METHOD FOR MANUFACTURING A CARDBOARD-PLASTIC COMPOSITE SHELL AND MANUFACTURING DEVICE

Description

State of the art

[0001] The invention relates to a method for producing a cardboard-plastic composite shell according to claim 1 and a manufacturing device according to claim 11.

[0002] Documents US 10,647,466 B2 and US 2020 / 0247571 A1 already proposed laminating a plastic film into a pre-folded cardboard box. To facilitate inserting the plastic film into the cardboard box and to ensure a smooth, bubble-free coating, the box features ventilation holes along its edges. These holes allow air trapped during the bonding process between the plastic film and the cardboard to escape or even be actively extracted. This requires specially designed molds with ventilation openings and specific cardboard cutting geometries.

[0003] Furthermore, methods for producing a cardboard-plastic composite shell are already known from EP0808774B1, DE 196 20 396 A1, DE 23 31 005 A1, DE 195 09 100 A1, US 3 917 155 A, CA 3 138 383 A1 and WO 00 / 75025 A1, wherein the already known methods include at least the following process steps: Providing a plastic film, pre-forming the plastic film to create a shell shape, providing a cardboard blank, joining the cardboard blank to the pre-formed plastic film to

[0004] Design of the cardboard-plastic composite tray, which forms a cup-shaped package for holding food. Likewise, manufacturing devices for producing cardboard-plastic composite trays according to known methods, as well as cardboard-plastic composite trays produced using these known methods, are already known. Disclosure of the invention

[0005] The invention relates to a method for producing a cardboard-plastic composite tray, in particular a MAP (Modified Atmosphere Packaging) cardboard-plastic composite tray for food, comprising at least the following process steps: a) providing a plastic film, b) pre-forming the plastic film to form a tray shape, c) providing a cardboard blank and d) joining the cardboard blank with the already pre-formed plastic film to form the cardboard-plastic composite tray.

[0006] It is proposed that the provided cardboard blank be unfolded or incompletely folded immediately before being bonded to the pre-formed plastic film. During the bonding process, the cardboard blank is folded onto the plastic film using a folding mechanism and / or a stamping mechanism. This advantageously allows for the simple, cost-effective, and / or rapid production of cardboard-plastic composite trays, particularly by eliminating the need to vent the cardboard box formed from the cardboard blank and / or to extract air from the cardboard box during production.

[0007] In particular, the cardboard-plastic composite tray consists essentially of two components: the cardboard blank and the plastic film. Specifically, the two components of the cardboard-plastic composite tray are bonded together over their entire surface, and preferably without any additional adhesives, for example, by press lamination. The cardboard blank is preferably made of recycled material (waste paper), virgin pulp, or groundwood. In the context of the invention described herein, the term "cardboard" is to be understood as encompassing all possible types of pulp and / or paper products (e.g., also cardboard or the like). Preferably, the cardboard of the cardboard blank has a basis weight between 300 g / m² and 500 g / m², more preferably 360 g / m². The cardboard blank is preferably free of adhesive flaps or the like.The cardboard blank is specifically designed to form a tray-shaped box and / or to be folded into a tray-shaped box. The tray-shaped box formed from the cardboard blank preferably constitutes a physical barrier against damage to the contents of the cardboard-plastic composite tray and / or against damage to a (gas and / or moisture) barrier layer formed by the plastic film. The tray-shaped box formed from the cardboard blank constitutes an outer surface of the cardboard-plastic composite tray. The plastic film forms an inner surface of the cardboard-plastic composite tray.A MAP (Modified Atmosphere Packaging) cardboard-plastic composite tray is understood to mean, in particular, a cardboard-plastic composite tray designed for use in a packaging process where a controlled change in the gas composition inside a gas-tight package is made during a closing process. Specifically, the cardboard-plastic composite tray can be completely sealed gas-tight / airtight by applying a gas-tight / airtight lid.

[0008] In particular, the plastic film is provided in a flat form in step a). Preferably, a plastic film is understood to be a thin sheet of plastic, which is initially manufactured in continuous webs, rolled up, and later cut into suitable pieces. Preferably, the plastic film has a thickness between 40 µm and 100 µm, more preferably 60 µm. In particular, the plastic film has a sealability so that the cardboard-plastic composite tray can be closed and / or sealed after filling (e.g., with a cover film). Preferably, the plastic film is stretchable, preferably stretchable by at least 50% without damage or tearing. Preferably, the plastic film is made of a plastic with a high barrier effect against water vapor, oxygen, nitrogen, and / or other gaseous substances.For example, the plastic film is made of polyethylene (PE / LDPE), in particular PE with an ethylene-vinyl alcohol copolymer (EVOH) separating layer, or polypropylene (PP). It is also conceivable that the plastic film is made of a biodegradable plastic material. In particular, the plastic film is a single layer. Preferably, the plastic film is not a composite film made of several different plastics, especially plastics of different classes. However, it is conceivable that the plastic film is a composite film whose components belong to a common class of plastic, which are in particular recyclable together, i.e., a composite film made of layers of different PE plastic types. In particular, during the supply process, a flat sheet of plastic film is unwound from a roll and clamped into a frame.In particular, the area of ​​the plastic film web arranged within the frame is deformed during pre-forming. Specifically, pre-forming takes place before the plastic film is brought together with the cardboard blank. Specifically, the plastic film is first pre-formed and then brought into contact with the (unfolded or only partially folded) cardboard blank. A tray shape is understood to mean, in particular, any shape that has a base and side walls extending from the base and circumferentially extending 360° to form a receiving space. In connection with the invention described herein, bowl shapes, plates, cup shapes, and other container shapes with an access opening are also understood to be tray shapes according to the invention.Preferably, the side walls of the tray form have a height of at least 5%, preferably at least 10%, or preferably at least 20% of the width or depth of the tray form's base. In particular, the length of the shortest side edge of the smallest geometric cuboid that just completely encloses the finished cardboard-plastic composite tray is at least 5%, preferably at least 10%, or preferably at least 20% of the length of the longest side edge of the smallest geometric cuboid that just completely encloses the finished cardboard-plastic composite tray.

