WO2023030669A1 - Polyolefin blister pack and use thereof - Google Patents

Abstract

The invention relates to a blister pack which is made of a base film and which has one or more depressions produced by thermoforming for receiving the product to be packaged and a cover film connected to the base film. The blister pack is characterized in that the base film and the cover film substantially consist of polyolefin, and at least 50 wt.% of the cover film consists of a cyclic olefin polymer. The blister pack is characterized by an improved recyclability as well as by a high water vapor barrier rating for protecting the packaged product. The blister pack substantially or completely consists of polyolefins and is compatible with sorting and recycling systems for polyolefin waste streams. The blister pack can be advantageously used to package pharmaceutical products.

Description

Description

Polyolefin blister packaging and its use

The present invention relates to blister packs made of plastic, the plastic material of which consists predominantly or entirely of polyolefins and which are particularly easy to recycle.

Press-through packaging, also known as blister packaging, is product packaging that allows the customer to remove the packaged goods individually from the packaging.

Blister packs are used to pack a wide variety of products. For example, pharmaceutical blister packs are often used to package tablets.

The product is presented in front of a cover film or cover film, which is usually printed with information, and fixed with a molded plastic film part, the so-called bottom film. In the case of some push-through packaging, the cover film is made of plastic film, and in the case of pharmaceuticals it is often made of aluminum foil.

Blister packs can be divided into weld packs, clamp packs and staple packs. In the case of welded packaging, the top and bottom foils are connected to one another, which at the same time represents a product seal. With clamp packs, the edges of the bottom foils are bent around the top foil by heating the plastic. In the case of stapled packaging, the top and bottom films are connected to one another using staples.

The bottom foil is shaped using thermoforming technology. Thermoforming or hot forming is a process for forming thermoplastics under the influence of heat and with the help of compressed air, vacuum or stamps. Thermoforming is also known as deep drawing.

Blister packs consist of a thermoformed base film and a cover or lid film that can be partially destroyed by pressing and thus opened so that the goods contained in the pack can be removed.

Current solutions have been developed with a focus on their functionality, i.e. they have a barrier function to protect the content and are easy to open to extract the content, and in some cases are provided with additional properties such as anti-counterfeiting features. In order to meet these individual requirements, current technical solutions typically use and combine different materials, e.g. B. different types of plastics, aluminum, adhesives and prints.

While these material combinations are functional and cost effective, they are also problematic as they combine different plastics and metal foils, making waste sorting and recycling difficult or impossible as the components are inextricably linked. These blisters typically end up in incinerators or landfill. There is therefore a need to develop functional blister packs with improved recyclability.

Typical thermoformed bottom sheet materials used in conventional blister packs are a variety of different polymers, eg, polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polyolefins including cycloolefin polymers, fluoropolymers, ethylene vinyl alcohol copolymers, or combinations thereof. A typical cover foil material used in conventional blister packs is aluminum, with the aluminum foil often being coated with a separate polymeric sealant or adhesive layer for bonding to the bottom foil. Aluminum foil perfectly fulfills the required properties, ie high protective Z-barrier function and easy opening, so that individual products can be taken out by locally breaking the foil. However, blister packs made up of a plastic base film and an aluminum cover film have the disadvantage that they are difficult to recycle or sensibly dispose of, since both components are inextricably linked. Other known solutions are based on plastic or paper. For example, blister packs with PP as the lid and base film are known. This system is easy to recycle, but the deep-drawing process is problematic. The barrier effect is also weaker than with other systems. Paper as a cover film has no barrier effect and is only used in a blister system to protect against dust.

The lid film should have a barrier effect similar to that of the thermoformed, thinned base film in order to prevent the ingress of water vapor or other gases. In addition, it should be made of a similar material to the bottom foil in order to achieve optimal recyclability of the entire blister.

Any adhesive/sealing layer that may be present should also be made from similar raw materials as the base and lid film in order to obtain a mono-material composition for full recyclability.

In addition to aluminum foils, plastics have already been proposed as material for the cover films of blister packs.

Thus, EP 0 838 293 A2 describes monolayer and multilayer films made from one or more cycloolefin copolymers. These are suitable as cover films for blister packs, have a high water vapor barrier and are lightweight push through. Details on the structure of blister packs are not given in this document.

Cover films for blister packs which have at least one layer of cycloolefin polymer or cycloolefin copolymer are known from WO 2009/000403 A1. The cover film is suitable for sealing against all common floor materials, is transparent or translucent and has push-through properties which correspond to a conventional push-through film containing aluminum foil. Various plastics or combinations of plastics are mentioned as materials for the base parts. Specific material combinations of top and bottom films are not disclosed.

