IL296475A

IL296475A - Packaging foil

Info

Publication number: IL296475A
Application number: IL296475A
Authority: IL
Original assignee: Constantia Teich Gmbh
Priority date: 2020-03-18
Filing date: 2021-03-15
Publication date: 2022-11-01
Also published as: WO2021185731A1; PL4121284T3; AT522883A4; AT522883B1; EP4121284A1; ES2956564T3; EP4121284B1

Description

PACKAGING FOIL The present disclosure relates to packaging foils having a first aluminum foil, a second aluminum foil, and a bonding layer which connects the first aluminum foil to the second aluminum foil. The present disclosure further relates to methods for producing a packaging foil.

The packaging of three-dimensional and, optionally, figure-shaped food products, such as chocolate or pralines in the form of Easter bunnies, Santas, or the like, requires thin packaging foils which lie well and permanently against the outer contour of the product and remain in this shape permanently by themselves. Packaging foils with these properties are also advantageous for packaging products with "conventional" shapes, such as chocolate bars, confectionery, or candies. This requires a packaging foil which has substantially no elastic restoring behavior when folded (this is also referred to as "deadfold behavior"). Machine processability is also an important criterion in the production of such packaging foils.

In addition, consumers expect a haptic sensory impression which is described as "velvety," for example, when gripping and unwrapping the packaging. This expectation is influenced by the currently used thin foils, in which an outer layer of a thin, printed paper and an inner layer of aluminum are laminated to one another (or vice versa, in which case the paper forms the inner layer and the aluminum the optionally printed outer layer). Such foil composites have been used for a long time.

Due to increased demands on the recyclability of packaging materials, composites with different materials which are to be disposed in different ways (i.e., aluminum and paper in this case) are increasingly regarded as problematic. It is therefore an object of the present disclosure to provide alternatives to the previously used packaging materials which have improved recyclability.

However, in order to be able to replace existing and long-established packaging materials, it is necessary for newly-developed materials also to achieve the advantageous properties of the old, established products. In practice, however, numerous hurdles are to be overcome, since alternative, easily recyclable products by themselves do not have the desired properties, or have them only to a limited extent. 1 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] For example, the use of a substantially mono-material aluminum foil would be advantageous with regard to recyclability, but it has been found that conventional aluminum foils do not have the required processability for this specific purpose and, for example, tear too easily. Also, the haptic properties desired by the consumers cannot be achieved therewith. With known packaging materials, it has hitherto not been possible to achieve and optimize the different requirements (in particular, recyclability, machine processability, pliancy, deadfold behavior, haptics) at the same time.

In a first aspect, the present disclosure relates to a packaging foil of the type mentioned at the outset, wherein the first and the second aluminum foils each have a strength state, wherein the strength states are selected independently of one another from a work-hardened and re annealed and/or a soft-annealed state, wherein, by selection of the degree of hardness, achieved by re-annealing, of the first and of the second aluminum foils, a desired tensile force (Fmax) of the packaging foil is set to a value of at least 20 N in the longitudinal and transverse direction, a desired elongation at break (A100) of the packaging foil is set to a value of at least 3% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value of less than 70 mN in the longitudinal and transverse directions, wherein the tensile force and the bending stiffness of the packaging foil decrease with decreasing degree of hardness of each aluminum foil, and wherein the elongation at break increases with decreasing degree of hardness of each aluminum foil.

Advantageously, the desired tensile force (Fmax) can be at least 40 N in the longitudinal and transverse direction. This allows the packaging stations to be operated at a higher speed and cycle rate.

The present inventors have found that a combination of two different aluminum foils makes it possible to set the characteristics of the packaging foil such that a substantially "mono material" aluminum foil is obtained (only with a low adhesive content), which optimally corresponds to the complex requirements. To this end, a first, partially re-annealed or soft- annealed aluminum foil is combined with a second aluminum foil, wherein the second aluminum foil was also at least partially re-annealed from the work-hardened state. By the degree of recrystallization of the second aluminum foil caused by the re-annealing, the properties of the packaging foil obtained can be set such that they correspond to the complex requirements. 2 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] In tests carried out by the present inventors, it was found that, although a combination of two "soft" (i.e., fully soft-annealed) aluminum foils can achieve good ductility, the tensile strength and thus the required tensile force is too low, or the foil thickness must be selected to be excessively high in order to achieve the required tensile force, as a result of which the bending stiffness is in turn too high. On the other hand, if a hard (i.e., fully through-hardened) aluminum foil is combined with a soft aluminum foil, a very good tensile force was achieved, but the ductility was too low and the bending stiffness too high.

