOH layer, which is embedded in a flexible composite, can be used. The peelability of the plastic film results in excellent environmental compatibility. As has surprisingly been found, the plastic film can be kept extremely thin and still stabilize the tray, even if it consists of simple cardboard, in such a way that even relatively deep packaging can be produced with sufficient stability. If the food packaging according to the invention is preferably equipped with a cardboard blank which consists of a recyclable or preferably two-layer cardboard, then a food packaging is created which is suitable for bearing a special advertising effect on the outer layer of the cardboard blank. In particular, this creates a possibility of optically emphasizing the food packaging according to the invention.

The design according to claim 10 has the particular advantage that the surface structure of the tray is adapted to the specific requirements. For the lining of the shell, it is advantageous if the plastic film heated during the molding process forms an intimate connection with the surface of the shell part in a short time. In contrast, it is important for the outside of the shell part to create an appealing exterior and good prerequisites for the printing to be carried out as a rule. It has been shown that the second, i.e. H. inner layer can easily consist of recycled cardboard, which saves costs and achieves special advantages "with regard to environmental compatibility.

Through the choice according to the invention of the lined cardboard blanks, there is a container which is oxygen-tight except for one side, namely the upper side, when it enters the vacuuming or sealing station. In addition, since the plastic-lined cardboard blank also has a particularly high dimensional stability in the area of the edge flanges specially designed according to the invention, this edge flange can be securely accommodated between the seals of the closed sealing tool, so that according to the invention only the interior nenhohlraum of the molded carrier shell must be evacuated. The power consumption of the packaging system for generating the evacuation is reduced, the cycle number of the packaging system can be increased considerably as a result.

It has been shown that the edge flanges designed according to the invention achieve high stability and that there is no uncontrolled breakage even when the shell is filled with food. The operational reliability of the device can also be increased by supporting the edge flanges, which are located between the interior of the carrier shell and are designed as sealing webs, from below by means of slide and guide rails oriented parallel to the direction of transport. Also advantageous is the further development that the containers are supported in the filling section from below by means of a support belt running synchronously with the transport device.

The fact that the erected cardboard blanks according to the invention are arranged in rows in the forming station, enables a widened sealing surface to be formed on the edge flanges between adjacent cardboard blanks. This ensures that the seal is achieved safely. It is also achieved that several cardboard blanks can be produced at the same time, and the sealing is simplified by the widened sealing surface due to the adjacent edge flanges.

With these developments, there are particular advantages of largely simplifying a packaging system, since this method no longer requires a separate deep-drawing stamp station or special preheating system. Nevertheless, the required flow path can be used according to the invention for accommodating the filling station and thereby creating a space-saving design of such a packaging system.

Either the system as a whole can be considerably shorter or, if necessary, the filling section can be used much better, which makes the filling process easier.

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

Finally, the power consumption of the packaging system, particularly in the area of the forming station, is considerably reduced, since the time required to warm a conventional hard film of approx. 500 to 1000 μm (PVC, polyester or polyester) can be significantly reduced. The required inherent stability of the containers is achieved according to the invention by using the cardboard blank described, in particular if the cover film is attached to the plastic film lining the cardboard blank.

The food packaging according to the invention has increased dimensional stability compared to food packaging also using cardboard blanks and is to a high degree stable against twisting.

An advantageous further development of the manufacturing method results from the further development of patent claim 15. By attaching the plastic film to the edge flanges of the trays, the latter can be reliable and can be transferred to the packaging system with very precise timing. This has the additional advantage that the module of the packaging system which has the filling system can be kept largely unchanged, while a preceding module for feeding the trays can be positioned in the system in a particularly space-saving manner, namely with an overlap of one cycle feed length.

The development of the method according to claim 17 not only leads to an extremely high throughput rate, but it has the advantage in particular in connection with the design of the shell part according to the invention that the vacuum can be used extremely effectively to remove the film from the lining in the shortest possible time to pull into the interior of the shell part. This is because the continuous collar according to the invention, which forms the edge flange, allows the shell part to be cut so that the side walls are separated by a slot due to the erected state of the shell part.