While material combinations of conventional blister packs have proven to be functional and cost-effective, they are also problematic, as they usually make waste separation and recycling difficult or impossible. Such blister packs usually end up in incineration or in a landfill.

With tightening legislation in the field of waste disposal and recycling, there is an urgent need for new packaging solutions that have improved recyclability.

Plastic packaging with improved recyclability has already been proposed.

For example, WO 2020/148260 A1 discloses a recycling-friendly push-through packaging. This is not a blister pack, which is typically made up of a deep-drawn base film with a lid film sealed with it, but a combination of two films that are connected to one another over a large area is described, with receiving spaces being formed between these films and with one of the films being weakened in the area of the receiving spaces has, so that these spaces through at this point Can be opened by pressing in order to remove the enclosed product. Both films are mainly made from the same polymer family. Polyethylene, polypropylene or cycloolefin copolymer, for example, are proposed as film materials.

EP 3 808 680 A1 discloses a blister pack made from a thermoformed base film which has at least one layer made from HDPE and a coextruded sealing layer made from HDPE and LLDPE. A three-layer film is used as the cover film, which, in addition to a sealing layer, has a central HDPE layer and an outer HDPE layer. The polyolefin content of the packaging without the packaged goods is preferably more than 90%. Cycloolefin (co)polymers are not mentioned in this document.

As explained above, various partial solutions of polyolefin top or bottom films are known, but no overall system that can be recycled within the meaning of the present requirements.

The present invention provides further thermoformed blister packs with improved recyclability. These are characterized by a high water vapor barrier to protect the packaged goods, consist essentially or entirely of polyolefins and are compatible with sorting and recycling systems for polyolefin waste streams.

The present invention thus offers a mono-material polyolefin push-through blister pack that is fully functional and in which the improved recyclability does not have to be bought at the expense of functional disadvantages, such as in WO002020014826A1, which describes a recyclable film but does not is thermoformable and has disadvantages in the formation of the receiving space for the product to be packaged

In particular, the solution according to the invention provides a barrier blister pack that uses established sorting processes (NIR scanner and metal separators) and recycling processes is compatible with the polyolefin waste streams. In Germany, these waste streams are defined in the minimum standard for assessing the recyclability of packaging that is subject to system participation in accordance with Section 21 (3) VerpackG. The relevant streams are 310 (DE), 324 (DE) and 323 (DE) (PE, PP or MPO (Mixed Polyolefin)). The blister pack is therefore made of a combination of materials that is compatible with these waste streams.

The object of the present invention is therefore to provide a purely polyolefinic blister system with a high moisture barrier, which can be thermoformed on PVC thermoforming systems, meets the recommendations of VDMA Standard Sheet 8747, has good push-through properties, avoids the disadvantage of lacking recyclability and after sorting using NIR and/or eddy current ends up as a mono material in the PE, PP or MPO stream.

Surprisingly, it turned out that cycloolefin polymer-based cover films in combination with a polyolefin base film, in particular with a cycloolefin polymer-containing base film, which are preferably connected to innovative sealing layers, have all the advantages for an excellently recyclable, purely polyolefinic blister system with PVC-types Combine thermoforming properties.

A COC/PE/COC or COC/PP/COC film that is metalized or coated in some other way, for example with AlO _X or SiO _x , offers a comparable barrier to a thermoformed PE/COC/PE or PP even at a thickness of 20 μm /COC/PP bottom film and the entire system is recognized as PE, PP or MPO in recycling sorting (NIR, eddy current). These sorting paths are defined in the German recycling system and bear the designations 310 (DE), 323 (DE), 324 (DE). The blister pack according to the invention consists of material which is fully compatible with the waste stream and which provides valuable material for recycling.

In addition, it was surprisingly found that cycloolefin polymer elastomers or blends thereof and PP copolymers are excellent Are sealing layers between the PE or PP and cycloolefin polymer. This ensures a blister in which the three components base foil, lid foil and adhesive are made from the same raw material base and thus form a fully recyclable mono-material blister.

The present invention relates to blister packs made up of a base film, which has one or more depressions produced by thermoforming for receiving the goods to be packaged, and a cover film connected to the base film. The blister packs according to the invention are characterized in that the base film and the cover film consist essentially of polyolefin and that the cover film consists of at least 50% by weight of cycloolefin polymer.

In the context of the present description, the term "film consisting essentially of polyolefin(s)" means a film which is at least 96% by weight, in particular at least 98% by weight and very particularly preferably at least 99% by weight. -% consists of this material. These can be single-layer films or multi-layer films.

In the context of the present description, “polyolefins” are understood to mean homo- or copolymers derived from ethylenically unsaturated aliphatic and/or cycloaliphatic monomers. In addition to the plastics derived from alpha-olefins, for example from ethylene or propylene, these also include plastics derived from unsaturated bicyclic compounds such as norbornene, for example cycloolefin polymers.

