IT202100027869A1 - SHEET FOR PRODUCING A WRAPPER FOR FOOD PRODUCTS OR SIMILAR, WRAPPER THAT INCLUDES IT AND PRODUCTION PROCESS OF THE LATTER - Google Patents

Description

SHEET FOR PRODUCING A WRAPPING FOR FOOD PRODUCTS

OR SIMILAR, ENCLOSURE INCLUDING IT AND PROCESS OF

PRODUCTION OF THE LATTER

TECHNICAL FIELD

The present invention refers to a sheet for forming a wrapper for example to contain food products, which allows the contents of the wrapper to be seen and possibly can be opened and closed.

The present invention also refers to a casing that can be made using this sheet and to a production process for this sheet and this casing.

STATE OF THE TECHNIQUE

Wrappers for containing a food product are known such that, once the food product is packaged in them, they are sealed in order to preserve the freshness of the product itself.

These traditional packages can have a portion equipped with a window to view the contents and/or can be equipped with an openable and resealable portion to allow, once opened, access to the product contained therein and, once closed, a seal against the passage of air to increase durability? of the product itself.

These traditional products are formed using sheets joined by heat sealing. In view of the ever-increasing sensitivity? to the recycling of production materials, especially the packaging of packaged products, these sheets include a layer of paper material and a layer of polymeric material which performs the dual function of providing waterproofness. to the paper layer and to create a window, where the paper layer provides an opening or a discontinuity.

Some traditional solutions require that the layer of polymeric material allows the creation of a base on which to adhere an openable and resealable flap, to allow access to the inside of the casing, for example for extracting the product.

This polymeric material can consist of PP, PE, PLA, PET, NY or biodegradable and compostable bioplastic such as that commercially known by the name Mater-Bi.

A drawback of these traditional wrappers is that they contain a high quantity of of this polymeric material which reduces its biodegradability? or compostability? compared to paper-only wrapping.

However, paper-only wrappers are not suitable for containing food products that may contain moisture. or oils and, in any case, do not allow to obtain such an air tightness as to guarantee high durability? of the product packaged in them.

Furthermore, to be equipped with a window for visibility? inside the casing, the products known today include at least one layer of polymeric material which closes an opening or? suddenly replaced the paper layer with which? mainly made of the casing, compromising easy recyclability? of the casing of which the paper material part should be separated from the polymeric material part, for their possible independent recycling.

Furthermore, the paper-only wrappers do not allow for an openable and resealable portion due to the tearing effect that the adhesive, holding the flap in the closed position, would cause on the sheet of paper constituting the wrapper.

SUMMARY OF THE FINDING

The problem underlying the present invention? therefore to reduce the environmental impact of traditional food packaging equipped with a viewing window inside.

The task of a sheet to produce a casing, of this casing and of a process for producing this sheet and this casing, according to the present invention, is? therefore to solve this problem.

Within this task, one purpose of the invention is? is to propose a sheet to form a casing to contain food products that allows visibility? of the inside of this wrapper, to a wrapper that includes this sheet and to a production process for this sheet and this wrapper that allows for greater biodegradability? of the casing compared to traditional solutions.

Within this task, one purpose of the invention is? that of making a sheet to produce a casing, a casing which includes it to a production process of the latter which allows to obtain a casing which allows the viewing of its contents and, possibly, which can also be opened and closed, whilst greatly increasing biodegradability? of the same. Another purpose of the present invention? is to propose a sheet to form a casing that allows visibility? of its contents, to a casing that includes this sheet and to a production process of this sheet and this casing that allows to significantly reduce the quantity? of plastic material present in the casing.

This task, as well as? these and other objectives which will appear better below are achieved by a sheet for producing a casing, a casing which includes it in a production process of the latter according to the attached independent claims.

Detailed characteristics of a sheet for producing a casing, a casing which includes it and a production process of the latter according to the invention are reported in the dependent claims.

