Packaging consisting of a packaging container and a multi-layer sealing section

Abstract

Food packaging is provided that can be opened without leaving any residue and / or resealed. [Solution] The packaging comprises a packaging container and a multilayer sealing portion having at least one carrier layer and one adhesive layer. The adhesive layer of the sealing portion adheres to the sealing color of the packaging container. The carrier layer is made of a first polyolefin plastic having a first melting point, and the adhesive layer is made of a second polyolefin elastomer or plastomer having a second melting point lower than the first melting point. The packaging container is made of a third polyolefin plastic having a third melting point higher than the second melting point.

Description

Technical Field

[0001] The present invention relates to a package including a packaging container and a film-like multilayer seal part. This film can be applied to the seal collar of the packaging container using a tool utilizing heat and / or pressure. In a preferred embodiment, a food package that can be opened without leaving residues and / or can be resealed is provided.

Background Art

[0002] For example, in the field of food packaging, it is often the purpose to seal an object such as a container (e.g., a cup, a bucket, a barrel, etc.). A method is known in which a collar-shaped edge is provided along the opening of the container as the object, and a film lid is attached to this edge for sealing. The lid can be manufactured from various materials and can also be applied by various methods. Among the available methods are, inter alia, adhesion, crimping, welding, etc. The selected materials and methods each bring specific advantages, but often have corresponding disadvantages, and therefore the selection of materials and methods for specific applications and purposes is often restricted.

[0003] In recent years, further problems have arisen, particularly in the packaging of consumer goods (such as food, pharmaceuticals, cosmetics, consumables, etc.). For example, in order to ensure sufficient recyclability, a certain variety purity is often required for the entire package. In this regard, it is often required that both the container (such as an object like a cup) and the seal (lid) be manufactured from sufficiently similar or identical materials in order to enable easy recycling at the time of disposal. However, in the consumer goods field in particular, other factors also have to be taken into account. Good printability of the material, compliance with hygiene regulations, and a satisfactory opening experience for the user are mentioned here.

[0004] The latter is especially important in the food industry. Users (consumers) need to feel safe knowing, firstly, that the container was securely closed before opening, and secondly, that the container was undamaged after opening and that the seal was properly opened. This means being able to completely remove the lid without leaving any residue, and / or having good and reliable resealability.

[0005] Regarding compliance with hygiene standards and regulations, the outside of food packaging must not be contaminated with the contents (food) as a result of the filling and sealing process, nor must the tools and equipment used in packaging be contaminated with the contents or the material being filled. For example, residue remaining on the outside of packaging not only gives an impression of uncleanliness but can also spoil or contaminate other products. Contamination of the filling plant itself (including tools, holders, conveying mechanisms, etc.) is also often undesirable, especially when the material being filled is perishable food.

[0006] Therefore, when applying a film-like multilayer seal to a packaging container, particularly in relation to the packaging of the contents to be filled, a technology is needed to achieve the above objectives. In doing so, economic efficiency, reliability, and overall satisfactory compliance with all applicable standards should also be considered. Accordingly, a particular objective of the present invention is to provide a packaging that can achieve one or more of the aforementioned objectives. [Overview of the project]

[0007] The aforementioned problems and objectives are resolved by the subject matter of the independent claims. Further advantageous embodiments of the present invention are described in the dependent claims.

[0008] According to embodiments of the present invention, a package is provided comprising a packaging container and a multilayer sealing portion having at least one carrier layer and one adhesive layer. The adhesive layer of the sealing portion adheres to the sealing collar of the packaging container. The carrier layer is made of a first polyolefin plastic having a first melting point, and the adhesive layer is made of a second polyolefin elastomer or plastomer having a second melting point lower than the first melting point. The packaging container is made of a third polyolefin plastic having a third melting point higher than the second melting point. [Brief explanation of the drawing]

[0009] Embodiments of the present invention are described and illustrated in particular with reference to the following drawings. The scope of protection should not be limited to these embodiments, and therefore the drawings and corresponding descriptions are for illustrating the general concept of the invention. The accompanying drawings are as follows:

