Packaging container and method for producing such packaging container

Abstract

A cardboard packaging container for bulk solids and a method of forming a cardboard packaging container for bulk solids. The container has a container body closed at one end by a lid formed by sequential insertion and attachment of a first cardboard insert and a second cardboard insert.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Swedish patent application No. 2250951-7 filed on August 5, 2022.

[0003] References

[0004] The disclosures of Swedish patent application No. 2250951-7 filed on August 5, 2022 are incorporated herein by reference in their entirety for all purposes as if set forth in their entirety herein. Technical Field

[0005] The present disclosure relates to a method of producing a paperboard packaging container for bulk solids and a paperboard container for bulk solids. Background Art

[0006] In the disposable container field for products such as infant formula, tobacco, detergents, it is always necessary to reduce the carbon footprint of such products by minimizing the resource use of disposable containers and making containers recyclable. The disposable container mentioned herein is a composite material container with a tubular body, which is made of a laminated sheet comprising a cardstock layer (that is, a layer mainly made of cellulose fibers). The upper end edge and the lower end edge of the container can include the plastic edge of the edge connected to the packaging container. This provides a pleasant and neat outward appearance for the packaging container, and the container top or bottom can also be more wear-resistant. The bottom of the container can be made by the inwardly folded end portion of the tubular body alternatively, or can be a bottom insert / disc attached to the tubular body at the bottom end. However, for this type of packaging container, outward appearance may be less attractive and less wear-resistant at the bottom end of the packaging container.

[0007] It is therefore an object of the present disclosure to provide an improved packaging container which provides better stability and easier opening of the lid of the container. Another object is to provide a method of manufacturing such a container. Summary of the invention

[0008] In one aspect, the present disclosure generally relates to a method for forming a cardboard packaging container for bulk solids. The method includes obtaining a body blank having a first side edge and a second side edge, the body blank being made of a laminated sheet including a cardboard substrate layer. The method includes forming a container body with the body blank, the container body defining an internal compartment, the container body including a container body wall, the container body wall having an inner surface facing the internal compartment, an outer surface facing away from the internal compartment, and a weakened portion extending along at least a portion of the circumference of the container body, the container body including a first end having a first end opening and a second end having a second end opening opposite to the first end. The method includes closing the first end opening by pressing a first cardboard insert into the first end opening to a first predetermined position relative to the container body and forming an external recess at the first predetermined position of the first cardboard insert, the first cardboard insert including a first central portion covering the first end opening and a first peripheral flange portion. The method includes attaching the first peripheral flange portion of the first cardboard insert to the container body wall at a first attachment portion of the container body, the weakened portion in the container body wall being located between the first attachment portion and the second end of the container body. The method includes pressing a second cardboard insert into the exterior recess through the first end opening to a second predetermined position relative to the container body, the second cardboard insert including a second central portion covering the first end opening and a second peripheral flange portion. The method includes attaching the second peripheral flange portion of the second cardboard insert to the container body wall.

[0009] According to another aspect, the present disclosure relates to a cardboard packaging container for bulk solids. The container includes a container body defining an internal compartment. The container body includes a container body wall made of a laminated sheet material, the laminated sheet material including a cardboard substrate layer. The container body includes a first end having a first end opening and a second end having a second end opening opposite to the first end. The container body wall has an inner surface facing the internal compartment and an outer surface facing away from the internal compartment. A first cardboard insert closes the first end opening, the first cardboard insert including a first central portion covering the first end opening and a first peripheral flange portion. The first cardboard insert is located in the container body and forms an external recess. The first peripheral flange portion is attached to the inner surface of the container body wall at a first attachment portion of the container body. The container body has a weakened portion extending along at least a portion of the circumference of the container body. The weakened portion is located between the first attachment portion and the second end of the container body. The packaging container also includes a second cardboard insert, which is positioned in the external recess and covers the first end opening. The second cardboard insert includes a second central portion and a second peripheral flange portion attached to the container body wall.

[0010] According to one aspect, in the following description and in the accompanying drawings, the above object is achieved by a method of forming a cardboard packaging container according to the subject matter of the claims. In one embodiment, the method is a method of forming a cardboard packaging container from a body blank. The method comprises the step a) of obtaining a body blank having a first side edge and a second side edge, the body blank being made of a laminated sheet including a cardboard substrate layer.

[0011] Furthermore, the method comprises the step b) of forming a tubular container body from the body blank.

[0012] In addition, the method includes step c) of sealing the first side edge and the second side edge together, wherein the tubular container body defines an internal compartment, wherein the container body includes a container body wall having an inner surface facing the internal compartment and an outer surface facing away from the internal compartment, and wherein the container body includes a first end having a first end opening and an opposite second end having a second end opening.

[0013] In addition, the method includes a step d), closing the first end opening by pressing a first cardboard insert into the first end opening to a first predetermined position relative to the container body, the first cardboard insert including a first central portion covering the first end opening and including a first peripheral flange portion away from the first central portion toward the first end opening of the container, thereby forming an external recess of the packaging container.

