Moulding tool for producing a packaging container

Abstract

The invention relates to a moulding tool (1000), in particular a thermoforming tool (1000), comprising a mould bottom (130) and a mould insert (140). The mould bottom (130) and the mould insert (140) define a mould cavity (160) designed to form a packaging container (1) with a hollow bottom (3). The moulding tool (1000) has at least one undercut element (134) for forming at least one undercut in the hollow bottom (3). The invention further relates to the use of the moulding tool (1000) and to a moulding machine, in particular a thermoforming machine, which comprises the moulding tool (1000). The invention further relates to a method for producing a packaging container (1) from a two-dimensional layer of material using the moulding tool (1000).

Description

[0001] Mold for producing a packaging container

[0002] Technical area

[0003] The present invention relates to a molding tool for forming a packaging container with a hollow base and at least one undercut formed in the hollow base. Furthermore, the present invention comprises a molding machine comprising the molding tool and a method for producing a container with a hollow base and an undercut arranged in the hollow base.

[0004] State of the art

[0005] Forming tools, in particular thermoforming tools, are known from the prior art. These tools are designed to transform two-dimensional material layers, such as material sheets or unrollable material webs, into three-dimensional packaging containers. Such packaging containers can be in the form of cups, bowls, or capsules and are used, for example, in food packaging. Plastic (e.g., polyethylene terephthalate (PET), polystyrene (PS), or polypropylene (PP)) is preferably used as the material for the material layers. However, the use of other formable materials, in particular formable, recyclable materials, is also conceivable.

[0006] EP 1 163 996 B1 discloses a thermoforming tool designed for producing a packaging container with a hollow base. The thermoforming tool comprises a mold insert having a mold cavity (molding space), and a two-part mold base movably received in the mold insert. Near the mold base, the mold insert has a projection that projects into the mold cavity and runs in the circumferential direction of the mold cavity. The two-part mold base has an inner base element (see Figure 2 of EP 1 163 996 B1, element 33) and a base ring element surrounding the inner base element (referred to as sealing tulip 35 in EP 1 163 996 B1). During the molding process, the preformed material layer resting against the mold base is turned inward by axially lifting the two-part mold base.By inverting the material layer, a web is created at the transition between the base area and the wall of the packaging container, which serves as the base for the container. As the two-part mold base is extended axially into the mold cavity, the base ring element is also moved against the projection of the mold insert, whereby the two material layer walls of the web are squeezed together. The projection protruding into the mold cavity, which is intended to squeeze the web walls, creates a pronounced indentation (undercut) in the container side wall immediately above the web, running in the circumferential direction of the container. This indentation can be disruptive in two ways. Firstly, the container is difficult to demold in the area of ​​the indentation; secondly, the indentation leads to an uneven outer surface.However, uneven outer surfaces can lead to restrictions when applying product information, in particular making direct printing on the outer surface of packaging containers more difficult, as this requires outer surfaces that are as flat as possible without undercuts, steps, ribs or other uneven wall structures.

[0007] Furthermore, DE 10 2020 118 217 A1 discloses a thermoforming tool designed to form a packaging container with undercuts formed in the container side wall. Such undercuts in the region of the container side wall can serve for container stacking and / or for reinforcing the container side wall. Undercuts used for stacking are preferably formed near the container opening (so-called top stackers) and / or near the container bottom (so-called bottom stackers). Undercuts designed for stacking are generally very pronounced and result in stepped side walls. As already described above, side walls with undercuts, ribs, or other structures are disadvantageous when applying product information. This is particularly true when product information is printed directly on the outer surface of packaging containers.It is therefore an object of the present invention to provide a molding tool and a molding method which are designed to produce packaging containers which have an outer surface which is as flat as possible and yet are stable and easy to stack.

[0008] Brief outline

[0009] To achieve at least the above-mentioned object, according to a first aspect of the invention, a molding tool, in particular a thermoforming tool, is provided, comprising a mold base and a mold insert, wherein the mold base and the mold insert define a mold cavity provided for forming a packaging container with a hollow base; the molding tool further comprises at least one undercut element configured to form at least one undercut in the hollow base.

[0010] The mold cavity is formed in the mold insert. The mold cavity is delimited in the radial direction by an inner wall of the mold insert, which runs circumferentially around the mold cavity. The mold cavity is further delimited in the axial direction by the mold base. For this purpose, the mold base can be arranged at a first axial end of the mold insert or slidably received in the mold insert at the first axial end. At the opposite, second axial end, the mold insert or the mold cavity formed in the mold insert is open. Thus, a two-dimensional material layer can be molded into the mold cavity via the opening and thus formed into a three-dimensional packaging container. The molding process is described in more detail below in connection with a molding method according to the invention.

[0011] A hollow base refers to a container base that has an inner base region and a web arranged radially further outwards that surrounds the inner base region. The bottom wall of the inner base region is offset axially inwards (i.e., towards the container interior) with respect to the web region. Thus, the packaging container, which is placed on a support plate, such as a horizontal table top, rests on the support plate only with its axially projecting web. The web thus functions as the base for the packaging container. In contrast, the axially recessed inner base region does not touch the support plate; rather, a cavity forms between the support plate and the bottom wall of the inner base region.

[0012] Overall, the shape of the packaging container is determined by the shape (geometry) of the mold cavity. The shape (geometry) of the mold cavity is, in turn, determined by the mold base and the inner wall of the mold insert. In particular, the packaging container and the mold cavity producing the packaging container can be rotationally symmetrical, with a rotation axis that runs essentially perpendicularly through the center of the mold base (container base). For example, the packaging container formed with the molding tool can be a cup, a bowl, a capsule, or another rotationally symmetrical hollow body with a hollow base.

[0013] In the following, "axial direction" means a direction parallel to the axis of rotation; similarly, "axial movement" or "axially movable" means a movement along the axis of rotation; furthermore, "radial direction" means a direction perpendicular to the axis of rotation; similarly, "radial movement" or "radially movable" means a movement in a direction perpendicular to the axis of rotation.

[0014] Any two-dimensional (sheet-like) material layer can be used as a material layer that can be formed into a three-dimensional packaging container by applying a forming force in the mold. The forming force can be provided, for example, by a forming punch or pre-stretcher that can be moved into the mold cavity, by introducing compressed air (also called forming air) into the mold cavity, and / or by applying a vacuum to the mold cavity. To assist the forming process, the material layer can also be heated.

