Container for receiving food, method for producing such a container, food unit comprising such a container, and method for producing such a food unit

Abstract

The invention relates to a container for receiving food, having a container body (1) consisting of ceramic, porcelain, glass or metal and comprising a base (2), one or more lateral walls (3) and a peripheral upper container edge (4). The container is characterized in that a peripheral plastic element (12), the upper face (14) of which is exposed, is secured to the container edge (4) by means of an adhesive (11).

Description

[0001] Container for holding food, method for producing such a container, food unit comprising such a container and method for producing such a food unit

[0002] The invention relates to a container for holding foodstuffs, with a container body made of ceramic, porcelain, glass or metal, comprising a base, one or more side walls and a circumferential upper container edge.

[0003] In many areas of daily life, various types of food are placed in containers and then sealed with a film seal to protect the food. Such film-sealed containers or food units can be found, for example, in supermarkets, but also in the catering industry. Plastic containers are regularly used to create such a food unit, allowing a sealing film, also made of plastic, to be bonded or welded to the plastic container in a sealing process. This allows for a sufficiently tight bond, yet the sealing film can be torn off if necessary to open the container.Although such plastic containers can now be recycled, the container itself, along with the recyclable sealing film, is initially disposed of as waste when such a food unit is used. The use of reusable containers made of ceramic, porcelain, glass, or metal is not possible, as the plastic sealing film cannot be bonded to the ceramic, porcelain, glass, or metal body.

[0004] The invention is based on the problem of providing a container made of ceramic, porcelain, glass, or metal that is suitable for use in a film seal. To solve this problem, the invention provides for a container of the type mentioned above to have a circumferential plastic element, the upper side of which is exposed, attached to the container edge by means of an adhesive.

[0005] The ceramic, porcelain, glass, or metal container according to the invention has a container body made of this material, with a base and one or more side walls. If the container is round or oval, only one circumferential, circular, or oval side wall is provided; in the case of a polygonal, for example rectangular, container, four side walls are provided accordingly. According to the invention, a plastic element running around the entire edge, the upper side of which is exposed, is attached to this container edge by means of a suitable adhesive. In a first embodiment, the container edge can be flat, i.e., unprofiled, so that the plastic element is placed on the flat edge surface. Alternatively, according to the invention, one or more side walls can be profiled in a special way at their free edge. According to the invention, the container edge can be provided with an upwardly open, circumferential groove, i.e.,that this round, oval or polygonal, circumferential groove is formed at the upper end of the container. According to the invention, a plastic element is held on the container rim or in this groove by means of a suitable adhesive and runs along the entire container rim or the entire groove. Such a one-piece plastic element, which can also be referred to as a plastic frame, is placed or inserted on the container rim or in the groove and is firmly connected to the container body via the adhesive. The plastic element serves as an interface component in order to attach a sealing film to the container, once it has been provided with a food product, in a sealing process and to seal the container and thus the food product airtight. This is because the plastic element offers a corresponding material interface at which the sealing process, which takes place at an elevated temperature, for example of approx.150 - 180 °C, enabling a material-to-material bond between the plastic sealing film and the plastic element. To achieve this, the top side of the plastic element is exposed or, if provided, the plastic element protrudes slightly from the groove, i.e., it protrudes slightly with a circumferential top side, which is preferably flat, so that any sealing film to be applied comes into contact exclusively with the protruding top side of the plastic element, where a material-to-material seal can be achieved.

[0006] When using such a food unit, consisting of the container with the food inside and the sealed film, the sealing film can be easily torn off to open the container, breaking the bond between the sealing film and the plastic element. After the food has been consumed, the ceramic, porcelain, glass, or metal container, to which the plastic element is ultimately inseparably attached via the adhesive as described above, can be easily reused. It simply needs to be cleaned accordingly, after which it can be subjected to another sealing and sealing process.The use of such a ceramic, porcelain, glass or metal container in the production of such food units is therefore particularly sustainable due to the almost unlimited reusability of the container, just as such a ceramic, porcelain, glass or metal container is visually appealing and of significantly higher quality, which is particularly desirable in the catering sector.