Advantageous embodiments of the device for carrying out the method are the subject of claims 19 to 25. The tray belonging to the food packaging according to the invention is the subject of claims 23 to 29. The tray can be provided with almost any shape, the particular advantages then being achievable when the shell part exceeds a certain minimum depth. The floor preferably has a polygon shape.

With the method for producing the tray according to claim 30, it is possible to join the two parts of the tray in a very short time and with the greatest possible accuracy, the advantage being achieved that the manufacturer development of the trays remains independent of the working speed of the packaging system. The trays are preferably nested and placed in a magazine for cardboard trays and from there individually on a carrier belt of the transfer module of the packaging machine.

Further advantageous refinements 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

Figure 1 is a schematic side view of a first embodiment of the packaging system according to the invention.

2 shows an exploded view of a first embodiment of a carton tray for use in the production of a packaging according to the invention;

3 shows a plan view of a cardboard blank for the collar of the packaging according to FIG. 2;

4 shows a plan view of the blank according to FIG. 3 with angled tabs ready for assembly;

5 shows a plan view of the associated cardboard blank for the shell part;

FIG. 6 shows a top view of the blank according to FIG. 5 in an upright form; FIG.

Fig. 7 is a perspective view of a series of erected carton blanks. Fig. 8 in side view on an enlarged scale the molding station of the packaging system.

Fig. 9 is a front view of the molding station shown in Fig. 8 with the inserted cardboard blank arranged in rows one after the other and the plastic composite film which is fed for the lining;

10 is a perspective view of cardboard blanks arranged laterally in a row, which are already lined with the plastic composite film, the heat-laminated edge flange region being shown in a sectional view according to FIG. 10A along the line of the cardboard blanks arranged in a row on an enlarged scale .;

11 is a front view of the vacuum or sealing station with inserted cardboard blanks which are already lined with plastic composite film and are thus connected to form a row;

12 shows a perspective view of the connected cardboard blanks with plastic composite film and sealed cover film, the details of the cardboard blank and the adhering layers being shown more clearly in FIG. 12A on an enlarged scale;

13 shows a perspective view of a packaging which is ready for use or consumption according to the invention;

14 shows a perspective view of the shell according to the invention with the cover film partially detached;

15 is a perspective view of the shell according to the invention with the cover film partially detached and the inner film partially detached; 16 shows a schematic representation of a section of the production plant for the cardboard trays;

FIG. 17 is an exploded view of a modification of the tray corresponding to FIG. 2; and

18 is a view similar to FIG. 1 of the packaging machine, in which the trays according to FIG. 17 are processed.

1 shows the side view of the packaging system, which essentially has five main stations, namely a stapling station HS for attaching a lining film 134 for prefabricated trays, a forming station (FS) in which the plastic film is molded into the trays, a filling section (BS), a sealing and vacuuming station (VS) and a preferably two-stage separating system 181, 182, the latter also being designed in one stage.

The transport of the carton blanks or trays 110 arranged in a precisely fitting row to the individual stations takes place. preferably via a transport chain 148 or, when used on a so-called "tray sealer", via a specially designed conveyor belt with receiving spaces for the adjacent cardboard blanks.

To relieve the transport chain 148 in sections, support belts (not shown in more detail) can additionally be provided below the transport chain 148.

The one with ^' ! _ designated module of the actual packaging machine, which is largely designed as a commercially available machine and only redesigned in some areas there may be a further module II upstream, via which the trays 110 received in a magazine or dispenser 112 are separated and transferred to module I.

In detail, the prefabricated carton blanks 110 - preferably in rows with 2 to 5 trays next to one another - are clock-controlled placed with the aid of a preferably pneumatically operating separating device W9 on a compartment belt 112, with which at least one clock-controlled the at least one carton blanks into a transfer station US is transported. There, the at least one tray 110 is also lift-controlled in a clock-controlled manner by means of an excavation station 114 by means of a special transport stamp 113 vertically up to the plane EKF of the plastic film 134 and into the area of the stapling station HS, in which the lining film is preferably point-wise raised by means of a heated stamp 118 the leading and / or trailing areas of the edge flange of the trays is tacked. In the case of a tray sealer system, the cardboard blanks are placed in corresponding receiving spaces in the transport chain 148.

