Laminate, in particular for producing packages, use of a laminate for producing packages, and packages produced from a laminate and method for producing a laminate

Abstract

The invention relates to a laminate (10), in particular for producing packages, having an optionally designed outer layer (15) and a sealing layer (50) arranged opposite the visible face of the outer layer (15), the sealing layer (50) preferably being a low-temperature sealing layer (78), wherein the sealing layer (50) is designed as the first blown film (70) or as the outermost layer of the first blown film (70); the outer layer (15) and the blown film (70) are arranged between the outer layer (15) and the blown film (70) and a first extruded laminate layer (60) is arranged, the use of such a laminate (10) and a package made of such a laminate (10), in particular a tubular bag package preferably capable of standing, and a method for producing such a laminate (10).

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a laminate according to the preamble of claim 1, the use of such a laminate for producing such a packaging according to the preamble of claim 16, a packaging produced from such a laminate according to the preamble of claim 17, and a method for producing a laminate according to the preamble of claim 18. PRIOR ART

[0002] Laminates for producing packages (such as tubular bags with or without a standing bottom) have long been known. According to the prior art, such laminates generally consist of a printable outer layer and a sealing layer, which is usually attached to the outer layer by an adhesive. To produce a package, two separate blanks of the laminate are sealed together using the sealing layers facing each other along the outer edge of the blank to form the package volume, whereby the filling opening of the package is naturally only closed after the contents have been filled into the package. Alternatively, instead of two separate blanks connected by a seal, a single blank can be used, which is folded so that the outer edges of the folded blank overlap each other in such a way that they are heat-sealed together by the opposing sealing layers, wherein the filling opening is only closed after the filling material has been filled into the package. According to the prior art, the seal between the two blanks or the folded blank is always carried out by pressing a sealing jig against the outer side of the corresponding outer layer adjacent to the sealing layer, which sealing jig has a high temperature that softens the two sealing layers to be sealed together, so that the corresponding polymer chains of the corresponding sealing medium can be fused together, thereby ensuring a tight seal and thus a reliable closure of the package.

[0003] A disadvantage of such laminates for producing such packages is that the corresponding sealing layer, which also imparts stability to the package, is very thick. Therefore, taking into account the fact that traditional polymers used for the sealing layer (such as polyethylene or polypropylene) are not good heat conductors, it is problematic to transfer the heat energy required to melt the surface to be sealed to the surface to be sealed, because the heat transfer from the sealing jig must first pass through the outer layer of the corresponding laminate blank, then through the adhesive used and into the sealing layer, whereby the sealing layer must be almost completely melted before an effective sealing process can take place, due to the fact that its surface to be sealed is located on the opposite side of the introduced heat energy. However, since the sealing layers used according to the prior art to date have a very high thickness (i.e., in the range of greater than 50 μm, but usually even in the range of 100 μm to 140 μm), a very high heat input is necessary to ensure a good and tight seal, which must be applied either by a very high temperature of the sealing jig or by a very long dwell time of the sealing jig on the corresponding outer layer of the laminate.

[0004] However, such a high sealing temperature (e.g., above 130 °C) is necessary for sealing laminates that have been commonly used to date, which have the inherent drawback that not all materials are suitable for use as the outer layer because their integrity and / or appearance are impaired by the application of such heat-sealing fixtures, which in turn results in packages produced in this way being no longer attractive and no longer saleable.

[0005] Optionally, as described above, the dwell time of the sealing fixture on the respective outer layer of the laminate can also be extended. Depending on the materials used, if the outer layer is not completely melted due to the long dwell time, there is no risk of denaturation of the outer layer. However, due to the necessary long dwell time of the sealing fixture on the respective outer layer of the laminate, the production speed is significantly reduced, which in turn has an extremely negative impact on the productivity during the production of the packages and the sealing of the packages after filling.

[0006] In addition, the two alternative options (i.e., increasing the temperature of the sealing fixture and extending the dwell time of the sealing fixture on the outer layer of the laminate) also result in an undesired increase in the cost of producing the packages and thus also in an increase in the total cost of the package products. Of course, another factor that leads to a further increase in the cost of producing packages using previously known laminates is that due to the large thickness of the sealing layer of these laminates (which has been necessary to date), the material requirements for the sealing medium are very high, which in turn is disadvantageous due to the cost of the sealing medium.

[0007] Due to the necessity of using adhesives, a further disadvantage of the laminates at the front line is also the poor chemical resistance, the typical low bond strength / adhesion strength of extruded laminated thick (>50 μm) cast LLDPE and polypropylene films, and polypropylene blown films, which is also manifested in poor drop tests. SUMMARY OF THE INVENTION

[0008] The present invention is based on the object of providing an alternative, cost-effective laminate that is suitable for producing packages and avoids the above-mentioned drawbacks. In addition, an object of the present invention is also to be able to use such a laminate to produce packages and to provide packages produced from such a laminate.

[0009] According to the present invention, this object is achieved by the laminate according to claim 1, the use of such a laminate according to claim 16 for producing packages, the package produced from such a laminate according to claim 17, and the method for producing a laminate according to claim 18.

[0010] In particular, the object of the present invention is achieved by a laminate, in particular a laminate for producing a packaging element, which has an outer layer that can have a design and a sealing layer arranged opposite the visible side of the outer layer, wherein the sealing layer is preferably a low-temperature sealing layer, and the low-temperature sealing layer is formed as a first blown film or the outermost layer of the first blown film, and a first extrusion laminating layer is arranged between the outer layer and the blown film.

