Flexible packaging layer material comprising a paper layer, a large-area barrier layer, and an additional localised barrier coating

Abstract

The invention relates to a packaging layer arrangement (10) for producing a packaging container, the packaging layer arrangement comprising: - a paper layer (12) as a carrier layer; - a metal-based barrier layer (22) carried by the paper layer (12); and - a sealable barrier layer (24) arranged on the side of the metal-based barrier layer (22) facing away from the paper layer (12). According to the invention, a sealable additional barrier coating (26) is arranged only locally on the sealable barrier layer (24) in at least one additional barrier surface region (29), wherein the additional barrier surface region (29) is smaller than the area of extent of the sealable barrier layer (24), meaning that at least one further surface region (31) of the sealable barrier layer (24) is free from the additional barrier coating (26).

Description

[0001] Flexible packaging layer material with paper layer, large-area barrier layer and additional local barrier application

[0002] Description

[0003] The present invention relates to a flexible packaging layer arrangement for producing a flexible packaging container, such as a packaging bag. The present invention also relates to a flat blank formed from such a flexible packaging layer arrangement, such as a sheet or blank, for forming a flexible packaging container, such as a packaging bag. Finally, the present invention relates to a flexible packaging with a packaging wall formed at least partially, preferably entirely, from the packaging layer arrangement. However, it should also not be excluded that the present packaging layer arrangement can be used for wrapping products to be packaged.

[0004] The packaging layer arrangement comprises: a paper layer as a carrier layer, a meta II based barrier layer carried by the paper layer, and a sealable barrier layer arranged on the side of the metal-based barrier layer facing away from the paper layer.

[0005] At the beginning of the production of a packaging, the packaging layer arrangement can be in the form of a roll or as a sheet, in particular as a stack of sheets, for the production of a packaging.

[0006] Such a packaging layer arrangement is known from DE 10 2021 103 879 A1. In principle, the packaging layer arrangement known from DE 10 2021 103 879 A1 exhibits a good barrier effect while simultaneously being environmentally friendly. Another packaging layer arrangement with a paper carrier layer carrying barrier layers made of vinyl alcohol polymer and vapor-deposited metal or metal oxide is known from WO 2022 / 258830 A1.

[0007] The object of the present invention is to further improve the barrier properties of the packaging layer arrangement known from DE 10 2021 103 879 A1 without excessive additional resource consumption.

[0008] The present invention achieves the stated object with a packaging layer arrangement mentioned above in that a sealable additional barrier coating is arranged on the sealable barrier layer only locally in at least one additional barrier surface area. The additional barrier surface area is smaller than the extension area of ​​the sealable barrier layer, so that at least one further surface area of ​​the sealable barrier layer is free of the additional barrier coating. In the further surface area, the sealable barrier layer therefore does not bear any additional barrier coating.

[0009] The additional barrier order can therefore be specifically provided locally only where it is actually needed.

[0010] Due to the paper backing layer, the packaging layer arrangement allows for sharp creases and folds, which can place mechanical stress on the existing barrier layers, especially with repeated bending and / or folding, leading to local failure. While this usually only results in very small defects in the barrier layers, the integrity of the barrier layers is at risk of being fundamentally compromised.

[0011] The additional barrier layer can be applied locally at locations subject to high mechanical stress, such as areas with kinks or strong curvatures, and thus counteracts any impairment of the barrier effect of the packaging layer arrangement. This counteracting effect is essentially achieved through two different mechanisms: firstly, the layer thickness of a layer with a barrier effect is simply increased where the additional barrier layer is present. Secondly, the arrangement of the additional barrier layer has a stabilizing effect on the sealable barrier layer supporting it. This is because the additional barrier layer arranged above the sealable barrier layer prevents or reduces the resulting stretching of the sealable barrier layer under a given load and thus delays the onset of material failure of the sealable barrier layer due to the mechanical stress acting on the packaging layer arrangement.

[0012] A "barrier layer" within the meaning of the present application is a layer which, compared to a layer of polypropylene of the same thickness, has an oxygen transfer rate that is 20% lower according to DIN 53380-3 at 23 °C and 50% relative humidity and / or a water vapor transfer rate that is 20% lower according to DIN EN ISO 15106-3 at 38 °C and 90% relative humidity, relative to the reference layer made of polypropylene.

[0013] Preferably, the packaging layer arrangement has an oxygen transfer rate of not more than 1.1 cm 3 / (m 2 -d-bar), determined according to DIN 53380-3 at 23 °C and 50 % relative humidity, and a water vapor transfer rate of not more than 1.1 g / (m 2 -d), determined according to DIN EN ISO 15106-3 at 38 °C and 90 % relative humidity.

[0014] The paper layer as a carrier layer allows for excellent recyclability. Through defibration, at least the fiber portion of the paper layer can be recovered and converted into pulp and processed into a fiber material. It is therefore particularly sustainable.

[0015] The term "paper" refers to any material that falls under the paper definition of DIN 6730. The paper layer preferably has a basis weight in the range of 30 to 100 g / m 2 particularly preferably in a range of 45 to 90 g / m 2 in order to provide sufficient stability as a support layer for the packaging layer arrangement on the one hand and to avoid excessive weight of the packaging layer arrangement on the other hand.

