EP0946391B1 - Method for producing an oxygen-tight packaging, apparatus for carrying out said method - Google Patents

Abstract

Disclosed is a food packaging in the form of a shape-retaining preformed carrier shell comprising an upper peripheral edge (52), with a preferably oxygen-tight covering foil (20) to hermetically seal the inner space of the container. The edge (52) comprises individual edge segments (54) to fix the covering foil (24), wherein the edge (52) is formed on the outer side in such a way that the edge segments (54) evenly close each other in a closed position. Further disclosed is a method and a device for the production of oxygen-tight packaging, wherein preformed and shape-retaining carrier shells are fed by a dispenser. Said shells are covered with a plastic compound foil in a forming station. In order to enhance stability, the cardboard cuts (10) in the carrier shell rows are interconnected by connecting pieces that coincide with the edge (52) of the container thereby forming one piece. The shells pass through the food packaging installations in rows and synchronically and are sealed together.

Description

The invention relates to a method for the production of a food packaging according to claim 1 and an apparatus for performing such Method according to the preamble of claim 13.

Food packaging is in great variety on the market, with more recent efforts the share of not being undertaken recyclable plastics in such packaging to a minimum. Here have so far Food packaging in the form of thermoformed Plastic trays, which are generally enforced be thermoformed from a carrier material, which for example made of PVC, polyesterol or polyester becomes.

The conventional ones made of PVC, polyester or polyesterol Manufactured shells are produced in terms of production technology due to so-called "vacuum forming and filling systems" a very uneven thickness distribution due to the available output strength in the known thermoplastic molding process.

On the one hand, this requires in relation to the desired one Draw depth and container shape a strong starting thickness up to 1000 µm to the required residual wall thickness to reach in the bottom radii. On the other hand, it leads Thinning for the formation of the plastic shells plastic films to be used in the bottom radii very often to so-called "kink breaks" which, above all can occur during transport.

Series tests have also shown that the at barrier layer layer used in the manufacture of the plastic shells, preferably made of polyvinyl alcohol (EVOH), which ensures the required oxygen barrier and with a previously described application of so-called Rigid films connected between the carrier film and the sealing layer is embedded, an essential shows poorer molding result, i.e. low residual wall thickness also has this EVOH layer.

It is therefore necessary that the plastic carrier material of the shells to be formed, that for the dimensional stability is needed, with an additional Oxygen barrier layer is equipped. This The oxygen barrier layer usually consists of Polyvinyl alcohol. In addition there is a third layer of film required to seal the lidding film to be able to manufacture.

This requires a so-called multi-component existing, relatively thick multi-layer composite film, which is recycling, i.e. reuse, to make impossible.

Such a shell is for example in the EP 0196799. It also contains a procedure discloses a variety of individual, separate Trays in a filling or sealing station be introduced. The bowls become successive lined with a thin layer of plastic, before being filled with food and a sealing station are fed. In the sealing station a cover film is placed on the dishes filled with food sealed. This creates a bowl, the support material essentially wood sanding or foamed Plastic is. Furthermore, the bowl itself in be substantially porous so that the plastic film for Lining the shell due to a below the Shell generated vacuum can be applied. The Advantage of these packaging systems with such trays is that the packaging device is clear can be built, including a modular Compilation of the device is possible.

In contrast, attempts have been made to determine the plastic content in such food packaging, the order of the required residual wall thicknesses in the base radii reach, must be relatively high, thereby reduce that coated cardboard is used. A such packaging is described in document DE 4130905 A1. Here, however, it turned out that it is difficult, cardboard with coated plastic materials to process in devices in which largely known or existing modules used become. In addition, those made of coated Carton pressed containers the maximum Mold depths limited to 25 to 30 mm.

Even if through a barrier film sheeting such containers manufactured in the cold pressing process are largely equipped so that they are oxygen-tight unfolds due to the cold compression molding process due to the resulting material displacement. These folds extend into the edge flange area the container into it, ensuring a safe and uninterrupted, but above all, oxygen-tight sealing with the cover film becomes impossible. For example To produce container depths of more than 30 mm mold depth, become containers made of coated cardboard used, which are formed from blanks. This out coated cardboard on a separate unit are erected, folded and glued and used as containers fed to the packaging system.

However, it is not possible to use coated ones Cut the manufactured container to the cut or Adhesives are really gas and oxygen tight connect. Such problems occur in particular Containers that have an edge flange. In the already known coating of cardboard blanks only a certain moisture stability is achieved, with the open cut edges Moisture cannot be completely shielded.

