Polymeric sheet and blister pack comprising said polymeric sheet, method for manufacturing said blister pack

Abstract

A polymeric sheet (4) comprises a polymer of the polyethylene family characterized by an elongation at break in the transverse direction less than or equal to 15% and by a tensile strength at break in the transverse direction less than or equal to 37 MPa. A press-through blister pack (1) for the pharmaceutical, nutraceutical, cosmetic, or food sector comprises an upper wall (12) and a breakable wall (14) mutually constrained so as to form and tightly seal one or more containment chambers (3) for drugs or supplements. The upper wall (12) and the breakable wall (14) are both made of polymeric material, and the breakable wall (14) comprises a polymeric sheet (4) according to the present invention. A method for manufacturing a blister pack (1) according to the present invention.

Description

"POLYMERIC SHEET AND BLISTER PACK COMPRISING SAIDPOLYMERIC SHEET , METHOD FOR MANUFACTURING SAID BLISTER PACK" DESCRIPTIONField of application

[0001] The present invention relates to a polymeric sheet , a press-through blister pack for the pharmaceutical , nutraceutical , cosmetic, or food sector for containing pharmaceutical or nutraceutical or cosmetic products or foodstuf fs such as drugs , supplements or the like , for example in the form of tablets , powders , liquids , hard or soft capsules , comprising a polymeric sheet according to the present invention, and finally to a method for manufacturing such a blister pack .

[0002] In the field of blister packs for pharmaceuticals and nutraceuticals , in particular for press-through blister packs , the use of polymeric materials is known for the manufacture of the rigid portion of the blister pack, also known as the top, i . e . , the part in which the seats for the aforementioned drugs or supplements or the remaining elements are obtained, generally by thermoforming .

[0003] The closing sealing sheet , also known as the lid, i . e . the portion of blister pack material that is broken under pressure in order to access the contents of saidblister pack, is currently made mainly of aluminum, due to good features of strength and the intrinsic fragility of the material , which makes the product extremely easy to open . These portions are generally welded together by heat-seal resins , generally belonging to classes of materials that are di f ferent from both those used for the top and those used for the lid .

[0004] Disadvantageously, this classic solution is no longer up to date with current sustainability requirements . In fact , blister packs made of such materials are to date hardly manageable with regard to di f ferentiability, since the separation of the rigid part from the sealing sheet is extremely complicated, especially at sealing points .

[0005] Therefore , these solutions have to date a high environmental impact and do not meet the increasingly stringent demand for ecological solutions .

[0006] Alternative blister pack solutions that satis fy the recyclability requirement are also being studied and developed; for example , polymeric mono-material blister packs have been proposed on the market .

[0007] Some recently promoted solutions provide for blister packs made entirely of polypropylene ( PP ) or polyethylene terephthalate ( PET ) .

[0008] Disadvantageously, these solutions have drawbackslinked to the poor mechanical properties of the material for this type of application . For example , such blister packs were found to be di f ficult to open, due to the poor breakability of the sealing sheet . According to a further disadvantage , such solutions of fer insuf ficient impermeability to the passage of oxygen, which compromises the contents of said blister pack .

[0009] In order to overcome these drawbacks , some known solutions provide for incisions or pre-cuts made in the sealing sheet to facilitate the opening thereof .

[0010] Disadvantageously, it is immediately understood that these solutions are of poor quality since they expose the pharmaceutical and nutraceutical products contained in the blister pack to any external contamination, as well as the passage of oxygen and humidity, negatively af fecting the premature degradation of the product and / or its beneficial ef fects .Solution of the invention

[0011] There appears to be a signi ficant need therefore to provide a polymeric sheet , a press-through blister pack, and the manufacturing method thereof that is capable of overcoming the drawbacks typical of the prior art .

[0012] There is also a need to limit the use of multimaterial blister packs which are di f ficult to di f ferentiate and therefore have a non-negligibleenvironmental impact .

[0013] In particular, the obj ect of the present invention is to provide a polymeric sheet that may be applied for the breakable wall in pharmaceutical blister packs to make them more sustainable from an environmental impact point of view, while maintaining excellent properties of oxygen impermeability, mechanical resistance , and ease of opening .

