Packaging film, in particular cover film for a blister pack, and blister pack

Abstract

A packaging film (10), in particular for a blister pack (32), comprises: - a polymer film (22) as a top layer (24) having a first layer thickness (d), and - a sealable polyester film (12) as a base layer (14) having a second layer thickness (D), wherein the base layer (14) is designed for heat-sealing connection to a compatible plastics surface, wherein the base layer (14) has an exposed sealable sealing side (14a) and a connection side (14b) facing the top layer (24), wherein the second layer thickness (D) is greater than the first layer thickness (d), wherein the base layer (14) has local weakened material portions (26), which do not completely penetrate the base layer (14) in the thickness direction, wherein the base layer (14) has a smaller second layer thickness (D-T) in the region of extent of the weakened material portions (26) compared to an unweakened base layer region without weakened material portions (26).

Description

[0001] Packaging film, in particular lidding film for blister packaging, and blister packaging

[0002] Description

[0003] The present invention relates to a multilayer packaging film, in particular for blister packaging, with a polyester layer as the thickest layer of the packaging film. The polyester layer is thus the base layer of the packaging film.

[0004] The base layer exhibits local material weaknesses that do not fully penetrate the base layer in the thickness direction. In the area where the local material weaknesses extend, the thickness of the base layer is thinner than in the remaining unweakened areas of the base layer.

[0005] WO 2016 / 140758 A1 discloses a packaging film with a total thickness of 15 μm to 90 μm as a lidding film for a blister pack. The film has an outer structure-forming layer, thus forming a base layer, and on its side facing a blister carrier, a sealing layer made of a thermoplastic polymer that melts at lower temperatures than the base layer. The base layer can be formed, among other materials, from polyethylene terephthalate. On the side opposite the sealing layer, the packaging film known from WO 2016 / 140758 A1 has cuts that do not completely penetrate the base layer in the thickness direction.

[0006] WO 2016 / 140758 A1 discloses various material combinations for the packaging film, including an embodiment in which the base layer comprises polypropylene homopolymer and the sealing layer comprises polypropylene copolymer. In another embodiment of WO 2016 / 140758 A1, the base layer comprises semicrystalline polyethylene terephthalate and the sealing layer comprises an amorphous polyethylene terephthalate copolymer.

[0007] The material weakenings, which are introduced exclusively into the base layer and not into its sealing layer, are mechanically cut into the base layer by blades using a knife roller. In the case of WO 2016 / 140758 A1, the material weakenings are angled or V-shaped incisions in the extension area of ​​the base layer. The incisions are distributed as widely as possible across the base layer to avoid having to align the base layer relative to the product receiving cavities of a blister carrier to be connected to it.

[0008] WO 2016 / 140758 A1 also discloses a blister pack with the aforementioned packaging film as the lidding film. A blister carrier has a removal side and a support side. The blister carrier has product receiving recesses formed integrally with the blister carrier. These recesses are concavely curved on the removal side and into which products such as tablets, capsules, chewing gum, small parts, and the like can be inserted. On the support side, the product receiving recesses are convexly curved. On the removal side, the packaged products are removed from the blister pack. The support side allows the blister pack to rest on a surface while remaining accessible.

[0009] The blister carrier is formed from a flat polymer material by deep drawing or similar. The lidding film with its sealing layer is thermally bonded to the removal side of the blister carrier by heat sealing. This closes the product receiving recesses with the lidding film. The lidding film, with its material weakenings, is designed as a push-through film and is designed to burst under pressure. The pressure is usually exerted by the consumer by exerting force on the contact side. The contents of a product receiving recess are pressed against the lidding film, whereby in the area of ​​a material weakening, the tension acting on the lidding film or in the lidding film locally exceeds the tear strength of the lidding film. This causes the lidding film to tear locally and release the contents of the underlying product receiving recess for removal.

[0010] The material of the blister carrier of the blister pack known from WO 2016 / 140758 A1 is selected with regard to the recycling of the used blister pack so that the lidding film and the blister carrier can be recycled in a common recycling stream.

[0011] One disadvantage of the known packaging film results from its advantage: due to the material weaknesses, it can happen that during the production of the packaging film or a blister pack with the packaging film, cracks are introduced into the packaging film due to mechanical stresses in the area of ​​the material weaknesses that occur during the process, and the packaging film thus becomes unusable waste in sections.

