Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B50/00—Making rigid or semi-rigid containers, e.g. boxes or cartons
  • B31B50/74—Auxiliary operations
  • B31B50/742—Coating; Impregnating; Waterproofing; Decoating
  • B31B50/745—Coating or impregnating formed boxes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B2110/00—Shape of rigid or semi-rigid containers
  • B31B2110/10—Shape of rigid or semi-rigid containers having a cross section of varying size or shape, e.g. conical or pyramidal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B2110/00—Shape of rigid or semi-rigid containers
  • B31B2110/30—Shape of rigid or semi-rigid containers having a polygonal cross section
  • B31B2110/35—Shape of rigid or semi-rigid containers having a polygonal cross section rectangular, e.g. square
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B2120/00—Construction of rigid or semi-rigid containers
  • B31B2120/002—Construction of rigid or semi-rigid containers having contracted or rolled necks, having shoulders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
  • B31B2120/00—Construction of rigid or semi-rigid containers
  • B31B2120/40—Construction of rigid or semi-rigid containers lined or internally reinforced
  • B31B2120/402—Construction of rigid or semi-rigid containers lined or internally reinforced by applying a liner to already made boxes, e.g. opening or distending of the liner or the box
  • B31B2120/404—Construction of rigid or semi-rigid containers lined or internally reinforced by applying a liner to already made boxes, e.g. opening or distending of the liner or the box using vacuum or pressure means to force the liner against the wall

Definitions

• the present invention relates to a method for coating a packaging tray with a coating film using a tray coating station, a tray coating station or a packaging machine comprising a tray coating station.
• the technical problem to be solved is to specify a method and/or a device that enables the simple and reliable coating of a packaging tray with a film.
• the film should be easily removable from the packaging tray after coating, in order to recycle at least the packaging tray.
• the packaging tray can be flat and have a circumferential rim.
• the packaging tray can have a contour, in particular a recess, with the circumferential rim, at least in sections.
• the rim can have a first side and a second side, in particular wherein the second side is opposite the first side.
• the second side can have an inner and an outer section, in particular wherein the inner section is located between the outer section.
• the packaging tray receptacle can contact the inner section of the rim of the packaging tray and optionally an intermediate section of the packaging tray to receive the packaging tray.
• the packaging tray receptacle can be configured to not contact the outer section of the rim of the packaging tray.
• the outer clamping area and/or the inner clamping area can be completely enclosed.
• multiple clamping areas, in particular opposing clamping areas, can be provided.
• the clamping of the coating film between the upper and lower tool parts can be understood spatially, thus representing both direct and indirect clamping.
• the outer clamping area can be clamped directly via the upper tool part, in particular a clamping surface of the upper tool part, and the lower tool part, in particular a clamping surface of the lower tool part.
• the outer clamping area can be clamped indirectly to the upper tool part via a clamping frame, in particular a clamping frame surface.
• the clamping frame can be movably mounted on the upper tool part.
• the clamping frame can have at least one drive, in particular a pneumatic one. The drive can be mounted between the upper tool part and the clamping frame, in particular outside the area in which the coating film is arranged.
• the clamping frame can be moved towards the upper tool part so that the outer clamping area of the coating film is clamped between them.
• the clamping frame can be moved to varying distances towards the upper tool part.
• the clamping force can be generated between the upper tool part and the clamping frame.
• a gap can exist between the clamping frame and the upper tool part, while the outer clamping area of the coating film is clamped between the upper tool part and the clamping frame.
• the clamping frame can, for example, be plate-shaped.
• the clamping frame can be spatially arranged between the upper tool part and the lower tool part.
• the upper tool part and the clamping frame can be moved together towards the lower tool part, in particular pressed against it.
• the lower tool part can be moved towards the upper tool part, in particular the clamping frame, in particular pressed against it. This closes the gap between the clamping frame and the upper tool part.
• the clamping of the coating film arranged between the upper tool part and the clamping frame, in particular the clamping force acting on the coating film can be increased.
• the clamping force can be generated between the upper tool part and the lower tool part.
• the upper tool part can therefore be moved towards the lower tool part, in particular pressed against it, or vice versa.
• the lower tool part can be moved towards the clamping frame, in particular pressed against it.
