Blister closure film and blister pack, and method for the production thereof

Abstract

The invention relates to a blister closure film comprising a first plastic which is joined to a nonwoven, the fibres of which contain a second plastic which is based predominantly on the same polymers / copolymers as the first plastic. Furthermore, the invention relates to a blister pack comprising a blister base film and such a blister closure film. Moreover, the invention relates to a method for producing a blister closure film by providing a nonwoven which comprises a second plastic, providing a first plastic which is based predominantly on the same polymers / copolymers as the second plastic, and joining the nonwoven to this first plastic.

Description

[0001] Blister sealing film and blister packaging and process for their production

[0002] Description

[0003] The invention relates to a blister sealing film comprising a first plastic. Furthermore, the invention relates to a blister pack comprising a blister base film and such a blister sealing film. Furthermore, the invention relates to a method for producing a blister sealing film.

[0004] Sensitive products that are packaged individually or in small quantities are often presented in blister packs. As the term "blister" suggests, the first part of such packaging forms a cavity that can accommodate the product to be packaged. A second part of the packaging covers the opening of the cavity, so that the product contained in the blister is completely enclosed. The second part of the packaging often contains information about the product inside.

[0005] The first part of the packaging is often transparent so that the customer can see and visually assess the product inside. Such designs are frequently used, for example, for electrical items such as light bulbs, chargers, cables, memory cards and flash drives; for hygiene products such as toothbrushes; for office supplies such as pens, printer cartridges, adhesive tapes and glue; for food products such as meat, fish and sweets; for laboratory equipment; and for medical and pharmaceutical products such as ampoules, tablets, syringes, cannulas and bandages. In these cases, the second part of the packaging is often paper or plastic. For the separate disposal of the packaging material, it is often sufficient with these designs to completely remove the second part of the packaging from the first part and to dispose of both parts separately.If both parts of the packaging are made of the same material, for example the same type of plastic, they can be disposed of together.

[0006] For some sensitive, particularly light-sensitive, products such as medicines, hygiene products, and laboratory supplies, an opaque first part of the packaging is preferred. For such sensitive products, air diffusion, which can occur through some plastics and paper, should also be avoided. Therefore, the second part of the packaging often comprises an aluminum foil sealed against the first part of the packaging.

[0007] In the production of such packaging and the packaging of the products, thermoforming films (also known as blister base films) are usually used (e.g. made of PVC), into whose recess(es) the product(s) are placed. All cavities are then sealed flat with an (e.g. partially printed) aluminum foil. This is done, for example, by plate or roller sealing. The first part of the packaging (the blister) is bonded to the second part of the packaging (the blister closure film or blister cover film). Blister cards containing a predetermined number of products are then typically punched out of the blister base film sealed with the blister closure film and subjected to secondary packaging.

[0008] With such blister packaging, the end consumer typically gains access to the product by pushing the product (e.g., a tablet) through the blister lidding film. This causes the blister sealing film to tear locally, allowing the product to be pushed out of the packaging through the tear and become accessible. Blister lidding films made of (preferably hard) aluminum have proven particularly suitable in the past. These allow the product to be easily pushed through, and the aluminum foil, due to its good thermal conductivity and temperature resistance when exposed to heat during a sealing process, is particularly easy to handle and allows for high packaging performance. However, one problem with such blister packaging is its recycling.The materials used are typically sealed against each other across their entire surface and are not separated at all, or at least not completely, when the product is removed. Rather, the (metal-containing) blister sealing film usually remains completely bonded to the plastic of the blister base film, and the product is removed simply through a tear in the blister sealing film. Accordingly, the plastic of the blister base film and the (usually metal-containing) blister sealing film are disposed of together. Because the materials of the blister packaging are mixed, separate recycling is either not possible or only possible with increased effort. For this reason, state-of-the-art blister packaging is not recycled in most cases.

[0009] Attempts have been made in the past to provide blister sealing film based on the same plastic as the blister base film. To enable the blister sealing film to be torn open under pressure from the end customer, it was suggested that the blister sealing film be provided with predetermined breaking points. For this purpose, the blister sealing film was scored on one side. However, this is extremely difficult, especially with large-format films, as the depth of the score must be precisely controlled across the entire working width to ensure, on the one hand, a specified tear strength of the packaging film and, on the other hand, a sufficient local weakening of the puncture resistance.

[0010] Other attempts have involved mechanically weakening a plastic material used in the blister sealing film by adding mineral additives. However, such packaging also has the disadvantage that the mineral additives impart foreign substances to the plastic, making it difficult to recycle. The additives can also pose a health risk and / or react with ingredients in the product being protected by the blister packaging. This is particularly risky and undesirable for high-quality and sensitive products such as pharmaceuticals. Furthermore, the puncture resistance of such films is, at least in some cases, neither precisely controllable nor does it exhibit the stress profile desired for blister packaging, in which the force required to deform it steadily increases until the film tears.