[0012] It is therefore an object of the present invention to provide a packaging film as a possible lidding film and push-through film of a blister pack, which can be produced as safely as possible with as little waste as possible while at the same time ensuring high removal and opening security of a blister pack formed therewith.

[0013] The present invention achieves this object by a packaging film, in particular as a push-through lidding film for a blister pack, comprising: a polymer film as a cover layer with a first layer thickness, and a sealable polyester film as a base layer with a second layer thickness, which is designed for heat-sealing connection to a compatible plastic surface, wherein the base layer has an exposed sealable sealing side and a connection side facing the cover layer, wherein the second layer thickness is greater than the first layer thickness, wherein the base layer has local material weakenings which do not completely penetrate the base layer in the thickness direction, wherein the base layer has a smaller second layer thickness in the area of ​​extension of the material weakenings compared to an unweakened base layer area without material weakenings.

[0014] By using the top layer in addition to the base layer, the tear strength of the packaging film can be increased to such an extent that mechanical stresses occurring during the manufacturing process, such as when the packaging film is deflected around pulleys and when it is combined with a blister carrier and sealed onto the blister carrier, no longer exceed the tear strength of the packaging film. The packaging film and the blister pack formed with its participation can thus be produced without failure of the packaging film.

[0015] Furthermore, the fact that the first layer thickness assigned to the cover layer is smaller than the second layer thickness of the base layer prevents the cover layer from influencing the puncture properties of the packaging film to the detriment of consumers.

[0016] This increases manufacturing reliability without reducing the usability of the film.

[0017] Preferably, the second layer thickness is approximately four to eight times the thickness of the first layer. Particularly preferably, the second layer thickness is five to six and a half times the thickness of the first layer. This ensures that the packaging film has greater tear resistance than the base layer without the force required to push through the packaging film as the lidding film of a blister pack becoming excessively large. Ultimately, a blister pack for medications should be particularly easy to open, especially by sick and weakened individuals.

[0018] The base layer and the cover layer preferably each have a substantially uniform thickness along their surface extent, with the exception of the material weaknesses in the base layer. The material weaknesses in the base layer are preferably linear material weaknesses, such as can be created by blades or lasers. Preferably, the material weaknesses are mechanical incisions in the base layer created by blades. Further preferably, the material weaknesses extend across the entire width of a packaging film blank, as intended and cut to form a specific package, in particular a blister pack.According to a preferred embodiment, the material weakenings extend continuously and uninterruptedly from a first edge of a packaging film blank to another second edge of the packaging film blank, for example to a second edge opposite the first edge in the width direction, preferably parallel, or to a second edge extending transversely, preferably orthogonally, to the first edge. Preferably, the linear material weakenings do not intersect to provide a penetration force necessary to push through the packaging film that is as uniform as possible across the surface area of ​​the packaging film.

[0019] To facilitate their outer packaging in a cuboid carton or box, packaging film blanks and blister packs formed therewith often have a fundamentally rectangular shape such that they each have two parallel edges, wherein the two parallel pairs of edges run at right angles to each other. The corners of the packaging film blank and of a blister pack formed therewith can be rounded to prevent injury to the consumer. In such a case, the material weakenings can preferably run at an angle to the side edges in order to provide the most uniform puncture force possible, which is necessary to push objects packaged in a blister pack through the packaging film regardless of their shape and their orientation relative to the material weakenings.The angle of incidence of the preferably linear material weakenings to an edge of the packaging film is preferably between 30° and 60°, more preferably between 40° and 50°, most preferably about 45°.

[0020] Preferably, the base layer has only one type of material weakening, which is particularly preferably the linear incisions mentioned above.

[0021] Preferably, the material weakenings extend, when considering their mean values ​​of their depth dimension to be determined over their respective courses, in the thickness direction of the base layer over at least 40% of the second layer thickness, i.e. the thickness of the sealable polyester film, in order to sufficiently reduce the strength of the base layer so that the material coherence of the base layer can be locally destroyed by pressure of a packaged article against the sealing side of the base layer and thereby an opening of a product receiving recess covered by the packaging film can be brought about.Likewise, the material weakenings, again considering the stated mean values, preferably extend in the thickness direction of the base layer over no more than 70%, preferably no more than 60%, of the second layer thickness, in order not to weaken the base layer and thus the packaging film to such an extent that it can no longer withstand its own manufacturing process due to the mechanical stresses occurring during it.