Further characteristics and advantages of the invention will emerge more from the description of a preferred, but not exclusive, form of embodiment of a sheet for producing a casing, a casing which includes it in a production process of the latter according to the invention, supported by the proposed drawings for indicative and non-limiting purposes in the attached tables and listed below.

BRIEF DESCRIPTION OF THE DRAWINGS

- Figure 1 shows a schematic view of a casing according to the present invention, in perspective view;

- Figure 2 shows a schematic detail relating to a part of a sheet according to the present invention, in perspective view;

- Figure 3 shows an alternative implementation of the detail in figure 2, in perspective view;

- Figures 4 and 5 show alternative embodiments of a casing according to the present invention, in perspective view;

- Figure 6 shows a detail of the casing of figure 5, in perspective view;

- Figure 7 shows an exemplary diagram of implementation of a process according to the present invention.

DETAILED DESCRIPTION

With particular reference to the figures cited, ? generally indicated with 10 is a sheet to form a wrapper 100, which can be opened and closed if necessary, to contain food products that can be visible from the outside of the wrapper 100 itself.

The sheet 10, according to the present invention, generally comprises a membrane 1 which has a window 2 covered with a label 3 through which the contents and/or the interior of the envelope 100, once formed and filled, are displayed. visible. In detail, structurally sheet 10 includes:

- a membrane 1 made of cellulose material having a heat-sealable internal face 1a and an external face 1b; membrane 1? configured to create a wall of a casing 100 for a food product following a mutual heat sealing of portions of the membrane 1 which has an edge configured to define a discontinuity? in the wall, following a production of the casing 100, where this discontinuity? ? designed to form the window 2 to allow viewing inside the casing 100;

- a label 3, fixed to the membrane 1 by means of an adhesive 4 and overlapping the edge of the membrane 1 in such a way that, following production of the casing 100, the discontinuity? ? covered by an operational portion 3a of the label 3.

The operational portion, in the attached figures? exemplified so as to correspond in shape and size to window 2.

The 3rd operational portion? sufficiently resistant and transparent to retain 100 products housed inside the casing, at the same time allowing visibility. so that a user, seeing through the window 2 products contained in the casing 100, can evaluate for example the type and/or quantity? contained.

The operational portion 3a of label 3 is without sticker 4 or sticker 4? inactivated at the operational portion 3a or covered by a covering film.

The internal face 1a of the membrane 1 can? be made heat sealable by deposition, on the cellulose material, of a heat sealing adhesive which can be applied on membrane 1 in a quantity? between 1 g/m2 and 40 g/m2, in particular between 1 g/m2 and 10 g/m2 of adhesive in the liquid state and which, once dried, roughly halves its weight.

In particular, the heat-sealing adhesive can to be ? applied as an aqueous solution, for example on an ethylene/acrylic acid (EAA) basis such as the adhesive today known by the commercial code DH 336 from the Collano company.

Preferably, label 3 is made of polypropylene with a thickness between 10 and 200 microns, in particular preferably between 20 and 30 microns.

Label 3, by way of example and not as a limitation, can be made of poly-lactic acid, PLA, to increase compostability? of the casing 100 that includes it, or for example, in Polyethylene, PE.

Sticker 4 is preferably a glue material that allows the label 3 to be removed from the membrane 1 without causing flaking of the membrane 1 to make the casing 100 completely recyclable.

Or, the portion of membrane 1 on which ? coupled the label 1 can? be covered with a reinforcing material that can? for example consist of a lacquer and possibly can? be water-based, in particular it can? consist of the same heat-sealing adhesive with which ? the internal face 1a of membrane 1 is treated.

This reinforcing material can comprise or consist of a lacquer which retains the fibers of the cellulose material of the membrane 1 by compacting them, for example the same lacquer or other material used to make the first face 1a of the membrane 1 heat-sealable, possibly with the addition of a compound designed to facilitate separation, for example for example a wax, to limit excessive adhesion which could tear or flake the membrane 1 when separating the label 3 from the latter.