[0015] The material layer can be fed into the mold either as a rollable material web or as a cut sheet of material. Thermoplastic materials such as polystyrene (PS), polypropylene (PP), or polyethylene terephthalate (PET) can be used as the material layer. However, material layers made of natural fibers or other recyclable materials or biomaterials are also conceivable. These materials can be molded into the mold cavity of the mold by applying pressure (vacuum) and / or temperature, and can be formed into the desired packaging container.

[0016] The at least one undercut element of the molding tool is designed to create at least one undercut in the hollow base. In particular, the at least one undercut element can be designed to create at least one undercut in the hollow base of the packaging container, which can be used as a stacking shoulder (stacking support) for stacking packaging containers of the same shape.

[0017] To create the at least one undercut in the hollow base, the at least one undercut element can be arranged radially spaced from the mold insert in the molding tool. In particular, the at least one undercut element can be arranged radially spaced from the mold insert on or near the mold base of the molding tool. In other words, the at least one undercut element can have a (predetermined) radial distance from the inner wall of the mold insert. In particular, the at least one undercut element can be arranged concentrically to the mold insert in the molding tool. The described arrangement of the at least one undercut element in the molding tool enables the creation of at least one undercut (stacking shoulder) in the base region of the packaging container. Thus, the formation of a stacking shoulder on the side wall of the packaging container can be omitted, whereby the side wall can be designed much more flat (uniform).

[0018] In order to be able to use the at least one undercut created in the hollow base of the packaging container as a stacking shoulder, it is further advantageous to design the at least one undercut element such that it extends in the circumferential direction of the mold base. According to one variant, the at least one undercut element can consist of one element that extends in the circumferential direction of the mold base. As a result, an undercut (stacking shoulder) that is continuous in the circumferential direction of the hollow base can be created in the hollow base in a structurally simple manner. According to another variant, the at least one undercut element can consist of several elements (for example two, three, four or more elements) that extend in the circumferential direction. The several elements can be arranged directly adjacent to one another in the circumferential direction.In this case, too, a continuous undercut (stacking shoulder) can be created in the hollow base in the circumferential direction of the hollow base. Alternatively, the multiple elements can be arranged spaced apart from one another in the circumferential direction, creating several spaced-apart undercuts in the circumferential direction in the hollow base of the packaging container. The multiple undercuts can together form a stacking support, thus enabling secure stacking with this design as well.

[0019] Furthermore, it can be advantageous for the at least one undercut element to have a side wall facing the mold insert or the inner wall of the mold insert; this side wall can be inclined outwards towards the mold insert or the inner wall of the mold insert. The outwardly inclined side wall can run essentially concentrically to the inner wall of the mold insert in the circumferential direction. The side wall of the undercut element is thus also inclined towards the mold base; the angle of inclination formed by the mold base and the inclined side wall of the at least one ring element is less than 90°. The described design of the undercut element with an outwardly inclined side wall can thus create a distinctive undercut in the base region of the packaging container, which can be used as a stacking support.

[0020] Furthermore, the at least one undercut element can be arranged so as to be axially movable (i.e., movable in the axial direction of the molding tool). In particular, the at least one undercut element can be arranged so as to be axially movable on the mold base or in the vicinity of the mold base. The at least one axially movable undercut element can be movable back and forth between an axially disengaged molding position and an engaged starting position; in the disengaged position, the at least one undercut element can be moved axially into the mold insert by a predetermined amount to enable the formation of the at least one undercut in the hollow base of the packaging container. In the engaged position, the at least one undercut element can be moved back to the axial starting position.

[0021] In addition, the at least one axially movable undercut element can be arranged radially movable (i.e. movable in the radial direction of the molding tool) in the molding tool. In particular, the at least one undercut element can be arranged radially movable on the mold base or in the vicinity of the mold base. To form the undercut in the hollow base, the at least one undercut element can be moved radially outwards (i.e. in the direction of the inner wall of the mold insert). To demold the undercut, the undercut element can be moved radially inwards again into an initial position. This radial movement of the undercut element can, on the one hand, form a pronounced undercut in the hollow base of the packaging container to be produced, which can be used as a stacking shoulder or stacking support for stacking packaging containers of the same shape.On the other hand, the radial return movement to the starting position can support demoulding in the area of ​​the created undercut.

[0022] Alternatively, the at least one undercut element can be arranged axially immovably in the molding tool. In particular, the at least one undercut element can be arranged axially immovably on the mold base of the molding tool and protrude into the mold insert. In this variant, too, in a further development, the at least one undercut element can be designed to be movable in the radial direction and can be moved back and forth between a first radial position and a second radial position, as described above in connection with the axially displaceable undercut element.

[0023] Furthermore, the at least one undercut element can be implemented as part of the mold base. In particular, the mold base of the molding tool can have a base element arranged in the center (hereinafter referred to as the centric base element) and an annular base element surrounding the centric base element (hereinafter referred to as the base ring element). The base ring element can be fixedly (stationarily) arranged or mounted in the molding tool. For example, the base ring element can be fastened to the mold insert or formed integrally therewith. Furthermore, the at least one undercut element can be arranged between the centric base element and the base ring element. In other words, the at least one undercut element can be arranged at the transition between the centric base element and the base ring element.As described above, the at least one undercut element can extend in the circumferential direction of the mold base and have an outer surface inclined outwards towards the mold insert or the inner wall of the mold insert.

[0024] According to a first implementation variant, the centric base element and the at least one undercut element can be arranged or mounted in the molding tool so as to be axially movable. In particular, during a molding process, the centric base element and the at least one undercut element can be moved (raised) in the axial direction by a desired amount into the mold cavity. This creates an annular gap (hereinafter referred to as the annular gap) in the region of the stationary (immovable) base ring element, the outer wall of which is formed by an inner wall section of the mold insert and the inner wall of which is formed by the outwardly inclined side wall of the at least one undercut element.

[0025] Due to the axial movement of the central base element and the at least one undercut element in the direction of the mold cavity, the material layer formed into the mold insert and resting against the mold base is turned inside out. Furthermore, the material layer (material layer section) formed into the temporarily created annular gap comes into contact with the base ring element, the inner wall section of the mold insert, and the outwardly inclined side wall of the at least one undercut element. This creates a web that surrounds the turned-over base in the region of the central base element and projects axially (downward). Furthermore, the web outer wall has the shape (and inclination) of the inner wall section of the mold insert immediately adjacent to the base ring element; the web inner wall, in contrast, has the shape (and inclination) of the outwardly inclined side wall of the at least one undercut element.In other words, the inner web wall has essentially the same inclination as the side wall of the at least one undercut element. The inner web wall is thus designed to be inclined outwards, so that an undercut is created on the inner web wall and a shoulder (stacking shoulder) is created at the transition between the inner web wall and the (turned over) inner base region, which shoulder can be used for container stacking. The outer web wall, on the other hand, has the inclination of the inner wall section of the mold insert immediately adjacent to the base ring element. This inner wall section preferably has the same wall inclination as the remaining inner wall of the mold insert that bounds the mold cavity. This makes it possible to produce a packaging container with a flat side wall and a uniform wall inclination from the container edge to the base of the web, which is advantageous if the packaging container is to be printed with information.