[0007] The plastic element preferably has a flat upper surface, i.e., it is flat at the interface where the sealing film is welded. This ensures a sufficiently large contact area between the sealing film and the plastic element, which translates into a sufficiently large, material-to-material bond.

[0008] The plastic element is expediently rectangular in cross-section, and is preferably wider than it is high. It can, for example, have a width of 3 - 4 mm, with a height of the rectangular cross-section of, for example, 1.5 - 2.5 mm, although these values ​​are only examples and not restrictive. As already described, the plastic element protrudes slightly from the groove, i.e. projects beyond the groove edges of the container body that border the groove on both sides. This projection does not have to be too great, but it should be at least 1 mm, preferably at least 2 mm, i.e. the plastic element consequently protrudes from the groove by at least 1 mm or at least 2 mm.

[0009] According to a further development, several protruding spacers can be provided on the plastic element on the side facing the container edge or the groove. These spacers, preferably in the form of small protruding knobs, rest on the flat container edge or, if provided, on the groove base in the assembled position, thus creating a defined plane in which the plastic element runs. Furthermore, the spacers also serve to bridge any tolerances in the container body, which, being made of ceramic or porcelain, is fired. A certain amount of shrinkage always occurs during firing, which can potentially lead to local irregularities, particularly in the edge area and thus in the groove area.The top surface of the plastic element must be level to provide a flat support surface for the sealing device's welding plate, which presses the sealing film onto the plastic element and heat-welds it. The spacers serve to accommodate or bridge these tolerances. At the point where the container body has the smallest tolerance, the corresponding spacer rests on the container rim or the groove base. At positions with greater deviation, however, the plastic element floats. This ultimately results in the plastic element or its top surface running exactly in one plane, allowing for the best possible welding of the sealing film.

[0010] In a rectangular plastic element, the spacers are provided at least in the area of ​​the corners, while in a circular plastic element, the spacers are distributed equidistantly along the length. The plastic element itself is preferably embedded in the adhesive in a floating manner, at least in sections, regardless of whether spacers are provided or not. This means that the plastic element can, but does not have to, be in contact with the groove base locally; instead, it is floatingly received in the adhesive, which ensures the flatness of the top side described above.

[0011] The groove, if provided, is preferably wider than the plastic element, preferably by at least 1 mm, in particular by at least 2 mm, which facilitates the insertion of the plastic element.

[0012] The plastic element itself can be made of various plastics suitable for a film sealing process, i.e., plastics that can form a correspondingly bonded bond with the sealing film used. A plastic element made of polypropylene (PP) or polyethylene terephthalate (PET) is preferably used. The plastic element can consist of a single plastic material, but it would also be conceivable to manufacture the plastic element from, for example, two different material layers: a first material layer facing the groove base, which, for example, allows improved adhesion to the adhesive, and a second material layer forming the top side, which allows improved adhesion to the sealing film.

[0013] According to a particularly advantageous development of the invention, the adhesive is elastic when cured. The plastic element is therefore firmly fixed in the groove by an elastic adhesive, but is slightly movable within the limits of the elasticity of the adhesive. This mobility enables further tolerance compensation because, when the sealing film is pressed onto the plastic element via the welding plate during welding, the plastic element can also give slightly locally if necessary, ensuring optimal contact of the plastic film over the entire surface of the upper side. This means that any unevenness in the groove surface or groove base can be optimally compensated for, particularly when the plastic element is supported towards the groove base by a somewhat thicker layer of adhesive, i.e. is bonded in a correspondingly floating manner.

[0014] A silicone-based compound is particularly preferred as the adhesive, which in particular exhibits the elastic properties described above when cured. The compound is preferably a 1-component silicone, i.e. a silicone that cures without additional hardeners or crosslinkers. An example of such a silicone is the TB 90N silicone casting compound from Tomabond GmbH. This silicone is a highly transparent, tensile-strength casting compound that is particularly suitable for use in the food industry and is characterized by good adhesion to material surfaces, especially ceramic or porcelain, which ensures a correspondingly strong adhesive bond. The silicone also displays good chemical and aging resistance, which is particularly advantageous for permanent reuse, which always requires intensive cleaning.The silicone hardens through a chemical reaction with humidity.

