Recyclable paper packaging laminate with thin barrier film and good tear properties

Description

[0001] The present invention relates to a packaging laminate consisting of a carrier layer and a barrier film, wherein the carrier layer consists of paper with a basis weight of 40 to 120 g / m², wherein a barrier film is connected to the carrier layer via a bonding layer, wherein a plastic film stretched in at least one stretching direction is provided as the barrier film.

[0002] Plastic packaging laminates are now used for a wide variety of packaging in different sectors. Nevertheless, the long-lasting nature of most materials causes fundamental environmental problems. This fact is recognized by both legislators and consumers. Legislative initiatives exist at the national and supranational levels. In Austria, the amendment to the Waste Management Act, effective January 1, 2020, serves as an example. This amendment banned so-called "plastic bags" from retail outlets.

[0003] However, due to increased environmental awareness, the average consumer is also reluctant to purchase packaging materials made exclusively from non-recyclable materials. Accordingly, there is a trend towards the production of alternative packaging materials, such as those based on bioplastics like polyhydroxybutyral or polylactides. Paper-based packaging, for example for food deliveries, chips, or even for sealing strips on various types of packaging, is also becoming increasingly popular.

[0004] In general, all packaging must meet certain minimum standards to guarantee the freshness and shelf life of the packaged goods. With most conventional plastics, but also with metallic packaging, such as aluminum beverage capsules, barrier properties were usually ensured by the materials' impermeability to aromas, gases, and liquids. Newer, environmentally friendly materials often have poorer barrier properties and therefore frequently need to be modified or coated to meet the barrier requirements for packaging materials.

[0005] Specific transfer rates for characteristic substances are often given as indicators of barrier properties. The oxygen transfer rate (OTR) is particularly relevant due to the oxidation of food, as is the water vapor transfer rate (WVTR) with regard to microbial contamination. Fat transfer rates and aroma barrier properties are also frequently important.

[0006] Therefore, the fundamental goal is to provide environmentally friendly packaging materials that meet the necessary barrier properties and are preferably also recyclable.

[0007] One possible method for assessing the recyclability of paper-based packaging laminates is the so-called PTS-RH 021 / 97 method. Particular attention should be paid to the fiberization behavior and the formation of stickiness. Stickiness, in this context, refers to the deposition of adhesive contaminants during recycling. During paper production, adhesive components can form during sheet formation and subsequent drying due to heat-seal varnishes, adhesives, etc., and these are undesirable. To determine the fiberization behavior, the paper-based packaging is fiberized using a laboratory pulper. After this fiberization process, the material is fractionated. Individual fibers and fillers can be separated using a slotted or perforated plate. The remaining coarse reject, such as plastic parts and similar materials, is considered a non-paper component and is therefore not recyclable.If this proportion is less than 20%, it is referred to as a recyclable, paper-based packaging laminate.

[0008] EP 1 083 043 B1 discloses a packaging laminate for ice cream packaging, such as cone-shaped bags, comprising a layer of polypropylene (PP), polyethylene (PE), or polyamide (PA) with layer thicknesses of 6-25 µm and parchment, glassine, or parchment substitute paper with basis weights of 60-110 g / m². A key requirement for this packaging is that it must be grease- and moisture-resistant. Recyclability is not addressed in the disclosure.

[0009] EP 3 784 486 A1 discloses a packaging laminate made of a glassine / PET composite with PET layer thicknesses of 5-70 µm, used with additional special barrier or sealing layers for a circuit board. Metal or metal oxide layers are omitted to improve biodegradability.

[0010] JP 6635355 B2 discloses a packaging laminate made of polyolefins, some of which are of non-fossil origin, and paper as a substrate. The polyolefin layer is extruded directly onto the paper. The laminate has a total thickness of 10–100 µm. Because the polyolefin is extruded onto the paper, subsequent separation is virtually impossible. Therefore, the material is not recyclable. AT 522 884 B1 discloses a recyclable paper packaging with a high barrier against water vapor and oxygen.

[0011] These packaging laminates typically suffer from the problem that the tear resistance is dominated by the plastic film, making it difficult to tear the packaging further. This can also cause the plastic film or coating to stretch so much that unwanted plastic particles can contaminate the food. Furthermore, it can cause problems when unpacking products with paper as the backing material, as the plastic film prevents further tearing due to its high elongation at break. Finally, it is then immediately obvious to the consumer that plastic is present in the packaging.