[0022] Due to the inherent elasticity of the base layer, the depth dimensions, along which the material weakenings extend into the base layer along the thickness direction, are subject to relatively large fluctuations in magnitude along their, preferably linear, course. The specification of a depth dimension along which a material weakening extends into the base layer in the thickness direction is therefore the specification of an averaged mean depth dimension along its course, from which a material weakening along its extension can deviate locally by up to 30% in both directions relative to this mean value.

[0023] For example, for a packaging film with a base layer and a cover layer, a minimum residual thickness of approximately 13 μm after introducing the material weakenings has proven advantageous. For the desired tearability of the packaging film or for the desired strength in the area of ​​the material weakenings, a minimum residual thickness of the packaging film with a base layer and cover layer in the range of 13 μm to 17 μm is advantageous.

[0024] Depending on the thickness of the cover layer and an adhesive layer preferably arranged between the cover layer and the base layer, the advantageous minimum residual thickness of the packaging film for a preferred base layer with a total thickness of 30 μm results in a minimum penetration depth of the material weaknesses in the range of between 19 μm and 25 μm. With a total thickness of 30 μm, the depth dimension of mechanically incised material weaknesses in the base layer can vary between 4 μm and 5 μm.

[0025] To mechanically cut into material weaknesses in the base layer, the base layer is passed through a nip between a knife roller and a counter roller that presses the base layer against the knife roller's blades. The blades project radially from a base surface of the knife roller. The nip width is adjusted to the remaining minimum thickness, taking into account the material elasticity of the packaging film or the base layer, or corresponds to it.

[0026] According to one embodiment of the present invention, the local material weaknesses can be formed on the sealing side. This provides an advantageously smooth surface on the bonding side for bonding to the cover layer. This prevents the accumulation of dirt in the material weaknesses, for example, caused by touching the packaging film, since the blister carrier of a blister pack formed with the packaging film generally completely covers the material weaknesses on the sealing side.

[0027] When the material weakenings are formed on the sealing side, the absolute value of the depth dimension of the material weakenings is greater than when the material weakenings are formed on the bonding side. The depth dimension fluctuation range can then be, for example, the above-mentioned ± 5 μm. When the material weakenings are formed on the sealing side, either the entire packaging film or just the base layer to be weakened can be passed through the aforementioned roller gap, since the sealing side is accessible in both cases.

[0028] According to another embodiment of the present invention, the local material weaknesses can be formed on the connection side. This advantageously provides a smooth sealing side for connection to the blister carrier. Furthermore, the cover layer then spans the material weaknesses, which in turn prevents an undesirable accumulation of dirt in the material weaknesses. If the material weaknesses are formed as mechanical linear incisions as described above, the material weaknesses have a groove-like shape into which liquid and pasty dirt can penetrate and remain. If the material weaknesses are formed on the connection side, the fluctuation in the depth dimension of the material weaknesses is smaller around their mean value. For example, it can be the above-mentioned ± 4 pm.When forming material weakenings on the joining side, the base layer must be guided through the roll gap without the cover layer. Due to the local fluctuation in the depth of weakness of up to ± 4 μm, undesirable complete penetration of the base layer across its entire thickness can occur in very isolated and only localized cases. However, this can be tolerated due to the unweakened cover layer applied to the joining side after the material weakenings have been introduced into the base layer. Preferably, however, the base layer only has material weakenings that do not completely penetrate the base layer in the thickness direction.

[0029] To ensure that the top layer only slightly increases the overall strength of the packaging film compared to the base layer alone, thus ensuring its processability during production, the top layer preferably has a thickness in the range of 3.5 μm to 6 μm. More preferably, the top layer has a thickness in the range of 4 μm to 5 μm, particularly preferably 4.5 μm.