• the upper tool part, together with the clamping frame and the clamped outer clamping area can be moved relative to the lower tool part, in particular towards the lower tool part, in particular pressed against it.
• the dome can be moved towards the lower part of the tool or the packaging tray holder to clamp the inner clamping area.
• a drive device in particular an electric, pneumatic, or hydraulic one.
• the dome in particular a dome clamping surface, can be pressed against the packaging tray, in particular the first side of the edge of the packaging tray, at the packaging tray receptacle, in order to clamp the inner clamping area.
• the protruding area can be located between the outer and inner clamping areas. To bulge the protruding area, it can be drawn under the edge of the packaging tray, particularly the second side of the edge, especially its outer section, using a suction and/or blowing device, or pressed with compressed air.
• the protruding area can be bent under the edge, particularly the outer section of the edge. Before the protruding area is bent, a first distance of the dome clamping surface with respect to the base of the lower tool part can be greater than a second distance of the upper tool clamping surface with respect to the base of the lower tool part, particularly in a side view. This allows the protruding area to be easily bent under the edge of the packaging tray.
• the upper tool part and/or the lower tool part can each have at least one opening for introducing air into and exhausting it from the closed tray coating station. Before arching, the overhanging area can be heated by the heated dome to such an extent that the overhanging area is stretchable.
• the double fold can be formed on the outer section of the rim.
• the curved overhang can be pressed against the packaging tray by means of the press insert, in particular a press insert surface.
• the press insert can be mounted, for example, on the lower part of the tool or the packaging tray holder and moved towards the rim of the packaging tray.
• the press insert surface can be as large as or smaller than the outer section, in particular its surface, of the second side of the rim.
• the press insert, in particular the press insert surface can be heated by means of a heating device, in particular an electric one.
• the temperature of the press insert can depend on the coating film, in particular its material and/or its thickness.
• the temperature of the press insert can be lower than the melting point of the coating film.
• the temperature of the press insert can be high enough that the coating film is stretchable.
• the temperature of the press insert can be greater than 80 °C, preferably greater than 100 °C, preferably greater than 120 °C.
• the temperature of the press insert can be less than 250 °C, in particular less than 200 °C, preferably less than 180 °C.
• air can be blown into the tray coating station through the opening in the upper part of the tool and/or through an opening in the dome.
• air can be drawn out of the tray coating station through the opening in the lower part of the tool. This presses the coating film against the packaging tray to prevent it from detaching.
• the double fold is positively connected to the packaging tray, and in particular, not materially bonded.
• This allows the packaging tray and the coating film to be completely separated. This can be particularly advantageous for recycling the packaging tray and/or the coating film.
• the process and/or the design of the tray coating station is ideally simplified. A heating device and the energy required to seal the coating film to the packaging tray can be eliminated.
• a unit for applying the adhesive can also be omitted. Ideally, the installation space can be reduced, maintenance requirements lowered, and/or operating and manufacturing costs reduced.
• the packaging tray comprises fibrous material, in particular paper or cardboard.
• fibrous material in particular paper or cardboard.
• the packaging tray and/or the coating film can comprise recyclable material.
• the coating film is a mono-film, in particular consisting of amorphous polyethylene terephthalate (APET).
• APET amorphous polyethylene terephthalate
• the coating film can comprise plastic.
• the thickness of the coating film can be less than 150 ⁇ m, preferably less than 100 ⁇ m, and particularly less than 90 ⁇ m, especially in its unformed state.
• the thickness of the coating film can be greater than 60 ⁇ m, preferably greater than 70 ⁇ m, and particularly greater than 80 ⁇ m, especially in its unformed state.
• the thickness of the coating film can be constant, especially in its unformed state.
• the coating film can comprise several film layers. The film layers can be the same or different.
• the inner clamping area is clamped to the first side of the rim, and the double fold is formed on the second side of the rim, which faces the first.
• the first side of the rim can face the upper part of the tool, in particular the dome, especially the dome clamping surface.
• the second side of the rim can face the lower part of the tool, in particular the packaging tray receptacle.
• the double fold comprises a first layer and a second layer, the first layer abutting the second side of the edge of the packaging tray and the second layer abutting the first layer.
• the first layer can be bonded to the second layer.
