Packaging container having a hollow bottom and an undercut formed in the hollow bottom

Abstract

The invention relates to a packaging container (1) which has a side wall (20) and a hollow bottom (10). The hollow bottom (10) has an undercut (30) which forms a stacking support (32). The invention further relates to a thermoforming tool designed to create the packaging container (1) by forming a layer of thermoplastic material. The invention further relates to the use of the thermoforming tool to produce the packaging container (1).

Description

[0001] Packaging container with hollow base and undercut in the hollow base

[0002] TECHNICAL FIELD

[0003] The invention relates to a packaging container and a thermoforming tool for producing a packaging container.

[0004] STATE OF THE ART

[0005] Plastic packaging containers for holding goods are known from the prior art. Depending on their application, such packaging containers can be designed in the form of cups, bowls, or capsules.

[0006] What all packaging containers have in common is that they have a base and a side wall running around a container axis, which together form a hollow space (container interior) for receiving the goods. The hollow space is accessible via a container opening arranged axially opposite the hollow base. The container opening is delimited by a container rim surrounding the container opening. The container rim can, for example, be designed as a sealing rim. A sealing film (for example a metal foil or plastic film) can be attached (for example welded) to it in order to seal the goods received in the container interior from the environment. Additionally or alternatively, the packaging container can have a lid that releasably closes the container at the container opening. A packaging container with a releasable closing lid is known, for example, from WO 2018 / 072892 A1.

[0007] In practice, packaging containers are produced in large quantities, stacked, and then delivered to the customer. To enable reliable separation of the stacked packaging containers, the containers have at least one stacking shoulder (stacking edge) in the circumferential direction of the container in the area of ​​the side wall. The stacking shoulder serves as a support for the container to be picked up (stacked) and is designed and arranged such that the stacked containers are slightly spaced from one another in the base area and / or side wall area. This ensures that the stacked containers do not become wedged and can be easily separated.

[0008] For secure stacking, the packaging containers are provided with at least one stacking shoulder (stacking support). For example, the formation of a stacking shoulder running in the circumferential direction of the container on a predetermined section of the container side wall is known. Containers in which the stacking shoulder is formed near the container edge, i.e. in the axially upper section of the side wall, are referred to as head stackers. Containers in which the stacking shoulder is formed near the container bottom, i.e. in the axially lower section of the side wall, are referred to as bottom stackers. An example of a bottom stacker is known from DE 20 2011 100 097 U1. An example of a head stacker can be found in WO 2018 / 072892 A1.

[0009] The formation of stacking shoulders or stacking supports in the container side wall inevitably leads to containers with stepped side walls. These are impractical and make it difficult to attach information about the product contained in the container or regarding the container's recycling.

[0010] Several techniques are known from the prior art for applying product information to a packaging container. For example, the desired product information can be printed on a thin layer of cardboard or another material (plastic film); the printed material is then cut to fit the container's dimensions, producing a so-called label, which is subsequently applied (e.g., glued) to the outer surface of the side wall. The advantage of this technique is that it achieves excellent print quality; the disadvantage, however, is that it is expensive and time-consuming due to the many work steps (pre-printing, cutting, and application). If a label is used as a carrier for the product information, only the outer surface of the container side wall that is flat and has no steps can be used.

[0011] Another technique involves printing the product information directly onto the outer surface, which is significantly cheaper and faster than printing and subsequently attaching printed labels to the packaging container. Conventional color printing technologies can be used for this. However, direct printing technology requires flat, printable outer surfaces. In conventional packaging containers, however, these are often limited to a relatively small central sidewall section, as stacking shoulders and / or other structures, such as reinforcing ribs, are formed in the wall sections near the container base and / or container edge.

[0012] It is therefore an object of the present invention to provide a packaging container that meets the industry's requirements in terms of stability, stackability, and container separation. In addition, the packaging container should have the largest possible directly printable outer surface, so that the aforementioned advantages of direct printing can be fully exploited.

[0013] BRIEF SUMMARY

[0014] To achieve at least the above-mentioned object, according to a first aspect, a packaging container is provided, wherein the packaging container has a side wall and a hollow base, and wherein the hollow base has an undercut forming a stacking support.