[0014] Furthermore, the method comprises the step e) of attaching a first peripheral flange portion of the first paperboard insert to the container body wall.

[0015] In addition, the method includes a step f), pressing a second cardboard insert into the external recess through the first end opening to a second predetermined position relative to the container body, the second cardboard insert including a second central portion covering the first end opening and including a second peripheral flange portion away from the second central portion toward the first end opening of the container body.

[0016] Furthermore, the method comprises the step g) of attaching a second peripheral flange portion of a second paperboard insert to the container body wall.

[0017] By attaching the first cardboard insert and the second cardboard insert to the container body wall, a double-walled lid structure is formed by the first cardboard insert and the second cardboard insert. The lid structure is stronger than the single-walled lid structure formed when only one cardboard insert is used, and therefore also stabilizes the lid for packaging containers with larger cross-sectional areas and produced with weaker materials. The increased stability of the lid also makes it easier to handle the lid when it is separated from the rest of the packaging container, while reducing the risk of cracking / deformation of the lid.

[0018] The method may also include step h), deforming the second central portion of the second cardboard insert before attaching the second peripheral flange portion to the container body wall, so that a recessed portion of the second cardboard insert is formed adjacent to the second peripheral flange, and the recessed portion is formed so that the distance between the second central portion of the second cardboard insert and the first central portion of the first cardboard insert is reduced at the recessed portion.

[0019] By deforming the second central portion before attaching the second peripheral flange portion to the container body wall, the material of the cardboard insert is free to move during deformation, allowing material of the cardboard blank used to form the cardboard insert to move from the peripheral portion of the second cardboard blank used to form the second cardboard insert, thereby reducing the stretching of the cardboard material during deformation of the second central portion of the second cardboard insert.

[0020] Step f) may be performed by forcing the second cardboard insert into the outer recess using a footprint surface of a pressing tool having a shape and size adapted to the shape and size of the first end opening of the container body and having protrusions for forming a recessed portion of the second cardboard insert.

[0021] Step f) may include positioning a guide plate adjacent to the first end opening of the container body so that a through cavity of the guide plate is aligned with the first end opening, the through cavity having a shape and size corresponding to the shape and size of the first end opening of the container body, wherein when the second cardboard insert is pressed into the external recess, the second cardboard insert is guided into the external recess through the through cavity of the guide plate, wherein the second peripheral flange portion is bent between the guide plate and the pressing tool.

[0022] The use of such a guide plate protects the first end of the container body so that deformation of the cardboard blank occurs primarily due to the forces of the guide plate and the pressing tool acting on the cardboard blank, rather than between the container body wall and the pressing tool.

[0023] The through cavity of the guide plate may have a recessed portion extending the through cavity transversely relative to an insertion direction along which the second cardboard insert is inserted into the outer recess, the recessed portion of the through cavity being positioned adjacent to where the protrusion of the cover surface passes through the through cavity.

[0024] The recessed portion reduces the area / edge length of the through cavity of the guide plate, on which the blank slides when deformed between the pressing tool and the guide plate, thereby increasing the local stress on part of the cardboard blank so that when the second peripheral flange portion is folded to point away from the second central portion of the second cardboard insert, the cardboard blank folds in the intended position.

[0025] According to a second aspect, the above-mentioned object is also achieved by a cardboard packaging container according to the claims, the following description and the accompanying drawings. The packaging container is suitable for bulk solids, and the container includes a tubular container body defining an internal compartment. The container body includes a container body wall made of a laminated sheet, the laminated sheet includes a cardboard substrate layer, and the container body includes a first end with a first end opening and an opposite second end with a second end opening. The container body wall has an inner surface facing the internal compartment in the packaging container and an outer surface facing away from the internal compartment. The first end opening is closed by a first cardboard insert, which includes a first central portion covering the first end opening. The first cardboard insert also includes a first peripheral flange portion, which is away from the first central portion toward the first end opening of the packaging container, so as to form an external recess of the packaging container. The first peripheral flange portion is attached to the inner surface of the container body wall at a first attachment portion of the container body. In addition, the container body has a weakened portion extending along at least a portion of the circumference of the container body, and the weakened portion is located between the first attachment portion and the second end of the container body. The packaging container also includes a second cardboard insert positioned in the exterior recess and covering the first end opening. The second cardboard insert includes a second central portion and a second peripheral flange portion away from the second central portion toward the first end opening of the packaging container. The second peripheral flange portion is attached to the inner surface of the container body wall, or alternatively attached to the first peripheral flange of the first cardboard insert.

[0026] Both the first cardboard insert and the second cardboard insert are attached to the container body wall. When opening the packaging container, the user grasps the first end of the container body, typically by grasping the second peripheral flange portion of the second cardboard insert, and pulls to separate the container body wall at the weakened portion. Since the weakened portion is located between the first attachment portion and the second end of the container body, the first cardboard insert and the second cardboard insert together form a lid including a tear-off portion or upper portion of the container body wall. The combination of the two cardboard inserts improves the rigidity of the lid and makes it easier to hold the lid during and after separation of the lid from the rest of the container body.