[0012] The present invention aims to provide a packaging laminate that has sufficient barrier properties and exhibits the tear resistance of paper, but is nevertheless recyclable.

[0013] According to the invention, this is achieved by providing an unusually thin plastic film stretched in at least one stretching direction as a barrier film, wherein the barrier film has a layer thickness of 1 to 10 µm, preferably less than 5 µm and most preferably less than 3 µm, and wherein the elongation at break of the barrier film in the stretching direction is less than or equal to 180% and preferably less than or equal to 130%.

[0014] Within the scope of the present invention, it is therefore possible to stretch the barrier film in a first stretching direction. It is also possible to stretch the barrier film in a second stretching direction. The barrier film can be stretched exclusively in a first stretching direction or exclusively in a second stretching direction. However, the barrier film can also be stretched in both a first and a second stretching direction. Stretching in both a first and a second stretching direction is usually referred to as biaxial or bidirectional stretching. If the barrier film is stretched in two stretching directions, then the elongation at break of the barrier film is advantageously less than or equal to 180% in both stretching directions, preferably less than or equal to 130%.

[0015] Due to the high stiffness and low elongation at break of the barrier film, the entire packaging laminate surprisingly adopts the tear properties of paper. This is advantageous for unpacking the contents and makes it possible to provide consumers with paper packaging offering high barrier properties. Despite this, the plastic does not affect the tear behavior of the packaging laminate. Ideally, the consumer also does not notice the small amount of plastic present in the packaging due to the paper-like tear properties.

[0016] The packaging laminate according to the invention consists of a paper backing layer and a barrier film made of thermoplastic material, such as polyolefins or polyesters. The backing layer is made of paper of any type and is composed of material containing cellulose, hemicellulose, and / or lignin, with the exception of glassine. Although both glassine and paper are derived from cellulose, glassine differs fundamentally in structure from paper because the types of fiber milling used in their production differ. Paper can be produced, for example, from pulp, wood pulp, recycled paper pulp, or agricultural waste such as cup plant, grass, straw, and similar materials. The backing layer has a basis weight of 40–120 g / m².

[0017] In an advantageous embodiment, the substrate layer consists of uncoated paper. Uncoated paper includes all wood-free or wood-containing papers manufactured without synthetic ingredients. Its surface typically shows fine fibers, is somewhat rougher, and open-pored. Preferably, uncoated paper with a basis weight between 40 and 120 g / m² is used.

[0018] Advantageous thermoplastics can be, for example, polyolefins such as polyethylene (PE) in various types such as high-density polyethylene (HDPE) or low-density polyethylene (LDPE), polypropylene (PP) as a homopolymer, polybutylene (PB), polyisobutylene (PIB) and similar materials, which are considered suitable by experts in the field of packaging laminates.

[0019] Preferably, other thermoplastics, such as polyester, in particular polyethylene terephthalate (PET), can also be used for the packaging laminate according to the invention.

[0020] PP homopolymer can be produced using various methods and can exhibit different orientations of the chain residues. For such packaging laminates, oPP, which is produced via polymerization using Ziegler-Natta catalysts, can be used advantageously.

[0021] The elongation at break of the plastics is determined by a tensile test. The tensile test is performed according to the standard ASTM D882-12. The elongation at break is measured in %, and, if applicable, the tensile strength in N / mm² of the barrier film. The tensile test is carried out as follows: The prepared sample of the barrier film (100 x 15 mm) is subjected to a tensile force on the tensile testing machine until it breaks. The sample is clamped in the tensile testing machine so that its longitudinal axis coincides with the line of action of the tensile force. The zero point settings of the tensile force and displacement must be checked and ensured before starting the tensile test. The required strain rate is set to 50 mm / min. The sample strain is measured over the displacement range of the tensile testing machine.For use in a packaging material 1 according to the invention, the barrier film in the desired thickness range of 1 to 10 µm should have an elongation at break of less than or equal to 180% and preferably less than or equal to 130%.

[0022] Preferably, the barrier film can be optically transparent or semi-transparent. Transparency means that the material exhibits little or no absorption in the visible range of the electromagnetic spectrum. This can be achieved, for example, with a plastic film containing partially transparent PP, such as cast PP, axially oriented PP, amorphous PP, or crystalline PP. Atactic and isotactic PP are also conceivable. PET can also be processed in an amorphous form and is thus available as a transparent material, as is common in beverage bottles. The thickness of the plastic film can also influence the transparency. This allows the packaging laminate to take on the color of the paper. Furthermore, it can be advantageous for various types of printing on the substrate or the barrier film.