[0015] By forming the stacking support / stacking shoulder (directly) in the hollow base, there is no need for stacking supports or stacking shoulders on the side wall. This means that the side wall of the container can be designed to be flat (i.e. without steps or protrusions and / or indentations) from the container edge to the container base. The outer surface(s) of the side wall can thus be printed directly; in particular, the entire side wall (i.e. from the container edge to the base) can be fully printed. This is particularly advantageous for small packaging containers with small printable outer surfaces. At the same time, the provision of the stacking support (stacking shoulder) in the hollow base ensures that the packaging containers can be safely stacked and separated again. The design of the base as a hollow base also ensures the necessary stability of the packaging container.

[0016] The packaging container can, in particular, be rotationally symmetrical; the axis of rotation of the packaging container (hereinafter referred to as the container axis) can run through the center of the hollow base; furthermore, the side wall can be designed such that it surrounds the container axis at a predetermined radial distance. According to one variant, the side wall can be tapered towards the hollow base; in this case, the radial distance of the side wall from the container axis in the container edge region can be greater than the radial distance of the side wall from the container axis in the container base region. In particular, the side wall angle can be an angle in the range from 1° to 40°, preferably in the range from 1° to 15°. Here, the term "side wall angle" refers to the angle of inclination that the side wall has with respect to the container axis.In other words, side wall angle means the angle formed by the container axis and the side wall line in a sectional view parallel to the container axis.

[0017] The side wall surrounding the container axis, together with the hollow base, forms a cavity (container interior). The container interior can be designed to accommodate a product (e.g., dairy products, beverages, or ready meals). The cavity can be accessible via a container opening arranged axially opposite the hollow base. The container opening can be radially delimited by a container rim surrounding the container axis. The container rim can be designed as a sealing rim.

[0018] Depending on requirements, the packaging article can be designed as a cup, bowl or capsule. A hollow base refers to a base that has an inner base region and a web region 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. This means that 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 protruding web region. The web region thus acts 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.

[0019] The web region surrounding the inner base region can be continuous or discontinuous in the circumferential direction of the container. Furthermore, according to the present invention, the undercut can be formed at the transition between the web region and the inner base region. In particular, the undercut at the transition between the web region and the inner base region can be continuous or sectioned in the circumferential direction. The continuous or sectioned formation of the undercut at the transition between the web region and the axially recessed inner base region creates a stable stacking support (stacking shoulder) directly in the hollow base. Compared to conventional packaging containers, the design of the container is thus further simplified; in particular, the container can have a flat (tapered) side wall that is easy and fully printable.

[0020] In particular, the web region can be double-walled, with a web inner wall facing the base inner region and a web outer wall facing away from the base inner region. According to one variant, the web inner wall can be arranged radially spaced from the web outer wall. According to another variant, the web inner wall can be in contact with the web outer wall or can be crimped thereto, as described in EP 1 163 996 B1. In both variants, the undercut is preferably formed on the web inner wall. In particular, the undercut can be formed continuously in the circumferential direction or in sections on the web inner wall. Preferably, the undercut can be formed by the web inner wall or sections of the web inner wall being inclined away from the base inner region; in particular, the web inner wall can be inclined by an angle greater than 90° with respect to the (essentially horizontally oriented) base inner region.This inclined design of the inner web wall creates a (protruding) stacking shoulder at the transition between the inner web wall and the inner base area, which acts as a stacking support for a packaging container of the same shape.

[0021] The outer web wall can be formed as an extension of the container side wall. In particular, the outer web wall can be designed and / or inclined such that it merges essentially seamlessly into the side wall of the packaging container. In particular, the outer web wall can have the same inclination as the tapered side wall. In this way, a uniform printable outer surface can be created that extends essentially from the container edge to the web support of the web region.

[0022] In a particularly simple embodiment, the inner and outer web walls can be squashed together and have the same inclination as the tapered side wall. In an alternative embodiment, the inner and outer web walls can be arranged radially spaced from one another and inclined to different degrees. The inclination of the outer web wall can be adapted to the inclination of the side wall, creating a uniform printable outer surface. The inclination of the inner web wall, on the other hand, can be selected such that a pronounced undercut and, with it, a clearly pronounced stacking shoulder is created at the transition between the web area and the inner base area.

[0023] The packaging container can be made of metal, plastic, cardboard, or another material, in particular a recyclable or degradable material. According to one variant, the packaging container can be made of a thermoplastic material. According to a further aspect of the invention, a thermoforming tool is provided that is designed to produce the packaging container described above by forming a layer of thermoplastic material. For example, PET, polypropylene, or another thermoplastic material can be used as the thermoplastic material.