[0009] In particular, the cardboard blank is provided in a flat form. Specifically, the cardboard blank is designed such that, after folding, it forms a shell shape which preferably corresponds at least substantially to the pre-formed plastic film on at least one inner surface. In particular, at least a section of the cardboard blank is bonded to the plastic film before the cardboard blank is completely folded / before the cardboard blank is folded into its final shape. "Provided for" is understood to mean, in particular, specifically programmed, designed, and / or equipped. The fact that an object is intended for a specific function is understood to mean, in particular, that the object fulfills and / or performs this specific function in at least one application and / or operating state.

[0010] Furthermore, it is proposed that the cardboard blank be bonded to the plastic film in such a way that the plastic film and cardboard blank can be separated manually, and in particular, in a recyclable manner. This advantageously achieves a high level of environmental compatibility. In particular, the plastic film can be peeled off the cardboard (manually). Preferably, the plastic film can be separated / peeled off the cardboard blank in such a way that, after separation of the plastic film and cardboard, the cardboard is at least substantially free of film residue and the plastic film is at least substantially free of cardboard residue. This advantageously achieves a high level of recyclability of the cardboard-plastic composite tray. Preferably, the cardboard blank and the plastic film are bonded together without any additional adhesives to enable manual separation.In particular, the plastic film of the finished cardboard-plastic composite tray has at least one flap or overhang which can be used to peel the plastic film off the cardboard of the cardboard blank.

[0011] Furthermore, it is proposed that the plastic film be bonded to the cardboard blank by lamination. This advantageously achieves good separability between the plastic film and cardboard, thus ensuring high recyclability and / or environmental compatibility. Additionally, a simple and, preferably, adhesive-free manufacturing process can be advantageously achieved. In particular, the plastic film is bonded to the cardboard blank by hot lamination and / or pressure lamination, preferably by a combination of hot and pressure lamination. "Laminating" is understood to mean, in particular, a material-bonded joining process, preferably thermal and / or pressure-induced, which requires no auxiliary materials such as adhesives or similar substances.As an alternative to hot or pressure lamination, and / or as an alternative to a combination of hot and pressure lamination, it is also conceivable to bond the plastic film to the cardboard of the cardboard blank by cold lamination. Preferably, particularly in cold lamination, a cold-sealing medium is applied to the plastic film and / or to the cardboard of the cardboard blank in at least one process step. More preferably, in at least one process step, particularly in cold lamination, after the application of the cold-sealing medium, the plastic film and the cardboard of the cardboard blank are bonded by pressing them together, in particular by pressing them against each other. By using a cold-sealing medium, a special heat-seal layer on the plastic film can advantageously be omitted.It is advantageous to achieve a high degree of independence from the temperature windows during which the plastic film is deformed and / or during which a heat-sealing process takes place. It is also advantageous to achieve a high degree of independence from the type of plastic film to be bonded and the surface of the cardboard blank, so that a wide variety of cardboard types can be used for the process, especially since, for example, a plastic film intended for hot lamination behaves differently on coarse grey cardboard than on cardboard with a coated / varnished / printed surface.

[0012] Furthermore, it is proposed that the dimensional stability of the cardboard-plastic composite shell is achieved by laminating the plastic film to the cardboard blank. This advantageously allows for a simple and, preferably, adhesive-free manufacturing process that is environmentally friendly. Moreover, overall material consumption can be kept low, thereby reducing costs. In particular, the plastic film holds the individual side walls of the cardboard blank in their intended folded position.

[0013] Furthermore, it is proposed that during pre-forming, the plastic film is shaped, in particular drawn, into a form that corresponds at least substantially to the desired internal shape of the cardboard-plastic composite shell. This advantageously enables simple, cost-effective, and / or rapid production of cardboard-plastic composite shells. Specifically, during pre-forming, a forming tool designed as a stamp is pressed into the frame that holds the plastic film.

[0014] Heating the plastic film during or immediately before pre-forming can advantageously optimize the pre-forming process. In particular, this increases the plasticity of the film. Specifically, the plastic film is heated to temperatures between 80°C and 170°C during the pre-forming process.