[0016] Tests have shown that natural white, translucent glassine paper or coated paper with a very smooth and dense surface are particularly, but not exclusively, suitable papers. As a carrier layer, such paper provides the packaging layer arrangement with a solid framework that can support the other layers mentioned. Other paper types are, of course, not excluded.

[0017] The metal-based barrier layer comprises or is a layer of metal and / or a metal oxide. The metal-based barrier layer is preferably formed by vacuum deposition. This is possible for both a metallic barrier layer, such as aluminum, and a metal oxide barrier layer, such as aluminum oxide or silicon oxide. Vacuum deposition allows the formation of a particularly thin metal-based barrier layer, the thickness of which can be adjusted particularly precisely through the vacuum deposition process. The metal-based barrier layer acts particularly well as a water vapor barrier.

[0018] Although it is conceivable to provide only one metal-based barrier layer, within the scope of the present invention, to achieve a particularly high barrier effect, it is possible to form a metal-based barrier layer arrangement with a metal layer and at least one additional metal oxide layer, in particular with a metal layer between two metal oxide layers. The metal layer is preferably an aluminum layer. The at least one metal oxide layer can be selected from, for example, an aluminum oxide layer and a silicon oxide layer.

[0019] Preferably, the metal-based barrier layer or the metal-based barrier layer arrangement is between 6 and 50 nm thick. A metal-based barrier layer in the single-digit nanometer range or in the low double-digit nanometer range can be achieved using a pure metal oxide layer. Preferably, a multilayer metal-based barrier layer arrangement has a thickness in the range of 30 to 50 nm, wherein, if the metal-based barrier layer or the metal-based barrier layer arrangement has a metal oxide layer, the metal oxide layer preferably has a thickness of 2.5 to 5 nm. If the metal-based barrier layer arrangement has more than one metal oxide layer, each metal oxide layer preferably has a thickness in the range of 2.5 to 5 nm.

[0020] Expressed in optical density, the metal-based barrier layer or metal-based barrier layer arrangement preferably has a value in the range of 2.0 to 4.0, preferably in the range of 2.2 to 2.8, particularly preferably 2.5. These figures apply to a metal-based barrier layer or a metal-based barrier layer arrangement with one metallic layer. A metal-based barrier layer or a metal-based barrier layer arrangement with only one or more metal oxide layers generally has an optical density of no more than 0.1.

[0021] To ensure that the sealable barrier layer is available for a sealing process, the sealable barrier layer is preferably exposed in at least one further surface area. Particularly preferably, the sealable barrier layer is exposed in the entire further surface area.

[0022] To improve the biodegradability of the packaging layer arrangement, the sealable barrier layer can be formed from a biopolymer, such as at least one polymer selected from PBS (polybutylene succinate), PBSA (polybutylene succinate co-adipate), PLA (polylactide), PCL (polycaprolactone), PHB (polyhydroxybutyrate), PHBV (polyhydroxybutyrate co-valerate), and PBAT (polybutylene adipate terephthalate). These biopolymers are biodegradable according to DIN 13432.

[0023] The sealable barrier layer can also be made of polyethylene, in particular linear low-density polyethylene (LLDPE).

[0024] Preferably, the sealable barrier layer is applied as a continuous, uninterrupted surface, forming a closed surface that completely covers the paper layer lying beneath it from the perspective of the subsequently packaged product. This allows for the widest possible usability of the packaging layer arrangement, since the sealable barrier layer can be heat-sealed to a compatible layer at any location.

[0025] A particularly thin application of the sealable barrier layer can be achieved by applying it as a dispersion. The sealable barrier layer is preferably applied over the entire surface using a roller application. "Full-surface" means that, in the case of rolls, axial edge areas of the roll, which will generate waste during subsequent processing and, for technical reasons, cannot be coated with sealable barrier polymer during production, do not need to be coated in order to still form a full-surface coating. In the case of cut blanks, which are intended to form packaging by folding and / or forming and heat-sealing, a fully applied layer covers the entire surface of the blank.

[0026] The additional barrier layer is intended to provide additional barrier protection only at selected locations on the packaging layer material. The size of the additional barrier surface area is therefore preferably 5% to 25% of the surface area of ​​the sealable barrier layer.

[0027] The additional barrier surface area can be a single contiguous surface area or can be formed by a plurality of separately formed and spaced-apart partial surface areas.

[0028] For the most targeted application of the additional barrier layer, the additional barrier layer is preferably applied as a dispersion. This enables precise printing of the additional barrier material. High precision in the application of the additional barrier material enables the formation of the smallest possible additional barrier surface area, regardless of whether this is formed by a single surface area or by several partial surface areas. An additional barrier material used to form the additional barrier layer can be selected from the materials mentioned above for the sealable barrier layer. For particularly simple, secure, and permanent adhesion of the additional barrier layer to the sealable barrier layer, the additional barrier material is preferably compatible, particularly preferably identical, with the material of the sealable barrier layer.Then an adhesion promoter application between the sealable barrier layer and the additional barrier layer can be avoided.

[0029] The additional barrier coating preferably has an area-related application weight in the range of 2 to 5 g / m 2 Particularly preferably, the additional barrier coating has a surface-related application weight in the range of 3 to 4 g / m 2 on.

