IT202000016132A1 - ANTI-PACKING ADHESIVE VALVE, SHEET INCLUDING IT, AND FOOD CONTAINER FORMED WITH THIS SHEET, AND A PROCEDURE FOR MANUFACTURING THEM - Google Patents

Description

ANTI-PACKING ADHESIVE VALVE, SHEET WHICH INCLUDES IT AND FOOD CONTAINER FORMED WITH THIS SHEET, AS WELL AS

A PROCEDURE FOR MANUFACTURING THEM

TECHNICAL FIELD

The present description relates to an anti-packing adhesive valve, a sheet comprising it and a food container formed with this sheet, as well as a process for making them.

This adhesive valve, and flexible, can? be applied on incisions or openings obtained on airtight containers, for example for coffee? and similar packaging of shelf products for which the possibility is required? to discharge gas from inside -always maintaining the seal with respect to the gas inlet- to avoid the visual effect of a swollen package.

In particular, the adhesive valve in question allows the discharge of gas from inside a container which incorporates it even if it is compressed against a further container or against another object, for example when a stack of containers is formed on which valves insist other containers of the pile.

The adhesive valve in question particularly allows to obtain an anti-packing effect thanks to the weak molecular interactions between the surfaces which delimit a discharge duct, moreover the adhesive valve in question can? be preferably of the multilaminate type in polymeric material with control of the ?blocking? i.e. the ability of the polymeric film to adhere to another polymeric layer.

The present teaching also relates to a sheet and a container for food comprising said adhesive valve, as well as a method for manufacturing the adhesive valve and/or sheet comprising it.

STATE OF THE ART

Nowadays, the adhesive valves described for example in EP2271000210002, WO2011000/1110011000A1, WO/2019/07710003200, in the name of the same applicant, are known and highly appreciated.

? further known is a traditional valve, described in US200200/007200010008, which comprises an adhesive label having a plurality of? of holes and a flexible membrane which covers the holes to keep them closed in a rest condition and which adheres to the flexible label.

This adhesive valve? configured to be associated with a sheet adapted to form a food container.

In particular, the flexible membrane has a vent hole which is superimposed when the adhesive valve is fixed to the sheet, to a plurality? of holes that the sheet has, to discharge gas from inside the container.

The hole in the membrane? misaligned to the holes of the flexible label in such a way that, if gas presses from the inside of the sheet through the holes of the latter and the hole in the membrane, it tends to lift the flexible label insinuating itself between it and the flexible membrane, opening what? a drain channel to and through the holes in the flexible label.

One problem with such a traditional sticky valve? that if an object is superimposed on the container where this valve is provided which weighs on the adhesive valve itself, this is kept closed and the gas vent ? what? prevented or hindered.

From this inconvenience can? for example to derive the much unwelcome swelling effect of food containers in case of stacking them with the valves compressed.

SUMMARY

The problem at the basis of this teaching? therefore that making it possible to discharge gas from valved food containers, even when they are stacked or stacked with the valves capped and possibly compressed.

Within the scope of this aim, an object of the present teaching is to provide an adhesive valve which allows the venting of gas more easily. faster than traditional adhesive valves when the valve is compressed or a product is superimposed on it.

Another task of this teaching? that of proposing an adhesive valve that is resistant while remaining sensitive to even small pressures? for example of the order of 4 mbar and more.

Another task of this teaching? that of making available a simple and economically implemented adhesive valve while allowing for the creation of adhesive valves that allow gas to be discharged at low pressures and more? faster than traditional valves.

Yet another task of this teaching? that of proposing a semi-finished product for forming a food container which incorporates said adhesive valve, this food container and a process for making the adhesive valve or semi-finished product, which achieve the above mentioned tasks.

This task, as well as these and other objects which will become apparent hereinafter are achieved by an adhesive valve, a semi-finished product, a container and a process according to the respective independent claims attached.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and characteristics of the adhesive valve, the semi-finished product, the container and the method according to the present description will become apparent to those skilled in the art from the following detailed and non-limiting description of their embodiments with reference to the accompanying drawings in which:

- Figure 1 illustrates in schematic form a portion of a semi-finished product according to the present teaching in which some parts have been partially removed to facilitate visibility? others, in perspective view, where the dimensions of the parts shown have been exaggerated to increase intelligibility;

- figures 2a to 2d show in schematic form variants of an adhesive label of an adhesive valve according to the present teaching, seen in plan view from above; - figures 3a to 3f schematically show first variants of a third zone C affected by a second adhesive according to the present teaching, seen in plan from above;