[0015] It is further proposed that, when joining the cardboard blank to the pre-formed plastic film, a section of the cardboard blank intended for forming the base of the cardboard-plastic composite tray should be joined to the plastic film before a section intended for forming a side wall of the cardboard-plastic composite tray. This advantageously allows for simple, cost-effective, and / or rapid production of cardboard-plastic composite trays, particularly by eliminating the need to vent the cardboard box formed from the cardboard blank and / or to extract air from the cardboard box during production.

[0016] Advantageously, during the folding process, the air escapes between the plastic film and the cardboard of the cardboard blank without the need for aids or ventilation holes.

[0017] If, according to the invention, the cardboard blank is folded onto the pre-formed plastic film by means of a folding mechanism and / or a stamping mechanism during the joining process, a simple, cost-effective, and / or rapid production of cardboard-plastic composite shells can be advantageously achieved, in which, in particular, the air between the plastic film and the cardboard of the blank escapes without additional aids or ventilation holes during the folding process. Specifically, when the cardboard blank is folded onto the pre-formed plastic film, the sections of the cardboard blank intended for forming the side walls of the cardboard-plastic composite shell are folded out of the plane of the section of the cardboard blank intended for forming the bottom of the cardboard-plastic composite shell.

[0018] Furthermore, if, particularly when joining the cardboard blank to the pre-formed plastic film, the cardboard blank is folded in such a way that it remains free of overlaps and / or overlaps with itself and with other cardboard blanks, a particularly low resource consumption can be achieved. In addition, this advantageously creates a flat sealing surface onto which a cover film or similar material can be tightly applied.

[0019] In this context, it is proposed that when folding the cardboard blank, a flat and / or seamless sealing edge is created, particularly around an opening of the finished cardboard-plastic composite tray. This allows the cardboard-plastic composite tray to be advantageously sealed tightly. Specifically, the opening of the tray is positioned opposite the base of the cardboard-plastic composite tray. In particular, the sealing edge of the finished cardboard blank, preferably a sealing plane of the sealing edge of the finished cardboard blank, runs at least substantially parallel to the base of the finished cardboard blank, especially the cardboard-plastic composite tray. Specifically, after filling, the cardboard-plastic composite tray is sealed by applying the cover film and heat-welding the cover film to the plastic film in the area of ​​the sealing edge.The cover film can be made of a plastic material that is identical to or different from the plastic film.

[0020] Furthermore, it is proposed that at least the joining of the cardboard blank to the plastic film and / or at least the creation of a box from the cardboard blank, preferably all process steps of the method for manufacturing the cardboard-plastic composite tray, proceed completely without the application of additional adhesives. This advantageously enables the simple, cost-effective, and / or rapid production of cardboard-plastic composite trays, which, in particular, possess especially good recycling properties due to the easy separation of the plastic film and cardboard after use. In this context, an adhesive is understood to be a process material different from and / or separately formed from the plastic film and the cardboard, which is used in the bonding process to join different materials.The use of adhesive or self-adhesive plastic films, for example, is not considered the use of adhesives in this context. Similarly, the partial melting of plastic films during lamination is not considered the use of adhesives in this context.

[0021] Furthermore, a manufacturing device for producing cardboard-plastic composite shells from at least one plastic film and one cardboard blank is described, comprising a method according to the invention comprising pre-forming the plastic film and subsequently joining the plastic film to the cardboard blank, comprising a film pre-forming unit and a pressing device with a punch mechanism, wherein the film pre-forming unit comprises at least one punch tool with an outer contour that corresponds at least substantially to an inner contour to be achieved of the finished cardboard-plastic composite shell, wherein the punch mechanism comprises a further punch tool designed to complement the punch tool, which is provided for folding and laminating in a common operation step, and / or comprising a film pre-forming unit and a pressing device with a folding mechanism.The folding mechanism is designed to fold the cardboard blank for forming and laminating side walls by pressing the side wall sections of the cardboard blank onto the pre-formed plastic film. This advantageously enables simple, cost-effective, and / or rapid production of cardboard-plastic composite shells. Furthermore, it eliminates the need for venting or extracting air from the cardboard box during production. The film pre-forming unit is specifically designed to pre-deform the initially flat plastic film before bonding it to the cardboard blank.

[0022] According to the invention, it is proposed that the film preforming unit comprises at least one die with an outer contour that corresponds at least substantially to an inner contour to be achieved in the finished cardboard-plastic composite shell, wherein the die mechanism includes a further die complementary to the die, which is designed to fold and laminate in a single operation. This enables effective, cost-efficient, and / or simple plastic preforming of the plastic film. In particular, the film preforming unit includes the frame that clamps the plastic film flat, into which the die is pressed during the preforming process.In particular, it is conceivable that the stamping tool has venting and / or vacuuming channels, which are preferably designed to ensure a close fit of the plastic film to the stamping tool, at least in a joining process following the pre-forming process, in which the plastic film is laminated onto the cardboard of the cardboard blank.

[0023] Additionally, it is proposed that the film preforming unit include at least one heating device for warming the plastic film before and / or during preforming. This enables an efficient, cost-effective, and / or simple manufacturing process, particularly by improving the plastic preformability of the film. Advantageously, heating the plastic film before and / or during preforming can also increase its elongation.

