EP1368241A2

EP1368241A2 - Gastight food packaging and method for production thereof

Info

Publication number: EP1368241A2
Application number: EP02764013A
Authority: EP
Inventors: Jochen Dietrich; Kurt A & R Carton GmbH RÖMER
Original assignee: PTS Consulting AG
Current assignee: PTS Consulting AG
Priority date: 2001-03-08
Filing date: 2002-03-07
Publication date: 2003-12-10
Also published as: WO2002085720A3; DE10111232A1; WO2002085720A2

Abstract

A tray for a packaging with an enclosing boundary flange is disclosed. The inner side of the tray may be lined with a plastic, in particular, a plastic composite film, including the boundary flange. A pre-prepared section forms the packaging base, the sidewalls and the boundary flange. In order to minimise the uptake of moisture, grooves (53) are stamped onto each of those sides where the angle between the wall faces of the tray is greater than on the opposite side.

Description

Gastight food packaging and process for its production

The invention relates to a food packaging according to the preamble of claim 23 and to a method for producing such a packaging according to claim 30, a semi-finished product or tray suitable therefor according to claim 1 in the form of rigidly arranged and film-lined trays and a method for producing it according to claim 24. as well as a shell part cutting element on which the tray is based, and a collar part cutting element according to claim 35.

A large number of food packaging are on the market, with special efforts being made recently to minimize the proportion of non-recyclable plastics in such packaging. 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 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 strength 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 required oxygen barrier and is embedded between the carrier film and the sealing layer when a so-called rigid film bond is used, shows a significantly poorer molding result, 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, be equipped with a correspondingly strong oxygen barrier layer, which results in additional costs. 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 leads. In the sealing station, a cover film is sealed onto 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. However, it has been found here 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 manufactured using the cold press process are largely oxygen-proof by means of a barrier film sheeting, folds are formed due to the material displacement which has occurred as a result of the cold press process. These folds extend into the edge of the flange area of the container, making 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 cuts from coated cardboard are placed on a separate unit. gat 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 really 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 be completely shielded at the open cut edges.

However, there is a need to create a food packaging according to the preamble of claim 23, which can be produced with little change-over effort on conventional horizontal form, fill and seal systems, with the proportion of plastic being reduced to a minimum, at the same time however, the stability of the container and the oxygen density can be kept at a particularly high level.

Another need is to develop a method for the oxygen-tight packaging of food 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. These needs are taken into account with the subject of the earlier patent application P 196 54 230. Furthermore, PCT patent application W099 / 67143, the content of which is expressly referred to here, proposes food packaging and a method for its production and a device for carrying out the method with a suitable semi-finished product or tray.

The food packaging proposed there has as a load-bearing basis a tray lined with a thin plastic composite film, which is composed of a first cardboard blank that can be erected automatically and a second cardboard blank that is glued to it via spreadable adhesive tabs. The second cardboard blank forms an uninterrupted collar of the tray and thus provides a continuous surface for sealing the packaging. The continuous, ie uninterrupted collar has advantages already when attaching the plastic film lining the inside of the packaging, since the best conditions are created 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 ruled out even at higher working speeds of the packaging machine. The decisive advantage achieved there can be seen 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 radial channels having a capillary shape The advantage of using prefabricated cardboard blanks is that there is no thinning of the material when erecting or folding the cardboard blanks, in contrast to the known tray. This overcomes the disadvantages caused by the thinning of the material with the food packaging according to the invention. In this way, in the case of these gas-tight or oxygen-tight packagings, the tightness produced via the circumferential sealing flange is also ensured over a longer period of time. The circumferential flange with its adhesive tabs also proved to be a good stabilization of the packaging tray, even if the connection between the tray components was only made selectively or in certain areas and not over the entire surface.

However, such gas or oxygen-tight packaging with folded cardboard blanks as a supporting element and lining plastic composite films as an oxygen barrier still have certain weaknesses in the overall concept, in particular with regard to their usability in different, in particular moist environments, and with regard to the design options of the packaging geometry.

It is therefore an object of the present invention to provide a food packaging of the type described above, which is distinguished by the advantages described at the outset and additionally by the fact that, as far as possible, they do not damage the plastic film composite, and in particular the Oxygen barrier layer is still experiencing the protective Cardboard packaging in order to be able to carry out the packaging or the underlying tray with a steeper flank angle and / or greater depth of the packaging and / or their relationship with respect to an increase in the volume content of the packaging in relation to the space occupied by the packaging , In this context, the thermoforming and adhesive properties of the lining film must also be further optimized.

Another object is to provide a method for producing such a food packaging that can be carried out according to a simple process.

Since, in practice, the ready-to-fill prefabrication of packaging trays, and the filling and packaging of the food packaging are carried out separately, another object of the present invention is to use gas-tight

To provide trays coated with film materials and a suitable process for their prefabrication.

This object is achieved with regard to the tray with the features of claim 1 or 24, with regard to food packaging with the features of claim 23 or 30 and with respect to the tray part cutting element on which the tray is based with the features of claim 31 and the collar part cutting element solved with the features of claim 35.