This reinforcing material can be spread either continuously, in bands or on the entire face 1a or 1b of the membrane 1, on which the label 3 is applied, or it can? be spread or applied in register selectively only where? label 3 is intended to be applied.

Label 3 is preferably shaped and sized so as to completely cover the window 2, extending on the edge of the membrane 1, which delimits the window 2, engaging an operating edge 1c on a minimum surface area to allow a sufficient seal to avoid spontaneous separation of the label 3 from the membrane 1, or possibly determined by a stress of the products contained in the casing 100.

Clearly, label 3 can? be fixed either to the internal face 1a or to the external face 1b of the membrane 1, depending on the contingent needs of implementing the present invention.

For example, it will be? It is preferable to apply label 3 to the internal face 1a where the aesthetic requirement prevails over the appearance of the casing 100 in which it will not be present. the part of the label 3 peripheral to the window 2 and fixed to the membrane 1 is visible.

Conversely, an application of the label on the external face 1b, so? that the envelope 100, once formed, has the label 3 on its outside, will be preferable where particular attention to recyclability is required? of the same thus facilitating? the taking of the label 3 and its separation from the membrane 1 when disposing of the casing 100 itself.

In the case, for example, of a label 3 made of compostable material, such as where it is made of PLA poly-lactic acid, therefore for which the separation of the label 3 from the membrane 1 is not required to reduce the environmental impact of the disposal of the casing 100, the application inside the internal face 1a of the membrane 1 can? be advantageous.

As exemplified in the attached figures, the edge of the membrane 1, which defines the window 2, can develop according to a closed trajectory shaped and sized in such a way as to define the window 2 in the membrane 1 suitable for allowing visibility? of the inside of the casing 100 following the production of the latter, for example the edge of the membrane 1 will be able to follow a curved trajectory, for example circular, ovoid or elliptical, or a polygonal trajectory. To facilitate separation from the membrane 1, the label 3 can present a detachment portion 31 which is without sticker 4 or where the sticker 4 is inactivated.

To make it easier for the user to grasp, the detachment portion 31 can extend from a perimeter of the label 3 so as to create an invitation tab, which can be grasped by a user and easily separated from the membrane 1, for example as visible in particular in figures 1-3.

In this way the user can easily lift the detachment portion 31, grab it and pull to force a separation of the label 3 from the membrane 1, for example to allocate the membrane 1 and the label 3 to different recycling chains. To obtain an openable and resealable envelope 100, the sheet 10 can present the membrane 1 having a first notch 11 which is shaped to define a first flap 12 that can be opened to form a first opening 21 which is passing through membrane 1; window 2 being provided on the first flap 12.

Similar to the example in figures 5 and 6, label 3 can be fixed to the external face 1b of the membrane 1 and have a second notch 32 that passes through said label 3 to define a second flap 33 that covers the window 2 and ? openable to form a second opening 22 which is passing through the label 3.

In one embodiment, the label 3 could completely or almost completely cover the external face 1b, for example to obtain a particularly resistant casing 100 in view of the strengthening determined by the stratification of the label 3 on the membrane 1, or to obtain a casing equipped of a window 2 which can also extend substantially across one side of the casing 100 itself.

To optimize the environmental impact of the 100 pu? instead, a window 2 of minimum size should be provided to allow sufficient visibility? of the inside of the casing 100 and, correspondingly, a label 3 for a surface of the membrane 1, peripheral to the window 2 which is? the minimum sufficient to guarantee a tight adhesion of the label 3 to the membrane 1 also depending on the adhesive 4 chosen to join them, so? to minimize the size of the label 3 and maximize recyclability? of the casing 100. In general, therefore, the membrane 1 can? present a portion free from the label 3.

Sticker 4, in detail, can extend across the first notch 11 and the second notch 32 to form an openable closure 5 which partially surrounds the window 2.