[0024] In particular, the thermoforming tool can be a multiple thermoforming tool with a plurality of mold cavities, which is designed to produce a plurality of the packaging containers described above simultaneously in one molding cycle.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further details and advantages of the invention are explained with reference to the following drawings. They show:

[0027] Figures 1a / 1b show three-dimensional views of a packaging container according to the present invention;

[0028] Figures 2a / 2b show further views of the packaging container according to Figures 1a / 1b;

[0029] Figures 3a / 3b show three-dimensional views of another packaging container according to the present invention;

[0030] Figures 4a / 4b show further views of the packaging container according to Figures 3a / 3b;

[0031] Figures 5a-5d are three-dimensional views of another packaging container according to the present invention; and

[0032] Figures 6a / 6b Views of stacked packaging containers according to Figures 5a-

[0033] 5d.

[0034] DETAILED DESCRIPTION

[0035] Examples of packaging containers according to the invention are described in more detail below. It should be understood that these examples serve to better understand the invention and that the invention is not intended to be limited to these specific examples. Figures 1a and 1b show three-dimensional views of a packaging container 1 according to the invention.

[0036] The packaging container 1 comprises a base 10 and a side wall 20, which together form a container interior 18. The container interior 18 is accessible via a container opening 16, which is arranged opposite the base 10. The container opening is delimited by a container rim 40, which surrounds the container opening 16. The container rim 40 is arranged at an axial end of the side wall 20 facing away from the base 10.

[0037] The packaging container 1 is rotationally symmetrical, with the container's axis of rotation (container axis) running through the center of the base 10 (see Figure 2a). The side wall 20 surrounds the container axis at a predetermined radial distance. This radial distance is greatest at the container opening 16 (i.e., at the container edge 40) and decreases continuously (e.g., linearly) toward the base 10. The container side wall 20 thus has a shape that tapers conically toward the base, with the side wall angle α of the side wall tapering conically toward the base having an angle in the range of 1° to 40°, preferably in the range of 1° to 15°. Side wall angle α refers to the angle of inclination of the side wall 20 with respect to the axis of rotation (see also the sectional view in Figure 2a).

[0038] The base 10 of the packaging container 1 is designed as a hollow base 10. The hollow base 10 has an inner base region 12 and a web region (or web for short) 14 surrounding the inner base region 12. The inner base region 12 is axially set back with respect to the web 14 (i.e., axially displaced in the direction of the container interior 18). This creates the structure typical of a hollow base, in which the container 1 rests on an underlying horizontal support surface (e.g., a tabletop) solely via its axially projecting web 14, while a hollow space is created in the region of the set-back inner base region 12. The web 14 of the packaging container 1 is described further in connection with Figure 2b. The web 14 is double-walled, with a web inner wall 14b and a web outer wall 14a located radially further outward.Furthermore, the web 14 has a (horizontal) web support 14c, with which the packaging container 1 can rest on a horizontal support surface. The web outer wall 14a and the web inner wall 14b are connected to each other via the wall of the web support 14c. Furthermore, the web 14 is continuous in the circumferential direction (see Figures 1a and 1b). This creates a stable container support. In an alternative embodiment, however, the web 14 can also have interruptions in the circumferential direction.

[0039] The outer web wall 14a transitions seamlessly into the side wall 20 of the packaging container 1. Furthermore, the outer web wall 14a is inclined. The inclination of the outer web wall 14a essentially corresponds to the inclination a of the side wall 20. The continuous transition and the same inclination create a uniform, printable outer container surface 24 in the axial direction of the container 1, which extends essentially from the container edge 40 to the web support 14c.