[0026] If, furthermore, the at least one undercut element is additionally mounted for radial displacement, the width of the annular gap and thus the width of the web formed in the molded packaging container can be further adjusted. According to one variant, the at least one undercut element can be moved radially outward until the web inner wall resting against the side wall of the at least one undercut element is pressed against the web outer wall resting against the inner wall section. This creates a double-walled web without a gap, similar to that described in EP 1 163 996 B1. The shape of the web produced, however, is quite different and differs primarily in that an undercut is formed on the web inner wall and a shoulder (stacking shoulder) is formed at the transition between the web inner wall and the base inner region, and the web outer wall transitions essentially seamlessly into the side wall of the packaging container.

[0027] Since in the first implementation variant described above the centric base element and the at least one undercut element are moved together in the axial direction, the at least one undercut element can be mounted on the centric base element. This allows the tool to be simplified in terms of construction, since only the centric base element needs to be moved (actuated) in the axial direction and the at least one undercut element moves axially with the centric base element. Alternatively, the undercut element can be mounted in the mold and moved (actuated) axially independently of the centric base element. According to a second implementation variant, the at least one undercut element can be arranged in a fixed (stationary) position on the annular base element (base ring element). In this implementation variant, only the centric base element can be arranged so as to be axially movable in the mold.In this implementation variant, too, the at least one undercut element can extend in the circumferential direction of the mold base and be arranged concentrically to the mold insert or the inner wall of the mold insert, as described above. Furthermore, the at least one undercut element can protrude from the base ring element into the mold cavity and have a side wall that is inclined towards the mold insert or the inner wall of the mold insert, as described above. In this implementation variant, a permanent annular gap is created, the outer wall of which is formed by the inner wall section of the mold insert adjacent to the base ring element and the inner wall of which is formed by the outwardly inclined side wall of the at least one undercut element.

[0028] During the molding process, the material layer is molded into the annular gap using molding air, forming the container web with an inner web wall that essentially has the inclination of the side wall of the at least one undercut element, and an outer web wall that essentially has the inclination of the inner wall or the inner wall section of the mold insert. The inner web wall is inclined outwardly due to the outwardly inclined side wall of the at least one undercut element, creating an undercut on the inner web wall and a support shoulder at the transition between the inner web wall and the inner base region of the packaging container, as described above.

[0029] The molding tool may further comprise an axial actuation mechanism configured to move the centric base element and / or the at least one undercut element in the axial direction, as described above. The axial actuation mechanism may be implemented in the form of a pneumatic actuation mechanism (e.g., a cylinder-piston arrangement) or in the form of an electromechanical actuation mechanism. For example, the pneumatic or electromechanical actuation mechanism may be configured to axially move (raise or lower) an ejector bar of the molding tool, which can transmit the movement to the centric base element via an ejector rod.

[0030] If the at least one undercut element is additionally mounted for radial movement, the molding tool can further comprise a radial actuation mechanism designed to move the at least one undercut element radially, as described above. The radial actuation mechanism can also be pneumatic (in the form of a cylinder-piston arrangement) or electromechanical. A particularly simple design of a radial actuation mechanism can be achieved by using a mechanical pivoting mechanism designed to translate the axial movement of the central base element or the ejector rod into a corresponding radial movement for the at least one undercut element.

[0031] The axial and / or radial actuating mechanisms described here can be controlled accordingly in accordance with the present invention via a control unit of a molding machine in which the molding tool is installed.

[0032] The mold insert can also have a flat inner wall. A flat inner wall can mean an inner wall that has no undercuts, protrusions, indentations, or other structures. This allows the packaging container to have a flat side wall that is suitable for direct printing.

[0033] In particular, the inner wall can be designed to taper conically in the axial direction towards the mold base. For example, the inner wall of the mold insert can have a side wall angle which is in the range from 1° to 40°, preferably in the range from 1° to 15°. The side wall angle means the angle of inclination in a sectional plane parallel to the axis of rotation of the mold insert, which angle is subtended by the inner wall tapering towards the base and the axis of rotation. The mold insert and mold base described here for forming the mold cavity can be part of a first tool part of the mold. Furthermore, the mold can have a second tool part which interacts with the first tool part. The second tool part can accommodate, for example, a forming punch or pre-stretcher which is designed to form or pre-stretch the material layer to be formed into the mold cavity.Furthermore, a hold-down device can be provided in the second tool part to hold down the material layer during the forming process. Preferably, the first tool part is a lower tool and the second tool part is an upper tool. However, the reverse arrangement is also conceivable, in which the first tool part is an upper tool and the second tool part is a lower tool.

[0034] The mold described here has a mold cavity. Alternatively, the mold can be designed as a multiple mold having a plurality (at least two) mold inserts, each of the plurality of mold inserts having a mold cavity and a mold base with the properties described above.

[0035] According to a second aspect of the invention, a forming tool, in particular a thermoforming tool, is described which is designed to produce a packaging container with a side wall and with a hollow base, wherein the hollow base has an undercut and wherein the side wall has a flat outer surface.

[0036] The at least one undercut can be formed in the hollow base such that it forms a stacking support for packaging containers of the same shape. In particular, the at least one undercut can be formed on a container web, in particular on an inner wall of the container web. By forming the at least one undercut on the inner wall of the container web, a stacking shoulder (stacking support) can be created at the transition between the web and the hollow base. As a result, the side wall of the packaging container can be completely flat (i.e., without steps and / or undercuts). In particular, the outer surface of the packaging container can be completely flat. Thus, the outer surface of the packaging container can be continuously (fully) printed.According to a third aspect of the invention, the above-mentioned molding tool is used to produce a packaging container with a hollow base and at least one undercut formed in the hollow base from a two-dimensional material layer. The undercut formed in the hollow base can function as a stacking support (stacking shoulder). Thus, the packaging containers produced with the aid of the above-described molding tool can be stacked on the stacking support formed in the hollow base. In particular, the packaging containers produced with the aid of the above-described molding tool can have a side wall with a flat outer surface that can be directly and completely printed.