[0011] The basic core of the present invention lies in that, according to the present invention, the sealing layer is designed as a low-temperature sealing layer. Herein, the term "low-temperature sealing layer" means that the sealing layer according to the present invention is a very thin layer in the range of 2 μm to 40 μm, preferably in the range of 3 μm to 30 μm, and particularly preferably in the range of 4 μm to 20 μm, which is formed as a blown film (i.e., a single-layer blown film) by itself or as the outermost layer of a multi-layer blown film. The main advantage of the blown film used as the low-temperature sealing layer or the outermost layer of the blown film is that the material thickness of the sealing layer according to the present invention is very thin, and when the sealing fixture is applied to the outer layer, it is heated to the initial sealing temperature very quickly, that is, almost spontaneously, rather than in the prior art, where the thickness of the sealing layer is in the range greater than 50 μm, but most of them are even in the range of 100 μm to 140 μm, and a large amount of sealing medium must be heated first in order to reach the initial sealing temperature on the outermost side of the laminate opposite the visible side of the laminate.

[0012] In the context of the present invention, the initial sealing temperature is understood as the temperature at which the outer surface of the sealing layer melts, so that it is possible for the outer surface of the sealing layer to fuse with the corresponding object to be sealed.

[0013] Another main advantage of the present invention is that the laminate according to the present invention has a first extrusion laminating layer between the outer layer and the blown film. In this way, the combination of the outer layer and the blown film is possible without using an adhesive, and thus the laminate according to the present invention is formed during the extrusion laminating process, wherein the extrusion laminating layer is introduced between the outer layer and the blown film in a molten state. In this way, the best combination between the outer layer and the blown film is possible, and by introducing the extrusion laminating layer between the outer layer and the blown film in a molten state, a tight and almost optimal thermal contact is established between the outer layer and the blown film, so that the heat transfer from the outer layer to the surface of the sealing layer is actually unhindered and very fast, that is, in the range of a few milliseconds to about 50 milliseconds, that is, almost spontaneously.

[0014] According to an embodiment of the present invention, a second extrusion laminating layer facing the outer layer, in particular a second extrusion laminating layer arranged adjacent to the outer layer, and a second blown film combined with the second extrusion laminating layer are arranged between the first extrusion laminating layer and the outer layer, wherein the second blown film is combined with the first extrusion laminating layer.

[0015] According to this embodiment, the above-mentioned base laminate according to the invention extends in a sandwich-like manner through a second extrusion laminate layer and an adjacent second blown film, wherein in this case, the second extrusion laminate layer forms a bonding layer with the outer layer, and the second blown film is a bonding layer with the first extrusion laminate layer. As described above, the first blown film having its outer sealing layer is attached thereto.

[0016] For the production of this embodiment of the invention, since the second extrusion laminate layer is introduced into the layer composite of the laminate according to the invention by tandem extrusion lamination, i.e., simultaneously with the first extrusion laminate layer, there is a tight bond between the respective layers of the entire composite, which simultaneously ensures optimal heat transfer from the outer layer to the surface of the sealing layer.

[0017] At the same time, the sandwich-like structure of the second blown film, the first extrusion laminate layer, and the first blown film according to the invention, similar to double glazing or laminated glass in window glass, significantly improves the stability of the laminated structure, even if the combined thickness of the second blown film, the first extrusion laminate layer, and the first blown film is less than the original thickness, i.e., the thickness used for this purpose according to the prior art and the sealing layer that initially provided stability.

[0018] According to an embodiment of the invention, the first blown film and / or the second blown film is made from a melt of the polymer forming the respective layers of the first blown film and the second blown film and is therefore unoriented.

[0019] According to another embodiment of the invention, the first blown film and / or the second blown film is composed of a plurality of blown film layers, preferably stretched, especially in the machine direction and / or the transverse direction of the machine direction. In addition, the first blown film and / or the second blown film each define a layer of the laminate as a whole.

[0020] In this regard, it should be noted that the term "stretching" of the film specifically refers to the stretching of the film below the melting point, typically 5 °C to 20 °C below the melting point of the film (i.e., the polymer forming the film or, in the case of a multi-layer film, the polymers forming the multi-layer film). Through this stretching, the unoriented polymers present in large quantities in the film are aligned in the stretching direction, and the stretching direction can thus be the machine direction and / or the transverse direction of the machine direction. By the orientation of the plastic film during the stretching process, in particular, the stiffness, tensile strength, and toughness of the film can be improved.

[0021] Therefore, during the production of the film by flat film extrusion or blown film extrusion (i.e., during the production of the film from the respective polymer melts), the specific orientation of the polymer molecules does not thus clearly constitute the stretching of the film produced by this method, which is also known, for example, from EP 4 076 944 B1.

[0022] According to the present invention, the first blown film and the second blown film can thus have different functional layers and thus different functionalities. For this purpose, both the first blown film and the second blown film are produced in the blowing units respectively assigned to them. The first blown film and the second blown film can each have the same structure. However, optionally, the first blown film and the second blown film can also have different properties and different transparencies.

[0023] According to a preferred embodiment of the present invention, the first blown film and the second blown film can have different respective material qualities, whereby the second inner blown film can have a lower material quality than the first outer blown film. At the same time, the second inner blown film can have a greater layer thickness or material thickness, such that the second inner blown film mainly contributes to the structural safety, rigidity and stability of the laminate according to the present invention, while the first outer blown film can be thinner than the second inner blown film and is decisive for a very good sealing of the laminate according to the present invention.