[0030] Preferably, the application weight per unit area of ​​the sealable barrier layer is the same as the application weight per unit area of ​​the additional barrier layer. Particularly preferably, the application weight per unit area of ​​the additional barrier layer and the sealable barrier layer differ by no more than 1 g / m 2Such a similar selection of a surface-related application weight for the material of the sealable barrier layer on the one hand and for the additional barrier material on the other hand makes an important contribution to a permanent bond between the sealable barrier layer and the additional barrier layer without the risk of delamination.

[0031] To achieve a structure of the packaging layer arrangement discussed here that is both effective and uncomplicated, the sealable barrier layer is preferably applied directly to the metal-based barrier layer or with only one adhesion promoter layer interposed. Interposing additional polymer layers between the metal-based barrier layer and the sealable barrier layer is possible in principle, but not preferred in this case.

[0032] The sealable barrier layer, as a preferred exposed layer on a package formed from the packaging system arrangement, forms an inner side of the package facing a packaging space of the package. The metal-based barrier layer is therefore preferably arranged between the paper layer and the sealable barrier layer.

[0033] To enable the metal-based barrier layer, preferably deposited in a vacuum, to form on the paper layer with as little disruption and defects as possible, a primer coating is preferably applied between the metal-based barrier layer and the paper layer. The primer coating preferably forms a smoother, free surface for the deposition of the metal-based barrier layer than the paper layer, generally even if the paper layer is coated. Preferably, a material is selected for the formation of the primer coating that has a barrier effect against the migration of oxygen or water vapor. Particularly preferably, a material with an increased oxygen barrier effect is selected for the formation of the primer coating, since the metal-based barrier layer already provides an increased water vapor barrier effect.

[0034] Although the primer coating with oxygen barrier effect can be formed from polyurethane or polyvinylidene chloride in a particularly stable and durable manner, it is preferable for the primer coating to be water-soluble in order to improve the recyclability of the packaging layer arrangement. The water-soluble primer coating with oxygen barrier effect can be dissolved by wetting with water and thus removed from the remaining packaging layer arrangement, in particular from the paper layer. Advantageously, the dissolution of the primer coating can remove the metal-based barrier layer located on the side of the primer coating facing away from the paper layer, as well as the sealable barrier layer supported by the metal-based barrier layer and the additional barrier layer from the paper layer. As a result, the non-fibrous foreign material content during recycling of the paper layer can be further reduced.

[0035] If, however, a primer coating with increased water vapor barrier performance is desired, the primer coating can contain an acrylic copolymer or a polyester as its main component, or, neglecting unavoidable impurities, can consist of an acrylic copolymer or a polyester. The primer coating is preferably applied as a dispersion or solution. The primer coating can be applied by extrusion, printed, or applied with a roller. In any case, the primer coating is preferably applied wet and then dried after application.

[0036] The primer coating preferably has an application weight of 0.9 to 5.5 g / m 2 , particularly preferably from 2 to 4 g / m 2 on.

[0037] Another advantage of the paper layer is its easy and good printability. This allows product information to be easily visible to the consumer through printing, especially multi-color printing, on a package formed by the packaging layer arrangement.

[0038] Once the paper layer is printed, a protective varnish layer can cover the ink layer and thus protect it from external influences, particularly from mechanical abrasion. The protective varnish layer can generally be made of nitrocellulose, polyurethane, polyester, and / or an acrylic copolymer, to name just a few examples. The protective varnish layer preferably has a coating weight, measured in the dry, ready-to-use state, in the range of 0.4 to 2.2 g / m². 2By forming the protective lacquer layer from one of the materials mentioned, the protective lacquer layer can also contribute to the barrier effect of the packaging layer arrangement by acting as a water vapor barrier layer, in addition to protecting the printing ink layer from mechanical abrasion.

[0039] All information on a coating weight or coating weight range in the present application relates to an application in a dry, ready-to-use state, as it exists after 24 hours in an atmosphere with 0% humidity, 1013 hPa and 20 °C.

[0040] As already mentioned at the outset, the present invention also relates to a flexible packaging comprising a packaging wall and a packaging space surrounded by the packaging wall. The packaging wall is formed at least partially, preferably predominantly, and particularly preferably entirely, from a packaging layer arrangement as described and further developed above.

[0041] The package has at least one sealing region in which a portion of the sealable barrier layer of the packaging layer arrangement is connected to another portion of the sealable barrier layer or to a portion of a compatible other layer to form a sealed connection.

[0042] The arrangement of an additional barrier coating is particularly helpful, for example, if the packaging has at least one sealing area which changes its thickness abruptly along its length and / or has a gusset.

[0043] In the area of ​​a thickness jump, where the thickness of the sealing area increases abruptly in one direction along the sealing area, the integrity of the barrier effect of the packaging layer arrangement is compromised, as the opposing regions of the packaging layer arrangement to be sealed together must overcome the change in thickness in a short distance. There is a risk that, in the area of ​​the thickness change, a gusset area of ​​the packaging walls to be sealed together may actually remain unsealed, or that a seal created in the gusset area may only last for a short time and be locally released again due to mechanical stresses in the flexible packaging material.In order to ensure a continuous sealing of the mutually facing and adjacent areas of flexible packaging material in the area of ​​sudden thickness changes, a section of the additional barrier coating is preferably part of the sealing connection of the sealing area.