[0023] To generate the elongation at break according to the invention, the barrier film is stretched in at least one direction. Stretching refers to the deformation of the plastic film in one direction, such as longitudinal deformation in the machine direction (MD, "Machine Direction") or deformation perpendicular to the machine direction (transverse direction TD, "Transverse Direction"), both exceeding the elastic yield strength. The machine direction can correspond to a first stretching direction and the transverse direction to a second stretching direction. This aligns the plastic fibers in the direction of the longitudinal deformation and thus, among other things, achieves the desired elongation at break properties. It is also conceivable that the barrier film is stretched biaxially, i.e., in both directions. This can be advantageous if the barrier film is to have a desired anisotropy, for example, to be more tearable in a preferred direction.

[0024] Optical transparency can also be advantageous in meeting consumer demand for sustainable packaging. Paper is generally perceived as natural or sustainable, while plastic is often considered environmentally harmful. A thin plastic film, such as in the barrier film according to the invention, can preserve the feel of the paper and offers several other advantages, such as increased puncture resistance and improved barrier properties compared to pure paper packaging. According to the invention, the tear properties, such as tear resistance, should be as close as possible to those of pure paper packaging so that the feel of the composite laminate and its tearing behavior are comparable to those of pure paper packaging.

[0025] The polymer in the barrier film can itself possess good barrier properties against oxygen, water vapor, grease, carbon dioxide, aromatic and saturated mineral oil components, and aromas. Polymer films act like diffusion membranes, especially for nonpolar substances, and can be described according to the solution-diffusion model for individual substance classes. The barrier effect can therefore vary depending on the substance class. To ensure a barrier effect for substances that are readily permeable through the plastic film, an additional barrier layer can be applied to the barrier film. Preferably, barrier layers can consist of metals, metalloids, or oxides. Metals can be applied in thin layers, for example, via sputtering, also known as cathode sputtering.In this process, a voltage is applied between a metal cathode and an anode ring, and a plasma is ignited, which removes metal atoms from the cathode and deposits them on a substrate.

[0026] Physical or chemical vapor deposition are also conceivable. Physical vapor deposition is similar to sputtering but can also be processed using electric arcs and lasers, for example. Chemical vapor deposition can utilize precursors that react within the chamber to form a thin layer. AlO₂₅ and SiO₂₅, for instance, can be applied as pure metals, subsequently forming an oxide layer, or they can be chemically deposited using suitable precursors.

[0027] Barrier layers made of plastics are also conceivable. Preferably, polyamide (PA) or ethylene-vinyl alcohol copolymer (EVOH) are used. These can be applied as a coating. However, it is also conceivable, and usually more economical, to co-extrude the plastic film together with the barrier layer. Preferably, the well-known blown film or flat film extrusion process is used.

[0028] The barrier layer can also be coated with a protective lacquer, primarily to protect against microcracking, which can impair the barrier function. Such a barrier layer can also achieve a low OTR and a low WVTR. Additionally, the substrate layer can also be coated with a barrier layer, a substrate barrier coating. Different barrier layers can be advantageous to achieve a desired specific transfer rate. Depending on the barrier layer, the thickness varies and can range from 0.01 to 1 µm.

[0029] Both components, the backing layer and the barrier film, can be designed for easy separation. This can be important during a recycling pulping process, allowing the barrier film to be separated and recycled separately. The paper backing layer can then be reused as waste paper after processing.

[0030] The barrier film is bonded to the carrier layer by means of a bonding layer. The bonding layer is preferably a wet-applied laminating adhesive.

[0031] Laminating adhesives are adhesives that are applied wet to a layer using a roller and ensure sufficient bond strength between two layers in a packaging laminate. A laminating adhesive can be hydrophilic, causing the adhesive bonds, such as hydrogen bonds, to weaken upon contact with moisture or water, leading to separation of the layers. Alternatively, the laminating adhesive itself can be water-soluble, such as starch- or protein-based laminating adhesives. Such a laminating adhesive can be advantageous in the recycling process because the polymer components of the barrier film can be easily removed from the paper. This type of laminating adhesive preferably has a dry application weight of 0.5 to 5 g / m². However, a laminating adhesive can also be hydrophobic, ensuring strong bond strength even in humid environments.