From documents US 5,253,801 and US 4,200,481 one package is known in which a erected cardboard blank with a Plastic film is lined. It is in a cardboard blank before lining like this erected that edge flange segments together nudge. While packing according to US 4,200,481 the lining of the packaging with square floor plan is not complete, are in the packaging according to the 5,253,801 between the wall sections fold areas available that folded over when erecting the cardboard blank and must be placed on top of each other before the Lined with plastic film.

In the method known from US 4,200,481 for the production of a food packaging, the forms the preamble of claim 1, are erected cardboard blanks from one Donors in cycles, but occasionally one Forming station fed to a packaging system. The The packaging geometry is such that two mutually parallel edge flange segments Edge flange segments of the intermediate Border the wall segments so that a butt joint along parallel butt lines

There is a need for food packaging of the type described above produce that the packaging can be easily converted to conventional horizontal form, fill and seal system to produce, the share of Plastic is reduced to a minimum, at the same time however, the stability of the container and the oxygen density kept at a particularly high level can be.

In detail, the task is a process for the oxygen-tight packaging of food under With the help of a food packaging of the above Kind in such a way that conventional modular packaging systems with a higher cycle rate and can be operated even more economically. Another object of the invention is still to be seen in the device for performing the above mentioned method of the first packaging according to the invention to adapt so that the packaging systems are susceptible to faults minimized even with the highest number of cycles is.

These tasks are regarding of the method with the features of the claim 1 and with regard to the device for implementation of the procedure solved with the features of claim 13.

Because the erected cardboard blanks according to the invention in rows in the Forming station are arranged, it is possible that a widened one between adjacent cardboard blanks Sealing surface is formed on the edge flanges. Way the edge flange segments before insertion be burned into the forming station they can be flush with each other auliegen.

This ensures that the seal is achieved safely becomes. It is also achieved that several cardboard blanks can be produced simultaneously, and through the widened sealing surface due to the neighboring arranged edge flanges the seal is simplified.

The method results in particular Advantages of largely simplifying one Packaging system, since no separate Deep drawing stamp station or special preheating system are more needed. Nevertheless, the required throughput distance according to the invention can be used to accommodate the filling station and thereby a space-saving version of such Packing system can be created.

The overall system can either be considerably shorter or the filling section can, if necessary, be used much better, which in some cases the filling process is visibly easier.

The process has particular advantages if one Packaging structure is selected according to claims 8 to 12. Then the packaging which per se is not the subject of the invention as supporting base with a thin plastic composite film lined cardboard blank that automatically erectable and its interior to the Cut edges is glued. The cardboard blank shows also an edge flange with individual edge flange segments on which the cover film is then attached. In addition, the edge flange is outside according to the invention shaped so that the edge flange segments in close the seal position. For this have the individual edge flange segments with intersection lines on which the angular position is then based of the edge flange can be determined. Through the Use of prefabricated cardboard blanks results the advantage that when erecting the cardboard blanks in contrast, no material thinning occurs to the well-known bowl. This is due to the disadvantages of material thinning of food packaging. The fact that the edge flange segments in the sealing position close together, one results closed edge flange surface, which then to a secure sealing of the cardboard blank become.

Instructs the plastic composite film 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, especially one Copolymer of ethylene with 6% methacrylic acid, which is partial (50%) are neutralized with Na or zinc ions (Surlyn A) on, a flexible composite is used, whose oxygen permeability is determined in advance can be and also in the embedded state is not changed. Therefore, one can be significantly thinner Held EVOH layer in a flexible composite embedded is used.

Will the food packaging according to claim 6 preferably with a cardboard blank equipped of a recyclable or preferably two-layer cardboard, so can food packaging be produced which is suitable for a special one on the outer layer of the cardboard blank advertising effective print.

Further advantageous embodiments of the food packaging are the subject of the remaining subclaims 3 to 5.

The method according to the invention can be used create a container that when entering in the vacuuming or sealing station except for one side, namely the upper side, oxygen-tight is. In addition, the plastic-lined Cardboard cutting also in the area of specially designed edge flanges has particularly high dimensional stability, this edge flange between the seals of the closed sealing tool be safely recorded, so that according to the invention only the inner cavity of the molded one Carrier shell must be evacuated. The power consumption the packaging system for generating the evacuation the cycle number of the packaging system is reduced can be significantly increased.

It has been shown that through the Edge flanges that are close together and form almost continuous saddle bars, a high Stability is achieved and even when filling the Bowl of food an uncontrolled break or there is no uncontrolled tearing of the webs can. The operational reliability of the device can furthermore be raised in that that lie between the interior of the carrier shell as Sealing webs formed edge flanges from below by means of aligned parallel to the transport direction Slide and guide rails are supported. Advantageous is also the training that the container in. the filling section from below using a synchronous with the conveyor belt running support be supported.