According to the invention, one on which the tray is based

Rough cuts on the intended fold edges have grooves that are embossed against the direction of the fold. As a result, the or underlying blank semi-finished product and the associated folding, both a tear and the build-up of a tensile stress leading to the material tear on the outside of the folded edges can be avoided. During the folding, the embossed grooves provide enough material to keep the cut in a relaxed state. Additional, problematic measures such as perforation or scoring can be omitted, since the creasing dictates a desired course of the fold. Since the creasing bulges inwards, even after the fold, a web remains on the inside of the prefabricated tray at the folded edges, so that when the lining plastic is deep-drawn, there is no need to pull all the way into the corners, thereby reducing the material thinning in the film can. Overall, the advantages mentioned lead to an improved suitability of the tray according to the invention in relation to an improvement in the ratio of packaging size to packaging volume content, since both the flank angle at which the side walls protrude from the bottom of the tray and the depth of the tray and the ratio of these two. Sizes can be enlarged relative to one another compared to conventional packaging of this type.

According to the invention, problems which are attributed to perforated or scored fold edges no longer occur. Accordingly, there are no predetermined breaking points in the erected state. Gaping, which is additionally reinforced when the material is folded, with the angle of the fold, i.e. the flank angle of the packaging, is ruled out, so that the packaging is no longer weakened at the folded edges and moisture is no longer penetrated can come. That is why the tray is suitable also for use in extremely humid, steamy environments.

Another surprising positive effect of the creasing according to the invention relates to the footprint with which the packaging rests on the ground:

The grooving results in a tendency of the packaging base to bend, which at least partially prevents the base from being soaked up on a wet surface.

Advantageous developments of the invention are the subject of the further claims.

The fact that the creasing of the folded edges according to claim 2 is stamped only on edges that are present on flanks that are strongly angled in the assembled state, prevents unnecessary creasing on edges that are present on flanks that are only slightly angled, and thus saves processing time and effort become. The edges with only slightly angled flanks can still be folded without damage, for example by pressing them in using a pressure stamp.

An embodiment of the tray according to the invention as claimed in claim 3 has, as a supporting base, a cardboard blank lined with a thin plastic composite film, which can be erected automatically and the inner region 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 in the sealing position close together. 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. The use of prefabricated blanks results in the advantage that no material thinning occurs when erecting the cardboard blanks, in contrast to known trays. 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 close flush 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 packaging, particular care must be taken to ensure that the tightness produced by the sealing flanges is guaranteed even over a longer period of time. Otherwise, the food technology requirements can no longer be met. The quality of the seal is determined by the accuracy of the blanks. In other words, the danger of ambient air entering the packaging via capillaries in the sealing flange in the medium term 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.

In an alternative embodiment, the tray according to the invention is therefore equipped with an uninterrupted collar, which is thus a continuous surface for sealing the packaging provides. The continuous, ie uninterrupted collar has advantages already when attaching the plastic film lining the inside of the packaging, since the best conditions are created 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 ruled out even at higher working 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 the working speeds of the packaging machine can be increased considerably in this way 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.

This 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 tray, 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 design results from the developments of claims 5 and 6. Because side tabs can make a significant contribution to improving stability. In addition, slots between the side wall portions of the Avoid trays on which the film could be damaged by external influences, such as pointed objects; compared to a known intermediate product of this type, a potentially higher oxygen tightness is achieved. In addition, the special 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.

A weak point in the packaging on its side edges, on which there is no continuous carrier material, has accordingly been eliminated. Slots that are no longer present between the individual side wall sections, the longer the deeper the packaging becomes and which can only be kept small by a precisely fitting and therefore slow and expensive erection of the cardboard blank, are effectively eliminated. With moist storage, rough handling of the pack, but also especially with regard to fumigated packaging, in which the gassing creates a corresponding internal pressure, there is no longer any danger of injury to the plastic film and thus the gas leakage of the packaging.

Basically, it is possible to form a continuous collar that can be put on as a closed ring. With the development of the edge flange with tabs according to claim 6, however, the fitting of the collar part is facilitated and the stability of the tray is further increased.

The side flaps are preferably carried out on every second side wall section on both sides. It can be achieved that the The area of overlap of the side flaps with the adjoining side wall sections becomes maximum and that the side flaps are either designed only on the inside or only on the outside. As a result, a surface can be flat, which is particularly advantageous in terms of printing on the outer packaging surface or lining the inner surface of the packaging tray.

If the tabs of the edge flange and the side tabs according to claim 8 do not overlap when the tray is assembled, a further improvement can be achieved with regard to the goal of creating a packaging interior and exterior surface that is as flat as possible.

If, according to claim 9, the tabs of the edge flange and the side tabs of the side walls are fastened, 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.e. can be used as information and advertising space.