[0032] The layer thickness of the packaging laminate can be in the range of 40 to 130 g / m² or approximately 40 to 130 µm, the barrier film can preferably be used in a range of 1 to 10 µm and preferably in a range of less than 5 µm, most preferably in a range of less than 3 µm.

[0033] When recycling packaging laminate, it is typically soaked in water at a specific temperature and for a specific time (pulling process) after mechanical shredding. Due to the properties of the packaging laminate according to the invention, the carrier layer can detach from the barrier film during the pulping process, along with all layers and potential contaminants for paper recycling. A hydrophilic or water-soluble bonding layer reacts with the water during the pulping process, losing its adhesive properties or dissolving completely in the water, thus separating the carrier layer from the barrier film. The carrier layer can then dissolve in the water and form pulp, from which recycled paper can be produced.For recycling the packaging laminate, it is advantageous if the carrier layer loses sufficient adhesion or dissolves at a water temperature of 40°C within a maximum of 20 minutes, preferably a maximum of 10 minutes, and particularly preferably a maximum of 5 minutes, so that the carrier layer and the barrier film can be easily separated.

[0034] Since the barrier layer (if provided) can remain on the detached barrier film after separation during the pulping process in paper recycling, the recycled paper does not become greyish, which would inevitably happen with barrier metallization of a paper surface.

[0035] The present invention is described below with reference to the Figuren 1 bis 6 In more detail, the invention is explained, and exemplary, schematic, and non-restrictive embodiments are shown. This includes showing Fig.1 a packaging laminate according to the invention with barrier film, Fig.2 an advantageous embodiment of the packaging laminate with barrier layer, Fig.3 a package with packaging laminate according to the invention, Fig.4 a pouch packaging with packaging laminate according to the invention, Fig.5a the stress-strain diagram of the packaging laminate according to the invention, Fig.5b the stress-strain diagram of a packaging laminate in the prior art, Fig.6a the crack patterns of packaging laminate according to the invention, and Fig.6b The crack patterns of a packaging laminate in the state of the art.

[0036] Fig. 1 Figure 1 shows a packaging laminate 1 according to the invention. The packaging laminate 1 basically consists of a carrier layer 2 and a barrier film 4. The barrier film 4 is a plastic film and may additionally have a barrier layer 5 applied to it. The carrier layer 2 is connected to the barrier film 4 by means of a bonding layer 3.

[0037] The second support layer is made of paper. Paper is defined as any type of material consisting of cellulose, hemicellulose, or lignin-containing material, with the exception of parchment. Although parchment is made from cellulose, it differs fundamentally from paper in its structure because the types of fiber milling used in its production differ. Paper can be made, for example, from pulp, wood pulp, or recycled paper pulp (or mixtures thereof). The paper used can be food-grade and coated or uncoated. Preferably, the paper is untreated on both sides and free of foreign matter, thus being a so-called uncoated or natural paper, meaning, for example, without layers of polymers as found in commercially available coated paper.The paper of the carrier layer 2 can also have a coating, usually made of a polymer. The carrier layer 2 itself can, for example, possess sufficient barrier properties against water vapor and oxygen.

[0038] The carrier layer 2 can also be provided with a carrier barrier coating. The carrier barrier coating can comprise at least one polymer selected from the group consisting of at least one polyvinyl alcohol, preferably in the form of a homo- or copolymer, PVDC, biopolymers, polyester, casein, starch, thermoplastic starch, sugar, cellulose, carboxymethylcellulose, cellulose ethers, xanthan gum, carrageenan, polypeptides, proteins, gelatin, pectin, guarana, chitin derivatives, chitosane derivatives (in particular N-carboxymethyl chitosan), dextran, gluten, hyaluronic acid, polyhydroxyalkanoate-based water-soluble polymer, ionomers, polyurethane, an ethylene vinyl laurate alcohol copolymer, one or more copolymers of a polyester and aliphatic epoxides, one or more copolymers of an (alkylated / arylated) acrylate and aliphatic epoxides, or one or more homo- or copolymers of polyvinylpyrolidone.one or more cycloolefin copolymers (COC), particularly preferably based on norbornene polymers (COP) and preferably on norbornene-ethylene copolymers (COC), (partially or fully hydrogenated), polyamides, cellulose derivatives, one or more soluble polycarbonate copolymers individually or in a combination of several of the polymers included in the group, and preferably a crosslinking component from the group consisting of isocyanates, amines, anhydrides, oxazolines, azeridines, reactive silanes, dicarboxylic acids.