With the method according to the invention the proportion of non-recyclable plastics reduce to a minimum, with appropriate Choice of materials for the carton blanks additional advantage of problem-free self-rotting results.

Finally, the power consumption of the packaging system especially in the area of the forming station reduced because the time required to warm up a common hard film of approx. 500 to 1000 µm (PVC, Polysterol or polyester) can be significantly reduced can. The required inherent stability of the container is described according to the invention by using the Carton cut achieved, especially if the Cover film on the plastic film that the cardboard blank lines, is attached.

The food packaging that can be produced using the process have increased dimensional stability and they are highly torsionally stable.

Fig. 1 ist eine schematische Seitenansicht einer ersten Ausführungform der erfindungsgemäßen Verpackungsanlage.

Fig. 2 ist eine perspektivische Ansicht aufgerichteter Kartonzuschnitte.

Fig. 3 ist in der Seitenansicht im vergrößter Maßstab die Formstation der Verpackungsanlage.

Fig. 4 ist eine Vorderansicht der in Fig. 3 gezeigten Formstation mit eingebrachtem Kartonzuschnitt reihenartig aneinanderliegend angeordnet und der Kunststoffverbundfolie, die für die Auskleidung zugeführt ist.

Fig. 5 ist eine perspektivische Ansicht von seitlich in Reihe angeordneten Kartonzuschnitten, die bereits mit der Kunststoffverbundfolie ausgekleidet sind, wobei in einer in etwas vergrößtem Maßstab dargestellten Schnittansicht entlang der mit dem Pfeil eingezeichneten Linie der reihenweise angeordneten Kartonzuschnitte der wärmekaschierte Randflanschbereich dargestellt ist.

Fig. 6 ist eine Vorderansicht der Vakuum- bzw. Versiegelungsstation mit eingesetzten Kartonzuschnitten, die bereits mit Kunststoffverbundfolie ausgekleidet und damit zu einer Reihe verbunden sind.

Fig. 7 ist eine perspektivische Ansicht der zusammenhängenden Kartonzuschnitte mit Kunststoffverbundfolie und abgesiegelter Deckelfolie, wobei in vergrößertem Maßstab die Einzelheiten des Kartonzuschnittes und der anhaftenden Schichten deutlicher dargestellt sind.

Fig. 8 ist eine perspektivische Ansicht einer gebrauchs- bzw. verbrauchsfertigen Schale.

Fig. 9 ist eine perspektivische Ansicht einer Schale mit teilweise abgelöster Deckelfolie.

Fig. 10 ist eine perspektivische Ansicht einer Schale mit teilweise abgelöster Deckelfolie und teilweise herausgelöster Innenfolie.

Further advantageous embodiments are the subject of the remaining subclaims. The invention is explained in more detail below with the aid of schematic drawings.

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

Figure 2 is a perspective view of erected carton blanks.

Fig. 3 is a side view on an enlarged scale, the molding station of the packaging system.

FIG. 4 is a front view of the molding station shown in FIG. 3 with the inserted cardboard blank arranged in rows one after the other and the plastic composite film that is fed for the lining.

5 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, shown on a somewhat enlarged scale, along the line of the cardboard blanks arranged in rows with the arrow.

Fig. 6 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 a row.

FIG. 7 is 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 on an enlarged scale.

8 is a perspective view of a ready-to-use tray.

Fig. 9 is a perspective view of a tray with the lid film partially detached.

10 is a perspective view of a bowl with the lid film partially detached and the inner film partially detached.

In Fig. 1 is the side view of the packaging system shown, consisting essentially of four stations exists, namely a molding station (FS), a filling section (BS), the sealing and vacuuming station (VS) and a preferably two-stage Separation system (80, 81), the latter also can be designed in one stage. Transporting the in Row of precisely arranged cardboard blanks to the individual stations is preferably carried out via a Transport chain or when used on a so-called "Tray-Sealer" via a specially trained water sports band with recording rooms for the side by side Carton blanks. As shown in Fig. 1, for relieving the transport chain 48 so-called Support belts 50 below the conveyor chain 48 be additionally provided.