The exact values for the thicknesses and the states of the aluminum foils are dependent upon the aluminum alloy(s) used and the specific application. However, the exact degree of recrystallization of the first and second aluminum foils can be found out by a person skilled in the art with knowledge of the teachings disclosed herein, using routine tests and experiments for given aluminum alloys.

The states disclosed herein, namely, - O ... soft-annealed - H ... work-hardened ○ H1x ... only work-hardened ○ H2x ... work-hardened and re-annealed ▪ H22 ... work-hardened and re-annealed – 1/4 hard ▪ H24 ... work-hardened and re-annealed – 1/2 hard ▪ H26 ... work-hardened and re-annealed – 3/4 hard ▪ H28 ... work-hardened and re-annealed – 4/4 hard refer to the DIN EN 515 standard in the version of December 1993, "Aluminum und Aluminiumlegierungen – Halbzeug – Bezeichnung der Werkstoffzustände." For use as a packaging foil, it is important that a thermal treatment be carried out after the foil rolling (this corresponds to an H16-H19 state). In addition to the desired setting of the mechanical properties of the foil, the thermal treatment brings about a degreasing of the surface, wherein residues of coolants and lubricants are removed.

The values for the tensile force Fmax, the tensile strength (Rm), and the elongation at break (A100) are determined by tensile test according to the DIN 50154:2019-09 standard, wherein 3 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] the initial measurement length (L0) of the test strips (initial width b0 = 15 mm) is 100 mm. Unless expressly stated otherwise, the values of the tensile force (Fmax) indicated in this disclosure refer to the absolute tensile strength of the 15 mm-wide test strip in N. The value of the tensile force (Fmax) is also referred to as the maximum force. A conversion between the value for the tensile strength (Rm in N/mm2 or MPa) and the area tensile force (Fmax in N) can be carried out using the width and the thickness of the tested foil.

The bending stiffness (B) of the packaging foil is determined essentially according to the DIN 53121:2014-08 standard, using either the two-point method described therein or the four-point method described therein. The bending stiffness B can be indicated either equivalently as bending stiffness BS per unit width in Nm (or mNm) or as measured bending stiffness (or bending force) BF in N (or mN).

The procedure for determining the bending stiffness of the composite material 1 is described using the example of a two-point measurement. A sample of the composite material 3 clamped on one side is loaded at a certain distance l bya rotatable clamp with a bending force F acting perpendicularly on the sample surface until a predetermined bending angle α of the sample is reached. The deformation rate until the bending angle α is reached is kept constant. The maximum resistance which the sample offers to this bending is measured as bending stiffness.

In essence ,the absolute bending stiffness or bending force BF necessary to bend the sample by the bending angle α is measured. It is then possible to convert from this to the bending 60 Bl2 F stiffness Bs per unit width using the relationship Bs = k ab For example, a bending angle α of 30°, a sample width b of 15 mm, and a distance l from the clamp to the force application point of 1 mm are defined as measurement conditions. All the values listed herein relate to these measurement conditions, wherein the bending force BF is given in each case in mN.

Measuring instruments for determining the bending stiffness B are commercially available -for example, from Lorentzen & Wettre.

Advantageously, the first aluminum foil and the second aluminum foil can have a different strength state. As a result, the parameters can be regulated more finely, and the finding of 4 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] suitable packaging foils by experiments and tests is facilitated by the reduction of the parameters to be varied.

In a preferred embodiment, the first aluminum foil can have a soft-annealed state (O), wherein the second aluminum foil has a work-hardened and re-annealed state, wherein, by selection of the degree of hardness, achieved by re-annealing, of the second aluminum foil, a desired tensile force (Fmax) of the packaging foil is set to a value of at least 20 N in the longitudinal and transverse direction, a desired elongation at break (A100) of the packaging foil is set to a value of at least 3% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value of less than 70 mN in the longitudinal and transverse direction. In practice, this makes it easier to find suitable material combinations, and the proportion of the soft aluminum foil ensures very good haptic properties.