With this design, it is possible to arrange the module II in a very space-saving manner and to save the overlap area ÜB in the direction of transport.

Starting from this stapling station, in which the pre-fabricated trays arranged in rows and close to one another are located on the plastic film and entering the molding station FS, the actual molding or lining process of the trays 110 begins by means of the plastic, preferably the plastic, composite film 134. In the molding station, the lining of the inner surface is arranged in rows Cardboard trays 110 are carried out with an oxygen-blocking plastic composite film 134.

The plastic composite film 134 is drawn from an endless roll 133, which is fastened on a support arm above the inlet section of the packaging system, via deflection rolls (not specified in any more detail) via the trays 110 arranged in rows in the receiving molds, essentially parallel to the transport chain 148.

When a tray sealer is used, the transport chain 148 guides the trays 110 arranged in rows in the receiving spaces of the transport chain under a molding station FS, the working principle of which is to line the inner surface of the trays 110 with the plastic composite film 134 on a molding, filling, and sealing system corresponds to the Iso-Pack system from MULTIVAC.

Thereafter, the trays 110 are conveyed by means of the transport chain 148 into the area of a filling section BS, which is also designed in such a way that they permit a row-by-row filling.

To relieve the load on the transport chain 148, the trays 110, which are now connected by the plastic composite film 134, can be supported by a support belt which works in sync with the transport chain.

The filled trays run from the filling section BS into a vacuuming and sealing station VS, wherein at the same time a cover film 120 guided by an endless roller 122 via a deflection roller system is guided into the vacuuming and sealing station VS substantially parallel to the transport route. The operation of the vacuum and sealing station tion VS corresponds to conventional systems, for example from Multivac, and is described in detail in FIG. 12.

After the filled packaging containers have been sealed, they are again conveyed to the singling stations 181, 182 by means of the transport chain, the trays 110 arranged in a row in a row being able to be supported again by a conveyor belt 150 which operates in the same cycle.

As can also be seen in FIG. 1, the transport path of the transport chain 148 and the support belt 150 extends from the donor to immediately behind the two-stage singling station 181, 182, so that the entire system operates in synchronism.

The special feature of the packaging device is that on the one hand a specially designed tray 110 is used and on the other hand this tray 110 is manufactured in a special way and is supplied to the packaging system as a semi-finished product.

Contrary to conventional designs of such packaging systems, the dispenser 112 feeds a tray 10 which has already been preformed and is dimensionally stable, for example, by adhesive bonding, with an upper edge flange 52. The semi-finished products or trays 10 fed to the packaging device - as shown in an exploded view in FIG. 2 - have edge flanges 52 which are particularly designed according to the invention and which are formed by a continuous collar which is placed on a shell part 40.

FIG. 2 shows the two components of the tray 10 in the preformed state, immediately before the parts are assembled and connected to one another, preferably be stuck. In Figures 3 to 5, the parts are shown in plan view in detail.

Both parts are designed as a cardboard blank, preferably a two- or multi-layer cardboard is used, so that the outside of the tray can have a different quality than the inside. The cut of the collar forming the edge flange 52 has, as shown in FIG. 3, incisions for the formation of trapezoidal tabs 51 which hang on the edge flange via predetermined bending lines.

The shell part 40 has a cut according to FIGS. 5 and 6. The side wall sections 43 hang on a bottom part 41 via fold lines 42, which touch in the erected state (FIG. 6 and FIG. 2).

Because the angled tabs 51 are connected, preferably glued, to the side walls 43 in the state in which they are placed on the shell part 40, the latter are stabilized by the edge flange 52, so that the tray has high torsional rigidity with little use of material - low cardboard weight.

The adhesive connection is preferably point-shaped or line-shaped, as indicated by the hatched areas 47 in FIG. 2.

The tabs 51 are fastened to the inside of the side walls 43 so that the outside of the side walls remains continuous, which is conducive to printing.