• This allows for a secure attachment of the coating film to the packaging tray, especially in contrast to a simple fold, thus enabling a reliable coating.
• a bond between the first and second layers of the double fold is not necessary.
• a bond between the first and second layers can make the double fold and the coating particularly stable and secure.
• the second layer can be heated, particularly by the heat from the heated dome and/or upon contact with the heated press insert, to such an extent that it melts, at least partially.
• the molten second layer can then be bonded to the first layer by pressing it against the first layer.
• the heated press insert can be heated to a temperature above the melting point of the coating film.
• the temperature of the press insert can be at least as high as the melting point.
• the size of the first layer and/or the second layer can depend on the edge of the packaging tray, in particular the outer section of the second side of the edge, and/or the press insert, in particular the press insert surface, and/or the method of separating the coating film.
• the first layer and the second layer in particular their areas, can be substantially the same size.
• the second layer especially after separation, can be smaller than the first layer.
• the second layer can, especially when separated with a knife, completely cover the first layer. Especially when separated without a knife, the second layer can partially cover the first layer.
• the coating film is separated while the inner clamping area and the packaging tray are clamped, and while the double fold and the packaging tray are clamped.
• This allows for safe and precise separation. It prevents the double fold from being damaged by forces acting during separation or even the coating film from being detached from the packaging tray.
• the coating film is cut, particularly with a knife, or torn, particularly by means of compressed air and/or tensile force.
• the coating film can be cut, particularly in the separation zone, upon contact with the knife.
• the coating film, particularly the separation zone can be moved relative to the knife, or vice versa.
• the knife can be fixed to the lower part of the tool.
• the packaging tray holder can be connected to the lower part of the tool, particularly via at least one The (compression) spring connected to the packaging tray holder can be movably mounted on the lower tool part. The packaging tray holder, together with the clamped coating film, can be moved towards the lower tool part and the blade.
• the blade can be movably mounted on the lower tool part, in particular the packaging tray holder.
• a drive unit in particular an electric, pneumatic, or hydraulic one.
• the blade can be moved towards the upper tool part to cut the coating film.
• the blade can be arranged spatially outside the packaging tray holder, in particular the press insert, in particular such that the blade can move outside the packaging tray holder, in particular the press insert.
• the blade when the blade is moved towards the upper tool part, it can move past the edge of the packaging tray. This ensures that the coating film is cut in the separation area.
• the tensile stress in the separation zone is increased to at least the tensile strength of the coating film in order to separate the coating film in the separation zone.
• the tensile stress can be generated by means of the suction and/or blowing device, in particular by drawing air from or blowing it into the closed tray coating station.
• the tensile stress of the coating film is at least equal to its tensile strength, it can tear.
• the tensile strength of the coating film can be its tear strength. It can indicate the maximum mechanical tensile stress with which the coating film can be subjected before it tears.
• the tensile stress required to separate the coating film can depend on the temperature of the press insert and/or the heated dome described below.
• its tear strength can be locally reduced.
• the heating can be carried out by means of the heated press insert and/or by means of a heated dome and/or outer dome such that the separation area of the coating film has a temperature gradient that increases towards the inner clamping area and/or curved overhang area and/or double fold.
• the temperature gradient can reduce the tensile strength of the heated separation area, particularly compared to a cold state, i.e., at room temperature, at least section by section, especially in the warmest section, by 4–15 N/ mm2 .
• the tensile strength of the coating film in a cold state can be approximately 20 N/ mm2 .
• the warmest section of the coating film can be heated to a temperature at which the tensile strength is only approximately 10 to 16 N/ mm2 .
• the temperature at the warmest section of the separation zone can be equal to or less than the temperature of the press insert, the dome, and/or the outer dome.
• the temperature gradient at the separation zone can be less than 90 °C, particularly less than 70 °C.
• the temperature gradient at the separation zone can be greater than 40 °C, particularly greater than 50 °C.
• the coating film can be separated at the warmest section.
• the warmest section can be adjacent, particularly directly, to the double fold, particularly its second layer.
• the dome, the packaging tray holder, and the press insert are moved relative to the lower tool section, or vice versa, to increase the tensile stress in the separation area.
• This has the advantage that no additional component is required to tension the coating film.
