resealable packaging

Abstract

To provide food packaging that can be opened without leaving any residue and is resealable. [Solution] The packaging includes a packaging container and a multilayer sealing section. The sealing section has at least one carrier layer and one adhesive layer. 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, the second having a lower melting point than the first. The packaging container is made of a third polyolefin plastic, the third having a higher melting point than the second. The packaging container is provided with a substantially planar sealing collar. The adhesive layer of the sealing section adheres to the sealing collar of the packaging container. Furthermore, the sealing section has an elastic clamp structure located in close proximity to the sealing collar.

Description

Technical Field

[0001] The present invention relates to a package including a packaging container and a film-like multilayer seal portion. 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 can be resealed is provided.

Background Art

[0002] For example, in the field of food packaging, it is often the goal to seal an object such as a container (e.g., a cup, a bucket, a barrel, etc.). It is known to provide a seal collar in the form of a collar-shaped edge along the opening for such a container as the object. And a sealing component for sealing, for example, as a lid, is attached to this edge. The lid can be manufactured from various materials and can also be attached in various ways. Among the available methods are, in particular, adhesion, pressure bonding, welding, etc. The selected materials and methods each bring specific advantages, but often also have corresponding disadvantages, so 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 purity of varieties is often required for the entire package. In this regard, both the container (such as an object like a cup) and the seal (lid) are often required to be manufactured from sufficiently similar or the same materials in order to enable easy recycling at the time of disposal. However, particularly in the field of consumer goods, other factors also need to be considered. 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] From the perspective of 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 a perishable food.

[0006] Therefore, in relation to packaging containers that constitute the packaging of the contents to be filled, there is a need for technology to achieve the above objectives, particularly when applying sealing components. In doing so, economy, reliability, and overall satisfactory compliance with all applicable standards should also be considered. Accordingly, a particular objective of the present invention is to provide sealing components and packaging that can achieve one or more of the aforementioned objectives. [Overview of the project]

[0007] The aforementioned problems and challenges are resolved by the subject matter of independent claims 1 and 8. 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. The sealing portion has at least one carrier layer and one adhesive layer, the carrier layer being made of a first polyolefin plastic having a first melting point, and the adhesive layer being made of a second polyolefin elastomer or plastomer, the second having a lower melting point than the first. The packaging container is made of a third polyolefin plastic, the third having a higher melting point than the second. The packaging container is provided with a substantially planar sealing collar. Here, the adhesive layer of the sealing portion adheres to the sealing collar of the packaging container. Furthermore, the sealing portion has an elastic clamp structure at a position spatially close to the sealing collar. [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 a packaging body comprising a packaging container and a multilayer sealing portion according to an embodiment of the present invention. [Figure 2A] Figure 2A shows a schematic cross-sectional view of the packaging portion according to a general embodiment of the present invention. [Figure 2B] Figure 2B shows a schematic cross-sectional view of the packaging portion according to a general 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. The seal portion 1 has 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 lower than the first melting point T1. The packaging container 2 is made of a third polyolefin plastic having a third melting point T3 higher than the second melting point T2, and includes a seal color 20 having a substantially planar seal color 200. The adhesive layer 102 of the seal portion 1 adheres to the seal color 20 of the packaging container 2. The seal portion 1 has an elastic clamp structure 120. In the closed state, the elastic clamp structure 120 can be positioned spatially close to the seal color 200. As a result, at least in the closed state, the seal portion 1 has the elastic clamp structure 120 in spatial proximity to the seal collar 200.

[0012] Figure 1 shows a schematic diagram of the interaction between a sealing portion in the form of a lid 1 according to an embodiment of the present invention and a packaging container in the form of a cup 2. As shown in the figure, a molded article of the aforementioned material forms the lid 1 for the cup 2, and the lid 1 is also applied to the edge or collar 20 of the cup 2, which has a sealing collar 200, as an exemplary object. This edge 20 can form an annular sealing collar. That is, this annular collar completely seals the cup opening, and the collar shape means a radial extension of sufficient width. Conventional annular sealing collars are about 5 cm to 15 cm in diameter and several millimeters in width. Thus, the illustrated cup 2 and lid 1 form a packaging body consisting of a volume-retaining container and a sealing portion according to one of the above-described configurations. The volume-retaining container is closed at least in part along the sealing collar, for example along the edge or sealing collar of the cup, by 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 cup's rim 20, thereby ensuring a sufficiently large, preferably maximum, surface contact (contact area). This forms an adhesive bond that ensures sufficient airtightness as product packaging, allows for opening without leaving any residue (see lower enlarged view), and, due to its stable shape, allows 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 the seal color 20 of the packaging container 2. This effectively prevents welding between the seal portion 1 and the packaging container 2, i.e., adhesion that is difficult to remove or reseal. Furthermore, simultaneous deformation of the adhesive layer 102 and the seal color surface is also prevented. This can 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 so that the foreign matter content of one is a maximum of 5% 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] In embodiments of the present invention, the lid 1 further includes an elastic clamp structure 120 positioned adjacent to the seal collar 20 as a sealing portion. In particular, in this case, the elastic clamp structure 120 may have an annular spring structure. That is, for example, a projection 121 (see enlarged view on the left) is provided along the circular opening of the cup 2, which is elastically deformable. This is achieved, for example, by providing a thin-walled portion 122 relative to the material thickness of the other part of the lid 100'. This forms a clamp connection with the cup 2 and ultimately provides reliable resealability. The shape of the elastic clamp structure 120 is adjustable to the shape of the seal collar 110. That is, in this case, both are circular or annular. In this respect, the annular shape is generally a closed shape, but it does not necessarily have to be circular, and may rather be elliptical, rectangular, rounded quadrilateral, etc. In general, the shape of the elastic clamp structure 120 can basically follow the shape of the seal collar 110.

