Barrier layer laminate and method of production thereof and use

Abstract

The invention relates to a barrier layer laminate (10) having a three-layer construction, wherein a barrier material layer (30) consisting of a mixture of ethylene-vinyl alcohol copolymer (EVOH) and butanediol-vinyl alcohol copolymer (BVOH) is embedded between two polyolefin layers (20), preferably of identical material, and also to a method of producing the barrier layer laminate (10) and to the use thereof for production of a packaging laminate having a barrier layer and / or for production of a package.

Description

[0001] Huhtamaki AG M / VRG-192-PC

[0002] PF / lz

[0003] Barrier layer laminate and methods for its manufacture and use

[0004] Description

[0005] The invention relates to a barrier layer laminate according to the preamble of claim 1, as well as a method for producing such a barrier layer laminate according to the preamble of claim 13, and furthermore its use according to the preamble of claim 15.

[0006] Barrier laminates have been known for some time and are used, among other things, to manufacture more or less flexible packaging that, due to a barrier layer embedded in the laminate, exhibits a certain degree of impermeability, particularly against oxygen but also against other gases. The so-called "Oxygen Transmission Rate" (OTR) is a particularly important measure of the degree of oxygen impermeability.

[0007] In the past, to produce barrier layer laminates with high oxygen impermeability or low OTR values, one or more layers of a barrier layer material, such as ethylene vinyl alcohol copolymer (EVOH) or polyvinyl alcohol (PVOH) or another material, such as aluminum, were embedded in the barrier layer laminate or between its structural layers.

[0008] However, a significant disadvantage of these previously known barrier layer laminates is that achieving good, i.e., low OTR values, such as less than 0.1 cm, requires... 3At a temperature of 23°C and 50% relative humidity, per square meter per 24 hours, very high barrier layer thicknesses of EVOH and / or PVOH, namely in the range of 10 pm to 30 pm, are necessary. This, in turn, leads to a total thickness of such previously known barrier layer laminates that is also very thick, i.e., in the range of approximately 100 pm and greater. These large layer thicknesses, in turn, bring with them numerous disadvantages, namely high costs due to the high material requirements, as well as high stiffness and the associated low flexibility of such barrier layer laminates. A further disadvantage is that MEISSNER BOLTE M / VRG-192-PC

[0009] 2 such known barrier layer laminates due to their very high

[0010] Barrier layer material components are practically impossible or very difficult to recycle.

[0011] The invention is therefore based on the objective of providing and specifying a cost-effectively manufactured barrier layer laminate with very low OTR values, as well as a method for its production and use, while avoiding the aforementioned disadvantages.

[0012] This problem is solved by a barrier layer laminate according to claim 1 and by a method for producing such a barrier layer laminate according to claim 13 and its use according to claim 15.

[0013] In particular, the problem is solved by a barrier layer laminate having a three-layer structure, wherein a barrier material layer consisting of a mixture of ethylene vinyl alcohol copolymer (EVOH) and butanediol vinyl alcohol copolymer (BVOH) is embedded between two, preferably material-identical, polyolefin layers.

[0014] As has been shown in the course of developing the present invention, a mixture of EVOH and BVOH is optimally suited for generating a barrier layer with extremely low oxygen permeability properties, wherein both the barrier and structural material properties of the two materials EVOH and BVOH complement each other in a surprisingly advantageous synergistic manner, and the barrier effect of the mixture of these two barrier layer materials used according to the invention goes significantly beyond a purely additive barrier effect of EVOH and BVOH.Furthermore, it was found according to the invention that the fundamental moisture sensitivity of BVOH can be significantly reduced by the simultaneous use of EVOH in the same mixture, and the mechanical properties of BVOH can also be significantly improved, making such a barrier material layer ideally suited to be embedded between two, preferably material-identical, polyolefin layers and to act as an excellent, virtually gas- and especially oxygen-impermeable barrier layer for the resulting laminate.

[0015] According to a particularly preferred embodiment of the invention, a mixing ratio of EVOH : BVOH in weight percent in the range of 60 : 40 to 95 : 5, preferably in the range of 70 : 30 to 90 : 10, and particularly preferably in the range of 75 : 25 to 85 : 15, especially of about 80 : 20, has proven particularly effective. MEISSNER BOLTE M / VRG-192-PC

[0016] 3

[0017] Furthermore, it has proven particularly advantageous according to the invention if the mixture of ethylene vinyl alcohol copolymer (EVOH) and butanediol vinyl alcohol copolymer (BVOH) is produced in the molten state of the components and / or introduced between the polyolefin layers.