[0024] If the heating device is at least partially integrated with the punch tool of the film preforming unit, effective heat transfer during the preforming process can be advantageously ensured. Alternatively or additionally, the heating device can have one or more further heating elements and / or heating devices that are separate from the punch tool. In particular, these heating elements and / or heating devices can be designed to apply a hot air stream and / or heat radiation to the plastic film, especially with the aim of heating the plastic film before and / or during the preforming process.

[0025] Furthermore, a cardboard-plastic composite shell is proposed, which is produced using the inventive method and / or the inventive manufacturing device. This advantageously allows for the procurement of a particularly cost-effective and / or simple and / or quick-to-produce cardboard-plastic composite shell.

[0026] Furthermore, a cardboard-plastic composite tray is proposed, comprising a plastic film and a cardboard blank folded into a box. At least one inner surface of the box, forming a storage area, is completely lined with the plastic film in such a way that the plastic film is bonded to the folded cardboard blank over its entire surface, and in particular without any additional adhesive. The box folded from the cardboard blank (in contrast to the previously cited known cardboard-plastic composite trays) is, at least in its corner areas, essentially gap-free. This advantageously allows for the provision of a particularly cost-effective and / or easily and / or quickly manufactured cardboard-plastic composite tray. The cardboard-plastic composite tray is advantageously free of gaps in the cardboard that could create weak points, e.g., in the corner areas of the box.This advantageously allows for better protection of products stored in the box, such as perishable foodstuffs. Preferably, the cardboard-plastic composite tray is completely free of gaps, except for the tray opening. The term "free of gaps" refers specifically to gaps between adjacent side walls and / or to creases, grooves, slots, and / or perforations. The box comprises a base and side walls. Preferably, the box is rectangular. However, other polygonal and / or partially rounded shapes are also conceivable. The box is open on one side, particularly through the tray opening. The plastic film lining is also completely gap-free and at least liquid-tight, preferably gas-tight.A corner area is understood to be, in particular, an area of ​​the box where two side edges of folded side walls and the base of the box meet. Specifically, the cardboard blank is free of ventilation elements that, during the manufacture of the cardboard-plastic composite tray, are intended to allow air to escape and / or be drawn out from a space between the plastic film and the cardboard blank. However, it is also conceivable that the cardboard blank has other gaps or recesses, particularly those located away from the corner areas, the primary purpose of which is to form a viewing window to allow a view into the interior of the cardboard-plastic composite tray.

[0027] Furthermore, it is proposed that, in order to achieve advantageously low resource consumption, the cardboard blank folded to form the box is free from overlaps and / or overlaps with itself or with parts of other cardboard blanks, and / or that, in order to advantageously optimize the recyclability of the cardboard-plastic composite tray, the plastic film and the cardboard of the cardboard blank are connected in such a way that simple manual separation of the plastic film and cardboard is possible, allowing the plastic film and cardboard to be fed into different recycling streams.

[0028] Furthermore, it is proposed that, to advantageously enable a tight seal, the cardboard blank folded to form the box should create a flat and / or seamless sealing edge around an opening of the box, particularly the tray opening. In this case, it is also proposed that the sealing edge be covered by the plastic film, at least to a large extent, preferably completely. This ensures a particularly good seal and / or allows for simple (purely thermal) sealing. In particular, the lining of the box extends beyond the inside of the box and over the sealing edge.

[0029] Furthermore, it is proposed that the cardboard blank folded to form the box be largely, and preferably completely, free of any covering by a plastic film or the like on an outer surface opposite the inner side, particularly opposite the storage area. This advantageously reduces resource consumption, especially the amount of plastic used, and thus also manufacturing costs. Drawings

[0030] Further advantages become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination.

[0031] They show: Fig. 1 a schematic perspective view of a cardboard-plastic composite shell formed from a plastic film and a cardboard blank, Fig. 2 a schematic top view of the cardboard blank in unfolded form, Fig. 3 a schematic representation of a manufacturing device for producing the cardboard-plastic composite shell during a work step, Fig. 4 a schematic representation of the manufacturing device during a first further work step, Fig. 5 a schematic representation of the manufacturing device during a second further work step, Fig. 6 a schematic representation of the manufacturing device during a third further work step, Fig. 7a a schematic representation of the manufacturing device during a first partial work step of a fourth further work step, Fig.Fig. 7 shows a schematic representation of the manufacturing device during a second sub-step of the fourth further work step, Fig. 8 shows a schematic representation of the manufacturing device during an alternative fourth further work step, and Fig. 9 shows a schematic flowchart of a process for manufacturing the cardboard-plastic composite shell. Description of the exemplary implementations