- figures 4a to 4g show in schematic form second variants of a third zone C affected by a second adhesive according to the present teaching, plan view from above superimposed on an exemplifying variant of an adhesive label of an adhesive valve according to the present teaching ;

- figures 5a to 5e show in schematic form variants of a non-stick portion E superimposed on exemplary variants of an adhesive label of an adhesive valve according to the present teaching;

- figure 6 shows in schematic form a cross section of an adhesive valve according to the present teaching, where the proportions are not respected to increase intelligibility;

- figure 7 shows in schematic form a cross section of an adhesive label of an adhesive valve according to the present teaching where the proportions are not respected to increase the intelligibility?

figure 8 shows in schematic form a protective membrane of an adhesive valve according to the present teaching in plan view from below;

- figures 9 and 10 show in schematic form parts of a plant for the production of an adhesive valve, a semi-finished product and/or a tank according to the present teaching.

DETAILED DESCRIPTION

With particular reference to the cited figures, an adhesive valve 100 according to the present teaching comprises:

- an adhesive label 101 having an upper surface 101a and a lower surface 101b, where at least one first incision 102 connects the two upper surfaces 101a and lower 101b to form a passage for a gas; at least a portion of the lower surface 101b can? be provided with a first adhesive 101c;

- a covering membrane 103 applied to the upper surface 101a of the adhesive label 101.

The adhesive valve 100 has, between the adhesive label 101 and the covering membrane 103:

- a first area A, in which the adhesive label 101 and the covering membrane 103 are not mutually joined by adhesive and which, seeing the adhesive valve 100 in plan view, overlaps the first incision 102 at least partially;

- a second area B, in which the adhesive label 101 and the covering membrane 103 are not mutually joined by adhesive, which? adjacent to the first zone A or integral with the latter to define a discharge channel, for a gas, which extends from the at least one first incision 102 towards a perimetric edge of the covering membrane 103;

- a third area C, in which a second adhesive 105 fixes the covering membrane 103 to the adhesive label 101.

The first engraving 102 pu? consist of a single hole passing through the adhesive label 101, for example as visible in figures 1 and 2a, or in a plurality? of micro-holes passing through the adhesive label 101 which can be made continuously, for example as in figures 2b and 2d, or in register, for example as in figure 2c.

The at least one first incision 102 possibly pu? include one or consist of a linear notch or a plurality? of possibly curved linear notches and possibly combined with one or more? through holes, such as for example the linear notches indicated with references 102a in figure 2d.

The adhesive label 101 and the covering membrane 103 develop mainly in a first and second direction having a thickness in a third direction, perpendicular to the first two.

They are stacked in the third direction to overlap to define therebetween a discharge channel which extends in a direction substantially perpendicular to this third direction.

For simplicity? constructively, they can have a substantially superimposed perimeter, seen in plan view, ie along said third direction.

Or, the cover membrane 103 can? extend beyond the perimeter of the adhesive label 101 to be fixed, by means of the second adhesive 105, to a sheet 200 to which the adhesive label 101 can be fixed, such as by way of example and not limitation ? visible in figures 5a, 5b and 5c where the perimeter of the covering membrane 103 surrounds the perimeter of the adhesive label 101.

Clearly, for example, to ensure better deformability? of the adhesive valve 100, pu? the contrary be foreseen, ie that the adhesive label 101 can? extend beyond the perimeter of the covering membrane 103.

In general, it is therefore understood how an adhesive valve 100 according to the present teaching allows a gas to be discharged, as for example shown in figure 1 by means of arrows, from a container which incorporates the adhesive valve 100, even when this is compressed, i.e. particularly in case of stacking of containers or when the container ? resting on its face which includes the adhesive valve 100.

In other words, even if a foreign object presses on the covering membrane 103, since? the exhaust channel defined by the first and second zones A and B extends parallel to it, the gas will be able to? come out laterally from the adhesive valve 100, as visible in figure 1 where the gas path ? stylized with arrows.

In fact, the channel formed by the second area B and possibly also by area A actually extends parallel to the wall of the container which incorporates the adhesive valve 100, making it more easy passage of gas through it compared to traditional solutions which provide for a gas route that ? overall perpendicular to the wall of the container since the openings on traditional valves define a passage which allows it to pass only in that direction.

With particular reference to figures 3a to 3f, the shape and arrangement of the first, second and third zones A, B and C may be chosen according to the contingent needs of implementation of this teaching.

For example, the drainage channel formed by the first and second zones A and B will be able be more large, as in figure 3a or 3b or more? narrower, as in figures 3c, 3d, 3e, 4d or 4e, with respect to the width of the first incision 102, when this forms a hole, for example central to the adhesive label 101.