The thickness of the top and bottom films used according to the invention can vary within wide ranges. Bottom foils are usually thicker than top foils. Typical thicknesses for cover films are in the range from 10 μm to 100 μm.

Typical thicknesses for bottom foils are in the range from 50 to 600 μm, preferably in the range from 100 to 600 μm. In the case of multi-layer films, this information relates to the total thickness of the film. The thickness of the foil must be selected so that the contents can be squeezed out, ie the bottom foil must be sufficiently flexible and the lid foil must be flexible enough be sufficiently brittle.

The solution according to the invention offers blister packaging that can be separated into polyolefin waste streams (e.g. PE, PP or MPO (mixed polyolefin)) by conventional sorting processes, such as the use of NIR scanners and downstream separators and separation systems. These sorting paths are, for example, in German recycling system defined and bear the designations 310, 323, 324. The blister pack according to the invention consists of material that is fully compatible with the waste stream and that provides valuable material for recycling.

The blister pack according to the invention preferably has a blister base part and a push-through cover film sealed against the blister base part, the blister base part and cover film consisting of at least 99% by weight of polyolefins.

The blister packs according to the invention are made of materials which are fully compatible with the waste streams in sorting processes sorting into the polyolefin waste streams PE, PP or MPO and moreover provide valuable material for recycling. Such blister packs achieve the rating “green” in the RecyClass rating program.

The cycloolefin polymers used according to the invention are polymers known per se. These can be polymers derived from one monomer or from two or more different monomers.

The cycloolefin polymers are prepared by ring-opening, or especially ring-conserving, polymerization, preferably ring-conserving copolymerization, of cyclic olefins, such as norbornene, with non-cyclic olefins, such as alpha-olefins, especially ethylene.

The choice of catalysts can be controlled in a manner known per se whether the olefinic ring of the cyclic monomer in the Polymerization is preserved or opened. Examples of processes for the ring-opening polymerization of cycloolefins can be found in EP 0 827 975 A2. Examples of catalysts mainly used in ring-preserving polymerization are metallocene catalysts. An overview of possible chemical structures of the polymers derived from cycloolefins can be found, for example, in Pure Appl. Chem., Vol. 77, no. 5, pp. 801-814 (2005).

In the context of this description, the term “cycloolefin polymer” is also to be understood as meaning those polymers which, after the polymerization, have been subjected to hydrogenation in order to reduce any double bonds that are still present.

The cycloolefin polymers used according to the invention in the cover films and base films are thermoplastics which are distinguished by an extraordinarily high transparency.

The glass transition temperature (also referred to below as “T _g ”) of the cycloolefin polymers can be set by those skilled in the art in a manner known per se by selecting the type and amount of the monomers, for example the type and amount of cyclic and non-cyclic monomers. For example, it is known from norbornene-ethylene copolymers that the higher the proportion of norbornene component in the copolymer, the higher the glass transition temperature. The same applies to combinations of other cyclic monomers with non-cyclic monomers.

In the context of the present description, glass transition temperature is to be understood as meaning the temperature determined according to ISO 11357 using the differential scanning calorimetry (DSC) method, the heating rate being 10 K/minute.

Amorphous cycloolefin polymers with glass transition temperatures of more than 30° C. can preferably be used in the cover films and base films of the blister packs according to the invention. The glass transition temperatures are preferably from 40 to 140.degree. C., particularly preferably from 60 to 140.degree.

According to the invention, cycloolefin polymers with glass transition temperatures of 30° C. or below, preferably from 20 to -20° C., can also be used in sealing layers. These are elastomeric cycloolefin polymers, for example the product TOPAS E-140 with a glass transition temperature of 6°C.

worin n 0 oder 1 bedeutet, m für 0 oder eine positive ganze Zahl ist, insbesondere 0 oder 1 , In a further preferred embodiment of the blister pack according to the invention, cycloolefin copolymers (also referred to below as “COC”) are used which are derived from the ring-preserving copolymerization of at least one cycloolefin of the general formula (I) with at least one alpha-olefin of the formula (II).

where n is 0 or 1, m is 0 or a positive integer, in particular 0 or 1,

R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ independently of one another are hydrogen, halogen, alkyl groups, cycloalkyl groups, aryl groups and alkoxy groups, R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ are independently hydrogen and alkyl groups,

worin R²¹ und R²² unabhängig voneinander Wasserstoff und Alkylgruppen bedeuten. R ¹⁷ , R ¹⁸ , R ¹⁹ , R ²⁰ are independently hydrogen, halogen and alkyl groups, where R ¹⁷ and R ¹⁹ can also be bonded to each other such that they form a single ring or a ring system with multiple rings, where the ring or rings may be saturated or unsaturated,

wherein R ²¹ and R ²² are independently hydrogen and alkyl groups.