[0044] A gusset area critical to the integrity of a sealed joint can also arise where more than two surfaces to be sealed meet in a sealing area. Typically, at least two of these surfaces are curved in the gusset area. Therefore, according to a preferred embodiment, the additional barrier coating is applied to the packaging layer material where an area of ​​sudden thickness change and / or a gusset area within the sealing area is expected on the packaging formed from the packaging layer material.

[0045] A particularly common case of a sudden change in thickness in a sealed area of ​​a package is the formation of a layer jump along the sealed area, in which a section of the packaging layer arrangement is folded back on itself. A layer jump always occurs when a virtual boundary exists along the sealed area, on one side of which more layers of packaging layer material are sealed together than on the other side of the virtual boundary. A layer jump occurs, for example, in a so-called "W-fold" used to form a stand-up base on a flexible packaging bag. On one side of the virtual boundary of the sealed area, there are four layers, of which the top two and the bottom two are sealed together inside-to-inside, while the two middle layers face each other with their outer sides and are therefore not sealed together.Such a W-fold allows the packaging fold to be spread to form a standing base of the folded packaging bag. According to a preferred embodiment, in the region of the layer jump, a section of the additional barrier coating is part of the sealing connection of the sealing area. Accordingly, according to this preferred embodiment, the additional barrier coating is applied locally at the point on the flexible packaging layer arrangement where a layer jump is expected in a sealing area.

[0046] However, such layer jumps or sudden changes in thickness are not the only applications for the additional barrier coating described above. The additional barrier coating can also be used without a sealing process to ensure a barrier effect of the packaging in that area of ​​the packaging which is subject to particular stress during use and is therefore particularly susceptible to damage to an unreinforced, sealable barrier layer arrangement. For this purpose, according to a preferred embodiment, the packaging wall can, in addition to or alternatively to the above-mentioned application, have an unsealed section delimiting the packaging space, which is reinforced by the additional barrier coating and in which the additional barrier coating lies unsealed opposite the packaging space.This means that the entire additional barrier coating or an entire partial area of ​​an additional barrier coating formed from several separate and spaced-apart partial areas, although sealable, is not actually subjected to any sealing processing, but is merely applied locally to the packaging layer arrangement as material reinforcement where increased mechanical stresses are to be expected on the packaging formed from it.

[0047] For example, the reinforced packaging wall section bearing the unsealed additional barrier coating can be more strongly curved than an unreinforced packaging wall section adjacent to the reinforced packaging wall section. Likewise, the reinforced packaging wall section can be arranged as a more strongly curved packaging wall section between two adjacent packaging edge sections of lesser curvature and enclosed by them. Such more strongly curved areas can, for example, be the packaging edges connecting two transverse seal seams of a VFFS package (VFFS = "Vertical Form, Fill, and Seal"). During its formation, a VFFS package is filled with a pourable product as the longitudinal seal seam progresses between a lower transverse seal seam and a later upper transverse seal seam. This is just one example of a possible application of an additional barrier coating.

[0048] The present invention is explained in more detail below with reference to the accompanying drawings. It shows:

[0049] Fig. 1 is a roughly schematic cross-sectional view of a first embodiment of a packaging layer arrangement according to the invention,

[0050] Fig. 2 is a roughly schematic cross-sectional view of a second embodiment of a packaging layer arrangement according to the invention, Fig. 3 is a roughly schematic perspective view of a first embodiment of a packaging formed with the packaging layer arrangement of Fig. 1 or Fig. 2, and

[0051] Fig. 4 is a roughly schematic perspective view of a second embodiment of a package formed with the packaging layer arrangement of Fig. 1 or Fig. 2.

[0052] Figure 1 shows a first embodiment of a packaging layer arrangement according to the present invention in a roughly schematic cross-section and designated by 10. In the first embodiment, the packaging layer arrangement 10 comprises a paper layer 12 whose basis weight is preferably not exceeded by any other layer of the packaging layer arrangement 10. The paper layer 12 forms the carrier layer of the packaging layer arrangement 10.

[0053] The representation of the packaging layer arrangement 10 in Figure 1 is expressly not to scale, in particular with regard to the representation of the thicknesses of the individual layers.

[0054] In the illustrated embodiment, a layer 14 of printing inks is applied directly to the paper layer 12 of the packaging layer arrangement 10 toward the outer side 10a of the packaging layer arrangement 10, in the sense of an outer side 10a of a package 40 (see Figure 3) or 140 (see Figure 4) formed from the packaging layer arrangement 10. By applying the printing ink to the layer 14, the packaging layer arrangement 10 and thus the package 40 or 140 formed from it can be provided with product information about the type and / or origin and / or quality and / or quantity of a product packaged with the packaging layer arrangement 10.

[0055] In a particularly simple embodiment of the packaging layer arrangement 10, the layer 14 with the printing ink application can be omitted. In a simple embodiment, the layer 14 with the printing ink application can be an external layer, i.e., one exposed to the surroundings of the packaging layer arrangement 10.

[0056] As a rule, however, it is desirable to permanently maintain the printing ink application in as fresh a quality as possible, since consumers often judge the quality of the packaged product from the easily perceptible visual impression of the packaging. To protect the layer 14 with the printing ink application, a protective layer 16 can therefore be arranged over the printing ink application, covering the printing ink application. The protective layer 16 can comprise a protective varnish, which is preferably applied wet and then dried. A protective varnish applied wet forms a thinner layer 16 when dried than an alternatively laminated protective film made of the same material.