[0010] [Figure 1] Figure 1 shows a schematic diagram of packaging comprising a packaging container and a multilayer sealing portion according to an embodiment of the present invention. [Figure 2] Figure 2 shows a schematic cross-sectional view of a film-like multilayer sealing portion according to an embodiment of the present invention. [Figure 3] Figure 3 shows a schematic diagram of a measuring device that can reproducibly measure opening force. [Figure 4] Figure 4 shows a schematic cross-sectional view of a film-like multilayer sealing portion according to another embodiment of the present invention. [Modes for carrying out the invention]

[0011] Figure 1 shows a schematic diagram of a package comprising a packaging container and a multilayer seal portion according to an embodiment of the present invention. As shown in the figure, the package V comprises a packaging container 2 and a multilayer seal portion 1 in film form. The seal portion 1 and the corresponding film as a semi-finished product each have at least one carrier layer 101 and one adhesive layer 102, the adhesive layer 102 of the seal portion 1 adhering to the seal collar 20 of the packaging container 2 when the package V is closed or at least partially closed. The carrier layer 101 is made of a first polyolefin plastic having a first melting point (T1), and the adhesive layer 102 is made of a second polyolefin elastomer or plastomer having a second melting point (T2). In this respect, the second melting point T2 is lower than the first melting point T1. The packaging container 2 is further made of a third polyolefin plastic having a third melting point (T3), the third melting point T3 being higher than the second melting point T2.

[0012] Figure 1 schematically illustrates the details of the interaction between a molded film seal portion 1 and an object, a packaging container. Here, a molded product formed from film 100 forms a lid as a seal portion 1 for a cup 2, which is a packaging container. The film 100 of the lid is applied to the seal collar or rim 20 of the exemplary packaging container, the cup 2. This seal collar 20 can form an annular seal collar. That is, this annular seal collar completely seals the cup opening, and the collar shape means a radial extension of sufficient width. Conventional annular seal collars have a diameter of approximately 5 cm to 15 cm and a width of several mm. Thus, the illustrated cup 2 and lid 1 form a package consisting of a volume-retaining container and film. The volume-retaining container is closed along the seal collar, for example, along the rim of the cup, and a portion of it is fixed by at least adhesive bonding.

[0013] This is particularly illustrated by the upper enlarged view showing the interface between the adhesive layer 102 and the surface of the packaging container 2. The adhesive layer 102 is deformed so that its surface conforms to the surface structure of the seal collar 20, thereby ensuring a sufficiently large, preferably maximum, surface contact (contact area). This creates an adhesive bond that ensures sufficient airtightness for product packaging, while at the same time allowing opening without leaving any residue (see lower enlarged view) and, due to its stable shape, allowing the packaging to be resealed at least partially.

[0014] This advantageous bond, namely the sealing properties of the packaging, is achieved, in particular, by the fact that the first melting point T1 is higher than the second melting point T2, and the third melting point T3 is also higher than the second melting point T2. The following relationship holds: T1>T2 <T3; Therefore, the adhesive layer 102 can be heated to the point of softening or partial melting without significantly softening, deforming, or melting the carrier layer 101 or seal color 20 of the packaging container. This effectively prevents welding between the seal portion 1 and the packaging container 2, i.e., a bond that is difficult to remove or reseal. Furthermore, simultaneous deformation of the adhesive layer 102 and the surface of the seal color is also prevented. This could potentially lead to a strong bond even without welding.

[0015] It is preferable that the material system of the carrier layer, adhesive layer, and packaging container is based on polypropylene. In a preferred embodiment, all elastomers, plastomers, and / or ternary copolymers of the layers of the film 100, for example, layers 101 and 102, are polypropylene-based. That is, the base polymer of the materials for these layers is polypropylene. Alternatively, the material system of the carrier layer, adhesive layer, and container may be based on polyethylene. The object or volume-holding container 2 is also made of polyolefin-based plastic. This favorably promotes adhesive bonding when surface contact between the film and the polyolefin-based plastic of the container is maximized, at least in the seal color area. Furthermore, these embodiments ensure the variety purity of the packaging, which has essential and advantageous significance, particularly from the viewpoint of reuse, recycling, and sustainability. Preferably, the material system of the film and the material system of the volume-holding container are adjusted to each other such that one contains a maximum of 5% foreign matter by weight relative to the other. This ensures particularly good variety purity, and the packaging can be disposed of as a whole, or the container and lid together.