[0039] If the carrier layer 2 has a carrier barrier coating, the carrier barrier coating can be applied to the side of the carrier layer 2 facing the bonding layer 3. Alternatively, the carrier barrier coating can also be applied to the side of the carrier layer 2 facing away from the bonding layer 3. It is also possible to apply a carrier barrier coating to both the side of the carrier layer 2 facing the bonding layer 3 and the side facing away from the bonding layer 3.

[0040] According to the invention, the carrier layer 2 has a basis weight of 40 to 120 g / m² and is thus, as in Fig.1 As indicated, it is significantly thicker than the barrier film 4. The packaging laminate 1 is therefore designed asymmetrically.

[0041] The barrier film 4 can be a thermoplastic, in particular polyolefins or polyesters. In a preferred embodiment, the barrier film consists of polypropylene (PP) in the form of a homopolymer, high-density polyethylene (HDPE), ethylene-vinyl alcohol copolymer (EVOH), or polyester, such as polyethylene terephthalate (PET). The barrier film 4 is stretched in at least one direction. Preferably, the barrier film 4 can also be biaxially stretched to produce comparable elongation at break properties in both film directions. Stretching is defined as longitudinal deformation in the machine direction (MD), and, in the case of bidirectional stretching, also in the transverse direction (TD) normal to the machine direction, beyond the elastic yield strength. This causes the plastic fibers to align in the direction of the longitudinal deformation and thereby, among other things, achieve the desired elongation at break properties.Preferably, stretching is performed with a stretch ratio of 1:2 to 1:10 in MD and 1:2 to 1:10 in TD.

[0042] Stretching can also improve the barrier properties of barrier film 4 compared to an unstretched plastic film. Other properties of a plastic film, such as optical transparency, can also be influenced by stretching.

[0043] The carrier layer 2 and the barrier film 4, which is stretched in one direction, are bonded together via a bonding layer 3. The bonding layer 3 is preferably a laminating adhesive. Laminating adhesives can, for example, be hydrophilic and lose their bond upon contact with moisture, which can improve or facilitate the recycling of the packaging laminate 1. Suitable polar bonding layers 3 preferably consist of polymers with increased polarity, for example, maleic anhydride-grafted polyolefins (such as PE or PP), ethylene-vinyl acetate copolymer (EVA), ethylene / acrylic acid copolymer (EAA), ethylene butyl acrylate copolymer (EBA), or similar polyolefin copolymers, or even polyurethane. Compostable and water-soluble materials such as starch- or protein-based adhesives are also conceivable. The bonding layer 3 preferably has a coating weight in the dried state of 5–0.5 g / m², most preferably below 2.5 g / m².

[0044] In a preferred embodiment, a barrier layer 5 can be applied to the barrier film 4. The barrier layer 5 preferably consists of a layer of a (semi)metal or (semi)metal oxide. In a preferred embodiment, the barrier layer 5 consists of AlO₂, SiO₂, or a metallization, preferably with aluminum. The barrier layer 5 can be applied by chemical or physical vapor deposition (CVD or PVD), or, preferably in the case of metals, by sputtering. In this case, the barrier layer 5 is applied to the barrier film 4 after stretching.

[0045] In another possible embodiment, the barrier layer 5 is a layer made of a barrier polymer, i.e., a polymer with sufficient barrier properties. The barrier polymer is preferably a polyamide (PA) or an ethylene-vinyl alcohol copolymer (EVOH). EVOH is preferably used as the barrier polymer. Such a barrier layer 5 can, for example, be co-extruded, extrusion-laminated, or laminated with the barrier film 4. In the case of extrusion lamination or lamination, a suitable laminating adhesive is provided for bonding the barrier layer 5 and the barrier film 4.

[0046] Additionally, a protective varnish can be applied to the barrier layer 5, which can further improve the barrier properties. In a preferred embodiment, the packaging laminate 1 consists of a carrier layer 2, a barrier film 4, a barrier layer 5, and a protective varnish layer (any bonding layers are not mentioned).

[0047] Depending on the design and material, barrier layer 5 can increase barrier properties against water vapor, oxygen, aromatic and saturated mineral oil components, grease, carbon dioxide and / or aroma.