[0018] According to this embodiment of the invention, it is possible either to intimately compound the materials EVOH and BVOH before their use, i.e. to intimately mix them from or in their respective molten state, or to subject them to a common extrusion, for example through a slot die, in which the barrier material layer is introduced as a barrier layer between the two polyolefin layers.

[0019] Advantageously, it is therefore possible to form the barrier layer laminate by extruding the barrier material layer onto two existing polyolefin films and joining them together to form the barrier layer laminate.

[0020] According to the invention, the barrier material layer has a very thin layer thickness, namely in the range of 0.5 pm to 4 pm, preferably in the range of 0.8 pm to 3.5 pm and particularly preferably in the range of 1 pm to 2 pm, especially in the range of 1.2 pm to 1.8 pm, so that the barrier layer laminate according to the invention can advantageously have a total layer thickness of significantly less than 80 pm to 100 pm, as previously necessary according to the prior art.

[0021] Within the scope of the invention, it has been shown that when using the barrier layer material according to the invention as a barrier between two polyolefin layers, total layer thicknesses of the barrier layer laminate according to the invention in the range of less than 50 pm, in particular less than 40 pm up to 18 pm to 22 pm, particularly preferably 20 pm, are possible, whereby OTR values ​​of less than 50 pm are extremely advantageous according to the invention.

[0022] 0.1 cm 3 / square meters per 24 hours at a temperature of 23°C and a relative humidity of 50%.

[0023] According to the invention, the polyolefin layers of the barrier layer laminate, according to one embodiment of the invention, have a layer thickness, in particular an identical thickness, which is in the range of 5 pm to 40 pm, preferably in the range of 7 pm to 30 pm, and particularly preferably in the range of 9 pm to 25 pm, especially in the range of 9.5 pm to 19 pm. MEISSNER BOLTE M / VRG-192-PC

[0024] 4

[0025] Using such thin polyolefin layers in combination with a very thin barrier layer, an overall very thin and therefore also flexible barrier layer laminate with excellent barrier properties can be produced, which, among other things, is both cost-effective to manufacture due to the low material requirement resulting from the small thickness, as well as flexible and versatile in its application and can be used, for example, to improve the barrier properties of conventional films.

[0026] According to a further preferred embodiment of the invention, an adhesion promoter layer, for example in the form of a primer layer, with a thickness in the range of 0.1 pm to 3 pm, preferably in the range of 0.5 pm to 2 pm, and particularly preferably in the range of 1 pm to 1.5 pm, is arranged between the polyolefin layers and the barrier material layer, in particular between each of them. This primer layer improves the adhesion of the barrier material layer to the respective polyolefin layers. According to the invention, the primer layer is kept extremely thin, since it serves only to condition the surface of the polyolefin layers and itself has no adhesive properties whatsoever, particularly not in the sense of a conventional adhesive, for example, one based on polyurethane.In a highly advantageous manner, such an extremely thin primer layer in the barrier layer laminate according to the invention thus contributes practically nothing to the overall thickness of the barrier layer laminate according to the invention; the primer layer therefore has no effect on the flexibility. The same applies to the introduction of foreign material, which, according to the invention, has a highly advantageous effect on the recyclability of the barrier layer laminate according to the invention.

[0027] As an alternative to a primer layer, an adhesion promoter layer can also be used according to the invention to optimize adhesion between the barrier material layer and the polyolefin layers adjacent on both sides. In this case, an adhesion promoter layer is located on both sides of the barrier material layer. Depending on the laminate or as desired, it is also possible for the primer layer to be arranged alternately on one side of the barrier material layer and an adhesion promoter layer to be arranged alternately on the other side of the barrier material layer, wherein the thickness of the adhesion promoter layer essentially corresponds to the thickness of the primer layer.

[0028] According to the invention, the adhesion promoter layer has a polyolefin base with a polyolefin content in the range of 95 wt.% to 99.5 wt.%, preferably in the range of 97 wt.% to 99 wt.%, and particularly preferably in the range of 97.5 wt.% MEISSNER BOLTE M / VRG-192-PC

[0029] 5 to 98.5 wt.%, and furthermore, to complete to 100 wt.%, a non-pH-neutral, preferably acidic component, in particular maleic anhydride. According to a preferred embodiment of the invention, as explained below, a polyethylene, for example HDPE, is preferred as the polyolefin, since in this way the greatest possible material uniformity can be achieved for the barrier layer laminate according to the invention, which in turn advantageously contributes significantly to the recyclability of the barrier layer laminate according to the invention.