The first opening 21 and the second opening 22 can be overlapped to form an access which passes through the sheet 10 and which is can be opened and closed using the opening closure 5, so? to make it possible to obtain an openable and resealable 100 casing.

Sticker 4 can be a pressure sensitive adhesive or, in acronym, PSA. Preferably, sticker 4 can be a water-based or UV-curing acrylic adhesive or acrylic with organic solvent, or can it be? be a silicone-based adhesive for high temperatures (up to 250°C) depending on the contingent needs of implementing the invention.

Also form? the object of the present invention is a process for the production of a casing 100 which includes:

- a phase A, of joining a first layer 101, suitable for forming the membrane 1, with a second layer 102, suitable for forming the label 3, thus? to obtain a semi-finished product 300 given by the register union of the first layer 101 and the second layer 102;

- a phase B, of cutting the first layer 101 to create the window 2, for example by die-cutting;

- a separation phase C which involves cutting the semi-finished product 300 into pieces to form a sheet 10 from each piece.

Phase B can? also plan to cut the first layer 101 to form the first notch 11 and possibly also consider cutting the second layer 102 to form the second notch 32, for example by die-cutting, to create a sheet 10 suitable for creating an openable and resealable envelope 100.

This process can also include a cutting phase D, for example by die-cutting, to form a series of labels 3 carried by a ribbon-like support, for example as in figure 7, to couple them in register on the first layer 101 in order to obtain the sheet 10 having each label 3 applied to cover the opening 2, which can be made before or after joining label 3 to membrane 1.

In this text with the expression ?in register? do you mean a modality? of selective position of the two parts which are made to interfere in register.

Thus, for example, the application of a series of labels 3 in register on the first layer 101 determines that each label 3 is applied at a predefined distance from the previous and subsequent one and in a specific position of the layer 101 which corresponds to the position of creation, in register, of the opening 2.

The second layer 102 can? comprise a polymer film adhered to a ribbon-like support, where the polymer film is covered with an adhesive material suitable to define the adhesive 4.

In this case this process can include an inactivation phase E which involves a localized neutralization or inactivation of the capacity? adhesive adhesive material, which involves a treatment aimed at making said adhesive material non-adhesive in pre-established areas suitable for forming a series of operational portions 3a of the label 3, to form the window 2 and/or the detachment portion 31 in correspondence with these , so as to prevent that, once a wrapper 100 has been produced with the sheet 10, the products contained therein can adhere to the label 3 due to the action of the adhesive 4.

Phase E can? also be implemented by cutting, for example die-cutting, of the ribbon-like support so? to leave adherent to the second layer 102, and therefore to the label 3 obtained from it, a part of the ribbon-like support which forms a covering thread which corresponds to and defines the operational portion 3a of the label 3.

In this case the ribbon support is cut/punched in register to implement phase E.

In more detail, membrane 1 can? be configured to form a 100 wrapper for a food product and can? have a first notch 11 shaped so as to define a first flap 12, i.e. a flap, which can be opened to form a first opening 21 passing through the same membrane 1. The first notch 11 can define the edges or edges of the first flap 12. In other words, the first notch 11 can? form a first flap 12, i.e. a flap, movable between an opening position, in which it reveals or allows a passage through a first opening 21, and a closing position, in which it obstructs the first opening 21 and therefore prevents a passage through the latter. The first notch 11 can? therefore allow the formation of a passage through the membrane 1, for example, for the food product.

The first notch 11, in detail, passes through the membrane 1 between the external face 1b and the internal face 1a.

Label 3 can be fixed, i.e. joined or coupled, to the external face 1b or to the internal face 1a of the membrane 1. In this way, the label 3 can? define a reinforced portion of the membrane 1. By reinforced portion, in the context of this description, we mean a region or area of the membrane 1, which has greater mechanical resistance than the membrane 1 alone.

In particular, label 3 can cover even only partially the external face 1b, or the internal face 1a. Therefore, the outer face 1b, or the inner face 1a, can? include a portion free from label 3. In other words, the external face 1b, or the internal face 1a, can? include a portion free, i.e. not covered, from the label 3.