[0048] Barrier properties are preferably specified in terms of specific transfer rates. Uncoated plastic films have typical OTR ranges of 40–60 cm³ / (m² * d * bar) (where "d" stands for day) and typical WVTR ranges of 260–500 cm³ / (m² * d * bar). A barrier layer 5, such as a metallization, can significantly improve these properties. For oxygen, a preferred OTR of less than 5 cm³ / (m² * d * bar) (where "d" stands for day), and most preferably less than 1.5 cm³ / (m² * d * bar), can be achieved. For water vapor transfer rate (WVTR), a value of 5 cm³ / (m² * d * bar) can preferably be achieved, and values ​​less than 1 cm³ / (m² * d * bar) are most preferably achieved for high-quality products. For aromatic and saturated mineral oil components less than 12 g / (m 2< xd) measured at 23°C and 50% relative humidity (r. h).A KIT value of 12 was determined for grease resistance, measured according to Tappi 559 ("Grease resistance test for paper and paperboard, Test Method T 559 cm-12"). The KIT value is divided into a scale from 1 to 12, with 12 representing the highest barrier effect. There is no objective measure for aroma barrier; its effectiveness as an aroma barrier is determined subjectively through odor tests.

[0049] The barrier properties can only be achieved through a combination of carrier layer 2, barrier film 4, and barrier layer 5. For example, carrier layer 2 can provide the necessary oxygen and water vapor barrier, while barrier film 4 fulfills the necessary barrier properties for grease, mineral oil components, and aroma.

[0050] According to the invention, the barrier film 4 has a layer thickness d of 1 to 10 µm, preferably 5 to 1 µm. When using polyolefins in the barrier film 4, the thickness is most preferably less than 3 µm, and when using PET, it is most preferably less than 5 µm.

[0051] A barrier layer 5 of the barrier film 4 can, as in Fig. 2 The barrier layer 5 is shown to be arranged facing the bonding layer 3. However, it is also conceivable that the barrier layer 5 is arranged facing away from the bonding layer 3, i.e., on the outside when used in packaging. A barrier layer 5 in packaging facing the contents 6 can also be particularly suitable for contents that would attack the carrier layer 2, such as acidic foods.

[0052] Depending on the application, the bond strength between barrier film 4 and carrier layer 2 should be sufficiently high to prevent delamination of the packaging laminate 1. The bond strength is determined by a peel test. In this test, a test strip of the packaging laminate 1 is pulled apart at the free ends of the carrier layer 2 and the barrier film 4. The free ends are clamped in a pulling machine and pulled apart at a predetermined angle (e.g., 90°), and the force is measured. With a test strip width of 15 mm, the bond strength is expressed in N / 15 mm. For sufficient bond strength, the measured force must be at least greater than 0.5 N / 15 mm, preferably up to 3 N / 15 mm. Very good bond strength can also lead to paper fiber tearing or splitting in the plastic film or barrier layer 5.The specified bond strength is the nearly constant peel value, not the maximum initial force peak that occurs at the beginning of the peel test. Typically, a number of peel tests are performed to determine the bond strength, and the desired bond strength is calculated as the average of the individual measurements. The peel test is performed, for example, according to the standard ASTM F904.

[0053] According to the invention, the tear properties of the packaging laminate 1 are similar to those of pure paper packaging, but the barrier film 4 enables high barrier properties compared to pure paper packaging. The so-called tear resistance of the packaging laminate 1 is determined by its elongation at break and is influenced by the material used for the barrier film 4 and its thickness, optionally including the barrier layer 5. To achieve the tear resistance according to the invention, the elongation at break of the barrier film 4 in the stretching direction is less than or equal to 180%, preferably less than 130%. This applies to both stretching directions in the case of a bidirectionally stretched barrier film 4. By biaxially stretching the barrier film 4, the anisotropy with respect to the tear resistance in the two stretching directions can be kept as low as possible.This enables the tear properties of the laminate according to the invention as described in . Fig. 5a depicted.

[0054] In the case of an additional barrier layer 5 and / or protective coating layer, the elongation at break of the barrier film 4 with the additional barrier layer 5 and / or protective coating layer should not exceed 180%. Therefore, very tough materials for the barrier layer 5 and / or protective coating layer may be unsuitable for this application.

[0055] The following is a comparison of a packaging laminate 1 according to the invention with a packaging laminate from the prior art.