[0014] This requirement is satis fied by a polymeric sheet and a press-through blister pack according to the accompanying independent claims . The claims dependent thereupon describe preferred or advantageous embodiments of the invention, comprising further advantageous features .Description of the drawings

[0015] The features and advantages of the polymeric sheet , the press-through blister pack, and the manufacturing method will become apparent from the description provided hereinafter of some preferred embodiments , given by way of indicative and non-limiting example , with reference to the accompanying figures , wherein :Fig . 1 is a schematic view of a press-through blister pack according to the present invention;Fig . 2 is a schematic view of a polymeric sheet in one embodiment of the invention;Fig . 3 is a schematic view of a polymeric layer as sembly according to one embodiment of the invention;Fig . 4 is a schematic view of a press-through blister pack according to one embodiment of the present invention;Fig . 5 is a table listing the properties of a high- density polyethylene used for the manufacture of a press- through blister pack in one embodiment of the present invention;Fig . 6 is a table listing the properties of a 1-octene ethylene copolymer used for the manufacture of a press- through blister pack in one embodiment of the present invention;Fig . 7 is a table listing the properties of an ethylenehexene copolymer used for the manufacture of a press- through blister pack in one embodiment of the present invention;Fig . 8 is a table listing the properties of a high- density polyethylene used for the manufacture of a press- through blister pack in one embodiment of the present invention;Fig . 9 is a table representing an exemplary embodiment of an upper wall and a breakable wall of a press- through blister pack in one embodiment of the present invention .Detailed description

[0016] With reference to the aforesaid figures , a blister pack 1 for the pharmaceutical , nutraceutical , cosmetic, or food sectors has been indicated as a whole with the reference numeral 1 .

[0017] The blister pack 1 is preferably a press- through blister pack .

[0018] Referring to Fig . 1 or 4 , the blister pack 1 comprises an upper wall 12 and a breakable wall 14 mutually constrained so as to form and tightly seal one or more containment chambers 3 suitable for housing pharmaceutical or nutraceutical or cosmetic or food products , for example in the form of tablets , powders , liquids or hard or soft capsules .

[0019] Preferably, the upper wall 12 and the breakable wall 14 are at least partially welded together, even more preferably heat-sealed .

[0020] Preferably, the upper wall 12 and the breakable wall 14 are welded together along the entire surface surrounding such one or more chambers 3 , i . e . , along the wall surface not facing said one or more chambers 3 .

[0021] In one embodiment , the breakable wall 14 comprises a polymeric sheet 4 .

[0022] In one embodiment , the breakable wall 14 is composed of said polymeric sheet 4 .

[0023] Preferably, the breakable wall 14 is composedexclusively of such polymeric sheet 4 .

[0024] In a preferred embodiment , the upper wall 12 and the breakable wall 14 are both made of polymeric material , preferably of the same polymeric material or of di f ferent materials but belonging to the same family of polymers .

[0025] It is clear that it is intended that the walls are predominantly made of polymeric material unless there are additives and inorganic fillers and impurities in the material . Preferably each wall is made of at least 95% polymeric material .

[0026] Preferably, both the upper wall 12 and the breakable wall 14 are made of materials belonging to the polyolefin family, even more preferably belonging to the polyethylene ( PE ) family .

[0027] The polymeric sheet 4 identi fies in space an imaginary plane of predominant extension and in particular a longitudinal direction and a transverse direction of predominant extension in which the polymeric sheet predominantly extends .

[0028] Furthermore , the polymeric sheet 4 is small in thickness , i . e . , it extends much less , in a direction orthogonal to said plane .

[0029] According to the present invention, the polymeric sheet 4 comprises a polymer of the polyethylene family, preferably a copolymer comprising at least one ethylenegroup, even more preferably a 1-octene ethylene and / or high-density polyethylene (HDPE ) copolymer, characteri zed by an elongation at break in the transverse direction less than or equal to 15% , where elongation at break in the transverse direction is calculated by the method according to the ASTM D882 standard .

[0030] In a preferred embodiment , the polymer has an elongation at break in the transverse direction equal to 3% .

[0031] According to the invention, the polymer is characteri zed by a tensile strength at break in the transverse direction of less than 40 MPa .

[0032] In one embodiment the polymer is a high-density polyethylene characteri zed by a tensile strength at break in the transverse direction equal to 37 MPa .