In order to obtain a packaging foil with even higher quality, a desired tensile force (Fmax) of the packaging foil can be set to a value of at least 20 N in the longitudinal and transverse direction, a desired elongation at break (A100) of the packaging foil can be set to a value of at least 4% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil can be set to a value of below 55 mN in the longitudinal and transverse direction.

In an advantageous embodiment, the total thickness of the packaging foil can be between 12 µm and 30 µm, and preferably between 14 and 20 µm. The packaging foil allows a material saving minimization of the thickness, wherein the use of foils with a thickness above the achievable minimum can also be advantageous, for example, from a quality standpoint.

Advantageously, the states of the first and/or second aluminum foils can be selected independently of one another from soft-annealed – O, work-hardened and re-annealed – 1/4 hard (H22), work-hardened and re-annealed – 1/2 hard (H24), work-hardened and re-annealed – 3/4 hard (H26), and work-hardened and re-annealed – 4/4 hard (H28). The listed designations refer to the aforementioned DIN EN 515:1993-12 standard.

In an advantageous embodiment, the bonding layer can have an adhesive, which is selected from a pressure-sensitiv eadhesive, a laminating wax, a dry laminating adhesive, an extrusion lamination, and a mixed adhesive system.

DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] Advantageously, the proportion of the bonding layer in the packaging foil can be functionally minimized. This is generally the case when the bonding layer is present in a thickness of between 1 and 7 g/m2. In this context, "functionally minimized" means that the proportion is minimized by means of experiments and tests, as far as the functionality allows.

In a further aspect, the present disclosure relates to a method for producing a packaging foil, wherein a first aluminum foil with a second aluminum foil are connected to one another by means of a bonding layer, wherein in each case a strength state is selected for the first and the second aluminum foils, wherein the strength states are selected independently of one another from a work-hardened and re-annealed and a soft-annealed state, wherein, by selection of the degree of hardness, achieved by re-annealing, of the first and of the second aluminum foils, a desired tensile force (Fmax) of the packaging foil is set to a value of at least N in the longitudinal and transverse direction, a desired elongation at break (A100) of the packaging foil is set to a value of at least 3% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value below 70 mN in the longitudinal and transverse direction, wherein the tensile force (Fmax) and the bending stiffness of the packaging foil decrease with decreasing degree of hardness of each aluminum foil, and wherein the elongation at break increases with decreasing degree of hardness of each aluminum foil.

Advantageously, aluminum foils with a different strength state can be selected as the first aluminum foil and as the second aluminum foil.

In a further advantageous embodiment, the first aluminum foil can have a soft-annealed state (O), wherein the second aluminum foil has a work-hardened and re-annealed state, wherein, by selection of the degree of hardness, achieved by re-annealing, of the second aluminum foil, a tensile force (Fmax) of the packaging foil is set to a value of at least 20 N in the longitudinal and transverse direction, a desired elongation at break (A100) of the packaging foil is set to a value of at least 3% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value of less than 70 mN in the longitudinal and transverse direction, wherein the tensile force (Fmax) and the bending stiffness of the packaging foil decrease with decreasing degree of hardness of the second aluminum foil, and wherein the elongation at break increases with decreasing degree of hardness of the second aluminum foil. 6 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] Advantageously, a desired tensile force (Fmax) of the packaging foil can be set to a value of at least 20 N in the longitudinal and transverse direction, a desired elongation at break (A100) of the packaging foil can be set to a value of at least 4% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil can be set to a value of below 55 mN in the longitudinal and transverse direction.

Advantageously, the total thickness of the packaging foil can be between 12 µm and 30 µm, and preferably between 14 and 20 µm.

In an advantageous embodiment, the states of the first and/or second aluminum foils can be selected independently of one another from soft-annealed – O, work-hardened and re annealed – 1/4 hard (H22), work-hardened and re-annealed – 1/2 hard (H24), work-hardened and re-annealed – 3/4 hard (H26), and work-hardened and re-annealed – 4/4 hard (H28).