[0016] Figure 2 shows a schematic cross-sectional view of a film-like multilayer sealing portion according to an embodiment of the present invention. This shows a packaging-forming film 100 that can be applied to an object as a packaging container. For example, it is formed as a packaging container by applying heat, pressure, and / or ultrasound to the object using a tool. In a preferred embodiment, this film is used, for example, in combination with cups to form food packaging, dairy product packaging (e.g., yogurt cups), dairy substitute product packaging, sausage or meat product packaging, cooked food packaging, pet food packaging, etc. The film 100 is configured for application to an object and comprises at least one carrier layer 101 and one adhesive layer 102. The carrier layer 101 is made of a first polyolefin plastic having a first melting point T1, and the adhesive layer 102 is made of a second polyolefin elastomer or plastomer having a second melting point T2. In this respect, the second melting point T2 is lower than the first melting point T1. Therefore, the following relationship holds: T1 > T2. Examples of polyolefin plastics include polypropylene (PP) and polyethylene (PE). The adhesive layer 102 may, in particular, include an elastomer and / or plastomer, or be composed of either of these materials or a corresponding combination thereof. In addition to the elastomer and / or plastomer, the adhesive layer 102 may include a ternary copolymer to reduce the tendency to adhere. That is, this prevents adhesion and allows adhesion to the object in order to achieve the aforementioned advantages.

[0017] The adhesive layer 102 is in a molten state, a partially molten state, or at least a deformable state within limits. The configuration of the present invention makes it possible to adhere the film 100 to an object using the surface of the adhesive layer 102. Therefore, the adhesive layer 102 is covered by the seal color of the object or packaging container and is not fully accessible. However, the solution according to the present invention allows sufficient heat input through the upper carrier layer 101. This is because the melting point T1 of the carrier layer 101 is higher than the melting point T2 of the adhesive layer 102. With the adhesive layer 102 already in contact with the object, the layer is heated and becomes molten, partially molten, or at least deformable. Deformability here means greater deformability at temperatures under heat input compared to deformability at room temperature, usage temperature, and storage temperature.

[0018] This deformability does not necessarily refer to macroscopic deformation visible to the naked eye, but rather to microscopic adaptation to the roughness of the object (e.g., the contact surface of the seal color) while forming adhesion and a corresponding seal. Because the melting point T1 is high, the carrier layer 101 can reliably hold the adhesive layer 102 even in a deformed state, thereby enabling highly reliable and practical processing. Since the melting point T3 is also higher than the second melting point, the fine surface of the seal color remains sufficiently stable, allowing adaptation of the single-sided surface and interface to proceed, and a favorable adhesive bond to be formed.

[0019] This deformability allows for particularly reproducible formation of adhesive bonds with corresponding surfaces of objects. This is distinct from welding and bonding, which do not require optimal surface fit between the objects being bonded, but typically form bonds that are too strong. In particular, the force required to release adhesive or welded bonds may be greater than the force required to release internal bonds within the layered structure of the packaging film used. As a result, such packaging often "tears" upon opening, leaving fragments and thread-like packaging residue on food packaging. This is often considered a significant disadvantage because consumers are concerned about food contamination from packaging residue.

[0020] According to corresponding embodiments of the present invention, the first removing force for initial removal of the multilayer seal portion from the seal collar of the packaging container is preferably in the range of 10N to 20N, and the second removing force for further removal is preferably in the range of 1N to 5N. Initial removal refers to the process of initiating the opening of the multilayer seal portion from a fully closed state. Initial removal may continue until the package becomes accessible for the first time. This initial removing force is generally greater than other forces to consider during opening because the opening line may be larger in the initial stages of the opening process than in later stages.