[0037] According to a fourth aspect of the invention, a molding machine, in particular a thermoforming machine, is provided, which accommodates the above-described molding tool (thermoforming tool). The molding machine, in particular a thermoforming machine, can have a machine table for accommodating the molding tool. In particular, the thermoforming machine can have a lower machine table for accommodating the first tool part with the above-described properties and an upper machine table for accommodating the second tool part with the above-described properties.

[0038] According to a fifth aspect of the invention, a method for producing a packaging container from a sheet-like material layer is provided, wherein the method is carried out using the molding tool described above. The method comprises the following steps: feeding a material layer to the molding tool; forming the material layer into a packaging container with a hollow base and at least one undercut formed in the hollow base by forming the material layer into the mold cavity of the molding tool at least by applying molding air (compressed air) and / or a vacuum until the material layer comes into contact with the mold base with the at least one undercut element and the inner wall of the mold insert; and demolding the packaging container formed in the mold cavity by axially moving at least a portion of the mold base. The forming step may further comprise pre-stretching the material layer into the mold cavity.This step can be performed using a mechanical pre-stretcher located in the mold. The pre-stretched material layer can then be fully formed into the desired packaging container in the mold cavity using forming air (compressed air) and / or vacuum.

[0039] The at least one undercut element can be arranged between the centric base element and the annular base element (base ring element) surrounding the centric base element. Furthermore, if the at least one undercut element and the centric base element are arranged axially displaceably (movably) with respect to the base ring element in the mold, the molding step can comprise the following substeps: axially displacing (moving) the centric base element and the at least one undercut element in the direction of the mold cavity in order to turn over the material layer resting on the mold base and form a container web with at least one undercut in the region of the base ring element. In this molding variant, the material layer is turned over in the base region and further formed into the annular gap temporarily formed in the base ring region by axial displacement (movement) of the centric base element and the undercut element.

[0040] Furthermore, if the at least one undercut element is arranged radially displaceably (movably) in the mold, the molding step may further comprise: radially displacing (moving) the at least one undercut element outward (toward the mold insert) to press the inner wall of the web against the outer wall of the container web formed in the base ring element. This allows a gap-free web to be formed.

[0041] The demolding step may further comprise the following substeps: radially displacing (moving) the at least one undercut element inward into its starting position in order to demold the container web with the at least one undercut; and further axially displacing (moving) the central base element in the direction of the mold cavity in order to completely demold (and eject) the container. According to an alternative molding variant, the at least one undercut element may be arranged between the central base element and the annular base element (base ring element) surrounding the central base element; furthermore, the at least one undercut element may be arranged in a fixed position on the base ring element and form a (permanent) annular gap with the base ring element. The molding step may then comprise molding the material layer into the annular gap in order to form a container web with at least one undercut.In this mold variant, the annular gap is permanently formed in the mold base, and the material layer is formed into the annular gap with the aid of molding air. There is no inversion of the material layer in the area of ​​the central base element and the undercut element, as in the first mold variant.

[0042] In this second variant, the demolding step may further comprise axially displacing (moving) the centric base element toward the mold cavity to completely demold (and eject) the container.

[0043] Short description of the drawings

[0044] Further details and advantages of the invention are explained with reference to the following drawings. They show:

[0045] Figure 1 is a view of a molding tool according to the present invention;

[0046] Figures 2a / 2b enlarged views of the mold according to Figure 1;

[0047] Figures 3a - 3e show views of another mold according to the present

[0048] Invention during a molding cycle;

[0049] Figures 4a - 4d show views of a packaging container produced using the molding tool according to Figures 3a to 3e; Figure 5 shows a flow chart illustrating a method according to the invention for producing a packaging container with a hollow base and an undercut formed in the hollow base.

[0050] Detailed description

[0051] Molding tools according to the invention are further described below by way of example. It should be understood that the description of these embodiments serves to better understand the invention and that the invention is not intended to be limited to these specific molding tools.

[0052] A first molding tool 1000 according to the invention is described in conjunction with Figure 1 and Figures 2a and 2b. Figure 1 shows a sectional view of the molding tool 1000, while Figures 2a and 2b show enlarged sections of the molding tool 1000 of Figure 1.

[0053] First, Figure 1 is described, in which the molding tool 1000 is designed as a thermoforming tool. Furthermore, the thermoforming tool 1000 can be designed as a multi-cavity thermoforming tool having a plurality of mold cavities 160 for forming a plurality of packaging containers with a hollow bottom and an undercut formed in the hollow bottom. The packaging containers produced can be cups, trays, or capsules. The geometry (shape) of the produced packaging containers is determined by the geometry (shape) of the mold cavities 160.

[0054] In Figure 1, five mold cavities 160 are indicated by way of example, although it should be clear that the present invention does not depend on the specific number of mold cavities 160. Rather, the thermoforming tool 1000 can also have more than five mold cavities 160 or even just a single mold cavity 160. The thermoforming tool 1000 is further described below with reference to one mold cavity 160. The following singular formulations of corresponding components of the thermoforming tool 1000 also encompass a plurality of these components, which can be arranged next to one another (for example, in a matrix mold) in a multiple thermoforming tool.

[0055] The thermoforming tool 1000 comprises a first tool part 100 and a second tool part 200, which are arranged opposite one another in the axial direction (in the vertical direction) and movable relative to one another. The first tool part 100 is designed as the lower tool part 100 (also called the lower tool); correspondingly, the second tool part 200 is designed as the upper tool part 200 (also called the upper tool).

[0056] The first tool part 100 has a mold insert 140 with a mold cavity 160. The mold cavity 160 is delimited by an inner wall 142 of the mold insert 140. The shape of the mold cavity 160 determines the shape of the packaging container to be produced. In particular, the mold cavity 160 can be rotationally symmetrical, and the inner wall 142 can surround the mold cavity 160 in the circumferential direction. The inner wall 142 of the mold insert 140 can further be tapered in the axial direction toward the mold base 130, thereby creating a typical cup shape. Preferably, the inner wall 142 is flat and has no indentations, projections, or undercuts; this allows packaging containers with a flat side wall to be produced.

[0057] The mold insert 140 is embedded in a cooling block 120. The cooling block 120 and the mold insert 140 accommodated therein are mounted on a first tool carrier 110 of the first tool part 100.