[0030] Under the above-mentioned thickness ratios, the base layer preferably has a thickness in the range of 23 μm to 40 μm. More preferably, the base layer has a thickness in the range of 26 μm to 33 μm, particularly preferably 30 μm, in order to provide the packaging film with sufficient basic structure while still allowing sufficient penetration.

[0031] According to a preferred embodiment, the packaging film comprises an adhesive layer arranged between the cover layer and the base layer, which adhesive layer connects the base layer and the cover layer to one another. The adhesive layer preferably wets both the cover layer and the base layer. Such an adhesive layer can act as an advantageous elastic mechanical buffer between the cover layer and the base layer, which distributes mechanical loads acting on the cover layer during the production of the packaging film or a blister pack formed with its participation towards the base layer over a larger effective area and spreads load peaks over a longer effective period. Thus, for example, a temporally and spatially punctual peak load acting on the cover layer from the outside can act on the base layer over a larger effective area and over a longer period of time than on the cover layer.This also helps to increase the processability of the packaging film.

[0032] The adhesive layer preferably has a surface-related application weight in the range of 1.5 to 5.0 g / m 2The application weight per unit area applies to the dry state of the adhesive layer, which is usually applied wet, for example as a dispersion, preferably as an aqueous dispersion. The adhesive layer can be a polyurethane-based polymer or can be a polymer applied using a binder. One possible adhesive is, for example, a two-component, solvent-free, polyurethane-based laminating adhesive, such as is commercially available under the trade name Loctite Liofol LA 7782 / LA 6083. Another possible adhesive is, for example, a two-component, solvent-based, polyurethane-based laminating adhesive, such as is commercially available under the trade name Loctite Liofol LA 3644-21 MHS / LA 6255.

[0033] According to an alternative embodiment, the sealable polyester film of the base layer can be a double-sided sealable polyester film that is also sealable on the bonding side. While this does not fundamentally preclude the use of an adhesive layer between the cover layer and the base layer, the cover layer can then preferably be bonded to the base layer by thermal lamination using the sealable bonding side of the sealable polyester film. This could eliminate the need for an adhesive during production of the packaging film, facilitating the production of the packaging film and its recyclability.

[0034] The top layer and / or the base layer can each be formed from an oriented polymer. In principle, the top layer and / or the base layer can be formed from a monoaxially oriented polymer. However, the top layer and / or the base layer are preferably formed from a biaxially oriented polymer, which increases the child resistance of a blister pack formed with the packaging film.

[0035] The sealable polyester film of the base layer preferably has a core layer made of polyester and, on its sealing side, a sealing layer made of copolyester. The core layer is preferably formed of polyethylene terephthalate. The core layer is particularly preferably made of polyethylene terephthalate. The sealing layer on the sealing side is then preferably formed of a polyethylene terephthalate copolymer. The sealing layer is particularly preferably made of a polyethylene terephthalate copolymer. If the sealable polyester film is sealable on both sides, it preferably also has a sealing layer made of copolyester, in particular of polyethylene terephthalate copolymer, on its bonding side. However, the sealable polyester film is preferably only sealable on one side and has a corona-treated surface on its bonding side to increase its surface energy.The corona-treated surface can be formed by a third layer of polyester or copolyester, in particular polyethylene terephthalate or polyethylene terephthalate copolymer, co-extruded together with the core layer and the sealing layer, or it can be formed by the surface of the core layer facing away from the sealing layer.

[0036] The softer sealing layer compared to the core layer may be a reason why material weakenings formed on the sealing side exhibit a greater fluctuation range of their depth dimension around their mean value.

[0037] The cover layer can, in principle, be formed from any polymer. Preferably, the cover layer is formed from exactly one polymer. Particularly preferably, it consists of exactly one polymer.

[0038] If the top layer is separable from the base layer, for example because the adhesive of an adhesive layer arranged between the top layer and the base layer is solvent-soluble, the top layer can be made of an easily processable polyolefin, such as polypropylene, instead of the polyester material of the base layer. However, if it is necessary to freely select the adhesive of the adhesive layer in order to create a specific adhesion effect between the top layer and the base layer, the use of a polyester top layer is advantageous from the perspective of the desired recyclability of the blister pack formed with the packaging film. The same applies if the top layer and the base layer are to be bonded together by thermal lamination, since compatible materials are then required in the top layer and in the further sealing layer of the polyester film, which is then sealable on both sides.