[0057] The protective layer 16 made of nitrocellulose, polyurethane or polyester, to name just a few examples of materials, is preferably provided with an application weight of 0.5 to 2.0 g / m 2 applied.

[0058] A water vapor barrier layer 18 is applied to the side of the paper layer 12 facing the inner side 10b of the packaging layer arrangement 10, opposite the outer side 10a. The water vapor barrier layer 18 can be formed, for example, from an acrylic copolymer or a polyester, for example with an application weight of 1 to 3 g / m 2 , again measured in the ready-to-use dried state.

[0059] The water vapor barrier layer 18 is preferably applied wet and is dried after application.

[0060] An oxygen barrier layer 20 can be wet-applied to the side of the water vapor barrier layer 18 facing away from the paper layer 12 and dried after application. The oxygen barrier layer 20, for example formed from water-insoluble polyurethane, preferably formed from water-soluble PVOH or EVOH, has a coating weight in the range of 1 to 5 g / m² in the ready-to-use dried state. 2 The water vapor barrier layer 18 and the oxygen barrier layer 20 are optional layers, one of which may be present or both of which may be present, but are not required.

[0061] On the side facing away from the paper layer 12, the packaging layer arrangement 10 has a metal-based barrier layer 22, preferably formed by vacuum deposition. The metal-based barrier layer 22 is preferably deposited onto the oxygen barrier layer 20. The metal-based barrier layer 22 has an optical density of between 2.0 and 4.0, preferably between 2.2 and 2.8, particularly preferably 2.5. Its thickness in the illustrated example is approximately 40 nm.

[0062] Since the metal-based barrier layer 22 itself has a very good barrier effect against water vapor migration, the oxygen barrier layer 20 is preferably formed when only one of the barrier layers 18 or 20 is present in the packaging layer arrangement 10. However, if a particularly high barrier effect against water vapor migration is desired, the metal-based barrier layer 22 can be deposited directly onto the water vapor barrier layer 18 without the packaging layer arrangement 10 having the oxygen barrier layer 20.

[0063] In the illustrated embodiment, the oxygen barrier layer 20, which is usually moisture-sensitive due to its material, lies in the direction of a layer sequence LF parallel to the thickness direction of the packaging layer arrangement 10 and to the plane of the drawing in Fig. 1 between the layers 18 and 22 acting as a water vapor barrier. Therefore, the oxygen barrier layer 20 can remain stable for a long time, shielded on both sides from moisture attacking it, and can develop its effect as an oxygen barrier.

[0064] The magnified view shown in Figure 1 shows a metal-based barrier layer 22 in detail. In the preferred embodiment shown, this barrier layer arrangement, as a meta II-based barrier layer arrangement, has a central, thicker metal layer 22a made of metallic aluminum, which is located between two thinner metal oxide layers 22b and 22c made of aluminum oxide. The two metal oxide layers 22b and 22c are also not naturally formed, but were deliberately created by vacuum deposition. Each of the two metal oxide layers 22b and 22c has a thickness of approximately 3 to 4 nm, preferably 3.5 nm, so that the intermediate metal layer 22a has a thickness of approximately 32 to 34 nm, preferably 33 nm.

[0065] In the composite, the metal layer 22a and the metal oxide layers 22b and 22c flanking it on either side exhibit an excellent water vapor barrier effect despite the indicated small thickness. Furthermore, the two metal oxide layers 22b and 22c protect the metal layer 22a located between them from oxidizing attack by the ambient atmosphere.

[0066] Each of the two metal oxide layers 22b and 22c is optional if the metal layer 22a is present, and the metal layer 22a is optional if at least one of the metal oxide layers 22b and 22c is present with sufficient thickness.

[0067] On the side of the metal-based barrier layer 22 facing away from the paper layer 12, a sealable barrier layer 24 made of a sealable thermoplastic polymer mentioned in the introduction to the description is applied. The sealable barrier layer 24 ensures that the packaging layer arrangement 10 is heat-sealable at least on its inner side 10b. The sealable barrier layer 24 can be formed, for example, from polyethylene or a sealable biopolymer. The application weight of the sealable barrier layer 24 made of polyethylene, in particular comprising LDPE or LLDPE, measured in the ready-to-use dried state, is preferably between 2.0 and 10.0 g / m 2 , particularly preferably in the range between 3.0 and 5.0 g / m 2 , particularly preferably between 3.0 and 4.0 g / m 2 . When the sealable barrier layer 24 is formed from a bio-polymer, its application weight, measured in the dry, ready-to-use state, is 5.0 to 30.0 g / m2 , preferably 5.0 to 15.0 g / m 2 , particularly preferably 5.0 to 10.0 g / m 2 Depending on the material selected, the sealable barrier layer 24 can further increase the barrier effect of the packaging layer arrangement 10 against the migration of oxygen and / or water vapor.

[0068] The sealable barrier layer 24 is preferably applied as a dispersion by roller application or by another printing application method over the entire surface, optionally with an intermediate layer of adhesion promoter.