[0024] Thus, in an advantageous manner, by using only high-quality materials for the respective outer laminate layers, the cost of producing the laminate according to the present invention can be reduced, while the laminate layers enclosed in the laminate can be of lower quality, since their optical appearance, for example, is irrelevant to the laminate according to the present invention, as they are enclosed between the outer laminate layers and are thus invisible. However, it should be noted that any possibly used lower-quality inner laminate layers according to the present invention still ensure a very good bond strength between the individual laminate layers.

[0025] Thus, the first blown film and / or preferably the second blown film can have at least one barrier layer material, which is integrated into the first blown film and / or preferably the second blown film in the form of a blown film layer.

[0026] According to the present invention, the barrier layer material is selected from optionally stretched high-density polyethylene (HDPE), ethylene-vinyl alcohol copolymer (EVOH) and / or polyamide, in order to impart on the one hand a high gas impermeability to the respective blown film and thus also to the laminate according to the present invention, and on the other hand also a moisture and water vapor impermeability.

[0027] In addition to the barrier layer material integrated into the first blown film and / or the second blown film in the laminate according to the present invention, the laminate according to the present invention can have at least one further barrier layer, which is in the form of a metallized layer, an alumina and / or silica layer, or a metal layer, in particular an aluminum or aluminum composite, which is arranged adjacent to the first blown film and / or preferably adjacent to the second blown film, particularly preferably on the side of the second blown film facing the outside.

[0028] Within the scope of the present invention, with reference to EP 3 067 437 B1, the term "aluminum bonding" refers to a method of depositing aluminum metal on a surface (such as a first blown film and / or preferably a second blown film) in an oxygen-rich environment, such that a metal layer surrounded by aluminum oxide is deposited in the form of an aluminum oxide - aluminum metal - aluminum oxide (AlO x -Al-AlO x ) layer on the surface of the blown film to be coated. During this process, the surface of the blown film to be coated is exposed to oxygen both before and during metal deposition, such that an oxygen-rich metal oxide layer is formed between the film layer surface and the deposited metal, which significantly improves the adhesion between the film surface and the aluminum-containing layer.

[0029] In a particularly advantageous manner, in this way, the laminate according to the present invention has a water vapor permeability of less than 0.5 g / m 2 / day in an environment with a relative humidity of 85%, and when a metallized barrier layer is used in combination with EVOH, it can even reach a value of less than 0.1 g / m 2 / day. Similarly, the laminate according to the present invention has an oxygen permeability that can be reduced to less than 0.5 cm 3 / m 2 / day at a temperature of 23°C and a relative humidity of 85%, and when a metallized barrier layer is used in combination with EVOH, it is even reduced to less than 0.2 cm 3 / m2 / day. The oxygen permeability measurement is carried out according to DIN standard 53380-3. The measurement of water vapor permeability is carried out according to DIN standard 53122-2.

[0030] According to another embodiment of the present invention, the first blown film and / or the second blown film has an outermost layer composed of a terpolymer, which is composed of a mixture of ethylene, acrylic acid, and acrylate. Preferably, a terpolymer sold under the name "Nucrel TM AE" by The Dow Chemical Company Global Dow Center, 2211 H.H. Dow Way, Midland, Michigan 48674 (US) is used.

[0031] According to a preferred embodiment of the present invention, if the laminate according to the present invention is not formed in a sandwich-like manner by a second extruded laminate layer and a second blown film, but is formed only by a first extruded laminate layer and a first blown film, the terpolymer forms the outermost layer of the first blown film. If, in the above manner, the laminate according to the present invention further has a second extruded laminate layer and a second blown film in addition to the first extruded laminate layer and the first blown film, preferably only the second blown film according to the present invention has the terpolymer, in which case the terpolymer again forms the outermost layer of the second blown film. When using the terpolymer, the outermost layer of the first blown film or the second blown film is understood as the layer of the corresponding blown film that faces the outer layer in the laminate.

[0032] It has been found according to the present invention that by using the above-mentioned terpolymer based on ethylene, acrylic acid and acrylate as the outermost layer of the corresponding blown film facing the outer layer of the laminate, the adhesion between the blown film and the adjacent extruded laminate layer can be improved. Thus, when using such a terpolymer layer in the corresponding blown film, a metallized barrier layer can also be used between the blown film and the associated extruded laminate layer facing the outer layer.

[0033] According to another embodiment of the present invention, the first blown film and / or the second blown film contains titanium dioxide.

[0034] This embodiment is particularly suitable if the laminate according to the present invention is not clear (transparent). In this case, the first blown film or the second blown film can be colored white by using titanium dioxide. Thus, it is sufficient to provide a white pigment dye to the first blown film or the second blown film as required.

[0035] According to the present invention, the outer layer of the laminate according to the present invention selects a transparent film or a non-transparent film and, if necessary, a printed matter forming the design of the outer layer, wherein in the case of a transparent film, the printed matter is designed as a reverse printed matter (i.e., the printed matter on the side of the transparent film facing the sealing layer or the front printed matter on the opposite side (i.e., the outer side of the transparent film)), and in the case of a non-transparent film, it is designed as a front printed matter on the outer side of the non-transparent film.

[0036] According to the present invention, the material of the transparent film is polyethylene terephthalate, especially oriented polyethylene terephthalate, or alternatively a polyolefin, especially biaxially oriented polypropylene, or particularly preferably, optionally polyethylene stretched in the machine direction.

[0037] In addition, the first blown film and / or the second blown film contains low density polyethylene, especially LLDPE, as a material providing stability.