[0056] The packaging laminate 1 according to the invention comprises a 70 g / m² paper as a carrier layer 2, which is laminated with a 4.5 µm thick PET film, as a barrier film 4, using a laminating adhesive. The laminating adhesive was applied with a basis weight of 1.5 g / m². Fig. 5a Figure 1 shows the stress-strain diagrams of the packaging laminate 1 according to the invention. The PET film used in the packaging laminate 1 according to the invention has an elongation at break of 95% in MD and 85% in TD and is commonly used in these thicknesses in technical applications as capacitor film.

[0057] The comparison example is a 42 g / m² paper, laminated as carrier layer 2 against a 12 µm PET film, which is typical for packaging applications of all kinds. Fig. 5b Figure 1 shows the stress-strain diagrams of the comparative example. The PET film (PETLAIN ​​from Superfilm) has an elongation at break of 140% in MD and 110% in TD. The barrier film 4 is therefore within the elongation at break range according to the invention, but outside the thickness range. This can cause problems when tearing packaging made from such a non-inventive packaging laminate (for example, when unpacking goods), since the plastic film in the barrier film 4 prevents easy further tearing due to its high thickness. This can be problematic when opening packaging. Furthermore, it can make it immediately apparent to the consumer that plastic is present in the packaging, which is often undesirable.

[0058] The tearing behavior can also be seen in the stress-strain diagram in Fig. 5a Read clearly. The packaging laminate 1 according to the invention tears at approximately 4% MD and approximately 6% TD. In the comparative example ( Fig.5b ) the paper tear is present at similar yield strengths, subsequently only the PET film of the barrier film 4 is stretched, which is evident in the plastic deformation range of the stress-strain diagram, and after tearing is also noticeable in a visible barrier film 4 ( Fig.6b Paper alone, with an exemplary basis weight of 70 g / m², has an elongation at break of MD 2.8%, TD 4.5%.

[0059] Crack patterns of the packaging laminate 1 according to the invention are shown in Fig. 6a shown. Comparing the stress-strain diagrams with the corresponding crack patterns ( Fig.6a ) of the packaging laminate 1 according to the invention, no separate plastic residue of the barrier film 4 is visible in the crack pattern. This corresponds to the stress-strain diagram, where only one crack area is visible, since the plastic of the barrier film 4 adapts to the cracking behavior of the paper of the carrier layer 2. The plastic of the barrier film 4 does not stretch and is therefore not perceived as bothersome by the consumer when tearing open the packaging and cannot be perceived as such. In contrast, in the crack pattern of the prior art ( Fig.6b The plastic film of the barrier film 4 is clearly visible below the paper of the carrier layer 2. The bonding layer 3 is not visible in the crack pattern in either case due to the relatively thin layer thicknesses.

[0060] In a preferred embodiment, the packaging laminate 1, in the form of a closure plate, can be sealed to a packaging container 7 via the barrier film 4 to create a package 9. For this to work, the barrier film 4 must be oriented towards the contents 6. The package 9 is in Fig. 3 The sealing plate is die-cut from the packaging laminate 1 according to the invention and sealed onto a sealing edge 8 of the packaging container 7 using a heat-sealing process. The sealing is preferably carried out on a sealing edge 8 of a packaging container 7, thereby achieving a tight connection between the packaging container 7 and the packaging laminate 1. The sealing temperature for conventional sealing layers 8 can, for example, be between 120°C and 290°C, but usually between 180°C and 250°C; however, the heat resistance of the carrier layer 2 used must be taken into account.

[0061] The packaging 9 can, for example, be intended for fatty foods packaged in portion-sized portions. In a preferred embodiment, such packaging 9 is suitable for portions of butter, hazelnut spread, but also for jam or honey. Even liquid contents are conceivable due to the high impermeability to liquids. Of course, larger quantities of food can also be packaged with the packaging laminate 1 according to the invention. No sealing is necessary for this, as in Fig.3 Given. Such packaging 9 can, for example, be folded from a section of the packaging laminate 1 and fixed using an adhesive, preferably a pressure-sensitive one. The packaging laminate 1 can be used, for example, for seasonal goods or fatty foods such as butter, cheese, etc. For this purpose, the paper carrier layer 2 can be oriented either towards the contents or towards the surroundings.

