IMPROVED CONTAINER, SHEET MATERIAL FOR MAKING SUCH CONTAINER, AND METHOD FOR MAKING SUCH CONTAINER

Description

IMPROVED CONTAINER, SHEET MATERIAL FOR THE CONSTRUCTION OF SUCH A CONTAINER, AND METHOD FOR MAKE THIS CONTAINER On behalf of: Romeo Bandini DESCRIPTION OF THE INVENTION The present invention falls within the sector of the production of food containers. or beverages and specifically concerns an improved container, a sheet material for the making of such a container, and a method for making such a container. 10 A container for food or drinks is known consisting of a perimeter wall obtained from a sheet material of the so-called polylaminate type and defining a volume interior of the container intended to hold food or drink. The perimeter wall, typically, it is welded with hot air or induction or it is glued longitudinally to form a cylinder, and is welded transversely by 15 electromagnetic induction at its welding portions at the bottom and head ends, such weld portions bearing joining elements. Each junction element comprises a laminar conductive layer and two adjacent heat-sealing layers: heating the conductive layer causes the fusion of the heat-sealing layers that bind to the perimeter wall, creating the 20 welding of this. Once the welding is completed, the edge of the conductive layer of the elements of junction remains uncovered by the heat-sealing layers and in contact with the volume inside the container. One disadvantage of the known container is that the conductive layer of the joint elements come into contact with the food or drink inside the 25 container: the container material can therefore be affected by food or drink, Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) especially if acidic, degrading, increasing the risk of breakage of the weld, and reducing the useful life of the container itself and, therefore, the shelf-life of the product in it contained. Another disadvantage of the known container is that the conductive layer 5 of the joint elements, affected by food or drink, can release substances or particles in the food or drink itself, altering the organoleptic properties of the food or drink and with potential risks of intoxication or poisoning of a user of the food or drink. An object of the present invention is to propose an improved container in 10 in which the two heat-sealing layers of each joining element are mutually welded or connected in a single body at least along the edge of the element of the junction itself adjacent to the internal volume, thus separating the conductive layer from the internal volume and from the food or drink. Another object of the present invention is to propose a safe and 15 durable, in which the welds are not affected by the food or drink contained and not release substances or particles of conductive material into the latter. A further object of the present invention is to propose a sheet material for the realization of the improved container, in which at least one of the layers heat sealable includes a surplus of heat sealable material connected or adapted to 20 solder with the opposite heat seal layer to isolate the edge of the conductive layer from the internal volume of the container that will be formed from the sheet material. Another object of the present invention is to propose a method for making the improved container from such sheet material, in which during welding each weld portion is also compressed from the outside to cause the 25 welding of an excess of heat-sealing material of at least one of the layers Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) heat seal to the opposite heat seal layer, isolating the edge of the layer conductive of each junction element from the internal volume of the container obtained. The features of the invention are highlighted below with particular 5 reference to the attached drawings in which: - Figure 1 illustrates a top view of the improved container under consideration. present invention; - Figure 2 shows a sectional view along the II-II plane of the container in Figure 1; 10 - Figure 3 shows an enlarged view of a portion of the container of Figure 2; - Figure 4 shows a partial top view of the sheet material being examined. present invention; - Figure 5 shows a partial, enlarged sectional view along the VV plane not to scale of the sheet material in figure 4; 15 - Figure 6 illustrates a partial sectional view of the sheet material of Figure 5 following a welding condition; - Figures 7 to 12 show partial sectional views and not to scale of the respective variants of the sheet material in figure 5; - Figure 13 shows a partial top view of a variant of the material in 20 figure sheet 4; - figure 14 shows a partial sectional view along the XIV-XIV plane, enlarged and not to scale of the sheet material variant of figure 13. With reference to figures 1 to 14, 1 indicates the improved container. subject of the present invention. 25 In its preferred embodiment, the container 1 has an internal volume 4 Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) defined by a perimeter wall 3, which is made of at least one material in sheet 51 and may optionally include a through opening, initially closed from a removable or breakable seal, possibly bearing a spout or a reinforced edge with an associated cap. 5 The perimeter wall 3 has a box-shaped parallelepiped, cylinder, parallelepiped with rounded corners, pyramid, or other shape suitable for containing food or a drink. The perimeter wall 3 typically has a longitudinal weld, performed by hot air, induction or other heat sealing method, or by gluing, during the container manufacturing process before filling 10 of the latter, and is welded by electromagnetic induction at at least a welding portion 55 of the sheet material 51 and, consequently, of the container 1. Preferably, the container 1 is induction welded at at least two 55 transverse welding portions, one at a bottom portion and the other at 15 an opposite head portion of container 1 itself. Optionally, container 1 also includes one or more longitudinal welding portions 55 suitable for creating the longitudinal welding mentioned above. The sheet material 51 comprises a support means 52 which constitutes the main structural component of perimeter wall 3 and container 1. 20 The support means 52 comprises a support layer 53 which in turn comprises, or is made from, paper, cardboard, microfibrillated cellulose (MFC), plastic, polyethylene, polymeric material, wax, and / or other material or compound or fibre-based material; such material, compound or fibre may be vegetal and / or synthetic. Alternatively or in addition, the support layer 52 is composed of a 25 coupled, multi-coupled or mixed material comprising one or more of the materials Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) such as plasticized paper, waxed paper, polymer-blended paper or MFC. The basic function of the support layer 53 is to provide support structural to container 1 once formed, and if coupled or mixed with materials hydrophobic or waterproof makes the support medium 52 waterproof at the same time 5 liquids and / or gases to preserve the food or drink inside the container 1. In addition, the material of the support layer 53 is preferably such as to allow the fixing for welding heat-sealable materials; an example of such material is the so-called MFC. Preferably, to increase the waterproofing effect, the support medium 52 further comprises at least one coating layer 54 acting as a barrier, 10 coupled and / or laminated to the support layer 