• the dome, the packaging tray holder, and the press insert can therefore each perform a dual function: on the one hand, clamping the inner clamping area of the coating film to the packaging tray, holding the packaging tray, or pressing the double fold; and on the other hand, generating or increasing the tensile stress in the separation area of the coating film.
• the dome's drive device can be designed to actively move the dome and passively move the packaging tray holder and the press insert.
• the packaging tray holder and the press insert can move along with it without an additional drive. This reduces the required installation space, maintenance requirements, and costs for the tray coating station and the process.
• the packaging tray holder can be movable relative to the lower tool part via a drive, particularly an electric, pneumatic, or hydraulic one. Relative movement is particularly possible when the inner clamping area and the packaging tray are clamped, and when the double fold and the packaging tray are clamped. If the coating film is to be tensioned but not torn, the relative movement must be limited to the extent that the tensile stress of the coating film does not increase to its tensile strength.
• the relative movement must be limited to the extent that the tensile stress of the coating film increases at least to its tensile strength.
• the degree of relative movement for tensioning and/or tearing can depend on the deformability and/or tear resistance of the coating film.
• the relative movement can be limited by a stop. In the simplest case, the lower or upper part of the tool can limit the movement.
• a section of the coating film between the outer clamping area is drawn against an inner surface of the dome, which is preferably heated, or pressed with compressed air to stretch the coating film.
• the coating film can be drawn against the inner surface by means of the suction and/or blowing device.
• the dome can have an opening for introducing or expelling air.
• the section of the coating film between the outer clamping area can comprise the overhang, the inner clamping area, an inner area between the inner clamping area, and optionally the separation area.
• the dome can have the dome clamping surface and an inner surface arranged between them.
• the dome clamping surface can be completely closed or have recesses.
• the dome can be flat.
• the dome can have a flat dome clamping surface and a flat inner surface.
• the dome can have at least one concavity.
• the dome can have a flat clamping surface and a concave inner surface.
• the dome, in particular the clamping surface and the inner surface can be heated by means of a heating device, especially an electric one. This warms the coating film, which can improve, and in particular increase, the stretchability of the coating film.
• the temperature of the dome can depend on the coating film, in particular its material and/or thickness.
• the temperature of the dome can be lower than the melting point of the coating film.
• the temperature of the dome can be high enough to allow the coating film to stretch.
• the temperature of the dome can be greater than 50 °C, preferably greater than 70 °C, and preferably greater than 100 °C.
• the temperature of the dome can be less than 160 °C, preferably less than 140 °C, and preferably less than 120 °C.
• the tray coating station can be evacuated during the stretching of the coating film.
• the tray coating station comprises an outer dome, which is particularly heatable. Specifically, after the outer clamping area is clamped, the area of the coating film between the outer clamping area and the outer dome is drawn against it or pressed against it using compressed air to stretch the coating film. The coating film can thus be drawn/pressed against a larger contact area formed by the dome and the outer dome.
• the dome can be located between the outer dome and the outer dome.
• the dome clamping surface and an outer dome surface that can contact the coating film can, preferably almost, lie on the same plane. This allows the coating film to be stretched easily and evenly, particularly without damaging it.
• the outer dome, and in particular the outer dome surface can be heated by means of the heating device.
• the dome can be heated.
• the dome and the outer dome can be heated via separate heating devices.
• the outer dome can be heated to essentially the same temperature as the dome.
• the inner area of the coating film is formed against the packaging tray, particularly the first side of the packaging tray.
• This allows the heated, stretched coating film to be easily shaped to the form of the packaging tray.
• the inner area can be drawn against the packaging tray, particularly by means of a suction and/or blowing device, or pressed against it using compressed air.
• the inner area of the coating film can cool and harden according to the contour of the packaging tray.
• the packaging tray holder can be cooled, particularly to less than 25 °C, preferably to less than 20 °C, and preferably to less than 10 °C.