[0058] A mold base 130 is arranged at the axially lower end of the mold insert 140. The mold base 130 has a centrally arranged base element 132 (hereinafter also referred to as the central base element 132) and an annular base element 136 (hereinafter also referred to as the base ring element 136) surrounding the central base element 132. At least one undercut element 134 is arranged between the central base element 132 and the base ring element 136. The nature of the mold base 130 is described in more detail below in connection with Figures 2a and 2b.

[0059] The first tool part 100 further comprises an ejector bar 152, which is coupled to the central base element 132 via an ejector rod 150. The ejector bar 152 is operable, in particular movable in the axial direction. For example, the ejector bar 152 and the ejector rod 150 coupled thereto can be raised axially (i.e., moved toward the second tool part 200), whereby the central base element 132 is moved into the mold cavity 160 (for example, into an ejection position as shown in Figure 2a). Likewise, the ejector bar 152 and the ejector rod 150 coupled thereto can be lowered axially (moved away from the second tool part 200), whereby the central base element 132 is moved back to its starting position (for example, molding position) (see Figure 2a).

[0060] The second tool part 200 (upper tool 200) has a block-shaped upper tool carrier 210. A recess 240 is provided therein for receiving a hold-down device 220. The hold-down device 220 is provided for holding down the material layer during a thermoforming process. Furthermore, the second tool part 200 has a pre-stretcher 232, which is received in a recess of the hold-down device 220 and is movable in the axial direction. For this purpose, the pre-stretcher 232 is coupled to a pre-stretcher rod 234. The pre-stretcher rod 234 is in turn coupled to a pre-stretcher plate 236. The pre-stretcher plate 236 is actuable in the axial direction; in particular, it can be axially lowered (i.e., moved toward the first tool part 100) or axially raised (i.e., moved away from the first tool part 100).For example, the pre-stretch plate 236 and the pre-stretch rod 234 coupled thereto can be lowered axially, whereby the pre-stretcher 232 is moved into the mold cavity 160. As a result, a material layer arranged between the first tool part 100 and the second tool part 200 (not shown in Figure 1) can be pre-stretched into the corresponding mold cavity 160. In Figure 1, the thermoforming tool 1000 is shown in the closed state, i.e., the two tool parts 100 and 200 are moved towards one another, so that a material layer arranged between the two tool parts 100 and 200 is held down (clamped) by the hold-down device 220. In the closed state, the material layer can be stretched or pre-stretched into the corresponding mold cavity 160 by disengaging (lowering) the pre-stretcher 232. This creates preformed moldings which, however, do not yet have the final shape of the packaging container.

[0061] For complete molding, molding air (compressed air) can be introduced into the mold cavity 160 via channels (not shown in Figure 1). The introduced molding air presses the pre-stretched material layer against the inner wall 142 of the mold insert 140 and the mold base 130, giving the molded article its final shape. By contacting the heated film with the inner wall 142 of the mold insert 140 and the mold base 130, the molded material layer is cooled, creating a stable packaging container.

[0062] The thermoforming tool 1000 can then be vented. This releases the molding air introduced into the mold cavity 160. The thermoforming tool 1000 is then opened; the two tool parts 100 and 200 are moved apart again. By lifting the central base element 130 with the aid of the ejector rod 150 and the ejector bar 152, the packaging article can be ejected from the mold cavity 160 (indicated in Figure 2b).

[0063] In connection with Figures 2a and 2b, the mold base 130 of the thermoforming tool 1000 and the undercut formation in the base area are further described.

[0064] The mold base 130 has the central base element 132 and the outermost base ring element 136, as described above. The central base element 132 is mounted for axial movement and can be lifted with the aid of the ejector bar 152 and the ejector rod 150 and thus moved in the direction of the mold cavity 160. The base ring element 136, however, is fixedly arranged on the mold insert 140 at the axially lower end. According to one variant, the base ring element 136 can form a unit with the mold insert 140 (i.e., be formed in one piece). The base ring element 136 is thus arranged stationary (non-movable) in the thermoforming tool 1000.

[0065] The at least one undercut element 134 is arranged between the base ring element 136 and the central base element 132. The at least one undercut element 134 is essentially designed as a ring element that is arranged (immediately adjacent) to the central base element 132 and surrounds the central base element 132 in the circumferential direction. The annular undercut element 134 is continuous in the circumferential direction. However, a design is also conceivable in which the annular undercut element 134 consists of several segments that are arranged directly adjacent to one another or spaced apart from one another in the circumferential direction.

[0066] As further shown in Figures 2a and 2b, the annular undercut element 134 is fixedly arranged at the radially inner end of the base ring element 136. Starting from the base ring element 136, the undercut element 134 extends axially into the mold cavity 160. This creates a circumferentially extending (permanent) gap 138 (also called an annular gap) between the undercut element 134 and the inner wall 142 of the mold insert 140 in the region of the base ring element 136. During a molding process, the material layer is molded (with the aid of molding air) into the annular gap 138, creating a web in the base region of the packaging container.

[0067] As further shown in Figures 2a and 2b, the undercut element 134 has a side wall 134a facing the mold insert 140 or the inner wall 142 of the mold insert 140, which is inclined radially outward. This outwardly inclined side wall 134a forms the inner wall of the annular gap 138, whereas the outer wall of the annular gap 138 is formed by the inner wall 142 or an inner wall section of the mold insert 140. The pronounced outward inclination of the side wall 134a of the undercut element 134 creates an annular gap 138 with an undercut 134b; furthermore, a radially outwardly projecting shoulder 134c is formed at the transition from the side wall 134a of the undercut element 134 to the central base element 132 (see Figure 2a).

[0068] As can also be seen from Figure 2a, in the molding position, the position of the central base element 132 is coordinated in the axial direction with the undercut element 134 projecting into the mold cavity 160. In the molding position, the central base element 132 projects into the mold cavity 160 by approximately the same amount as the undercut element 134. This creates the structure of a hollow base, with the transition between the undercut element 134 and the central base element 132 preferably being substantially continuous.

[0069] The shape of the hollow base 130 described here, with annular gap 138, undercut 134b, and radially projecting shoulder 134c, is transferred to the formed packaging container during the forming process. The described thermoforming tool 1000 can thus be used to produce packaging containers that have a hollow base with a web defining the hollow base and a circumferentially extending undercut on the inner wall of the web. The undercut forms a shoulder at the transition from the inner wall of the web to the inner area of ​​the base, which shoulder can be used as a stacking shoulder. Furthermore, since the inner wall 142 of the mold insert 140 is flat, the packaging containers formed with the thermoforming tool 1000 have a flat container side wall.