[0039] In order to achieve the best possible recyclability of the packaging film, the cover layer is therefore preferably made of the same polyester as the base layer, in particular as its core layer.

[0040] To inform consumers about the contents of the blister pack formed with the packaging film, the top layer can bear a print job and / or a protective overprint varnish. Preferably, if the top layer is bonded to the base layer via an adhesive layer, the top layer can be printed either front-to-front or back-to-back. An overprint varnish is preferably present if the top layer is front-to-front printed, in order to protect the print job, which is then initially accessible from the outside, with the overprint varnish, or to make it more durable.

[0041] Preferably, only a portion of the surface of the cover layer is provided with a print job and / or preferably the print job is formed by only a single printing ink in order not to place an excessive burden on the recycling process after use of the blister pack due to printing inks. Printing inks are generally washed off when plastics are recycled in order to obtain a recyclate that is as color-neutral as possible. Preferably, no more than 20% of the surface area of ​​the cover layer is covered with print job. The area covered by the print job is the area that actually bears the print job, so that areas free of print job within letters and characters are considered to be uncovered areas. In principle, it should not be ruled out that the packaging film may comprise further layers in addition to the layers mentioned above.To simplify the manufacturing process, the packaging film preferably consists only of the above-mentioned layers, with the printing application being optional. Further preferably, the packaging film is free of metal foils.

[0042] The present application also relates to a blister pack with a blister carrier and with a packaging film as described and further developed above as a lidding film, wherein the blister carrier has a removal side and a support side opposite the removal side, wherein the blister carrier has at least one product receiving cavity which is designed as a concave depression on the removal side, wherein at least one exposed surface of the blister carrier on the removal side comprises a polyester, wherein the lidding film is connected with its sealing side to the removal side of the blister carrier by thermal sealing, so that the lidding film spans the at least one product receiving cavity in a closing manner in the virgin state of the blister pack.

[0043] To facilitate the recycling of the blister pack, the blister carrier is preferably made of a thermoplastic monolayer material. To ensure the thermal seal between the packaging film and the blister carrier can be easily established, the blister carrier is preferably made of polyester, particularly preferably the same polyester as the base layer, in particular its core layer, thus preferably polyethylene terephthalate.

[0044] The blister carrier is preferably preformed with the at least one product receiving cavity, for example by deep drawing or the like.

[0045] The present invention will be explained in more detail below with reference to the accompanying drawings. Figure 1 shows a roughly schematic cross-sectional view through a first embodiment of a packaging film according to the present invention.

[0046] Fig. 2 is a roughly schematic cross-sectional view through a second embodiment of a packaging film according to the present invention,

[0047] Fig. 3 is a roughly schematic cross-sectional view through a blister pack of the present invention using a packaging film of the first embodiment as a push-through lidding film, and

[0048] Fig. 4 is a roughly schematic cross-sectional view through a blister pack of the present invention using a packaging film of the second embodiment as a push-through lidding film.

[0049] The illustrations in Figures 1 to 4 are not to scale.

[0050] In Figure 1, a first embodiment of a packaging film according to the invention is generally designated 10. The packaging film 10, which is particularly suitable for use as a push-through lidding film, hereinafter also referred to as "push-through film," comprises a one-side sealable polyester film 12 as the base layer 14, wherein the base layer 14 has an exposed sealing side 14a formed by a sealing layer 16 made of a copolyester. The sealing layer 16 is supported by a core layer 18 of the base layer 14 formed of a polyester. The polyester of the core layer 18 is preferably polyethylene terephthalate (PET). The copolyester of the sealing layer 16 is preferably polyethylene terephthalate copolymer (coPET).

[0051] The surface of the base layer 14 opposite the sealing side 14a forms the connecting side 14b, the surface energy of which is increased by a corona treatment in a manner known per se, compared to the surface energy of the unmodified surface.

[0052] On the connecting side 14b, the base layer 14 is arranged with an adhesive layer 20, for example based on polyurethane, with a preferred area-related application weight of 3 g / m 2 in the dry state with a polymer film 22 as a cover layer 24.

