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

Technical Field

[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. Existing technology

[0002] Laminates for producing packages, such as tubular bags with or without a vertical bottom, are already known. According to the prior art, such laminates usually consist of a printable outer layer and a sealing layer, which is usually attached to the outer layer by means of an adhesive. To produce the package, two separate blanks of the laminate are sealed together using the sealing layers of the individual blanks, which face each other along the outer edges of the blanks, 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 together by a seal, a single blank can be used, which is folded so that the outer edges of the folded blanks 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 sealing between two blanks or folded blanks is always performed by pressing a sealing clamp onto the outer side of the respective outer layer adjacent to the sealing layer, the sealing clamp having a high temperature that softens the two sealing layers to be sealed together, so that the respective polymer chains of the respective sealing media can fuse together, thereby ensuring a tight seal and therefore a reliable closure of the package.

[0003] A disadvantage of such laminates used for the production of such packages is that the respective sealing layer, which also imparts stability to the package, is very thick. Consequently, taking into account the fact that conventional polymers used for sealing layers (such as polyethylene or polypropylene) are not good thermal conductors, the transfer of the thermal energy required to melt the surface to be sealed to the surface to be sealed is problematic, since the heat transfer from the sealing jig must first pass through the outer layer of the respective 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 occur, owing to the fact that its surface to be sealed is located on the opposite side from the heat introduced. However, since the sealing layers used to date according to the prior art have a very high thickness (i.e., a thickness in the range of greater than 50 μm, but typically even in the range of 100 to 140 μm), in order to ensure a good and tight seal, a very high heat input is necessary, 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 respective outer layer of the laminate.

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

[0005] Alternatively, as mentioned above, the dwell time of the sealing jaws on the respective outer layer of the laminate can also be extended. Depending on the material used, there is no risk of denaturation of the outer layer if it is not completely melted due to the long dwell time. However, due to the necessary long dwell time of the sealing jaws on the respective outer layer of the laminate, the production speed is significantly reduced, which in turn can have a very negative impact on the productivity during the production of the packages and on the sealing of the packages after filling.

[0006] Furthermore, both alternatives (i.e., increasing the temperature of the sealing jaws and extending the dwell time of the sealing jaws on the outer layer of the laminate) also lead to an undesirable increase in the cost of producing the packages and, therefore, also to an increase in the overall cost of the packaged product. Of course, another factor that further increases the cost of producing packages using previously known laminates is that, due to the high thickness of the sealing layer of these laminates (which has been necessary until now), the material requirements for the sealing medium are very high, which in turn is disadvantageous due to the cost of the sealing medium.

[0007] Further disadvantages of the laminates of the front line are poor chemical resistance due to the necessary use of adhesives, the typical low bond / adhesion strength of extrusion laminated thick (>50 μm) cast LLDPE and polypropylene films and polypropylene blown films, which also shows up in poor drop tests. Summary of the Invention

[0008] The present invention is based on the purpose that a kind of alternative, cost-effective laminate is provided, and this laminate is suitable for producing packaging and avoids the above-mentioned disadvantages.In addition, the object of the present invention is also to be able to use this laminate to produce packaging and to provide the packaging produced by this laminate.

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

[0010] In particular, the objects of the present invention are achieved by a laminate, in particular for producing packaging, comprising an outer layer which may have a design and a sealing layer arranged opposite a visible face of the outer layer, wherein the sealing layer is preferably a low-temperature sealing layer, which is formed as a first blown film or the outermost layer of the first blown film, and a first extrusion laminate layer is arranged between the outer layer and the blown film.

[0011] The core of the invention is that, according to the invention, the sealing layer is designed as a low-temperature sealing layer. In this context, the term "low-temperature sealing layer" means that the sealing layer according to the 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) or as the outermost layer of a multi-layer blown film. The main advantage of a blown film used as a low-temperature sealing layer or outermost layer of a blown film is that the material thickness of the sealing layer according to the 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, i.e., almost spontaneously, unlike the prior art, in which the sealing layer thickness is in the range of more than 50 μm, but mostly even in the range of 100 μm to 140 μm, a large amount of sealing medium must first be heated in order to reach the initial sealing temperature also on the outermost side of the laminate facing the visible side of the laminate.