[0011] Accordingly, the object of the present invention is to provide a blister closure film which can be recycled together with the blister base film, preferably under usual recycling conditions, and which can also be opened in a similar way to a metal-containing blister closure film.

[0012] This object is achieved according to the features of patent claim 1. Further advantageous embodiments are the subject of the dependent patent claims.

[0013] A key aspect of the invention is that a blister closure film according to the invention comprises a first plastic, wherein this first plastic is bonded to a nonwoven whose fibers contain a second plastic based predominantly on the same polymers / copolymers as the first plastic. Surprisingly, it has been found that a combination of a nonwoven and a plastic exhibits properties similar to those of known metal-containing blister closure films. Like metal-containing blister closure films, at least preferred embodiments of a blister closure film according to the invention are printable.

[0014] In a preferred embodiment, the first plastic is composed of two or more plies and / or layers. Preferably, one of these layers is a film, particularly a coextruded film. This film is preferably made of EVOH.

[0015] Preferably, a metallization is further provided and preferably this metallization is arranged on the above-mentioned film.

[0016] The plastic preferably has a further layer, in particular a tie layer. This further layer is arranged in particular on the metallization or on the film.

[0017] Preferably, a further layer is provided, which consists in particular of HDPE. This further layer is preferably arranged on the tie layer.

[0018] In a preferred embodiment, the blister closure film is pushable and in particular pushable by a user. In a further preferred embodiment, the blister closure film is not peelable and / or cannot be removed (in particular from other components of a package). Preferably, the blister closure film cannot be peeled or removed in one piece. Preferably, the first plastic and the second plastic are based on the same polymers / copolymers to an extent of at least 70 percent by weight, preferably > 80 percent by weight, more preferably > 90 percent by weight, especially preferably > 95 percent by weight. Due to the high proportion of plastics based on identical polymers / copolymers, recycling is particularly efficient and easy.For the purposes of this invention, plastics based on the same polymers / copolymers are understood to mean those whose polymer chains comprise repeating units at least to the extent specified above. It is not necessary that these repeating units were actually produced from identical monomers. Rather, they also include plastics whose repeating units were obtained, for example, by linking oligomers. Due to the high proportion of identical repeating units in polymers of plastics, (separate) processing is particularly easy during recycling.

[0019] The blister closure film preferably comprises a first plastic and a second plastic which are selected from a group comprising polyethylene (PE), polypropylene (PP), polystyrene (PS), polyester, including preferably polylactide (PI_A), polyethylene terephthalate (PET) or polycarbonate (PC), ethylene-vinyl alcohol copolymer (EVOH) and mixtures thereof. These plastics are particularly preferred because established and cost-effective recycling processes are known for them. Accordingly, plants already exist in which these plastics can be sorted out from a mixture of plastic waste and processed. In particular, given the above-mentioned high proportion of identical repetitive units in the polymers of the two plastics (namely the first and the second plastic), it is possible to process these polymers separately and reuse them.

[0020] Preferably, the thickness of the first plastic and / or the nonwoven fabric of the blister closure film is selected such that the puncture resistance of the blister closure film, measured in accordance with DIN EN ISO 14477 using a mandrel with a diameter of 10.5 mm, essentially corresponds to the puncture resistance of a 20 μm thick aluminum foil. In this context, essentially corresponding to the puncture resistance of a 20 μm thick aluminum foil should be understood to mean that the puncture resistance of the blister closure film, measured in accordance with DIN EN ISO 14477 using a mandrel with a diameter of 10.5 mm, deviates by < 30%, preferably < 20%, from the puncture resistance of a 20 μm thick aluminum foil. As a result, for a user, opening a blister pack with a blister closure film as described above can be particularly similar to opening a blister pack with a metal-containing blister closure film, for example an aluminum foil.The user does not need to adapt to a different opening method or use tools. This is particularly advantageous when the blister sealing foil is used to seal a blister pack for medications, as these often have to be opened by patients who are not at full physical strength.

[0021] Preferably, the thickness of the first plastic and / or the nonwoven fabric of the blister closure film is selected such that the puncture resistance of the blister closure film, measured in accordance with DIN EN ISO 14477 using a mandrel with a diameter of 10.5 mm, is in a range of 15 - 50 N, preferably 20 - 35 N, particularly preferably in the range of 25 - 30 N. With this embodiment of the blister closure film, it can be ensured, on the one hand, that a product packaged in a blister pack with a blister closure film as described above is securely protected, but on the other hand, opening by breaking open the blister closure film can be carried out sufficiently easily for a user and preferably without tools (or with the aid of the packaged product as a tool for opening the blister closure film, for example by pushing through).