[0040] The web inner wall 14b forms the transition between the web 14 and the floor inner region 12. It connects the wall of the web support 14c with the wall of the axially inwardly recessed floor inner region 12. The web inner wall 14b is inclined with respect to the horizontal wall of the floor inner region 12 and the web support 14c, in such a way that the inclination of the web inner wall 14b creates an undercut 30 at the transition between the web 14 and the floor inner region 12. As can be seen from the sectional view in Figure 2b, the undercut 30 can be achieved by the web inner wall 14b being inclined more outwards (i.e. inclined away from the floor inner region 12) than the web outer wall 12a, starting from the horizontal web support 14c.In other words, the angle of inclination ß that the inclined web inner wall 14b forms with the container axis is greater than the angle of inclination α that the web outer wall 14a forms with the container axis (see Figure 2b). As an alternative to the design shown in Figure 2b, the angle of inclination ß that the inclined web inner wall 14b forms with the container axis can also be smaller than the angle of inclination α that the web outer wall 14a forms with the container axis. In both design variants, the web inner wall 14b extends obliquely outwards from the web support 14c, whereby in the area where the web inner wall 14b merges into the horizontal wall of the base inner region 12, a stacking support 32 (also called a stacking shoulder 32) is formed, which can be used for securely stacking the packaging containers 1.Similar to the web 14, the undercut described here can also be continuous or intermittent in the circumferential direction of the packaging container.

[0041] The stacking of the packaging containers 1 is further illustrated in Figure 2b. The nested containers 1 rest with their respective web supports 14c against the stacking shoulder 32 of the outer packaging container 1 formed in the hollow base 10.

[0042] A further packaging container 1a according to the present invention is described in conjunction with Figures 3a and 3b. Figures 3a / 3b show three-dimensional representations of the packaging container 1a. This again has a base in the form of a hollow base 10 with an inner base region 12 and a web region 14a (web 14a for short) surrounding the inner base region, a side wall 20, and a container rim 40. The container rim 40 can optionally be designed as a sealing rim. The side wall 20 and the hollow base 10 form a container interior 18, which is accessible via a container opening 16 arranged opposite the base 10. The container opening is delimited by the container rim 40. The bottom inner region 12 is formed axially inwardly (i.e. set back in the direction of the container interior 18) with respect to the circumferential web region 14a, as described above in connection with the packaging container 1 of Figures 1a / 1b and 2a / 2b.

[0043] The packaging container 1a differs from the packaging container 1 according to Figures 1a / 1b and 2a / 2b primarily in the design of the web 14 and is described further in connection with Figure 4a. The web 14 of the packaging container 1a is double-walled, with an outer web wall 14a and an inner web wall 14b. In contrast to the packaging container 1, the outer web wall 14a and the inner web wall 14b are formed so as to be adjacent to one another or squeezed together. Thus, the web 14 of the packaging container 1a has no hollow space, which may be desirable depending on the product contained in the container 1a. Furthermore, the web 14 of the packaging container 1a is formed substantially thinner in the radial direction than the web 14 of the container 1.

[0044] Regardless of this different arrangement, the web outer wall 14a and the web inner wall 14b are again inclined (outwardly). The web outer wall is arranged such that it transitions essentially seamlessly into the side wall 20 of the packaging container 1. Similar to the packaging container 1 of Figures 1a / 1b, the inclination of the web outer wall 14a essentially corresponds to the inclination a of the side wall 20. Due to the continuous transition and the same inclination, a uniform, printable container outer surface 24 is again created in the axial direction of the container 1, which extends essentially from the container edge 40 to the web support 14c (see Figure 4a).

[0045] The web inner wall 14b forms the transition between the web 14 and the base inner region 12. It connects the web support 14c to the wall of the axially inwardly recessed base inner region 12. The web inner wall 14b is inclined with respect to the horizontal wall of the base inner region 12 and the web support 14c. It has essentially the same inclination as the web outer wall 14a. The inclination creates an undercut 30 directly at the transition between the web 14 and the base inner region 12. Furthermore, in the area where the web inner wall 14b merges into the horizontal wall of the base inner region 12, a stacking support 32 (stacking shoulder 32) is created, which can be used for securely stacking the packaging containers 1.

[0046] The stacking of the packaging containers 1a is further illustrated in Figure 4b. The nested containers 1 rest with their respective web supports 14c on the stacking shoulder 32 of the outer packaging container 1 formed in the hollow base 10. A further packaging container 1b according to the present invention is described in conjunction with Figures 5a to 5d. Figure 5a shows a three-dimensional view of the packaging container 1b. Figure 5b shows a plan view, and Figures 5c and 5d show sectional views along lines AA and BB.