53 on the side of this which, once formed container 1, is located adjacent to the internal volume 4. The coating layer 54 comprises a heat-sealable material suitable for the welding as will be better explained below, i.e. capable of softening or melting when subjected to sufficient heat. Furthermore, heat-sealing material is not 15 not susceptible to damage or deterioration by food or drink that may be placed in it container 1, at least for the shelf-life of container 1 itself. Such a heat-sealing material is preferably polyethylene (PE), or comprises at least one of polyethylene (PE), low density polyethylene (LDPE), medium density polyethylene (MDPE), linear low density polyethylene (LLDPE), polypropylene (PP), or similar, 20 with possible addition of one or more metallocenes and / or microfibrillated cellulose. Some variants of the container 1 provide that the support means 52 comprises multiple layers of coating 54 superimposed, for example since each layer constitutes a barrier selectively for liquids or gases, or because a layer constitutes a bridge or an adhesive to join the two adjacent layers. Obviously, even in this 25 case it is important that the last coating layer 54, i.e. the one in contact with the Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) internal volume 4 and the food or drink, both in heat-sealable material. Of course, the support layer 53 can also be further equipped with one or more cladding on the outside of the perimeter wall 3. Each welding portion 55 of the container 1 is provided with at least one 5 corresponding joining element 57 suitable for allowing induction welding electromagnetic of the welding portion 55 itself. More joining elements 57 can optionally affect the same portion of the weld 55, provided that the welding achieved thanks to them extends to the entire welding portion 55 sealing it completely. 10 Each junction element 57 comprises a laminar type conductive layer 59 and of any shape but preferably rectangular, having a perimeter edge 63 corresponding to the thickness of the conductive layer 59 itself and included between a first face 61 and an opposite second face 62 of the conductive layer 59. The conductive layer 59 is made of, or comprises, one or more conductive materials 15 electric, preferably aluminum, and / or other metallic materials, carbon-based, conductive polymers, graphene, conductive inks, or similar; in this way, when irradiated by an electromagnetic field of adequate frequency and intensity, the layer conductive 59 heats up to perform induction welding. A first heat-sealing layer 71 of the joining element 57 adheres to the first 20 face 61 of the conductive layer 59, and a second heat-sealing layer 72 is adherent on the second face 62. Such first heat-sealing layer 71 and second heat-sealing layer 72 are made in heat-sealable material, equal to or compatible with fusion welding with the backing layer material 53 or with the heat-sealing layer material 25 of coating 54. In particular, the heat-sealing material comprises Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) preferably at least one of polyethylene (PE), low density polyethylene (LDPE), medium density polyethylene (MDPE), linear low density polyethylene (LLDPE), polypropylene (PP), one or more metallocenes, or similar polymeric and non-polymeric materials. More in detail, the heat-sealing material preferably comprises one or more of such 5 polymeric materials added or mixed with one or more metallocenes. In fact, the first heat-sealing layer 71 and the second heat-sealing layer 72 of each joint element 57 are welded to the support means 52, constituting the actual welding of the container 1. The conductive layer 59 between them, moreover, It advantageously provides a mechanical or structural reinforcement of the weld 10 same. More specifically and preferably, at least one of the first heat-sealing layer 71 and the second heat-sealing layer 72, preferably both, is sealed with the layer of lining 54 with which the support means 52 is equipped on the side of the internal volume 4. This welding is a single body and therefore complete and gas and liquid tight, being 15 heat-sealing materials of the heat-sealing layers 71, 72 and of the coating layer 54 welded and joined together by fusion at the welding stage. In a variant of the container 1, at least one of such heat-sealing layers 71, 72 is consisting of the cladding layer 54 itself, coinciding with the latter. Therefore, once the welding is done, the coating layer 54 adheres 20 solidly to the first face 61 and / or to the second face 62 of the conductive layer 59 of each joint element 57, constituting the first 71 and / or second 72 layer heat sealable. For example, each connecting element 57 is initially provided with only the first heat-sealing layer 71, which is used to fix the element by welding 25 junction 57 to the coating layer 54; during the formation process and Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) welding of the container 1, the support means 52 is bent in such a way that the coating layer 54 of the initially free weld portion area 55 comes into contact with the second face 62 of the said connecting element 57; Induction heating of the conductive layer 59 causes melting or fusion 5 of the coating layer 54 in that area of ​​the welding portion 55, and therefore the coating layer 54 adheres and bonds to the conductive layer 59, forming the second heat-sealing layer 72 of the joining element 57. In another variant of the container 1, when the support layer 53 of the medium support 52 is not associated with any coating layer 54, the first layer 10 heat seal layer 71 and the second heat seal layer 72 are fusion welded and adhere completely to the support layer 53, for example because the latter contains a percentage of heat-sealing material which, in addition to acting as a barrier waterproof, guarantees such adhesion and therefore the welding. For each joint element 57 adjacent to the internal volume 4 of the container 1, 15 i.e. for each bottom and butt weld, at least one between the first heat sealing layer 71 and the second heat sealing layer 72 is welded with the opposite second heat-sealing layer 72 or first heat-sealing layer 71, respectively, in correspondence of at least one section of the perimeter edge 63 of the conductive layer 59 of such junction element 57 adjacent, i.e. bordering or facing, the volume 20 inside 4 of container 1, covering said section of the perimeter edge 63 and so separating and keeping insulated the conductive layer 59 of the joining element 57 from the internal volume 4. This advantageously allows to solve the technical problem of isolating the layer conductive 59 from the food or drink contained in container 1, to prevent the 25 conductive material can be released into food or drink contaminating it, and for Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) prevent food or drink, particularly acidic ones, from damaging the conductive layer 59 same with potential welding failure. At the same time, the application of the conductive material, necessary for induction welding, to the support means 52 remains simple and quick thanks to the selected shape of the 5 laminar conductive layer 59, which with the first 71 and second 72 conductive layers forms a connecting element 57; moreover, the welding of the container 1 results robust due to the conformation of the connecting element 57. Variants of container 1 provide that the first heat-sealing layer 71 and the opposite second heat-sealing layer 72 of each joining element 57 are mutually 10 connected in a single body at least along the said section of the perimeter edge 63, meaning that these two heat-sealing layers 71, 72 cover the edge perimeter 63 even before the actual welding is carried out. In any case, the welding or connection 73 between the two heat-sealing layers 71, 72 is at least watertight liquids. 