[0022] If it is desired to make the blister sealing film particularly puncture-resistant, for example, to provide child-resistant blister packaging, it is preferable to provide the blister sealing film with an additional plastic layer. Alternatively or additionally, the thickness of the first plastic layer and / or the nonwoven fabric can be increased to achieve or support this effect.

[0023] The behavior of mineral fillers in a polymer-based blister sealing film under pressure has proven particularly disadvantageous in the prior art use of mineral fillers. Due to the mineral additives, it often happens that when pressure is applied by a user, the force required to deform the blister sealing film until it tears open does not increase continuously, but rather passes through a maximum. Therefore, the maximum force required for deformation of the blister sealing film required for tearing does not have to be applied. This property is described in detail in connection with Fig. 4.This property of the polymer-based blister sealing film containing mineral fillers is particularly disadvantageous because, when opening the blister, the user may not recognize the point of maximum force / pressure required for deformation, or may not be able to reduce the force / pressure in time before opening the blister sealing film. This causes the blister sealing film to suddenly tear open, and the contents are often ejected from the blister pack due to the excessive pressure. This is particularly disadvantageous for sensitive and / or high-priced contents, such as medications, and often results in the contents being unusable.

[0024] Therefore, a preferred variant of the blister closure film is characterized in particular by the fact that a force acting on the blister closure film, preferably when testing the puncture resistance of the blister closure film in accordance with DIN EN ISO 14477 using a mandrel with a diameter of 10.5 mm, increases monotonically, preferably strictly monotonically, until the force required for puncture is reached. It is not absolutely necessary, and with some polymers not achievable with reasonable effort, that the force required for puncture increases linearly and / or strictly monotonically. The terms “monotonic increasing” and “strictly monotonically increasing” should therefore be understood in their mathematical meaning. Accordingly, with a strictly monotonic increase, the force / pressure required for deformation must increase with increasing deformation of the blister closure film.Areas where increasing deformation of the blister sealing film is possible without a further increase in the required force / pressure are excluded with this variant. In contrast, with a monotonic increase, the only requirement is that with increasing deformation of the blister sealing film, the force / pressure required for deformation in the area under consideration never decreases until the blister sealing film tears. However, areas where increasing deformation of the blister sealing film is possible without a further increase in the required force / pressure are possible with this variant.

[0025] In a preferred embodiment, the blister closure film has a sealable layer which, preferably at a sealing temperature in the range of 100 - 170°C, preferably 110 - 160°C, more preferably 120 - 150°C, particularly preferably 130 - 140°C, has a seal seam strength of > 6 N / 15 mm, preferably > 9 N / 15 mm, particularly preferably > 12 N / 15 mm compared to a test specimen comprising the first plastic. This embodiment enables the blister closure film to be sealed sufficiently tightly and securely to the blister base film under normal sealing conditions. Even when the blister pack is opened, with a seal seam strength in the range described above, the blister closure film tears in the area of ​​pressure application without detaching from the blister base film in the sealed areas.

[0026] The sealable layer is preferably a layer comprising the first plastic. A special sealing layer or sealing wax, as is usually required in the blister closure films known from the prior art when using different materials, is therefore not necessary. A blister closure film therefore preferably has no additional sealing layer on the surface of the first plastic facing away from the nonwoven. This means that the blister closure film can comprise even fewer foreign materials and can therefore be particularly light. Such a blister closure film preferably has a basis weight that is at least 20%, preferably at least 30%, and particularly preferably at least 40% lower than the basis weight of the blister closure films with mineral fillers known from the prior art. The blister closure film preferably has a basis weight that is in the range of 15 - 200 g / m2 , preferably 18 - 60 g / m 2 and ideally 20 - 40 g / m 2 lies.

[0027] Preferably, a sealing layer is arranged on and / or against the nonwoven fabric. It is possible for a nonwoven fabric, such as a PE nonwoven fabric, to be sealed directly against the PE-based floor.

[0028] In another embodiment, a coating, such as a PE copolymer, is applied to the nonwoven. This design allows for lower sealing temperatures to be achieved.

[0029] The first plastic is preferably in the form of a film, preferably as one or more moldable films. A moldable film is typically characterized by its high puncture resistance. However, when combined with a nonwoven fabric, the puncture resistance is significantly reduced, making the resulting blister seal film easy for a user to open. The material of the nonwoven fabric is preferably the same or at least sufficiently similar to the first plastic. This similarity or similarity ensures that the composite softens at a predetermined temperature and thus becomes sealable.

[0030] A blister closure film has proven particularly advantageous in which the nonwoven fabric is bonded to a layer of the first plastic on at least one side, preferably exactly one side, or alternatively both sides, preferably using a hotbonding process. In this embodiment, the nonwoven fabric thus forms a layer or ply that is bonded to a layer or ply of the first plastic on at least one of its large-area side surfaces. The first plastic and / or an adhesive can also penetrate into or be arranged in spaces formed between the fibers of the nonwoven fabric. In some cases, the penetration of the first plastic and / or the adhesive is even preferred in order to achieve improved adhesion between the nonwoven fabric and the first plastic.