Those prepared in a magazine or dispenser 12 erected cardboard blanks 10 fall clocked with the support of a proven, pneumatically working Device 9 on a ribbon. Likewise the erected carton blank is clock-controlled under a stamp device with a stamp 11 transported where the edge flange 52 in particular the Edge flange segments 54 before inserting the individual Cardboard blanks 10 broken into the forming station FS becomes. The stamp 11 is designed such that the Edge flange 52 in the depending on the fermentation cut at the ends the edge flange segments 54 possible sealing position is broken with a corresponding inclination. After this Breaking the edge flange segments 54 becomes the cardboard blanks transported to a transfer position from which from them is controlled by suction air support a special transport stamp 13 in the open Recording form of the forming station FS can be placed. At the Tray sealer system will cut the carton into appropriate Recording rooms of the transport chain 48 set.

On the other hand, the breaking of the edge flange segments 54 can only be carried out in the forming station FS one procedural step can be saved. Indeed are the constructive requirements for such Forming station considerably higher. In this case, however be ensured that the edge flange segments 54 are broken only shortly before they are sealed.

If a method according to the known tray sealer is used, so the transport chain 48 transports the rows carton blanks arranged closely together 10 then clocked into the forming station FS. The forming station FS can also be designed, for example a station operating according to the skin system Forming, filling and closing system according to Multivac CD6000.

Starting from this situation, the rows are narrow stacked cardboard blanks arranged next to each other are in the forming station, the begins actual forming or lining process of the Cardboard blank 10 using plastic composite film 34. In the molding station is lining the inner surface of the cardboard blanks arranged in rows 10 with an oxygen-blocking plastic composite film 34 performed. The plastic composite film 34 is provided by an endless roll 33, which over the infeed line of the packaging system on a Bracket is attached via pulleys on the in cardboard blanks arranged in rows in the admission forms 10 essentially parallel to the transport chain drawn.

When using a tray sealer, the transport chain leads 48 the rows arranged in the reception rooms of the transport chain resting erect Cardboard blanks 10 under a forming station FS, its working principle for lining the inner surface the cardboard blanks 10 with the plastic composite film 34 on a form, fill and seal machine used iso-pack system from MULTIVAC equivalent.

Then the packaging container by means of Transport chain 48 in the area of a filling line BS transported, the filling line BS each is designed according to the number of filling steps.

To relieve the transport chain 48, the now connected by the plastic composite film 34 Carton blanks 10 by a support tape 50, that works in sync with the transport chain become.

The filled run from the filling line BS Trays in a vacuuming and sealing station VS on, with one of the endless roll 22 via a deflection roller system guided cover film 20 in essentially parallel to the transport route into the vacuum and sealing station VS is supplied. How the vacuuming and sealing station works VS corresponds to conventional systems, e.g. the Multivac and is described in detail in FIG. 7.

After sealing the filled packaging container these are in turn transported using the transport chain Separation stations 80, 81 fed, the in Row of continuously arranged cardboard blanks 10 again by a conveyor belt working in sync 50 can be supported.

As can also be seen in FIG. 1, the Transport route of the transport chain 48 and the support belt 50 from the donor to immediately behind the two-stage Separation station 80, 81, so that the entire Plant works in time.

The peculiarity of the packaging device exists now in that on the one hand a specially designed Cardboard blank 10 is used and another this cardboard blank 10 in a special way and Way, namely as a specially designed semi-finished product is fed to the packaging system.

Contrary to conventional designs of such packaging systems is already a through the donor 12 preformed and more stable due to, for example, gluing Cardboard blank 10 with top edge flange 5z fed. The fed to the packaging device According to the invention, semi-finished products have specially designed ones Circulation flanges, in particular edge flange segments 54 with coordinated miter lines, which are broken by the stamp 11 and depending on Fermentation line in the sealing position are inclined. The decisive factor here is that the edge flange segments 54 can only be broken or inclined as far until the edge flange segments 54 are flush with one another. This results in close contact precisely fitting sealing surfaces on a designated Seal device can rest and thus a sufficient for lining with plastic composite film provide a large sealing area.

In Fig. 2 erected, rows of cardboard blanks 10 are shown in perspective,
an optionally provided recessed grip GM can also be seen, for which a special edge flange side section 24B can be provided. Furthermore, overlap sections 55 between adjacent wall sections of the carrier shells can be seen. However, there is no overlap in the area of the edge flange 52, so that a coherent, stepless sealing surface can be created.

3 it can be seen that how the tool halves in the FS forming station 16 and 18 with the rows lying next to each other Carton blanks interact and by means of a Heater 72 the interior or surfaces of the row adjacent cardboard blanks 10 with line the plastic composite film 34.

The tool of the forming station FS, which according to the so-called Skin process works, consists of a sub-mold 16 and an upper mold 18, which corresponds to the 3 shown in Fig. 3 clocked apart and moved together become. Here, the lower mold 16 preferably a profile for a positive fit the cardboard blanks 10 so that the edge flanges 52 the Cardboard blanks 10 are supported in a sealed manner. The Upper form 18 is also designed so that a Heater 72 can be added. At 73 and 73A are recesses in the upper and lower part 16, 18 shown, which is designed according to the recessed grips GM are.