In a particularly preferred embodiment, cycloolefin copolymers are used which are derived from compounds of the formulas I and II in which n is 0, m is 0 or 1, R ²¹ and R ²² are both hydrogen or R ²¹ is hydrogen and R ²² is one is an alkyl group having one to eight carbon atoms, and R ¹ , R ² , R ⁵ to R ⁸ and R ¹⁵ to R ²⁰ are preferably hydrogen.

In a very particularly preferred embodiment, cycloolefin copolymers are used which are derived from compounds of the formulas I and II, in which the compound of the formula I is norbornene or tetracyclododecene and the compound of the formula II is ethylene.

Very particular preference is given to using copolymers of the type defined above, the copolymerization of which has taken place in the presence of a metallocene catalyst.

Preferred types of cycloolefin copolymers are described in DE 102 42 730 A1. The types Topas®6013, Topas®6015 and Topas®5013 (Topas Advanced Polymers GmbH, Raunheim) can be used with very particular preference as amorphous cycloolefin copolymers.

Mixtures of different cycloolefin polymers can also be used, in particular mixtures of different cycloolefin copolymers.

The preparation of the cycloolefin co- polymers takes place with ring-preserving polymerization, ie the bicyclic or polycyclic structure of the monomer units used are retained during the polymerization. Examples of catalysts are titanocene, zirconocene or hafnocene catalysts, which are generally used in combination with aluminoxanes as co-catalysts. This production method has already been described many times, for example in the patent document mentioned above.

Typical examples of cycloolefin copolymers are copolymers of norbornene or tetracyclododecene with ethylene. Such polymers are commercially available, for example under the trade names APEL® or TOPAS®.

Further examples are cycloolefin polymers derived from ring-opening polymerization of cyclopentadiene or of norbornene. Such polymers are also commercially available, for example under the trade names ARTON®, ZEONEX® or ZEONOR®.

Preference is given to using cycloolefin copolymers which are derived from the above-described monomers of the formulas I and II, these monomers I:II having been used in a molar ratio of 95:5 to 5:95 and which may still have small proportions of structural units, for example bis 10 mol %, based on the total amount of monomers, which are derived from other monomers such as propylene, pentene, hexene, cyclohexene and/or styrene.

Particular preference is given to using cycloolefin copolymers which consist essentially of norbornene and ethylene and which may also contain small proportions, e.g. up to 5% by weight, based on the total amount of monomers, of structural units which are derived from other monomers such as propylene, pentene, hexene , cyclohexene and/or styrene are derived.

The bottom and top films essentially consist of polyolefins, with at least one cycloolefin polymer having to be present in the top film, which accounts for at least 50% by weight of the top film. It can be the cover film be a single-layer film or a multi-layer film. In the case of multilayer films, at least one of the layers consists of at least 50% by weight of cycloolefin polymer.

The single-layer or multi-layer bottom film can contain COC, total COC content preferably >50%, particularly preferably at least 80%.

Films known per se can be used as cycloolefin polymer-based (press-through) cover films used according to the invention, for example films from documents EP 0 838 293 A2, WO 2009/000403 and

WO201 7/140427 A1. It describes single-layer and multi-layer lidding films based on cycloolefin polymers, which have appropriate push-through properties and/or offer protection against tampering, and some of which also have higher barrier properties. The idea of recycling is not mentioned in these documents and is not the focus of them.

The cycloolefin polymer in the top layer ensures that the film is sufficiently brittle and thus has good push-through properties.

Cover films that are preferably used have a water vapor permeability of less than or equal to 0.20 g/m ² /d at 38° C. and a relative humidity of 90%.

The elongation at break of the cover films that are preferably used is greater than 1% and less than 6% (measured according to DIN ENISO 527-1) and thus corresponds to the industry standard VDMA standard sheet 8747.

Preferred cover films are monolayer films containing at least 50% by weight, preferably at least 70% by weight and very particularly preferably at least 90% by weight of cycloolefin polymer or multilayer films containing at least one layer containing at least 50% by weight, preferably at least 70% by weight and very particularly preferably at least 90% by weight cycloolefin polymer, the film having a water vapor permeation of less than or equal to 0.035 g*mm/m ² d at a relative humidity of 85% and a temperature of 23°C, a puncture resistance of less than or equal to 300 N/mm and has a thickness of less than or equal to 100 μm. Cover films of this type are known from EP 838 293 A2.

The bottom foil essentially consists of polyolefin(s). These can be polymers derived from alpha-ethylenically unsaturated aliphatic monomers and/or cycloolefin polymers or mixtures of different polyolefins can be used.

