Lid film for blister packaging material and blister packaging material

Abstract

To provide a blister package, a cover film, and a base film, which can eliminate the need for aluminum and can meet high-value drug requirements for high water and oxygen barrier properties cost-effectively.SOLUTION: The present invention provides a cover film (1) for sealing a base film (2) of a blister package for drugs, comprising two outer layers, namely, a cover layer (3) and a sealing layer (4), and one or more intermediate layers (5) situated between the cover layer (3) and the sealing layer (4). The cover layer (3) and the sealing layer (4) are polypropylene layers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lidding film and a blister pack comprising two outer layers, a cover layer and a seal layer, and one or more intermediate layers disposed between the cover layer and the seal layer. The present invention further relates to a blister packaging material.

[0002] Especially for high-value pharmaceuticals, packaging materials are used to ensure protection of the pharmaceutical from environmental influences, especially oxygen and moisture. This is the only way to maintain the efficacy of the pharmaceutical's active ingredients and contents when taken. Therefore, so-called blister packaging is often used for tablet-type pharmaceuticals. Blister packaging usually consists of a so-called push-through blister, also called a base member or bottom film, and a cover film, also called a blister film. The push-through blister is a molded product with a recess or cavity, usually made of plastic but sometimes aluminum. The cover film is usually tearable, also mainly made of aluminum, so that the pharmaceutical can be pushed out of the cavity in the base film and through the cover film by a person. Here, the basic advantages of blister packaging are its easy handling and compact packaging dimensions, which allow each pharmaceutical to be easily transported while being protected from possible environmental influences.

[0003] Here, aluminum has a high water vapor and oxygen barrier property, and at the same time, depending on the strength and thickness of the film, it can be relatively easy for the user to pierce the cover film and extrude each medicine in the cavity of the bottom film from the blister pack. However, aluminum as a material consumes a large amount of energy and resources, and even though aluminum is renewable, it still has a high energy demand.

[0004] Therefore, various approaches are known from the prior art to reduce or completely eliminate aluminium in blister packs while providing the same material properties as those provided by aluminium.

[0005] For example, from DE 10 2008 056 123 A1, blister packs are already known which comprise multilayer films consisting exclusively of various plastic or polymer layers, thereby making it possible to completely dispense with aluminum, in particular deep-drawable multilayer films with low water vapor and oxygen permeability, which are suitable for blister packs for pharmaceuticals and preferably have a layer composite of the PVC / PVDC / PCTFE / PVC type.

[0006] Furthermore, U.S. Patent Application Publication No. 2009 / 0208729 discloses a film structure characterized by including at least five layers, two of which are made of polyolefin, each of which has a gas barrier-forming layer on its opposing surface, and a foamed plastic layer between the two gas barrier layers. The two outer layers are made of a mixture of polyolefin and a binder, which allows the polyolefin layer to be bonded to the gas barrier-forming layer.

[0007] US Patent Application Publication No. 2019 / 0009963 discloses a plastic film molding for blisters, particularly tablet blisters, which includes a transparent support substrate and a translucent functional layer, wherein the translucent functional layer has properties such that the plastic film molding has a first color visible when viewed with incident light and a second color visible when viewed with transmitted light.

[0008] Furthermore, from German Utility Model No. 202021002835, a polyolefin blister pack is already known which consists of a lid film connected to a base film and which has one or more cavities produced by thermoforming for accommodating the products to be packaged, the blister pack being characterized in that the base film and the lid film essentially consist of polyolefins and that at least 50% by weight of the lid film consists of a cycloolefin polymer.

[0009] Furthermore, a method for producing a lid film for a push-through packaging material is already known from Swiss Patent Application No. 701216, in which the lid film is irradiated with electron beams to set the desired extrudability.

[0010] Based on this prior art, the object of the invention described herein is to provide a blister pack, a lid film and a bottom film, respectively, which can eliminate aluminum and which meet the high water and oxygen barrier requirements imposed on high-value pharmaceutical products at low cost.

[0011] This problem is solved by a lidding film according to the present claim 1. Furthermore, this problem is solved by a blister pack according to the parallel independent claim 18. Advantageous embodiments can be taken from the dependent claims.

[0012] In a first embodiment of the present invention, the lid film is for sealing a bottom film of a pharmaceutical blister pack, and the lid film comprises two outer layers, namely, a cover layer and a seal layer. Thus, the lid film itself is a multilayer film, in which the cover layer is the side of the lid film that faces the outside or environment, and the seal layer is the side of the lid film that faces the pharmaceutical product in the cavity normally present in the bottom film. Between these outer layers, namely, the cover layer and the seal layer, there are one or more intermediate layers.