4 is the front view of the molding station FS shown, the lower mold 16 web-like inserts 66th has whose shape has a cross-section of the series arranged and erected carton blanks 10 adapted is. Here are the close to each other Edge flanges of adjacent cardboard blanks 10 these ridge-shaped inserts, so that when the tool halves are closed 16 and 18 the individual cardboard blanks additionally through the intended mold inserts 58, their surface contours fits the shape of the individual carton blanks corresponds, are positively supported. The How the forming station FS works, in particular that The skin procedure is briefly described in the following procedure:

If a series of erected cardboard blanks, which are close together with their edge flanges and thus form a saddle-shaped pad, into the molding station using a denester system FS introduced and the edge flange segments 54 fit exactly aligned, the one previously moved downward moves Lower tool part 16 of the forming station FS in Up arrow direction. When moving the lower part of the tool together 16 against the upper tool part 18 is in Tool upper part 18 created an almost complete vacuum. The row-shaped over the closely spaced arranged cardboard blanks 10 lying plastic composite film 34 is thereby full-surface on the heating plate 72 put on and warmed up.

After the specified heating time has expired Tool upper part 18 while evacuating the Tool lower part 16 ventilated. By this change there is a differential pressure of approx. 1 bar, which is a full-surface heat lamination between the plastic composite film and causes the cardboard blank inside (dashed line 34A).

Now that the inner surfaces of the closely lined up Cardboard blanks with the plastic composite films is lined, the molding station FS is clocked opened, which is now through the plastic composite film single cardboard blanks connected together released and for filling with the transport chain 48 to be carried on.

In Fig. 5 is that due to the close to each other Cardboard blanks 10 formed, with plastic composite film 34 lined and coherent on the inside Carton blank row shown like this the forming station FS leaves. As can also be seen, covered the plastic composite film 34 also the grip hole GM in the flange area 24B.

In the sectional drawings also shown along the edge flange 52 of a cardboard blank 10 with cardboard blank composite film 34 lying thereon are the the individual layers forming the composite film are shown. The plastic composite film 34 has an oxygen barrier layer 36, preferably made of polyvinyl alcohol (EVOH) and a sealing layer 38, preferably made of peelable polyethylene and an adhesive layer 37, preferably made of modified polyethylene. It has It has been shown that the inner coating of the food packaging forming carrier material extremely thin can be executed. The film thickness is preferably in the area of the remaining wall thicknesses in the base radii between 25 and 30 µm.

The plastic composite film 34 can also are structured and controlled in their behavior, that after using the packaging from the cardboard carrier can be replaced so that for disposal or recycling pure components are available. For this the finger hole recess GM also serves according to the invention.

After leaving the forming station FS, the contiguous cardboard blanks 10 the filling station along the filling line BS, meanwhile they are filled with the food to be packaged. The transport of the connected cardboard blanks 10 is done through the shared facility at intervals. Run from the filling line BS the filled cardboard blanks 10 into the vacuum and sealing station VS, in which they from the lower part 16 by means of appropriate mold inserts be included (see Fig. 6). Such a vacuum or sealing station of the conventional type from a lower part 16 and an upper part 18, the clocked together and moved apart. The Lower mold 16 preferably has a profile for complete Inclusion of the cardboard blanks designed according to the invention 10 such that the edge flanges of the shells can be supported so sealed. The top is designed so that the line pattern Heating plate 74 movable in the vertical direction can record.

The line pattern is designed so that it covers areas defined at which a seal of the cardboard blank edge flange done with the cover film 20 should.

6 is intended to function as such a vacuum or sealing tool in the invention Show effort. It can also be used for this process already known and proven conventional system be used with minor changes. The 6 shows the lower mold 16 with the web-like inserts 66, the shape of which is a cross section of between two adjacent flanges of the cardboard blanks 10 forming saddle strips is adapted, so that when the tool halves are closed 16 and 18 the connected cardboard blanks 10 through the intended mold insert 58, its surface contour corresponds to the shape of the other cardboard blank, are positively supported. At 70 are Designated seals against which the edge flanges or the saddle bars of the connected cardboard blanks 10 in the retracted state of the tool 16 and 18 so that the individual cardboard blanks are vacuumed, in this state the food already included, can be carried out.