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

If the tray according to the invention is preferably equipped with a cardboard blank, which according to claim 15 consists of a recyclable or preferably two-ply carton, a pre-food packaging product is created which is suitable for bearing a special advertising effect on the outer layer of the carton blank , In particular, this creates a possibility for inventing to emphasize appropriate food packaging optically.

The design according to claim 15 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 molding quickly forms an intimate connection with the surface of the shell part. In contrast, it is important for the outside of the shell part to create an appealing exterior and good conditions for the printing to be carried out as a rule.

It has been shown that the second, i.e. inner layer can easily consist of recycled cardboard, which saves costs and achieves special advantages in terms of environmental compatibility. By roughening the inner surface, an even more intimate connection of the plastic film with the

Inside the tray in a shorter time.

It is particularly advantageous to use an adhesive varnish which has a temperature band character for gluing the tabs of the edge flange and the side tabs of the side walls to the inside of the side walls of the shell part. In this way it is possible to pre-coat the cardboard blanks with the adhesive varnish, since it does not grip when it is cold, and to carry out the required gluing by briefly warming up during the assembly process. Compared to conventional methods with hot / cold glue, this can save even more time be achieved. In addition, the adhesive varnish remains dimensionally stable during a subsequent film lining of the tray at high temperatures.

In this way it can be ensured that an undesired migration of substances, which would lead to a problematic odor or taste impairment, particularly in connection with the food filling of the packaging, is avoided.

In trials, a three-layer plastic film composite has proven to be particularly suitable as a lining film in order to meet the requirements of oxygen tightness, intimate connection with the inner wall of the cardboard and good peelability of the overall film.

If 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, a flexible composite is used, the oxygen permeability of which can be determined in advance and is not changed even in the embedded state. Therefore, a significantly thinner oxygen barrier, 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. With regard to good adhesive properties, low melting point and good deep-drawing behavior, an adhesive layer made of a copolymer of ethylene with 6% methacrylic acid which has been partially (50%) neutralized with Na or zinc ions (Surlyn A) has been found to be particularly suitable ,

Extensive tests have shown that complex requirements are imposed on the lining composite film. In combination, it must have the following properties:

a. Good ductility b. Low melting point of the side facing the box. c High melting point of the side facing away from the box (sealing side to the top film). d. Good adhesion of the side of the lining film facing the box to the inside of the box. e. Controllable adjustment of the adhesive force of the

Foil to the box. f High gas barrier properties and water vapor density of the entire composite lining film. G. Good deep-drawing behavior, in particular the oxygen sealing layer and in the corners or on the edges of the tray h. Thermal properties of the overall composite, which keep sufficient heat available in the mass during the molding process, and thus make it possible to heat-laminate the lining film to the inside of the box. i. Enabling a high number of cycles on the packaging system.

This task is advantageously taken into account by the film selection according to claims 18 to 21. The risk of leakage in the case of methods conventionally used for coating the tray with the lining-plastic film composite, such as deep drawing, can be reduced, since the strong material thinning mentioned at the beginning no longer occurs here. It is avoided that the desired oxygen barrier is reduced by thinning the oxygen barrier layer in the film composite - especially in the corners and on the edges of the packaging - in particular with regard to deep trays and / or trays with steep flanks.

If ethylene methacrylate with about 9-20% comonomer content is used according to claim 18, the adhesive force can be varied analogously to the comonomer content and the melting point of the film is low enough at about 85 ° C to ensure that the adhesive layer during heating of the film composite, which is used to make the film flowable for deep drawing, is the first to soften, melts and forms an intimate connection with the cardboard wall.

If a particularly strong adhesion is to be achieved, for example in order to withstand the stresses that may occur after deep-drawing and recooling the film composite, which result from the elastomers of the film composite striving back to their starting position, the adhesive layer is made of acid-modified ethylene / acrylate polymer Resins with medium to high acid-comonomer proportions and temperature-resistant esters, especially made from Bynel of the 2000 series (eg Bynel 2002), as these resins allow strong adhesion between different materials. This material is very good for Suitable for coating paper and cardboard and adheres well to polyamide; it is therefore particularly suitable for oxygen barrier layers made of polyamide and for use in multilayer films. The melting point of the material is approx. 87 ° C - 91 ° C in the desired range.

However, it would also be the use of

Ethylene vinyl acetate polymers (EVA) conceivable as an adhesive layer, since these substances in addition to a low

Melting point (approx. 70 ° C - 95 ° C) have good adhesive properties on a wide range of materials.

A mixture of polyamide with approximately 20% amorphous nylon resin or amorphous polyamide resin is preferably used for the oxygen barrier layer arranged centrally in the film composite. By adding the amorphous polyamide resin, the layer becomes amorphous and is therefore easy to deep-draw. The mixing causes the barrier layer to thin less in the corners and therefore remains impermeable even after deep-drawing in relatively deep or steep trays. The melting point (Selar PA: approx. 250 ° C) is so high that it is guaranteed that the adhesive layer is in any case sufficiently heated until the barrier layer has warmed up.