• a further aspect of the invention relates to a tray coating station for coating a packaging tray with a coating film
• the tray coating station comprises: a tool upper part and a tool lower part for clamping an outer clamping area of the coating film, a packaging tray holder for receiving the packaging tray, a dome for clamping an inner clamping area of the coating film to the packaging tray, wherein the dome is movably arranged on the tool upper part, the inner clamping area being located within the outer clamping area, a suction and/or blowing device for forming an overhang of the coating film onto the packaging tray such that the overhang curves under an edge of the packaging tray, the overhang being located between the outer clamping area and the inner clamping area, and a heated press insert for pressing the curved overhang against the edge of the packaging tray such that a double fold is formed, the press insert being movable relative to the packaging tray holder, and a release agent for separating the coating film in a Separation area, wherein the separation area is located between the double fold and the outer clamp
• the release agent is a knife, and/or the release agent is formed by the suction and/or blowing device, wherein the suction and/or blowing device is designed to increase a tensile stress of the separation area, in particular to at least a tensile strength of the coating film, and/or the release agent is formed by the dome, the packaging tray holder and the press insert, wherein the dome, the packaging tray holder and the press insert are movable relative to the lower part of the tool. are to increase the tensile stress of the separation area, in particular to at least the tensile strength.
• the upper part of the tool comprises a clamping frame, which is movable relative to it, wherein the outer clamping area can be clamped indirectly between the upper part of the tool and the lower part of the tool via the clamping frame.
• the press insert is movably mounted on the lower part of the tool, in particular the packaging tray holder, and/or the packaging tray holder is movably mounted on the lower part of the tool.
• Another aspect of the invention relates to a packaging machine, preferably a tray sealing machine, comprising a tray coating station configured to carry out the method in at least one of the variants disclosed in this patent.
• the tray coating station can be in at least one of the variants disclosed in this patent.
• Figure 1 shows a schematic side view of a packaging machine 1 according to one embodiment. It may include a frame 2. The packaging machine 1 may also have a feed conveyor 3. It may also have a tray coating station 4, which will be described in more detail later. Empty packaging trays 5 can be conveyed to the tray coating station 4 via the feed conveyor 3. The packaging trays 5 can be transferred to the tray coating station 4 by a gripper 6 and reversibly coated there with a coating film 7. After coating, areas corresponding to the packages or packaging units can be cut out of the web of the coating film 7. A film remnant grid 8 of the coating film 7 remains, which is wound up by a device 9 for winding the film remnant grid 8. The packages coated in this way can be transferred from the tray coating station 4 to a discharge conveyor 10 via the gripper 6. From there, it can, for example, be forwarded to a filling station (not shown) to be filled with a product.
• a filling station not shown
• Figures 4 to 9 show the tray coating station 4 in a schematic sectional view at different phases of the coating process.
• the tray coating station 4 includes a packaging tray holder 13.
• a single packaging tray 5 is arranged on the packaging tray holder 13.
• Packaging tray 5 is described in detail in Figure 3
• the packaging tray 5, as shown in the present embodiment, comprises cardboard. This allows the packaging tray 5 to be manufactured in an environmentally friendly manner. Furthermore, the packaging tray 5 coated according to the described method can be easily separated from the coating film 7 and is therefore easily recyclable.
• Figure 3 shows only a section of the packaging tray 5 in which The state in which it is held by the packaging tray holder 13. The section shows the right side of the packaging tray 5; that is, the section can be mirrored on the left edge of the image to show the complete sectional view.
• the packaging tray 5 has a recess 14 with the surrounding rim 15.
• the rim 15 has a first side 16 and a second side 17 opposite the first side 16.
• the packaging tray 5 is arranged in the tray coating station 4 such that the first side 16 faces the upper tool part 11 and the second side 17 faces the lower tool part 12 (see Figure 1).
• Figure 2 The second side 17 has an inner section 18 and an outer section 19, with the inner section 18 located between the outer section 19.
• the packaging tray receptacle 13 contacts the inner section 18 of the packaging tray 5 as well as the side walls 20 of the packaging tray 5 located between the rim 15.
• the packaging tray receptacle 13 does not contact the outer section 19 of the rim 15 of the packaging tray 5. This is particularly necessary so that the coating process, as detailed below, can be carried out.