[0070] Figure 2b shows the thermoforming tool 1000 in the open state, more precisely, in a demolding position. To demold a packaging container formed in the mold cavity 160, the central base element 132 is moved upward with the aid of the ejector bar 152 and the ejector rod 150. As a result, the molded container (not shown in Figure 2b) is demolded from the inner wall 142 of the mold cavity 160 and the mold base 130. The packaging container has a certain degree of flexibility, so that the container can be reliably demolded even in the region of the annular gap 138 with undercut 134b. A further thermoforming tool 1000a according to the present invention is described in conjunction with Figures 3a to 3e. The thermoforming tool 1000a according to Figures 3a to 3e differs from the thermoforming tool 1000 according to Figures 2a and 2b essentially in the first tool part 100 (lower tool).The second tool part 200 (upper tool) is identical to the thermoforming tool 1000 shown in Figures 1, 2a, and 2b. Reference is made to the above description.

[0071] Figures 3a to 3e again show an enlarged section of the first tool part 100, with only one mold cavity 160 visible. The mold cavity 160 is again defined by a mold insert 140 and by a mold base 130a or its inner walls. The mold cavity 160 of the thermoforming tool 1000a essentially corresponds to the mold cavity 160 of the thermoforming tool 1000 described in connection with Figures 2a and 2b. Reference is made to the above description.

[0072] The essential difference from the thermoforming tool 1000 lies in the design of the mold base 130a. This comprises a central base element 132, a base ring element 136 surrounding the central base element 132, and at least one undercut element 134 arranged therebetween.

[0073] The at least one undercut element 134 is arranged directly adjacent to the central base element 132 and surrounds the central base element 132 in the circumferential direction. Furthermore, the undercut element 134 has a side wall 134a facing the mold insert 140 or the inner wall 142 of the mold insert 140, which is inclined radially outward.

[0074] In the implementation shown in Figures 3a to 3e, the undercut element 134 is mounted on the central base element 130. This allows the undercut element 134 to be moved axially together with the central base element 132, as shown in Figure 3b. The central base element 132 can be actuated (moved axially) via an ejector rod 150 and an ejector bar 152 of the thermoforming tool 1000a, just as described above in connection with the thermoforming tool 1000.

[0075] Alternatively, it is also conceivable that the at least one undercut element 134 is mounted separately in the mold 1000a, i.e., independently of the centric base element 132. In this case, the centric base element 132 and the at least one undercut element 134 surrounding the centric base element 132 can be actuated separately in the axial direction. This implementation is more complex in terms of construction, but allows for greater flexibility in operation, since the centric base element 132 and the at least one undercut element 134 can be moved independently of one another in the axial direction.

[0076] The at least one undercut element 134 consists of at least two (preferably at least three or at least four or at least five or at least six or at least seven or at least eight or even more) elements (segments) which are arranged directly adjacent to one another in the circumferential direction and partially surround the central base element 132. An arrangement is also conceivable in which the undercut element 134 consists of at least two, preferably at least three, more preferably at least four elements (segments) which are arranged in the circumferential direction on the outer side of the central base element 132, wherein adjacent elements of the undercut element 134 do not directly adjoin one another (come into contact with one another), but are separated from one another by segments of the central base element 132.

[0077] The base ring element 136 is again designed to be stationary, as in the thermoforming tool 1000 of Figures 1, 2a, and 2b. It can be arranged at the axially lower end of the mold insert 140 and molded there, as shown in Figures 3a to 3e. In the embodiment shown, the ring element 136 is formed integrally with the mold insert 140. In conjunction with Figures 3a to 3e, the operation of the thermoforming tool 1000a will now be further described using the forming of a packaging container 1.

[0078] Figure 3a shows the thermoforming tool 1000a in the closed state, with the first tool part 100 and the second tool part 200 moving toward each other. Furthermore, the central base element 132 with the at least one undercut element 134 is in a starting position at the axially lower end of the mold cavity 160.

[0079] The material layer held down by the hold-down device 220 is formed into the mold cavity 160. This can be done with the aid of the pre-stretcher 232, which initially stretches or pre-stretches the heated material layer into the mold cavity 160. Subsequently, by applying molding air (compressed air) and / or vacuum, the material layer can be further formed into the mold cavity 160 until the material layer (fully) rests against the inner wall 142 of the mold insert 140 and the mold base 130a. This is shown in Figure 3a, where the material layer rests against the inner wall 142 of the mold insert 140 and the bottom wall of the mold base 130a. Furthermore, the pre-stretcher 232 has been retracted into its starting position.

[0080] The formation of the hollow base 3 of the packaging container 1 will now be described in connection with Figures 3b to 3e. The hollow base 3 comprises an inner base region 3a and a further outer web 3b with an undercut 3c, which surrounds the inner base region 3a.

[0081] Figure 3b shows the forming of the hollow base 3 in the packaging container 1. This occurs by axially lifting the central base element 132 together with the undercut element 134 mounted on the central base element 132 by a predetermined amount (with the aid of the ejector bar 152 and the ejector rod 150), i.e., moving it axially in the direction of the mold cavity 160. This results in the material layer in the inner base region 3a of the packaging container 1 being inverted. By lifting the central base element 132 together with the undercut element 134, a (temporarily formed) annular gap 138 is created between the inner wall 142 of the mold insert 140 and the side wall 134a of the undercut element 134 facing the mold insert 140. This annular gap 138 is formed in the region of the base ring element 136 and extends in the circumferential direction. This is shown in Figure 3b.

[0082] As can also be seen from Figure 3b, the side wall 134a of the undercut element 134 is inclined outwardly, such that the side wall 134a, together with the horizontal wall of the base ring element 136, forms an angle of less than 90°. A web 3b with an undercut 3c is thus created on the packaging container 1 in the region of the base ring element 136. The undercut 3c is created by the side wall 134a of the undercut element 134 on the web inner wall. Furthermore, an outwardly projecting shoulder 3d is formed at the transition region between the web inner wall and the base inner region 3a, which can be used as a stacking support for packaging containers of the same shape.

[0083] The packaging container 1 produced in Figure 3b thus has a hollow base 3 with an undercut 3c arranged directly in the hollow base 3. This undercut 3c is arranged in the transition area between the web 3b and the inwardly offset central base area 3a.

[0084] In an advantageous development, the at least one undercut element 134 can also be mounted on the central base element 132 in such a way that the undercut element 134 or its segments (elements) can be moved (disengaged) radially outward. This allows the width of the web 3b of the packaging container 1 to be further varied or adjusted, as further described in connection with Figures 3c to 3d.