[0031] Preferably, the nonwoven fabric is bonded to a layer of the first plastic on both sides, since in this embodiment, the blister seal film has a (at least macroscopically) flat surface on both sides, which is, for example, printable. A flat surface is also preferred on the side facing the contents to prevent mechanical (or chemical) interaction between the nonwoven fabric fibers and the contents.

[0032] In a preferred embodiment, the composite is a composite of a nonwoven and a plastic sheet, wherein the nonwoven preferably seals directly.

[0033] In addition, designs composed of plastic / nonwoven / plastic are also conceivable, with the inner plastic preferably being directly sealed in one design. This plastic (especially the inner one) could also be provided with a sealing coating.

[0034] In a preferred embodiment of the blister closure film, the nonwoven fabric comprises stretched fibers and / or the first plastic is uni- or bidirectionally stretched. The use of stretched fibers in the nonwoven fabric has proven particularly advantageous because further stretching of the fibers is only possible to a limited extent and therefore the force required to tear the blister closure film can be adjusted relatively easily. Preferably, the individual fibers are pre-stretched almost to their maximum. This severely limits the further extensibility of the nonwoven fabrics. When subjected to force, the fibers preferably tear after an additional stretching or elongation of between 20 and 300%, preferably between 50 and 200% and particularly preferably between 70 and 120%.

[0035] Furthermore, the use of stretched fibers in the nonwoven fabric can provide the advantage that a force acting on the blister sealing film essentially leads to a deformation of the first plastic, and the fibers of the nonwoven fabric change almost exclusively in their relative arrangement to one another, but significantly in their length. Accordingly, the force required to tear open the blister sealing film can be essentially determined by the force required to tear the (stretched) fibers of the nonwoven fabric. If the fibers tear, the tear propagates, and the first plastic also tears.

[0036] Preferably, the fleece has a grammage in the range of 7 - 100 g / m 2 , preferably 8 - 50 g / m 2 , particularly preferably 10 - 20 g / m 2 on.

[0037] Preferably, the choice of the first plastic and / or the thickness and / or grammage of the first plastic can influence the gradient of the force required to deform the blister sealing film (in a force / deformation diagram). A greater thickness and / or grammage of the first plastic, with identical properties of the nonwoven, preferably leads to a greater gradient of the force required to deform the blister sealing film in a diagram as described above (see also Fig. 5).

[0038] Another essential aspect of the present invention is a blister pack comprising a blister base film and a blister closure film as described above. Such a blister pack can preferably be recycled using conventional equipment and is easy to open for end users. At the same time, the contents enclosed by the blister pack are securely protected (until opened by the end user).

[0039] In a preferred embodiment of such a blister pack, the blister base film and the blister closure film are each made of at least 80 percent by weight of a plastic, with these plastics being based on at least 70 percent by weight of the same polymers / copolymers. This further simplifies recycling, as residues of the blister closure film that remain attached to the blister base film after opening can also be recycled together with it.In order to further simplify recycling and reduce contamination, it is preferred that the blister base film and the blister closure film each consist of > 90 percent by weight, more preferably > 95 percent by weight, particularly preferably > 98 percent by weight of a plastic, wherein these plastics are preferably based on the same polymers / copolymers at least to the extent of > 80 percent by weight, more preferably > 90 percent by weight, particularly preferably > 95 percent by weight.

[0040] Mineral fillers known from the prior art are preferably absent in this embodiment, or at least reduced to a level where they can be considered contaminants. Their proportion is preferably well below 10 percent by weight, such as <5 percent by weight, preferably <3 percent by weight, particularly preferably <1 percent by weight. The problems that arise when recycling plastics with mineral fillers can thus be avoided.