The height H43 of the walls 43 is greater than the height H51 of the tabs 51, ie the tabs only overlap the side walls to a fraction of the area, which saves weight and thus DSD fees. In Fig. 7 erected, rows of cardboard blanks 10 are shown in perspective, wherein a possibly provided recessed grip GM can also be seen, which can be provided on an edge segment of the edge flange 52.

In the side view according to FIG. 8 it can be seen in which way in the forming station FS the tool halves 116 and 118 interact with the trays lying one behind the other and by means of a heating device 172 line the inside or surfaces of the trays 10 lying one behind the other with the plastic composite film 134.

The tool of the forming station FS, which works according to the so-called skin process, consists of a lower mold 116 and an upper mold 118, which are moved apart and moved together in a clocked manner according to the arrow shown in FIG. 8. In this case, the lower mold 116 preferably has a profile for positively receiving the cardboard blanks 10, so that the edge flanges 52 of the cardboard blanks 10 are supported in a sealed manner. The upper mold 118 is also designed so that a heating device 172 can be accommodated. With 173 and 173A, recesses in the upper and lower part 116, 118 are shown, which are designed in accordance with the recessed grips GM.

4, the front view of the molding station FS is shown. It can be seen that the lower mold 116 has web-like inserts 166, the shape of which is adapted to the cross section of the trays 10 arranged in rows. Here, the closely spaced edge flanges of adjacent trays 10 lie on these inserts, which are designed in the form of webs, so that they fit exactly, so that when they are moved together of the tool halves 116 and 118, the individual trays are additionally positively supported by the mold inserts 158 provided, the surface contours of which correspond precisely to the shape of the trays. The functionality of the forming station FS, in particular the skin process, is briefly described below:

If a row of erected cardboard blanks, which lie with their edge flanges in a row close to one another and thus form a saddle-shaped support, is introduced into the forming station FS via the attached plastic film 134 (stitching points), the lower tool part 116 of the forming station, which was previously extended downward, moves FS in the direction of the arrow. When the lower tool part 116 moves together against the upper tool part 118, an almost complete vacuum is created in the upper tool part 118. The plastic composite film 134 lying over the cardboard blanks 10, which are arranged closely in rows, is thereby applied to the entire surface of the heating plate 172 and heated.

After the specified heating time has elapsed, the upper tool part 118 is ventilated while the lower tool part 116 is evacuated. This change creates a differential pressure of approx. 1 bar, which causes full-surface heat lamination between the plastic composite film and the inside of the tray (see dashed line 134A). Since line-shaped openings remain between the side wall sections 43 due to the design of the shell part 40, the drawing in of the film can even be promoted.

At the same time, the continuous edge flanges 52 are heat-laminated over the entire surface. Since the inner surfaces of the closely spaced carton blanks are now lined with the plastic composite films, the forming station FS is opened at the same time, which means that the trays connected by the plastic composite film are released and conveyed to the transport chain 148 for filling.

FIG. 10 shows the row of trays formed by the closely spaced trays 10 and lined with plastic composite film 134 on the inside, as it leaves the molding station FS. As can also be seen, the plastic composite film 134 also covers the grip hole recess GM in the edge flange.

FIG. 10A (section along the edge flange 52 of a tray 10 with the composite film 134 lying thereon) shows the individual layers forming the composite film. The plastic composite film 134 has an oxygen barrier layer 136, preferably made of polyvinyl alcohol (EVOH) and a sealing layer 138, preferably made of peelable polyethylene, and an adhesive layer 137, preferably made of modified polyethylene. It has been shown that the error coating of the carrier material forming the food packaging can be carried out extremely thinly. The film thickness is preferably in the range of the residual wall thicknesses in the base radii between 25 and 30 μm.

By selecting a suitable surface structure of the cardboard on the inside of the tray 10, the interlocking of the film 134 with the cardboard can still be optimized.

The plastic composite film 134 can also be constructed and controlled in its behavior that it can be detached from the cardboard carrier after use of the packaging, so that pure components are available for disposal or recycling. According to the invention, the finger hole recess GM also serves this purpose.