[0027] The second central portion of the second paperboard insert may include a recessed portion adjacent to the container body wall.

[0028] The recess adjacent the container body wall makes it easier for the user to grip the lid when tearing it off the rest of the container body by increasing the surface area available for the user to grip. The recess also provides the user with a visual indication of where to grip, thereby making it easier to remove the lid, because if the lid is pulled at any random location, it will be more difficult to pull the lid off the rest of the container.

[0029] The second paperboard insert may be formed from a paperboard blank including a central portion having a shape and size corresponding to the shape and size of the first end opening of the container body, and a peripheral portion surrounding the central portion.

[0030] like Figure 3 As shown in , the peripheral portion of the paperboard blank may be enlarged adjacent to the portion of the paperboard blank where the concave portion is formed.

[0031] By expanding the paperboard blank adjacent to where the recessed portion is to be formed, additional material can be used to form the recessed portion without reducing the amount of material available to form the second peripheral flange portion. This enables the second peripheral flange portion to be attached to the container using a weld or adhesive bond extending in a planar manner around the circumference of the first end opening of the packaging container.

[0032] The second central portion of the second paperboard insert may include a grip opening that may be covered by a removable cover.

[0033] The grip opening provides an alternative to the recess discussed above. The grip opening enables a user to grasp the lid through the grip opening, thereby reaching a larger surface area of ​​the lid for gripping. The grip opening may be covered by a separate lid member or membrane, or may be covered by a portion made of the same cardboard blank as the second cardboard insert by providing a score, perforation or the like extending at least partially around the circumference of the grip opening, so that the user accesses the opening by forcing the cover into the space between the first cardboard insert and the second cardboard insert, or by lifting or tearing off the cover.

[0034] like Figure 5 As shown in , the removable cover can be part of the second central portion that is integrally formed with the second paperboard insert and is at least partially surrounded by the perforations of the second central portion.

[0035] The cover may be hingedly connected to the second cardboard insert by a hinge. By connecting the cover with the hinge, the cover can be easily lifted and lowered to open and close the grip opening of the second cardboard insert, respectively. This allows the intermediate space between the first cardboard insert and the second cardboard insert to be used for storage purposes and allows easy and repeated access to objects stored in the intermediate space. For example, a spoon can be stored in the intermediate space and put back after using the spoon. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The invention will now be further explained by way of non-limiting examples and with reference to the accompanying drawings, in which:

[0037] Figure 1 A paperboard blank is shown for forming a container body.

[0038] Figure 2 A perspective view of a first embodiment of a packaging container of the present disclosure is shown, with a portion cut away to show a cross section of a lid of the packaging container.

[0039] Figure 3 shows the method for forming a Figure 2 A top view of a cardboard blank for a second cardboard insert for a lid of a packaging container is shown in FIG.

[0040] Figure 4 A perspective view of a second embodiment of a packaging container of the present disclosure is shown, with a portion cut away to show a cross-section of a lid of the packaging container.

[0041] Figure 5 shows the method for forming a Figure 4 A top view of a cardboard blank for a second cardboard insert for a lid of a packaging container is shown in FIG.

[0042] Figure 6 A schematic cross-sectional view of a prior art packaging container is shown.

[0043] Figure 7 A schematic cross-sectional view of a first embodiment of a packaging container of the present disclosure is shown.

[0044] Figure 8 A schematic cross-sectional view of a second embodiment of a packaging container of the present disclosure is shown.

[0045] Fig. 9 A schematic cross-sectional view of a first paperboard insert pressed into a packaging container of the present disclosure is shown.

[0046] Fig.10 A method for guiding the first cardboard insert into Fig. 9 A schematic top view of a guide plate in a packaging container is shown.

[0047] Fig.11 A schematic cross-sectional view of a second paperboard insert pressed into a packaging container of the present disclosure is shown.

[0048] Fig.12 A method for guiding the second cardboard insert into Fig.11 Schematic top view of a guide plate in a packaging container shown in .

[0049] Fig.13 Shows the corresponding Fig.12 Schematic diagram of a view of, but at a later stage of insertion of the second cardboard insert into the packaging container. The plunger is depressed to apply pressure along the circumference of the second peripheral flange portion of the second cardboard disc to allow the second cardboard disc to be attached to the container body wall by welding.

[0050] Fig.14 Shows Fig.13 , indicating the location of the attachment portion around which the first peripheral flange is attached to the container body wall. Also shown is a weakened portion of the container body positioned between the attachment portion and the bottom end (second end) of the packaging container. This positioning of the weakened portion allows the double-walled lid to be separated from the rest of the container body by tearing the lid off from the rest of the container body at the weakened portion.