[0017] Figures 2A and 2B show schematic cross-sectional views of a multilayer seal portion according to an embodiment of the present invention. These figures show a layer profile 100 for forming packaging applicable to an object. For example, it can be applied to an object, such as a packaging container, using tools under the effects of heat, pressure, and / or ultrasound. In a preferred embodiment, the layer profile is used, for example, in combination with a cup 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 layer profile 100 is configured for application to an object and includes 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. Thus, 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.

[0018] 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 particularly allows the layer profile 100 to be applied to the object on the side of the adhesive layer 102. Thus, the adhesive layer 102 is not fully accessible because it is covered by the seal color of the object or packaging container. However, the solution of 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.

[0019] 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.

[0020] This deformability allows for particularly reproducible formation of adhesive bonds with corresponding surfaces of objects. This is distinct from welding or 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 or thread-like packaging residue on food packaging. This is often perceived as a significant disadvantage because consumers are concerned about food contamination from packaging residue.

[0021] According to the corresponding embodiment of the present invention, the first removal force for initially removing the multi-layer seal portion from the seal collar 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. Initial removal refers to the process of starting to open the multi-layer seal portion from a completely closed state. The initial removal can continue until the state where the package can be accessed for the first time. This first removal force is generally larger than other forces to be considered during opening because the opening line may be larger at the initial stage of the opening process than at later stages.

[0022] 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 packaging container. This advantageous combination of layer thickness and melting point / sealing temperature 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, it is preferable that the carrier layer 101 is thicker than the adhesive layer 102.

[0023] As shown in FIG. 2B, the seal portion 1 includes, in a pre-stage, a seal collar 110 having a substantially planar surface for applying the seal collar of the packaging container to the seal collar. Specifically, the seal collar 110 has a surface that can establish surface contact with a corresponding mating surface 200 on the packaging container, and at least a surface contact for forming an adhesive bond is provided in a part of this contact surface. In particular, this planar shape provides symmetry and enables simplification of the attachment of the seal component to the packaging container. For example, when the seal component and the corresponding seal collar are circular, the substantially planar surface allows the seal component to be attached at any rotation angle along the common rotation axis with the packaging container.

[0024] The seal part 1 further includes an elastic clamping structure 120 at a position closer to the seal collar. The clamping structure 120 is, for example, a raised portion or a protrusion in the cross-section of the seal part 100, and increases the peripheral length compared to the cross-section without the raised portion or the protrusion. Therefore, the elastic clamping structure 120 can be configured to provide clamping adhesion to the packaging container in particular (see also Fig. 1). The elasticity of the clamping structure is advantageously provided by the material system of the carrier layer and the adhesive layer, and its structure can extend along the entire seal part 100.

[0025] Fig. 3 schematically shows a measuring device capable of reproducibly measuring the opening force. An example of this measuring device is publicly available on the Internet as follows and can be accessed. 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

[0026] This measuring device includes a group of rollers 31, and a sample (i.e., the sealed package V according to the present invention) can be pressed on the slide 32 below it. 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. Thereby, the package is opened, the lid (seal part) is peeled upward, and the peeling force can be measured in the process of the package moving correspondingly on the slide 32 (in this case, in the right [R] direction). In the initial stage, the package is opened along a relatively long opening line, but then the opening line is reduced 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. 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 causing breakage or damage of the film 100.

[0027] Generally, the film according to the present invention forms packaging that can be opened without leaving any residue. Similar considerations apply to resealability, as in many cases, resealing is impossible because the packaging components are damaged upon opening. In contrast, the film according to the present invention can form packaging that does not break or break when peeled (for example, when peeled from a cup-shaped object) and maintains its shape stably. This shape stability is sometimes essential for the adhesive surface to be able to be re-adhered (albeit with reduced strength) when resealing the packaging.