[0038] According to the present invention, it is particularly suitable to use LLDPE as the blow-molded film material providing stability, because LLDPE is the preferred material for producing thin blow-molded films, and it has been found according to the present invention that it is also a good sealable material, which is also suitable for particularly thin layers, especially layers bonded to each other, for producing very stable seals, as required for producing packaging parts using the laminate according to the present invention. Additionally, LLDPE is a plastic with low production cost, recyclable and harmless to health.

[0039] According to a particularly preferred embodiment of the present invention, the second blow-molded film is a composite of the following layers: terpolymer / HDPE / primer / EVOH / primer / HDPE / LLDPE or metallocene.

[0040] Advantageously, by using such a composite, a high-barrier laminate with very good impermeability values in terms of water vapor permeability and oxygen permeability can be produced, whereby the water vapor impermeability and oxygen impermeability can be further improved by stretching, especially in the uniaxial direction (i.e., in the blow-molding direction), as has been found according to the present invention. In this context, it should be noted that the terms "stretch" or "being stretched" and "orientation" or "being oriented" are used synonymously in the context of the present invention.

[0041] Furthermore, according to the present invention, the layers of the laminate have the following thicknesses or application weights:

[0042]

[0043]

[0044] An important aspect of the present invention is that instead of using a thick seal layer that is always thicker than 50 μm and usually even has a thickness in the range of 100 μm to 140 μm according to the prior art, a thinner layer with a maximum thickness of 60 μm but preferably thinner than or equal to 50 μm according to the present invention is used to produce a packaging part or seal with itself or the same corresponding seal layer. The use of such a thin layer according to the present invention is particularly relevant to the seal layer used according to the present invention, which, according to the present invention, only has a small fraction of the thickness of the previous ordinary layer and thus also has a small fraction of the heat capacity of the previous ordinary layer, and can therefore be sealed quickly, precisely, firmly and safely in a particularly easy manner, which was impossible for the previous thick seal layer in terms of the quality, precision and safety achievable according to the present invention, especially without damaging the laminate layers closer to the sealing clip during the sealing process.

[0045] According to another particularly preferred embodiment of the present invention, the laminate has a polyolefin content of greater than 90%, preferably greater than 95%, especially a polyethylene content of greater than 90%, preferably greater than 95%.

[0046] This high polyolefin content, and preferably even polyethylene content, of the laminate according to the invention results in particularly good recyclability of the laminate according to the invention, and can be achieved according to the invention by using polyethylene, in particular oriented polyethylene, for the outer layer, which polyethylene has particularly high rigidity and particularly good printability. In addition, according to the invention, polyethylene is used for the first extrusion laminate layer and the second extrusion laminate layer; this also applies to the production of the first blown film and the second blown film, which also comprises polyethylene, namely high-density polyethylene (in particular HDPE) or low-density polyethylene (in particular LLDPE), as the main material providing stability.

[0047] Therefore, according to the invention, in a particularly advantageous manner, materials other than polyethylene, such as adhesives, can be used substantially not at all, such that their proportion can be limited to less than 10%, preferably less than 5%, which optimizes the mechanical recyclability of the laminate according to the invention.

[0048] As described above, the laminate according to the invention is produced by extrusion lamination, in particular by tandem extrusion lamination, which makes it possible to produce a very tightly bonded and at the same time very thin composite, which essentially consists of an outer layer and a first blown film or two or three basic functional layers of an outer layer, a second blown film and a first blown film, wherein these basic functional layers, in particular the first blown film and the second blown film, can also comprise functional materials, such as barrier layers or dyes or terpolymers.

[0049] As described above, the object of the invention is also achieved by using the laminate according to the above to produce a packaging, in particular a tubular bag packaging, which is particularly capable of standing upright.

[0050] In addition, the object of the invention is also achieved by a packaging produced from the laminate according to the invention.

[0051] Furthermore, the object of the invention is also achieved by a method for producing the above laminate.

[0052] In particular, the object of the invention is achieved by a method in which the following steps are carried out:

[0053] - providing an outer film;

[0054] - during a single extrusion lamination, coating the outer film, if necessary using a primer as well as a first extrusion laminate layer and a first blown film arranged on the other side of the first extrusion laminate layer;

[0055] or

[0056] - providing an outer film;

[0057] In the case of necessity, the outer film is coated during the process of the tandem extrusion lamination process by using a primer, a second inner extrusion lamination layer, a second blown film disposed on the other side of the second extrusion lamination layer, a first extrusion lamination layer disposed on the other side of the second blown film, and a first blown film disposed on the other side of the first extrusion lamination layer.

[0058] Accordingly, the present invention and its advantages can be summarized as follows.

[0059] The laminate according to the present invention is suitable for flexible packaging, wherein the laminate is particularly suitable for being wound into a roll, and is firstly suitable for producing bag packages for all types of filled articles. According to the prior art, for such packages, a polyethylene adhesive film has been used so far, especially an LLDPE film adhesive with a thickness significantly greater than 50 μm, usually 100 μm to 140 μm, for example having the following structure: an oriented polyethylene terephthalate (OPET) with a thickness of 12 μm / printing layer / primer / >50 μm LLDPE film adhesive has been used.

[0060] The laminate according to the present invention is produced by single extrusion lamination or tandem extrusion lamination. For example, a laminate with the following layer structure can be produced: an oriented polyethylene terephthalate (OPET) with a thickness of 12 μm / printing layer / primer / second extrusion lamination layer, that is, an inner extrusion lamination layer with a polyethylene application weight of 20 g / m 2 / second blown film, that is, an inner blown film made of or substantially composed of linear low density polyethylene, especially LLDPE, with a total blown film thickness of 40 μm / first extrusion lamination layer, that is, an outer extrusion lamination layer with a polyethylene application weight of 20 g / m 2 / first blown film, that is, an outer blown film made of or substantially composed of linear low density polyethylene, especially LLDPE, with a total blown film thickness of 40 μm.