[0012] In the context of the present invention, the initial sealing temperature is understood to be the temperature at which the outer surface of the sealing layer melts, so that fusion of this outer surface of the sealing layer with the counterpart to be sealed is possible.

[0013] Another major advantage of the present invention is that the laminate according to the present invention comprises a first extruded laminate layer between the outer layer and the blown film. This allows the outer layer to be bonded to the blown film without the use of adhesives. The laminate according to the present invention is thus formed during an extrusion lamination process, wherein the extruded laminate layer is introduced in a molten state between the outer layer and the blown film. This allows for an optimal bond between the outer layer and the blown film. By introducing the extruded laminate layer in a molten state between the outer layer and the blown film, an intimate, almost optimal thermal contact is established between the outer layer and the blown film, resulting in virtually unimpeded heat transfer from the outer layer to the surface of the sealing layer, occurring very quickly, i.e., within a range of a few milliseconds to approximately 50 milliseconds, i.e., almost spontaneously.

[0014] According to one embodiment of the present invention, a second extruded laminate layer facing the outer layer, in particular a second extruded laminate layer arranged next to the outer layer, and a second blown film bonded to the second extruded laminate layer are arranged between the first extruded laminate layer and the outer layer, wherein the second blown film is bonded to the first extruded laminate layer.

[0015] According to this embodiment, the above-mentioned basic laminate according to the invention is extended in a sandwich-like manner by a second extruded laminate layer and a second blown film adjacent thereto, wherein in this case the second extruded laminate layer forms a bonding layer to the outer layer, while the second blown film is a bonding layer to the first extruded laminate layer, to which the first blown film with its outer sealing layer is attached, as described above.

[0016] For the production of this embodiment of the invention, since the second extruded laminate layer is introduced into the layer composite of the laminate according to the invention by serial extrusion lamination, i.e. simultaneously with the first extruded laminate layer, there is a close bond between the individual 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 extruded laminate layer and the first blown film according to the invention, similar to double glazing or laminated glass in window panes, significantly improves the stability of the laminated structure, even if the combined thickness of the second blown film, the first extruded 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 which originally provides stability.

[0018] According to one embodiment of the present invention, the first blown film and / or the second blown film is made from a melt of the polymers 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 consists of a plurality of blown film layers, preferably stretched, in particular in the machine direction and / or in the transverse direction thereof. Furthermore, the first blown film and / or the second blown film each define a layer of the laminate in their entirety.

[0020] At this point, it should be noted that the term "stretching" of a film specifically refers to stretching the film below its 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 multilayer film, the polymer forming the multilayer film). By this stretching, the unoriented polymer present in the film is largely aligned in the stretching direction, whereby the stretching direction can be the machine direction and / or the transverse direction to the machine direction. By orienting the plastic film during stretching, in particular the stiffness, tensile strength and toughness of the film can be improved.

[0021] Thus, during the production of films by flat film extrusion or blown film extrusion (i.e. during the production of films from corresponding polymer melts), a specific orientation of the polymer molecules does not therefore explicitly constitute a stretching of the films produced by this process, as is also known, for example, from EP 4 076 944 B1.

[0022] According to the present invention, the first and second blown films can therefore have different functional layers and, therefore, different functionalities. To this end, both the first and second blown films are produced in blow molding units assigned to them. The first and second blown films can each have the same structure. Alternatively, however, the first and second blown films can also have different properties and different translucencies.

[0023] According to a preferred embodiment of the 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, so that the second inner blown film primarily contributes to the structural safety and rigidity and stability of the laminate according to the invention, while the first outer blown film can be thinner than the second inner blown film and is decisive for the very good sealing properties of the laminate according to the invention.