[0051] In all the drawings, the same reference numerals denote similar features. For better visibility, reference numerals may be omitted in some of the drawings, in which case reference is made to other drawings. DETAILED DESCRIPTION

[0052] It should be understood that the drawings are schematic and that various components, such as material layers, are not necessarily drawn to scale. The steps in the method of forming a packaging container and the packaging container shown in the drawings are provided by way of example only and should not be considered to limit the present disclosure.

[0053] First, an exemplary embodiment of the packaging container 1 will be described with reference to the drawings. Then, a method of manufacturing the packaging container 1 will be described.

[0054] like Figure 2 and Figure 8 As shown in , the packaging container 1 includes a tubular container body 2, which defines an internal compartment 28. The container body 2 includes a container body wall 7, which is made of a laminated sheet including a cardboard substrate layer, and the container body 2 includes a first end 3 having a first end opening 4 and an opposite second end 5 having a second end opening 6. The container body wall 7 has an inner surface 8 facing the internal compartment 28 in the packaging container 1 and an outer surface 9 facing away from the internal compartment 28. The first end opening 4 is closed by a first cardboard insert 12a, and the first cardboard insert 12a includes a first central portion 121a covering the first end opening 4. The first cardboard insert 12a also includes a first peripheral flange portion 13a, which is away from the first central portion 121a toward the first end opening 4 of the packaging container 1, so that an external recess 122 of the packaging container 1 is formed. The first peripheral flange portion 13a is attached to the inner surface 8 of the container body wall 7 at a first attachment portion 129 of the container body 2.

[0055] In addition, for example Fig.14As shown in the enlarged portion C of the container body 2, the container body 2 has a weakened portion 130 extending along at least a portion of the circumference of the container body 2, between the first attachment portion 129 and the second end 5 of the container body 2. In this embodiment, the weakened portion 130 includes a perforation extending around the entire circumference of the packaging container 1, but in other embodiments, any other suitable type of weakening, such as a fold line or a tear-off tape, may be used instead. In this embodiment, the perforation only partially extends through the container body wall 7, so that the sealing layer on the inner side of the paperboard is not perforated.

[0056] like Fig.14 As shown in the figure, the first peripheral flange portion 13a preferably extends through the weakened portion 130 so that (once the packaging container 1 is opened by tearing off the lid at the weakened portion 130 of the container body 2) the lid including the first cardboard insert 12a can be guided by the peripheral flange portion into the container body 2 when the lid of the packaging container 1 is closed.

[0057] The above-described structure of the container body 2 is common to all embodiments of the packaging container 1 of the present disclosure, and corresponds to Figure 6 The container body 2 shown in FIG.

[0058] like Figure 2 and Figure 8 , the packaging container 1 further comprises a second cardboard insert 12b positioned in the outer recess 122 and covering the first end opening 4. The second cardboard insert 12b comprises a second central portion 121b and a second peripheral flange portion 13b away from the second central portion 121b towards the first end opening 4 of the packaging container 1. The second peripheral flange portion 13b is attached to the inner surface 8 of the container body wall 7. Alternatively, without departing from the scope of the present disclosure, the second peripheral flange 13b may be attached to the first peripheral flange 13a of the first cardboard insert 12a.

[0059] In the illustrated embodiment, both the first cardboard insert 12a and the second cardboard insert 12b are attached to the container body wall 7. When opening the packaging container 1, the user grasps the first end 3 of the container body 2, typically by grasping the second peripheral flange portion 13b of the second cardboard insert 12b and pulling to separate the container body wall 7 at the weakened portion 130. Since the weakened portion 130 is between the first attachment portion 129 and the second end 5 of the container body 2, the first cardboard insert 12a and the second cardboard insert 12b together form a lid, which includes a tear-off portion (e.g., an upper portion) of the container body wall 7 separated at the weakened portion. The combination of the two cardboard inserts 12a, 12b improves the rigidity of the lid and makes it easier to hold the lid during and after the lid is separated from the rest of the container body 2.

[0060] like Figure 2 and Figure 8 As shown in FIG. 1 , the second central portion 121b of the second paperboard insert 12b includes a recessed portion 123 adjacent to the container body wall 7. In other embodiments, more than one such recessed portion 123 may be provided.

[0061] The recessed portion 123 adjacent to the container body wall 7 makes it easier for the user to grip the lid when tearing it off the rest of the container body 2 by increasing the surface area available for the user to grip. The recessed portion also provides the user with a visual indication of where to grip, thereby making it easier to remove the lid, since if the lid is pulled at any random location, it will be more difficult to pull the lid off the rest of the container.

[0062] The second cardboard insert 12b is formed from a cardboard blank 131a. Figure 3 The paperboard blank 131a includes a central portion 132a having a shape and size corresponding to the shape and size of the first end opening 4 of the container body 2. Figure 3 The second paperboard insert 12b also includes a peripheral portion 133a surrounding the central portion 132a. The peripheral portion 133a of the paperboard blank 131a is enlarged adjacent to the location of the paperboard blank where the recessed portion 123 is formed.