[0061] The advantage of the laminate according to the present invention over the laminates previously used for this purpose in the prior art lies in its very fast, precise and cost-effective manufacturability, especially because thin LLDPE films can be produced faster than thick LLDPE films, and thus are more productive, because it has been found according to the present invention that in the production of thin LLDPE blown films, a significantly higher (i.e., higher substantially in proportion to the lower thickness) area output can be achieved at the same mass output.

[0062] In addition, since the laminate according to the present invention does not contain adhesives, the laminate according to the present invention exhibits guaranteed high bonding strength, excellent chemical resistance, and significant cost advantages, because the laminate according to the present invention does not require a curing time during the production process, and also because adhesives are not used during the production process. Due to the blown film and single or tandem extrusion technologies, the production process is more cost-effective, especially because according to the present invention, inexpensive resins are used for the sandwich LLDPE film. According to the present invention, the sealing layer at the joint between the laminated layers can be produced during the production process of the package, which is significantly thinner than the prior art, and most importantly, can be produced at a lower temperature and thus faster, thereby achieving significantly better package value (added value) compared to the adhesive laminates known from the prior art so far.

[0063] In addition, compared with the adhesive laminates currently known in the prior art and the laminates using thick (i.e., at least 50 μm, but usually 100 μm to 140 μm thick) LLDPE sealing films known in the prior art, the novel laminate according to the present invention provides better "drop test" results.

[0064] Therefore, the laminate according to the present invention has the advantage that it can be produced by single or tandem extrusion lamination of a printable or printable film, which can be composed of various materials, such as oriented polyethylene terephthalate (OPET), biaxially oriented polypropylene (BOPP), oriented polyamide (OPA), low uniaxially oriented polyethylene (MDO-PE), whereby a very thin primer is coated on the entire printing surface. The coating weight of the solvent-based primer or preferably the water-based primer ranges from 0.2 g / m 2 to 2 g / m 2 , preferably ranges from 0.3 g / m 2 to 1 g / m 2 , and particularly preferably ranges from 0.4 g / m 2 to 0.6 g / m 2 . According to the present invention, this corresponds to a layer thickness in the range of 0.2 μm to 2 μm, preferably in the range of 0.3 μm to 1 μm, and particularly preferably in the range of 0.4 μm to 0.6 μm. The above-mentioned other layers are applied simultaneously during the above single or tandem extrusion lamination process, that is, the polyethylene application weight is preferably 20 g / m 2 ±5 g / m 2 of a thin extruded polyethylene coating and a thin blown film with a total thickness of less than 50 μm, preferably in the range of 25 μm to 40 μm in the case of single extrusion lamination, or possibly applied in a sandwich structure as described above (i.e., in the case of tandem extrusion lamination).

[0065] Accordingly, the main advantage of the present invention is that the expensive problem of adhesively laminating a thick (>50 μm) LLDPE film to a printed substrate, which has been used hitherto, can be overcome by applying a single or tandem extrusion composite to the printed substrate. In the case of single extrusion, the composite is a thin (<50 μm) LLDPE film and an extruded polyethylene coating, or in the case of tandem extrusion, two thin (<50 μm) LLDPE films and two extruded polyethylene coatings having a sandwich-like structure. The printed substrate can also be unprinted.

[0066] Furthermore, for the present invention, by using the thin (<50 μm) LLDPE film according to the present invention together with the aforementioned extruded coating, the previously always extremely low adhesive strength of the thick (>50 μm) LLDPE film in extrusion lamination can be overcome. Wherein, in the case of using a tandem extrusion device, two, or in the case where the extrusion device extends beyond the tandem extrusion device, multiple thin (<50 μm) LLDPE films together with their respective corresponding extruded polyethylene coatings can also be applied to a support film, such as a printed substrate.

[0067] In this way, a monolayer or tandem-extruded thin (<50 μm) LLDPE film can be advantageously obtained to replace the adhesively laminated thick (>50 μm) LLDPE film.

[0068] Other embodiments of the present invention are obvious from the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The present invention will be described below by way of exemplary embodiments, and the exemplary embodiments will be explained in more detail with reference to the accompanying drawings. Specifically shown herein are:

[0070] Figure 1 Schematic diagram of a laminate according to the prior art;

[0071] Figure 2 Schematic diagram of a laminate according to the present invention according to a first embodiment;

[0072] Figure 3 Schematic diagram of a laminate having a separately shown printed layer according to Figure 2 ;

[0073] Figure 4 Schematic diagram of a laminate according to the present invention according to a second embodiment;

[0074] Figure 5 Schematic diagram of a laminate according to the present invention according to a third embodiment;

[0075] Figure 6 Schematic diagram of a laminate according to the present invention having different outer layers according to Figure 4 ;

[0076] Figure 7 Laminates according to the invention with different outer layers Figure 5 Schematic view of a laminate according to the invention;

[0077] Figure 8 Schematic view of the film layers of a second blown film (i.e., inner blown film) according to an embodiment of the invention; and

[0078] Figure 9 Schematic view of the film layers of a second blown film (i.e., inner blown film) according to another embodiment of the invention. Detailed description of the invention

[0079] In the following description, the same reference numerals are used for components having the same and similar functions.