[0041] Preferably, a blister pack as described above is a blister pack for electrical items, such as electrical items from a group that includes lamps, chargers, cables, batteries, rechargeable batteries, headphones, microphones, memory cards and flash drives; for hygiene products, such as hygiene products from a group that includes toothbrushes, attachments for electric toothbrushes, dental floss, earplugs, tweezers, mascara, make-up, eyeliner, lipsticks, brushes, nail scissors, cuticle scissors, air fresheners, pacifiers, razors, cleaning and descaling tablets; for office supplies, such as office supplies from a group that includes pens, sharpeners, printer cartridges, adhesive tapes, glue, erasers, staples and paint rollers; for foodstuffs, such as foodstuffs from a group that includes chewing gum, meat, fish - ready meals, sweets and chocolates; for laboratory equipment, such as laboratory equipment from a group,which includes ampoules, tablets, syringes, cannulas, bandages, pipettes, pipette tips, spatulas, thermometers, spoon spatulas, stoppers, (screw or crimp) caps, sample containers and cuvettes, for medical and / or pharmaceutical products such as medical and / or pharmaceutical products from a group that includes tablets, syringes, cannulas, (fever) thermometers, ampoules, aerosol dispensers and bandages, for animal supplies such as animal supplies from a group that includes pet food, bones, pet toys, tick tweezers and cards, for craft supplies such as craft supplies from a group that includes tools, pliers, screwdrivers, screws, nuts, nails, cable ties, drills, bits, saw blades, cutting discs, abrasives, planes, magnets, dowels, hooks, eyelets, washers, springs, hose clamps, angle brackets, hinges, felt pads, (sewing) needles,as well as fishing and angling products and / or for toys, such as toys from a group that includes vehicle models, trading cards, (water) pistols, ammunition for toy pistols, (dart) arrows, figures, play money, key rings, balls, marbles, beads, and craft supplies. Such blister packaging has proven particularly advantageous for the above-mentioned goods and product groups, as these are offered in large quantities in previously known blister packaging, thus simplifying the recycling of large quantities of packaging and / or allowing these goods to be stored, kept, and offered particularly safely yet easily accessible in blister packaging as described above.

[0042] The type of plastic is preferably adapted to the product to be packaged in the blister pack. For example, if products sensitive to radiation of a specific wavelength are to be contained in a blister pack, it is preferred that a plastic with low permeability to radiation of this wavelength be used for the blister pack and / or the blister sealing film. Optionally, the plastic can contain one or more additives to (further) reduce the permeability to radiation of this wavelength. Such a design is particularly preferred for light-sensitive products such as medicines, hygiene products, and / or laboratory materials.

[0043] Additionally or alternatively, a blister closure film has at least one barrier property against a substance and / or radiation harmful to the contents. In particular, it is preferred that the blister closure film has a barrier property against a substance or radiation selected from a group comprising water, a gas, light, MOSH, MOAH, phthalates, and other migration substances. The barrier property preferably reduces the amount of substance or radiation penetrating through the blister closure film by at least 90%, preferably at least 95%, more preferably at least 98%, especially preferably at least 99%, and most preferably at least 99.9%. This barrier property of the blister closure film can be achieved by a polymer contained in the first and / or second plastic.If the barrier properties of the blister sealing film are insufficient despite the selection of a suitable polymer, one or more additives can be added to the plastic to achieve the desired barrier properties. For example, pigments could be added that absorb radiation of a wavelength harmful to the contents to be protected.

[0044] Additionally or alternatively, it is also conceivable to adjust the desired barrier properties of the blister sealing film using an organic and / or inorganic coating. This variant has the advantage that the barrier properties can be adjusted using a very thin coating, and according to current standards, this does not negatively impact the recycling properties. In a preferred embodiment, the organic and / or inorganic coating is applied to the second plastic.

[0045] The present invention further relates to a method for producing a blister sealing film, in particular a blister sealing film as described above. The method according to the invention is characterized by the steps

[0046] Providing a fleece comprising a second plastic,

[0047] Providing a first plastic which is predominantly based on the same polymers / copolymers as the second plastic, and

[0048] - Connecting the fleece with this first plastic.

[0049] This process makes it particularly easy to produce a blister sealing film whose property profile and applicability are similar to those known from the state of the art, particularly metal-containing blister sealing films, but which is significantly easier to recycle using currently available equipment, both simple and cost-effective. This can be explained in particular by the fact that particularly similar plastics based on the same polymers / copolymers are used for the nonwoven fabric with the second plastic and the first plastic, which can be recycled together.

[0050] Preferably, the nonwoven fabric is bonded to a layer of the first plastic on at least one side, preferably exactly one side, alternatively both sides. This creates a strong bond between the nonwoven fabric and the plastic. Preferably, such a bond is thermally stable, so that at least during a heat-sealing process the bond between the nonwoven fabric and the first plastic does not break, or the first plastic does not detach from the nonwoven fabric. A layer of the first plastic attached to the nonwoven fabric also offers the advantage that such a layer does not have the fiber structure of the nonwoven fabric on a visible side and is therefore particularly suitable for post-treatment. Such post-treatment can, for example, involve printing and / or embossing. Both printing and embossing are more visible on a visible side that is less heavily structured than the nonwoven fabric.

[0051] For example, printing or embossing may include product information such as product name, manufacturer name, date of manufacture, product number, production date, production location, production shift, quality control number, security features, expiration date and / or combinations thereof.

[0052] Regardless of whether a print is present or not, a preferred embodiment of a blister sealing film is also provided, which comprises at least one additional layer. This layer is, for example, a lacquer layer. Such a lacquer layer can serve, for example, as a protective lacquer. For example, a lacquer layer could protect a print and / or a security feature. However, it is also conceivable that the lacquer serves to refine the blister sealing film. This refinement can, for example, be visually and / or haptically perceptible.