[0063] By expanding the paperboard blank 131a adjacent to the location where the recessed portion is to be formed, additional material can be used to form the recessed portion without reducing the amount of material available to form the second peripheral flange portion. This also allows the second peripheral flange portion to be attached to the container using a weld or adhesive bond extending around the circumference of the first end opening 4 of the packaging container 1 in a planar manner.

[0064] As indicated above, in other embodiments, the second central portion 121b of the second paperboard insert 12b may alternatively include a grip opening 136 instead of a recessed portion 123. Figure 4 and Figure 5 As shown in , the grip opening 136 may be covered by a removable cover 137 .

[0065] The grip opening 136 provides an alternative to the recessed portion 123 discussed above. The grip opening 136 enables a user to grasp the lid of the packaging container 1 through the grip opening 136, thereby reaching a larger surface area of ​​the lid for gripping. The grip opening 136 can be covered by a separate lid member or film, or can be covered by a portion of the same cardboard blank material as the second cardboard insert 12b by providing a score, perforation or the like extending at least partially around the circumference of the opening, so that the user can pass through the opening by forcing the cover 137 into the space between the first cardboard insert 12a and the second cardboard insert 12b, or by lifting or tearing off the cover 137.

[0066] The movable / removable cover 137 may be a portion of the second central portion 121b that is integrally formed with the second paperboard insert 12b and is at least partially surrounded by the perforations of the second central portion 121b.

[0067] The cover 137 can be hingedly connected to the second cardboard insert 12b by a hinge 139. By connecting the cover 137 with the hinge 139, the cover can be easily lifted and lowered to open and close the grip opening 136 of the second cardboard insert 12b, respectively. This allows the intermediate space between the first cardboard insert 12a and the second cardboard insert 12b to be used for storage purposes and allows easy repeated access to objects stored in the intermediate space. For example, a spoon can be stored in the intermediate space for easy access and replacement after use. The hinge 139 is typically a non-perforated part of the second cardboard insert 12b, but in other embodiments can be a piece of resilient material, such as a sheet, attached to the cover 137 and the second cardboard insert 12b by an adhesive or by welding.

[0068] Although any suitable method may be used to produce the packaging container 1 , an exemplary method of producing the packaging container 1 will be described below with reference to the accompanying drawings.

[0069] The method comprises step a), obtaining a main body blank 134, the main body blank having a first side edge 135a and a second side edge 135b, the main body blank 134 being made of a laminated sheet including a card paper substrate layer. Figure 1 Schematically shown in . The method also includes step b) of forming a tubular container body 2 from a body blank 134; and step c) of sealing the first side edge 135a and the second side edge 135b together. The tubular container body 2 defines an internal compartment 28. In addition, the container body 2 includes a container body wall 7, which has an inner surface 8 facing the internal compartment 28 and an outer surface 9 facing away from the internal compartment 28. The container body 2 includes a first end 3 with a first end opening 4 and an opposite second end 5 with a second end opening 6.

[0070] like Fig. 9 As shown in , the method further comprises a step d), closing the first end opening 4 by pressing a first cardboard insert 12a into the first end opening 4 to a first predetermined position P1 relative to the container body 2, the first cardboard insert 12a comprising a first central portion 121a covering the first end opening 4, and comprising a first peripheral flange portion 13a away from the first central portion 121a toward the first end opening 4 of the container 1, so that an external recess 122 of the packaging container 1 is formed. Fig. 9 As shown in , the dots represent the contents of the interior compartment 28 of the packaging container 1. Alternatively, the contents may be filled into the container body 2 from the bottom / second end 5 of the container body after one or both of the paperboard inserts 12a, 12b have been inserted into the container body.

[0071] The method further comprises a step e) of attaching the first peripheral flange portion 13a of the first paperboard insert 12a to the container body wall 7. For example, a suitable type of welding may be used for said attachment.

[0072] Furthermore, the method comprises a step f) of pressing a second cardboard insert 12b through the first end opening 4 into the outer recess 122 to a second predetermined position P2 relative to the container body 2, the second cardboard insert 12b comprising a second central portion 121b covering the first end opening 4 and comprising a second peripheral flange portion 13b away from the second central portion 121b towards the first end opening 4 of the container body 2. The second predetermined position P2 is located above the first predetermined position P1 in the container body 2.

[0073] Furthermore, the method comprises a step g) of attaching the second peripheral flange portion 13b of the second paperboard insert 12b to the container body wall 7. For example, a suitable type of welding may be used for said attachment.

[0074] By additionally pressing the second cardboard insert into the outer recess and attaching it to the container body wall, a double wall lid structure is formed by the first cardboard insert 12a and the second cardboard insert 12b. The lid structure is stronger than the single wall prior art lid structure formed when only one cardboard insert 12a is used.