[0080] Figure 1 Schematic view of a laminate according to the prior art, in which a transparent film 20 made of oriented polyethylene terephthalate with a layer thickness of 12 μm is printed using a reverse printing process (i.e., from the back), i.e., provided with a design. As has been customary in the prior art to date, an adhesive layer 40 with an application weight of 3 g / m 2 is applied to the printed layer 30, which in turn requires a sealing layer 50 with a thickness greater than 120 μm to 140 μm to be bonded to the printed layer 30. According to the prior art, in these laminates, during the production of packaging, in particular tubular bag packaging, the very thick sealing layer 50 is fused (i.e., sealed) with the equally thick sealing layer 50 of a second laminate blank of a corresponding structure by melting the surfaces of the two sealing layers 50 facing each other at the back, or, if necessary, with a part of the folded portion of the same laminate, which is why the sealing layer 50 according to the prior art is not oriented (i.e., not stretched) in order to maintain the sealing property.

[0081] Figure 2 Schematic view of a laminate 10 according to the invention according to a first embodiment, in which the outer layer 15 is coated with a first laminate layer 60 (which represents a first external extrusion laminate layer) during a single extrusion lamination process, and at the same time is coated with a first outer blown film 70 (which represents or has a low-temperature sealing layer 78).

[0082] Figure 3 Schematic view of a laminate 10 with a separately shown printed layer Figure 2 wherein the laminate 10 according to Figure 3 corresponds to the laminate 10 according to the invention according to Figure 2 but shows the outer layer 15 in more detail, namely in the form of a transparent film 20 provided with a reverse printed layer 30. Here, the transparent film 20 and the printed layer 30 together form the outer layer 15.

[0083] Figure 4 Shows a schematic view of the laminate 10 according to the invention according to a second embodiment, wherein the laminate 10 is identical in its layer sequence to the laminate 10 according to Figure 3 , except that the second inner extrusion laminate layer 65 and the second inner blown film 75 are arranged in a sandwich-like manner between the outer layer 15 and the first outer extrusion laminate layer 60. As already shown in Figure 3 , also in the exemplary embodiment according to Figure 4 , the first outer blown film 70 is a low-temperature sealing layer 78 with a thickness of only 40 μm.

[0084] Thus, the layer structure of the laminate 10 according to the invention according to Figure 4 is produced from a transparent film 20 which is provided with a printed matter 30 from the back during the reverse printing process, and the printed matter 30 is then coated simultaneously with the following layers in the following order during the tandem extrusion lamination process, looking from the outer layer 15 in the direction towards the sealing layer 50: The second inner extrusion laminate layer 65 with an application weight of 20 g / m 2 / The second inner blown film 75 made of LLDPE with a layer thickness of 40 μm / The first outer extrusion laminate layer 60 with an application weight of 20 g / m 2 / The first outer blown film 70 made of LLDPE with a layer thickness of 40 μm. If necessary, the second inner blown film 75 can have a terpolymer layer 120 facing the printed layer 30, as Figure 9 exemplarily shown.

[0085] According to Figure 4 , an example of the specific layer structure of the laminate 10 according to the invention can be the following layer sequence:

[0086] Example 1:

[0087] Transparent film 20 (i.e., oriented polyethylene terephthalate with a layer thickness of 12 μm) / Reverse printed layer 30 (e.g., as an engraved or aniline printed layer) / Second inner extrusion laminate layer 65 (i.e., polyethylene with an application weight of 20 g / m 2 ) / Second inner blown film 75 (i.e., LLDPE film with a layer thickness of 40 μm) / First outer extrusion laminate layer 60 (i.e., polyethylene with an application weight of 20 g / m 2 ) / First outer blown film 70 (i.e., LLDPE film with a layer thickness of 40 μm as the low-temperature sealing layer 78).

[0088] Example 2:

[0089] Transparent film 20 (i.e., biaxially oriented polypropylene with a layer thickness of 20 μm) / Reverse printing layer 30 (e.g., as an engraved or aniline printing layer) / Second inner extrusion laminating layer 65 (i.e., polyethylene with an application weight of 20 g / m 2 of polyethylene / Second inner blown film 75 (i.e., LLDPE film with a layer thickness of 40 μm) / First outer extrusion laminating layer 60 (i.e., polyethylene with an application weight of 20 g / m 2 of polyethylene) / First outer blown film 70 (i.e., LLDPE film with a layer thickness of 40 μm serving as the low-temperature sealing layer 78).

[0090] Example 3:

[0091] Transparent film 20 (i.e., polyethylene stretched or oriented at a ratio of 1:5 in the machine direction and with a layer thickness of 20 μm) / Reverse printing layer 30 (e.g., as an engraved or aniline printing layer) / Second inner extrusion laminating layer 65 (i.e., polyethylene with an application weight of 20 g / m 2 of polyethylene / Second inner blown film 75 (i.e., LLDPE film with a layer thickness of 40 μm) / First outer extrusion laminating layer 60 (i.e., polyethylene with an application weight of 20 g / m 2 of polyethylene) / First outer blown film 70 (i.e., LLDPE film with a layer thickness of 40 μm serving as the low-temperature sealing layer 78).

[0092] Example 4 has improved water vapor and gas (and especially oxygen and carbon dioxide) impermeability:

[0093] Transparent film 20 (i.e., oriented polyethylene terephthalate with a layer thickness of 12 μm) / Reverse printing layer 30 (e.g., as an engraved or aniline printing layer) / Second inner extrusion laminating layer 65 (i.e., polyethylene with an application weight of g / m 2 of polyethylene) / Second inner blown film 75 (i.e., LLDP stretched or oriented at a ratio of 1:1.6 in the machine direction and with a layer thickness of 30 μm) / First outer extrusion laminating layer 60 (i.e., polyethylene with an application weight of 20 g / m 2 of polyethylene) / First outer blown film 70 (i.e., LLDPE film with a layer thickness of 40 μm serving as the low-temperature sealing layer 78).