[0024] Thus, in an advantageous manner, the costs of producing the laminate according to the invention can be reduced by using only high-quality materials for the respective outer lamination layers, while the lamination layers enclosed in the laminate can be of lower quality, since their, for example, optical appearance is irrelevant to the laminate according to the invention, since they are not visible due to being enclosed between the outer lamination layers. However, it should be noted that any lower-quality inner lamination layers that may be used according to the invention still ensure very good bond strengths between the individual lamination 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 invention, the barrier layer material is selected from high-density polyethylene (HDPE), ethylene-vinyl alcohol copolymer (EVOH) and / or polyamide, which may be optionally stretched, in order to impart to the corresponding blown film and therefore also to the laminate according to the invention a high degree of gas impermeability on the one hand and also moisture and water vapor impermeability on the other hand.

[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 invention, the laminate according to the invention may have at least one further barrier layer in the form of a metallized layer, an aluminum oxide and / or silicon oxide layer, or a metal layer, in particular aluminum or an aluminum bond, 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 outer layer.

[0028] In the context of the present invention, with reference to EP 3 067 437 B1, the term "aluminum bonding" refers to a process in which aluminum metal is deposited on a surface (e.g. the first blown film and / or preferably the second blown film) in an oxygen-rich environment, so that on the surface of the blown film to be coated there is a aluminum oxide-aluminum metal-aluminum oxide (AlO x -Al-AlO x The metal layer is deposited in the form of a quasi-surrounded aluminum oxide layer. In this process, the surface of the blown film to be coated is exposed to oxygen both before and during metal deposition, so that an oxygen-rich metal oxide layer forms between the film surface and the deposited metal. This significantly improves the adhesion between the film surface and the aluminum-containing layer.

[0029] In a particularly advantageous manner, the laminate according to the invention has a water vapor permeability of less than 0.5 g / m² in an environment with a relative humidity of 85%. 2 / day, and when using a metallized barrier layer in combination with EVOH, it can even reach less than 0.1g / m 2 Similarly, the permeability of the laminate according to the present invention to oxygen can be reduced to less than 0.5 cm in an environment at a temperature of 23° C. and a relative humidity of 85%. 3 / m 2 / day, and even reduced to less than 0.2 cm when a metallized barrier layer is used in combination with EVOH 3 / m2 / day. Oxygen permeability measurements were performed according to DIN standard 53380-3. Water vapor permeability measurements were performed 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 consisting of a mixture of ethylene, acrylic acid and an acrylate. Preferably, the terpolymer is manufactured by The Dow Chemical Company Global Dow Center, 2211 H.H. Dow Way, Midland, Michigan 48674 (US) under the name "Nucrel TM A terpolymer sold under the name AE".

[0031] According to a preferred embodiment of the present invention, if the laminate according to the present invention is not formed in the form of a sandwich by a second extruded laminate layer and a second blown film, but is formed solely 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 manner described above, the laminate according to the present invention comprises a second extruded laminate layer and a second blown film in addition to the first extruded laminate layer and the first blown film, preferably, according to the present invention, only the second blown film comprises the terpolymer, in which case the terpolymer again forms the outermost layer of the second blown film. When a terpolymer is used, the outermost layer of the first or second blown film is understood to be the layer of the respective blown film that faces the outermost layer in the laminate.

[0032] According to the present invention, it has been found that by using the above-mentioned terpolymer based on ethylene, acrylic acid and acrylate as the outermost layer of a respective blown film facing the outer layer of the laminate, the adhesion between the blown film and the adjacent extruded laminate layer can be improved, whereby, when using such a terpolymer layer in the respective blown film, it is also possible to use a metallized barrier layer 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 comprises titanium dioxide.

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

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

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

[0037] Furthermore, the first blown film and / or the second blown film comprises low-density polyethylene, in particular LLDPE, as a material providing stability.

[0038] According to the present invention, the use of LLDPE as a material for blown films providing stability is particularly suitable, since LLDPE is a preferred material for producing thin blown films and, according to the present invention, it has been found to be a well-sealable material, which is also suitable for particularly thin layers, in particular layers bonded to one another, for producing very stable seals, as is required for the production of packages using the laminate according to the present invention. Furthermore, LLDPE is a plastic that is inexpensive to produce, recyclable, and harmless to health.