[0032] The Fig. 1 Figure 1 shows a schematic perspective view of a cardboard-plastic composite tray 10. The cardboard-plastic composite tray 10 is designed as a MAP cardboard-plastic composite tray for food. The cardboard-plastic composite tray 10 includes a plastic film 12. The cardboard-plastic composite tray 10 includes a cardboard blank 16 (see also Fig. 2Preferably, the cardboard-plastic composite tray 10 consists only of the cardboard blank 16 and the plastic film 12, and, when closed, optionally a cover film (not shown). The cardboard blank 16 is folded into a box 30. The box 30 / the cardboard-plastic composite tray 10 forms a storage area 40 on an inner surface 44. The box 30 / the cardboard-plastic composite tray 10 is intended, for example, for storing foodstuffs such as meat, cheese, etc. Of course, the storage area 40 can also be used to store other objects. Preferably, the materials of at least the plastic film 12 and / or the cover film, but optionally also of the cardboard blank 16, are adapted to the object to be stored and the respective storage requirements of that object.The plastic film 12 provides the barrier properties required depending on the stored object and can therefore be equipped with different adapted chemical-physical properties. The plastic film 12 is stretchable. The plastic film 12 is sealable, so that the finished cardboard-plastic composite tray 10 can be closed with the cover film. The inner surface 44 of the box 30 / the cardboard-plastic composite tray 10 forms the storage area 40. The storage area 40 is designed to hold the object. The cardboard-plastic composite tray 10 has a tray opening 26. Objects can be placed into and / or removed from the cardboard-plastic composite tray 10 through the tray opening 26. The storage area 40 / the tray opening 26 can be hermetically sealed / locked all around by means of the cover film.

[0033] Storage area 40 of box 30 is completely lined with the plastic film 12. The plastic film 12 is lined in such a way that it is bonded to the cardboard of the cardboard blank 16 folded to form box 30. The plastic film 12 and the cardboard of the cardboard blank 16 are bonded together in such a way that the plastic film 12 and the cardboard can be easily separated manually for feeding into different recycling streams. The cardboard-plastic composite tray 10 has a handle 48. The handle 48 is integral with the plastic film 12. The handle 48 provides a point of engagement for the plastic film 12, allowing it to be peeled away from the cardboard of the cardboard blank 16.

[0034] The box 30, folded from the cardboard blank 16, is gap-free in the corner areas 42 of the box 30. The box 30, folded from the cardboard blank 16, is gap-free except for the opening 26 of the cardboard-plastic composite tray 10.

[0035] The cardboard blank 16, folded to form box 30, is free from overlaps and / or overlaps with itself. The cardboard blank 16, folded to form box 30, is free from overlaps and / or overlaps with parts of other cardboard blanks 16. The cardboard blank 16, folded to form box 30, has a sealing edge 28. The sealing edge 28 is designed for attaching the cover film. The sealing edge 28 completely surrounds an opening of the box 30 / the tray opening 26. The sealing edge 28 is flat. The sealing edge 28 is seamless. The sealing edge 28, like the inner surface 44 of the box 30, is completely covered by the plastic film 12. The cardboard blank 16, folded to form box 30, has an outer surface 46. The outer surface 46 of the cardboard blank 16, folded to form box 30, is opposite the inner surface 44. The outer surface 46 of the cardboard blank 16, folded to form box 30, is opposite the storage area 40.The outer surface 46 is free from any covering by the plastic film 12 or by another plastic film 12. The dimensional stability of the cardboard-plastic composite shell 10 is generated at least predominantly by the plastic film 12, which is bonded to the cardboard blank 16 by lamination. The cardboard of the cardboard blank 16 serves primarily to reinforce impact protection / mechanical protection of the cardboard-plastic composite shell 10 and / or to reduce the amount of plastic material required for the cardboard-plastic composite shell 10.

[0036] The Fig. 2Figure 1 shows the cardboard blank 16 in its unfolded state. The cardboard blank 16 has a section 50 designed to form the base 18 of the box 30 / the cardboard-plastic composite tray 10. The cardboard blank 16 has further sections 52 designed to form the side walls 20 of the box 30 / the cardboard-plastic composite tray 10. When the box 30 is folded from the cardboard blank 16, the further sections 52 are folded out of the plane of section 50 (upwards). The side walls 20 of the box 30 / the cardboard-plastic composite tray 10 are inclined or perpendicular to the base 18 of the box 30. The angle 64 between a side wall 20 of the box 30 and the base 18 of the box 30 is less than 150°, preferably less than 120°. The sub-areas 52, which are intended to form the side walls 20 of the box 30 / the cardboard-plastic composite shell 10, have side edges 54, 56.The side edges 54, 56 of the sub-areas 52 forming the side walls 20 are free of adhesive tabs. Opposite side edges 54, 56 of the sub-areas 52 forming the side walls 20 touch when the cardboard blank 16 is folded to form the box 30. The opposite side edges 54, 56 of the sub-areas 52 forming the side walls 20 touch when the cardboard blank 16 is folded to form the box 30, without overlapping each other. The cardboard blank 16 has additional sub-areas 58 which are intended to form the sealing edge 28 of the box 30 / the cardboard-plastic composite tray 10. The sub-areas 58, which are intended to form parts of the sealing edge 28 of the box 30 / the cardboard-plastic composite tray 10, have side edges 60, 62. The side edges 60, 62 of the sub-areas 58 forming the sealing edge 28 are free of adhesive tabs.Opposite side edges 60, 62 of the sections 58 forming the sealing edge 28 touch when the cardboard blank 16 is folded into the box 30. These opposite side edges 60, 62 of the sections 58 forming the sealing edge 28 touch when the cardboard blank 16 is folded into the box 30, without overlapping each other. When the cardboard blank 16 is folded into the box 30, the sections 58 forming the sealing edge 28 are folded away from the side walls 20. When the cardboard blank 16 is folded into the box 30, the sections 58 forming the sealing edge 28 lie in a common plane. The plane in which the sub-areas 58 of the cardboard blank 16, which form the sealing edge 28 and are folded to form the box 30, lie runs parallel to the sub-area 50 of the cardboard blank 16, which forms the bottom 18 of the box 30.