15 In other variants of the container 1, the perimeter edge 63 of the conductive layer 59 of each joint element 57 is covered by the welding or connection between the two opposite heat-sealing layers 71, 72 also in other sections besides the one adjacent to the internal volume 4, or it can also be completely covered. More specifically, the welding or connection 73 i.e. the junction between the first layer 20 heat-sealing layer 71 and the second heat-sealing layer 72 covers said edge section perimeter 63 of the conductive layer 59 adjacent to the internal volume 4 of the container 1 with a thickness preferably of at least 1 μm, preferably between in the range from 1 μm to 2 mm, more preferably in the range of 2 μm to 1 mm, more preferably in the range from 3 μm to 50 μm. The thickness of 25 such coverage of the perimeter edge 63 is preferably uniform or nearly uniform Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) along all or most of the covered stretch, but it may also be not uniform without compromising the insulation effect provided by the conductive layer 59, provided that the coverage is continuous, i.e. without interruptions in the said section. In light of the above, it is clear that even a sheet material 5 51 suitable for constituting the perimeter wall 3 of the container 1 form the object of the present invention. In its preferred embodiment, the sheet material 51 comprises a support means 52 and carries one or more regions of any geometric shape, each region being destined to the creation of a respective container 1 10 at least by electromagnetic induction welding of at least one of its parts predetermined welding portion 55, preferably of at least two portions of 55 transversal welding respectively at a bottom portion and at an opposite head portion of the container 1 itself. A welding portion 55 is also preferably intended to create a longitudinal weld of the wall 15 perimeter 3 of container 1, which is otherwise closed longitudinally by another heat-sealing or gluing type. The sheet material 51, therefore, may consist of one or more sheets (e.g. rectangular) each provided with one or more regions to create a corresponding number of containers 1, or preferably it is of the reel-wound tape type, 20 with such regions arranged in a serial and continuous fashion along the ribbon. The support means 52, in turn, comprises at least one support layer 53 comprising or based on paper, cardboard, microfibrillated cellulose, plastic, polyethylene, polymeric material, wax, and / or other material or compound or material fibre-based, vegetable and / or synthetic. 25 Optionally but preferably, the support means 52 further comprises at least Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) a coating layer 54, coupled and / or laminated to the support layer 53 by part of this which, once container 1 has been formed, is adjacent to the volume interior 4. While the support layer 53 primarily provides structural support to the 5 sheet material 51 and the containers 1 that will be obtained from it, the layer of 54 coating has a waterproofing or barrier function to preserve food or drinks inside the containers 1 themselves. Each of said welding portions 55 is provided with at least one respective or corresponding joining element 57 for electromagnetic induction welding. 10 Each junction element 57 in fact comprises a laminar conductive layer 59 of any shape but preferably rectangular, having a perimeter edge 63 corresponding to the thickness of the conductive layer 59 itself and included between a first face 61 and an opposite second face 62 of the latter. The conductive layer 59 is preferably made of aluminum, or consists of or is based on 15 other electrically conductive metallic or carbon-based material, polymers conductive, graphene, conductive inks, or similar. The thickness of the layer conductive 59 is preferably uniform and included, by way of example but not limited to limitatively, in the range from 0.5 μm to 100 μm, more preferably from 3 μm to 50 μm, even more preferably from 5 μm to 10 μm, with preferred thicknesses in the range 20 from 6 μm to 9 μm. A conductive layer 59 of graphene can for example have thicknesses even lower than 1 μm, given the very high value of its breaking load. Where the sheet material 51 is a sheet or strip comprising multiple regions, a welding portion 55 with the respective joining element(s) 57 can optionally extend to two adjacent regions of the same sheet or tape, such as 25 illustrated in figure 4. Once the two have been formed and welded Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) corresponding containers 1, these will be separated with a cut along that portion of welding 55 (for example, performed along the dashed centerline in the same figure 4), and each of them will have its own portion of welding 55 welded, meaning a part (e.g., half) of the original weld portion 5 55 shared. A first heat-sealing layer 71 of each joining element 57 adheres to the first face 61 of the latter and is fixed to the support means 52, being to this welded (for example, by fusion through the application of heat or by induction), glued or otherwise applied. 10 The sheet material 51 further comprises a second heat-sealable layer 72 which preferably it is already applied and adheres to the second face 62 of the conductive layer 59 of each respective joint element 57, at least in one condition of welding of the sheet material 51 itself. In some variants of the sheet material 51, the second heat-sealable layer 72 is 15 applied and / or is intended to adhere to the second face 62 of the conductive layer 59 of a respective or of each joint element 57 only at or near or immediately prior to forming and welding the sheet material 51 for make container 1. The first heat-sealing layer 71 and the second heat-sealing layer 72 are made of 20 heat-sealing material preferably comprising at least one of polyethylene (PE), low density polyethylene (LDPE), medium density polyethylene (MDPE), linear low density polyethylene (LLDPE), polypropylene (PP), one or more metallocenes, or similar. More preferably the heat-sealing material comprises at least one of said polymers added or mixed or combined with one or more metallocenes. 25 The addition of metallocene advantageously allows to improve the sealing of the Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) fusion welding which will be carried out subsequently. If foreseen, the layer of coating 54 is made of heat-sealing material or plastic (for example polyethylene) or other barrier material suitable for fusion welding with the heat-sealable material of the heat-sealing layers 71, 72. If the support medium 52 is without the layer 5 of coating 54, the material of the heat-sealing layers 71, 72 is such that it can be used in any case to be welded to the backing layer material 53. The thickness of the first 71 and second 72 heat-sealing layers is preferably in the range from 1 μm to 1 mm, preferably from 2 μm to 400 μm, plus preferably from 3 μm to 50 μm; within the ranges mentioned, the two layers 10 heat sealants 71, 72 can have the same or even significantly different thickness. At least one of the first heat-sealing layer 71 and the second heat-sealing layer 72 includes a surplus of heat-sealing material which, at least in the condition of welding, is connected with the opposite second heat-sealing layer 72 or first layer heat-sealing 71, respectively, at least one section of the edge 15 perimeter 63 of the conductive layer 59. This excess is here generally understood as a quantity of heat-sealing material additional, that is, an overabundance of such material, compared to the quantity essentially necessary or sufficient to cover or coat the corresponding first face 61 or second face 62 of the conductive layer foil 59. 