In a further advantageous embodiment, an adhesive which is selected from a pressure sensitive adhesive, a laminating wax, a dry laminating adhesive, an extrusion lamination, and a mixed adhesive system can be selected as the bonding layer.

Advantageously, the proportion of the bonding layer in the packaging foil can be functionally minimized in particular to a value between 1 and 7 g/m2.

The present invention is described in greater detail below with reference to Figure 1, which shows an advantageous embodiment of the invention by way of example, schematically and in a non-limiting manner. In the drawings: Fig. 1 shows a schematic diagram of the layer structure of the packaging foil.

The layer structure of a packaging foil 3 shown schematically in figure 1 comprises a first aluminum foil 1, a second aluminum foil 2, and a bonding layer 4 which is arranged between the first aluminum foil 1 and the second aluminum foil 2 and connects the two aluminum foils 1 and 2 to one another. 7 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] The bonding layer 4 consists of a laminating adhesive selected from a pressure-sensitive adhesive, a laminating wax, a dry laminating adhesive, an extrusion lamination, and a mixed adhesive system. Preference is given to mixed adhesive systems, pressure-sensitive adhesives, and laminating waxes, since dry laminating adhesives between two barrier layers can be problematic with regard to gas release and bubble formation.

Laminating waxes that can be used by way of example include, inter alia, the products sold by the company, Paramelt BV, the Netherlands, under the trade names, Paraflex Nowax™ L201 or Paraflex™ L 7075.

Mixed adhesive systems can, for example, use a mixture of a first, curing adhesive and a second, non-curing adhesive, both of which are preferably suitable for food. The laminating agent obtained therewith is applied with layer thicknesses in the range of 0.5 g/m2 to 8 g/m2 for applications in the packaging industry.

Adhesives based upon thermoplastic elastomers, e.g., polyolefin-based adhesives, adhesives in the form of styrene block copolymer or in the form of ethylene vinyl acetate (EVA) copolymer, can be used as the first, curing adhesive. Examples of such adhesives are adhesives containing styrene butadiene, or ethylene vinyl acetate (EVA) copolymer with a vinyl acetate content up to 28%. Thermoplastics are likewise suitable, e.g., polyacrylate-containing adhesives or ethylene copolymerizates such as ethylene-acrylic acid (EAA). The first adhesive is generally present in liquid form, e.g., as a solution, emulsion, or dispersion of the first adhesive in a liquid phase, e.g., water or a suitable liquid solvent. The first adhesive can be a one-component, but can also be a multicomponent adhesive.

Adhesives based upon thermoplastic elastomers, e.g., polyolefin-based adhesives, adhesives in the form of styrene block copolymer or in the form of ethylene vinyl acetate (EVA) copolymer, can be used as the second non-curing adhesive. Examples of such adhesives are adhesives containing styrene butadiene, or ethylene vinyl acetate (EVA) copolymer with a vinyl acetate content up to 28%. A pressure-sensitive adhesive can in particular be used as the second, non-curing adhesive. Common pressure-sensitive adhesives are low-molecular-weight, polyacrylate-containing adhesives or styrene-butadiene-containing adhesive. The second adhesive is also generally present in liquid form, e.g., as a solution, emulsion, or dispersion of the second adhesive in a liquid phase, e.g., water or a suitable liquid solvent. 8 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] Styrene-butadiene-containing adhesive is understood in particular to mean an adhesive which contains 60% to 80% (by weight) styrene-butadiene. Polyacrylate-containing adhesive is understood to mean an adhesive which contains 50% to 90% (by weight) polyacrylate. These proportions are not in relation to the dispersion, but in relation to the solids content of the adhesives.

The mixture of the two adhesives is therefore likewise present in liquid form, wherein the liquid phases of the two adhesives must be compatible. Preferably, the same liquid phase, e.g., water or the same solvent, is used for both adhesives. In addition, water can be added to the mixture of the two adhesives for processing. Likewise, suitable additives, e.g., stabilizers (max. 2%), fillers (max. 10%), and/or defoamers (max. 1%), can also be added to the mixture in small amounts – typically, in total, at most 10% in relation to the weight of the liquid mixture.