[0037] The Figures 3 to 8Figure 3 shows schematically and step-by-step a method for producing the cardboard-plastic composite shell 10 using a manufacturing device 32. The manufacturing device 32 is designed to carry out the method according to the invention. The manufacturing device 32 performs a process for producing the cardboard-plastic composite shells 10 from a plastic film 12 and a cardboard blank 16. This process includes at least one pre-forming step 66, in which the plastic film 12 is pre-formed, and at least one joining step 68, in which the plastic film 12 is subsequently joined to the cardboard blank 16 following the pre-forming step 66. Fig. 1 Figure 1 shows the finished cardboard-plastic composite shell 10 produced by means of the manufacturing device 32. The manufacturing device 32 has a film pre-forming unit 34 (see above). Figs. 4 and 5The film pre-forming unit 34 is designed to process a film web that is initially provided flat (see...). Fig. 3The film preforming unit 34 is designed to preform the plastic film 12 in such a way that a preform is achieved that approximately corresponds to the desired inner contour of the finished cardboard-plastic composite shell 10. The film preforming unit 34 includes a punch tool 36 for this purpose. The punch tool 36 is designed as a lower punch. The punch tool 36 has an outer contour that corresponds at least substantially to the desired inner contour of the finished cardboard-plastic composite shell 10. The film preforming unit 34 includes a frame 70, in particular a punch frame. The frame 70 is designed to clamp a portion of the plastic film web 12 firmly and flat before the preforming step 66 is carried out. The punch tool 36 is designed to produce a preform by pressing the plastic film 12 clamped in the frame 70, which roughly corresponds to the desired inner contour of the finished cardboard-plastic composite shell 10.

[0038] The film preforming unit 34 has at least one heating device 38. The heating device 38 is used to heat the plastic film 12 before preforming the plastic film 12 (see Fig. 4 ) and / or during the pre-forming of the plastic film 12 (see Fig. 5 ) provided. The heating device 38 has a first heating unit 72 (see Fig. 4The first heating unit 72 is designed as a separate heating unit 72 from the punch tool 36. The first heating unit 72 is at least intended to heat the plastic film 12 before pre-forming. The first heating unit 72 can alternatively or additionally be intended to heat the plastic film 12 during pre-forming. The first heating unit 72 has a heating fan or a radiant heater. The first heating unit 72 is intended to apply a heated airflow or heat radiation to the film. Alternatively or additionally, the first heating unit 72 can also be intended to heat the punch tool 36, in particular a surface of the punch tool 36. The heating device 38 has a second heating unit 74 (see Fig. 5The second heating unit 74 is at least partially formed integrally with the punch tool 36. The punch tool 36 has an internal heating source, for example, a heating coil. The second heating unit 74 is at least intended to heat the plastic film 12 during pre-forming. The second heating unit 74 is intended to heat the punch tool 36, in particular a surface of the punch tool 36. It is conceivable that the heating device 38 comprises only the first heating unit 72 or only the second heating unit 74. In the Figures 5 to 8 The subsequent manufacturing steps are shown as an example using only the second heating unit 74. Alternatively or additionally, the first heating unit 72 could also be used in the manufacturing steps of the Figures 5 to 8 be used.

[0039] The manufacturing device 32 has a pressing device 76 (see Figs. 7a to 8The pressing device 76 is designed to press the cardboard blank 16 onto the pre-formed plastic film 12. The punching tool 36 forms a counterpart that resists the pressing force of the pressing device 76. The pressing device 76 is initially pressed onto the punching tool 36 from a direction opposite to the punching movement of the punching tool 36, while the plastic film 12 and the unfolded or only partially folded cardboard blank 16 are positioned between the punching tool 36 and the pressing device 76. By pressing the cardboard blank 16 onto the plastic film 12 and, if necessary, simultaneously heating the plastic film 12, the plastic film 12 is laminated onto the cardboard blank 16. During the pressing process of the pressing device 76, the punching tool 36 remains stationary. In the exemplary embodiment from the Figures 7a and 7bFirst, the base 18 of the cardboard blank 16 is laminated, and then the side walls 20. In the alternative embodiment of the Fig. 8 In contrast, the base 18 and side walls 20 of the cardboard blank 16 are laminated simultaneously.

[0040] The in the Figures 7a and 7bThe illustrated manufacturing device 32 has a pressing device 76 with a folding mechanism 22. The folding mechanism 22 is designed to fold the cardboard blank 16. Specifically, it is designed to fold the cardboard blank 16 to form and laminate the side walls 20. The folding mechanism 22 presses the sections 52 of the cardboard blank 16 forming the side walls 20 onto the pre-formed plastic film 12. Additionally, it is conceivable that the stamping tool 36 has a suction mechanism 78, which is designed to draw the plastic film 12 onto the stamping tool 36, at least in the areas forming the side walls 20. This allows for advantageous optimization of the lamination of the side walls 20, in particular by preventing air bubbles or similar from forming between the plastic film 12 and the stamping tool 36 during lamination.