As an alternative, a barrier layer of preferably 32% EVOH, mixed with preferably 15-20% of a thermoplastic ethylene / methacrylic (E / MAA) copolymer, the acid function of which has been partially neutralized with ions, such as Surlyn 7928, is appropriate. By admixing the thermoplastic ethylene / methacrylic (E / MAA) copolymer, the acid of which lowers the crystallinity of the plastic layer and thereby amorphizes the plastic layer Gives character, the thermoformability is increased, while at the same time a high load capacity is achieved due to the ion binding between the polymer chains.

In contrast to pure EVOH layers, which are difficult to deep-draw and greatly thin out at the corners, the improved deep-drawing behavior can achieve a good oxygen barrier effect even with steep side walls or deep trays.

For the overall thickness of the lining film composite, a low film thickness of 100-150 μm has resulted, depending on the depth of the tray and the steepness of its side walls.

The tray can be equipped with almost any shape, the particular advantages being achievable when the shell part exceeds a certain minimum depth and / or a certain steepness of the flank angle between the side wall and the bottom is achieved.

The base preferably has a rectangular shape, but a polygon shape would also be conceivable.

The inventive structure based on the tray

Food packaging is the subject of claim 23.

By sealing a tray according to the invention with an oxygen-tight cover film, which preferably contains EVOH as a barrier layer, packaging for

Provide food that is stable, that

Food preserved for a long time and does not give off a bad taste. With the method for producing the tray according to claim 24, there is a possibility of assembling the tray in the shortest possible time and with the greatest possible accuracy, lining it with composite film and making it available as individual elements for an upcoming filling and packaging process.

The operational reliability of the method can also be increased in that the edge flanges, which are designed as sealing webs and lie between the interior of the carrier shell, are supported from below by means of slide and guide rails aligned parallel to the transport direction. A further development is also advantageous in that the containers are supported in the filling section from below by means of a support belt running synchronously with the transport device.

Since the trays are preferably made locally and temporally separate from the process of filling and packaging the food packaging and thus the production of the trays remains independent of the filling and packaging of the entire packaging, they can already be sold as a preliminary product or manufactured by specialized packaging manufacturers , while the actual food packaging can be carried out by the food distributor. The manufacturing process of the tray, which is separated from the filling of the packaging according to the invention, also offers the required environmental conditions

Advantages: The trays often have to be filled in a humid and warm environment. Such environmental conditions would, however, be unfavorable in the manufacture of the trays, particularly with regard to the still unprotected against moisture, since they are still uncoated Inside of the cardboard blank. The plastic film starting materials such as amorphous nylon resins (Selar PA) for the barrier layer also attract moisture in the initial state and are then difficult to process. On the other hand, if the trays are only exposed to moisture in the pre-fabricated state, all surfaces of the tray are protected against the ingress of moisture, which means that the reject rate can be significantly reduced.

If the bonding according to claim 26 is carried out by activating a temperature-dependent adhesive lacquer located on the cut of the shell part and / or on the cut of the collar, the heating tools required for this can be easily integrated into the molds necessary for shaping the raw tray by heating them be carried out. The resultant heating of the trays thereby anticipates part of the thermal energy required for deep-drawing the lining film.

An advantageous further development of the manufacturing process results from the further development of patent claim 27. By attaching the plastic film to the edge flanges of the trays, the latter can be transferred reliably and particularly precisely into the deep-drawing stamp station. The further transport of the trays attached to the film can take place according to claim 28 via grippers of a transport device acting on the side edges of the film.

By means of the separate filling and packaging method according to claim 30, the food packaging according to the invention can be finished in a rational manner. Outsourcing the tray prefabrication brings Space savings and lower fixed costs due to unnecessary machines.

As a result of the use of the lined trays according to the invention, there is a container which is oxygen-tight up to 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 peripheral edge flange, this edge flange can be securely accommodated between the seals of the closed sealing tool, so that, according to the invention, only the inner cavity of the shaped carrier shell has to 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.

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.

1 shows a schematic side view of a packaging system for carrying out the method of producing the tray according to the invention;

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

2b shows a schematic illustration of erected cardboard blanks arranged in a row according to a further embodiment of the tray according to the invention;

2c shows an exploded view of a modification of the cardboard parts of the tray according to the invention 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;

Fig. 4 shows a plan view of the associated cardboard blank for the shell part;

5 shows the edge flange area of a tray already lined with plastic composite film;

6 shows an enlarged illustration of a folded edge according to the invention;

7 shows a schematic view of the device necessary for erecting and gluing the cardboard frame of a tray;

8 shows a schematic view of the tool of the forming station FS.

1 shows the side view of the manufacturing plant for the trays, which essentially has four main stations, namely a separating device W9, a stapling station HS for attaching a lining film 134 for prefabricated trays, a forming station (FS) in which the plastic film in the trays are molded, and preferably a two-stage Separation system 181, 182, the latter can also be designed in one stage.