[0015] In addition to the container itself, the invention relates to a method for producing a container of the type described above, comprising the following steps:

[0016] - Providing a container body comprising a base, one or more side walls and a continuous upper container edge,

[0017] - Applying the adhesive to the container rim,

[0018] - Inserting the plastic element into the adhesive,

[0019] - Curing of the adhesive.

[0020] In a further development of the method, the following steps are provided: providing a container body (1) comprising a base (2), one or more side walls (3) and a surrounding upper container edge (4), wherein an upwardly open, surrounding groove (6) is provided on the container edge (4), introducing the adhesive (11) into the groove (6), inserting the plastic element (12) into the groove (6), curing the adhesive (11).

[0021] The starting point is the container body made of ceramic, porcelain, glass or metal with either a flat container rim or with a groove formed on it and running around the upper container rim. The adhesive, which is preferably a silicone-based compound, in particular a 1-component silicone, is applied to the flat rim or into this groove, if necessary after prior cleaning with a suitable cleaning agent. The adhesive can be applied manually or mechanically. The frame-like plastic element is then pressed into the still fluid adhesive, i.e., if present, inserted into the groove, whereby this insertion can also be done manually or mechanically. Depending on the amount of adhesive or the fill level of the groove, the plastic element is embedded in the adhesive accordingly, which allows for a sufficiently strong bond.The plastic element is inserted in such a way that, when a groove is formed, it always protrudes from the groove in a defined manner, thus protruding beyond the two groove edges that define the upper container rim. In any case, the top of the plastic element is exposed and forms an interface for the sealing film to be welded on. After the plastic element is inserted, the adhesive cures. Depending on the adhesive used, the curing time can range from a few minutes to a few hours.

[0022] The groove is preferably filled with the adhesive to at least 50% of its volume, in particular to at least 70% of its volume. This ensures sufficient embedding of the inserted plastic element.

[0023] The plastic element itself can be treated with plasma before insertion. This plasma treatment can activate the surface for a better bond to the adhesive, preferably the silicone compound. The plastic element is preferably pressed into the adhesive using a pressure plate, i.e., a surface element that applies defined pressure to the entire upper surface of the plastic element. This pressure plate can be guided manually, but is preferably mechanically, resulting in automated insertion.

[0024] The plastic element used is preferably made of polypropylene, polyethylene terephthalate, or high-density polyethylene, with the plastic element preferably consisting solely of polypropylene, polyethylene terephthalate, or high-density polyethylene. Alternatively, plastic elements made of other plastics can also be used, as long as they form a sufficiently strong welded bond with the plastic sealing film.

[0025] The invention further relates to a food unit comprising a container of the type described above, into which one or more food items are placed, and which is sealed with a sealing film that is tearably attached to the plastic element using a sealing process. Thus, in addition to the container according to the invention, the food unit also comprises one or more food items placed therein, as well as the welded-on sealing film. The food unit is therefore the final unit as it is ultimately delivered to the consumer.

[0026] Finally, the invention also relates to a method for producing a food unit of the type described above, comprising the following steps:

[0027] - Providing a container of the type described above,

[0028] - Applying a sealing film to the plastic element by means of a film sealing device, forming a material-to-material connection between the sealing film and the plastic element.

[0029] Sealing, i.e., the application of the sealing film, can optionally be carried out under nitrogen, with which the volume of the interior of the container of the final food unit is filled. Further advantages and details of the present invention will become apparent from the exemplary embodiments described below and from the drawings. In the drawings:

[0030] Fig. 1 is a sectional view through a container body used for the production of a container according to the invention,

[0031] Fig. 2 is a partial plan view of the container body of Fig. 1,

[0032] Fig. 3 is a sectional view corresponding to Fig. 1 of a container according to the invention with adhesive introduced into the groove of the container body and inserted plastic element,

[0033] Fig. 4 is a partial view corresponding to Fig. 2 of the container from Fig. 3,