[0069] On the otherwise exposed surface 24b of the sealable barrier layer 24, which faces away from the paper layer 12 and forms an inner surface 10b of the packaging layer arrangement 10 where it is exposed, an additional barrier coating 26 is formed, as shown in a rough schematic diagram, in the form of, for example, two independent and spaced-apart partial coatings 27 and 28. The surfaces 26b of the additional barrier coating 26 facing away from the paper layer 12 also form exposed inner surfaces 10b of the packaging layer arrangement 10.

[0070] The additional barrier coating 26 is applied, preferably as a dispersion by printing, only locally to the sealable barrier layer 24. The material of the additional barrier coating 26 is at least compatible with the material of the sealable barrier layer 24 and is preferably identical thereto in order to achieve a good and permanent bond between the additional barrier coating 26 and the sealable barrier layer 24 when the additional barrier coating 26 is applied directly to the sealable barrier layer 24 without the intermediate arrangement of an adhesion promoter layer.

[0071] The additional barrier coating 26 covers an additional barrier surface area 29 of the surface 24b of the sealable barrier layer 24, while another, larger surface area 31 of the surface 24b of the sealable barrier layer 24 remains exposed.

[0072] The additional barrier coating 26 can participate in sealing connections of the packaging layer arrangement 10 or can act as a mere reinforcement of the sealable barrier layer 24. In Figure 2, identical and functionally identical components and component sections as in Figure 1 are provided with the same reference numerals, but increased by the number 100. The second embodiment shown in Figure 2 is described below only insofar as it differs from the first embodiment of a packaging layer arrangement shown in Figure 1, to whose description express reference is also made for explaining the second embodiment.

[0073] In the second embodiment of Figure 2, the protective layer 116 is optionally formed by the water vapor barrier layer 118. The moisture-sensitive oxygen barrier layer 120 is also located between the water vapor barrier layer 118 and the metal-based barrier layer 122 in the direction of the layer sequence LF in the preferred second embodiment. As a result, the oxygen barrier layer 120 is shielded on both sides against moisture attack, as in the first embodiment.

[0074] However, the protective layer 116 can be designed without a special water vapor barrier effect like the protective layer 16 of the first embodiment.

[0075] Optionally, the packaging layer arrangement 110—or also the packaging layer arrangement 10 of the first embodiment—can comprise a second water vapor barrier layer 125, which is preferably applied directly to the metal-based barrier layer 122 to enhance its barrier effect against water vapor migration. The second water vapor barrier layer 125, which essentially corresponds to the water vapor barrier layer 118 or the water vapor barrier layer 18 of the first embodiment in terms of the type of application, its material, and its application thickness, is thus arranged between the metal-based barrier layer 122 and the sealable barrier layer 124 in this second embodiment.

[0076] In both embodiments, the oxygen barrier layer 20 or 120 is designed to be water-soluble. Due to the shielding on both sides of the oxygen barrier layer 20 or 120 by the water vapor barrier layer 18 or 118 on the one hand and the metal-based barrier layer 22 or 122 on the other, the sensitivity of the oxygen barrier layer to moisture does not impair its stability. In a recycling process, the layers 18, 118, 22, 122 with a barrier effect against water vapor cannot withstand massive attack by liquid water, so that the oxygen barrier layer 20 or 120 can be dissolved during recycling of the packaging layer arrangement 10 or 110. As a result, all layers located on the side of the oxygen barrier layer 20 or 120 facing away from the paper layer 12 or 112 can be easily removed from the paper layer 12 or 112 and removed from the recycling process directed at the paper layer.This significantly increases the recycling success of the packaging layer arrangement 10 or 110.

[0077] Preferably, the proportion of the weight of the paper layer 12 or 112 in the total weight of a partial layer composite 30 or 130, which extends from the outer side 10a or 110a of the packaging layer arrangement 10 or 110 up to and including the metal-based barrier layer 20 or 120, is at least 95%. Particularly preferably, the proportion of the weight of the paper layer 12 or 112 in the total weight of the packaging layer arrangement 10 or 110 is at least 95%. As a result, the partial layer composite 30 or 130, or even the entire packaging layer arrangement 10 or 110, can be classified as a monomaterial and recycled.

[0078] Figure 3 shows, by way of example, a packaging bag 40 which is formed from a packaging layer arrangement 10 or 110 according to the invention.

[0079] The packaging bag 40 shown in Figure 3 is a stand-up bag formed from a single rectangular blank of the packaging layer arrangement 10 or 110.

[0080] The rectangular blank was folded along three folding axes, namely along the folding axes F1 and F3, respectively, with opposing and mutually facing inner sides 10b and 110b of the packaging layer arrangement 10 and 110 used, and along the folding axis F2 with opposing and mutually facing outer sides 10a and 110a of the packaging layer arrangement 10 and 110 used. This results in a so-called "W-fold" of the base region 42 of the packaging 40.

[0081] The parallel longitudinal sides of the package 40 are sealed inside to inside by sealing edges 44 and 46, respectively. Here, the sealable base layer 24 and 124 is sealed against itself. A transverse sealing seam 48 in the head region 50 of the package 40 closes the package 40, so that a packaging space 52 inside the package 40 is completely enclosed by the packaging layer arrangement 10 and 110.