After leaving the forming station FS, the connected trays 10 pass through the filling station along the filling section BS, during which they are filled with the food to be packaged. The transport of the coherent trays 10 takes place at intervals, as it were, through the joint installation. The filled trays 10 run from the filling section BS into the vacuuming and sealing station VS, in which they are received by the lower part 116 by means of appropriate mold inserts (see FIG. 11). Such a vacuum or sealing station of the conventional type consists of a lower part 216 and an upper part 218, which are moved together and moved apart in a clocked manner. The lower mold 216 preferably has a profile for the complete reception of the trays 10 designed according to the invention in such a way that the edge flanges of the shells can be supported in a sealed manner. The upper part is designed in such a way that it can receive a heating plate 274 which has a line pattern and is movable in the vertical direction.

The line pattern is designed in such a way that it defines surface areas at which the carton blank edge flange is to be sealed with the cover film 120.

12 is intended to show the function of such a vacuuming or sealing tool when used according to the invention. Known and proven conventional systems with minor changes can also be used for this process. 12 shows the lower mold 216 with the web-like inserts 266, the shape of which is adapted to a cross section of the saddle strip forming between two adjacent edge flanges of the trays 10, so that when the tool halves 216 and 218 are moved together, the contiguous trays 10 by the intended mold insert 258, the Surface contour corresponds to the shape of the tray lying thereon, are positively supported. Seals are designated by 270, against which the edge flange or the saddle webs of the connected trays 10 lie when the tool 216 and 218 are in the closed state, so that the individual cardboard blanks which already contain the food in this state can be vacuumed .

With 274 heating devices are referred to, which are accommodated in accordance with a pattern aligned with the edge webs in the upper tool half 218, so that when the tool halves 216 and 218 are moved together, the cover film 120 is welded to the relevant edge flanges of the individual containers in such a way that a circumferential continuous Sealing surface comes about.

Due to the special design of the continuous edge flange 52, the seal is free of capillary channels via which a gas exchange with the surroundings could take place.

At this point it should be emphasized that a commercially available vacuum station can be used, in which, after evacuation, gassing, for example with the usual gas mixture 2 / CO2, can usually be used in a ratio of 70:30. The heating plate 274 located in the upper part - of the tool 218 is preferably provided with sealing webs shaped in relief. formed by the action of heat and pressure, the cover film is sealed with the sealing coating of the peripheral edge flange and the resulting saddle webs of the connected trays.

FIG. 12 shows how the trays 10 filled, sealed and connected with food have now left the vacuuming and sealing station.

As can be seen by the selected hatching, the entire plastic composite film 134 is welded to the cover film 120 at the sealing surfaces provided. Only in the area of the recessed grip designated GM in the rear edge flange area (seen in the direction of travel) is the sealing with the plastic composite film 134 with the cover film 120 prevented by a special configuration of the sealing tool. Using the punched-out hole in the rear edge flange GM and the cover film 120 not sealed at this point with the plastic composite film 134, this enables the film cover to be removed later or the plastic composite film to be removed from the tray -10.

After leaving the vacuuming and sealing station VS, the filled trays connected via the cover film and plastic composite film 134 are fed to a separating system 181, 182 which is preferably designed in two stages.

It is also possible to use complete punching and separation of the individual food packaging. In the case of a complete punching, the second stage of separation is therefore omitted. After leaving the separation The individual trays are present at the station as shown in FIG.

With the above food packaging, depending on the desired shape, an average of about 20 g of plastic that can no longer be used can be saved per food packaging, i.e. approx. 70% of what occurs with conventional packaging of this type.

The working width of the device is of course not limited. However, it has been shown that the widths should be at least about 420 mm in order to keep the economy of the device at a particularly high level.

The cover film 120 is preferably likewise produced from a plastic composite film 134 which contains an oxygen barrier layer which is covered on the side facing the cardboard blank by a peelable plastic layer, preferably made of modified polyethylene. This layer then forms the sealing seams with the plastic composite film 134 via sealing webs of the edge flanges.