[0033] In one embodiment the polymer is a 1-octene ethylene copolymer characteri zed by a tensile strength at break in the transverse direction equal to 19 MPa .

[0034] In one embodiment , the polymer of the aforementioned polyethylene family is characteri zed by an elongation at break in the longitudinal direction of less than or equal to 500% , where the elongation at break is calculated by the method according to the ASTM D882 standard .

[0035] Preferably, the polymeric sheet comprises a 1-octene ethylene copolymer with a density between 0 . 940 and0.965 g / cm3, preferably 0.961 g / cm3, calculated according to the ASTM D792 standard.

[0036] In a preferred embodiment, the polymeric sheet comprises a high-density polyethylene characterized by a density between 0.940 and 0.965 g / cm3, preferably equal to 0.961 g / cm3.

[0037] Surprisingly, the Applicant, during a step of evaluating polymers and copolymers in terms of longitudinal elongation at break to evaluate the orientation and stretching faculties thereof, has found in an unexpected manner that some particular types of polyethylenes (specific 1-octene ethylene copolymers or specific HDPEs) have transverse elongation values at break, generally not considered for the evaluation of these polymers for film application, which are extremely low (indeed, less than or equal to 15%) compared to the average of polymers and copolymers of the same family (which are around 500 to 700%) .

[0038] From this evaluation, the Applicant has verified and tested the application, never previously considered in this sector, of such a material to make breakable walls of blister packs and has verified that the use of such a material confers surprisingly advantageous properties to said blister pack.

[0039] In one embodiment, the polymeric sheet 4 ismultilayer .

[0040] In the present discussion, the strati fication of the polymeric sheet is carried out along the orthogonal direction, i . e . , all the layers have a planar extension predominantly in the longitudinal and transverse directions and are superimposed on each other along the direction orthogonal thereto .

[0041] In one embodiment , the polymeric sheet 4 is monooriented .

[0042] In the present discuss ion, the term "mono-oriented" refers to a layer that has undergone a stretching process in one direction only (mono-orientation) . In other words , the mono-oriented polymeric sheet has polymer chains oriented predominantly along a preferred direction — also referred to as the machine direction . Preferably, the mono-orientation is applied to the sheet in the longitudinal direction ( i . e . , in one of the directions of greatest extension of the polymeric sheet , preferably a direction tangent to the imaginary plane identi fied by the polymeric sheet 4 .

[0043] Preferably, the mono-orientation is applied when the polymeric sheet 4 comprises a polymer / copolymer having an elongation at break in the high longitudinal direction ( i . e . , at least greater than 100% ) . In this situation, in fact , the mono-orientation is applied along thelongitudinal direction, precisely with the aim of reducing the residual elongation at break of the material in such direction ( i . e . , weakening it also in the longitudinal direction) . This operation makes it possible to further facilitate the opening of the blister pack, af fecting the breaking load of the entire polymeric sheet 4 .

[0044] The stretching process will be better described later in the present discussion .

[0045] In one embodiment , the polymeric sheet 4 comprises a polymer having an elongation at break in the longitudinal direction comparable to the elongation at break in the transverse ( low) direction .

[0046] Where the polymeric sheet 4 comprises a polymer / copolymer characteri zed by an elongation at break in the low longitudinal direction, comparable to that in the transverse direction, the mono-orientation process in the longitudinal direction may be avoided .

[0047] In one embodiment , the polymeric sheet 4 is filled with one or more additives that reduce the permeability to oxygen and humidity .

[0048] Preferably, said one or more additives are selected from the group comprising : clay crystallites , talc, graphene or other inorganic compounds having a lamellar structure . In an advantageous embodiment , the polymericsheet is filled with talc particles.

[0049] In one embodiment, the polymeric sheet 4 is admixed with a mineral filler.

[0050] The term "mineral filler" refers to one or more preferably inorganic additives.

[0051] Preferably, the mineral filler is dispersed in a concentration between 10% and 50% (w / w) with respect to the total mass of the polymeric sheet 4, even more preferably between 30% and 50% (w / w) .

[0052] In one embodiment, the mineral filler is selected from the group comprising calcium carbonate, talc, zeolites, kaolin, silica, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, aluminum hydroxide, magnesium hydroxide, zinc oxide, alumina, mica.

[0053] In a preferred embodiment, the mineral filler is only calcium carbonate.