[0047] The packaging container 1b differs from the packaging container 1 only in the design of the undercut 30 at the transition between the web 14 and the inner base area 12 of the hollow base 10. Only the differences are described below. All other features of the packaging container 1b correspond to the features of the packaging container 1 shown in Figures 1a / 1b and 2a / 2b and will not be described further below. Reference is made to the description of these features in connection with the packaging container 1.

[0048] In contrast to the packaging container 1, the packaging container 1c differs in that the undercut 30 in the hollow base 10 is not continuous in the circumferential direction, but is formed in sections. This is achieved in terms of construction by the inclination of the web inner wall 14b varying in sections in the circumferential direction of the container 1b. As can be seen from Figures 5b, 5c and 5d, the web inner wall 14b has first sections 14bl in the circumferential direction (see Figure 5c), which are inclined outwards starting from the web support 14c and thus create an undercut (as described above in connection with the container 1) and second sections 14b2, which are essentially perpendicular to the web support 14c (see Figure 5d). Thus, no undercut is formed in the second sections 14b2.In this embodiment, too, a stacking shoulder 32 is formed at the transition of the respective first web inner wall sections 14bl to the horizontal wall of the bottom inner region 12. This is interrupted in the circumferential direction of the container 1b by the second web inner wall sections 14b2.

[0049] The stacking of the packaging containers 1b is further illustrated in Figures 6a and 6b. The nested containers 1b rest with their respective web supports 14c against the stacking shoulder 32 of the outer packaging container 1 formed on the first web inner wall sections 14bl (see Figure 6a). No stacking shoulder 32 is formed in the area of ​​the second web inner wall sections 14b2, so that the stacked containers 1b do not touch each other there (see Figure 6b).

[0050] The containers 1, 1a, and 1b described here can be made of plastic or another (recyclable or biodegradable) material. They can be manufactured, for example, using injection molding or a thermoforming process. The use of a thermoforming process is particularly advantageous, as it allows the containers 1, 1a, and 1b to be produced in large quantities, with high quality, and cost-effectively.

[0051] All of the packaging containers described here have in common that the stacking shoulder or stacking support is formed directly in the hollow base. This eliminates the need for a stacking support or stacking shoulder in the area of ​​the side wall. This allows the side wall to be flat and without any steps. The containers according to the invention are therefore particularly well suited for direct printing with product information on the outer surface of the container.

Claims

PATENT CLAIMS 1. Packaging container (1, 1a, 1b), wherein the container (1, 1a, 1b) has a side wall (20) and a hollow base (10), wherein the hollow base (10) has an undercut (30) forming a stacking support (32).

2. Packaging container (1, 1a, 1b) according to claim 1, wherein the hollow base (10) has an inner base region (12) and a web region (14) surrounding the inner base region (12), wherein the undercut (30) is formed at the transition between the web region (14) and the inner base region (12).

3. Packaging container (1, 1a, 1b) according to claim 2, wherein the undercut (30) is formed in sections or continuously in the circumferential direction of the container (1, 1a, 1b).

4. Packaging container (1, 1a, 1b) according to claim 2 or claim 3, wherein the web region (14) is double-walled with a web inner wall (14b) facing the base inner region (12) and a web outer wall (14a) facing away from the base inner region (12), wherein the undercut (30) is formed on the web inner wall (14b).

5. Packaging container (1, 1a, 1b) according to claim 4, wherein the undercut (30) is formed in that the web inner wall (14b) or sections of the web inner wall (14b) is / are inclined away from the bottom inner region.

6. Packaging container (1, 1a, 1b) according to claim 4 or 5, wherein the web inner wall (14b) and the web outer wall (14a) are arranged at a distance from one another or touch one another.

7. Packaging container (1, 1a, 1b) according to one of claims 4 to 6, wherein the web outer wall (14a) and the side wall (20) of the container (1, 1a, 1b) form a printable outer surface (24) which is continuously flat in the axial direction.

8. Packaging container (1, 1a, 1b) according to claim 7, wherein the outer surface (24) is tapered in the axial direction.

9. Packaging container (1, 1a, 1b) according to one of claims 1 to 8, wherein the container (1, 1a, 1b) is produced by thermoforming a thermoplastic material layer.

10. Thermoforming tool designed to produce a packaging container (1, 1a, 1b) according to one of claims 1 to 9 by forming a material layer made of thermoplastic material.

11. Use of the thermoforming tool according to claim 10 for producing a packaging container (1, 1a, 1b) according to one of claims 1 to 9.

Images