The mixing ratio M of the first, curing adhesive and the second, non-curing adhesive in the laminating agent can vary over a very wide range, depending upon the application and material selection. Mixing ratios M between the two adhesives in the range of 10% first, curing adhesive to 90% second, non-curing adhesive through 90% first, curing adhesive to 10% second, non curing adhesive are possible. The mixing ratio M relates to the solids content of the adhesives.

For a specific embodiment, a commercially available first, curing adhesive in the form of a styrene-butadiene-containing adhesive with the product name LANDOCOL 7170 from Svenska Lim AB was mixed with a commercially available second, non-curing adhesive in the form of a polyacrylate-containing adhesive with the product name AQUENCE ENV 1626-24 from Henkel with a mixing ratio of 50/30 (based upon the adhesive masses) as an aqueous solution. Bonding layers 4 with a material thickness of approximately 1.8 g/m2 were produced with this mixed adhesive.

In a further embodiment, the laminating adhesives described above as the first adhesive and second adhesive can also be used unmixed.

The adhesive properties of the adhesive can be improved in a manner known per se by a surface coating, for example, with an undercoat or primer. Such additional layers are in each case regarded as part of the bonding layer 4, in connection with the present disclosure. 9 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] Any aluminum alloy suitable for foil production can be used as the starting material for the production of the first and the second aluminum foils, wherein iron-based alloys, in particular, alloys of series 8000 according to DIN EN 573-3:2019-10, are preferred. For example, one or both aluminum foils can consist of an aluminum alloy selected from EN AW-8021B (EN AW-Al Fe1.5) or EN AW-8079 (EN AW-Al Fe1Si) – designations in each case in accordance with DIN EN 573-3:2019-10. The present disclosure is in no way limited to these exemplary alloys, but includes all alloys which for technical reasons are suitable for the purpose and are known to the person skilled in the art.

Before lamination, the first and the second aluminum foils are each rolled to a desired thickness by known rolling methods (or acquired in a desired rolled thickness), wherein the thickness can in particular be between 5.5 µm and 20 µm. Typical values for the thickness of the aluminum foils are, for example, 5.5 µm, 6 µm, 7 µm, 8 µm, 9 µm, 10 µm, 12 µm, 15 µm, or 20 µm.

The total thickness of the composite foil 3 results from the sum of the thicknesses of the first aluminum foil 1, the second aluminum foil 2, and the bonding layer 4. The total thickness of the composite foil 3 can, for example, be between 12 µm and 30 µm, and preferably between 14 and 20 µm.

After rolling to the desired thickness, the aluminum foils are in a fully-hard state (i.e., state H1x – only work-hardened, without additional thermal treatment). This state is usually also referred to as "hard" for simplicity. Although hard aluminum foils achieve a high tensile strength, they have very low ductility. The elongation at break is usually only 1-2%. Such a value is problematic for use as packaging material due to poor machine processability. The present inventors have found that composite foils having multiple aluminum foils, only one of which is hard, have a very low elongation at break (approximately between 1-2%).

Therefore, both aluminum foils are subjected to a heat treatment prior to lamination. Preferably, the first aluminum foil 1 and the second aluminum foil 2 are each heat-treated in different ways.

The optimal heat treatment of an aluminum foil is, on the one hand, dependent upon the thickness of said aluminum foil, but also upon the thickness and the state of the other aluminum foil and upon the total thickness of the packaging foil. The optimal setting or selection of the DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] thicknesses and heat treatments therefore requires experiments and tests to be performed by a person skilled in the art capable of performing them, with knowledge of the teachings disclosed herein.

The aim is to find a combination of a first aluminum foil 1 and a second aluminum foil 2 which, in the case of a given bonding layer 4, comply with the following criteria: 1. The tensile force Fmax of a 15 mm-wide test strip (according to DIN 50154:2019-09) is at least 20 N, and preferably at least 40 N, in order to improve the machine processability. 2. The elongation at break A100 of a 15 mm-wide test strip with a clamping length of 100 mm (according to DIN 50154:2019-09) is at least 3%, and preferably at least 4%. 3. The bending stiffness BF, measured according to the method described herein in the introduction, is at most 70 mN, and preferably at most 55 mN.

In order to find a suitable composite foil which complies with all of these criteria, it is possible, for example, to produce corresponding test series for the selected material thickness, which differ in each case in terms of the states caused by the heat treatment. If several suitable candidates are found in this way, a further selection can be made by a manually performed test of the felt haptics.