20 Whatever shape you choose, the excess material is still sufficient to connect the first 71 and second 72 heat-sealing layers to each other in such a way that such connection, welding, coupling or fusion continuously covers said perimeter edge section 63. Preferably the excess material heat-sealing, in addition to covering the predetermined sections of the perimeter edge 63, 25 adheres and welds to these in such a way as to leave no empty spaces, i.e. spaces filled with air. Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) contact with the conductive layer 59, further reducing the deterioration of the latter for example by oxidation. In particular and preferably, the surplus can then take the form of a geometric extension, i.e. of one or more edges 75 of the heat-sealing layer 71, 5 72 which mainly extend beyond the perimeter of the conductive layer 59 so to be able to follow and cover the perimeter edge 63 towards the opposite face. This is equivalent to say that the said excess heat-sealing material of the first heat-sealing layer 71 and / or of the second heat-sealing layer 72 is such that, at least in the condition of weld, extends beyond the perimeter of the respective first face 61 or second face 10 62 in correspondence with said at least one section of the perimeter edge 63. The length of the protruding edge 75 of the geometric excess with respect to the perimeter of the corresponding face 61, 62 is at least 1 μm, preferably from 1 μm to 2 mm, more preferably from 2 μm to 1 mm, even more preferably from 3 μm to 50 μm, depending however also on the thickness of the conductive layer 59 of which it is 15 it is necessary to cover the perimeter edge 63 and the thickness of heat-sealing material with which you intend to cover this edge. For example, as illustrated in Figure 7, the second heat-seal layer 72 adheres to the second face 62 of the respective conductive layer 59 and has a thickness equal to the first heat-sealing layer 71, but extends in cantilever with its own excess beyond the 20 perimeter of the conductive layer 59 at two opposite ends longitudinal of the latter. In the welding process, this excess softens or melts down to cover these sections and joins with the first layer heat seal 71 at the perimeter of the first face 61. Similarly, the first heat-sealing layer 71 may have an excess of 25 heat-sealing material that extends beyond the perimeter of the respective first face Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) 61, as illustrated in figure 8. Possibly, both the first heat-sealing layer 71 and the second layer heat-sealing 72 can extend in cantilever fashion beyond the first face 61 with the respective surpluses, for example as shown in Figure 9. 5 In a variant of the connecting elements 57, each of these comprises a own respective second heat-sealing layer 72 adherently fixed to the second face 62 of the conductive layer 59, and both the first heat-sealing layer 71 and the second heat-sealing layer 72 extend with respective excesses beyond the perimeter of the respective first face 61 or second face 62 and are mutually 10 joined and connected in a single body in correspondence with said at least one section of the perimeter edge 63. Referring for example to figure 10, the two layers heat-sealed 71, 72 are prosthetic and mutually connected along both sides longitudinal of the conductive layer 59, constituting a sort of sheath that wraps completely the conductive layer 59 insulating it. This excess sheath is 15 easily obtainable, for example, by coextrusion. Referring specifically to figures 11 and 12, another variant of these elements of junction 57 provides that each of these again includes a respective second heat-sealing layer 72 adhering to the second face 62, and that said at least one section of the perimeter edge 63 of the conductive layer 59 lies on a respective plane of 20 cut 8 inclined by a respective angle 9 not null with respect to the direction perpendicular to the first face 61 and to the second face 62 which, being the layer conductive 59 laminar, are almost flat and parallel. The perimeter edges of the first heat-sealing layer 71 and the second heat-sealing layer 72 also lie on said cutting plane 8 inclined along this section of the perimeter edge 63. 25 In other words, the sections of the lateral edge of a connecting element 57 affected by the Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) excess heat-sealing material is cut diagonally each along a respective cutting plane 8. It follows that, for each section, one between the first 71 and the second 72 heat-sealing layer protrudes from the perimeter of the respective first one 61 or second 62 face, while the opposite second 72 or first 71 heat-sealing layer 5 has a sharp edge that extends along the corresponding perimeter section of the second 62 or first 61 face. Considering the thicknesses and the typical stiffness of the materials, the edges along the perimeter edge 63 are flexible and in any case such for which do not affect the connection between the first 71 and the second 72 layer heat-sealing, and therefore the sealing of the weld and the insulation of the perimeter edge 10 63 same. Said angle 9 between each cutting plane 8 and the normal to the first 61 and second faces 62 is preferably in the range from 5° to 85°, preferably from 15° to 75°, more preferably 30° to 60°, more preferably 40° to 50°, and even more preferably it is around 45°. The values ​​indicated are intended in modulus, that is to say that 15 the angle 9 can be indifferently positive (conventionally measured in counterclockwise) or negative (measured clockwise). If the cut affects more than one section of the perimeter edge 63, for example two opposite longitudinal sections of it, the angle 9 of each corresponding cutting plane 8 can be the same or different. Figure 11 illustrates two planes of 20 cutting 8 longitudinal parallel, while in figure 12 the two cutting planes 8 are symmetrical or mirror-like with respect to a median longitudinal plane (not illustrated) that divides the conductive layer 59 perpendicularly. In all these cases, the flap 75 of the heat-sealing layer 71, 72 which protrudes is intended to soften or melt at the weld, covering the 25 corresponding section of the perimeter edge 63 until reaching the opposite layer Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) heat sealant 72, 71 to which it connects or welds, and at the same time adhering to the perimeter edge 63 which is therefore isolated. In some cases, the flap 75 could even if it doesn't get to weld with the opposite heat-sealing layer but it could reach first and weld with the support means 52 adjacent to the opposite face 5 61, 62. The cuts described can easily be obtained, for example, from a strip of conductive material, of width and thickness equal to the size respectively transverse and to the thickness of each conductive layer 59, coated