Cycloolefin polymers which are preferably used have been described in detail above.

The bottom film can also be a single-layer or multi-layer film. Multilayer films can be made up of different polyolefins.

The bottom film component of the solution according to the invention can consist of different thermoformed polyolefin films. These films are also known per se. Depending on the required barrier and the processing behavior, a multi-layer composite, such as PP/COC/PP, or a pure polyolefin film, such as PP film, can be used.

The plastic deformability, the shrinkage values (DIN 53377) and the bond strength after deep-drawing (DIN EN ISO 2411) of floor films that are preferably used should correspond to the recommendations of the industry standard VDMA standard sheet 8747.

The polymers derived from alpha-ethylenically unsaturated aliphatic monomers are generally semi-crystalline polymers. These can be polyethylenes, polypropylenes or ethylene-propylene copolymers.

Selected polyethylenes (PE) and/or polypropylenes (PP) are preferably used for the bottom film, or combinations of cycloolefin polymers with selected polyethylenes and/or poly- propylene used or one or more cycloolefin polymers are used.

Preference is given to using one to five-layer base films made from PP, PE, PP/COC/PP, PE/COC/PE, PP/HV/COC/HV/PP, PE/HV/COC/HV/PE or blends of these components and adhesion promoters (HV) consist of this material group

These base films are preferably combined with a one- to three-layer push-through cover film, for example made of COC/PE/COC or COC/PP/COC or blends of these components in the inner and outer layers.

The selected polyethylenes and/or polypropylenes can be semi-crystalline ethylene homopolymers, which preferably have a crystallite melting point of 130 to 140° C., semi-crystalline ethylene-Cs-Cs-alpha-olefin copolymers, which preferably have a crystallite melting point of 50 up to 130 °C, to have partially crystalline propylene homopolymers, which preferably have a crystallite melting point of 160 to 165 °C and/or to partially crystalline propylene-C4-C8-alpha-olefin copolymers, which preferably have a crystallite melting point of 100 up to 160°C.

In the context of the present description, crystallite melting temperature is understood to mean the temperature determined according to ISO 11357 using the differential scanning calorimetry (DSC) method, the heating rate being 10 K/minute.

Examples of Cs-Cs-alpha-olefins are propylene, butene-1, hexene-1, octene-1. Homo- or copolymers based on ethylene or propylene can be used.

The polyolefins used for the bottom film are linear or branched types. The sequence of different monomer units in these polyolefins may be random or in the form of blocks. The individual monomer units can be sterically differently arranged, for example isotactically, syndiotactically or atactically.

Preferred polyolefins are polyolefin homopolymers derived from ethylene or propylene or polyolefin copolymers derived from ethylene and/or propylene with a proportion of up to 10% by weight of higher alpha-olefins having 4-8 carbon atoms. In this context, copolymers are also to be understood as meaning polymers which are derived from three or more different monomers.

Polyethylenes used with very particular preference are high-density (HDPE), medium-density (MDPE) and low-density (LDPE) polyethylene. These polyethylenes are manufactured using the low or high pressure process with appropriate catalysts and are characterized by their low density compared to other plastics (<0.96 g/cm ³ ), their high toughness and elongation at break, and their very good electrical and dielectric properties very good chemical resistance and, depending on the type, high resistance to stress cracking and good workability and machinability.

The polyethylene molecules contain branches. The degree of branching of the molecular chains and the length of the side chains have a significant influence on the properties of the polyethylene. The HDPE and MDPE types are less branched and only have short side chains.

Polyethylene crystallizes from the melt as it cools. The long molecular chains arrange themselves folded in some areas and form very small crystallites, which are combined with amorphous zones to form superstructures, the so-called spherulites. Crystallization is all the more possible the shorter the chains are and the lower the degree of branching. The crystalline portion has a higher density than the amorphous portion. Different densities are therefore obtained, depending on the crystalline content. Depending on the type of polyethylene, this degree of crystallization is between 35% and 80%. In the case of high-density polyethylene (HDPE), a degree of crystallization of 60% to 80% is achieved at densities between 0.940 g/cm ³ and 0.97 g/cm ³ . In the case of medium-density polyethylene (MDPE), a degree of crystallization of 50% to 60% is achieved at a density of 0.930 g/cm ₃ to 0.940 g/cm ³ . In the case of low-density polyethylene (LDPE), a degree of crystallization of 40% to 50% is achieved at densities between 0.915 g/cm ³ and 0.935 g/cm ³ . This type involves highly branched polymer chains, which result in low density.

Linear low-density polyethylene (LLDPE) is also known. Its polymer molecule has only short branches. These branches are produced by the copolymerization of ethylene and higher alpha-olefins such as butene, hexene or octene. The degree of crystallization of this type is 10 to 50% and the density ranges from 0.87 g/cm ³ to 0.940 g/cm ³ .