[0054] Advantageously, calcium carbonate, due to a low hygroscopicity, allows particle sizes to be obtained that are smaller than those obtainable with other fillers.

[0055] In one embodiment, the mineral filler also comprises talc .

[0056] In one embodiment, the breakable wall 14 has a thickness of less than or equal to 60 microns, more preferably less than or equal to 25 microns, even morepreferably equal to 25 microns.

[0057] In a preferred embodiment, the mineral filler has a particle size between 1 and 5 microns, more preferably between 1.5 and 2.5 microns, even more preferably 1.7 microns, preferably measured according to the ISO13317 standard .

[0058] In one embodiment, the upper wall 12 comprises a polymeric layer assembly 2, preferably coextruded.

[0059] In one embodiment, the polymeric layer assembly 2 comprises HDPE (high-density polyethylene) and VLDPE (very low-density polyethylene) .

[0060] In one embodiment, the upper wall 12 has a thickness between 300 microns and 400 microns, endpoints included.

[0061] Preferably, the polymeric layer assembly 2 comprises HDPE (high-density polyethylene) and VLDPE (very low- density polyethylene) with a thickness ratio of HDPE and VLDPE between 1.5 and 19, endpoints included.

[0062] That is, the ratio of the thickness of the HDPE layer to the VLDPE layer coextruded to form the polymeric layer assembly 2 is between 1.5 and 1.9, endpoints included .

[0063] In other words, the proportion HDPE: VLDPE is between 60:40 and 95:5.

[0064] Preferably, with reference to Fig. 3, the polymeric layer assembly 2 is a film comprising two layers 20, 21of HDPE (high-density polyethylene ) and a sealing layer22 of ethylene-hexene copolymer .

[0065] In a preferred embodiment , the polymeric layer assembly 2 constitutes an asymmetrical film comprising the layers in order :- HDPE layer 20- HDPE layer 21- sealing layer 22 .

[0066] The outermost layer of HDPE 20 is suitable for acting as a barrier layer .

[0067] Preferably, the HDPE layers 20 , 21 are characteri zed by a density between 0 . 952 and 0 . 962 g / cm3 (ASTM D1505 ) , endpoints included .

[0068] Preferably, the ethylene-hexene copolymer is a resin that acts as a sealing layer 22 , i . e . , it is suitable for being heated in order to heat-seal the upper wall 12 and the breakable wall 14 therebetween .

[0069] That is , the ethylene-hexene copolymer layer 22 is suitable for facing the breakable wall 14 to allow heatsealing to the upper wall 12 in the blister pack assembly condition .

[0070] Preferably, the multilayer polymeric sheet 4 comprises a sealing layer 42 . Preferably, the sealing layer of the polymeric sheet has a thickness of 10% with respect to the total thickness of the polymeric sheet 4 .

[0071] Preferably, such sealing layer 42 is coextruded with1-octene ethylene copolymer or with HDPE to form the polymeric sheet 4.

[0072] Even more preferably, the sealing layer 42 of the polymeric sheet 4 is also made of ethylene-hexene copolymer and is suitable to act as a sealing agent with the upper wall 12.

[0073] That is, the breakable wall 14 has the sealing layer on the side facing the upper wall 12 to allow heatsealing to the upper wall 12.

[0074] Preferably, the sealing layer 22, 42 (in the polymeric sheet 4 or in the layer assembly 2) is made of a plastomeric resin, preferably of an ethylene-hexene copolymer having a density less than 0.910 g / cm3 (ASTM D792) , even more preferably equal to 0.908 g / cm3, a melt index (190°C / 2.16 kg) between 2 and 4 g / 10 min (ASTM D1238) and a peak melting temperature less than or equal to 114°C, preferably measured by differential scanning calorimetry (DSC) , preferably measured according to the ISO11357 standard.

[0075] Preferably, this ethylene-hexene copolymer has a Vicat softening temperature of 90°C, calculated according to the ASTM D1525 standard.

[0076] In one embodiment, the multilayer sheet 4 comprises additives suitable for decreasing the permeability tooxygen . Such additives are also known as gas-stop particles .

[0077] The mono-oriented polymeric sheet 4 according to one embodiment of the invention is obtained by means of a stretching process in the longitudinal direction of the polymeric sheet . This stretching, applied only along one direction ( the longitudinal direction) , causes an elongation of the polymeric sheet and a further decrease in the elongation at break in the transverse direction thereof , further facilitating the breakabi lity thereof .