[0041] The one in Figure 8The illustrated manufacturing device 32 has a press device 76 with a punch mechanism 24 (instead of the folding mechanism 22 from the Figures 7a and 7b The stamping mechanism 24 comprises a further stamping tool 80 designed to complement the stamping tool 36. The further stamping tool 80 is designed as an upper stamp. The further stamping tool 80 is pressed onto the cardboard blank 16, which is placed on the pre-formed plastic film 12, from a direction opposite to the direction in which the stamping tool 36 moves during the pre-forming of the plastic film 12. The further stamping tool 80 folds and laminates in a single operation.

[0042] The Fig. 9 Figure 10 shows a schematic flowchart of a process for manufacturing the cardboard-plastic composite shell. Fig. 1Figure 1 shows the finished cardboard-plastic composite tray 10 produced using the described method. In at least one process step 82, a web of the plastic film 12 is spread out flat, e.g., unrolled. In process step 82, the plastic film 12 is provided. In at least one further process step 84, a section of the web of the plastic film 12 is clamped into the frame 70 (see also Fig. 3 In at least one further (optional) process step 86, at least the section of the plastic film 12 clamped in the frame 70 is heated, e.g., by the first heating unit 72. In process step 86, the plastic film 12 is heated immediately before pre-forming. In pre-forming step 66, the punch tool 36 is pressed into the frame 70 (see also Figs. 4 and 5The plastic film 12 is pre-formed. The die 36 can be heated, for example, by the second heating unit 74. In the pre-forming step 66, the plastic film 12 is heated during pre-forming. However, depending on the chemical and physical properties of the plastic film 12, it is also conceivable that heating during pre-forming can be omitted entirely. In the pre-forming step 66, the plastic film 12 is pre-formed into the shell shape 14, which preferably already closely resembles the shape of the inner surface 44 of the cardboard-plastic composite shell 10. Optionally, the plastic film 12 is drawn laterally against the die 36 during the pre-forming step 66 (see also Fig. 7a In the pre-deformation step 66, the plastic film 12 is pre-deformed to form the shell shape 14.

[0043] In a further process step 88, the cardboard blank 16 is placed onto the pre-formed plastic film 12. In process step 88, the cardboard blank 16 is provided. The cardboard blank 16 provided in process step 88 is unfolded or incompletely folded immediately before being bonded to the pre-formed plastic film 12. The cardboard blank 16 is placed on the plastic film 12 on a side opposite the stamping tool 36 (see also Fig. 6In the subsequent joining step 68, the plastic film 12 is laminated onto the cardboard blank 16. In joining step 68, the cardboard blank 16 is joined to the pre-formed plastic film 12 to form the cardboard-plastic composite shell 10. In joining step 68, the cardboard blank 16 is joined to the plastic film 12 in such a way that the plastic film 12 and the cardboard blank 16 can be separated manually. In joining step 68, the cardboard blank 16 is joined to the plastic film 12 in such a way that the plastic film 12 and the cardboard blank 16 can be separated for recycling. The joining of the cardboard blank 16 to the plastic film 12, in particular joining step 68, is completely adhesive-free, i.e., in particular, completely free of the application of any additional adhesive.

[0044] When performing connection step 68 with the one in the Figures 7a and 7bIn the folding mechanism 22 shown, when connecting the cardboard blank 16 with the pre-formed plastic film 12, the section 50 of the cardboard blank 16 intended to form the base 18 of the cardboard-plastic composite shell 10 is joined in a first joining step 90. This first joining step precedes a second joining step 92, in which the further sections 52 of the cardboard blank 16 intended to form the side walls 20 of the cardboard-plastic composite shell 10 are joined to the plastic film 12. In this joining step 68, the cardboard blank 16 is folded onto the plastic film 12 by means of the folding mechanism 22. The cardboard blank 16 is folded in such a way that the folded cardboard blank 16 remains free of overlaps and / or overlaps with itself and with other cardboard blanks.Furthermore, in joining step 68, and in particular in the second joining sub-step 92, the cardboard blank 16 is folded in such a way that a flat and seamless sealing edge 28 is created around the opening 26 of the finished cardboard-plastic composite tray 10. Folding the cardboard blank 16 in joining step 68 creates the box 30. The creation of the box 30 from the cardboard blank 16 is entirely adhesive-free. The creation of the box 30 from the cardboard blank 16 occurs completely without the use or application of any additional adhesives.

[0045] Alternatively, instead of connection step 68, which uses the folding mechanism 22, an alternative connection step 94 can be performed that does not require a folding mechanism 22. In the alternative connection step 94, when connecting the cardboard blank 16 with the pre-formed plastic film 12, the cardboard blank 16 is folded onto the plastic film 12 / folded into the box 30 by means of the stamping mechanism 24 and simultaneously connected to the plastic film 12 in the same step (see also Fig. 8 In the alternative joining step 94, the layered plastic films 12 and cardboard blanks 16 are pressed together between two complementary stamping tools 36, 80, wherein the plastic film 12 has already been pre-deformed before pressing with the cardboard blank 16 and wherein preferably the stamping tool 36 in contact with the plastic film 12 is heated.