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

[0040] Advantageously, by using such a composite, high barrier laminates can be produced with very good impermeability values in terms of water vapor permeability and oxygen permeability, whereby the water vapor impermeability and oxygen impermeability can be further improved by stretching, in particular in the uniaxial direction (i.e. in the blowing direction), as has been found according to the present invention. In this context, it should be noted that the terms "stretching" or "stretched" and "orientation" or "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 the use of a thinner layer, which according to the present invention has a maximum thickness of 60 μm but is preferably thinner than or equal to 50 μm, instead of the thick sealing layers according to the prior art, which are always thicker than 50 μm and often even have a thickness in the range of 100 μm to 140 μm, for producing packages or sealing with themselves or with the same corresponding sealing layer. The use of such a thin layer according to the present invention is particularly relevant for the sealing layer used according to the present invention, which according to the present invention has only a fraction of the thickness and, therefore, also a fraction of the thermal capacity of the previously conventional layers and can therefore be sealed quickly, precisely, securely and safely in a particularly easy manner, with regard to the quality, precision and safety achievable according to the present invention, in particular without damaging the laminate layers closer to the sealing nip during the sealing process, which was not possible with previously thick sealing layers.

[0045] According to another particularly preferred embodiment of the invention, the laminate 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%.

[0046] This high polyolefin content, and preferably even polyethylene content, of the laminate according to the invention makes the recyclability of the laminate according to the invention particularly good and can be achieved according to the invention by using polyethylene, in particular stretched polyethylene, for the outer layer, which has particularly strong rigidity and particularly good printability. Furthermore, according to the invention, polyethylene is used for the first and second extruded laminate layers; the same applies to the production of the first and second blown films, which also include polyethylene as the main material providing stability, i.e. high-density polyethylene (in particular HDPE) or low-density polyethylene (in particular LLDPE).

[0047] Thus, according to the invention, in a particularly advantageous manner, substantially no materials other than polyethylene, such as adhesives, may be used, so that their proportion may be limited to less than 10%, preferably less than 5%, which optimizes the mechanical recyclability of the laminate according to the invention.

[0048] As mentioned 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 two or three basic functional layers of an outer layer and a first blown film or 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 contain functional materials, such as barrier layers or dyes or terpolymers.

[0049] As mentioned above, the object of the invention is also achieved by using the laminate according to the above for producing packages, in particular tubular bag packages, which packages are particularly capable of being erected.

[0050] Furthermore, the object of the present invention is also achieved by a package produced from the laminate according to the invention.

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

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

[0053] - Provide an outer membrane;

[0054] - coating the outer film with a primer, if necessary, and a first extrusion laminate layer and a first blown film arranged on the other side of said first extrusion laminate layer, in a single extrusion lamination process;

[0055] or

[0056] - Provide an outer membrane;

[0057] If necessary, the outer film is coated with a primer as well as a second inner extrusion laminate layer and a second blown film arranged on the other side of the second extrusion laminate layer, and a first extrusion laminate layer arranged on the other side of the second blown film and a first blown film arranged on the other side of the first extrusion laminate layer during a tandem extrusion lamination process.

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

[0059] The laminate according to the invention is suitable for flexible packaging, wherein the laminate is particularly suitable for winding into rolls and, above all, for producing bag packaging for all types of filled goods. According to the prior art, polyethylene adhesive films have hitherto been used for such packaging, in particular LLDPE film adhesives with a thickness significantly greater than 50 μm, typically 100 μm to 140 μm, for example with the following structure: oriented polyethylene terephthalate (OPET) with a thickness of 12 μm / printing layer / primer / LLDPE film adhesive >50 μm has been used.

[0060] The laminate according to the invention is produced by single extrusion lamination or tandem extrusion lamination, for example a laminate having the following layer structure can be produced: oriented polyethylene terephthalate (OPET) with a thickness of 12 μm / printing layer / primer / second extrusion lamination layer, i.e. polyethylene with an application weight of 20 g / m 2 Inner extruded laminate layer / second blown film, i.e. inner blown film made of linear low density polyethylene, in particular LLDPE or consisting essentially of it, with a total blown film thickness of 40 μm / first extruded laminate layer, i.e. polyethylene with an applied weight of 20 g / m 2 The outer extrusion laminate layer / first blown film, ie the outer blown film made of or essentially consisting of linear low density polyethylene, in particular LLDPE, has a total blown film thickness of 40 μm.