[0013] The present invention is characterized in that the cover layer and the seal layer are made of polypropylene, i.e., polypropylene layers, which are as advantageous as polyvinyl chloride, which is often used for blister packs and the top and bottom members of blister packs, but which has fundamentally higher water vapor barrier properties.

[0014] In order to reduce the tendency to tear and the force required to push each drug from the base member through the lid film, the present invention provides in a further embodiment for the lid film that one or more intermediate layers between the two outer layers are copolymer layers, advantageously heterophasic copolymer layers. Particularly preferably, this is a heterophasic polypropylene copolymer layer. The heterophasic copolymer layer, also known as a block copolymer, comprises a polymer matrix with a dispersed rubbery copolymer phase. This matrix is a homopolymer or statistical copolymer matrix. The rubbery copolymer phase is a blend of an amorphous rubber, a rubbery polymer, and a semi-crystalline copolymer, where the rubbery polymer is typically an ethylene / propylene copolymer (rubber) in the case of a heterophasic polypropylene copolymer.

[0015] Preferably, at least one copolymer layer of one or more intermediate layers has a layer thickness of 20 to 260 μm, particularly preferably 100 to 180 μm, such a layer thickness improving the mechanical properties, i.e. the ability of the user to push out the pharmaceutical tablet, while the lid film remains compact.

[0016] Alternatively or additionally, in a further advantageous embodiment, the present invention further provides that the one or more intermediate layers of the lid film comprise at least one talc-reinforced polypropylene layer. Here, the talc-reinforced polypropylene is, for example, a composition of polypropylene and talc, the talc content typically varying between 20 and 35%. Compared to pure polypropylene, talc-reinforced polypropylene is characterized by higher heat and load resistance, as well as increased rigidity. However, this increased rigidity also means that the plastic is more susceptible to tearing. However, this very property is desirable in order to facilitate easier extrusion of the lid film, depending on the thickness of the talc-reinforced polypropylene layer.

[0017] Furthermore, in a further advantageous embodiment, the present invention provides that the one or more intermediate layers of the lid film comprise at least one cycloolefin layer, preferably a cycloolefin copolymer layer. The presence of the cycloolefin layer results in a significant improvement in the water vapor barrier, and the level of water vapor barrier can be varied solely by the layer thickness of the cycloolefin layer, which can be in the range of 20 to 260 μm, preferably in the range of 80 to 100 μm, and particularly preferably 80 μm. Here, this layer thickness of 80 μm represents an optimal compromise between the improvement in water vapor barrier and the further desired extrudability of the lid film.

[0018] However, in order to be able to meet the high oxygen barrier requirements imposed by some pharmaceutical products, the present invention provides in a further advantageous embodiment that the one or more intermediate layers of the lid film comprise at least one polyvinyl alcohol layer, preferably an ethylene-vinyl alcohol copolymer layer. Due to the combination of hydrogen bridges between the individual polymer chains present within polyvinyl alcohol and the crystalline structure, polyvinyl alcohol is one of the best available barriers to oxygen. Preferably, the polyvinyl alcohol layer has a thickness of 5 to 15 μm.

[0019] Depending on the desired properties of the lidding film, the invention in a further advantageous embodiment provides different materials for the outer layers, ie the cover layer and the sealing layer.

[0020] In a first alternative embodiment, the cover layer and / or seal layer is comprised of a polypropylene homopolymer layer. Polypropylene homopolymers are characterized by higher crystallinity, melting point, tensile strength, stiffness, and hardness compared to atactic polypropylene due to the isotactic orientation of groups, in this case methylene groups. High isotacticity ultimately leads to improved brittleness, which is advantageous for further improving the extrudability of the lid film. Preferably, the polypropylene homopolymer layer has a thickness of 10 to 140 μm, particularly preferably 60 to 110 μm.

[0021] In a further alternative embodiment, the cover layer and / or the seal layer consists of a polypropylene copolymer layer. Here, a distinction can be made between polypropylene block copolymers and polypropylene random copolymers. In the case of polypropylene block copolymers, the copolymer monomers are incorporated into the polymer chain in blocks, whereas in the case of polypropylene random copolymers, the copolymer monomers are randomly distributed in the molecular chain. In particular, the length and number of copolymer blocks or, respectively, the monomers of the block copolymer used can influence the properties of the resulting polypropylene copolymer, particularly its toughness behavior and rigidity. Finally, the use of a polypropylene copolymer layer can further influence the breaking strength and toughness of the lid film.