• the tray coating station 4 further comprises a tool upper part 11, a tool lower part 12 and a clamping frame 21. These serve to clamp a circumferentially closed outer clamping area 22 of the coating film 7 (see Figure 4
• the coating film 7 is placed between the clamping frame 21 and the tool upper part 11, and the clamping frame 21 is moved upwards to a tool upper clamping surface 23 of the tool upper part 11 and pressed against it (see Figure 4
• the coating film 7 is a monofilm consisting of amorphous polyethylene terephthalate (APET) with a constant thickness of approximately 80 ⁇ m (in its unformed state). This improves the durability of the coating film 7 and reduces its weight.
• APET amorphous polyethylene terephthalate
• the coating film 7, as in Figure 5 shown heated, and stretched.
• a dome 26 with a heated concave inner surface 27 is provided at the shell coating station 4.
• a section 25 of the coating film 7, located between the outer clamping area 22, is drawn onto the heated inner surface 27 by means of a suction device (not shown).
• an opening 24 for air extraction is provided in the dome 26.
• the stretched coating film 7 can then be used in a subsequent step (see Figure 7 ) simply adapted to the size of the packaging tray 5 and molded to it.
• the stretched area 25 of the coating film 7 includes a protruding area 28, described in more detail below, and a completely closed inner clamping area 29, an inner area 30 between the inner clamping area 29 and a separation area 31 (see Figure 6 , 7 , 9, 10 , 12
• the dome 26 comprises, in addition to the heated concave inner surface 27, a similarly heated flat dome clamping surface 32 that surrounds the inner surface 27.
• the dome 26 is heated by an electric heating device (not shown) to a temperature below the melting point of the coating film 7, in this case to approximately 60 °C.
• the coating film 7 is heated sufficiently to become more easily and widely stretched.
• contact with the heated dome 26 also heats the protruding area 28 of the coating film 7, located between the outer clamping area 22 and the inner clamping area 29, to the point where it becomes stretchable.
• the tray coating station 4 While the coating film 7 is suctioned onto the dome 26, as in Figure 6 As shown, the tray coating station 4 is closed. For this purpose, the lower tool part 12 is moved upwards towards the upper tool part 11 and the clamping frame 21 and pressed against it. In the present embodiment, the coating film 7 is thus indirectly clamped between the upper tool part 11 and the lower tool part 12 via the clamping frame 21. Closing the tray coating station 4 also further reinforces the clamping of the outer clamping area 22 of the coating film 7, so that the subsequent steps of the coating process can be carried out.
• the packaging tray holder 13 along with the packaging tray 5 mounted on it, moves along with it.
• the dome 26 moves towards the lower tool part 12.
• the dome 26, the lower tool part 12, and the packaging tray holder 13 are moved until the coating film 7 contacts a dome clamping surface 32 of the dome 26 at the inner clamping area 29, thus clamping the inner clamping area 29 to the first side 16 of the edge 15 of the packaging tray 5.
• the inner clamping area 29 is located within the outer clamping area 22.
• the tray coating station 4 was evacuated in the previous process step, it is possible to apply the coating film 7 to the packaging tray 5 particularly quickly and without wrinkling. Furthermore, the heating and stretching of the coating film 7 carried out in the previous step contributes to the fact that the coating film 7 can be easily shaped to the form of the packaging tray 5 without being damaged.
• the coating film 7 cools and hardens according to the contour of the packaging tray 5.
• the suction action shapes the heated overhang 28 against the packaging tray 5 in such a way that the overhang 28 curves under the edge 15 of the packaging tray 5.
• the overhang area 28 is curved so that it is curved into the area of the outer section 19 of the second side 17 of the edge 15.
• the curvature is favored by the fact that a first distance 34 of the dome clamping surface 32 with respect to a base 35 of the lower tool part 12 is greater than a second distance 36 of the upper tool clamping surface 23 with respect to the base 35.
• the curved overhang 28 is formed into a double fold 37.
• air is preferably blown through the openings 24 and 38 into the tray coating station 4 to press the coating film 7 against the packaging tray 5.
• a heated press insert 39 is movably mounted on the packaging tray holder 13 to form the double fold 37.
• a press insert surface 40 of the press insert 39 is heated by an electric heating device (not shown) to a temperature below the melting point of the coating film 7, in this embodiment to approximately 60 °C.
• the press insert 39 is moved upwards towards the packaging tray 5 and presses the curved overhang 28 against the outer section with its heated press insert surface 40.
• the resulting double fold 37 has two layers.