[0021] Figure 3 schematically shows a measuring device that can reproducibly measure opening force. An example of this measuring device is publicly available on the internet and can be accessed as follows. https: / / web.archive.org / web / 20240430080932 / https: / / www.zwickroell.com / fileadmin / content / Files / SharePoint / user_upload / PI_DE / 10_611_Deckel_Abziehvorrichtung_fuer_peelbare_Verpackungen_PI_DE.pdf

[0022] This measuring device includes a roller group 31, and under it, a sample (i.e., the sealed package V according to the present invention) can be pressed against the slide 32. For example, using a force measuring device 33, a vertically upward force F is applied to the opening flap 10 of the multi-layer seal part 1. As a result, the package is opened, the lid (seal part) is peeled upward, and during the process in which the package moves appropriately on the slide 32 (in this case, in the right [R] direction), the peeling force can be measured. In the initial stage, the package is opened along a relatively long opening line, but then the opening line shrinks to a relatively short line. This is due to the shape of the annular seal collar. The illustrated opening lines are drawn as virtual lines L and l, which correspond to the corresponding lines at each opening time point. According to an embodiment of the present invention, the peeling force throughout the opening process is within the above range and is always smaller than the force for peeling the adhesive layer 102 from the carrier layer 101 or the force that causes breakage or damage to the film 100.

[0023] Generally, the film according to the present invention forms a package that can be opened without leaving residues. Similar considerations also apply to resealability. Since the packaging parts are damaged during opening, resealing is often impossible. In contrast, the film according to the present invention can form a package that does not break or damage during peeling (for example, when peeling from a cup-shaped object) and maintains a stable shape. This shape stability may be essential when resealing the package because the adhesive surface can be adhered again (although the strength decreases).

[0024] Preferably, the carrier layer 101 has a first layer thickness d1, and the adhesive layer 102 has a second layer thickness d2. The first layer thickness d1 and the second layer thickness d2 are adjusted relative to each other such that the heat input through the carrier layer 101 causes deformation of the adhesive layer 102 while forming an adhesive bond with at least a partial region of the object. This advantageous combination of layer thickness and melting point enables highly reliable processing adapted to the object. In this regard, the first layer thickness d1 may be in the range of 10 μm to 600 μm, and the second layer thickness d2 may be in the range of 5 μm to 30 μm. Alternatively, the ratio of the first layer thickness d1 to the second layer thickness d2 can be set, for example, in the range of 1:1 to 20:1. Therefore, the carrier layer 101 is preferably thicker than the adhesive layer 102.

[0025] Generally, the heat input required for heating through the carrier layer 101 and the second melting point T2 can be set such that the adhesive layer 102 increases the surface contact area with at least a partial region of the seal collar of the object while deforming. In this regard, the adhesive layer 102 may at least partially melt or may start to melt. This temperature may be close to or higher than the second melting point T2. Therefore, the properties of the carrier layer 101 and the adhesive layer 102, particularly the melting point T2, determine the presence or absence of heat input over time of the temperature and performance profile for achieving an adhesive bond with the object. In this case, it is possible to maximize the increase in surface contact. Thereby, the contact between the surface of the adhesive layer 102 and the surface of the object becomes complete. That is, in particular, the surface shape of the adhesive layer 102 in the applied state follows the shape of the object within the seal region (e.g., an annular collar along the edge of the cup).

[0026] Preferably, the first melting point T1 of the carrier layer 101 is in the range of 100°C to 160°C, and the second melting point T2 of the adhesive layer 102 is in the range of 40°C to 90°C. Furthermore, it is desirable that the third melting point T3 of the packaging container or seal color material be in the range of 150°C to 165°C. Generally, the first melting point T1 may be at least 10°C, preferably at least 20°C, higher than the second melting point T2. Thus, in the material system in question, good deformability of the adhesive layer 102 can be achieved while maintaining the dimensional stability of the carrier layer 101. This is particularly true for material systems of the adhesive layer 102 based on polypropylene and / or polyethylene.

[0027] Figure 4 shows a schematic cross-sectional view of a film-like multilayer seal portion according to another embodiment of the present invention. Thus, the film 100' again includes layers 101 and 102 as described above. In this embodiment, the film 100' includes an additional layer 103 on the carrier layer 101. Preferably, the additional layer 103 is also made of a polyolefin plastic, and its compound or composition is different from that of layers 101 and 102. Furthermore, the melting point T4 of the polyolefin plastic of the additional layer 103 can be set to be at least higher than the second melting point T2. This allows heat input for deformation and adhesion formation of the adhesive layer 102 to be carried out via the carrier layer 101 and the additional layer 103. By providing the additional layer 103, the processability of the film extrusion molding process and the printability of the film are particularly improved. If necessary, the additional layer 103 can also be embossed P.