[0085] In Figure 3c, the at least one undercut element 134 is displaced radially outward compared to the illustration in Figure 3b (see arrows in Figure 3c, which indicate this radial outward displacement). This displaces the inner wall of the web against the outer wall of the web, allowing the web width to be adjusted; in Figure 3c, the inner wall of the web is displaced against the outer wall of the web until the two web walls touch or are squeezed together. This allows a particularly robust web 3b to be formed.

[0086] To facilitate the subsequent demolding of the packaging container 1 thus produced, with a hollow base 3 and an undercut 3c arranged in the hollow base 3, the at least one undercut element 134 (or its segments) is subsequently moved back into its original position (retracted). This radial movement of the at least one undercut element is indicated by arrows in Figure 3d. This creates a circumferentially extending cavity between the side wall 134a of the undercut element 134 and the formed web 3c, which facilitates the demolding of the web 3b with the undercut 3c.

[0087] Subsequently, the centric base element 132 together with the undercut element 134 arranged on the centric base element 132 can be further lifted with the aid of the ejector rod 150 in order to enable the demolding of the produced packaging container 1 from the mold insert 140 and to eject the produced packaging container 1 (see ejection position of the centric base element 132 and the undercut element 134 in Figure 3e).

[0088] The packaging container 1 produced with the aid of Figures 3a to 3e is shown again in Figures 4a to 4d. Figures 4a and 4b show isometric views, while Figure 4c shows a sectional view and Figure 4d shows several stacked packaging containers 1. With the described thermoforming tool 1000a, it is possible to produce packaging containers 1 with a hollow base 3, wherein the stacking shoulder 3d is formed in the hollow base 3 (see Figure 4c). As can be seen in Figure 4d, the packaging containers 1 can be securely stacked, with the containers 1 resting with their web 3b on the stacking shoulder 3d of the outer container 1 formed by the undercut 3b.

[0089] Because the stacking shoulder 3d is arranged in the hollow base 3, the side wall 2 of the packaging container 1 can be flat (i.e., without steps or undercuts). As can be seen in Figures 4c and 4d, the side wall 2 of the packaging container 1 can be flat from the container edge to the web support. This not only makes the visual shape of the packaging container 1 more appealing. Furthermore, the flat outer surface of the side wall 2 makes it possible to print the packaging container 1 directly and completely.

[0090] In connection with Figure 5, a method for producing a packaging container 1 from a two-dimensional material layer is described. The method can be carried out using the molds 1000, 1000a described above.

[0091] In a first step S10 of the method, the material layer is fed to the molding tool 1000, 1000a for molding. In particular, the feeding step S10 may include heating the material layer to a desired temperature and positioning the heated material layer between the two tool parts of the molding tool 1000, 1000a. A material layer made of thermoplastic material, such as polystyrene (PS), polypropylene (PP), or polyethylene terephthalate (PET), may be used as the material layer. However, a material layer made of biomaterial or another recyclable material that can be formed into three-dimensional packaging containers is also conceivable.

[0092] In a subsequent second step S20, the method comprises forming the material layer into a packaging container 1 with a hollow base 3 and at least one undercut 3d formed in the hollow base 3. Here, the forming step can comprise at least applying forming air and / or a vacuum in the mold cavity of the molding tool 1000, 1000a in order to form the material layer into the mold cavity 160 of the molding tool 1000, 1000a until the material layer comes into contact with the mold base 130 having the at least one undercut element 134 and an inner wall 142 of the mold insert 140. In particular, the forming step S20 can also comprise pre-stretching the material layer with the aid of a pre-stretcher 232, which pre-stretches the two-dimensional material layer into the mold cavity when the molding tool 1000, 1000a is closed.

[0093] In a subsequent third step S30, the packaging container 1 formed in the mold cavity 160 is demolded by axially moving at least a portion of the mold base 130. For example, the at least a portion of the mold base 130 can be lifted (moved into the mold cavity 160) to demold the packaging container 1.

[0094] In a further optional step S40, the molded packaging container 1 can be ejected from the molding tool 1000, 1000a. For this purpose, with the molding tool 1000, 1000a open, at least a portion of the mold base 130 is further raised; thereby, the molded packaging container 1 can be ejected from the mold cavity 160.

[0095] Depending on the design of the molding tool 1000, 1000a, the steps of molding S20 and demolding S30 may comprise the following substeps.

[0096] If the molding tool is configured as described above in connection with Figures 3a to 3e, the molding step S20 can comprise the following substeps: axially displacing the central base element 132 and the at least one undercut element 134 in the direction of the mold cavity 160 in order to turn over the material layer lying in the mold base 130 and to form a container web 3b with at least one undercut 3c in the region of the annular base element. The molding step can further comprise radially displacing the at least one undercut element 134 outward (toward the inner wall of the mold insert 140); as a result, the web inner wall can be displaced toward the web outer wall and thus the width of the container web 3b can be determined; alternatively, the web inner wall can be displaced against the web outer wall until the web inner wall touches the web outer wall.The demolding step may further comprise the following substeps: radially displacing the at least one undercut element inwardly into a starting position in order to demold the container web with the undercut; and further axially displacing the central base element 132 in the direction of the mold cavity 160 in order to completely demold the packaging container 1.

[0097] If, however, the molding tool is designed as described in connection with Figures 2a and 2b, the molding step may comprise molding the material layer into the permanently formed annular gap 138 in order to form a container web 3b with at least one undercut.

[0098] In this case, the demolding step may comprise axially displacing the central base element 132 toward the mold cavity 160 to completely demold the container 1.

[0099] The molding tool and molding process described here enables the production of packaging containers with flat side walls and the possibility of forming a stacking support directly in the hollow base, thus eliminating the disadvantages of conventional packaging containers mentioned above.

Claims

PATENT CLAIMS 1. Molding tool (1000, 1000a), in particular a thermoforming tool (1000, 1000a), comprising a mold base (130, 130a) and a mold insert (140), wherein the mold base (130, 130a) and the mold insert (140) define a mold cavity (160) which is designed to form a packaging container (1) with a hollow base (3), and wherein the molding tool (1000, 1000a) has at least one undercut element (134) for forming at least one undercut (3c) in the hollow base (3).

2. Molding tool (1000, 1000a) according to claim 1, wherein the at least one undercut (3c) formed by the at least one undercut element (134) in the hollow base (3) forms a stack support (3d).