In order to reduce the number of material patterns to be produced, the following advantageous method can be carried out: 1. Selecting an alloy and a thickness of the first aluminum foil 1. 2. Selecting an alloy and a thickness of the second aluminum foil 2. 3. Selecting a suitable laminating adhesive system. 4. Heat-treating the first aluminum foil 1 to a soft-annealed state O.

. Dividing the second aluminum foil 2 into multiple patterns and soft-annealing the patterns to different recrystallization degrees or states (e.g., soft-annealed – O, work-hardened and re annealed – 1/4 hard (H22), work-hardened and re-annealed – 1/2 hard (H24), work-hardened and re-annealed – 3/4 hard (H26), work-hardened and re-annealed – 4/4 hard (H28)). 6. Producing multiple patterns of the composite foil with always the first aluminum foil 1 and in each case a different pattern of the second aluminum foil 2. 7. Testing the properties of the different patterns (tensile strength Rm, tensile force Fmax, elongation at break A100, and bending stiffness BF). 8. Evaluating the patterns in terms of the properties and selecting suitable candidates. 11 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0] Should the result of the test series not be satisfactory for whatever reason, the test series can be repeated with another combination of layer thicknesses, with another combination of alloys, and/or with another adhesive system.

The inventors have found that the measured values of packaging foils produced in the laboratory with a first aluminum foil, a "manually" applied bonding layer, and a second aluminum foil ("laboratory laminations") surprisingly differ from packaging foils which are identical in structure and which were manufactured in production (production laminations). For example, the values of the elongation of the laboratory laminations were consistently greater by approximately 20-25% than the values which were then finally achieved with the production laminations. The values of the bending stiffness were approximately 25-30% higher in the production laminations than the values of the corresponding laboratory laminations.

Before implementing the complex tests in production, it must thus be taken into account in the selection of preferred material combinations that packaging foils are less ductile and more rigid in series production than corresponding laboratory laminates. It is assumed that these different properties are brought about in particular due to the mounting of the production laminations on large rollers and the resulting pressure. In any case, the person skilled in the art with knowledge of the teachings disclosed herein is capable of taking this finding into account in the selection of suitable composite foils. The values disclosed herein relate in each case to production laminations.

Claims

1. Packaging foil having a first aluminum foil, a second aluminum foil, and a bonding layer which connects the first aluminum foil to the second aluminum foil, characterized in that the 5 first and the second aluminum foil each have a strength state, wherein the strength states are each selected independently of one another from a work-hardened and re-annealed and/or a soft-annealed state, wherein, by selection of the degree of hardness, achieved by re annealing, of the first and of the second aluminum foil, a desired tensile force (Fmax) of the packaging foil is set to a value of at least 20 N in the longitudinal and transverse direction, a 10 desired elongation at break (A100) of the packaging foil is set to a value of at least 3% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value below 70 mN in the longitudinal and transverse direction, wherein the tensile force and the bending stiffness of the packaging foil decrease with decreasing degree of hardness of each aluminum foil, and wherein the elongation at break increases with decreasing 15 degree of hardness of each aluminum foil.

2. Packaging foil according to claim 1, characterized in that the first aluminum foil and the second aluminum foil have a different strength state. 20

3. Packaging foil according to claim 1 or 2, characterized in that the first aluminum foil has a soft-annealed state (O), wherein the second aluminum foil has a work-hardened and re annealed state, wherein, by selection of the degree of hardness, achieved by re-annealing, of the second aluminum foil, a desired tensile force (Fmax) of the packaging foil is set to a value of at least 20 N in the longitudinal and transverse direction, a desired elongation at break (A100) 25 of the packaging foil is set to a value of at least 3% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value of less than 70 mN in the longitudinal and transverse direction.

4. Packaging foil according to one of claims 1 to 3, characterized in that a desired tensile 30 force (Fmax) of the packaging foil is set to a value of at least 20 N in the longitudinal and transverse direction, a desired elongation at break (A100) of the packaging foil is set to a value of at least 4% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value below 55 mN in the longitudinal and transverse direction. 13 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0]

5. Packaging foil according to one of claims 1 to 4, characterized in that the total thickness of the packaging foil is between 12 µm and 30 µm, and preferably between 14 and 20 µm.