[0028] Generally, the plastic film according to this embodiment replaces conventionally used aluminum lids. In the case of PP cups, this film is recyclable together with the cup. The adhesive layer 102 may provide a release layer made of a low-temperature sealing polyolefin elastomer or plastomer that melts at a relatively low temperature. For example, when sealing / closing a polypropylene cup, it is particularly advantageous to use a material made of metallocene-catalyzed polypropylene with different ethylene content. This provides particularly advantageous complete recyclability of the PP cup and lid. A further advantage of using the described layer is that the release force (removal force) can be individually adjusted depending on the time, temperature, and pressure at the time of application. That is, both relatively loosely sealed packaging and relatively tightly sealed packaging can be provided. For example, yogurt cups can be easily opened even by a child's hand, while pet food may require more force to open.

[0029] A further advantage of this film lies in its low sealing temperature. This means that the film can be applied to the object at a relatively lower temperature compared to conventional techniques. This temperature range can even be below the temperature range at which the printing ink on directly printed lids decomposes or is destroyed. In addition, the flexible adhesive layer can compensate for dimensional errors of the sealing tool relative to the cup, and a uniform peel-out force is obtained across the entire sealed surface along the seal color when opening, which is another advantage.

[0030] The above describes detailed embodiments of the invention, but these are merely for the purpose of better understanding the invention and its effects. The scope of protection is defined by the following claims and is not limited by the detailed description.

Claims

1. A packaging body comprising a packaging container and a multilayer sealing portion having at least one carrier layer and one adhesive layer, The adhesive layer of the sealing portion is adhered to the seal color of the packaging container. The carrier layer is made of a first polyolefin-based plastic having a first melting point. The adhesive layer is made of a second polyolefin-based elastomer or plastomer having a second melting point lower than the first melting point. The packaging container is a packaging body made of a third polyolefin-based plastic having a third melting point higher than the second melting point.

2. The carrier layer has a first layer thickness, The aforementioned adhesive layer has a second layer thickness, The packaging body according to claim 1, wherein the thickness of the first layer and the thickness of the second layer are adjusted to each other so that the adhesive layer forms an adhesive bond with the seal collar of the packaging container by heat input through the carrier layer.

3. The packaging according to claim 2, wherein the heat input via the carrier layer and the second melting point are set such that the adhesive layer deforms and increases the contact area with at least a portion of the seal color of the packaging container.

4. The thickness of the first layer is in the range of 10 μm to 600 μm. The thickness of the second layer is in the range of 5 μm to 30 μm, and / or The packaging according to any one of claims 1 to 3, wherein the ratio of the thickness of the first layer to the thickness of the second layer is in the range of 1:1 to 20:

1.

5. The first melting point is in the range of 100°C to 160°C. The second melting point is in the range of 40°C to 100°C, and The packaging according to any one of claims 1 to 4, wherein the first melting point is at least 10°C, preferably at least 20°C, higher than the second melting point.

6. The third melting point is in the range of 150°C to 165°C. The packaging according to any one of claims 1 to 5, wherein the third melting point is at least 10°C, preferably at least 20°C, higher than the second melting point.

7. The packaging according to any one of claims 1 to 6, wherein the first removal force for initially removing the multilayer seal portion from the seal color of the packaging container is in the range of 10 N to 20 N, and preferably the second removal force for further removal is in the range of 1 N to 5 N.

8. The packaging according to any one of claims 1 to 7, wherein the material system of the adhesive layer, the carrier layer and the packaging container is based on polypropylene and / or polyethylene.

9. The packaging according to any one of claims 1 to 8, wherein the multilayer sealing portion includes an additional layer on the carrier layer.

10. The packaging according to any one of claims 1 to 9, wherein the contact area between the multilayer seal portion and the seal color is maximized in at least the region of the seal color.

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