Furthermore, label 3 can have a second notch 32 that passes through it so as to define a second flap 33 that can be opened to form a second opening 23 passing through the same label 3.

Similarly, to what was said with reference to the membrane 1, the second notch 32 can be shaped so as to define the second flap 12, i.e. a flap, which can be opened to form the second opening 23. In other words, the second notch 32 can form a second flap 33, i.e. a flap, movable between an open position, in which it reveals or allows a passage through the second opening 23, and a closed position, in which it obstructs the second opening 23 and therefore prevents a passage through the latter. The second notch 32 can? therefore allow the formation of a passage through the membrane 1, for example, for the food product. The second notch 32 can? define the flaps or edges of the second flap 33.

The second draw 33 can? be fixed to the first flap 12 to form, together, an openable closure 5.

The first opening 21 and the second opening 23 can be overlapped and partially surround the window 2 which passes through the sheet 10 and which is can be opened and closed using the opening closure 5.

Sticker 4 can be provided on the operating flap 1c of the membrane 1 and/or on an adhesion portion 3a of the label 3 to hold them together, i.e. mutably or reciprocally, and allow separation and reunion of the openable closure 5.

In other words, sticker 4 can be placed between the operating flap 1c and the adhesion portion 3a and be permanently joined to one of these. In other words yet, sheet 10 can? include a sticker 4 that can? be placed on the operating flap 1c and/or on the adhesion portion 3a so as to promote adhesion between them, when the opening closure 5 ? in the closed position.

Said differently, sticker 4 can be such why? separation and repeated reunion of the operating flap 1c and the adhesion portion 3a is permitted, i.e. the adhesive 4 can? be configured to ensure that multiple units can be separated and brought together. the operating flap 1c and the adhesion portion 3a consecutive times.

The first notch 11 and the second notch 32 can have a substantially U-shaped or C-shaped shape. or ?V? in a plan view of sheet 10.

The terminals of the first notch 11 and/or the second notch 32 can form a curve or loop to prevent breakage or tearing of the membrane 1 and/or the label 3 in correspondence with these terminals following excessive opening traction exerted by the ?user on the opening closure 5.

According to a preferred aspect of the present invention, the first notch 11 and the second notch 32 can be made or obtained by means of a single cutting action of the membrane 1 and the label 3 mutually joined, i.e. mutually fixed.

In particular, according to this preferred aspect, the membrane 1 and the label 3 can be mutually joined before carrying out the single cutting operation in such a way that the cut passes through the first membrane 1 and the label 3 forming the first notch 11 and the second carving 32 staggered. It also follows in this way that the first flap 12 and the second flap 33 can also be overlapped.

In more detail, label 3 can be made of a polymeric material chosen from PP, PE, PLA, PET, NY. That is to say that it can? be made of a polymeric material chosen from the following: polypropylene (PP), polyethylene (PE), lactic acid or polylactic acid (PLA), polyethylene terephthalate (PET), nylon (NY).

Label 3, in particular, can be made of bio-plastic and can? be in a bio-based and/or biodegradable and/or compostable polymer, i.e. biodegradable through composting, for example in the product commercially known as Mater-bi?.

Alternatively, label 3 can be made of a laminate, i.e. a multi-layer material, made up of layers of different materials such as those mentioned above.

Can membrane 1? be made of cellulosic material or in general a highly biodegradable material.

In particular, membrane 1 can? be made of virgin paper (white, brown or other), recycled paper, ?barrier paper? o ?barrier? paper, i.e. paper covered with a layer of heat-sealing lacquer or other material configured to act as a barrier or waterproofing layer, monogloss paper, i.e. paper having a shiny surface, Kraft paper, i.e. paper based on raw coniferous cellulose, paper impregnated with oil or comprising an oily substance, commercially known as wax paper.