The film layer facing the heating or sealing element 272 is preferably formed from a film quality with a particularly high melting point or a heat-blocking layer, which preferably contains polyethylene and which lies above the oxygen barrier layer, in order to ensure sufficient shape and surface stability when sealing with the lower mold part To ensure the sealing process. Since the sealing layers of both the cardboard blank surface and the cover film 120 are preferably 'peelable' to one another, a firm result is created when these two sealing layers are sealed Connection that can be peeled off by hand as far as possible without destroying the corton cutting film 34 (see FIG. 14).

Of course, deviating from the previously described exemplary embodiments are possible without departing from the basic idea of the invention. So it goes without saying that you can vary the number of trays lined up per row or cycle.

It is also conceivable that the tray rows are made sterile or sterile after leaving the forming station FS using a special device. This is advantageously a so-called "hydrogen peroxide shower".

On account of the method according to the invention used both in the case of the oxygen-tight plastic composite film and in the case of the oxygen-tight cover film 120, a composite combination of films from the polyolefin group can be used. This composite combination can be recycled as a monofilm. It has been shown that this regranulate can be used as a filling material in the field of PE heavy film production.

Due to the interior coating made by means of the plastic composite film, the stability of the tray is considerably improved, particularly via the edge flanges designed according to the invention. After solidification, the plastic composite film 134 loses considerable flexibility and additionally stiffens the entire tray over the edge flanges.

The subsequent sealing with the lid foil over the peripheral edge flanges gives the cardboard cut an additional torsional stiffness or dimensional stability.

An extremely secure sealing with the trays lined with barrier layer composite film by the barrier layer cover film is achieved according to the invention in that, due to the process, the peripheral edge flanges form close to one another, so-called saddle webs with a sealing surface, which is increased to twice that of conventional edge flanges.

Since the complete sealing surface available, which is heat-laminated with the sealing side of the barrier plastic composite film 134, is available as a sealing surface with the cover film 120, the individualization of the packs, which is only carried out after the sealing, ensures that there is always a sufficiently wide area to form a secure sealing seam maintained.

In the case of individually fed trays which do not have this particular design of the edge flange according to the invention, due to tolerances when fixing the trays in the process process or due to the production-related fluctuations. a uniformly wide and thus sufficient secure sealing surface cannot be achieved in the carton blank design. The separation of the oxygen-tight film inner component from the actual stabilizing cardboard blank is a further essential point of the invention (see FIG. 14). The plastic composite film lining the inside of the tray is heat-bonded to the fibers of the inner walls and the bottom of the cardboard blank.

Using known processes, for example the Multivac Skin System, in which the heated, thus plasticized plastic composite film with the specially designed The lamination layer, which preferably contains a Surlyn blend from Dupont or a blend (PE type) with a particularly high (preferably over 20%) ethylene vinyl acetate content, the plasticized composite film is made by the corresponding pressure difference pressed against the inner surfaces of the tray and can penetrate the fibers of this inner surface.

After evacuation or gassing in the sealing station, the cover film 120 is firmly connected to the lower part of the packs via the circumferential edge flanges and the saddle webs of the trays connected in rows, which are coated with a sealing layer as described in the method.

The intended semi-oval punching (GM) of the rear edge flange lying in the transport direction and the corresponding configuration of the sealing tool in this area creates the possibility of a so-called grip tab, which is formed from the cover foil which is not sealed at this point with the cladding foil, on the recessed grip hole GM to remove the entire composite from the then pure cardboard blank, which can then be mixed according to type.

The field of application of food packaging also includes peeling off the lidding film from the sealing webs to open the package, so that contents can be removed easily and without tools. This can be done by a special design of the sealing tool in the sealing station without major changeover work.

In this case, the consumer loosens the lid film from the sealing surfaces until he can easily remove the contents (see Fig. 15). The plastic composite film and the not completely peeled off lid film then detached from the actual cardboard blank on the grip hole provided via the grip tab. This ensures that the separation is sorted and that the individual materials can be recycled.

FIG. 16 shows a schematic view of a tool for manufacturing the trays 10. The cardboard blank 40 is erected in a base mold 316 and stabilized with a precise fit by means of an air suction device 319. Aligned above the bottom shape is the upper shape 318, which carries the erected collar with edge flange 52.