[0034] Fig. 5 is a sectional view corresponding to Fig. 3 after introduction of a food into the container and application of a sealing film to form a food unit,

[0035] Fig. 6 is a partial view corresponding to Fig. 4 of the food unit from Fig. 5,

[0036] Fig. 7 a view from below of the plastic element to be inserted into the groove,

[0037] Fig. 8 a side view of the plastic element from Fig. 7

[0038] Fig. 9 is a sectional view through a container body of a second embodiment used for producing a container according to the invention,

[0039] Fig. 10 is a sectional view corresponding to Fig. 9 of a container according to the invention with adhesive applied to the flat container edge and inserted plastic element, Fig. 11 is a partial view as a plan view of the container from Fig. 10,

[0040] Fig. 12 is a sectional view corresponding to Fig. 10 after introduction of a food into the container and application of a sealing film to form a food unit.

[0041] Fig. 1 shows a sectional view of a container body 1, Fig. 2 shows a partial view in a plan view of the container body 1. The container body 1 has a base 2 and a total of four side walls 3, of which only three are shown here due to the sectional view. The side walls 3 form an upper, circumferential container edge 4, which extends horizontally over an edge section 5 projecting to the side. A circumferential groove 6 is formed on the container edge 4 or the edge section 5, which is delimited on both sides by corresponding edge webs 7 and at the bottom by a groove base 8. The groove 6 is open at the top. It runs completely around the rectangular container 1, as also shown in Fig. 2. In the area of ​​the corners 9, the container is rounded, which applies equally to the container edge 4 and thus necessarily also to the course of the groove 6.

[0042] Groove 6, for example, is 1.5–2 mm deep and 6–7 mm wide. The dimensions of the groove are preferably always the same for different container sizes, as it serves to accommodate a plastic element that forms an interface for arm welding a sealing film. This interface should always be of comparable design, regardless of the container size.

[0043] 3 and 4 show the finished container 10, comprising the container body 1 from FIGS. 1 and 2. An adhesive 11, preferably a silicone-based compound, in particular a 1-component silicone, is introduced into the groove 6, wherein during this introduction the groove 6 is approximately 70% filled with the fluid adhesive 11. The introduction of the adhesive 11 can be carried out manually, but is preferably carried out automatically via a suitable dispensing device. A plastic element 12, which is frame-like and whose shape corresponds to the geometry or course of the groove 6, is inserted into the still fluid adhesive 11 and pressed into the adhesive 11 such that the adhesive 11 embeds the plastic element 12 below and on the sides, as shown in FIG. 3 and also in FIG. 4.The plastic element 12 is preferably made of polypropylene or polyethylene terephthalate and has a substantially rectangular cross-section, with a plurality of spacers 13, for example rounded knobs, possibly protruding from the underside and resting on the groove base 8, for example locally at points where there are no or only slight tolerances. This means that these spacers 13, or at least part of them, can be used to compensate for tolerances or to compensate for any unevenness in the groove base 8. This serves to ensure that the top side 14 of the plastic element 12 is absolutely flat. This is because the top side 14 forms the sealing surface of the plastic element 12, to which a sealing film is to be attached using a thermal sealing process.The upper side 14 of the plastic element 12, which has a rectangular cross-section, is already flat, and the tolerance compensation described ensures that the upper side 14 extends in one plane over the entire extent of the plastic element 12. The plastic element 12 is preferably inserted or inserted using a corresponding pressure plate, with which the plastic element 12 is pressed into the adhesive 11 and thus into the groove 6 in a defined manner. This insertion can be done manually or, preferably, automatically.

[0044] As described, the adhesive 11 is preferably a silicone-based compound, i.e. a silicone adhesive. This adhesive preferably cures elastically, i.e. the cured adhesive has intrinsic elasticity. This in turn means that the plastic element 12 is somewhat movable relative to the container 1. This slight mobility offers a further possibility for tolerance compensation, since the plastic element 11 can give slightly due to pressure during application of the sealing film, in which the sealing film is pressed onto the plastic element 11 with a certain pressure. Since the sealing film is pressed on using a suitable heating plate, a uniform pressure is created, which the plastic element 12 can follow. In the areas where it is not resting on the groove base 8 with a spacer 13 and is therefore floatingly embedded in the adhesive 11, it can follow.