[0053] The cover layer 24 can be formed from a polyester, wherein in order to achieve the highest possible purity and to facilitate later recycling of the packaging film 10, the same polyester is preferably used to form the cover layer 24 as is also used to form the core layer 18 of the base layer 14.

[0054] The cover layer 24 can alternatively be formed from a polyolefin, in particular from polypropylene, in which case, to facilitate later recycling of the packaging film 10 or a blister pack formed with its participation (see Figures 3 and 4), an adhesive that can be dissolved by a solvent, such as sodium hydroxide solution, is preferably used in the adhesive layer 20. By dissolving the adhesive layer 20, the cover layer 24 can then be separated as a foreign material from the remaining packaging, which is predominantly made, for example, of at least 95% by weight, of polyester, in particular of PET.

[0055] The base layer 14 has a total thickness with a thickness dimension D in the range of 23 pm to 40 pm, preferably 30 pm. The cover layer 24, in contrast, has a significantly smaller total thickness with a thickness dimension d in the range of 4 pm to 5 pm, particularly preferably 4.5 pm. The thickness dimension d corresponds to the first layer thickness mentioned in the introduction to the description, and the thickness dimension D corresponds to the second layer thickness.

[0056] The cover layer 24 can be printed with printing inks using either a front-to-back or reverse-to-back printing process, for example, with consumer information about the type and quantity of contents packaged using the packaging film 10. In the case of a front-to-back printing application of the cover layer 24 on the surface facing away from the adhesive layer 20, the cover layer 24 is preferably additionally provided with an overprint varnish to protect the print application from external influences, such as abrasion. In the packaging film 10 of the first embodiment, material weakenings 26 in the form of linear mechanical incisions 28 are introduced into the base layer 14 from the sealing side 14a, with a depth dimension T of the material weakenings 26 extending over more than half the thickness dimension D of the base layer 14. The material weakenings 26 ideally have a uniform cross-section along their extension transverse to the plane of the drawing in Figure 1.In reality, the depth dimension T of a material weakening 26 can fluctuate along its length. In the area of ​​extension of the material weakenings 26, the base layer 14 has a residual layer thickness or residual layer thickness of DT reduced by the material weakenings 26 by their respective depth dimension T. The residual layer thickness DT is preferably 7 μm to 9 μm. Provided that the adhesive layer 20 and the cover layer 24 together have a thickness of preferably 6 μm to 8 μm, the residual material thickness of the packaging film 10 in the area of ​​the material weakenings 26, without taking a print job into account, is preferably 13 μm to 17 μm.

[0057] In the example shown, the material weakenings 26 do not run orthogonally to the plane of the drawing in Figure 1, but obliquely, but in a plane orthogonal to the plane of the drawing in Figure 1 and parallel to the base layer 14.

[0058] Due to the material weakenings 26, the strength of the material cohesion of the base layer 14 and the packaging film 10 is reduced overall to such an extent that the packaging film 10 can be locally broken through by locally exerting force on the sealing side 14a of the base layer 14 and thus the packaging film 10.

[0059] The cover layer 24 increases the strength of the packaging film 10 to such an extent that the mechanical and dynamic forces acting on the base layer 14 and later the packaging film 10 during its production and during the production of a blister pack do not lead to local damage to the packaging film 10. However, due to the small thickness d of the cover layer 24, the increase in strength caused by its lamination is so small that the puncture resistance of the packaging film 10 is still maintained. The adhesive layer 20 between the cover layer 24 and the core layer 18 of the base layer 14 advantageously acts as a load buffer, which distributes forces acting selectively on the cover layer 24 over a larger effective area on the base layer 14, which advantageously improves the processability of the packaging film 10.

[0060] Preferably, both the polymer film 22 of the cover layer 24 and at least the core layer 18 of the sealable polyester film 12 of the barrier layer 14 are stretched, preferably biaxially stretched, in order to achieve the same material strength with a lower material thickness.

[0061] Figure 2 shows a second embodiment of the packaging film 110 in the same roughly schematic cross-sectional view as Figure 1. Identical and functionally identical components and component sections as in the first embodiment of Figure 1 are provided with the same reference numerals in the second embodiment of Figure 2, but increased by the number 100. The second embodiment will be described below only insofar as it differs from the first embodiment. Otherwise, for an explanation of the second embodiment, express reference is made to the description of the first embodiment.