on both sides with a heat-sealing material of the same thickness as the heat-sealing layers 10 first 71 and second 72, respectively. This tape is cut with a straight blade, oriented obliquely i.e. inclined according to the desired angle 9 with respect to the tape same, to obtain the individual connecting elements 57. Despite the extremely thin thickness of the connecting elements 57, and therefore of the starting tape, such a cutting method surprisingly allows to obtain 15 the connecting elements 57 as described with extreme simplicity. Alternatively or in addition to the geometric extension beyond the perimeter of the layer conductive 59, the excess heat-sealing material can take the form of a increased thickness of the first 71 and / or second 72 heat-sealing layer, as consequence of the addition of heat-sealing material in abundance. In the 20 welding condition, the conductive layer 59 heats up and causes softening or the fusion of the heat-sealing layers 71, 72; at the same time, to the joining element 57 a compression perpendicular to the first 61 and second 62 faces is applied which causes a crushing of the softened heat-sealing layers 71, 72; the excess of heat-sealing material is forced by this pressure to expand beyond the perimeter 25 of the first face 61 and / or of the second face 62, proceeding along one or more sections Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) of the perimeter edge 63 until it joins and connects or welds with the opposite heat-sealing layer 71,72 isolating said sections. An excess of this type is exemplarily illustrated in figure 5, where both the first 71 and second 72 heat-sealing layers comprise respective 5 excess heat-sealing material in thickness. Figure 6 shows a possible example of the mutual connection between these two layers. heat seal first 71 and second 72 along two opposite sections of the perimeter edge 63 following and as a consequence of the welding condition. In a variant of the sheet material 51, illustrated in particular in figures 13 and 14 10 It is expected that, prior to the welding condition, the second layer heat seal 72 of each joint element 57 is initially fixed to the vehicle of support 52, i.e. to the support layer 53 or to the coating layer 54 if present. The second heat-sealing layer 72 is fixed, thermally, mechanically, by gluing or otherwise similar, in the same welding portion 55 in the 15 which are also initially fixed the conductive layer 59 with the first layer heat-sealing 71 of the corresponding joining element 57. Their position reciprocal can be adjacent or even distant. This second heat-sealing layer 72 has a respective excess of material heat sealable to be welded with the first heat sealable layer 71 in the following way: 20 at a fold or winding of the support means 52 in a container forming phase 1, the second heat-sealing layer 72 is found exactly superimposed on the second face 62 of the corresponding conductive layer 59, with the related excess heat-sealing material extending beyond the perimeter of the second face 62; in correspondence with the welding condition, the second 25 heat-sealing layer 72 adheres and welds to the second face 62, as well as connecting and Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) to be welded to the first heat-sealing layer 71 along the perimeter edge 63 or sections of this, thus completing the welding of container 1. It is also expected that the perimeter of the second heat-sealing layer 72 initially fixed to the support means 52 is of identical dimensions to that of the layer 5 conductive 59, with the excess heat-sealing material assigned to the first layer heat sealable 71 or thick type. Naturally, a similar variant is also foreseen, where the heat-sealing layers first 71 and second 72 are reversed. Another variant of the sheet material 51 provides that the second heat-sealing layer 10 72 of each joint element 57 is not initially associated with the material in sheet 51 itself. Each second heat-sealing layer 72 is in fact applied to the corresponding second face 62 only during the production process of the container 1, for example shortly or immediately before the folding stage and forming of sheet material 51. The application is preferably done by 15 a thermal process, for example with a heated roller or piston that deposits the second heat-sealing layer 72 on the second face 62 making it adhere and welding it to the latter. In a further variant of the sheet material 51, not illustrated, the second layer heat seal 72 is constituted at least locally by the coating layer 54 itself 20 of the support means 52, which as already mentioned is coupled and / or laminated to the layer of support 53 of the support means 52 and comprises a heat-sealing material suitable to fusion welding with the material of the first heat-sealing layer 71. In this case, therefore, the coating layer 54 constitutes both a barrier for isolate the support layer 53 from the contents of the container 1, be a single second 25 heat-sealing layer 72 for all or for each joint element 57, at least Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) in the welding condition of the sheet material 51. In fact, this layer of coating is intended to face the second face 62 of the conductive layer 59 of each joint element 57 following the bending of the sheet material 51 and forming of the container 1, and to weld and adhere to such second face 62 in the 5 welding condition. The heating of the conductive layers 59, in fact, causes locally the softening or at least partial dissolution of the layer of coating 54, which thus adheres to each second face 62 and bonds to each first heat-sealing layer 71 wrapping and insulating almost the entire edge perimeter 63 of each conductive layer 59. Similarly, the first layer also 10 heat-sealing 71 itself can in this case be made up of localised portions of the coating layer 54, which in correspondence with the welding portions 55 It performs the function of keeping the conductive layer 59 fixed to the support medium 52. Again, this variant is equally applicable by reversing the layers 15 heat sealers first 71 and second 72. Another variant of the sheet material 51 provides that the conductive layer 59, first to make the weld, has its first face 61 (or, vice versa, the second face 62) fixed to the support means 52 by gluing or other means temporary. In this case, whatever the shape of the corresponding second layer 20 heat seal 72 (or, respectively, of the first heat seal layer 71) this is equipped with a respective excess of heat-sealing material which in correspondence of the welding condition covers the perimeter edge 63 and welds to the layer of cladding 54 around the perimeter of the first face 61, the cladding layer 54 locally taking on the role of the first heat-sealing layer 71. If the layer of 25 coating 54 is not provided but the conductive layer 59 is glued directly to the Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) support layer 53, the latter appears to represent or constitute at least locally the first heat-sealing layer 71 and is suitable for welding with the second layer heat seal 72, for example because the material of the backing layer 53 is or It also includes additives, fibres or other heat-sealable particles. 