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

[0062] Furthermore, due to the absence of adhesives in the laminates according to the invention, the laminates according to the invention exhibit a guaranteed high bond strength, excellent chemical resistance, and significant cost advantages, since the laminates according to the invention do not require curing time during production. Also, since no adhesive is used during production, the production process is more cost-effective due to blown film and single or tandem extrusion technologies, especially since, according to the invention, inexpensive resins are used for the interlayer LLDPE film. According to the invention, the sealing layer at the joint between the laminate layers can be produced during the production of packages that are significantly thinner than in the prior art and, most importantly, can be produced at lower temperatures and, therefore, more quickly, thereby achieving significantly better package value (added value) compared to the adhesive laminations known to date from the prior art.

[0063] Furthermore, the novel laminates according to the invention provide better "drop test" results compared to currently known bonded laminates in the prior art and to laminates known in the prior art using thick (i.e. at least 50 μm but typically 100 μm to 140 μm thick) LLDPE sealing films.

[0064] The laminate according to the invention thus has the advantage that it can be produced by single or tandem extrusion lamination of printed or printable films, which can consist of a variety of materials, such as oriented polyethylene terephthalate (OPET), biaxially oriented polypropylene (BOPP), oriented polyamide (OPA), low uniaxially oriented polyethylene (MDO-PE), whereby a very thin layer of primer is applied over the entire printed surface. The coating weight of the solvent-based primer or preferably the water-based primer is between 0.2 g / m 2 Up to 2g / m 2 In the range of 0.3 g / m 2 Up to 1g / m 2 In the range of, and particularly preferably between 0.4 g / m 2 Up to 0.6g / m 2 In the range of , this corresponds, according to the invention, to a layer thickness 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 aforementioned further layers are applied simultaneously in the aforementioned single or tandem extrusion lamination process, i.e. the polyethylene application weight is preferably 20 g / m 2 ±5g / m 2 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 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] The main advantage of the present invention is therefore that the expensive problem of adhesive lamination of thick (>50 μm) LLDPE films to printed substrates, which has been used until now, can be overcome by applying to the printed substrate a single or tandem extrusion composite, in the case of a single extrusion, of a thin (<50 μm) LLDPE film and an extruded polyethylene coating, or in the case of a tandem extrusion, of two thin (<50 μm) LLDPE films and two extruded polyethylene coatings in a sandwich-like structure, which printed substrate can also be unprinted.

[0066] Furthermore, with the present invention, the previously always very low adhesion strength of extrusion laminated thick (>50 μm) LLDPE films can be overcome by using a thin (<50 μm) LLDPE film according to the present invention together with the aforementioned extrusion coating, wherein, in the case of using a tandem extrusion device, two or, in the case of an extrusion device extending beyond the tandem extrusion device, a plurality of thin (<50 μm) LLDPE films together with their respective extruded polyethylene coatings applied to a support film, such as a printed substrate.

[0067] In this way, it is possible in an advantageous manner to obtain a monolayer or tandem extruded thin (<50 μm) LLDPE film instead of an adhesive laminated thick (>50 μm) LLDPE film.

[0068] Further embodiments of the invention are apparent from the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The present invention will now be described by way of exemplary embodiments, which will be explained in more detail with reference to the accompanying drawings.

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

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

[0072] Figure 3 With a printed layer shown separately Figure 2 a schematic diagram of a laminate;

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

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

[0075] Figure 6 With different outer layers Figure 4 A schematic diagram of a laminate according to the present invention;

[0076] Figure 7 With different outer layers Figure 5 A schematic diagram of a laminate according to the present invention;

[0077] Figure 8 A schematic diagram of film layers of a second blown film (ie, an inner blown film) according to an embodiment of the present invention; and

[0078] Figure 9 Schematic diagram of film layers of a second blown film (ie, inner blown film) according to another embodiment of the present invention. DETAILED DESCRIPTION

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

[0080] Figure 1 A schematic diagram of a laminate according to the prior art is shown, 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 (ie from the back), i.e. provided with a design. As has been customary in the prior art to date, a film having a thickness of 3 g / m 2 An adhesive layer 40 of application weight is applied to the printed layer 30, which in turn requires a sealing layer 50 having a thickness of 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 packages, in particular tubular bag packages, the very thick sealing layer 50 is fused (i.e., sealed) with a similarly thick sealing layer 50 of a second laminate blank of corresponding structure by melting the surfaces of the two sealing layers 50 facing each other at the rear, or, if necessary, with a portion 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 properties.