What? for example, could respectively have a higher speed? vent or a lower speed? vent, respectively.

This drainage channel could also have a radial shape, as for example in figure 3f, 4a, 4b, 4f, which could? then have a plurality? of parts that diverge for example from the first zone A.

In this way, any blockage of one of the parts, for example due to fouling or damage to the adhesive valve 100, could be compensated for by the presence of the others.

The size and number of these parts can be chosen to modulate the pressure of the gas discharge and the speed? of discharge of the same, in way of s? known.

Furthermore, the drainage channel will be able to develop according to a trajectory presenting curves or labyrinthine, as for example in figure 4c or 4g in order to allow to regulate in a refined way both the opening pressure and the speed? by modulating the extension and width of the discharge channel along this trajectory.

To facilitate the discharge of gas, the adhesive valve 100 can? comprise a separator element 104 placed between the adhesive label 101 and the covering membrane 103 in the first area A and/or in the second area B and able to distance the adhesive label 101 from the covering membrane 103 to allow the separation of the latter even when they are pushed one on top of the other, to allow a passage of a fluid between them.

The separator element 104 can? include a paint and/or an insert that can? be made of polymeric material.

The separator element 104 can? have a thickness between 1 and 300 microns to correspondingly separate the adhesive label 101 from the cover membrane 103.

The separator element 104 can? comprehend:

- at least one elongated section which extends at least predominantly in one development direction in which the second zone B extends, as for example shown in figures 1 and 2a and/or

- at least one curved section which extends into the first area A and/or into the second area B, for example as in figures 2b and 2c.

The adhesive label 101 and/or the covering membrane 103 are configured to adhere mutually by electrostatic action to each other in at least the second area B, so that the channel defined by the second area B is sealed when not ? crossed by a fluid coming from the first incision 102 of the adhesive label 101.

Depending on the contingent needs of implementation of the present teaching, the adhesive label 101 and/or the covering membrane 103 can have at least one non-stick portion E configured in such a way as to prevent or oppose the mutual adhesion of the adhesive label 101 and the covering membrane 103 by electrostatic action or by the action of Van der Waals forces in the first zone A and/or in the second zone B.

For example, the non-stick portion E pu? include a lacquer that can? be silica-based and which covers a part of the upper surface 101a of the adhesive label 101 in the first area A and/or in the second area B and/or a part of the face of the covering membrane 103 which faces the upper surface 101a.

The non-stick portion E pu? have a thickness approximately between 0.1 micron and 20 micron where it is implemented by means of, for example, a lacquer.

With particular reference to figures 5a to 5e, the shape and extension and number of the non-stick portion E may be? be chosen to modulate the gas discharge pressure and at the same time to ensure an optimal seal of the adhesive valve 100 with respect to an undesired gas infiltration from the outside through the discharge channel.

In general, the presence of a non-stick portion And more? extended and/or more? close to the perimeter of the adhesive valve 100, seen in plan view, as for example in figure 5a and 5b, can determining a lower discharge pressure with respect to configurations which provide for a smaller extension of the non-stick portion E or of the non-stick portions E or their greater distance from the perimeter of the adhesive valve 100.

The adhesive label 101 and/or the covering membrane 103 can? include a polymeric material with additives to obtain the effect commonly known as ?antiblocking?.

This effect can be achieved by increasing the surface roughness of one surface that comes into contact with another to prevent mutual adhesion.

In particular, this increase in roughness pu? be obtained by adding to a polymeric material a granular additive so? that the latter being dispersed in the matrix of polymeric material itself and projecting from the surface of the same generates an invitation effect for the separation of the surface itself from another surface to which it would tend to act, how? the case of the tendency of the adhesive label 101 and/or the covering membrane 103 to adhere to each other.

This polymeric material can also comprise or consist of branched monomers for the alteration and control of blocking and weak molecular interactions to ensure a lower presence of residual monomers which could migrate to the surface and which appear to be responsible for the actual blocking effect.

In Pe llld for example, you can? limit the use of EVA.

Furthermore, an excessive use of slips in the composition of the polymeric material, migrating to the surface, can compromise the surface corona treatment, limiting its affinity? to the coatings and, therefore ? preferably to be avoided or limited.

It can therefore be understood that a balance in the recipe relating to the composition of said polymeric material, as discussed in the present document, is therefore fundamental for the purposes of a product stable over time in view of the specific implementation.