[0078] Said elongation is preferably implemented by means of the passage of the polymeric sheet through a stretching machine compris ing a series of cylinders that rotate at progressively increasing tangential speeds . Said cylinders are thermally controlled so as to allow the material that makes up the polymeric sheet to reach the softening temperature thereof , so as to be easily elongated but without excessive plasticity in order to allow the formation of microfractures in the vicinity of the mineral filler particles .

[0079] The stretching ratio typically applied, where " stretching ratio" means the ratio between the final speed of the cylinders and the initial speed before the stretching machine , is between 2 and 4 .

[0080] In the embodiment wherein the polymeric sheet 4 alsocomprises the sealing layer 42 , the 1-octene ethylene copolymer or the HDPE and the ethylene-hexene copolymer are coextruded to form the polymeric sheet 4 .

[0081] The polymeric sheet 4 is preferably made by means of filming, either cast or blown .

[0082] It is clear that the present invention relates per se to a polymeric sheet 4 for a breakable wall 14 of a press-through blister pack 1 according to any of the embodiments described in the present discussion .

[0083] In one exemplary application, a press-through blister pack 1 according to one embodiment of the invention is made with an upper wall 12 and a breakable wall 14 comprising commercial materials as shown in the table of Fig . 9 .

[0084] In one exemplary application, the upper wall 12 is a coextruded film comprising two layers 20 , 21 of high- density polyethylene having the properties listed in the table shown in Fig . 8 ( e . g . , according to the speci fic exemplary application of the table in Fig . 9 , such high- density polyethylene is HDPE HTA002 from ExxonMobilTM) and a sealing layer 22 consisting of 30% of high-density polyethylene having the properties listed in the table shown in Fig . 8 ( e . g . , in the speci fic exemplary application of the table in Fig . 9 , HDPE HTA002 from ExxonMobilTM) and 70% of an ethylene-hexene copolymerhaving the features listed in the table of Fig. 7 (e.g., in the exemplary application of Fig. 9, it is the plastomeric resin VLDPE ExactTM 3236 from ExxonMobilTM) .

[0085] Preferably, with reference to the exemplary application of the table of Fig. 9, in the upper wall 12, the sealing layer 22 extends for 25% of the total thickness of the upper wall 12, and the two layers 21, 22 of high-density polyethylene (an outer layer 20 and an intermediate layer 21) occupy the remaining 75%, preferably the outer layer 20 occupies 25% of the thickness and the intermediate layer 21 50% of the thickness of the upper wall 12.

[0086] Preferably, the upper wall 12 of the exemplary application has a thickness of 300 microns.

[0087] In one exemplary application, the breakable wall 14 consists of a polymeric sheet 4 comprising two layers 44 of high-density polyethylene having the properties listed in the table shown in Fig. 5 (e.g., according to the application shown in Fig. 9, it is HDPE HTA108 from ExxonMobilTM) , and comprising a sealing layer 42 composed at 30% of an ethylene-hexene copolymer having the features listed in the table of Fig. 7 (e.g., as indicated in the table of the exemplary application of Fig. 9, it is VLDPE ExactTM 3236 plastomeric resin from ExxonMobilTM) and 70% high-density polyethylene havingthe features listed in the table shown in Fig . 5 ( for example , in the application of Fig . 9 , it is HDPE HTA108 from ExxonMobilTM) .

[0088] In an alternative embodiment , in the breakable wall 14 , the high-density polyethylene is replaced with a 1- octene ethylene copolymer having the properties listed in the table of Fig . 6 , for example it is DowlexTM 2006G from DowTM .

[0089] Preferably, with reference to the exemplary application of Fig . 9 , in the breakable wall the sealing layer 42 extends for 15% of the total thickness of the polymeric sheet 4 , and the two layers indicated as a whole by the reference sign 44 ( an outer layer and an intermediate layer ) of high-density polyethylene with a low transverse elongation at break 3% or ethylene 1- octene copolymer occupy the remaining 85% , preferably the outer layer occupies 35% of the thickness and the intermediate layer 50% of the thickness of the polymeric sheet .

[0090] Preferably, the breakable wall of the example has a thickness of 30 microns .