• a first layer 41 lies directly against the second side 17 of the rim 15 of the packaging tray 5.
• a second layer 42 lies directly against the first layer 41.
• the double fold 37 in contrast to a simple fold, enables a particularly secure attachment of the coating film 7 to the packaging tray 5 and thus a particularly secure coating.
• the inner clamping area 29 of the coating film 7 is clamped to the first side 16 of the rim 15, and the double fold 37 is formed on the second side 17 of the rim 15, which is opposite the first side 16.
• the coating film 7 and the packaging tray 5 There is no material bond between the coating film 7 and the packaging tray 5, but rather a purely form-fit connection.
• This makes it possible to attach the coating film 7 to the packaging tray 5 simply and reliably.
• the packaging tray 5 and the coating film 7 can be completely separated from each other. This is particularly advantageous for recycling the packaging tray 5 and/or the coating film 7.
• the coating process and the design of the tray coating station 4 are also simplified, for example, by eliminating the need for an adhesive and a device for applying it to the coating film 7 or the packaging tray 5. Ideally, the installation space of the shell coating station 4 will be reduced, maintenance effort reduced and/or operating and manufacturing costs lowered.
• the dome 26, the packaging tray holder 13, and the press insert 39, together with the clamped coating film 7, are lowered relative to the tool base 12 to increase the tensile stress of the separation area 31.
• the separation area 31 is located between the double fold 37 and the outer clamping area 22.
• the described relative movement has the advantage that no additional component is required to tension the coating film 7.
• the dome 26, the packaging tray holder 13, and the press insert 39 each perform a dual function: firstly, clamping the inner clamping area 29 of the coating film 7 to the packaging tray 5, holding the packaging tray 5, or pressing the double fold 37; and secondly, generating or increasing the tensile stress in the separation area 31 of the coating film 7.
• the dome 26 is actively driven by an electrical drive device (not shown).
• the packaging tray holder 13 and the press insert 39 are passively moved along with the dome 26. That is, there is only one drive device. This is necessary, which saves installation space and reduces the effort and costs for the operation and maintenance of the tray coating station 4.
• the described movement is carried out to such an extent that the coating film 7 is stretched but not torn.
• the tensile stress is increased to such an extent that the tensile strength of the coating film 7 is not reached.
• the tensile strength of the coating film indicates its tear resistance. It specifies the maximum mechanical tensile stress with which the coating film 7 can be subjected before it tears. Tensioning the separation area 31 is particularly advantageous for the separation of the coating film 7 described below.
• the coating film 7 is separated while the inner clamping area 29 and the packaging tray 5 are clamped, and the double fold 37 and the packaging tray 5 are clamped. This enables safe and controlled separation. Furthermore, it prevents the double fold 37 from being damaged by forces acting during separation or even the coating film 7 from being detached from the packaging tray 5.
• the tensile stress required to separate the coating film 7 is further reduced by the heat exerted on the separation area 31 by the press insert 39 and the heated dome 26, thereby lowering the tear strength of the coating film 7.
• the press insert 39 and the dome 26 heat the coating film 7 at the inner clamping area 29 and at the double fold 37 (see figure). Figures 5 to 8 ), so that the separation area 31 experiences a temperature gradient increasing towards the inner clamping area 29 and double fold 37.
• the temperature gradient reduces the tensile strength of the heated separation area 31, particularly compared to a cold state (i.e., at room temperature), at least sectionally, especially at a warmest section 43, by about 10 N/ mm2 .
• the temperature at the warmest section 43 of the separation area 31 is about 80% of the temperature of the press insert 39 or the dome 26. Due to the action of temperature, tensile stress, and atmospheric pressure, the coating film 7 tears at the warmest section 43 of the separation area 31, which is directly adjacent to the second layer 42 of the double fold 37 (see Figure 13 ).
• Figure 10 Figure 1 shows an alternative method of separating the coating film 7 using the previously described tray coating station 4.
• the [details of the process] Figures 2 and 4 to 8 The process steps shown are applied identically in this second embodiment.
• the dome 26, the packaging tray holder 13, and the press insert 39 form the separating agent 47.
• the dome 26, the packaging tray holder 13, and the press insert 39, together with the clamped coating film 7 are lowered further relative to the tool base 12 to increase the tensile stress of the separation area 31 to at least its tensile strength.