[0030] According to a further preferred embodiment of the invention, the two polyolefin layers are preferably polyethylene layers, namely in particular preferably made of a high-density polyethylene, such as HDPE.

[0031] As mentioned above, the barrier layer laminate according to the invention can be produced by extrusion lamination. In this process, two polyolefin films are coated with a barrier layer material consisting of a mixture of EVOH and BVOH. The barrier layer material produced in this way can then be unstretched and used.

[0032] According to an alternative embodiment of the invention, the barrier layer laminate according to the invention, particularly in its entirety, is stretched in the machine direction with a stretch ratio in the range of 1 : 4 to 1 : 12, preferably in the range of 1 : 5 to 1 : 10, and particularly preferably in the range of 1 : 5 to 1 : 8.

[0033] In this way, the barrier layer laminate according to the invention can be stretched and the molecular chains present in the individual layers of the barrier layer laminate can be oriented, so that at least partially crystalline regions are formed within the individual layers of the barrier layer laminate, which further improves the barrier effect of the barrier layer laminate according to the invention. Stretch ratios in the range of 1:5 to 1:8 have proven to be particularly advantageous in this regard.

[0034] According to a further particularly advantageous embodiment of the invention, the barrier layer laminate is free of adhesive, in particular free of polyurethane-based adhesive.

[0035] In this way, the barrier layer laminate according to the invention can also be used in areas where special hygiene is important, since the adhesive-free nature of the barrier layer laminate according to the invention ensures that there is no migration of adhesive into any filling material in a MEISSNER BOLTE M / VRG-192-PC

[0036] 6

[0037] The barrier layer laminate can be used in packaging manufactured using this method. Therefore, the barrier layer laminate according to the invention is also suitable for the production of packaging for food, pharmaceuticals, and, for example, animal feed.

[0038] According to the invention, the barrier layer laminate has a polyolefin content, in particular an HDPE content, of greater than 91 wt.%, preferably greater than 95 wt.% and particularly preferably greater than 98 wt.%, in particular greater than 99 wt.%.

[0039] Thus, the barrier layer laminate according to the invention is almost materially homogeneous, which significantly improves the recyclability of the barrier layer laminate according to the invention compared to barrier layer laminates known to date, which in turn contributes to the fact that the material of the barrier layer laminate according to the invention can be used for the production of future packaging.

[0040] Furthermore, the object of the invention, as mentioned above, is also achieved by a method for producing a barrier layer laminate according to the above descriptions and specifications, wherein in this method a barrier material layer consisting of a mixture of ethylene vinyl alcohol copolymer (EVOH) and butanediol vinyl alcohol copolymer (BVOH) is extruded between two, preferably material-identical, polyolefin layers, preferably HDPE layers or HDPE films.

[0041] According to the procedure, the HDPE films can be coated with a primer layer on their respective side associated with the barrier material layer prior to extrusion coating with the barrier material layer, thereby improving the adhesion of the barrier layer material to the surrounding polyolefin layers.

[0042] Furthermore, the object of the invention is also achieved by using the barrier layer material described above to produce a laminate, in particular a packaging laminate with a barrier layer and / or to produce packaging with a barrier layer.

[0043] In summary, the features and advantages of the invention can be briefly summarized as follows.

[0044] A particularly advantageous barrier effect of the new invention

[0045] Barrier layer laminate can be improved by adding an additional granulate, MEISSNER BOLTE M / VRG-192-PC

[0046] 7. BVOH, which is currently the standard material for generating an OTR barrier according to the prior art, namely EVOH. According to the invention, it has been shown that while BVOH possesses properties for an exceptionally high OTR barrier, its use has been very limited according to the prior art due to its high water sensitivity. The barrier material mixture used according to the invention has solved the problem of BVOH's high water and moisture sensitivity in a surprisingly simple way by mixing, or in particular compounding, a high proportion of EVOH with a lower proportion of BVOH. This provides the overall barrier material used according to the invention with the necessary protection, especially in high humidity, such as in the tropics, and ensures a reliable barrier effect.