Furthermore, preferably, the weight of the membrane 1 can? be around 20-60 g/m<3>, even more? preferably, the weight? of approximately 30 g/m<3>.

The internal face 1a of the membrane 1 can? be covered with a heat-sealing lacquer designed to increase the seal of the sheet 10. In particular, by seal we mean a seal against fluids, such as air and humidity. Can heat-sealing hairspray be used? therefore forming a sealing barrier or waterproofing layer. In this way, ? Is it possible to increase durability? of the food product once packaged inside a wrapper 100 made with a sheet 10 having this characteristic. In addition, heat sealing hairspray can allow the edges of the membrane 1 to be joined, if made by heat welding, to form the casing 100.

Can membrane 1? extend predominantly along a longitudinal direction and label 3 can? form a ribbon that extends predominantly along the same longitudinal direction.

In other words, label 3 can have the shape of a ribbon, i.e. be ribbon-like, and develop mainly along a direction that coincides with the longitudinal direction of the sheet 10. In this way, it can be particularly easy to couple the label 3 to the membrane 1 to form the aforementioned sheet 10.

Can sheet 10? be flexible. That is to say that sheet 10 can? be folded back on itself? same.

The present invention also relates to a wrapper 100 which can be opened and closed to contain food products comprising the sheet 10.

To form the casing 100, in particular, the sheet 10 can be folded in such a way as to form a pocket that defines a compartment inside the casing 100, in which the edges of the sheet 10 can be joined together to close the pocket. For example, the edges of the sheet can be joined together via heat sealing.

In detail of the production process of a 100 casing, phase A can? be a union phase of the first layer 101, suitable for forming the membrane 1 and the second layer 102, suitable for forming the label 3. That is to say that the first layer 101 and the second layer 102 are respectively intended to form the membrane 1 and label 3.

From phase A can? a semi-finished product 300 can be produced given by the union of the two layers mentioned above, i.e. the first layer 101 and the second layer 102. Following phase A, it is possible to produce a semi-finished product 300. get what? the semi-finished product 300.

Phase B can? be a cutting step of the semi-finished product 300, to form the window 2.

Phase B can? also provide for a cut of the first layer 101 and the second layer 102 to respectively form the first notch 11 and the second notch 32. As part of phase B, therefore, the first layer 101 and the second layer 102 can be notched jointly. Can the cut? occur for example through die cutting.

Phase B can? be implemented before or after phase A.

Phase C? a separation phase that can? plan to cut the semi-finished product 300 into pieces to form a sheet 10. In other words, phase C can? plan to divide the semi-finished product into portions, i.e. pieces, so that from each piece it is possible to obtain a sheet 10 according to the present invention. Preferably, the first layer 101 and the second layer 102 can be ribbon-like. It follows that even the semi-finished product 300 can? be, in turn, ribbon-like.

Preferably, the semi-finished product 300 can? be stored in the form of reels. The first layer 101 can? have a width greater than the width of the second layer 102. According to this preferred aspect, the width of the second layer 102 can? cover a limited portion of the width of the first layer 101, when the two layers are joined in step A of the process described above. In other words, the second layer 102 covers the first layer 102 for a portion of said first width. It follows that only a part of the first layer 101 ? coupled to the second layer 102. Advantageously, part of the first layer 101 can? be, at the end of phase A, devoid of the second layer 102.

It is therefore clear how a sheet for producing a wrapper for food products or the like, a wrapper that includes it and a production process of the latter according to the present invention allows the intended task and objects to be achieved.

What was found like this? conceived? susceptible to numerous modifications and variations, all falling within the scope of protection of the attached claims.

Furthermore, all details may be replaced by other technically equivalent elements.

Where the operational characteristics and techniques mentioned are followed by reference marks or numbers, such reference marks or numbers have been affixed with the sole purpose of increasing intelligibility. of the description and claims themselves and, consequently, they do not constitute in any way a limitation on the interpretation of each element identified, purely by way of example, by such signs or reference numbers.