[0075] The method may also include step h), deforming the second central portion 121b of the second cardboard insert 12b before attaching the second peripheral flange portion 13b to the container body wall 7, so that a recessed portion 123 of the second cardboard insert 12b is formed adjacent to the second peripheral flange 13b, and the recessed portion 123 is formed so that the distance D between the second central portion 121b of the second cardboard insert 12b and the first central portion 121a of the first cardboard insert 12a is reduced at the recessed portion 123.

[0076] By deforming the second central portion before attaching the second peripheral flange portion to the container body wall, the material of the cardboard insert is free to move during deformation, so that the material of the cardboard blank used to form the second cardboard insert 12b can move from the peripheral portion of the second cardboard blank used to form the second cardboard insert 12b, thereby reducing the stretching of the cardboard material during deformation of the second central portion of the second cardboard insert 12b.

[0077] like Fig.11 and Fig.13 As shown in , step f) can be performed by forcing the second paperboard insert 12b into the outer recess 122 using the footprint surface 53 of the pressing tool 27. The footprint surface 53 has a shape and size that matches the shape and size of the first end opening 4 of the container body 2, and has a protrusion 128 for forming the recessed portion 123 of the second paperboard insert 12b. Without departing from the present disclosure, the protrusion 128 of the pressing tool 27 can be formed integrally with the footprint surface 53 of the pressing tool, or provided as a separate member attached to the pressing tool to modify the footprint surface.

[0078] like Fig.11 , Fig.12 and Fig.13 As shown in , step f) may include positioning the guide plate 125 adjacent to the first end opening 4 of the container body 2 so that the through cavity 126 of the guide plate 125 is aligned with the first end opening 4, and the through cavity 126 has a shape and size corresponding to the shape and size of the first end opening 4 of the container body 2. When the second cardboard insert 12b is pressed into the outer recess 122, the second cardboard insert 12b is guided into the outer recess 122 through the through cavity 126 of the guide plate 125, wherein the second peripheral flange portion 13b is bent between the guide plate 125 and the pressing tool 27.

[0079] The guide plate 125 typically also includes an alignment recess 138 shaped to align the paperboard blanks 131 a , 131 b with the through cavity 126 of the guide plate 125 .

[0080] The use of such a guide plate 125 protects the first end 3 of the container body 2 so that deformation of the cardboard blank occurs mainly due to the force of the guide plate and the pressing tool acting on the cardboard blank, rather than between the container body wall 7 and the pressing tool 27.

[0081] It should be understood that two different pressing tools 27 may be needed: one for the first cardboard insert 12a and another for the second cardboard insert 12b. It can be seen that the pressing tool 27 for the first cardboard insert 12a does not have a protrusion 128 for forming a recess, while the pressing tool 27 for the second cardboard insert 12b may have such a protrusion 128, such as Fig.11 If there is no recessed portion 123 in the second paperboard insert 12b, the same pressing tool 27 can be used for both the first paperboard insert 12a and the second paperboard insert 12b.

[0082] Similarly, if Fig.10 and Fig.12 As shown in FIG. 2 , two different guide plates 125 may be needed: one for the first paperboard insert 12a and another for the second paperboard insert 12b.

[0083] The through cavity 126 of the guide plate 125 for the second cardboard insert 12b has a recessed portion 127 that extends the through cavity 126 transversely with respect to the insertion direction ID along which the second cardboard insert 12b is inserted into the outer recess 122. The recessed portion 127 of the through cavity 126 is located adjacent to the position where the protrusion 128 of the footprint surface 53 passes through the through cavity 126.

[0084] The recessed portion 127 reduces the area / edge length of the through cavity of the guide plate 125, and the cardboard blank slides on the through cavity of the guide plate 125 when deformed between the pressing tool 27 and the guide plate 125, thereby increasing the local stress on part of the cardboard blank, so that when the second peripheral flange portion is folded to point away from the second central portion of the second cardboard insert 12b, the cardboard blank is folded at the expected position.

[0085] The concave portion 127 of the through cavity 126 has a dovetail shape.

[0086] The dovetail shape provides a relatively sharp corner at the opening of the recessed portion, thereby enabling better control over where the material of the blank folds as it is pressed through the guide plate 125 .

[0087] The protrusion 128 of the footprint surface 53 may include an outer surface portion 128a that faces the container body wall 7 when inserted into the outer recess 122. When inserted into the outer recess 122, the outer surface portion 128a has a shape corresponding to the shape of an adjacent portion of the container body wall 7, wherein the width W1 of the opening of the recessed portion 127 corresponds to the width W2 of the outer surface portion 128a of the protrusion 128 of the footprint surface 53. In one example, the shape of the outer surface portion 128a is curved to correspond to the curved shape of the adjacent portion of the container body wall 7. The outer surface portion 128a may have other shapes (e.g., straight) without departing from the present disclosure.

[0088] The correspondence between the width of the outer surface portion and the width of the opening of the recessed portion concentrates stress on the paperboard material of the blank, thereby improving control of the folding position of the blank material as it is pressed through the guide plate.