The properties of polyethylene are primarily determined by density, molecular weight and molecular weight distribution. So e.g. B. the impact and notched impact strength, tear strength, elongation at break and resistance to stress cracking with the molecular weight. Narrowly distributed HDPE with a low low molecular weight content is more impact resistant, even at low temperatures, than broadly distributed HDPE within the same ranges for melt index and viscosity number. Broadly distributed types, on the other hand, are easier to process.

Polypropylene is an isotactic, syndiotactic or atactic polypropylene produced with the help of stereospecifically acting catalysts. The isotactic polypropylene in which all the methyl groups are arranged on one side of the imaginary zigzag molecular chain is particularly preferably used in the base films of the blister packs according to the invention.

On cooling from the melt, the regular structure of the isotactic polypropylene favors the formation of crystalline areas. However, the chain molecules are rarely built into a crystallite in their full length, since they also contain non-isotactic and therefore non-crystallizable components. In addition, amorphous areas arise due to the entanglement of the chains in the melt, especially with a high degree of polymerization. The crystalline content depends on the manufacturing conditions of the molded parts and is 50% to 70%. Due to the high secondary forces in the crystallite, the partially crystalline structure causes some strength and rigidity; while the disordered regions with the higher mobility of their chains provide flexibility and toughness to segments above the glass transition temperature.

The density of polypropylene is very low, between 0.895 g/cm ³ and 0.92 g/cm ³ . Polypropylene moldings are characterized by higher rigidity, hardness and strength compared to polyethylene moldings. Polypropylene has a glass transition temperature of 0 to -10 °C. The crystallite melting range is 160 to 165 °C. These temperatures can be modified by copolymerization; the measures for this are known to the person skilled in the art.

Polyolefins preferably used are HDPE, MDPE, LDPE, LLDPE, HMWPE, UHMWPE, propylene homopolymers, propylene copolymers with 1-10% by weight of structural units derived from 1-alkenes with 4-8 carbon atoms, propylene-ethylene copolymers with 10 to 90% by weight % of structural units derived from propylene, and combinations of two or more thereof.

The combination of different polyolefins usually results in incompatible polymer mixtures. This means the formation of heterogeneous systems. The compositions according to the invention are therefore generally cloudy.

For example, cycloolefin polymers have high transparency and low haze values. Blends of cycloolefin polymers and other polyolefins will be less transparent due to the multiphase nature of these blends. In the mixtures, different components will form discrete phases of the individual materials. This property leads to reduced transparency of mixtures of these components. In a particularly preferred embodiment, the base films used according to the invention use polyolefins whose refractive indices differ little or not at all. These compositions have a significantly higher transparency than compositions made from polyolefins with significantly different refractive indices.

The bottom film can be a single-layer film or a multi-layer film.

Preferred base films are monolayer films consisting of 96% by weight, preferably at least 98% by weight and very particularly preferably at least 99% by weight of polyethylene, polypropylene, cycloolefin polymer or mixtures of two or more of these polyolefins or multilayer films consisting of at least 96% by weight %, preferably at least 98% by weight, or and most preferably at least 99% by weight, consist of polyolefins, the polymers in the individual layers consisting of polyethylene, polypropylene, cycloolefin polymer or mixtures of two or more of these polyolefins.

In addition to the polyolefin(s) that must be present, the top and/or bottom film can also contain additives that are customary per se. The total proportion of these additives is usually up to 4% by weight, based on the mixture as a whole, preferably up to 1% by weight.

Additives, also known as auxiliaries or additives, are substances that are added to the polyolefin in small amounts in order to achieve or improve certain properties, for example to achieve a positive effect on production, storage, processing or product properties during and after the use phase.

The additives can be processing aids, such as oils or waxes, or additives which are of the invention give a specific function to the polyolefin film used, such as plasticizers, UV stabilizers, matting agents, preservatives, biocides, antioxidants, antistatic agents, flame retardants, reinforcing agents, fillers, pigments or dyes.

Films of cycloolefin polymer which are not stretched after production or which have been stretched one or more times can be used as cover films.

Polyolefin films, preferably cycloolefin polymer films, which have usually been thermoformed after production, can be used as bottom films.

The top film can be connected to the thermoformed bottom film, which already contains the goods to be packaged, without further pre-treatment. The top and bottom films can be connected by gluing, in particular by heat sealing, clamping or stapling. The connection is preferably made by gluing. These procedures are known to those skilled in the art.

The monolayer and multilayer films from EP 0 838 293 A2 are preferably used as cover films.

The cover film is preferably also provided with one or more barrier layers and/or adhesive layers before it is connected to the bottom film.