[0091] It is speci fied that in the tables shown in Fig . 5 to 8 , the indication "ExxonMobil method" refers to test methodologies developed by the manufacturer for di f ferent materials preferably used for this application purpose .The person skilled in the art is aware of these methodologies .

[0092] Furthermore , the present invention also relates to a method for manufacturing a blister pack 1 according to the present invention, comprising the following steps :- providing an upper wall 12 for a blister pack, said upper wall 12 having one or more at least partially accessible containment chambers 3 , and providing a polymeric sheet 4 according to the present invention; filling the one or more chambers 3 with a pharmaceutical or nutraceutical or cosmetic or food product ;- heat-sealing the polymeric sheet 4 to the upper wall 12 so as to surround and seal such one or more chambers 3 .

[0093] In one embodiment , the method also provides for a primary thermoforming step of the upper wall 12 for making said one or more chambers . In one embodiment , the polymeric sheet 4 may also be thermoformed to make part of the volume of said one or more chambers 3 .

[0094] Innovatively, the present invention solves the drawbacks of press-through blister packs that are typical of the prior art .

[0095] Advantageously, the present invention has a considerably reduced environmental impact compared to the solutions available today . In fact , the blister packaccording to the present invention comprises portions made from materials belonging to the same class or even the same material and is therefore suitable for being di f ferentiated in a single piece and allows a disposal that is suitable for the increasingly stringent need for sustainability and ecology .

[0096] Advantageously, the blister pack according to the present invention is recyclable according to current regulations (EN 13430 ) .

[0097] Advantageously, the blister pack according to the present invention is characteri zed by excellent ease of opening, which is comparable to that provided by current solutions using aluminum . Therefore , this blister pack may be easily opened even by patients with limited mobility .

[0098] The ease of opening was evaluated by the Applicant on the basis of pressure dynamometric tests in which the pressure at the time of fracture with a known surface tip is evaluated, performed both on samples of the material and on the finished product , according to the most common test methodologies for so-called push-out tests .

[0099] The Applicant has carried out several experimental tests on press-through blister packs according to the present invention, to evaluate the breakability thereof and veri fy that such blister packs indeed exhibit easy-tear properties .

[0100] The tests were carried out with pressing probes with a diameter of approximately 12 mm .

[0101] All of the tests performed returned fracture force values well below the upper speci fication limit (UPS ) . This maximum acceptable threshold value , set at S ON, has been empirically identi fied through various experimental tests and essentially corresponds to the maximum force required to break the same surface of blister pack lids made in the materials of prior art .

[0102] All the tests performed gave values lower than this acceptable maximum value , and in particular fracture forces between 20 N and 26 N . These values are advantageous with respect to known blister packs , especially mono-material .

[0103] Advantageously, therefore , the Applicant has veri fied that the synergistic combination of the choice of materials and the post- filming stretching process gives the polymeric sheet used to make the breakable wall the features that make it even more easily breakable and at the same time resistant and compatible with the contents .

[0104] According to an even further advantage , the polymeric sheet may be easily opened even when intact and does not require the presence of pre-cuts or incisionsthat facilitate the breaking thereof .

[0105] Thus , advantageously, the blister pack according to the present invention ensures long-term integrity and is safe against any contamination .

[0106] According to a further advantage , the blister pack according to the present invention is suf ficiently impermeable to oxygen and protects the contents from premature degradation .

[0107] According to a still further advantage , the blister pack according to the present invention is suitable for being assembled in plants already in use for current commercial solutions and by the thermoforming, filling, and heat-sealing processes currently used for solutions involving the use of other materials .

[0108] Advantageously, the polymeric sheet may be processed in such plants to allow the heat-sealing of the breakable wall to the upper wall of the blister pack at temperatures generally between 100 ° C and 160 ° C, i . e . at temperatures that are about 20% lower than the temperatures necessary to perform the assembly of the blister packs currently on the market , such as those made of aluminum . This clearly has a considerable energy savings and consequently makes the proposed solution even more sustainable .

[0109] It is clear that , to the embodiments of theaforesaid blister pack and the aforesaid polymeric sheet , a person skilled in the art , in order to meet speci fic needs , could make variations or substitutions of elements with functionally equivalent ones .