The antiblocking effect obtained by adopting at least one surface layer, of the adhesive label 101 and/or of the covering membrane 103, made of this polymeric material with antiblocking additive, makes it possible to reduce the force necessary to separate them and, therefore, reduces the pressure of a gas, which insinuated between them coming from a first incision 102.

In other words ? it is possible to obtain the venting of a gas even at very low pressure, i.e. from about 4 mbar of relative pressure.

To this end, the adhesive label 101 and/or the covering membrane 103 can consist of a polymeric material with an antiblocking additive or can comprise a surface layer made therefrom.

The choice of the polymeric material and of the additive depends on the contingent needs of implementation of the present teaching.

In general, the polymeric material can? consist of LDPE, LLDPE, PP, PET OR PA, in which case the concentration of the additive can? be chosen indicatively between 0.10% and 0.20% by weight and the additive can? consist of synthetic silica with a surface area indicatively between 50 and 1000 m2/gr and with a particle size approximately between 2 microns and 10 microns.

Although presenting a minor antiblocking effect, pu? be used as an additive also the natural silica that pu? have a surface area indicatively between 2 and 70 m2/gr and with a grain size approximately between 40 microns and 100 microns, where as a polymeric material it can? LDPE or LLDPE with an additive concentration ranging for example from 0.25% to 0.45% by weight may be chosen.

As an additive can? Also selected are calcium carbonate, kaolin, clay and/or talc in a concentration of about 0.35% to 0.65% by weight in a polymeric material which can be be chosen from LDPE and LLDPE.

Also zeolites with a concentration indicatively between 0.20% and 0.40% by weight can be selected as additives for example for a polymeric material selected from LLDPE, PVC, PET and PA.

In addition, organic antiblocking additives such as zinc stearate, silicone oils or rubbers, polytetrafluoroethylene PTFE, glyceryl monostereate GMS, eurucamide, stearamide, stearyl eurucamide, ethyl bis stearamide EBS can also be employed.

In general, in accordance with the present teaching, silicas are the preferable additives.

The choice of using natural silicas or synthetic silicas depends on the contingent needs of implementation of the present teaching.

In general, natural silicas have the advantage of low cost, high concentration masterbatches, lower absorption of other additives compared to synthetic silicas, however they present health risks during the masterbatches production phase, presence of impurities and lower antiblocking efficacy compared to silicas synthetic.

Synthetic silicas, on the other hand, are preferable due to the high surface area, the possibility of of insertion of reactive groups, substantial absence of impurities, absence of health risks during the production phase of the masterbatches, however today they present a higher cost, a maximum concentration in the masterbatches of 20% and a greater absorption of other additives compared to silicas natural.

The first engraving 102 pu? form a plurality of holes 102a passing through the adhesive label 101 which can be obtained for example by die-cutting in register or continuously on a strip of material from which to obtain a plurality? of adhesive labels 101.

The bottom surface 101b of the adhesive label 101 can have a non-adhesive working portion 106.

At least some of said holes 102a extend from the operating portion 106 through the adhesive label 101.

The operating portion 106 can? be devoid of the first adhesive 101c or can? have a film 106a covering the first adhesive 101c, as exemplified in figure 7.

This film can be formed by a film in polymeric material and pu? be obtained by die-cutting from a liner which, during the production process of the adhesive valve 100, originally completely covered the first adhesive 101c and which after die-cutting of the film is removed from the first adhesive 101c except in the operative portion 106 so to leave the film that covers it.

Alternatively, the film pu? be formed by a lacquer that ? deposited on the first adhesive 101c at the portion of the operating portion 106.

For example, the said lacquer can? be a material known in the industry as a ?glue killer?.

The upper surface 101a of the adhesive label 101 can include at least a first portion, that ? facing a second portion of the covering membrane 103 so as to form the first area A and/or the second area B.

Depending on the contingent implementation needs of the present invention, for example to optimize the production process, optionally:

- the first portion and/or the second portion are optionally either without adhesive or covered with an adhesive that is? coated with a non-stick layer comprising a lacquer and/or a polymeric material film;

- one between the first portion and the second portion? covered with a further adhesive, the other being covered with a non-stick material, for example with a silicone coating able to counteract an action of adhesion of the further adhesive on it.

To prevent possible damage to the covering membrane 103 and/or to the adhesive label 101, the adhesive valve 100 can? comprise a protective membrane 107 fixed on the covering membrane 103 and/or on the adhesive label 101 to cover them so as to protect them from interactions with objects foreign to the adhesive valve 100.

The adhesive valve 100 pu? also comprise a third adhesive 108 which fixes the protective membrane 107 to the cover membrane 103.