[0094] Example 5 has improved water vapor and gas (and especially oxygen and carbon dioxide) impermeability:

[0095] Transparent film 20 (i.e., polyethylene stretched or oriented at a ratio of 1:5 in the machine direction and with a layer thickness of 20 μm) / Reverse printing layer 30 (e.g., as an engraved or aniline printing layer) / Second inner extrusion laminating layer 65 (i.e., polyethylene with an application weight of 20 g / m 2Polyethylene) / second inner blown film 75 (i.e., LLDPE film stretched in the machine direction with a stretching or orientation ratio of 1:1.6 and a layer thickness of 30 μm) / first outer extruded laminate layer 60 (i.e., an application weight of 20 g / m 2 Polyethylene) / first outer blown film 70 (ie, LLDPE film with a layer thickness of 40 μm as the low-temperature sealing layer 78).

[0096] According to Examples 4 and 5, the water vapor and gas barrier layer of the laminate 10 according to the invention is improved in a very advantageous manner by using a LLDPE film stretched uniaxially in the machine direction, which film has been stretched to a layer thickness of 30 μm with a stretch ratio of 1:1.6.

[0097] In particular, Examples 3 and 5 described above represent particularly preferred embodiments according to the present invention, as their recyclability is particularly advantageous due to the substantially single-material structure of the laminate 10 described.

[0098] With the laminate 10 according to the invention, in particular according to Examples 1 to 5, very strong tubular bags, in particular also with an upright bottom, can be produced for packaging volumes of up to 10 kg or more, which are particularly suitable for packaging goods that must remain dry. Such packages have excellent impermeability to water vapor and gases, in particular oxygen and carbon dioxide, and high sealing strength, as demonstrated by drop tests of filled packages from heights of up to two meters.

[0099] Figure 5 A schematic diagram of a laminate 10 according to the invention is shown according to a third embodiment, wherein Figure 5 The laminate 10 corresponds substantially to Figure 4 The laminate 10 of 10 is different in that a metallized barrier layer 80 made of aluminum oxide is introduced between the second inner extruded laminate layer 65 and the second inner blown film 75, which in turn has a layer thickness in the range of 3 μm to 5 μm. In order to improve the adhesion of the barrier layer 80, the second inner blown film 75 has a terpolymer layer 120 facing the barrier layer 80, however, in Figure 5 In, as in Figure 4 As in the example, the terpolymer layer is not shown.

[0100] Figure 6 and Figure 7 They are shown according to Figure 4 and Figure 5 Schematic diagram of laminates 10 according to the invention, wherein their outer layers 15 have different Figure 4 and Figure 5 The structure shown.

[0101] Therefore, according to Figure 6 andFigure 7 The outer layer 15 does not represent the transparent film with the printing layer 30 provided during the reverse printing process as shown in Figure 4 and Figure 5 Rather, it is the non - transparent film 25 with the printed part 35 provided during the front - side printing process. Therefore, the printed part 35 is not adjacent to the second inner extrusion laminate layer 65, but is on the outer visible surface of the laminate 10 according to the present invention. Similarly, the non - transparent film 25 thus represents the layer of the laminate 10 according to the present invention that is adjacent to the second inner extrusion laminate layer 65.

[0102] Two Figure 8 and Figure 9 show a detailed view of the second inner blow - molded film 75, which Figure 8 is six - layer and Figure 9 is seven - layer according to Figure 8 The six - layer structure of the second inner blow - molded film 75 according to

[0103]

[0104] Figure 9 As described above, the second inner blow - molded film 75 according to Figure 9 differs from the second inner blow - molded film 75 according to Figure 8 in that, according to Figure 9The second inner blown film 75 has an additional terpolymer layer 120 on the outer side of the first HDPE layer 90, which in the overall composite of the laminate 10 according to the invention faces the direction of the outer layer 15 and is used to improve the bonding between the layers and, together with the aforementioned layer of the second inner blown film 75, is simultaneously incorporated into the second inner blown film 75 as the outermost layer 120 during the blow molding process. According to the invention, the thickness of the terpolymer layer 120 also lies in the range between 1 μm and 5 μm, preferably between 1.5 μm and 4 μm, and particularly preferably between 2 μm and 3 μm.

[0105] It should also be noted that the structure of the first outer blown film 70 can be similar to that of the second inner blown film 75, but can also have a different, for example single-layer structure, and can for example consist only of a low-temperature sealing layer 78 containing LLDPE, where the low-temperature sealing layer 78 and thus the entire first outer blown film 70 have a layer thickness in the range between 4 μm and 20 μm in this case. Furthermore, it should be noted that if, for example, an opaque layer and / or another barrier layer are to be incorporated into the first blown film 70 and / or the second blown film 75, both the first outer blown film 70 and the second inner blown film 75 can contain a color pigment (such as titanium dioxide) and / or a metal layer.

[0106] In this regard, it should be noted that all of the above parts, especially the details shown in the drawings, are considered to be essential to the invention when observed individually and in any combination. Modifications thereof are familiar to those skilled in the art.