[0062] The packaging laminate 1 according to the invention can also be used to produce packaging in the form of a bag. For this purpose, the packaging laminate 1 can be cut to size and, for example, formed into a bag 11, for example by folding, and sealed at the overlaps, as shown in Fig.4 This is illustrated using the example of a bag 11 with a longitudinal seal 12 and two transverse seals 13. The packaging laminate 1 can also be processed directly in known continuous packaging machines, e.g., so-called form-fill machines or flow-wrapping machines. For sealing, the folded, overlapping packaging laminate 1 is pressed together at the sealing point between two temperature-controlled sealing jaws. In all cases, the sealing layer of the packaging laminate 1, which is formed by the barrier film 4, is sealed either against its own sealing layer or against the carrier layer 2.

[0063] The carrier layer 2 or the entire packaging laminate 1 can be embossed. A patterned embossing can be executed as a worm embossing, linen embossing, line embossing, wave embossing, halftone embossing, dot embossing, needle embossing, damask embossing, image embossing, lettering embossing, Braille embossing, or combinations thereof. Thus, on the one hand, inexpensive and existing embossing calenders can be used, and on the other hand, embossing calenders specifically manufactured for the respective product can be used, whereby the patterned embossing gives the product an attractive appearance in any case.

Claims

1. A packaging laminate (1) consisting of a carrier layer (2) and a barrier film (4), wherein the carrier layer (2) consists of paper with a grammage of 40 to 120 g / m2, wherein the barrier film (4) is connected to the carrier layer (2) via a connecting layer (3), wherein a plastics film stretched in at least one stretching direction is provided as the barrier film (4), wherein the barrier film (4) has a layer thickness of 1 to 10 µm, preferably less than 5 µm and very preferably less than 3 µm, and wherein an elongation at break of the barrier film (4) in the at least one stretching direction is less than or equal to 180%, preferably less than or equal to 130%, which elongation at break can be determined via a tensile test according to the ASTM D882-12 standard.

2. The packaging laminate (1) according to claim 1, characterized in that the barrier film (4) is stretched biaxially in a first stretching direction and in a second stretching direction.

3. The packaging laminate (1) according to claim 2, characterized in that an elongation at break of the barrier film (4) in the first stretching direction is less than or equal to 180%, preferably less than or equal to 130%, which elongation at break can be determined via a tensile test according to the ASTM D882-12 standard, and in that an elongation at break of the barrier film (4) in the second stretching direction is less than or equal to 180%, preferably less than or equal to 130%, which elongation at break can be determined via a tensile test according to the ASTM D882-12 standard.

4. The packaging laminate (1) according to claim 1, characterized in that the barrier film (4) consists of polypropylene homopolymer, polyethylene, EVOH copolymers or polyethylene terephthalate.

5. The packaging laminate (1) according to claim 1, characterized in that the barrier film (4) has a barrier layer (5), which barrier layer (5) has a layer thickness of 0.01 to 1 µm and wherein the elongation at break of the barrier film (4) with the barrier layer (5) is not higher than 180%.

6. The packaging laminate (1) according to claim 5, characterized in that the barrier layer (5) consists of AlOx, SiOx or a metallization, preferably of aluminum.

7. The packaging laminate (1) according to claim 5, characterized in that the barrier layer (5) consists of EVOH copolymers or polyamide.

8. The packaging laminate (1) according to claim 1, characterized in that the carrier layer (2) consists of uncoated paper.

9. The packaging laminate (1) according to claim 8, characterized in that the carrier layer (2) has a carrier barrier coating.

10. A packaging (9) having a packaging container (7), characterized in that a closure panel made of the packaging laminate (1) according to claims 1 to 9 is sealed to a sealing edge (8) of the packaging container.

11. A packaging (9) in the form of a bag (10), characterized in that a packaging laminate (1) according to claims 1 to 9 is folded and sealed at overlapping points after folding.

12. A method for producing a packaging laminate (1), wherein a barrier film (4) stretched in at least one stretching direction is provided with a layer thickness of 1 - 10 µm, preferably less than 5 µm and most preferably less than 3 µm, and with an elongation at break in stretching direction of less than or equal to 180%, preferably less than or equal to 130%, and a carrier layer (2) of paper with a grammage of 40 to 120 g / m2 is provided, and a connecting layer (3) is applied to the barrier film (4) and / or to the carrier layer (2), and the barrier film (4) and the carrier layer (2) are connected to one another via the connecting layer (3), wherein the elongation at break can be determined via a tensile test according to the ASTM D882-12 standard.