[0045] In the assembly position shown in Fig. 3, the plastic element 12 protrudes slightly from the groove 6, thus protruding beyond the edge webs 7, so that the upper surface 14 represents the uppermost level with which the sealing film comes into contact during sealing and to which the sealing film can be attached. For this purpose, the plastic element 12 has appropriate dimensions. It should have a width of approximately 2.5 - 5 mm so that it can be easily inserted into the groove 6. The thickness of the plastic element

[0046] 12 should be at least 2 mm, whereby in the plane of a spacer

[0047] 13, of course, has a somewhat greater thickness. A spacer 13, for example, has a length of 0.75 - 1 mm. A basic thickness of 2 mm in the rectangular cross-sectional area is sufficient to ensure a sufficient projection of, for example, 1 - 1.5 mm due to the quasi-floating embedding in the adhesive 11.

[0048] An example of such a plastic element 12 is shown in Fig. 7 and 8. The shape of the plastic element 12 clearly corresponds to the shape and profile of the groove 6, it is just somewhat narrower. Fig. 7, which shows a view of the underside facing the groove base 8, also shows the spacers 13, which in this case are primarily provided in the corner area, where the container body 1 usually has the smallest tolerances, i.e. the plastic element 12 is supported in the corner area by the spacers 13 towards the groove base 8. In the other areas, the plastic element 12 lies floating in the adhesive 11. The spacers 13 are also clearly visible in the side view shown in Fig. 8.

[0049] The container 10 according to the invention is configured for use in a film sealing process by attaching the plastic element 12. Within this process, a food product 15, which is shown only as an example in Figs. 5 and 6, is introduced into the container 10. The container 10 is then introduced into a film sealing machine, in which a sealing film 16 is thermally welded to the top side 14 of the plastic element 12 via a material-to-material bond. This is achieved by means of a heating plate, with which the sealing film 16 is pressed against the top side 14 of the plastic element 12. At elevated temperatures, for example, a sealing temperature of 170°C, a material bond is formed between the sealing film 16 and the plastic element 14, so that the interior containing the food product 15 is completely hermetically sealed. The interior can be filled with nitrogen during the sealing process.The integral connection between the sealing film 16 and the plastic element 12 is detachable, meaning that, if necessary, when the food 15 is to be consumed, the sealing film 16 can be easily torn off. Figs. 5 and 6 accordingly show the food unit 17, which can be formed by using the container 10 and inserting the food 15 with the sealing film 16 welded on.

[0050] The sealing film 16 is a suitable plastic film that can consist of a single plastic material, but usually consists of several different plastic layers, each only a few micrometers thick. Often, one plastic layer is made of polyethylene (PP), onto which a layer of ethylene-vinyl acetate (EVA) is applied. The layer composite can also contain a further polymer layer, for example, of polyethylene terephthalate (PET). In principle, the mentioned plastic layers and their number are not exhaustive; rather, other plastic layers or materials can also be used, as long as the sealing film forms a strong bond with the plastic element 12.

[0051] Figs. 9 - 12 show a further exemplary embodiment. Here, see Fig. 9, a container body 1 with a flat container rim 4 with a widened, flat edge section 5 is used. The adhesive 11 is applied to this flat container rim 4 or edge section 5 (see Figs. 10 and 11), into which the plastic element 12 is then inserted and embedded. The plastic element 12, preferably also provided with spacers 13, also protrudes slightly from the adhesive 11 here so that its upper side 14 is exposed. After curing, a container body 1 is again produced with a defined interface formed by the plastic element 12 for attaching a sealing film.

[0052] Such a sealing film is shown in Fig. 12. It is welded onto the top side 14 of the plastic element 12, so that the food 15 introduced into the container body 1 is hermetically sealed. Detailed explanations made for the embodiment according to Figs. 1 to 8 also apply equally to the example according to Figs. 9 to 12, unless they concern the groove.