The molds 316, 318 are brought together after a cold or hot glue has been applied to one of the overlapping surfaces of side walls and / or tabs. If hot glue is used, the setting time can be controlled more precisely and the cycle frequency during production can be increased further. The areas to which the adhesive is applied are indicated in different shapes in FIG. 16, which is intended to express that there is a variety of design variations depending on the load profile of the trays.

Of course, deviations from the variants shown are possible without departing from the basic idea of the invention. Figure 17 shows a somewhat modified design of the tray. The collar 452 is designed without tabs and is placed exactly over the angled edge flange segments 444 of the side walls 443 of the shell part 440 and is thus firmly connected, preferably glued. "X" denotes those areas at which adjacent wall areas 443 are connected to one another by overlapping tabs 443 A. With this tray, a modification of the packaging system according to FIG. 18 can be useful. Erected or prefabricated trays 510 are removed in rows from a magazine 512 and transferred to a clocked conveyor belt 511. The trays 510 are then transported under a stamping device with a stamp 517, in which the edge flange formed by the segments 444 is broken before the collar 452 is placed in the gluing station KS, in such a way that the surface which is as flat as possible for the placement of the collar arises with sections 444 which are as flush as possible. The stamp 517 is designed in such a way that the edge flange 552 is broken into the sealing position which is possible at the ends of the edge flange segments 444, depending on the fermentation cut, with a corresponding inclination. The transfer station US (see FIG. 1) connects to the gluing station.

If a method according to the known tray sealer is used, the transport chain 148 then transports the trays 10 arranged closely to one another in a cycle-controlled manner into the forming station FS. The molding station FS can be configured in the same way as, for example, a station of a molding, filling and closing system according to the Multivac CD6000, which works according to the skin system.

The invention thus creates a food packaging in the form of a dimensionally stable carton blank with an edge flange running around the top, which according to the invention is continuous and is placed on the shell part. In this way, the sealing surface along the flange gets a special quality that ensures tightness in the long term.

The carrier shell consists of cardboard and carries on the inside in the area of the rim flanges Fold an oxygen-saving plastic film that is suitable for sealing with the lid film.

A method is also described, a device for producing an oxygen-tight food packaging, wherein preformed and dimensionally stable trays are supplied by a dispenser system or, in the case of use, via a so-called tray sealer, i.e. from the donor directly into the receptacles in the transport chain of a tray sealer. These trays are lined in a molding station with a plastic composite film, which preferably contains an oxygen barrier layer.

Claims

Expectations

1. Food packaging with a peripheral edge flange, which is lined on the inside with a plastic film, in particular a plastic composite film that grips the edge flange, and whose interior is sealed or sealed gas-tight, in particular oxygen-tight, via the edge flange, characterized by a packaging base (41 ) and the side walls (43; 443) at least partially forming shell part (40) and an uninterrupted collar placed on this, forming the edge flange (52).

2. Food packaging according to claim 1, characterized in that the edge flange (52) stabilizes the side walls (43).

3. Food packaging according to claim 2, characterized in that the edge flange has tabs (51) which are attached to the side walls (43) of the shell part (40).

4. Food packaging according to claim 3, characterized in that the tabs (51) on the inside of the

Side walls (43) are attached.

5. Food packaging according to one of claims 1 to 4, characterized in that the shell part (40) and / or the collar (52) is formed by a cardboard blank.

6. Food packaging according to one of claims 1 to 5, characterized in that the plastic composite film (134) has an oxygen barrier layer (136) preferably made of polyvinyl alcohol and a sealing layer (138) preferably made of peelable polyethylene and an adhesive layer (137), 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).

7. Food packaging according to one of claims 1 to 6, characterized in that the cover film (120) is formed by a plastic composite film (134) which, on the side facing the tray (10), preferably a peelable plastic layer, preferably made of polyethylene and at least overlying it has an oxygen barrier layer, preferably made of polyvinyl alcohol and a covering heat barrier layer, for example made of polypropylene.

8. Food packaging according to one of claims 1 to 7, characterized in that the plastic film has an initial thickness in the range between 100 and 150 microns depending on the depth of the mold.