[0047] It has been found according to the invention that a combination of these two materials, which are known per se, improves the respective weaknesses of each other material not only additively, but synergistically by a factor of many through a special mixing ratio according to the invention.

[0048] Furthermore, the combination of these two materials EVOH and BVOH also contributes to a significantly better separability of the layers of the barrier layer laminate according to the invention compared to the previous state of the art with regard to recyclability, should this be desired.

[0049] Further embodiments of the invention are set out in the dependent claims.

[0050] The invention is described below with reference to exemplary embodiments, which are explained in more detail with reference to the schematic diagram. This diagram shows:

[0051] Fig. 1 shows a schematic basic structure of the barrier layer laminate according to the invention.

[0052] As can be seen in Fig. 1, the barrier layer laminate 10 according to the invention has a basic three-layer structure consisting of two polyolefin layers 20, between which a barrier material layer 30 is embedded using an adhesion promoter layer 40 in each case.

[0053] According to a first embodiment, the barrier layer laminate 10 according to the invention is produced by an extrusion coating, wherein the two polyolefin layers 20, which preferably consist of HDPE and have a layer thickness of approximately 18 pm to 20 pm, are applied to both sides of the barrier material layer MEISSNER BOLTE M / VRG-192-PC

[0054] 8

[0055] The barrier material layer 30 is arranged between the two polyolefin layers 20 according to the invention. Between the barrier material layer 30 and each adjacent polyolefin layer 20, in particular an HDPE layer, an adhesion promoter layer 40 based on polyolefin, in particular polyethylene, with a maleic anhydride content of essentially 2 wt.%, is arranged. The thickness of the adhesion promoter layer 40 is essentially in the range of 1 pm to 1.5 pm. The barrier material layer 30 consists of a mixture of EVOH and BVOH with a BVOH to EVOH ratio of 1:5. The thickness of the barrier material layer 30 is 2 pm. The total thickness of the barrier layer laminate 10 according to the invention is 40 pm, with the two HDPE layers each having essentially identical thicknesses.

[0056] According to a second embodiment, the barrier layer laminate 10 according to the invention, which has the same layer sequence polyolefin layer, preferably HDPE layer, 20 / adhesion promoter layer 40 / barrier material layer 30 / adhesion promoter layer 40 / polyolefin layer, preferably HDPE layer, 20, as in the previous embodiment, is stretched in the machine direction with a stretch ratio of 1:5 after the extrusion coating of the two polyolefin layers 20 and adhesion promoter layers 40 with the barrier material layer 30 arranged between them. According to this second embodiment as well, the barrier material layer 30 consists of a mixture of EVOH and BVOH with a BVOH to EVOH mixing ratio of 1:5.The initial thickness of the "raw" barrier layer laminate 10, which results from the extrusion coating of the two polyolefin layers 20 including the barrier material layer 30 arranged between them, is 100 pm before stretching, i.e., in its "raw" state. The thickness of the barrier material layer 30 is approximately 5 pm before stretching and approximately 1 pm after stretching. After stretching, the two polyolefin layers have a thickness in the range of 9 pm to 9.5 pm, resulting in a total thickness of the stretched barrier layer laminate of essentially 20 pm.

[0057] Both the barrier layer laminate 10 according to the first embodiment and the barrier layer laminate 10 according to the second embodiment exhibit OTR values ​​of less than 0.1 cm. 3 / square meter per 24 hours at a temperature of 23°C and a relative humidity of 50%.

[0058] It should be noted at this point that all parts described above, considered individually and in any combination, especially those shown in the drawings MEISSNER BOLTE M / VRG-192-PC

[0059] The details shown in section 9 are claimed to be essential to the invention. Modifications thereof are familiar to those skilled in the art.

[0060] Reference symbol list

[0061] 10 barrier layer laminate

[0062] 20 Polyolefin layer

[0063] 30 Barrier material layer

[0064] 40 bond mediator layer

Claims

Huhtamaki AG M / VRG-192-PC PF / lz Barrier layer laminate and methods for its manufacture and use Claims 1. Barrier layer laminate (10), which is characterized by the fact that the barrier layer laminate (10) has a three-layer structure, wherein a barrier material layer (30) consisting of a mixture of ethylene vinyl alcohol copolymer (EVOH) and butanediol vinyl alcohol copolymer (BVOH) is embedded between two, preferably material-identical, polyolefin layers (20).