Specifically, those in an erection station (AS) are prefabricated in their own process, i.e. erected and glued cardboard blanks 110 nested in a magazine or dispenser 112 and accessible from there to the separating device W9. They are placed - preferably in rows with 2 to 5 trays next to each other - clock-controlled with the aid of the preferably pneumatically operating separating device W9 onto a conveyor belt 111, with which the trays are further transported clock-controlled to a transfer station US.

Alternatively, the AufrehtStation (AS) can be used

Erecting and gluing the cardboard elements into the

The method can be integrated by connecting it upstream of the separating device W9.

In the transfer station US, 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 into the plane EKF of the plastic film 134 and into the area of the stapling station HS, in which the lining film is preferably punctually by means of a heated stamp 118 is tacked to the leading and / or trailing areas of the edge flange of the trays.

Starting from this stapling station HS, in which the prefabricated 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 molding station begins Analogous to the inline process, trays 110 supplied by means of the plastic, preferably the plastic composite film 134. In the molding station, the lining of the inner surface of the cardboard trays 110 arranged in rows with one another is carried out with an oxygen-blocking plastic composite film 134, which is explained in more detail below in connection with FIG. 8.

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, over the trays 110 arranged in rows in the receptacles essentially parallel to the transport chain 148 and runs as in the inline -Procedure from.

The number of trays lined up per row or work cycle can vary as required.

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 finished, internally coated trays are then again conveyed to the singulation stations 181, 182 by means of the transport chain, it being possible for the trays 110, which are arranged in a row in a row, 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 dispenser to immediately behind the two-stage singling station 181, 182, so that the entire Plant works in time. 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 singling station, the finished single trays are available.

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 semi-finished products or raw trays 10 passing through this production process according to a first embodiment are shown in an exploded view in FIG. 2a. According to the invention, they have specially designed edge flanges 52 which are formed by a continuous collar which is placed on a shell part 40.

FIG. 2a shows the two components of the raw tray 10 of this embodiment in the preformed state, the collar 52 and the shell part 40 in an already erected and connected, preferably glued state, immediately before the parts are assembled and connected to one another, preferably glued.

Although 40 side flaps 7a, 7b can be seen on a side wall section 43 of the shell part, which are glued on the outside to the respective neighboring side wall sections 43, the side flaps are preferably glued on the inside. Adhesive varnish 47 is applied all round on the inside of the tray, with which the appropriate heat is applied Shell part 40 can be glued to the fold-over adhesive tabs 51 on the collar.

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, so that the outside is suitable for printing and as a carrier for an adhesive varnish, whereas the Inside has a roughness necessary for the lining film to adhere well. The smoothness of the outer surface can be achieved, for example, by coating or painting.

2b shows, in perspective, erected cardboard blanks 10b according to a second embodiment, which are arranged in rows, as may be desired when the manufacturing method described above is run through. Overlap sections or adhesive tabs 55 between adjacent wall sections of the carrier shells can be seen. However, there is no overlap in the area of the edge flange or the edge flange segments 52b, so that a coherent, stepless sealing surface can be created based on the miter-cut, mutually supporting edge flange segments 52b.

Of course, deviations from the variants shown are possible without departing from the basic idea of the invention. Figure 2c shows a somewhat modified design of the blank for the tray. The continuous collar 452 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. It can be designed without tabs, but this makes it difficult to fit onto the edge flange segments 444 becomes. For this reason, tabs 452 can also be attached to the collar 452, as indicated by dashed lines in FIG. 2c, although the gluing takes place between the underside of the continuous collar 452 and the top of the edge flange elements 444 in order to facilitate fitting.

"X" denotes those areas on which adjacent wall segments 443 are connected to one another by adhesive or overlapping tabs 443 A. In this case, in the modification in FIG. 2c, a side flap is implemented on each wall segment 443. In the preferred embodiments shown in FIGS. 2a, 2b, on the other hand, adhesive tabs or side tabs are on both sides of each second wall segment 43, 43a.

In FIGS. 3 and 4, the blank parts or the blanks from which the tray components of the first embodiment are formed are shown in detail in the top view.

The cut element of the collar forming the edge flange 52 according to the embodiment of the tray of a shell part and a collar shown in FIG. 2a is - as shown in FIG. 3 - cut such that an annular collar 52 has trapezoidal and triangular tabs 51 on the inside, which are coated with temperature-sensitive adhesive varnish (indicated by dashed lines) and hang on the edge flange over fold edges or predetermined crease lines 8a. The adhesive varnish is applied to the smooth, lacquered or coated surface of the cutting element, since it adheres better there and is not absorbed by the roughened cardboard on the opposite side. The collar is so with a corresponding shell part glued so that the roughened surface of the collar part points into the interior of the tray in order to provide a rough surface for better adhesion of the lining film. The predetermined folding lines 8a are designed as grooves 53 stamped into the cardboard blank.

Such a groove 53 stamped into the box is shown in FIG. 6. The creasing is carried out in the direction of the bend (indicated by the two arrows) in order to avoid tension on the outside of the fold edge or the predetermined fold line during the erection of the blank or during the fold. It is shown that when the cardboard blank is erected (bending in the direction of the two arrows), the material compressed in the groove 53 leads to the fact that when the cardboard is erected there is no tear, but a material thickening on the inside of the angle formed.