[0022] In a further alternative embodiment, the cover layer and / or seal layer comprises a nucleated polypropylene homopolymer layer. Nucleation or nucleation can be used to promote the formation of crystalline regions in atactic polypropylene, since the size and type of crystalline structures present can affect the mechanical properties of polypropylene. Not all regions of the polypropylene chain are isotactic or syndiotactic, and therefore not all regions of the polymer chain are incorporated into crystallites. Typically, the isotactic regions of polypropylene homopolymer crystallize in the form of α-spherulites. However, by adding an appropriate or specific nucleating agent, it is possible to achieve the formation of β-spherulites, which in turn improves the impact strength of the resulting polypropylene. Therefore, depending on the desired properties and application, it may be advantageous to use a nucleated polypropylene homopolymer with α-spherulites or β-spherulites in the cover layer and / or seal layer of the lid film. Here, the nucleated polypropylene homopolymer layer preferably has a thickness of 120 to 200 μm.

[0023] In order to further improve the water vapor and oxygen barrier properties, the invention provides in a further advantageous embodiment for the sealing layer that it is provided with a sealing lacquer which serves to further strengthen the water vapor or oxygen barrier properties without adversely affecting the desired properties of the lid film, in particular its tearability in order to allow any medicinal products present to be extruded through the lid film.

[0024] In order to make possible blister packs for pharmaceuticals child-resistant, it is common in the prior art to increase the thickness of the aluminum film layer or to design the blister pack so that the lid film cannot be pushed out and cannot be peeled off by small children without applying excessive force. Similarly, to be able to provide the child-resistant properties of the blister packs described herein, the present invention provides in a further advantageous embodiment that the blister pack comprises a barrier coating, preferably a peelable barrier coating, on the cover layer of the lid film. Particularly preferably, the coating is a biaxially oriented polypropylene layer. Biaxially oriented polypropylene acquires its particular properties through a specific stretching process, in which it is first stretched in the direction of the rollers, then stretched perpendicular to the direction of the rollers, and then fixed, and is characterized in particular by its high tensile strength, chemical, mechanical and thermal stability, and transparency. This is therefore ideal for protecting possible pharmaceutical blister packs from accidental opening by children, since when applied to the lid film, it becomes impossible to peel the lid film from the base of the blister pack without applying a corresponding amount of force.

[0025] In a second and final aspect, the present invention relates to a pharmaceutical blister pack comprising a lidding film according to the present invention.

[0026] The present invention will be described in more detail below using several exemplary embodiments. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic diagram of a multilayer film according to the present invention. [Figure 2] 1 shows a first example embodiment of a multi-layer lid film according to the present invention. [Figure 3] FIG. 2 shows a second example embodiment of a multi-layer lid film according to the present invention. [Figure 4] FIG. 10 shows a third example embodiment of a multi-layer lid film according to the present invention. [Figure 5] FIG. 10 shows a fourth embodiment of a multi-layer lid film according to the present invention.

[0028] Figure 1 shows a schematic diagram of a multilayer film according to the present invention. Lid film 1 and bottom film 2 each comprise two outer layers: cover layer 3 and seal layer 4. Cover layer 3 is the side of lid film 1 that faces the outside world or environment, while seal layer 4 is the side of lid film 1 that faces the pharmaceutical product within the cavity normally present in bottom film 2. Between these outer layers, cover layer 3 and seal layer 4, are one or more intermediate layers 5.

[0029] 2 shows a first embodiment of a lid film 1 according to the invention. In this case, the lid film 1 according to the invention comprises two outer layers and one intermediate layer 5, where the cover layer 3 and the seal layer 4 are polypropylene homopolymer layers 6, and the intermediate layer 5 is a copolymer layer 7, in particular a heterophasic random copolymer layer. This layer is suitable for pharmaceuticals that are not very sensitive to water or oxygen, and is also easier to extrude due to the significantly larger size of the intermediate layer 5 compared to the outer layers, since the intermediate layer 5 made of the heterophasic random copolymer 7 is more easily torn, stiffer and therefore less elastic than the polypropylene homopolymer layer 6.

[0030] 3 shows a lidding film 1 according to the invention, which is also suitable for water-sensitive pharmaceuticals. It has a cycloolefin layer 8 as an intermediate layer 5 between two polypropylene homopolymer layers 6 as cover layer 3 and seal layer 4.