[0081] Figure 2 A schematic diagram of a laminate 10 according to the present invention according to a first embodiment is shown, wherein 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 is simultaneously coated with a first external blown film 70 (which represents or has a low-temperature sealing layer 78).

[0082] Figure 3 Shown with a printed layer shown separately according to Figure 2 A schematic diagram of a laminate 10, wherein according to Figure 3 The laminate 10 corresponds to Figure 2 The laminate 10 according to the invention is shown in FIG. 1 , but with the outer layer 15 shown 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 constitute the outer layer 15.

[0083] Figure 4 A schematic diagram of a laminate 10 according to the invention is shown according to a second embodiment, wherein the laminate 10 is identical with the laminate according to the invention in terms of its layer sequence. Figure 3 The laminate 10 is identical to the laminate 10 of FIG. 1 , except that the second inner extruded laminate layer 65 and the second inner blown film 75 are arranged in a sandwiched manner between the outer layer 15 and the first outer extruded laminate layer 60. As already described Figure 3 As shown in Figure 4 In the exemplary embodiment of FIG. 5 , the first outer blown film 70 is a low-temperature sealing layer 78 that is only 40 μm thick.

[0084] Therefore, according to Figure 4 The layer structure of the laminate 10 according to the invention is produced from a transparent film 20 which is provided with a print 30 from behind in a reverse printing process, which in turn is applied simultaneously with the following layers in the following order in a tandem extrusion lamination process, seen from the outer layer 15 in the direction towards the sealing layer 50: application weight 20 g / m 2 Second inner extruded laminate layer 65 / second inner blown film 75 made of LLDPE with a layer thickness of 40 μm / application weight of 20 g / m 2 The first outer extruded laminate layer 60 / the first outer blown film 70 made of LLDPE with a layer thickness of 40 μm. If necessary, the second inner blown film 75 may have a terpolymer layer 120 facing the printing layer 30, such as Figure 9 It is shown as an example in FIG.

[0085] according to Figure 4 An example of a specific layer structure of the laminate 10 according to the invention may be the following layer sequence:

[0086] Example 1:

[0087] Transparent film 20 (ie oriented polyethylene terephthalate with a layer thickness of 12 μm) / reverse printing layer 30 (eg as an engraved or flexographic printing layer) / second inner extrusion laminate layer 65 (ie with an application weight of 20 g / m 2 Polyethylene / second inner blown film 75 (ie, LLDPE film with a layer thickness of 40 μm) / first outer extrusion laminate layer 60 (ie, 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).

[0088] Example 2:

[0089] Transparent film 20 (ie biaxially oriented polypropylene with a layer thickness of 20 μm) / reverse printing layer 30 (eg as an engraved or flexographic printing layer) / second inner extrusion laminate layer 65 (ie with an application weight of 20 g / m 2 Polyethylene / second inner blown film 75 (ie, LLDPE film with a layer thickness of 40 μm) / first outer extrusion laminate layer 60 (ie, 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).

[0090] Example 3:

[0091] Transparent film 20 (i.e. polyethylene stretched in machine direction with a stretch or orientation ratio of 1:5 and a layer thickness of 20 μm) / reverse printing layer 30 (e.g. as an engraved or flexographic printing layer) / second inner extrusion laminate layer 65 (i.e. polyethylene with an application weight of 20 g / m 2 Polyethylene / second inner blown film 75 (ie, LLDPE film with a layer thickness of 40 μm) / first outer extrusion laminate layer 60 (ie, 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).