• the coating film 7 tears. This enables particularly easy and reliable separation of the coating film 7.
• the degree of relative movement required depends on the deformability and/or tear resistance of the coating film 7.
• the tool base 12 forms a stop for the packaging tray holder 13 and limits the relative movement.
• the Figures 11, 12 and 14 show a shell coating station 4 according to a further embodiment in a schematic sectional view in different phases of the coating process, in particular during the pressing of the double fold 37 ( Figure 11 ) and when separating the coating film 7 ( Figure 12 ).
• the shell coating station 4 comprises, in addition to the dome 26, an outer dome 44 enclosing the dome 26.
• the outer dome 44 in particular an outer dome surface 45, is heatable and movably mounted on the upper part of the tool 11. After the outer clamping area 22 of the coating film 7 is clamped, the coating film 7 is, as shown in Figure 15 As shown, the coating film 7 is stretched.
• the area 25 of the coating film 7, located between the outer clamping area 22, is drawn against both the heated dome 26 and the heated outer dome 44.
• This provides a larger contact area for stretching the coating film 7, and the coating film 7 can be adapted particularly well to the size of the packaging tray 7.
• the dome 26 and the outer dome 44 are heated to approximately the same temperature by means of the same heating device.
• the dome clamping surface 32 and the outer dome surface 45, which each contact the coating film 7, are located almost on the same plane, i.e., equidistant from the base 35 of the tool lower part 12. This allows the coating film 7 to be stretched easily and evenly, and in particular without being damaged.
• the packaging tray is cut by a knife 46 as a separating agent 47.
• the knife 46 is fixedly mounted on the lower part of the tool 12. Spatially, the knife 46 is arranged outside the packaging tray receptacle 13, in particular the press insert 39, such that the packaging tray receptacle 13 and the packaging tray 5 can move past the knife 46 within the tool 46 (see figure).
• Figure 12 When the cutting area 31 comes into contact with the blade 46, it is cut. For this to occur, the packaging tray holder 13, together with the clamped coating film 7, is moved towards the lower tool part 12 and the blade 46.
• the relative movement required for cutting is at most large enough to increase the tensile stress of the coating film 7 at least to its tensile strength.
• the degree of relative movement required depends on the deformability and/or tear resistance of the coating film 7.
• the lower tool part 12 forms a stop for the packaging tray holder 13 and limits the relative movement.
• the coating film 7 is cut with the knife 46, it is advantageous that the coating film 7 is prepared before and during cutting, as shown in Figure 8
• the described downward movement of the dome 26, the packaging tray holder 13 and the press insert 39 together with the clamped coating film 7 relative to the tool base 12) is tensioned. This enables a particularly precise cut.
• FIG. 13 The coating film 7 is illustrated after separation by tearing using air pressure or by the relative movement of the dome 26, the packaging tray holder 13, and the press insert 39.
• the double fold 37 varies in size, especially after separation, depending on the size of the outer section 19 of the second side 17 of the edge 15 of the packaging tray 5, the size of the press insert 39, and the release agent 47 used.
• the release agent 47 influences the surface area of the second layer 42 of the double fold 37 compared to the first layer 41.
• the second layer 42 is smaller than the first layer 41.
• the second layer 42 only partially overlaps the first layer 41.
• the press insert area 40 is smaller than the outer section 19 of the second side 17 of the edge 15.
• the coating film 7 is torn at the warmest section 43 of the separation area 31, which is directly adjacent to the second layer 42 of the double fold 37.
• the warmest section 43 is located spatially outside the press insert 39 and even below the outer section 19 of the second side 17 of the edge 15.
• the second side 42 of the double fold 37 is smaller than its first layer 41.
• the first layer 41 and the second layer 42 of the double fold 37 are essentially the same size, and the second layer 42 completely covers the first layer 41 (see Figure 14 ). This is the case because the knife 46 cuts the coating film 7 outside the edge 15.

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• 2024
  • 2024-05-31 DE DE102024115219.2A patent/DE102024115219A1/de active Pending
• 2025
  • 2025-05-09 EP EP25175238.2A patent/EP4667208A2/fr active Pending

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