However, creasing in the opposite direction to the bend is also possible. For example, the circumferential collar cut shown in FIG. 3 is preferably grooved on the side which, when the tray is assembled, points outwards. It is thereby achieved that the bead which arises during the folding of the folding grooves does not stand in the way of a precisely fitting insertion of the circulating collar semi-finished product into the erected semi-finished shell product. A bursting of the cardboard on the inside can be accepted since it is protected by the lining film when assembled.

The shell part 40 of the two-part embodiment of the tray is formed from a cutting element according to FIG. 4. On a bottom part 41 hang over grooved Kink lines 8a, the side wall sections 43, which touch in the erected state. On every second side wall section 43 there are side flaps 7a, 7b on both sides, which are coated with adhesive varnish (see dashed line in FIG. 4) with which the side wall sections are glued together after the cutting element has been erected, so that a stable shell part is produced. In this case too, the adhesive varnish is applied to the smooth surface of the cutting element, so that the side or adhesive tabs 7a, 7b lie on the inside of the wall sections 43, in order not to hide a pressure applied to the outside of the cutting element.

The fold edges, or crease lines 8b between the side flaps 7a, 7b and side wall sections 43, which have such, can be grooved or non-grooved, since the kink angle between the side wall section 43 and side flaps 7a, 7b is relatively small in the erected state. In order to ensure a secure shape, these fold lines can also be perforated or scored if small angles occur between the corresponding side wall sections 43 which make it difficult to fold or erect the cutting element into the desired final shape.

Because the angled tabs 51 are connected, preferably glued, to the side walls 43 when placed on the shell part 40, the latter are stabilized by the edge flange 52. The fact that the side walls are glued to one another with the side flaps 7a, 7b further increases the stability of the tray. The result is that the material used - low carton weight - results in a high torsional rigidity of the tray. Dash-dotted lines indicate edge flange elements 52b which are alternatively attached to a cutting element of a tray to be produced from only one cutting element. By appropriately shaping the edge flange elements 52b such that they are miter-supported in the sealing position, the stability requirements are met with a sufficient fit. Such a cutting or cutting element could, of course, optionally also together with a

Use collar part cutting element, for example by means of an adhesive in the area of the edge flange

(and on any existing adhesive tabs on the

Collar part cutting element) to enable a continuous, continuous edge flange.

The device required for erecting and gluing the cardboard frame of a raw tray 10, a base shape and a heatable stamp, is shown in a schematic view in FIG. In a bottom shape

316, the cardboard blank 40 is erected and precisely stabilized 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.

Forms 316, 318 are moved together after an adhesive, preferably a temperature-dependent one, is applied to one of the surfaces of side walls and / or tabs that overlap

Adhesive varnish was heated and thus made adhesive. For this purpose, a heating device 320 is provided, which is designed as an electrical heater with an ohm 'see consumer 321, which is located at the level of the adhesive tabs of the collar inserted into the upper mold 318. The Areas to which the adhesive is applied are indicated in different shapes, which is intended to express that there is a variety of design variations depending on the load profile of the trays.

Of course, hot or cold glue can be used or another heating system can be used.

After the cardboard frame of the tray has been completed, the tray in the forming station (FS) is lined with a gas-tight composite film attached in the stapling station.

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 next to one another and by means of a heating device 172 line the inside or surfaces of the trays 10 lying next to one another with the plastic composite film 134.

The tool of the molding station FS, which works according to the so-called skin method, 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 there are recesses in the upper and lower part 116, 118 shown, which are designed according to the recessed grips provided on the edge flanges.

The functioning of the FS forming station is briefly described below:

Is a series of erected carton blanks tightly against one another with their edge flanges in series, thus forming a saddle-shaped support, introduced via the pinned plastic film 134 (Heftungspunkte) in the forming station FS, so moves the previously after extended below Werkzeugunt ^'erteil 116 of the forming station 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).

At the same time, the continuous edge flanges 52 are heat-laminated over the entire surface.

Since the inner surfaces of the closely aligned cardboard blanks are now lined with the plastic composite film, the forming station FS is opened at the same time, which means that the plastic film connected connected trays are released and transported to be filled with the transport chain 148.

It is 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".

FIG. 5 (section along the edge flange 52 of a raw tray 10 with a composite film 134 lying thereon) shows the individual layers forming the composite film 134. The plastic composite film 134 has an oxygen barrier layer 136, a sealing layer 138, preferably made of peelable polyethylene, and an adhesive layer 137. It has been shown that the inner coating of the carrier material forming the food packaging can be made extremely thin. The film thickness is preferably in the range of the residual wall thicknesses in the base radii between 25 and 30 μm.

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

The trays which have been prefabricated in this way, after they have passed through the separating device 181, 182, can be nested and stacked and transported away for filling. In a second process, the trays can then be filled and sealed. A so-called tray sealer is a suitable device. The cover film is preferably also made of 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.