[0053] In the examples shown, the container body 1 is made either of ceramic or porcelain (both glazed or unglazed), or of glass or metal.

Claims

Patent claims 1 . Container for holding foodstuffs, with a container body (1) made of ceramic, porcelain, glass or metal, comprising a base (2), one or more side walls (3) and a surrounding upper container edge (4), characterized in that a surrounding plastic element (12), the upper side (14) of which is exposed, is attached to the container edge (4) by means of an adhesive (11).

2. Container according to claim 1, characterized in that an upwardly open, circumferential groove (6) is provided on the container edge (4), in which groove (6) the plastic element (12) surrounding the groove (6) is fastened by means of the adhesive (11), the upper side (14) of which plastic element is exposed and projects out of the groove (6).

3. Container according to claim 1 or 2, characterized in that the plastic element (12) has a flat upper side (14).

4. Container according to claim 3, characterized in that the plastic element (12) is rectangular in cross-section.

5. Container according to one of the preceding claims, characterized in that the plastic element (12) has a thickness of at least 1.5 mm, preferably of at least 2.5 mm.

6. Container according to claim 5 and claim 2, characterized in that the plastic element (12) protrudes from the groove (6) by at least 1 mm, preferably by at least 2 mm.

7. Container according to one of the preceding claims, characterized in that a plurality of projecting spacers (13) are provided on the plastic element (12) on the side facing the container edge (4).

8. Container according to claim 5, characterized in that the spacers (13) are provided at least in the region of the corners in the case of a plastic element (12) having a rectangular shape and are provided equidistantly distributed over the length in the case of a plastic element (12) having a circular shape.

9. Container according to one of the preceding claims, characterized in that the plastic element (12) is at least partially embedded in the adhesive (11) in a floating manner.

10. Container according to one of the preceding claims and claim 2, characterized in that the groove (6) is at least 1 mm, preferably at least 2 mm wider than the plastic element (12). 11 . Container according to one of the preceding claims, characterized in that the plastic element (12), at least in the area forming the upper side (14), is made of polypropylene or polyethylene terephthalate.

12. Container according to one of the preceding claims, characterized in that the adhesive (11) is elastic in the cured state.

13. Container according to one of the preceding claims, characterized in that the adhesive (11) is a silicone-based mass.

14. Container according to claim 13, characterized in that the mass is a 1-component silicone.

15. A method for producing a container according to any one of the preceding claims, comprising the following steps: Providing a container body (1) comprising a base (2), one or more side walls (3) and a continuous upper container edge (4), Applying the adhesive to the container rim (49), inserting the plastic element (12) into the adhesive (11), curing the adhesive.

16. Method according to claim 15, comprising the following steps: Providing a container body (1) comprising a base (2), one or more side walls (3) and a continuous upper container edge (4), wherein an upwardly open, continuous groove (6) is provided on the container edge (4), Inserting the adhesive (11) into the groove (6), Inserting the plastic element (12) into the groove (6), Curing of the adhesive (11 ).

17. Method according to claim 16, characterized in that the groove is filled with the adhesive to at least 50% of its volume, in particular to at least 70%.

18. Method according to one of claims 15 to 17, characterized in that the plastic element (12) is treated with plasma before insertion.

19. Method according to one of claims 15 to 18, characterized in that the plastic element (12) is pressed into the adhesive (11) by means of a pressure plate.

20. Method according to one of claims 15 to 19, characterized in that a plastic element (12) made of polypropylene or polyethylene terephthalate or high-density polyethylene is used.

21. Method according to one of claims 15 to 20, characterized in that a silicone-based mass, in particular a 1-component silicone, is used as the adhesive (11).

22. A food unit comprising a container according to any one of claims 1 to 14, into which one or more food items are placed, and which is sealed with a sealing film (16) which is attached to the plastic element (12) in a sealing process in a tearable manner.

23. A method for producing a food unit according to claim 22, comprising the following steps: - Providing a container according to one of claims 1 to 14, - applying a sealing film (16) by means of a film sealing device to the plastic element (12) to form a material-locking Connection of the sealing film (16) to the plastic element (12).

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