[0046] In at least one further process step 96, the finished cardboard-plastic composite tray 10 is removed from the manufacturing device 32. The unsealed cardboard-plastic composite tray 10 can be stacked with other unsealed cardboard-plastic composite trays 10. In at least one further process step 98, the finished cardboard-plastic composite trays 10 are fed to a filling line, where the storage area 40 of the cardboard-plastic composite trays 10 is filled with objects. In at least one further process step 100, the filled cardboard-plastic composite trays 10 are fed to a sealing line, where the storage area 40 of the filled cardboard-plastic composite trays 10 is sealed by the cover film, in particular gas-tight.Before closing the filled cardboard-plastic composite trays 10, the air remaining in the cardboard-plastic composite trays 10 can be replaced by a gas, in particular an inert gas / protective gas such as nitrogen or similar.

Claims

1. Method for producing a cardboard-plastics composite tray (10), in particular a MAP cardboard-plastics composite tray for food, comprising at least the following method steps (66, 68, 82, 88): - providing a plastics film (12), - pre-forming the plastics film (12) to form a tray shape (14), - providing a cardboard blank (16), - bonding the cardboard blank (16) to the already pre-formed plastics film (12) to form the cardboard-plastics composite tray (10), characterized in that the cardboard blank (16) provided is not folded or is incompletely folded immediately before being bonded to the pre-formed plastics film (12), when the cardboard blank (16) is bonded to the pre-formed plastics film (12), the cardboard blank (16) being folded onto the plastics film (12) by means of a folding mechanism (22) and / or by means of a stamping mechanism (24).

2. Method according to claim 1, characterized in that the cardboard blank (16) is bonded to the plastics film (12) in such a way that the plastics film (12) and the cardboard blank (16) can be separated manually and, in particular, such that they can be recycled.

3. Method according to claim 1 or 2, characterized in that the plastics film (12) is bonded to the cardboard blank (16) by lamination.

4. Method according to claim 3, characterized in that a dimensional stability of the cardboard-plastics composite tray (10) is created by the plastics film (12) bonded to the cardboard blank (16) by lamination.

5. Method according to any of the preceding claims, characterized in that the plastics film (12) is brought, in particular drawn, into a shape during the pre-forming process which at least substantially corresponds to an inner shape to be attained of the cardboard-plastics composite tray (10).

6. Method according to any of the preceding claims, characterized in that the plastics film (12) is heated during the pre-forming process or immediately before the pre-forming process.

7. Method according to any of the preceding claims, characterized in that when the cardboard blank (16) is bonded to the pre-formed plastics film (12), a partial region (50) of the cardboard blank (16), which is intended to form a base (18) of the cardboard-plastics composite tray (10), is bonded to the plastics film (12) before a further partial region (52) of the cardboard blank (16) which is intended to form a side wall (20) of the cardboard-plastics composite tray (10).

8. Method according to any of the preceding claims, characterized in that, in particular when the cardboard blank (16) is bonded to the pre-formed plastics film (12), the cardboard blank (16) is folded in such a way that the folded cardboard blank (16) remains free of intersections and / or overlaps with itself and with other cardboard blanks.

9. Method according to any of the preceding claims, characterized in that when the cardboard blank (16) is folded, a sealing edge (28) is created which is planar and / or free of layer jumps, and which in particular extends around a tray opening (26) of the finished cardboard-plastics composite tray (10).

10. Method according to any of the preceding claims, characterized in that at least the bonding of the cardboard blank (16) to the plastics film (12) and / or at least the creation of a box (30) from the cardboard blank (16) takes place completely free of the application of additional adhesives.

11. Production device (32) for producing cardboard-plastics composite trays (10) at least from one plastics film (12) and one cardboard blank (16) each by means of a method according to any of the preceding claims, which method comprises pre-forming of the plastics film (12) and subsequent bonding of the plastics film (12) to the cardboard blank (16), the production device comprising a film pre-forming unit (34) and a pressing device (76) with a stamping mechanism (24), wherein the film pre-forming unit (34) has at least one stamping tool (36) having an outer contour that at least substantially corresponds to an inner contour to be attained of the finished cardboard-plastics composite tray (10), wherein the stamping mechanism (24) has a further stamping tool (80) which is complementary to the stamping tool (36) and is intended to fold and laminate in a common work step, and / or comprising a film pre-forming unit (34) and a pressing device (76) with a folding mechanism (22), wherein the folding mechanism (22) is intended to fold the cardboard blank (16) for forming and laminating side walls (20) by the folding mechanism (22) pressing partial regions (52) of the cardboard blank (16) forming the side walls (20) onto the pre-formed plastics film (12).

12. Production device (32) according to claim 11, characterized in that the film pre-forming unit (34) has at least one heating device (38) for heating the plastics film (12) before and / or during pre-forming of the plastics film (12).

13. Production device (32) according to claim 12, characterized in that the heating device (38) is formed at least partially in one piece with the stamping tool (36).