5 first heat-sealing layer 71 (or, by analogy, the second heat-sealing layer 72) in this case it turns out to be incorporated into the support means 52 itself. Excess heat-sealing material can be assigned to the first layer heat-sealing 71 in one of the ways already described, or it can be understood as part of the coating layer 54 itself, which continuously covers the entire layer of 10 support 52 necessarily extends beyond the perimeter of the second face 62 of all conductive layers 59. In the latter case, the thickness of the layer of coating 54 may optionally be increased to ensure that the layer of coating 54, once adhered to the second face 62 as a second layer heat seal 72, has enough material to cover the perimeter edge 63 and 15 connect to the first heat seal layer 71. A further object of the present invention is a method for making one or more containers 1 from a sheet material 51 as described above. The method essentially includes the following phases: - procure a sheet material 51 of the type comprising a support medium 20 52 and containing one or more regions of any geometric shape; - forming at least one region of the sheet material 51 to constitute a wall perimeter 3 which defines an internal volume 4 of a respective container semi-finished, such perimeter wall 3 being equipped with at least one predetermined welding portion 55 provided with at least one corresponding 25 joint element 57 suitable for electromagnetic induction welding; Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) - weld, by electromagnetic induction, the perimeter wall 3 in correspondence of each of its welding portions 55 thus obtaining a respective container 1. Each connecting element 57 comprises: 5 - a laminar conductive layer 59 which has a perimeter edge 63 included between its own first face 61 and its own opposite second face 62; - a first heat-sealing layer 71 adhering to the first face 61; - a second heat-sealing layer 71 adhering or intended to adhere to the second face 62. 10 Preferably, the sheet material 51 is in strip or reel form and bears a plurality of regions adjacently arranged in series. For each region there are preferably at least two welding portions 55 transversal to the tape, intended to create respectively a bottom weld and a butt weld of container 1. The support means 52 consists of a support layer 53 to which is preferably 15 coupled a coating layer 54 as a waterproof barrier. The first 71 and second 72 heat sealing layers are made of material heat-sealable, compatible with welding with the support medium 52 and possibly equal to the material of the cladding layer 54, if present. The forming phase involves bending, wrapping, or otherwise shaping a piece or 20 simultaneously multiple regions of the sheet material 51 to conform corresponding semi-finished containers. This phase may also include the welding, thermal or induction as explained below, or gluing longitudinal of two opposite edges of the sheet material 51 which, once wrapped or folded, they come to be adjacent or overlapping. 25 The phase of welding the perimeter wall 3 includes in particular the following steps: Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) - heating the conductive layer 59 of each junction element 57 by the irradiation of the same with an electromagnetic field of frequency and appropriate intensities, causing complete or partial fusion (i.e. a softening or localized melting) of the first heat-sealing layer 71 and of the 5 second heat-sealing layer 72 at least in correspondence with the conductive layer 59 itself, and consequently causing welding or strengthening the adhesion of the first heat-sealing layer 71 to the support medium 52, and / or the welding of the second heat-sealing layer 72 to the support medium 52 and / or to the second face 62; 10 - compress each portion of the weld 55, from the outside of the wall perimeter 3 of the semi-finished container, with direct pressure perpendicularly on both lateral faces of the respective element junction 57, causing excess heat-sealing material to be welded of the first heat-sealing layer 71 and / or of the second heat-sealing layer 72 at the 15 heat-sealing layer 72, 71 opposite at least one section of the perimeter edge 63 of the conductive layer 59 adjacent to the internal volume 4 of the container 1 thus obtained, separating and keeping the conductive layer isolated 59 from the internal volume 4 and its contents. The compressing step is preferably operated by at least one clamp or vice means 20 of width equal to or greater than the width, or transverse dimension, of the conductive layer 59, and is performed simultaneously or immediately following in the heat of the moment. The jaws of such a clamp or vice are preferably equipped with coils for electromagnetic induction. During the operation and execution of the method, the 25 a clamping device takes the semi-finished container at one or more of its Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) solder portions 55 and its coils irradiate the corresponding conductive layers 59, performing the heating step; the pressure of the jaws can eventually be increased according to a predetermined time profile during warm-up or following this, to cause in each welding portion 55 the connection and the 5 welding of the first 71 and second 72 heat-sealing layers, thus creating the step of compress. More precisely, the intensity of the pressure applied by the clamping means to each welding portion 55 in the compression step is preferably variable and electronically controlled according to a predetermined algorithm and as a function of 10 at least one of the following operational and design parameters: - amount of excess heat-sealing material, for example this being supplied in the form of a thickening of one or both heat-sealing layers 71, 72; - geometry of the excess heat-sealing material, e.g. depending on the 15 size of the flaps 75 of the heat-sealing layers 71, 72 protruding from the perimeter of the respective face 61, 62; - desired thickness of the weld or connection between the first 71 and the second 72 heat-sealing layer covering the affected perimeter edge sections 63; - temperature reached by the heat-sealing material as a result of the step 20 heat; - viscosity of the heat-sealing material melted totally or partially temperature reached during heating; - profile or temporal trend of the heating or of the field power electromagnetic radiated by electromagnetic induction; 25 - total duration of the compression phase or application of the Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) pressure. The intensity or value of the applied pressure is preferably between 2 2 2 in the range from 50 kg / cm to 1,000 kg / cm , preferably from 100 kg / cm to 750 2 2 2 kg / cm , more preferably from 200 kg / cm to 500 kg / cm , even more preferably 2 2 5 from 300 kg / cm to 360 kg / cm . Depending on the initial conformation of the sheet material 51, and in particular of the its joining elements 57, the heating step achieves the purpose of welding the heat-sealing layers first 71 and second 72 to the support medium 52 second possible slightly different operating sequences or procedures. Regardless of the 10 procedure followed, the final result is the desired welding of the portions of welding 55 of the perimeter wall 3 of each container 1. First, partial or complete melting of the heat-sealing layers 71, 72 occurs only locally and in correspondence with the area of ​​these in contact with a corresponding conductive layer 59 irradiated, and possibly just beyond the perimeter 15 of the latter thanks to the diffusion of heat by conduction through the material of the heat-sealing layers 71,72 themselves. This occurs in particular in the case described wherein the coating layer 54 constitutes a first 71 and / or second 72 layer heat sealing common to all the 57 joint elements: only the areas of the layer of 54 coating which after the forming of the semi-finished container face to 20 contact with the first 61 or second 62 face of a conductive layer respectively 59 will be locally affected by melting or softening. If initially both heat sealing layers first 71 and second 72 already adhere to the respective conductive layer 59 and each joint element 57 is already fixed to the support means 52, such as in Figures 5 to 12, then the pitch of 25 heating also involves welding the second heat-sealing layer 72 to the medium Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) of support 52 facing it following the forming. The simultaneous fusion of the first heat-sealing layer 71 possibly helps to reinforce the bond with the support medium 52. If initially the connecting element 57 is only removably attached to the means of 5 support 52, for example by temporarily gluing the first layer heat sealing 71, the heating step also causes a real welding robust and definitive of the first heat-sealing layer 71 to the support medium 52. However, if the second heat-sealing layer 72 is not initially associated adhering to the corresponding second face 62, two cases are possible: 10 - the second heat-sealing layer 72 is already applied and welded to the support medium 52, as for example shown in figures 13 and 14: then the heating step causes the adhesion and welding of the second heat-sealing layer 72 to the second face 62 of the corresponding conductive layer 59; - the second heat-sealing layer 72 is applied to the second face 62 during the 15 forming of the semi-finished container or immediately upstream: then the step to heat up causes the second heat-sealing layer 72 to be welded to both the support means 52 and said second face 62. In any case, the subsequent compressing step provides the desired insulation of the predetermined sections of the perimeter edge 63 of each conductive element 59 20 thanks to the connection between the first 71 and the second 72 heat-sealing layer, or between one of these and the coating layer 54 if this acts as the first 71 and / or second 72 heat-sealing layer. At least in the latest cases presented, but potentially also in other situations described, the procurement phase preferably includes the following steps: 25 - provide a support means 52 equipped with at least one welding portion 55; Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others) - fix a first heat-sealing layer 71 of at least one joining element 57, adhering to the first face 61 of the respective conductive layer 59, to the means of support 52 at each welding portion 55; - optionally, apply a second heat seal layer 72 to the second face 5 62 of each conductive layer 59 opposite the respective first face 61. In the variants where the starting sheet material 51 is expected to be equipped with 57 connection elements of the type with excess heat-sealing material lying on an inclined cutting plane 8, the procuring phase of the method can also include the step of obtaining the connecting elements 57 by cutting each of them from a strip 10 of conductive material, where the cut is made with a blade inclined with respect to the tape according to a desired angle 9 selectable and preferably included in the range from 5° to 85°, preferably from 15° to 75°, more preferably from 30° to 60°, more preferably 40° to 50°, and even more preferably around 45°. Usually, as is known, between the welding phases of the bottom and the head of each 15 container 1, the food or drink is introduced into the internal volume 4 of container 1 before sealing the latter. Optionally, the method also includes a step of cutting or incising at least one welding portion 55 included or shared between two adjacent containers 1 or consecutive, obtained from two adjacent or consecutive regions of the same 20 sheet material 51. The cutting or engraving is preferably made simultaneously or immediately following the compressing step, by means of of blades or tips for example associated with the jaws of the clamping device or operable in closure and between these. In this way the separation of each individual is obtained improved container 1 made. Agazzani & Associates Srl Engineer Giampaolo Agazzani (Registration no. 604BM) (for oneself and for others)

Claims

1) Improved container having a perimeter wall (3), consisting of at least one sheet material (51) comprising a support means (52), and defining an internal volume (4) of the container, the perimeter wall (3) being welded at least by electromagnetic induction at at least one welding portion (55) of the container (1); said at least one welding portion (55) being provided with at least one joining element (57) for induction welding; each joining element (57) comprising a conductive layer (59), having a perimeter edge (63) between a first face (61) and an opposite second face (62), a first heat-sealing layer (71) adhering to the first face (61), and a second heat-sealing layer (72) adhering to the second face (62); the first heat-sealing layer (71) and the second heat-sealing layer (72) being made of heat-sealing material;the container (1) being characterised in that, for each joining element (57) adjacent to the internal volume (4) of the container (1), at least one of the first heat-sealing layer (71) and the second heat-sealing layer (72) is welded or connected in a single body with the opposite second heat-sealing layer (72) or first heat-sealing layer (71) in correspondence with at least one section of the perimeter edge (63) of the conductive layer (59) adjacent to the internal volume (4) of the container (1), separating the conductive layer (59) from the internal volume (4).; 2) Container according to claim 1 characterised in that the support means (52) comprises a support layer (53) which comprises, or is based on, paper, cardboard, microfibrillated cellulose, plastic, polyethylene, polymeric material, and / or other vegetal and / or synthetic material or fibres, or Agazzani & Associati Srl Ing. Giampaolo Agazzani (Registered in the Register no. 604BM) (for himself and for others) which is composed of a coupled material comprising one or more of these materials. 3) Container according to claim 2 characterised in that the support means (52) further comprises at least one coating layer (54) coupled and / or laminated to the support layer (53) on the side of the internal volume (4) and comprising a heat-sealing material, where at least one of the first heat-sealing layer (71) and the second heat-sealing layer (72) is welded in one piece with the coating layer (54) or is constituted by the coating layer (54) itself. 