6. Packaging foil according to one of claims 1 to 5, characterized in that the states of the 5 first and/or second aluminum foils are selected independently of one another from soft- annealed – O, work-hardened and re-annealed – 1/4 hard (H22), work-hardened and re annealed – 1/2 hard (H24), work-hardened and re-annealed – 3/4 hard (H26), and work- hardened and re-annealed – 4/4 hard (H28). 10

7. Packaging foil according to one of claims 1 to 6, characterized in that the bonding layer has an adhesive which is selected from a pressure-sensitive adhesive, a laminating wax, a dry laminating adhesive, an extrusion lamination, and a mixed adhesive system.

8. Packaging foil according to one of claims 1 to 7, characterized in that the proportion of 15 the bonding layer in the packaging foil is functionally minimized and in particular is between 1 and 7 g/m2.

9. Method for producing a packaging foil, wherein a first aluminum foil and a second aluminum foil are connected to one another by means of a bonding layer, characterized in 20 that a strength state is selected in each case for the first and the second aluminum foil, wherein the strength states are selected independently of one another from a work-hardened and re annealed and a soft-annealed state, wherein, by selection of the degree of hardness, achieved by re-annealing, of the first and of the second aluminum foil, a desired tensile force (Fmax) of the packaging foil is set to a value of at least 20 N in the longitudinal and transverse direction, 25 a desired elongation at break (A100) of the packaging foil is set to a value of at least 3% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value of less than 70 mN in the longitudinal and transverse direction, wherein the tensile force and the bending stiffness of the packaging foil decrease with decreasing degree of hardness of each aluminum foil, and wherein the elongation at break increases with 30 decreasing degree of hardness of each aluminum foil.

10. Method according to claim 9, characterized in that aluminum foils with a different strength state are selected as the first aluminum foil and as the second aluminum foil. 14 DynamicPDF for .NET v8.0.0.40 (Build 29393)Evaluating unlicensed DynamicPDF feature. Click here for details. [4:0:v8.0]

11. Method according to claim 9 or 10, characterized in that the first aluminum foil has a soft-annealed state (O), wherein the second aluminum foil has a work-hardened and re annealed state, wherein, by selection of the degree of hardness, achieved by re-annealing, of the second aluminum foil, a desired tensile force (Fmax) of the packaging foil is set to a value 5 of at least 20 N in the longitudinal and transverse direction, a desired elongation at break (A100) of the packaging foil is set to a value of at least 3% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value below 70 mN in the longitudinal and transverse direction, wherein the tensile strength and the bending stiffness of the packaging foil decrease with decreasing degree of hardness of the second aluminum foil, 10 and wherein the elongation at break increases with decreasing degree of hardness of the second aluminum foil.

12. Method according to one of claims 9 to 11, characterized in that a desired tensile strength (Rm) of the packaging foil is set to a value of at least 20 N in the longitudinal and 15 transverse direction, a desired elongation at break (A100) of the packaging foil is set to a value of at least 4% in the longitudinal and transverse direction, and a desired bending stiffness (BF) of the packaging foil is set to a value below 55 mN in the longitudinal and transverse direction.

13. Method according to one of claims 9 to 12, characterized in that the total thickness of 20 the packaging foil is between 12 µm and 30 µm, and preferably between 14 and 20 µm.

14. Method according to one of claims 9 to 13, characterized in that the states of the first and/or second aluminum foil are selected independently of one another from soft-annealed – O, work-hardened and re-annealed – 1/4 hard (H22), work-hardened and re-annealed – 1/2 25 hard (H24), work-hardened and re-annealed – 3/4 hard (H26), and work-hardened and re annealed – 4/4 hard (H28).

15. Method according to one of claims 9 to 14, characterized in that an adhesive selected from a pressure-sensitive adhesive, a laminating wax, a dry laminating adhesive, an extrusion 30 lamination, and a mixed adhesive system is selected as the bonding layer.

16. Method according to one of claims 9 to 15, characterized in that the proportion of the bonding layer in the packaging foil is functionally minimized in particular to a value between 1 and 7 g/m2.