Because 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, 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.

Instead of cardboard, the blanks can of course also consist of other materials, such as cellulose, which also appear to be suitable, also with regard to their environmental compatibility.

Due to the internal 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.

Due to the subsequent sealing with the cover film over the peripheral flange, the cardboard cut an additional torsional stiffness or dimensional stability.

Of course, deviations from the variants shown are possible without departing from the basic idea of the invention.

Claims

Expectations

1. Tray for packaging, with a peripheral edge flange (52, 52a), which on the inside with a

Edge flange detecting plastic, in particular

Plastic composite film (134) can be lined, a prefabricated blank (10, 10b) covering the packaging base

(41), the side walls (43; 43b) and the edge flange (52; 52b) forms dadurc marked that on the

Folded edges (8a, 8b) are embossed on the side with grooves (53) on which the angle between the wall surfaces of the tray is greater than on the opposite side.

2. Tray according to claim 1, characterized in that the grooves (53) are formed only on folded edges (8a) between surface elements of the tray, which are provided at an angle to one another which is greater than a predetermined angle.

3. Tray according to claim 1 or 2, characterized in that the tray is formed from a blank (10b) with a bottom section and a plurality of wall sections running obliquely outwards, and the edge flange (52b) adjoining the wall sections, individual edge flange segments (54) Each edge section (52b) of the tray has an edge flange segment (54) and is shaped on the outside so that the edge flange segments (54) in the sealing position are flush with one another via miter cuts.

4. Tray according to claim 1 or 2, characterized in that the erected blank (10) consists of a prefabricated shell part (40) and an uninterrupted collar (52) placed thereon to form a tray which can be handled as a unit, wherein the collar (52) and the shell part (40) are each formed from a flat blank element.

5. Tray according to claim 3, characterized in that the tray is dimensionally stabilized in that it

Lining of an erected blank (10b) and in that the wall sections

(43b) outside the edge flange segments (52b)

Have side tabs (55) attached to the adjacent side wall portions (43b).

6. Tray according to claim 4, characterized in that the side walls (43) of the tray are stabilized by the edge flange (52), and in that the edge flange (52) has tabs (51) which are attached to the side walls (43) and the sections (43) of the shell part (40) forming the side walls (43) have side flaps (7a, 7b) which are fastened to the adjacent side wall sections (43).

7. Tray according to claim 5 or 6, characterized in that side flaps (55; 7a, 7b) are provided on each second side wall section (43).

8. Tray according to claim 6 or 6 and 7, characterized in that the tabs (51) of the edge flange

(52) and the side flaps (7a, 7b) are matched to one another so that they are in the assembled state of the

Do not overlap trays.

9. Tray according to one of claims 5-8, characterized in that all existing tabs (51) and side tabs (55; 7a, 7b) are fastened on the inside.

10. Tray according to claim 5, characterized in that the side flaps (55) are glued to the side walls (43b).

11. Tray according to one of claims 6-8, characterized in that the tabs (51) and the side tabs (7a, 7b) are glued to the side walls (43).

12. Tray according to claim 10 or 11, characterized in that the bonding is carried out with a temperature tape adhesive varnish 47.

13. Tray according to one of claims 1-12, characterized in that the blank (10, 10b) is formed from preferably multi-layer cardboard.

14. Tray according to claim 13, characterized in that the cardboard has a cover layer facing the outside of the packaging with a first surface structure which e.g. suitable as an information carrier, and has an inside second layer with a specific surface structure.

15. Tray according to claim 14, characterized in that the second layer preferably consists of recycled cardboard and is roughened on the inside.

16. Tray according to one of claims 1-15, characterized in that the plastic composite film (134) has an oxygen barrier layer (136), in particular made of polyvinyl alcohol (EVOH), and a sealing layer (138), preferably made of peelable polyethylene, and an adhesive layer (137 ), in particular from a modified polyethylene.

17. Tray according to claim 16, characterized in that the adhesive layer (137) consists of a copolymer of ethylene with 6% methacrylic acid, which are partially (50%) neutralized with Na or zinc ions (Surlyn A).

18. Tray, in particular according to one of claims 1-17, in which an erected blank (10, 10b) with bottom

(41), side walls (43, 43b) and edge flange (52, 52b) are lined on the inside with a plastic, in particular plastic composite film (134) which grips the edge flange, characterized in that the adhesive layer (137) made of ethylene ethacrylate with approx. 9 - There is 20% comonomer content, the comonomer content varies with the desired peeling force to be applied.

19. Tray, in particular according to one of claims 1-17, in which an erected blank (10, 10b) with bottom

(41), side walls (43, 43b) and edge flange (52, 52b) is lined on the inside with a plastic film, in particular a plastic composite film (134) that detects the edge flange, characterized in that the

Adhesive layer (137) made of acid-modified ethylene / acrylate

Polymer resins with medium to high acid-comonomer proportions and temperature-resistant ester additives, in particular from Bynel 2002.