With 74 heating devices are referred to, which are accommodated in accordance with a pattern aligned with the edge webs in the upper mold half 18, so that when the mold halves 16 and 18 are moved together, the cover film 20 is welded to the relevant edge flanges of the individual containers in such a way that a circumferential one continuous sealing surface comes about. 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 N ₂ / CO _2, usually in a ratio of 70:30, can also be used. The heating plate 74 located in the upper part of the tool 18 is preferably designed with relief-shaped sealing webs, the cover film being sealed by the action of heat and pressure with the sealing coating of the peripheral edge flange and the resulting saddle webs of the connected cardboard blanks.

In Fig. 7 it is shown how now with food filled, sealed and coherent cardboard blanks 10, the vacuum and sealing station have left.

As can be seen from the selected hatching, is the entire plastic composite film 34 on the intended Sealing surfaces welded to the cover film 20. Only in the area of GM provided recessed grip in the rear edge flange area (seen in the running direction), is characterized by a special Design of the sealing tool with the seal the plastic composite film 34 with the cover film 20 prevented. This enables the use of the punched out the rear edge flange Grip hole trough GM and not at this point the plastic composite film 34 sealed cover film 20 the subsequent detachment of the film cover or the removal the plastic composite film from the cardboard blank 10th

After leaving the vacuum and sealing station VS are the over the lidding film and Plastic composite film 34 connected, filled Cardboard blanks of a preferably two-stage design Separation system 80, 81 fed.

It is also possible to have a complete punching and separation of the individual food packaging use. In the case of complete punching, this is not necessary the second stage of separation. After leaving the The individual carton blanks are located in the singling station as shown in Fig. 8.

With the food packaging described above succeeds it, depending on the desired design, on average about 20 g per food packaging save on plastic that is no longer usable, i.e. about 70% of what conventional packaging does Kind of accrues.

The working width of the device is self-evident not limited. However, it has been shown that the widths are at least about 420 mm should be based on the economics of the device to maintain a particularly high level.

The cover film 20 is preferably also made of a Plastic composite film 34 is produced, which has an oxygen barrier layer contains which on the the cardboard blank facing side of a peelable plastic layer preferably made of modified polyethylene is covered. This layer then forms with the plastic composite film 34 over sealing webs of the edge flanges the sealed seams.

The film layer facing the heating or sealing element 72 is preferably of a film quality particularly high melting point or a heat barrier Layer formed, which preferably contains polyethylene and which lies over the oxygen barrier layer in order to Seal with the mold base for adequate Shape and surface stability during the sealing process to care. Because the sealing layers of both the cardboard blank surface as well as the cover film 20 preferably "peelable" are coordinated when sealing these two sealing layers one fixed connection that largely without destroying the Korton tailored film 34 can be peeled off by hand (see Fig. 9).

Of course, are different from the previous one described embodiments possible without the Leaving basic ideas of the invention. That's the way it is of course, the number of feeds lined up Cardboard blanks per row or work cycle to vary as desired.

It is also conceivable that the rows of plastic blanks after leaving the forming station FS via a special device were made sterile or sterile. This is advantageous a so-called "hydrogen peroxide shower".

Because of the method according to the invention used both for the oxygen-tight plastic composite film as well as with the oxygen-tight cover film 20 can be a composite combination of films of the polyolefin group Find application. This composite combination can be recycled as mono film. It has shown that in the field of PE heavy film production this regranulate can be used as filling material can.

Due to the interior coating made using the plastic composite film is the stability of the Cardboard cut especially on the Edge flanges improved considerably. After solidification, the plastic composite film loses 34 considerable flexibility and stiffens the whole Cardboard cut additionally from the edge flanges.

Through the subsequent sealing with the cover film The cardboard blank is cut over the circumferential edge flanges an additional connection stiffness or torsional stiffness.

An extremely secure seal with the Barrier composite film lined cardboard blanks through the barrier layer cover film created by the fact that the circulating Edge flanges close together, so-called Form saddle bars with a sealing surface that is increased to twice that of conventional ones Edge flanges.

Since the complete available sealing surface, which with the sealing side of the barrier plastic composite film 34 is heat-laminated as a sealing surface with the cover film 27 is available, is by the carried out only after sealing Separation of the packs is always sufficiently wide Space for the formation of a secure sealed seam is maintained.

With individually fed carton blanks, the this particular inventive design of the edge flange may not have, due to tolerances when fixing the cardboard blanks in the process or due to manufacturing-related fluctuations the cardboard blank design a uniform width and therefore not achieve sufficient secure sealing surface become. The separation of the oxygen-tight film inner component from the actual stability-giving Cardboard cutting is another essential point of the Invention (see Fig. 9). The inside of the Cardboard blank lining plastic composite film is with the fibers of the inner walls and the bottom of the Cardboard blank connected heat-laminated.