Thin metal or metal oxide layers or SiO _x coatings are particularly suitable as barrier layers. These are usually applied to the cover film by vapor deposition or sputtering. These barrier layers are known to those skilled in the art. The thickness of these layers ranges from 1 nm to 1 pm, in particular from 3 nm to 100 nm.

A connecting layer can be applied between the two films to connect the top and bottom films. This can be formed by an adhesive which has been applied to the top and/or bottom foil before the foils are joined, or this is presented in the form of a foil between the top and bottom foil. Hot-melt adhesives, adhesive adhesives or chemically curing adhesives are suitable as adhesives. Hot melt adhesives are preferably used. These are presented in particular in the form of a film between the top film and the bottom film. Various polyolefins are suitable as hot-melt adhesives. Their melting point is below the melting point of the material of the cover and base film.

Preferred connecting layers, also called adhesion promoter or sealing layers, can consist of PP plastomer, COC elastomers or blends of these components.

A cycloolefin polymer is preferably used as the hot-melt adhesive, in particular an elastomeric cycloolefin polymer, for example the product Topas® E140 from Topas Advanced Polymers GmbH, Frankfurt am Main.

Preferred blister packs have cover films which have a barrier layer, in particular barrier layers consisting of a vapor-deposited metal layer or metal oxide layer or a silicate layer.

Further preferred blister packs are characterized in that the base film essentially consists of polyethylene, polyethylene-polypropylene copolymers, polypropylene, cycloolefin polymer or mixtures of two or more of these polymers.

Preferred blister packs are those in which the proportion by weight of polyolefin in the cover film and in the base film is at least 99% in each case.

Particularly preferred blister packs are characterized in that the cycloolefin polymer is a cycloolefin copolymer, in particular a cycloolefin copolymer consisting of structural units derived from ethylene and norbornene. Further particularly preferred blister packs are characterized in that the cyclic olefin polymer has a glass transition temperature between 60 and 140°C, preferably between 75 and 115°C

In a preferred variant of the blister packs according to the invention, the bottom film is a single-layer film containing 5 to 30% by weight of cyclic olefin polymer and 95 to 70% of polyethylene and/or polypropylene.

In a further preferred variant of the blister packs according to the invention, the base film is a multilayer film of which at least one layer consists of at least 90% by weight, preferably at least 95% by weight and very particularly preferably at least 99% by weight of cycloolefin polymer and the rest Layers consist of at least 90% by weight, preferably at least 95% by weight and very particularly preferably at least 99% by weight, of polyethylene, polypropylene, polyethylene-polypropylene copolymers.

Further preferred blister packs according to the invention are characterized in that they have a sealing layer between the top and bottom films, the material of which consists of at least 90% by weight, preferably at least 95% by weight and very particularly preferably at least 99% by weight of polyolefin at least 90 wt.%, preferably at least 95 wt.% and most preferably at least 99 wt.% of cycloolefin polymer and most preferably at least 90 wt.%, preferably at least 95 wt.% and most preferably at least 99% by weight of elastomeric cycloolefin copolymer.

The blister packs according to the invention are suitable for packaging goods of all kinds. Solids are preferably packaged. However, it can also be liquids or gels.

The blister packs according to the invention preferably contain pharmaceutical ceutic products such as bandages, sterile instruments or, in particular, pharmaceuticals, preferably in solid form, such as in the form of tablets, capsules or suppositories.

Preferred blister packs contain an illustration of a withdrawal plan for the pharmaceutical products on the pack.

The invention preferably relates to the use of the blister packs described above for packaging medicaments.

The examples below illustrate the invention without limiting it.

The blister systems examined were classified using the RecyClass assessment tool (https://recvclass.eu/de/recyclass-online-tool/). The overall grade “green” was always achieved for the blister systems according to the invention described below, while the prior art blister systems described below are either not recyclable (grade “red”) or receive the grade “green”, but only cover the low barrier range.

Comparative Examples C1 to C3

These are thermoformed bottom sheets sealed with 20 μm thick aluminum foil.

Example VI : Floor foil made of PVC / PE / PVDC (90g)

Example V2: bottom foil made of PP 250 μm

Example V3: bottom foil made of PP 30 pm / COC 240 pm / PP 30 pm

All of these blister systems are unsuitable for evaluating the recycling behavior due to the aluminum foil layer thickness of > 5 μm. Modern eddy current sorters operated by recyclers capture all thick ones aluminum parts and separate them into the aluminum fraction. Therefore, plastic packaging with a thick layer of aluminum enters the aluminum recycling stream and the plastics are lost.

Examples 1 and 2 according to the invention

These are innovative barrier blister systems with a barrier-coated polyolefin cover film instead of aluminum and with fully recyclable sealing layers.