[0053] In addition to or as an alternative to the variant described above in which the fleece is connected to a layer of the first plastic on at least one side, preferably exactly one side, or alternatively both sides, it is also conceivable and preferred in some process variants for the fleece to be connected to a layer of the first plastic on at least one side, preferably exactly one side, or alternatively both sides, using the hotbonding process. Just like lamination, the hotbonding process can also be used to create a firm bond between the fleece and the plastic. Such a bond is preferably thermally stable so that at least during a heat-sealing process the bond between the fleece and the first plastic is not broken or the first plastic does not detach from the fleece.A layer of the first plastic applied to the nonwoven using the hot-bonding process offers the further advantage that such a layer does not have the fiber structure of the nonwoven on the visible side, making it particularly suitable for post-treatment. Such post-treatment can include printing and / or embossing, for example. Both printing and embossing are more visible on a visible side that is less heavily structured than the nonwoven.

[0054] Another possible variant is one in which a layer of the first plastic is laminated to one side of the nonwoven fabric, and a layer of the first plastic is bonded to the other side of the nonwoven fabric using a hot-bonding process. This allows for particular flexibility regarding the properties of the applied layers.

[0055] In another process variant, the fleece or the first plastic is provided with a sealable layer.

[0056] The blister sealing film is preferably applied to a blister base film and preferably bonded to it. In particular, it is preferred that the blister sealing film be sealed to the blister base film. The blister pack is preferably closed in the process. A product previously placed in a recess in the blister base film is thus enclosed by the blister pack. This allows a sealed blister pack to be produced in a particularly simple manner, and the product contained within is securely protected.

[0057] Further advantages and embodiments can be seen from the attached drawings:

[0058] Showing:

[0059] Fig. 1 is a schematic representation of a blister pack according to the invention with blister sealing film;

[0060] Fig. 2 shows a further embodiment of a blister pack according to the invention with blister sealing film;

[0061] Fig. 3 is a schematic representation of the results of a measurement of the puncture resistance of a blister sealing film known from the prior art, measured in accordance with DIN EN ISO 14477 using a mandrel with a diameter of 10.5 mm;

[0062] Fig. 4 is a schematic representation of the results of a measurement of the puncture resistance of another blister sealing film known from the prior art, measured in accordance with DIN EN ISO 14477 using a mandrel with a diameter of 10.5 mm;

[0063] Fig. 5 a comparative representation of the results of a measurement of the puncture resistance of a known metal-containing blister sealing film (A) and a blister sealing film according to the invention (B) measured in accordance with DIN EN ISO 14477 with a mandrel with a diameter of 10.5 mm.

[0064] Figure 1 shows a schematic representation of a blister pack 10 according to the invention with a blister sealing film 1. The blister pack 10 has a blister base film 5, which in the example shown has several recesses for receiving a filling material (not shown) to be packaged. The openings of these recesses can be closed by a blister sealing film 1.

[0065] In the example shown, the blister closure film 1 consists of a composite comprising a nonwoven fabric 2 and a cover layer 3. The nonwoven fabric 2 is arranged on the side of the blister closure film 1 facing the contents. The cover layer 3 is accordingly arranged on the side of the blister closure film 1 facing away from the contents. This enables the visible side of the blister pack 10 not to be formed by the nonwoven fabric 2 and thus not to have the structure predetermined by the fibers of the nonwoven fabric 2. Rather, the visible side of the blister closure film 1 is preferably formed by the plastic layer 3 or cover layer 3. It preferably has no macroscopically perceptible structure or at least a significantly smaller structure than the nonwoven fabric 2. As a result, this side has a pleasant feel for a user and is preferably printable. The cover layer 3 can be arranged directly or indirectly on the nonwoven fabric 2.In a direct arrangement, the cover layer 3 comprises at least one further (plastic) layer. The cover layer itself, as mentioned, can also have multiple layers and / or consist of multiple layers.

[0066] The blister closure film 1 and the blister base film 5 preferably comprise plastics that are composed of identical polymers / copolymers and / or in which the polymers / copolymers are linked to one another via identical chemical bonds. For example, it is conceivable in this regard that both the blister closure film 1 and the blister base film 5 are based on polyethylene. However, the plastics can differ in some (chemical and / or physical) properties. For example, the (average) chain length of the polymers of the blister closure film 1 and the blister base film 5 can be different. Analogously, individual layers 2, 3, 4 of the blister closure film 1 can also differ in their chemical and / or physical properties.Embodiments are also conceivable in which the polymers / copolymers are at least partially different, but the bonds of the polymers / copolymers to one another in the blister closure film 1 (and / or its individual layers) and the blister base film 5 are identical. It is conceivable in this regard that all bonds are ester bonds, but the respective polyesters differ, for example, a polylactide (PLA) on the one hand and a polyethylene terephthalate (PET) on the other.