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

[0093] Transparent film 20 (ie oriented polyethylene terephthalate with a layer thickness of 12 μm) / reverse printing layer 30 (eg as an engraved or flexographic printing layer) / second inner extrusion laminate layer 65 (ie with an application weight of g / m 2 ) / second inner blown film 75 (ie, LLDP stretched in the machine direction with a stretch or orientation ratio of 1:1.6 and a layer thickness of 30 μm) / first outer extruded laminate layer 60 (ie, with 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).

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

[0095] Transparent film 20 (i.e. polyethylene stretched in machine direction with a stretch or orientation ratio of 1:5 and a layer thickness of 20 μm) / reverse printing layer 30 (e.g. as an engraved or flexographic printing layer) / second inner extrusion laminate layer 65 (i.e. polyethylene with an application weight of 20 g / m 2Polyethylene) / second inner blown film 75 (ie, 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 (ie, with 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 an 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] The laminate 10 according to the invention, in particular according to Examples 1 to 5, makes it possible to produce very strong tubular bags, in particular also with an upright bottom, 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 seal strength, as demonstrated by drop tests on 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 FIG. 1 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 FIG, the terpolymer layer is not shown.

[0100] Figure 6 and Figure 7 Shown respectively 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 and Figure 7 The outer layer 15 does not represent Figure 4 and Figure 5 The transparent film shown is provided with the print layer 30 during the reverse printing process, while the non-transparent film 25 is provided with the print 35 during the front printing process. Therefore, the print 35 is not adjacent to the second inner extruded laminate layer 65, but is on the outer visible side of the laminate 10 according to the present invention. Similarly, the non-transparent film 25 therefore represents the layer of the laminate 10 according to the present invention adjacent to the second inner extruded laminate layer 65.

[0102] two Figure 8 and Figure 9 A detailed view of the second inner blown film 75 is shown, which is Figure 8 It is six-layer and according to Figure 9 It is seven-story. Figure 8 The six-layer structure of the second inner blown film 75 includes a high-density polyethylene layer (i.e., HDPE layer 90), a primer layer 100, an adjacent gas barrier layer 110 made of EVOH or polyamide, and another primer layer 100 and a second HDPE layer 90 adjacent to the primer layer 100. Adjacent to the HDPE layer 90 is a low-temperature sealing layer 78 in the form of a thin LLDPE layer.

[0103] The thickness of each layer of the second inner blown film 75 blown in a single pass ranges from 4 μm to 20 μm for the HDPE layer 90 and also from 4 μm to 20 μm for the low-temperature sealing layer 78. The remaining layers of the second inner blown film 75 (i.e., the primer layer 100, the gas barrier layer 110 adjacent thereto, the second primer layer 100 adjacent to the gas barrier layer 110, and the HDPE layer 90 adjacent to the primer layer 100) have a total layer thickness in the range of 32 μm to 100 μm, with the primer layer having a 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 thickness of the gas barrier layer 110, preferably the EVOH layer, ranges from 1 μm to 5 μm, preferably in the range of 1.5 μm to 4 μm, and particularly preferably in the range of 2 μm to 3 μm. The thickness of the HDPE layer facing the low-temperature sealing layer 78 is obtained by subtracting the layer thickness of the primer layer 100 and the layer thickness of the gas barrier layer 110 from the total layer thickness in the range of 32 μm to 100 μm.

[0104] As mentioned above, according to Figure 9 The second inner blown film 75 is formed according to Figure 8 The second inner blown film 75 is different 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 faces the direction of the outer layer 15 in the overall composite material of the laminate 10 according to the present invention, serves to improve the bonding between the layers, and is simultaneously bonded to the second inner blown film 75 as the outermost layer 120 during the blowing process together with the aforementioned layers of the second inner blown film 75. According to the present invention, the thickness of the terpolymer layer 120 is also in the range of 1 μm to 5 μm, preferably in the range of 1.5 μm to 4 μm, and particularly preferably in the range of 2 μm to 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 structure, for example a single layer, and can, for example, consist solely of a low-temperature sealing layer 78 comprising LLDPE, wherein the low-temperature sealing layer 78, and therefore the entire first outer blown film 70, in this case has a layer thickness in the range of 4 μm to 20 μm. Furthermore, it should be noted that both the first outer blown film 70 and the second inner blown film 75 can contain color pigments (e.g., titanium dioxide) and / or metal layers if, for example, a non-transparent layer and / or another barrier layer is to be incorporated into the first blown film 70 and / or the second blown film 75.