[0082] Due to the W-folding of the blank of the packaging layer arrangement 10 or 110, there is a layer jump at the folding axis F2 and, associated therewith, a thickness jump in the sealing edges 44 and 46: above the folding axis F2, i.e. starting from the folding axis F2 in the direction of the head region 50, only two layers of the packaging layer material 10 or 110 are sealed together, below the folding axis F2, i.e. starting from the folding axis F2 in the direction of the base region 42, four layers of the packaging material 10 or 110 are arranged between the front packaging wall 40a and the opposite rear packaging wall facing away from the viewer of Figure 3. Accordingly, each of the sealing edges 44 and 46 divides at the folding axis F2 in the direction of the base region 42 into two spreadable legs 44a and 44b or 46a and 46b.

[0083] At the location of the fold axis F2, a gusset area 54 is created at the sealing edge 44 in the area of ​​the thickness jump, and a further gusset area 56 is created at the sealing edge 46. In these gusset areas 54 and 56, only the thinly applied sealable barrier layer 24 or 124 with an area-related application weight preferably in the range between 3.0 and 4.0 g / m 2 A permanently tight seal can only be achieved with difficulty.

[0084] In order to achieve a permanently tight and durable seal at this problematic sealing point, an additional barrier coating 26 is applied to the inside of the packaging layer arrangement 10 or 110, which increases the amount of sealable material in the gusset area 54 and 56 and thus enables the gusset areas 54 and 56 to be filled with sealable and barrier-capable material. The additional barrier coating 26 participates in the creation of the sealing connection of the sealing edges 44 and 46 and is at least partially softened or melted. Since the position of the folding axis F2 on the blanks or material cut-outs cut out of the packaging layer arrangement 10 or 110 for producing the packaging 40 is already known due to the existing print image on the packaging layer arrangement 10 or 110, the additional barrier application 26 can be carried out with an extremely small additional quantity of sealable barrier material on the otherwise free surface 24b or124b of the packaging layer arrangement 10 or 110.

[0085] A second embodiment of a package 140, which can be produced with the packaging layer arrangement 10 or 110, is shown in Figure 4. Identical and functionally equivalent components and component sections as in the first embodiment of the package 40 of Figure 3 are designated on the package 140 in the second embodiment of Figure 4 with the same reference numerals, but increased by the number 100. The second embodiment of the package 140 will be described below only insofar as it differs from the first embodiment of the package 40 of Figure 3, to whose description reference is otherwise also made for explaining the embodiment of Figure 4.

[0086] Figure 4 shows a package 140 as is typically used in vertical form, fill, and seal processes for producing the package 140. Packages such as the package 140 are often also referred to as "flow packs." Such manufacturing processes are referred to as "VFFS" processes, and the machines that perform them are accordingly referred to as "VFFS" machines. "VFFS" stands for "Vertical Form, Fill, and Seal." The package 140 is shown only as an example. Packages other than VFFS packages can also benefit from the present invention.

[0087] As will be known to those skilled in the art, VFFS packages such as package 140 are defined longitudinally by two parallel transverse seals 148 and 158, between which extends, on the reverse side of package 140 facing away from the viewer of Figure 4, an inside-to-inside sealed fin seal 160, which joins together opposite ends of a quasi-endless blank of a package layer arrangement 10 or 110.

[0088] During the production of the packaging 140, a quasi-endless belt of the packaging layer arrangement 10 or 110 runs vertically from top to bottom, with the side edges of the packaging layer arrangement 10 or 110 being folded over and placed on top of one another with their respective inner sides to form a tube-like structure with a packaging wall 140a that surrounds a future packaging space 152. The superimposed side edges of the packaging layer arrangement 10 or 110 are joined to form the fin-shaped sealing seam 160 by sliding or rolling sealing tools during the vertical movement.

[0089] The transverse seal seam 148 in the head region 150 of the package 140 is the lower part of a larger transverse seal seam between the packaging space 152 of the package 140 and another package (not shown) adjoining the transverse seal seam 148 at the top in Figure 4. The packages 140, which are initially materially connected, are separated from one another and separated by cutting along their transverse seal seams.

[0090] First, the lower sealing seam 158 of a package 140 is formed. While the packaging layer arrangement 10 or 110 is moved in the vertical direction, the fin sealing seam 160 and, with it, the packaging space 152 enclosed by the packaging layer arrangement 10 or 110 are formed with increasing height above the sealing seam 158. During the formation of the packaging space 152, it is already filled until the upper transverse sealing seam 148 finally completes the formation of the package 140.

[0091] Critical gusset areas 154 and 156 for the formation of the transverse sealing seams are created where the fin sealing seam 160 protrudes from the transverse sealing seam 148 or from the transverse sealing seam 158. Again, to prevent leaks in the sealing seam in the gusset areas 154 and 156, additional barrier applications 126 are provided locally, which provide additional sealable barrier material in the gusset areas 154 and 156, which is actually softened by the sealing process and participates in the resulting sealing connection.