[0067] Figure 2 shows a further embodiment of a blister pack 10 according to the invention with blister sealing film 1. In contrast to the embodiment shown in Fig. 1, the blister sealing film 1 is constructed from more than two layers. In the example shown, the blister sealing film 1 has a three-layer structure. In the example shown, a further plastic layer 4 is arranged between the nonwoven 2 and the cover layer 3. This plastic layer can serve, for example, to improve the bond between the nonwoven 2 and the cover layer 3. This layer 4 preferably also comprises a plastic that can be recycled together with the plastic of the nonwoven layer 2 and the cover layer 3.

[0068] Figures 3 and 4 each show schematic representations of the results of measurements of the puncture resistance of a blister closure film known from the state of the art, measured in accordance with DIN EN ISO 14477 using a mandrel with a diameter of 10.5 mm. In Figure 3, a plastic film was tested as the blister closure film 1, and in Figure 4, a plastic film containing mineral fillers. In both cases, it can be seen that the test specimen does not tear in the area of ​​maximum applied force (i.e., the measurement curve ends in this area due to the tear and the resulting sudden drop (to zero) in the force required to further advance the test mandrel). Rather, it can be seen that after the maximum force required for further advance of the test mandrel is exceeded, and the resulting elongation of the test specimen, the force required for further advance of the test mandrel decreases until the test specimen tears.This can be explained by the fact that the plastic of the test specimen is stretched in the area of ​​maximum force application, so that the thickness of the test specimen decreases and thus the force required for further stretching of the test specimen also decreases. In contrast to the measurement shown in Fig. 3, for the test specimen with mineral additives (Fig. 4), it can be seen that after exceeding the feed rate at which the maximum force was required, the force required for further feed of the test mandrel does not decrease continuously, but rather, after a rapid drop, decreases comparatively slowly.

[0069] Both a curve such as that shown in Fig. 3 and the curve shown in Fig. 4 are extremely disadvantageous for a film that is to be used as a blister sealing film. This can be explained by the fact that a user does not control the opening of a blister pack by feed control (as the measuring apparatus does), but by force control. A user will therefore continuously increase the force acting on the blister pack until the pack opens. If a user now applies a force that is greater than the maximum force, as shown in the diagrams in Figs. 3 and 4, the further feed will occur very quickly because the force required for the feed decreases. This leads to the blister sealing film tearing open suddenly, under a force that is greater than the force that would actually be necessary to tear open the blister sealing film (AF).This additional or excess force can, for example, be converted into an acceleration of the packaged contents. For example, in blister packs containing tablets with such blister sealing films, it often happens that a tablet is accelerated so quickly after being pressed out that it jumps out of the blister base film and falls to the floor. This renders it unusable and must be disposed of. Blister sealing films with a force / elongation diagram like the one shown in Fig. 3 or 4 are therefore unsuitable for blister packaging of valuable goods.

[0070] Figure 5 shows a comparative representation of the results of a measurement of the puncture resistance of a known metal-containing blister sealing film (A) and a blister sealing film according to the invention (B) measured in accordance with DIN EN ISO 14477 with a mandrel with a diameter of 10.5 mm.

[0071] As can be seen from these diagrams, both blister sealing films A and B do not exhibit the adverse behavior described in connection with Figures 3 and 4. For both blister sealing films, the curve ends immediately after reaching or exceeding the elongation at which the maximum force was required to further advance the test mandrel. This makes it easy for a user to continuously increase the force until the force is reached at which the blister pack opens or the blister sealing film tears.

[0072] Furthermore, Figure 5 shows that the force required to open the blister pack or to tear the blister sealing film is approximately the same. Accordingly, a user can open a blister pack sealed with a blister sealing film as described above with a similar amount of force as with known metal-containing blister sealing films.

[0073] Furthermore, Fig. 5 shows that the stretch required for the blister sealing film to tear is greater. This can be explained by the fact that metal-containing blister sealing films, such as aluminum foil, are only very slightly stretchable and comparatively brittle. This property means that special care must be taken when processing such blister sealing films to avoid damaging the film. A blister sealing film according to the invention can preferably tolerate deformations much better.

[0074] As can be seen from the diagram in Figure 5, the blister sealing film B, the measurement of which is shown, can tolerate, without tearing, deformations (difference in maximum elongation, AL) that are more than twice as large (> 20 units) as the deformation required to tear aluminum foil A (< 10 units). This significantly simplifies the handling of a blister sealing film as described above and allows packaging at very high transport speeds.

[0075] A higher degree of stretching during processing on a blister machine may be advantageous, since the printed blister closure film often has to be stretched when bonding it to a blister base film so that the printed image is adapted to the blister base film.