[0110] Such variants are also included within the scope of protection as defined by the following claims . Moreover, each variant described as belonging to a possible embodiment may be implemented independently of the other variants described .

Claims

CLAIMS1. A press-through blister pack (1) for the pharmaceutical or nutraceutical or cosmetic or food sector, comprising an upper wall (12) and a breakable wall (14) mutually constrained so as to form and tightly seal one or more containment chambers (3) suitable for housing pharmaceutical or nutraceutical or cosmetic or food products, for example in the form of tablets, powders, liquids or hard or soft capsules, wherein the upper wall (12) and the breakable wall (14) are both made of a polymeric material, and wherein the breakable wall (14) comprises a polymeric sheet (4) mainly extending along a longitudinal direction and along a direction transverse to said longitudinal direction, said polymeric sheet (4) comprising a polymer of the polyethylene family characterized by an elongation at break in the transverse direction of less than or equal to 15% and by a tensile strength at break in the transverse direction less than or equal to 37 MPa, where the elongation at break and the tensile strength are measured according to the ASTM D882 standard.

2. Blister pack (1) according to claim 1, wherein the polymer of the polyethylene family is a 1-octene ethylene copolymer or an HDPE (high-density polyethylene) and hasa density between 0.940 and 0.965 g / cm3calculated according to the ASTM D792 standard.

3. Blister pack (1) according to claim 1 or 2, wherein the polymeric sheet (4) is mono-oriented in the longitudinal direction.

4. Blister pack (1) according to claim 1 or 2 or 3, wherein the polymeric sheet (4) is multilayer and comprises a layer of 1-octene ethylene or HDPE and a sealing layer (42) , preferably co-extruded.

5. Blister pack (1) according to claim 4, wherein the sealing layer (42) comprises an ethylene-hexene copolymer having a density less than 0.910 g / cm3(ASTM D792) , a melt index ( 190 °C / 2.16kg) between 2 and 4 g / lOmin (ASTM D1238) , and a peak melting temperature less than or equal to 114°C, preferably measured by differential scanning calorimetry (DSC) , preferably according to the ISO11357 standard .

6. Blister pack (1) according to claim 4 or 5, wherein the sealing layer (42) has a thickness of 10% with respect to the total thickness of the polymeric sheet (4) .

7. Blister pack (1) according to any one of the preceding claims, wherein the breakable wall (14) has a thickness less than or equal to 60 microns, more preferably less than or equal to 25 microns, even more preferably equalto 25 microns.

8. Blister pack (1) according to any one of the preceding claims, wherein the upper wall (12) has a thickness between 300 microns and 400 microns, endpoints included.

9. Blister pack (1) according to any one of the preceding claims, wherein the upper wall (12) comprises a coextruded polymeric layer assembly (2) , comprising HDPE (high-density polyethylene) and VLDPE (very low-density polyethylene) , with a thickness ratio of HDPE to VLDPE between 1.5 and 19, endpoints included.

10. Blister pack (1) according to claim 9, wherein the polymeric layer assembly (2) is a film comprising two layers (20, 21) of HDPE (high-density polyethylene) and a sealing layer (22) of ethylene-hexene copolymer.

11. Blister pack (1) according to any one of the preceding claims, wherein the polymeric sheet (4) is filled with one or more additives which reduce permeability to oxygen and humidity, said one or more additives being selected from the group comprising: clay crystallites, talc, graphene or inorganic compounds having a lamellar structure.

12. A polymeric sheet (4) for manufacturing a breakable wall (14) for a press-through blister pack (1) , wherein said polymeric sheet (4) predominanty extends along a longitudinal direction and along a directiontransverse to said longitudinal direction, said polymeric sheet (4) comprising a polymer of the polyethylene family characterized by an elongation at break in the transverse direction less than or equal to 15%, where the elongation at break in the transverse direction is calculated by the method according to the ASTM D882 standard.

13. A method for manufacturing a blister pack (1) according to any one of claims 1 to 11, comprising the following steps:- providing an upper wall (12) for a blister pack, said upper wall (12) having one or more at least partially accessible containment chambers (3) , and providing a polymeric sheet (4) according to the present invention; filling the one or more chambers (3) with a pharmaceutical or nutraceutical or cosmetic product;- heat-sealing the polymeric sheet (4) to the upper wall (12) so as to surround and seal such one or more chambers

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