[0031] Furthermore, to provide protection from both water and oxygen, a corresponding lidding film is shown in Figure 4. It similarly includes one polypropylene homopolymer layer 6 each as the cover layer 3 and the seal layer 4, as well as a total of three intermediate layers 5. The first two intermediate layers 5 are cycloolefin layers 8, which are directly adjacent to the outer layers, i.e., the cover layer 3 and the seal layer 4, respectively. Finally, a polyvinyl alcohol layer 9 is disposed between these two cycloolefin layers 8, which, due to its material properties, has a high affinity for oxygen. Thus, the lidding film 1 shown here in Figure 4 combines high water vapor barrier properties with high oxygen barrier properties.

[0032] Finally, Figure 5 shows a lidding film 1 according to the invention in which the two outer layers, the cover layer 3 and the seal layer 4, are nucleated polypropylene homopolymer layers 10, and the lidding film 1 has three intermediate layers 5. Again, each of the two outer layers is adjacent to a cycloolefin layer 8, which in turn surrounds a heterophasic random copolymer layer 7.

[0033] Thus, the above provides a blister packaging lidding film and a pharmaceutical blister packaging material that can eliminate aluminum in the film and meet the requirements for high water vapor and oxygen barrier properties at low cost. [Explanation of symbols]

[0034] 1 Lid film 2 Bottom Film 3 Cover Layer 4 Sealing Layer 5. Middle class 6 Polypropylene homopolymer layer 7 Copolymer Layer 8 Cycloolefin layer 9 Polyvinyl alcohol layer 10. Nucleated polypropylene homopolymer layer

Claims

1. 1. A lid film (1) for sealing a bottom film (2) of a pharmaceutical blister pack, comprising two outer layers, namely a cover layer (3) and a seal layer (4), and one or more intermediate layers (5) disposed between the cover layer (3) and the seal layer (4), characterized in that the cover layer (3) and the seal layer (4) are polypropylene layers (6, 7, 10), and the one or more intermediate layers (5) comprise a plurality of cycloolefin layers (8) between which polyvinyl alcohol layers (9) or copolymer layers (7) are disposed.

2. 2. Lidding film according to claim 1, wherein the one or more intermediate layers (5) comprise at least one copolymer layer (7), preferably a polypropylene copolymer layer.

3. Lidding film according to claim 2, wherein said at least one copolymer layer (7) has a layer thickness of 20 to 260 μm, preferably 100 to 180 μm.

4. 4. Lidding film according to any one of claims 1 to 3, wherein the one or more intermediate layers (5) comprise at least one talc reinforced polypropylene layer.

5. Lidding film according to any one of claims 1 to 3, wherein the cycloolefin layer (8) is a cycloolefin copolymer layer.

6. 6. Lidding film according to claim 5, wherein the cycloolefin layer (8) has a layer thickness of 20 to 260 μm, preferably 80 to 100 μm, particularly preferably 80 μm.

7. A lidding film according to any one of claims 1 to 3, wherein said one or more intermediate layers comprise at least one polyvinyl alcohol layer (9), preferably an ethylene-vinyl alcohol copolymer layer.

8. 8. Lidding film according to claim 7, wherein said at least one polyvinyl alcohol layer (9) has a layer thickness of 5 to 15 μm.

9. 4. Lid film according to any one of claims 1 to 3, wherein the cover layer (3) and / or the sealing layer (4) is a polypropylene homopolymer layer (6).

10. Lidding film according to claim 9, wherein the polypropylene homopolymer layer (6) has a layer thickness of 10 to 140 μm, preferably 60 to 110 μm.

11. Lid film according to any one of claims 1 to 3, wherein the cover layer (3) and / or the sealing layer (4) is a polypropylene copolymer layer.

12. Lidding film according to any one of claims 1 to 3, wherein the cover layer (3) and / or the sealing layer (4) is a nucleated polypropylene homopolymer layer (10).

13. The lidding film of claim 12, wherein the nucleated polypropylene homopolymer layer (10) has a layer thickness of 120 to 200 μm.

14. 4. The lid film according to claim 1, wherein the sealing layer (4) is provided with a sealing lacquer.

15. 4. The lid film according to claim 1, wherein the cover layer (3) has a barrier coating, preferably a peelable barrier coating.

16. 16. The lidding film of claim 15, wherein the barrier coating is a biaxially oriented polypropylene layer.

17. A blister pack for pharmaceuticals comprising a lidding film (1) according to any one of claims 1 to 3.

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