[0076] During sealing, the sealing tool weakens the plastic slightly, resulting in less elongation than the original plastic (measured under laboratory conditions). The invention counteracts this. Preferably, the blister sealing film can tolerate deformations without tearing that are at least twice as great as those withstandable by, for example, aluminum foil.

[0077] The applicant reserves the right to claim all features disclosed in the application documents as essential to the invention, provided they are novel, individually or in combination, over the prior art. It is further noted that the individual figures also describe features that may be advantageous in and of themselves. The skilled person will immediately recognize that a specific feature described in a figure may be advantageous even without adopting additional features from that figure. Furthermore, the skilled person will recognize that advantages may also arise from a combination of several features shown in individual or different figures.

[0078] List of reference symbols

[0079] 1 blister sealing film

[0080] 2 fleece, fleece layer, second plastic,

[0081] 3 Top layer, plastic layer, first plastic,

[0082] 4 Intermediate layer

[0083] 5 blister base foil

[0084] 10 blister packs,

[0085] A Force-strain curve of a metal-containing blister sealing foil,

[0086] B Force-strain curve of an exemplary blister sealing film according to the invention AF force difference

[0087] AL Difference in maximum strain

Claims

Blister sealing film and blister packaging and process for their production Patent claims Blister closure film (1) comprising a first plastic (3), characterized in that the first plastic (3) is bonded to a nonwoven fabric (2) whose fibers contain a second plastic (2) based predominantly on the same polymers / copolymers as the first plastic (3). Blister closure film (1) according to claim 1, characterized in that the first plastic (3) and the second plastic (2) are based on the same polymers / copolymers to an extent of at least 70 percent by weight, preferably > 80 percent by weight, more preferably > 90 percent by weight, particularly preferably > 95 percent by weight.Blister closure film (1) according to claim 1 or 2, characterized in that the first plastic (3) and the second plastic (2) are selected from a group comprising polyethylene (PE), polypropylene (PP), polystyrene (PS), polyester, including preferably polylactide (PI_A), polyethylene terephthalate (PET) or polycarbonate (PC), ethylene-inyl alcohol copolymer (EVOH) and mixtures thereof. Blister closure film (1) according to one of the preceding claims, characterized in that the thickness of the first plastic (3) and / or the nonwoven fabric (2) is selected such that a puncture resistance of the blister closure film, measured in accordance with DIN EN ISO 14477 with a mandrel with a diameter of 10.5 mm, deviates from a puncture resistance of a 20 μm thick aluminum foil by < 30%, preferably < 20%, and / or is in a range of 15 - 50 N, preferably 20 - 35 N, particularly preferably in the range of 25 - 30 N. Blister closure film (1) according to one of the preceding claims, characterized in that a force acting on the blister closure film (1), preferably in a test of the puncture resistance of the blister closure film based on DIN EN ISO 14477 using a mandrel with a diameter of 10.5 mm, increases continuously until the force necessary for puncture is reached. Blister closure film (1) according to one of the preceding claims, characterized in that it has a sealable layer (2, 4) which, preferably at a sealing temperature in the range of 100 - 170°C, preferably 110 - 160°C, more preferably 120 - 150°C, particularly preferably 130 - 140°C, has a seal seam strength of > 6 N / 15 mm, preferably > 9 N / 15 mm, particularly preferably > 12 N / 15 mm compared to a test specimen comprising the first plastic.Blister closure film (1) according to one of the preceding claims, characterized in that the nonwoven fabric (2) is laminated on at least one side, preferably exactly one side, alternatively on both sides with a layer of the first plastic (3) or is bonded using a hotbonding process. Blister closure film (1) according to one of the preceding claims, characterized in that the nonwoven fabric (2) comprises stretched fibers and / or the first plastic (3) is uni- or bidirectionally stretched. Blister pack (10) comprising a blister base film (5) and a blister closure film (1) according to one of the preceding claims. Blister pack (10) according to claim 9, characterized in that the blister base film (5) and the blister closure film (1) each consist of at least 80 percent by weight, preferably > 90 percent by weight, more preferably > 95 percent by weight, particularly preferably > 98 percent by weight of a plastic. hen, wherein these plastics are based at least to 70 weight percent, preferably > 80 weight percent, more preferably > 90 weight percent, particularly preferably > 95 weight percent on the same polymers / copolymers.

11. A method for producing a blister closure film (1), in particular a blister closure film (1) according to one of claims 1-8, characterized by the steps Providing a fleece (2) which comprises a second plastic, Providing a first plastic (3) which is predominantly based on the same polymers / copolymers as the second plastic, and Connecting the fleece (2) with this first plastic (3).

12. The method according to claim 11, characterized in that the nonwoven fabric (2) is laminated on at least one side, preferably exactly one side, alternatively on both sides with a layer of the first plastic (3) or is connected by a hot bonding process.

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