[0092] Longitudinal edge regions 162 and 164 of the packaging 140 run between the transverse end regions of the transverse sealing seams 148 and 158, in which the packaging 140 or its packaging wall 140a is more strongly curved than in a front region 166 and in a rear region 168 between the longitudinal edge regions 162 and 164. Due to this greater curvature, the longitudinal edge regions 162 and 164 are at risk of greater buckling and folding stress on the packaging 140 than other packaging regions. In the longitudinal edge regions 162 and 164 which are subject to greater mechanical stress, there is a greater risk of the barrier integrity of the packaging layer arrangement 10 or 110 being compromised due to more frequent kinking and folding than in other regions of the packaging 140. Therefore, in order to mechanically reinforce these more heavily stressed longitudinal edge regions 162 and 164, on the surface 24b or 124b of the sealable barrier layer 24 or 124 of the packaging layer arrangement 10 or 110 facing the packaging space 152,110 additional barrier applications 126' and 126" are provided, which simply reinforce the material thickness of the packaging layer arrangement 10 or 110, respectively, without themselves being involved in a sealing process. The additional barrier applications 126' and 126" are therefore not softened or melted during the formation of the packaging 140, in contrast to the additional barrier applications 126.

[0093] This means that the 140 packaging can achieve a long shelf life without affecting its barrier properties, even when exposed to high mechanical stress on its more heavily deformed areas.

Claims

Claims 1. Packaging layer arrangement (10; 110) for producing a packaging container (40; 140), wherein the packaging layer arrangement (10; 110) comprises: a paper layer (12; 112) as a carrier layer, a metal-based barrier layer (22; 122) carried by the paper layer (12; 112), and a sealable barrier layer (24; 124) arranged on the side of the metal-based barrier layer (22; 122) facing away from the paper layer (12; 112), characterized in that a sealable additional barrier coating (26; 126, 126', 126") is arranged on the sealable barrier layer (24; 124) only locally in at least one additional barrier surface area (29; 129), wherein the additional barrier surface area (29; 129) is smaller than the extension area of ​​the sealable barrier layer (24; 124), so that at least one further surface area (31; 131) of the sealable barrier layer (24; 124) is free of the additional barrier application (26; 126, 126', 126").

2. Packaging layer arrangement (10; 110) according to claim 1, characterized in that the sealable barrier layer (24; 124) is exposed in the at least one further surface area (31; 131).

3. Packaging layer arrangement (10; 110) according to claim 1 or 2, characterized in that the sealable barrier layer (24; 124) is applied as a continuous, uninterrupted surface.

4. Packaging layer arrangement (10; 110) according to one of the preceding claims, characterized in that the sealable barrier layer (24; 124) is applied as a dispersion.

5. Packaging layer arrangement (10; 110) according to one of the preceding claims, characterized in that the size of the additional barrier surface area (29; 129) is 5% to 25% of the size of the extension surface of the sealable barrier layer (24; 124).

6. Packaging layer arrangement (10; 110) according to one of the preceding claims, characterized in that the additional barrier coating (26; 126, 126', 126") is applied as a dispersion.

7. Packaging layer arrangement (10; 110) according to one of the preceding claims, characterized in that the additional barrier coating (26; 126, 126', 126") has a surface-related coating weight in the range of 2 to 5 g / m 2 has.

8. Packaging layer arrangement (10; 110) according to one of the preceding claims, characterized in that the area-related application weight of the additional barrier layer (26; 126, 126', 126") on the one hand and of the sealable barrier layer (24; 124) on the other hand differs by not more than 1 g / m 2 differentiate.

9. Packaging layer arrangement (10; 110) according to one of the preceding claims, characterized in that the sealable barrier layer (24; 124) is applied to the metal-based barrier layer (22; 122) directly or with the interposition of only one adhesion promoter layer.

10. Packaging layer arrangement (10; 110) according to one of the preceding claims, characterized in that a primer coating (18, 20; 120) with a barrier effect against migration of oxygen or water vapor is applied between the metal-based barrier layer (22; 122) and the paper layer (12; 112).

11. Packaging (40; 140) comprising a packaging wall (40a; 140a) and a packaging space (52; 152) surrounded by the packaging wall (40a; 140a), characterized in that the packaging wall (40a; 140a) is formed at least partially from a packaging layer arrangement (10; 110) according to one of the preceding claims, wherein the packaging (40; 140) has at least one sealing region (44, 46, 48; 148, 158, 160) in which a section of the sealable barrier layer (24; 124) of the packaging layer arrangement (10; 110) is connected to another section of the sealable barrier layer (24; 124) or to a section of a compatible other layer to form a sealing connection.

12. Packaging (40; 140) according to claim 11, characterized in that the packaging (40) has at least one sealing region (44, 46) which has a sudden change in its thickness along its course and / or a gusset region (54, 56; 154, 156), wherein in the region of the sudden change in thickness and / or in the gusset region (54, 56; 154, 156) a section of the additional barrier coating (26) is part of the sealing connection of the sealing region (44, 46).

13. Packaging (40) according to claim 12, characterized in that a sudden change in thickness of the sealing region (44, 46) is brought about by the sealable barrier layer (24) being folded back on itself to form a layer jump along the sealing region (44, 46), wherein in the region of the layer jump a section of the additional barrier coating (26) is part of the sealing connection of the sealing area (44, 46).

14. Packaging (140) according to one of claims 11 to 13, characterized in that the packaging wall (140a) has an unsealed section which delimits the packaging space (152) and is reinforced by the additional barrier coating (126', 126"), in which section the additional barrier coating (126'; 126"") lies unsealed opposite the packaging space (150).

15. Packaging (140) according to claim 14, characterized in that the reinforced packaging wall section (162, 164) carrying the unsealed additional barrier coating (126'; 126") is more curved than an unreinforced packaging wall section (166, 168) adjacent to the reinforced packaging wall section (162, 164).

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