[0062] The embodiment of Figure 2 differs from the embodiment of Figure 1 only in that the material weakenings 126 are introduced into the base layer 114 not from the sealing side 114a, but from the connecting side 114b. Accordingly, in the second embodiment of the packaging film 110, the sealing layer 116 of the base layer 114 is undamaged, in contrast to the first embodiment.

[0063] The adhesive of the adhesive layer 120, which is applied in a flowable manner between the base layer 114 and the cover layer 124, can penetrate slightly into the material weakenings 126. Whether this occurs depends on the size and shape of the material weakenings 126 and the viscosity of the applied adhesive. The material weakenings 26 and 126 are introduced into the base layer 14 and 114, respectively, using a knife roller, for example. The knife roller carries blades that essentially correspond to a positive shape of the material weakenings 26 and 126. The base layer 14 or 114 is guided past the knife roller with the surface to be weakened facing the knife roller. A counter roller presses the base layer 14 or 114 against the knife roller and thus causes the blades carried by the knife roller to cut into the base layer 14 or 114.

[0064] In the first embodiment, the base layer 14 can be guided past the knife roller alone or in conjunction with the cover layer 24 laminated by the adhesive layer 20 to form the material weakenings 26. In the second embodiment, the base layer 114 alone must be guided past the knife roller to form the material weakenings 126, since the connecting side 114b of the base layer 114 is no longer accessible after the cover layer 124 has been laminated.

[0065] In both embodiments, the material weakenings 26 and 126 on the finished blister pack are not accessible to consumers and to external influences such as contamination and the like.

[0066] Figure 3 shows a roughly schematic cross-sectional view of a first embodiment of a blister pack 30, which is formed with the packaging film 10 of the first embodiment as a push-through film 32 of the blister pack 30.

[0067] The blister pack 30 comprises a blister carrier 34, which is preferably designed as a single-layer monofilm for recycling purposes. The thickness ratios of the push-through film 32 and the blister carrier 34 are also not to scale.

[0068] The blister carrier 34 is preferably made of polyester, particularly preferably of the same polyester from which the core layer 18 of the push-through film 32 is made, thus preferably PET in the present case. Although the blister carrier 34 can have a sealing layer on its removal side 34b to increase the strength of the bond with the packaging film 10 or push-through film 32, this is not necessary. The sealing layer 16 made of copolyester can seal directly with the polyester of the blister carrier 34.

[0069] By deep drawing, at least one product receiving cavity 36 is formed in the blister carrier 34, in which a product 38, for example, a tablet, a capsule, or another rigid object such as chewing gum or a tool insert, is received. The product receiving cavity 36 is completely covered by the push-through film 32. The push-through film 32 is permanently connected to the removal side 34b by heat sealing.

[0070] With its support side 34a, the blister carrier 34 can rest on a surface, such as a table or a shelf, and be made available for use.

[0071] The blister carrier 34 is flexible in a manner known per se such that by exerting force on the border of the product receiving cavity 36 on the support side 34a, the product 38 received in the product receiving cavity 36 can be pressed against the push-through film 32 exposed in the region of the product receiving cavity 36. The force thus exerted on the sealing side 14a of the push-through film 32 can cause the push-through film 32 to tear above the product receiving cavity 36 due to the material weakenings 26, and thus the product 38 can be removed on the removal side 34b of the blister carrier 34 through the locally opened push-through film 32.

[0072] Figure 4 shows a second embodiment of a blister pack 130. Identical and functionally equivalent components and component sections as in the first embodiment of Figure 3 are provided in Figure 4 with the same reference numerals as in Figure 3, but increased by the number 100.

[0073] The second embodiment of the blister pack 130 will be described below only insofar as it differs from the first embodiment of the blister pack 30. Otherwise, for an explanation of the second embodiment, express reference is made to the description of the first embodiment.

[0074] The second embodiment of the blister pack 130 differs from the first embodiment in that the push-through film 132 is formed by the packaging film 110. The continuously closed sealing layer 116, which is not damaged by material weakenings 126, is again permanently connected to the blister carrier 132 by heat sealing.