4) Container according to any of the preceding claims characterised in that the welding or connection between the first heat-sealing layer (71) and the second heat-sealing layer (72) covers said portion of the perimeter edge (63) of the conductive layer (59) with a thickness of at least 1 μm, preferably in the range from 1 μm to 2 mm, more preferably in the range from 2 μm to 1 mm, more preferably in the range from 3 μm to 50 μm.5) Sheet material comprising a support means (52) and bearing one or more regions each intended for the production of a container at least by electromagnetic induction welding of at least one predetermined welding portion thereof (55); said at least one welding portion (55) being provided with at least one joining element (57) for induction welding; each joining element (57) comprising a conductive layer (59) having a perimeter edge (63) between a first face (61) and an opposite second face (62), and comprising a first heat-sealing layer (71) adhering to the first face (61) and fixed to the means of Agazzani & Associati Srl Ing. Giampaolo Agazzani (Registration n.604BM) (in itself and for others) support (52); the sheet material (51) comprising at least one second heat-sealable layer (72) adhering or intended to adhere to the second face (62) of the conductive layer (59) of a respective or each joining element (57) at least in a sealing condition of the sheet material (51); the first heat-sealable layer (71) and the second heat-sealable layer (72) being made of heat-sealable material; the sheet material (51) being characterised in that at least one of the first heat-sealing layer (71) and the second heat-sealing layer (72) comprises an excess of heat-sealing material which, at least in the sealing condition, is connected or is capable of being sealed with the opposite second heat-sealing layer (72) or first heat-sealing layer (71) at least one section of the perimeter edge (63) of the conductive layer (59). 6) Sheet material according to claim 5 characterised in that said excess heat-sealing material of the first heat-sealing layer (71) and / or of the second heat-sealing layer (72) is such that, at least in the sealing condition, it extends beyond the perimeter of the respective first face (61) or second face (62) in correspondence with said at least one section of the perimeter edge (63). 7) Sheet material according to claim 6 characterised in that each joining element (57) comprises a respective second heat-sealing layer (72) adhering to the second face (62), and said at least one section of the perimeter edge (63) of the conductive layer (59) lies on a respective cutting plane (8) inclined at a respective angle (9) with respect to the direction perpendicular to the first (61) and second (62) faces, with the edges of the first heat-sealing layer (71) and of the second heat-sealing layer (72) lying on said cutting plane (8) along said section, and with said angle (9) included in the range from 5° to 85°, preferably from 15° to 75°, more preferably from 30° to 60 ... 40° to 50°, even more preferably 45°. 8) Sheet material according to claim 5 or 6 characterised in that each joining element (57) comprises a respective second heat-sealing layer (72) adhering to the second face (62), and both the first heat-sealing layer (71) and the second heat-sealing layer (72) extend with respective excesses beyond the perimeter of the respective first face (61) or second face (62) and are mutually connected in a single body at said at least one section of the perimeter edge (63). 9) Sheet material according to claim 5, 6 or 8 characterised in that at least one of the first heat-sealing layer (71) and the second heat-sealing layer (72) is fixed to, or incorporated into, the support means (52), or consists of a covering layer (54) of the support means (52) coupled and / or laminated to a support layer (53) of the support means (52) itself and comprising a heat-sealing material. 10) Sheet material according to any of claims 5 to 9 characterized in that the thickness of the heat-sealable layers (71, 72) is in the range of 1 μm to 1 mm, preferably 2 μm to 400 μm, more preferably 3 μm to 50 μm, and the heat-sealable material comprises at least one of polyethylene (PE), low density polyethylene (LDPE), medium density polyethylene (MDPE), linear low density polyethylene (LLDPE), one or more metallocenes, or the like. 11) Method for making one or more containers (1) according to any of the Agazzani & Associati Srl Ing. Giampaolo Agazzani (Registered in the Register no. 604BM) (for himself and for others) claims 1 to 5, comprising the following steps: - procuring a sheet material (51) comprising a support means (52) and bearing one or more regions; - forming at least one region of the sheet material (51) to constitute a perimeter wall (3) which defines an internal volume (4) of a respective semi-finished container, and which is provided with at least one welding portion (55) provided with at least one joining element (57) for induction welding; - welding, by electromagnetic induction, the perimeter wall (3) in correspondence with the at least one welding portion (55) obtaining a respective container (1);each joining element (57) comprising a conductive layer (59), having a perimeter edge (63) between a first face (61) and an opposite second face (62), a first heat-sealing layer (71) adhering to the first face (61), and a second heat-sealing layer (72) adhering or intended to adhere to the second face (62); the first heat-sealing layer (71) and the second heat-sealing layer (72) being made of heat-sealing material;the method being characterised in that the welding phase comprises the following steps: - heating the conductive layer (59) of each joining element (57) with an electromagnetic field, causing the partial or complete melting of the first (71) and second (72) heat-sealing layer at least in correspondence with the conductive layer (59), and causing the welding of the first heat-sealing layer (71) to the support medium (52) and / or the welding Agazzani & Associati Srl Ing. Giampaolo Agazzani (Registered in the Register no. 604BM) (on his own behalf and for others) of the second heat-sealing layer (72) to the support medium (52) and / or to the second face (62);- compressing the at least one portion of the seal (55), from the outside of the perimeter wall (3), with a direct pressure on the at least one joining element (57), causing the sealing of an excess of heat-sealing material of the first (71) and / or second (72) heat-sealing layer to the opposite heat-sealing layer (72, 71) in correspondence with at least one section of the perimeter edge (63) of the conductive layer (59) adjacent to the internal volume (4) of the container (1), separating the conductive layer (59) from the internal volume (4).; 12) Method according to claim 11 characterized in that the compressing step is operated by at least one clamp means with a width equal to or greater than the width of the conductive layer (59), and is performed simultaneously with or immediately following the heating step. 13) Method according to claim 11 or 12 characterized in that the intensity of the pressure applied to the at least one sealing portion (55) in the compressing step is variable as a function of at least one of the quantity of excess heat-sealing material, geometry of such excess, viscosity of the molten heat-sealing material, temperature of the molten heat-sealing material, time profile of the heating, duration of the compressing step, and is preferably included in the range from 50 kg / cm2 to 1,000 kg / cm2, preferably from 100 kg / cm2 to 750 kg / cm2, more preferably from 200 kg / cm2 to 500 kg / cm2, even more preferably from 300 kg / cm2 to 360 kg / cm2. 14) Method according to any of claims 11 to 13 characterised by Agazzani & Associati Srl Ing. Giampaolo Agazzani (Registration No. 604BM) (on its own behalf and for others) in that the procuring step comprises the following steps: - procuring a support means (52) equipped with at least one welding portion (55); - fixing a first heat-sealing layer (71) of at least one 5-joint element (57), adhering to the first face (61) of the respective conductive layer (59), to the support means (52) in correspondence with each welding portion (55); - applying a second heat-sealing layer (72) to the second face (62) of each conductive layer (59).