2. Barrier layer laminate according to claim 1, characterized by the fact that the mixing ratio of EVOH : BVOH in weight percent is in the range of 60 : 40 to 95 : 5, preferably in the range of 70 : 30 to 90 : 10 and particularly preferably in the range of 75 : 25 to 85 : 15, especially at 80 :

20.

3. Barrier layer laminate according to one of the preceding claims, characterized by the fact that the mixture of ethylene vinyl alcohol copolymer (EVOH) and butanediol vinyl alcohol copolymer (BVOH) is produced in the molten state of the components and / or is introduced between the polyolefin layers (20).

4. Barrier layer laminate according to one of the preceding claims, characterized by the fact that the barrier material layer (30) has a layer thickness in the range of 0.5 pm to 4 pm, preferably in the range of 0.8 pm to 3.5 pm and particularly preferably in the range of 1 pm to 2 pm, especially in the range of 1.2 pm to 1.8 pm.

5. Barrier layer laminate according to one of the preceding claims, characterized by the fact that the polyolefin layers (20) have a layer thickness, in particular of identical thickness. MEISSNER BOLTE M / VRG-192-PC 2 exhibiting values ​​in the range of 5 |jm to 40 |jm, preferably in the range of 7 pm to 30 pm and particularly preferably in the range of 9 pm to 25 |jm, especially in the range of 9.5 pm to 19 pm.

6. Barrier layer laminate according to one of the preceding claims, characterized by the fact that an adhesion promoter layer (40), for example in the form of a primer layer, is arranged between the polyolefin layers (20) and the barrier material layer (30), in particular in each case.

7. Barrier layer laminate according to one of the preceding claims, characterized by the fact that the polyolefin layers (20), preferably both, are polyethylene layers, in particular high-density polyethylene (HDPE).

8. Barrier layer laminate according to claim 7, characterized by the fact that the adhesion promoter layer (40) and / or primer layer has a layer thickness in the range of 0.1 pm to 3 pm, preferably in the range of 0.5 pm to 2 pm and particularly preferably in the range of 1 pm to 1.5 pm, wherein the adhesion promoter layer (40) has a polyolefin content in the range of 95 wt.% to 99.5 wt.%, preferably in the range of 97 wt.% to 99 wt.%, and particularly preferably in the range of 97.5 wt.% to 98.5 wt.%, and furthermore comprising, to complete to 100 wt.%, a non-pH-neutral, preferably pH-acidic component, in particular maleic anhydride.

9. Barrier layer laminate according to one of the preceding claims, characterized by the fact that the barrier layer laminate (10) is produced by extrusion lamination and is unstretched.

10. Barrier layer laminate according to any one of the preceding claims 1 to 8, characterized by the fact that the barrier layer laminate (10), in particular in its entirety, is stretched in the machine direction with a stretch ratio in the range of 1 : 4 to 1 : 12, preferably in the range of 1 : 5 to 1 : 10, and particularly preferably in the range of 1 : 5 to 1 :

8. MEISSNER BOLTE M / VRG-192-PC 3 11. Barrier layer laminate according to one of the preceding claims, characterized by the fact that the barrier layer laminate (10) is free of adhesive, in particular free of polyurethane-based adhesive.

12. Barrier layer laminate according to one of the preceding claims, characterized by the fact that the barrier layer laminate (10) has a polyolefin content, in particular HDPE content, of greater than 91 wt.%, preferably greater than 95 wt.% and particularly preferably greater than 98 wt.%, in particular greater than 99 wt.%.

13. A method for producing a barrier layer laminate (10) according to one of the preceding claims, characterized by the fact that a barrier material layer (30) consisting of a mixture of ethylene vinyl alcohol copolymer (EVOH) and butanediol vinyl alcohol copolymer (BVOH), optionally in the presence of a respective adhesion promoter layer (40) on both sides of the barrier material layer (30), is extruded between two, preferably material-identical, polyolefin layers (20), preferably HDPE layers or HDPE films.

14. Method according to claim 13, characterized by the fact that the HDPE films (20) are coated with a primer layer on their respective side associated with the barrier material layer (30) prior to extrusion coating with the barrier material layer (30).

15. Use of the barrier layer laminate (10) according to any one of the preceding claims 1 to 12 and / or manufactured according to any one of the preceding claims 13 to 14 for the manufacture of a packaging laminate with a barrier layer and / or for the manufacture of packaging.

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