Example 1 :

Bottom film: PP 30 pm / HV 10 pm / COC 240 pm / HV 10 pm / PP 30 pm sealed with cover film 20 pm COC / PP + HV + COC / COC AlOx or SiOx HV = PP elastomer blend

Note: Variant PP 30 pm / HV 10 pm / COC 240 pm possible, provided that the materials are barrier and recyclable

RecyClass classification "green

CLASS A if size of sorted blister > 50 x 50 mm

CLASS B if the size of the sorted blister is between 20 x 20 and 50 x 50 mm

Example 2:

Bottom foil: PE 30 pm / HV 10 pm / COC 240 pm / HV 10 pm / PE 30 pm sealed with cover foil 20 pm COC / PE / COC AlOx or SiOx

HV = COC elastomer

Note: Variant PE 30 pm / HV 10 pm / COC 240 pm possible, provided the materials are barrier-free and recyclable

RecyClass classification "green"

CLASS A if size of sorted blister > 50 x 50 mm

CLASS B if the size of the sorted blister is between 20 x 20 and 50 x 50 mm

The films in the blister packs of Examples 1 and 1 according to the invention 2 consist of at least 99% polyolefins and thus combine excellent recycling behavior with a high water vapor barrier, good sealing behavior, good push-through properties and the bottom films can be thermoformed on standard PVC thermoforming systems in accordance with the specifications of VDMA Standard Sheet 8747.

Claims

26 patent claims 1 . Blister packs made up of a base film, which has one or more depressions produced by thermoforming for receiving the goods to be packaged, and a cover film connected to the base film, characterized in that the base film and the cover film consist essentially of polyolefin and that the cover film consists at least 50% by weight of cycloolefin polymer. 2. Blister packs according to claim 1, characterized in that the cover film has a barrier layer. 3. Blister packs according to at least one of claims 1 to 2, characterized in that the barrier layer consists of a vapor-deposited metal layer or metal oxide layer or of a silicate layer. 4. Blister packs according to at least one of claims 1 to 3, characterized in that the bottom film consists essentially of polyethylene, polyethylene-polypropylene copolymers, polypropylene, cycloolefin polymer or mixtures of two or more of these polymers. 5. Blister packs according to at least one of claims 1 to 4, characterized in that a single-layer film or a multi-layer film is used as the bottom film. 6. Blister packs according to at least one of claims 1 to 5, characterized in that the proportion by weight of polyolefin in the top film and in the bottom film is at least 99%. 7. Blister packs according to at least one of claims 1 to 6, characterized in that the cycloolefin polymer is a cycloolefin copolymer. 8. Blister packs according to at least one of Claims 1 to 7, characterized in that the cycloolefin polymer is an amorphous cycloolefin polymer which has a glass transition temperature between 60 and 140°C, and in particular between 75 and 115°C. 9. Blister packs according to at least one of claims 1 to 8, characterized in that the cyclic olefin polymer is a cycloolefin copolymer consisting of structural units derived from ethylene and norbornene. 10. Blister packs according to at least one of claims 1 to 9, characterized in that the bottom film is a single-layer film containing 5 to 30% by weight cycloolefin polymer and 95 to 70% polyethylene and/or polypropylene, or that the bottom film is a multi-layer film , at least one layer of which consists essentially of cycloolefin polymer and the remaining layers consist essentially of polyethylene, polypropylene, polyethylene-polypropylene copolymers. 11 . Blister packs according to at least one of Claims 1 to 10, characterized in that the cover film has a puncture resistance of less than or equal to 300 N/mm. 12. Blister packs according to at least one of claims 1 to 11, characterized in that they consist entirely of materials that ensure compatibility with a PE, PP or MPO recycling stream. 13. Blister packs according to at least one of claims 1 to 12, characterized in that the cover film has a water vapor permeation of less than or equal to 0.2 g/m ² /d at a relative humidity of 90% and a temperature of 38°C. 14. Blister packs according to at least one of claims 1 to 13, characterized in that these between a top and bottom film Has sealing layer whose material consists essentially of polyolefin. 15. Blister packs according to claims 1 to 14, characterized in that the material of the sealing layer essentially consists of cycloolefin polymer. 16. Blister packs according to claims 1 to 15, characterized in that the material of the sealing layer essentially consists of elastomeric cycloolefin copolymer. 17. Blister packs according to at least one of claims 1 to 16, characterized in that they meet the specifications and requirements of Directive 2018/852 of the European Parliament and the German Packaging Act (VerpackG). 18. Use of a blister pack according to at least one of claims 1 to 17 for packaging pharmaceutical products. 19. Use according to claim 18, characterized in that the pharmaceutical product is a bandage, a sterile instrument or a drug. 20. Use according to claim 19, characterized in that the pharmaceutical product is a drug.