20. Tray, in particular according to one of claims 1-19, in which an erected blank (10, 10b) with bottom (41), side walls (43, 43b) and edge flange (52, 52b) on the inside with a plastic flange which detects the edge flange , in particular plastic composite film (134), characterized in that the oxygen barrier layer (136) made of polyamide (PA) is mixed with amorphous nylon or polyamide resins, preferably Selar PA (20%).

21. Tray according to one of claims 16 - 20, characterized in that the oxygen barrier layer (136) of preferably 32% EVOH is mixed with preferably 15-20% of a thermoplastic ethylene / methacrylic (E / MAA) copolymer, the acid function of which partly with lithium ions has been neutralized, such as Surlyn 7928.

22. Tray for packaging, according to one of claims 16-21, characterized in that the plastic film has an initial thickness in the range between 100 and 150 μm, depending on the depth of the mold.

23. Food packaging characterized in that the filled interior of a tray according to one of claims 1 to 22 of the tray is sealed or sealed gas-tight, in particular oxygen-tight, via the edge flange.

24. A method for producing a tray according to one of claims 1-22, characterized in that it comprises the following method steps:

Embossing grooves in the at least one blank of the tray at the provided folding edges (8a), erecting the at least one blank, connecting, preferably gluing the at least one erected and shaped blank (10, 10b) into a tray (110),

Transport of the erected and nested trays (110) via a loading module to a forming station,

Lining the trays (110) with plastic composite film (134) in the molding station in a clock-controlled Lining process, the plastic composite film (134) running as in the inline process,

Removal of the trays (110) from the forming station to a separating device (181, 182), separating the trays (110) connected by the lining of the plastic composite film (134) by means of the separating device (181, 182), preferably by means of complete punchings.

25. A method for producing a tray according to claim 24, characterized in that the step of erecting the blank (10), the erection of the cutting unit of the shell part (40) in a first form (316), and the collar (52) by means of a second shape (318) is positioned exactly on the shell part (40), and in the method step of connecting, preferably gluing, the shell part (40) and the collar (52) are connected to a tray (110), preferably glued.

26. The method according to claim 24 or 25, wherein the bonding is carried out by activating an applied, temperature-dependent adhesive varnish, the mold used to erect the blank being heatable to activate the adhesive varnish.

27. The method according to any one of claims 24-26, wherein the lining of the inner surface of the tray is preferably done in rows and by means of a plastic composite film (134) covering the entire sealing surface of the edge flanges (52, 52b), which is arranged in a transfer station upstream of the molding station (FS) (US) is attached to the edge flanges (52, 52b) of the trays (110) (tacking points).

28. The method according to any one of claims 24-27, wherein the trays (110) are transported through the subsequent stations by means of the plastic film (134) forming the lining, which is gripped on the edge by grippers of a transport device, preferably a transport chain (148).

29. The method according to any one of claims 24-28, wherein the plastic composite film (134), if appropriate after heating, is molded into the trays (110) by producing a pressure difference and is heat-laminated with the relevant edge flange and the inside of the associated trays (110) ,

30. A method for filling and packaging a food packaging according to claim 23, which comprises a tray prefabricated in a method according to claims 27-33 according to claims 1-25, characterized in that the prefabricated trays cycle through a filling section (BS) which one Vacuuming and sealing station (VS) is connected downstream, where the trays (10) are preferably welded continuously in rows with a gas-tight cover film (120) over the edge of the flange.

31. Cutting element for a shell part, in particular as a shell part for a tray according to claims 1-16, which has a first surface with a smooth structure, which is suitable, for example, as an information carrier, and a second surface with a rough surface structure and first folded edges (8a) having, . which delimit an intended packaging base (41) so that the side sections (43) can be folded down to form the side wall, whereby triangular sections (7a, 7b) hang laterally on the side sections (43) via second fold edges (8b), characterized in that the fold edges

(8a, 8b) are grooved.

32. Cutting element according to claim 31, characterized in that only the first folded edges (8a) are grooved.

33. Cutting element according to claim 31 or 32, characterized in that the first surface is painted.

34. Cutting element according to one of claims 31, 32 or 33, characterized in that the triangular sections (7a, 7b) are coated on the first surface with a temperature-dependent adhesive varnish 47.

35. Cutting element for an uninterrupted collar which can be inserted into a shell part, in particular an uninterrupted collar for a tray according to claims 1-16, which has a first surface with a smooth structure which e.g. is suitable as an information carrier, and a second surface with a rough surface structure and around a punched-out central opening is formed in a ring shape and is rectangular on the outside with flattened corners, triangular or quadrangular sections on the inside via folded edges (8a)

(51) are spreadable, characterized in that the

Folded edges (8a) are grooved.

36. Cutting element according to claim 34, characterized in that the first surface is painted.

37. Cutting element according to claim .34 or 35, characterized in that the triangular sections (7a, 7b) are coated on the first surface with a temperature-dependent adhesive varnish 47.