[0106] At this point it should be noted that all of the above parts, particularly the details shown in the accompanying drawings, are considered essential to the invention when viewed individually and in any combination, and modifications thereof will be familiar to those skilled in the art.

[0107] Reference Signs List

[0108] 10 Laminates

[0109] 15 outer layer

[0110] 20 transparent film

[0111] 25 non-transparent film

[0112] 30 printed pieces / printing layer (reverse printed piece)

[0113] 35 printed parts (front printed parts)

[0114] 40 Adhesive layer

[0115] 50 sealing layer

[0116] 60 first extruded laminate layer / first outer extruded 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 (metallization)

[0122] 90HDPE layer

[0123] 100 Primer

[0124] 110 gas barrier layer

[0125] 120 terpolymer layer

Claims

1. A laminate (10), in particular for producing packaging, comprising an outer layer (15), optionally with a design, and a sealing layer (50) arranged opposite a visible face of the outer layer (15), It is characterized by: The sealing layer (50) is preferably 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); and A first extrusion laminate layer (60) is arranged between the outer layer (15) and the blown film (70).

2. The laminate according to claim 1, It is characterized by: Between the first extruded laminate layer (60) and the outer layer (15), there is a second extruded laminate layer (65) facing the outer layer (15), in particular directly adjacent to the outer layer (15), and a second blown film (75) bonded to the second extruded laminate layer (65), wherein the second blown film (75) is bonded to the first extruded laminate layer (60).

3. The laminate according to any one of the preceding claims, in particular according to claim 2, It is characterized by: The first blown film (70) and / or the second blown film (75) consists of a plurality of blown film layers, is preferably stretched, and the first blown film (70) and / or the second blown film (75) each define a layer of the laminate in their respective entirety.

4. Laminate according to any of the preceding claims, in particular according to claims 2 to 3, It is characterized by: The first blown film (70) and / or preferably the second blown film (75) comprises at least one barrier layer material.

5. The laminate according to claim 4, It is characterized by: The barrier layer material is selected from high-density polyethylene (HDPE), ethylene-vinyl alcohol copolymer (EVOH) and / or polyamide.

6. Laminate according to any one of the preceding claims, in particular according to claims 2 to 5, It is characterized by: The laminate (10) has at least one further barrier layer (80), which is in the form of a metallized layer, an aluminum oxide and / or silicon oxide layer, or a metal layer, in particular aluminum or an aluminum combination, and is arranged adjacent to the first blown film (70) and / or preferably adjacent to the second blown film (75), particularly preferably on the side of the second blown film (75) facing the outer layer (15).

7. Laminate according to any one of the preceding claims, in particular according to claims 2 to 6, It is characterized by: 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 acrylic esters.

8. Laminate according to any one of the preceding claims, in particular according to claims 2 to 7, It is characterized by: The first blown film (70) and / or the second blown film (75) contains titanium dioxide.

9. A laminate according to any one of the preceding claims, It is characterized by: The outer layer (15) is selected from a transparent film (20) or a non-transparent film and, if necessary, a printed part forming the design of the outer layer (15), wherein the printed part is designed as a reverse printed part (30) or a front printed part (35) in the case of a transparent film (20), and is designed as a front printed part (35) in the case of a non-transparent film (20).

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

11. Laminate according to any of the preceding claims, in particular according to claims 2 to 10, It is characterized by: The first blown film (70) and / or the second blown film (75) comprises low-density polyethylene, in particular LLDPE, as a material providing stability.

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

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

14. Laminate according to any of the preceding claims, in particular according to claims 2 to 13, It is characterized by: The laminate (10) has a polyolefin content greater than 90%, preferably greater than 95%, in particular a polyethylene content greater than 90%, preferably greater than 95%.

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

16. Use of a laminate (10) according to any one of the preceding claims for producing packages, in particular tubular bag packages, in particular erectable tubular bag packages.

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

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

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