9. Food packaging according to one of claims 1 to 8, characterized in that the shell part (40) and / or the collar (52) consists of a recyclable, preferably multi-layer cardboard.

10. Food packaging according to one of claims 1 to 9, characterized in that the carton has a cover layer facing the outside of the packaging with a first surface structure, e.g. is suitable as an information carrier layer and has an inside second layer with a specific surface structure.

11. Food pack according to claim 10, characterized in that the second layer preferably consists of recycled cardboard.

12. Food pack according to one of claims 3 to 11, characterized in that the tabs (51) are glued to the side walls (43).

13. A method for gas-tight or oxygen-tight packaging of food in a food packaging according to one of claims 1 to 12, in which the trays consisting of the shell part and the edge flange intermittently pass through a shaping station (FS) and a filling section (BS) which Vacuuming and sealing station (VS) is connected downstream, the trays () being arranged in rows in the forming station (FS).

14. The method according to claim 13, characterized in that the trays (10) of the molding station (FS) are supplied in the prefabricated state.

15. The method according to claim 13 or 14, characterized in that the lining of the inner surface of the carrier shells preferably in rows and by means of a plastic composite film (134) covering the entire sealing surface of the edge flanges (52), which takes place in one of the forming station (FS) - upstream transfer station (US) is tacked to the edge flanges () of the trays () (tacking points).

16. The method according to claim 15, characterized in that the _^ Tranεport of the trays is carried out (10) through the following stations by means of which the liner forming Kunεt- material film (134) randεeitig of grippers of a Tranεporteinrichtung, vorzugεweiεe Tranεport- a chain (148 ) is detected.

17. The method according to any one of claims 13 to 16, characterized in that the plastic composite film (134) if necessary after heating by forming a pressure difference in the trays (10) and firmly heat-laminated with the relevant edge flange and the inside of the associated trays (10).

18. The method according to any one of claims 13 to 17, characterized in that through the lining plastic composite film (134) coherent carrier shells in the vacuuming and sealing station (VS) with a cover film (120) are preferably welded continuously over the rim flange.

19. Device for performing the method according to one of claims 13 to 18, characterized in that the molding station (FS), the filling section (BS) and the sealing station (VS) are combined to form a first module (I), the one a second Module (II) forming supply unit for the prefabricated trays (10) is connected upstream, the two modules (I and II) overlapping in the transport direction of the trays (10).

20. Apparatus according to claim 19, characterized in that the first module (I) has a stitching station (HS) upstream of the forming station (), under which a transfer station (ÜΞ) for the trays (10) of the second module ( II) lies.

21. The apparatus according to 20, characterized in that the transfer station (US) has a vertically movable lifting device supporting the edge flanges () and the stapling station (HS) has vertically oppositely movable stapling bodies (118) with which the running between them Plastic film (134) forming lining () is attached to the edge flanges (52).

22. The apparatus according to claim 21, characterized in that the stitching body (118) are heatable.

23. Tray for a packaging according to one of claims 1 to 17, characterized by a shell part (40) at least partially forming the packaging base and the side walls and an uninterrupted collar () placed thereon and forming the edge flange (52).

24. Tray according to claim 23, characterized in that the edge flange (52) stabilizes the side walls (43).

25. Tray according to claim 24, characterized in that the edge flange has tabs (51) which are attached to the side walls (43) of the shell part (40).

26. Tray according to claim 25, characterized in that the tabs (51) on the inside () of the side walls (43) are attached.

27. Tray according to one of claims 23 to 26, characterized in that the shell part (40) is a cardboard blank.

28. Tray according to one of claims 23 to 27, characterized in that the side walls (43) taper downwards.

29. Tray according to one of claims 23 to 29, characterized in that the bottom (41) has a polygon shape.

30. A method for producing a tray according to one of claims 23 to 29, characterized in that the cut of the shell part is first erected in a first shape (315), and that the collar (52) is then positioned by means of a second shape (318) - nau placed on the shell part (40) and connected to it via selected areas, preferably glued.

31. The method according to claim 30, characterized in that the connection is made by means of a cold adhesive.

32. The method according to claim 30, characterized in that the bonding is carried out by means of a hot glue.