By known methods, for example the Multivac Skin system, in which the heated, thus made plastic Plastic composite film with the specially trained Laminating layer, which is preferably a Surlyn blend from Dupont or a mixture (PE type) with a particularly high (preferably over 20%) ethylene vinyl acetate content contains, the plastic is made Composite film due to the corresponding pressure difference the cardboard blank inner surfaces pressed and can in the fibers of this inner surface penetrate.

The cover film 20 is over the peripheral edge flanges and the saddle bars of the rows connected Cardboard blanks as described in the procedure are coated with a sealing layer, after evacuation or gassing in the sealing station firmly connected to the lower part of the packs.

The intended semi-oval punching (GM) of the rear edge flange lying in the transport direction and the corresponding design of the sealing tool in this area creates the possibility of a so-called Grip tab that does not come from at this point formed with a cover film sealed with a lining film the entire grip hole GM To remove the composite from the then pure cardboard blank, which is then compostable by type.

To the area of application of food packaging also includes peeling off the cover film from the sealing bars to open the pack to its contents easy to remove without tools. This can through a special design of the sealing tool carried out in the sealing station without major conversion work become.

In this case, the consumer releases the cover film as far from the sealing surfaces until it is the filling material can be easily removed (see Fig. 10). The plastic composite film and the not completely peeled off lid film are then together over the handle tab from the actual Cardboard cut to the intended one Handle hole recess detached. This makes the variety Separation takes place and the individual materials can be used for further processing.

The invention thus enables food packaging in the form of a stable cardboard blank with an all-round peripheral flange that is specially trained and about by means of a preferably oxygen-blocking cover film the container is hermetically sealed.

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

In the process preformed and dimensionally stable Cardboard blanks fed from a dispenser system or in the case of use via a so-called Tray sealer, i.e. from the donor directly into the admission forms the transport chain of a tray sealer. These cardboard blanks are in one Forming station with a plastic composite film, preferably contains an oxygen barrier layer, lined.

Those arranged in a row close together Cardboard blanks are used to increase stability via connecting webs with the edge flanges of the container collapse after being lined up integrally connected so that the container rows next to each other and clocked synchronously Go through packaging lines and sealed together become.

Claims (20)