[0089] In other embodiments, for example if a cardboard quality is selected for the cardboard blank, the recessed portion 127 may not be needed. Therefore, the recessed portion 127 may also be omitted. In some embodiments, the recessed portion 127 may have some other suitable shape that promotes a predeterminable deformation of the peripheral portion of the cardboard blank 11a, 131b.

[0090] The pressing tool 27 can be Fig. 9 , Fig.11 , Fig.13 and Fig.14 The configuration shown in , and corresponds to the "positioning unit" explained in further detail in US Pat. No. 11,292,625, which is incorporated herein by reference for all purposes. However, any other suitable pressing tool, such as a suitably shaped piston, may be used instead.

[0091] Furthermore, the retaining device 23 is used to position and support the container body 2 during the insertion of the paperboard inserts 12a, 12b into the container body 2. The retaining device 23 may correspond to the retaining device explained in further detail in US Pat. No. 11,292,625, which is incorporated by reference.

[0092] Thus, the retaining means 23 comprise at least one through positioning cavity suitable for receiving a portion of the container body 2 .

[0093] In order to achieve the above-mentioned attachment of the peripheral flange portion 12a, 13b of the cardboard insert to the container body 2, the holding device 23 includes a welding unit, preferably arranged around the positioning cavity. The welding unit (not shown) is suitable for welding the cardboard insert 12a, 12b to the container body 2, for example, by a welding unit including a coil extending around the positioning cavity. As explained herein, since the pressing tool 27 can be expanded in the radial direction of the positioning cavity, the corresponding cardboard insert 12a, 12b can be pressed against the welding unit. Any suitable welding technology can be used, such as ultrasonic welding or high-frequency welding, wherein high-frequency welding is preferred.

[0094] As an alternative or in addition to welding, adhesive may be applied to the cardboard insert before attaching it to the container body 2 .

[0095] The pressing tool 27 includes a base plate 49, which includes or is composed of a rigid material such as metal or a composite material, and a plunger skirt 51, which includes a resiliently deformable material such as rubber or plastic. The plunger skirt 51 is located on top of the base plate 49 so that it at least partially covers an upper surface 54 of the base plate 49, which is opposite to a lower footprint surface 53 of the base plate 49.

[0096] The footprint surface 53 is configured to face the cardboard insert during application of the cardboard insert into the container body 2. It will be appreciated that the footprint surface 53 may have any other suitable shape suitable for the cross-sectional shape of the packaging container 1 being produced.

[0097] By relative movement with respect to the base plate 49, the plunger skirt 51 can be in an unexpanded state (see Fig.11 ) and extended status (see Fig.13 ) between.

[0098] In the unexpanded state of the plunger skirt 51, the shape of the outer contour of the plunger skirt 51 corresponds to the shape of the outer contour of the base plate 49. Therefore, in the unexpanded state, the plunger skirt 51 has substantially the same footprint as the base plate 49.

[0099] In the expanded state, compared with the unexpanded state of the plunger skirt 51, see Fig.13 , the cross-sectional area (coverage) defined by the outer circumference of the plunger skirt 51 is larger.

[0100] The second end opening 6 of the container body 2 may be closed in a similar manner to the first end opening 4 .

[0101] The cardboard blanks 131a, 131b can be preformed in a separate method step using any suitable preforming device to form the cardboard blanks 131a, 131b into first cardboard inserts 12a, 12b and enable the first cardboard inserts 12a, 12b to be more easily assembled into the first end opening 4, the first cardboard inserts 12a, 12b thus obtaining most of their desired shape and any creases or crease lines before being inserted into the container body 2.

Claims

1. A method of forming a paperboard packaging container for bulk solids, the method comprising: obtaining a body blank having a first side edge and a second side edge, the body blank being made of a laminated sheet including a cardstock substrate layer; forming a container body from the body blank, the container body defining an interior compartment, the container body including a container body wall having an inner surface facing the interior compartment, an outer surface facing away from the interior compartment, and a weakened portion extending along at least a portion of a circumference of the container body, the container body including a first end having a first end opening and a second end opposite the first end having a second end opening; closing the first end opening by pressing a first paperboard insert into the first end opening to a first predetermined position relative to the container body and forming an exterior recess at the first predetermined position of the first paperboard insert, the first paperboard insert including a first central portion and a first peripheral flange portion covering the first end opening; attaching the first peripheral flange portion of the first paperboard insert to the container body wall at a first attachment portion of the container body, the weakened portion in the container body wall being between the first attachment portion and the second end of the container body; pressing a second paperboard insert into the exterior recess through the first end opening to a second predetermined position relative to the container body, the second paperboard insert including a second central portion covering the first end opening and a second peripheral flange portion; as well as Attaching the second peripheral flange portion of the second paperboard insert to the container body wall.

2. The method according to claim 1, wherein: The first peripheral flange portion extends away from the first central portion toward the first end opening of the container, and the second peripheral flange portion extends away from the second central portion toward the first end opening of the container body.

3. The method of claim 1 further comprising deforming the second central portion of the second paperboard insert prior to attaching the second peripheral flange portion to the container body wall such that a recessed portion of the second paperboard insert is formed adjacent the second peripheral flange.