[0107] List of reference numerals

[0108] 10 Laminate

[0109] 15 Outer layer

[0110] 20 Transparent film

[0111] 25 Opaque film

[0112] 30 Print / printing layer (reverse print)

[0113] 35 Print (front print)

[0114] 40 Adhesive layer

[0115] 50 Sealing layer

[0116] 60 First extrusion laminate layer / first outer extrusion laminate layer

[0117] 65 Second extrusion laminate layer / second inner extrusion laminate layer

[0118] 70 First (outer) blown film

[0119] 75 Second (Inner) Blown Film

[0120] 78 Low Temperature Sealing Layer

[0121] 80 Barrier Layer (Metallized)

[0122] 90 HDPE Layer

[0123] 100 Primer

[0124] 110 Gas Barrier Layer

[0125] 120 Terpolymer Layer

Claims

1. A laminate (10), in particular a laminate for producing a packaging piece, the laminate having an outer layer (15) which may optionally have a design and a sealing layer (50) arranged opposite the visible side of the outer layer (15). Characterized in that the sealing layer (50) is preferably a low-temperature sealing layer (78), wherein the sealing layer (50) is designed as the outermost layer of a first blown film (70) or is designed as a first blown film (70); and a first extrusion laminating layer (60) is arranged between the outer layer (15) and the blown film (70).

2. The laminate according to claim 1, Characterized in that a second extrusion laminating layer (65) facing the outer layer (15), in particular directly adjacent to the outer layer (15), exists between the first extrusion laminating layer (60) and the outer layer (15), and a second blown film (75) bonded to the second extrusion laminating layer (65), wherein the second blown film (75) is bonded to the first extrusion laminating layer (60).

3. The laminate according to any one of the preceding claims, in particular according to claim 2, Characterized in that the first blown film (70) and / or the second blown film (75) consists of a plurality of blown film layers, the blown film layers being preferably stretched, in particular stretched in the machine direction and / or in the transverse direction of the machine direction, and the first blown film (70) and / or the second blown film (75) each define a layer of the laminate as a whole.

4. The laminate according to any one of the preceding claims, in particular according to claims 2 to 3, Characterized in that the first blown film (70) and / or preferably the second blown film (75) has at least one barrier layer material.

5. The laminate according to claim 4, Characterized in that the barrier layer material is selected from stretched high-density polyethylene (HDPE), ethylene-vinyl alcohol copolymer (EVOH) and / or polyamide.

6. The laminate according to any one of the preceding claims, in particular according to claims 2 to 5, Characterized in that the laminate (10) has at least one additional barrier layer (80), the at least one additional barrier layer being in the form of a metallized layer, an alumina and / or silica layer, or a metal layer, in particular in the form of aluminum or an aluminum combination, the at least one additional barrier layer being arranged adjacent to the first blown film (70) and / or preferably adjacent to the second blown film (75), particularly preferably arranged on the side of the second blown film (75) facing the outer layer (15).

7. The laminate according to any one of the preceding claims, in particular according to claims 2 to 6, Characterized in that the first blown film (70) and / or the second blown film (75) has an outermost layer made of a terpolymer (120), in particular a mixture based on ethylene, acrylic acid and acrylate.

8. The laminate according to any one of the preceding claims, in particular according to claims 2 to 7, Characterized in that The first blown film (70) and / or the second blown film (75) contains titanium dioxide.

9. The laminate according to any one of the preceding claims, characterized in that the outer layer (15) is selected from a transparent film (20) or an opaque film and, if necessary, a printed matter forming the design of the outer layer (15), wherein the printed matter is designed as a reverse print (30) or a front print (35) in the case of a transparent film (20), and as a front print (35) in the case of an opaque film (20).

10. The laminate according to any one of the preceding claims, in particular according to claims 2 to 9, characterized in that the material of the transparent film (20) is polyethylene terephthalate, in particular oriented polyethylene terephthalate, or polyolefin, in particular biaxially oriented polypropylene or polyethylene in the machine direction.

11. The laminate according to any one of the preceding claims, in particular according to claims 2 to 10, characterized in that the first blown film (70) and / or the second blown film (75) contains low density polyethylene, in particular LLDPE, as a material providing stability.

12. The laminate according to any one of the preceding claims, in particular according to claims 2 to 11, characterized in that the second blown film (75) is a composite of the following layers: terpolymer / HDPE / primer / EVOH / primer / HDPE / LLDPE or metallocene.

13. The laminate according to any one of the preceding claims, in particular according to claims 2 to 12, characterized in that the layers of the laminate have the following thicknesses or application weights:

14. The laminate according to any one of the preceding claims, in particular according to claims 2 to 13, characterized in that the laminate (10) has a polyolefin content of more than 90%, preferably more than 95%, in particular a polyethylene content of more than 90%, preferably more than 95%.

15. The laminate according to any one of the preceding claims, in particular according to claims 2 to 14, characterized in that the laminate (10) is produced by extrusion lamination, in particular by tandem extrusion lamination.

16. Use of the laminate (10) according to any one of the preceding claims for producing a packaging, in particular a tubular bag packaging, in particular a tubular bag packaging capable of standing upright.

17. A packaging produced from the laminate (10) according to any one of claims 1 to 15 preceding.

18. A method for producing a laminate according to any one of claims 1 to 15 preceding, characterized in that the following steps are carried out: - providing an outer film (15); - during a single extrusion lamination, coating the outer film (15) with a primer (100) and a first extrusion lamination layer (60) and a first blown film (70) arranged on the other side of the first extrusion lamination layer (60) if necessary; or - providing an outer film (15); - If necessary, during the tandem extrusion lamination process, the outer film (15) is coated using a primer (100), a second inner extrusion lamination layer (65), a second blown film (75) disposed on the other side of the second extrusion lamination layer (65), a first extrusion lamination layer (60) disposed on the other side of the second blown film (75), and a first blown film (70) disposed on the other side of the first extrusion lamination layer (60).

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