1. Method of producing oxygen-tight packaging for food in a food package having a carrier tray with a peripheral marginal flange which is lined internally with a plastic composite film and in which the interior of the carrier tray is hermetically sealed by means of a preferably oxygen-excluding covering film, wherein the carrier tray is a cardboard blank (10) with a base portion and a plurality of wall portions, and the marginal flange (52) adjoining the wall portions has individual marginal flange segments (54) for fixing the covering film (20), wherein each marginal portion (52) of the carrier tray has a marginal flange segment and is shaped externally so that in the sealing position the marginal flange segments (54) adjoin one another via mitre-cut lines so as to be flush, and wherein for stabilisation the wall segments of the carrier tray which merge into the marginal flange segments (54) partially overlap and are fixed in position by means of overlapping portions (55), whereby in the method cardboard blanks run synchronously through a moulding station (FS) which is followed for completion of the package by a filling line (BS) and a vacuuming and sealing station (VS), characterised in that the upright cardboard blanks (10) are disposed in rows in the moulding station (FS) and the marginal flange segments (54) of the marginal flange (52) are broken before introduction into the moulding station.
2. Method as claimed in Claim 1, characterised in that the cardboard blanks (10) are delivered in rows with upright marginal flanges (52) to the moulding station (FS).
3. Method as claimed in Claim 1 or 2, characterised in that the marginal flanges (52) are pressed into their sealing position in the moulding station (FS), so that the marginal flanges (52) lie close alongside the neighbouring cardboard blanks (10).
4. Method as claimed in one of Claims 1 to 3, characterised in that the lining of the inner surface of the cardboard blanks (10) takes place in rows and by means of a plastic composite film (34) which covers the entire sealing surface of the marginal flanges (52), wherein following the moulding in of the plastic composite film (34) transport to the filling station (BS) takes place in a synchronised manner by means of a conveyor chain (48).
5. Method as claimed in Claim 4, characterised in that the plastic composite film (34) is moulded into the cardboard blank (10) by the production of a pressure difference and is firmly hot-laminated to the marginal flanges (52) and the inside of the cardboard blanks (10).
6. Method as claimed in one of Claims 1 to 5, characterised in that the cardboard blanks (10) which are held together by the lining plastic composite film (34) are preferably continuously welded to a covering film (20) over the marginal flange (52) in the vacuuming and sealing station (VS).
7. Method as claimed in Claim 6, characterised in that in the region of a gripping recess (GM) formed from the trailing marginal flange of the cardboard blanks the covering film (20) is welded to the plastic composite film (34) only over a part-region (TB) of the overlap extending into the gripping recess (GM) starting from the inner edge of the marginal flange (24).
8. Method as claimed in one of Claims 1 to 7, characterised in that the plastic composite film (34) has an oxygen-excluding layer (36) preferably made from polyvinyl alcohol and a sealing layer (38) preferably made from peelable polyethylene as well as an adhesive layer (37) preferably made from a modified polyethylene, particularly a copolymer of ethylene with 6% methacrylic acid partially (50%) neutralised with Na or zinc ions (Surlyn A).
9. Method as claimed in one of Claims 1 to 8, characterised in that the covering film (20) is formed by a plastic composite film (34) which on the side facing the cardboard blank (10) has a preferably peelable plastic layer, preferably made from polyethylene, and lying above this at least one oxygen-excluding layer, preferably made from polyvinyl alcohol and a covering heat barrier layer, for example made from polypropylene.
10. Method as claimed in one of Claims 1 to 9, characterised in that the plastic composite film (34) has an initial thickness in the range between 100 and 150 µm depending upon the mould depth.
11. Method as claimed in one of Claims 1 to 10, characterised in that the plastic composite film (34) which lines the cardboard blank (10) is identical to the plastic composite film which covers the marginal flange (24).
12. Method as claimed in one of Claims 1 to 11, characterised in that the cardboard blank (10) is made from a recyclable, preferably double-layer cardboard.
13. Apparatus for carrying out the method as claimed in one of Claims 1 to 12, with a moulding station in which upright cardboard blanks, which have a base portion and a plurality of wall portions as well as a marginal flange adjoining the wall portions and consisting of individual marginal flange segments (54), are lined with a plastic film, means for synchronised transport through a filling line (BS) of the cardboard blanks which are lined internally with plastic composite film (34) by means of a lining film, a subsequent vacuuming and sealing station (VS) and a separating station (80, 81), characterised in that before the moulding station (FS) means are provided by which the marginal flange segments (54) are broken before introduction into the moulding station (FS), and that in the filling line at least two cardboard blanks (10) which lie laterally alongside one another and are held together by marginal flanges (52) can be synchronously delivered via a transport means to the vacuuming and sealing station (VS).
14. Apparatus as claimed in Claim 13, characterised in that additional support and guiding means, preferably in the form of vertically oriented fillets which can preferably be oriented in terms of height, are provided for the marginal flanges (54) which lie adjacent to one another in order to prevent uncontrolled flexing.
15. Apparatus as claimed in one of Claims 13 or 14, characterised in that after take-up of the linked cardboard blanks (10) by the conveyor chain (48) the plastic composite film (34) which is suitable for forming the plastic composite film lining is drawn off from a continuous dispenser roll (32) which is disposed substantially vertically above the intake section and drawn by a guide roller over the cardboard blanks (40) which are held together by way of neighbouring marginal flanges (52) or saddle-shaped supports.
16. Apparatus as claimed in one of Claims 13 to 15, characterised in that the plastic composite film (34) drawn over the marginal flanges (52) and saddle fillets (42) of the cardboard blanks (10) are synchronously welded or sealed by sealing fillets (74) of the moulding station (FS) to the marginal flanges (52) or to the saddle-shaped support of the linked cardboard blanks (40).
17. Apparatus as claimed in one of Claims 13 to 16, characterised in that the plastic composite film (34) which is joined in this way to the marginal flanges (54) and saddle fillets (42) is continuously transported through the moulding station (FS) by the synchronised forward movement of the transport means.
18. Apparatus as claimed in Claim 17, characterised in that the plastic composite film (34) is rendered plastic by a heated plate (72) of the moulding station (FS) and thus heated is drawn into the cardboard blanks by means of a pressure difference.
19. Apparatus as claimed in Claim 18, characterised in that a supporting belt (50), by which the linked cardboard blanks are supported from below particularly in and after the filling line (BS), runs round synchronously with the transport means.
20. Apparatus as claimed in one of Claims 13 to 19, characterised in that the vacuuming and sealing station (VS) has a lower tool part (16) to receive the cardboard blanks and retain their shape precisely and a heatable upper tool part (18) with which the covering film (20) running continuously from the roll (22) into the open tool can be pressed against the saddle fillets (42) or the peripheral marginal flanges and can be welded to the plastic composite film (34) under the effect of heat.

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