4. The method according to claim 3, wherein: The recessed portion is shaped such that a distance between the second central portion of the second paperboard insert and the first central portion of the first paperboard insert decreases at the recessed portion.

5. The method according to claim 4, wherein: Pressing the second cardboard insert into the external recess includes positioning the second cardboard insert into the external recess using a footprint surface of a pressing tool, the footprint surface having a shape and size adapted to the shape and size of the first end opening of the container body and having a protrusion for forming the recessed portion of the second cardboard insert.

6. The method according to claim 5, wherein: Pressing the second cardboard insert into the external recess includes: positioning a guide plate adjacent to the first end opening of the container body so that a through cavity of the guide plate is aligned with the first end opening, the through cavity having a shape and size corresponding to the shape and size of the first end opening of the container body, guiding the second cardboard insert into the external recess through the through cavity of the guide plate, and forming the second peripheral flange portion between the guide plate and the pressing tool.

7. The method according to claim 6, wherein: The through cavity of the guide plate has a recessed portion extending the through cavity transversely relative to an insertion direction, and the second cardboard insert is inserted into the external recess along the insertion direction. When the pressing tool passes through the through cavity, the recessed portion of the through cavity is positioned adjacent to the protrusion on the surface of the covering area.

8. The method according to claim 6, wherein: The concave portion of the through cavity has a dovetail shape.

9. The method according to claim 8, wherein: The protrusion of the footprint surface includes an outer surface portion facing the container body wall when the pressing tool is inserted into the outer recess, the outer surface portion having a shape corresponding to a shape of an adjacent portion of the container body wall.

10. The method according to claim 9, wherein: The width of the opening of the recessed portion corresponds to the width of the outer surface portion of the protrusion of the footprint surface.

11. The method according to claim 1, wherein: The second predetermined position is located above the first predetermined position.

12. The method of claim 1, further comprising closing the second end opening at the second end.

13. A paperboard packaging container for bulk solids, the container comprising a container body defining an interior compartment, the container body comprising a container body wall made of a laminated sheet material, the laminated sheet material comprising a cardstock substrate layer, and the container body comprising a first end having a first end opening and a second end opposite the first end having a second end opening, The container body wall has an inner surface facing the inner compartment and an outer surface facing away from the inner compartment, a first cardboard insert that closes the first end opening, the first cardboard insert comprising a first central portion covering the first end opening and a first peripheral flange portion, the first cardboard insert being located in the container body and forming an exterior recess, the first peripheral flange portion being attached to the inner surface of the container body wall at a first attachment portion of the container body, The container body has a weakened portion extending along at least a portion of a circumference of the container body, the weakened portion being located between the first attachment portion and the second end of the container body, The packaging container also includes a second paperboard insert positioned in the exterior recess and covering the first end opening, the second paperboard insert including a second central portion attached to the container body wall and a second peripheral flange portion.

14. The paperboard packaging container according to claim 13, wherein: The first peripheral flange portion extends away from the first central portion toward the first end opening of the container, and the second peripheral flange portion extends away from the second central portion toward the first end opening of the container body.

15. The paperboard packaging container according to claim 13, wherein: The second central portion of the second paperboard insert includes a recessed portion adjacent to the container body wall.

16. The paperboard packaging container according to claim 14, wherein: The recessed portion is shaped such that a distance between the second central portion of the second paperboard insert and the first central portion of the first paperboard insert decreases at the recessed portion.

17. The paperboard packaging container according to claim 14, wherein: The second cardboard insert is formed by a cardboard blank, wherein the cardboard blank includes a central portion having a shape and size corresponding to the shape and size of the first end opening of the container body, and a peripheral portion surrounding the central portion, wherein the peripheral portion of the cardboard blank is enlarged adjacent to a portion of the cardboard blank where the recessed portion is formed.

18. The paperboard packaging container according to claim 13, wherein: The second central portion of the second paperboard insert includes a grip opening.

19. The paperboard packaging container of claim 18, further comprising a cover covering the grip opening.

20. The paperboard packaging container according to claim 19, wherein: The cover is a portion of the second central portion that is integrally formed with the second paperboard insert and is at least partially surrounded by the perforations of the second central portion.

21. The paperboard packaging container according to claim 19, wherein: The cover is hingedly connected to the second paperboard insert by a hinge.

22. The paperboard packaging container according to claim 13, wherein: The first paperboard insert is positioned at a first position in the container body, and the second paperboard insert is positioned at a second position in the container body, the second position being above the first position.

23. The paperboard packaging container according to claim 13, wherein: The first paperboard insert and the second paperboard insert include a cover.

24. The paperboard packaging container according to claim 23, wherein: The lid includes an upper portion of the container body, and the upper portion is separable from the container body at the weakened portion.

25. The paperboard packaging container according to claim 24, wherein: The lid is at least partially removable from the container body at the weakened portion.

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