[0028] 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 coordinated with each other so 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 portion of the object. This advantageous combination of layer thickness and melting point enables highly reliable processing tailored 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 in the range of, for example, 1:1 to 20:1. Therefore, it is preferable that the carrier layer 101 is thicker than the adhesive layer 102.

[0029] Generally, the heat input required for heating via the carrier layer 101 and the second melting point T2 can be set such that the adhesive layer 102 deforms, increasing the surface contact area with at least a portion of the seal collar of the object. In this respect, the adhesive layer 102 may melt or begin to melt at least partially. This temperature may be close to or above 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 temperature and performance profile over time at which adhesive bonding with the object is achieved, and whether or not there is heat input. This ensures complete contact between the surface of the adhesive layer 102 and the surface of the object. In other words, the surface shape of the adhesive layer 102 in the applied state conforms to the shape of the object within the sealing region (e.g., the annular collar along the edge of a cup).

[0030] 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.

[0031] Figure 4 shows a schematic cross-sectional view of a multilayer seal component in the form of a layered structure according to another embodiment of the present invention. Thus, the layered structure 100' again includes layers 101 and 102 as described above. In this embodiment, the layered structure 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 co-extrusion process and the printability of the layered structure 100' are particularly improved. If necessary, the additional layer 103 can also be embossed P.

[0032] Generally, the packaging components according to the described embodiments replace conventionally used aluminum lids. In the case of polypropylene cups, the lid can be recycled together with the cup. The adhesive layer may provide a release layer made of a low-heat-sealable polyolefin elastomer or plastomer, i.e., a material 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. In other words, both relatively loosely sealed packaging and relatively tightly sealed packaging can be provided. For example, a yogurt cup can be easily opened by a child's hand, while pet food, for instance, may require more force to open.

[0033] Furthermore, an advantage of this layered structure lies in its low sealing or closing temperature. This means that the layered structure can be applied to the object at a relatively low temperature (compared to conventional techniques). This temperature range can even be below the temperature range at which the printing ink of a directly printed lid decomposes or breaks down. In addition, the flexible adhesive layer can compensate for dimensional errors of the sealing tool relative to the cup, and a uniform peeling and pulling force is obtained across the entire sealing surface along the seal color when opening. The described sealing components can be manufactured from corresponding precursor films or plates, or by injection molding. In the latter case, the materials for layers 101, 102 and any additional layers are sequentially injected into the mold cavity using known techniques.

[0034] 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 package comprising a packaging container and a multi-layer seal portion, The sealing portion comprises at least one carrier layer and one adhesive layer. 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 made of a third polyolefin plastic having a third melting point higher than the second melting point, and is equipped with a seal collar having a planar seal collar. The adhesive layer of the sealing portion is adhered to the seal color of the packaging container. The sealing portion is a packaging body having an elastic clamp structure located spatially close to the sealing collar.

2. The packaging body according to claim 1, wherein the elastic clamp structure is configured to provide clamp adhesion to the packaging container.

3. The packaging body according to claim 1 or 2, wherein the elastic clamp structure has an annular spring structure.

4. The packaging body according to any one of claims 1 to 3, wherein the shape of the elastic clamp structure is adjusted to conform to the shape of the seal collar.

5. The packaging body according to claim 4, wherein the shape of the elastic clamp structure essentially conforms to the shape of the seal collar.

6. The carrier layer has a first layer thickness, The aforementioned adhesive layer has a second layer thickness, The packaging according to any one of claims 1 to 5, 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 color of the packaging container by heat input through the carrier layer.

7. The packaging according to claim 6, wherein the heat input through 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.

8. 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 7, 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.

9. 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 8, wherein the first melting point is at least 10°C, preferably at least 20°C, higher than the second melting point.

10. The third melting point is in the range of 150°C to 165°C. The packaging according to any one of claims 1 to 9, wherein the third melting point is at least 10°C, preferably at least 20°C, higher than the second melting point.

11. The packaging according to any one of claims 1 to 10, 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.

12. The packaging according to any one of claims 1 to 11, wherein the material system of the adhesive layer, the carrier layer and the packaging container is based on polypropylene and / or polyethylene.

13. The packaging according to any one of claims 1 to 12, wherein the multilayer sealing portion includes an additional layer on the carrier layer.

14. At least in the region of the seal color, the contact area between the multilayer seal portion and the seal color is maximized. The packaging body according to any one of claims 1 to 13, wherein the seal collar of the seal portion forms an adhesive bond with at least a portion of the seal collar of the packaging container.

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