3. Molding tool (1000, 1000a) according to claim 1 or 2, wherein the mold insert (140) surrounds the mold base (130, 130a) in the circumferential direction, wherein the at least one undercut element (134) is arranged radially spaced from the mold insert (140) in the molding tool (1000, 1000a).

4. Molding tool (1000, 1000a) according to one of claims 1 to 3, wherein the at least one undercut element (134) consists of one or more elements which extend / extend in the circumferential direction of the mold base (130, 130a) and are designed to form one or more undercuts (3c) in the circumferential direction of the hollow base (3).

5. Molding tool (1000, 1000a) according to one of claims 1 to 4, wherein the at least one undercut element (134) has a side wall facing the mold insert (140) which is inclined outwards towards the mold insert (140).

6. Molding tool (1000, 1000a) according to one of claims 1 to 5, wherein the at least one undercut element (134) is arranged axially movable in the molding tool (1000, 1000a), wherein for forming the at least one undercut (3c) the at least one undercut element (134) is moved into the mold cavity (160).

7. Molding tool (1000, 1000a) according to claim 6, wherein the at least one undercut element (134) is further arranged radially movable in the molding tool (1000, 1000a), wherein to form the at least one undercut (3c) the at least one undercut element (134) is moved radially outward.

8. Molding tool (1000, 1000a) according to one of claims 1 to 5, wherein the at least one undercut element (134) is arranged stationary in the molding tool (1000, 100a) and projects axially into the mold cavity (160).

9. Molding tool (1000, 1000a) according to one of claims 1 to 8, wherein the mold base (130, 130a) has a central base element (132) and an annular base element (136) surrounding the central base element (132), wherein the at least one undercut element (134) is arranged between the central base element (132) and the annular base element (136).

10. Molding tool (1000, 1000a) according to claim 9, wherein the central base element (132) and the at least one undercut element (134) are arranged to be axially displaceable with respect to the annular base element (136), wherein the central base element (132) and the at least one undercut element (134) are designed to be moved into the mold cavity (160) of the mold insert (140) during a molding process in order to temporarily create an annular gap (138) with at least one undercut (134b).

11. Molding tool (1000, 1000a) according to claim 9 or claim 10, wherein the at least one undercut element (134) is arranged to be radially movable with respect to the central base element (132) in order to produce an annular gap (138) of the desired width during the molding process.

12. Molding tool (1000, 1000) according to one of claims 9 to 11, wherein the at least one undercut element (134) is mounted on the central base element (132).

13. Molding tool (1000, 1000a) according to claim 9, wherein the at least one undercut element (134) is arranged stationary on the annular base element (136) and is further designed to permanently create an annular gap (138) with at least one undercut (134b).

14. Molding tool (1000, 1000a) according to claim 13, wherein the central base element (132) is arranged to be axially displaceable with respect to the annular base element (136).

15. Molding tool (1000, 1000a) according to one of claims 9 to 14, wherein the annular base element (136) forms a structural unit with the mold insert (160).

16. Molding tool (1000, 1000a) according to one of claims 10 to 15, further comprising an actuating device which is designed to actuate the at least one undercut element (134) and / or the centric base element (132) during the molding process and / or during a demolding process.

17. Molding tool (1000, 1000a) according to one of claims 1 to 16, wherein the mold insert (140) has a flat inner wall (142).

18. Molding tool (1000, 1000a) according to one of claims 1 to 16, wherein the mold insert (140) and the mold base (130, 130a) are part of a lower tool part (100), and wherein the molding tool (1000, 1000a) further comprises an upper tool part (200) cooperating with the lower tool part (100).

19. Forming tool (1000, 1000a), in particular a thermoforming tool, which is designed to produce a packaging container (1) with a side wall (2) and with a hollow base (3), wherein the hollow base (3) has at least one undercut (30) and the side wall has a flat outer surface.

20. Use of the molding tool (1000, 1000a) according to one of claims 1 to 19 for producing a packaging container (1) with a hollow base (3) and at least one undercut (3c) formed in the hollow base (3) from a two-dimensional material layer.

21. Molding machine, in particular thermoforming machine, comprising the molding tool (1000, 1000a) according to one of claims 1 to 19.

22. A method for producing a packaging container (1) from a two-dimensional material layer, wherein the method is carried out with the aid of a molding tool (1000, 1000a) which is designed to form a packaging container (1) with a hollow base (3) and at least one undercut (3c) formed in the hollow base (3), and has a mold base (130, 130a) with at least one undercut element (134) and a mold insert (140) which define a mold cavity (160), the method comprising the following steps: Feeding a layer of material to the forming tool (1000, 1000a); Forming the material layer into a packaging container (1) with a hollow base (3) and at least one undercut formed in the hollow base (3), by forming the material layer into the mold cavity (160) of the molding tool (1000, 1000a) at least by applying molding air and / or a vacuum until the material layer comes into contact with the mold base (130, 30a) with the at least one undercut element (134) and an inner wall (142) of the mold insert (140); and Demoulding the packaging container (1) formed in the mould cavity (160) by axially moving at least a part of the mould base (130, 130a).

23. The method according to claim 22, wherein the at least one undercut element (134) is arranged between a central base element (132) and an annular base element (136) surrounding the central base element (132), the forming step comprising: axially displacing the central base element (132) and the at least one undercut element (134) in the direction of the mold cavity (160) in order to turn over the material layer lying on the mold base (130, 130a) and to form a container web (3b) with at least one undercut (3c) in the region of the annular base element (136).

24. The method of claim 23, wherein the forming step further comprises: radially displacing the at least one undercut element (134) outwardly to press the web inner wall against the web outer wall of the container web (3b) formed in the annular bottom element (136).

25. The method according to claim 23 or claim 24, wherein the demolding step further comprises: radially displacing the at least one undercut element (134) inwardly into a starting position in order to demold the container web (3b) with the at least one undercut (3c), and further axially displacing the central base element (132) in the direction of the mold cavity (160) in order to completely demold the container (1).

26. The method according to claim 22, wherein the at least one undercut element (134) is arranged between a central base element (132) and an annular base element (136) surrounding the central base element (132), wherein the at least one undercut element (134) is arranged in a fixed position on the annular base element (136) and forms an annular gap (138) therewith, wherein the forming step comprises: forming the material layer into the annular gap (138) in order to form a container web (3b) with at least one undercut (3c).

27. The method according to claim 26, wherein the demolding step comprises axially displacing the central base element (132) in the direction of the mold cavity (160) in order to completely demold the packaging container (1).

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