Claims (10)

1. Sheet (10) for forming a wall of an envelope (100) for containing food products, wherein said sheet (10) comprises: - a membrane (1) made of cellulose material having a heat-sealable internal face (1a) and an external face (1b); where said membrane (1) ? configured to create a wall of a casing (100) for a food product following mutual heat sealing of portions of said membrane (1); said membrane (1) having an edge configured to define a discontinuity? in said wall, following a production of said casing (100), where said discontinuity? ? designed to allow viewing inside said casing (100); - a label (3), fixed to said membrane (1) by means of an adhesive and overlapping said edge in such a way that, following production of said casing (100), said discontinuity? ? covered by an operational portion (3a) of said label (3) where said operational portion (3a) is transparent to retain the products housed in it inside said casing (100) and at the same time allow visibility. inside said casing (100); where the operational portion (3a) of said label (3) is? without said sticker (4) or said sticker (4) ? inactivated in said operational portion (3a) or covered by a covering film. 2. Sheet (10) according to claim 1, where said edge develops according to a closed trajectory shaped and sized in such a way as to define a window (2) in said membrane (1) suitable for allowing visibility. of the inside of said casing (100) following the production of the latter. 3. Sheet (10) according to one of the previous claims where said label (3) has a detachment portion (31) which is without said sticker (4) or where said sticker (4)? inactivated and extends from a perimeter of said label (3) which creates an invitation tab graspable by a user and easily separable from said membrane (1) and to lift it to force a separation of said label (3) from said membrane ( 1) to send them to different recycling chains. 4. Sheet (10) according to claim 2 or 3 where - said membrane (1) has a first notch (11) which is shaped to define a first flap (12) that can be opened to form a first opening (21) which is passing through said membrane (1); said window (2) being provided on said first flap - said label (3) ? fixed to the external face (1b) of said membrane (1) and has a second notch (32) that passes through said label (3) to define a second flap (33) that covers said window (2) and is? openable to form a second opening (22) which is passing through said label (3); where said external face (1b) has a portion free from said label (3); said adhesive (4) extending across said first notch (11) and said second notch (32) to form an openable closure (5) which includes said window (2) and where said first opening (21) and said second opening (22) are overlapped and form an access that passes through said sheet (10) and which is? can be opened and closed using said opening closure (5); 5. Sheet (10) according to one of the previous claims where said adhesive (4) is? a PSA pressure sensitive adhesive. 6. Process for the production of a casing (100) according to the previous claim where said process comprises: - a phase A, of joining a first layer (101), suitable for forming said membrane (1), with a second layer (102), suitable for forming said label (3); said phase A forming a semi-finished product (300) given by the register union of said first layer (101) and second layer (102); - a phase B, of cutting said first layer (101) to create said window (2), for example by die-cutting; - a separation phase C which involves cutting said semi-finished product (300) into pieces to form a sheet (10) from each piece according to one of claims 1 to 5. 7. Process according to claim 6 where said phase B involves cutting said first layer (101) and said second layer (102) to form said first notch (11) and said second notch (32), for example by die-cutting, to create a sheet (10) according to one of claims 4 and 5. 8. Process according to one of claims 6 and 7 where it includes a cutting phase D, for example by die-cutting, to form a series of said label (3) carried by a ribbon-like support to couple them in register on said first layer (101) to form said sheet (10). 9. Process according to one of claims 6-8 wherein said second layer comprises a polymeric film adhered to a ribbon-like support, wherein said polymeric film is? covered with an adhesive material (4) suitable to define said adhesive (4). 10. Process according to claim 9 which includes a phase E of localized inactivation of said adhesive material (4) which optionally includes: - a treatment suitable for making said adhesive material (4) non-adhesive (4) in pre-established areas suitable for forming a series of the operational portion (3a) of said label (3), to form said window (2); - a cut, preferably by register die-cutting of said ribbon-like support to obtain from the latter a covering film of each label 3 to define each operational portion of the latter.