Claims

Claims 1. Packaging film (10; 110), in particular for a blister pack (32; 132), comprising: a polymer film (22; 122) as cover layer (24; 124) with a first layer thickness (d), and a sealable polyester film (12; 112) as base layer (14; 114) with a second layer thickness (D), wherein the base layer (14; 114) is designed for heat-sealing connection to a compatible plastic surface, wherein the base layer (14; 114) has an exposed sealable sealing side (14a; 114a) and a connection side (14b; 114b) facing the cover layer (24; 124), wherein the second layer thickness (D) is greater than the first layer thickness (d), wherein the base layer (14; 114) has local material weakenings (26; 126) which do not completely penetrate the base layer (14; 114) in the thickness direction, wherein the base layer (14; 114) in the extension area of ​​the material weakenings (26; 126) is, compared to an unweakened base layer area without material weakenings (26;126), has a lower second layer thickness (DT).; 2. Packaging film (10) according to claim 1, characterized in that the local material weakenings (26) are formed on the sealing side (14a).

3. Packaging film (110) according to claim 1 or 2, characterized in that the local material weakenings (126) are formed on the connecting side (114b).

4. Packaging film (10; 110) according to one of the preceding claims, characterized in that the cover layer (24; 124) has a first layer thickness (d) in the range from 3.5 to 6 pm.

5. Packaging film (10; 110) according to one of the preceding claims, characterized in that the base layer (14; 114) has a second layer thickness (D) in the range from 20 to 33 pm.

6. Packaging film (10; 110) according to one of the preceding claims, characterized in that the packaging film (10; 110) comprises an adhesive layer (20; 120) arranged between the cover layer (24; 124) and the base layer (14; 114), which adhesive layer connects the base layer (14; 114) and the cover layer (24; 124) to one another.

7. Packaging film (10; 110) according to claim 6, characterized in that the adhesive layer (20; 120) has a surface-related application weight in the range of 1.5 to 5.0 g / m 2 has.

8. Packaging film (10; 110) according to one of claims 1 to 5, characterized in that the sealable polyester film (12; 112) of the base layer (14; 114) is a double-sided sealable polyester film which is also sealable on the connecting side, wherein the cover layer (24; 124) is thermolaminated to the base layer (14; 114) by means of the sealable connecting side of the sealable polyester film.

9. Packaging film (10; 110) according to one of the preceding claims, characterized in that the cover layer (24; 124) and / or the base layer (14; 114) are formed from oriented polymer.

10. Packaging film (10; 110) according to claim 9, characterized in that the cover layer (24; 124) and / or the base layer (14; 114) are formed from biaxially oriented polymer.

11. Packaging film (10; 110) according to one of the preceding claims, characterized in that the cover layer (24; 124) is formed from a polyolefin or from a polyester.

12. Packaging film (10; 110) according to claim 11, characterized in that the cover layer (24; 124) is formed from polypropylene or from the same polyester as the base layer (14; 114).

13. Packaging film (10; 110) according to one of the preceding claims, characterized in that the cover layer (24; 124) carries a print application and / or a protective overprint varnish.

14. Packaging film (10; 110) according to one of the preceding claims, characterized in that the packaging film (10; 110) consists only of the layers (14, 20, 24; 114, 120, 124) mentioned in at least one of the preceding claims.

15. Blister pack (30; 130) with a blister carrier (34; 134) and with a packaging film (10; 110) according to one of the preceding claims as a lidding film (32; 132), wherein the blister carrier (34; 134) has a removal side (34b; 134b) and a support side (34a; 134a) opposite the removal side (34b; 134b), wherein the blister carrier (34; 134) has at least one product receiving cavity (36; 136) which is formed as a concave depression on the removal side (34b; 134b), wherein at least one exposed surface of the blister carrier (34; 134) on the removal side (34b; 134b) comprises a polyester, wherein the lidding film (32; 132) with its sealing side (14a; 114a) is connected by thermal sealing to the removal side (34b; 134b) of the blister carrier (34; 134), so that the lidding film (32; 132) in the virgin state of the blister pack (30; 130) spans the at least one product receiving cavity (36; 136) in a closing manner.

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