Between the protective membrane 107 and the covering membrane 103 can? there should be at least one adhesive-free area D positioned and/or shaped to limit a separation stress of the covering membrane 103 from the adhesive label 101, which would be generated by a retention action by the protective membrane 107 on the covering membrane 103 following a bending of the adhesive valve 100, for example as illustrated in figure 8.

form also? object of the present teaching is a semi-finished product 1000 from which to obtain a food container.

The semi-finished product 1000 includes:

- a sheet 200 for forming a food container which has two surfaces and has at least one second incision 201 connecting the two surfaces;

- an adhesive valve 100 which covers the second incision 201 in such a way that at least one first incision 102 of the adhesive label 101 is superimposed on at least one second incision 201 of the sheet 200 to define a path for a possible venting of gas from a container that is format with sheet 200.

form also? object of the present teaching is a food container which comprises a semi-finished product 1000 and which has an internal compartment for housing food on which ? the second incision 201 of the sheet 200 faces to be crossed by a fluid and in particular by a gas contained in the internal compartment and having a higher pressure than the pressure outside the food container.

In general, the adhesive label 101 and/or the covering membrane 103 can be obtained from a film of a plastic material suitable for coming into contact with food, for example belonging to the group consisting of polypropylene (for example with a thickness between 35 and 300 microns and preferably 90 microns), polyester (for example with a thickness of between 25 and 45 microns) or plastic materials with equivalent characteristics, such as PET or PE.

The 101 adhesive label can? be formed by a laminate with pi? layers, in particular comprising plastic material, polyethylene, cellulose material, aluminum and/or a polyamide film, for example with a thickness ranging for example from 10 to 20 microns, or a PE-Evoh-PE laminate. Furthermore, the 101 adhesive label can be formed from recyclable materials such as polylactic acid and / or pu? be a multilayer laminate, comprising an inner layer, which defines the lower surface 101b, made for example of a material selected from those indicated above, and an outer layer, which defines the upper surface 101a, preferably made of a barrier material which increases the ?impermeability? of the adhesive valve 100.

For example, the 101 adhesive label can include a layer of Polyethylene terephthalate, PET, about 30 microns thick with a layer of polypropylene, PP, about 90 microns thick, but which can? even reach 300 microns according to the contingent needs of implementation of the present teaching, with a further layer of PE-evoh, or PET or PP or PA, of about 40 microns.

The 101 adhesive label can? include a combination of polypropylene, which can? have a thickness of about 30 microns, and PE-evoh, which can? have a thickness of about 40 microns.

The lower surface of the covering membrane 103 can be covered, in the first area A, with a material compatible with food use, which is capable of making it non-adherent or limitedly adherent, in particular silicone or another type of coating per se? traditional but still dry.

The first 101c sticker can? be a pressure-activated adhesive or PSA (Pressure Sensitive Adhesive), in particular pu? be a water-based acrylic adhesive or UV curing or acrylic with organic solvent, or can? be a silicone-based adhesive for high temperatures (up to 250°C) according to the contingent needs of implementation of the invention.

In a preferred embodiment, although not exclusive to the present teaching, the adhesive label 101 and/or the covering membrane 103 can be made of a material which has a higher elastic modulus than linear low density polyethylene, LLDPE, used for similar applications, and allow a? electrostatic attraction to the substrate on which it rests not strong, ie that does not create intermolecular attractions of strong order.

For example, the adhesive label 101 and/or the covering membrane 103 can preferably be made of a polyethylene, PE, free from almost all additives, except nanometric silica, which has an attractive force sufficient to close the discharge channel of the gas, to avoid infiltrations from? external, but at the same time is weak enough to favor a release of pressurized gas from inside the container which includes the adhesive valve 100.

Further characteristics of the materials and of the manufacturing process of the adhesive label 101 can be those described in the European patent 2275252 and in the publication WO2015/111015A1.

The 101 adhesive label can? have a substantially polygonal and/or curvilinear shape, for example substantially square, or - for example - circular or triangular, with rounded corners and optionally provided with anti-tampering notches, not shown. The adhesive label 101, seen in plan view, can be? extend over an area x mm wide and y mm long, with x and y between 20 and 40, in particular between 25 and 36 and preferably x = y = 25.

The covering membrane 103 preferably has an identical shape to that of the adhesive label 101, seen in plan view or it can extend beyond the perimeter of the adhesive label in at least one direction and, depending on the contingent actuation requirements, for example in at least two opposing divergent directions to substantially straddle the adhesive label 101 so as to help hold it to the sheet 200.

The protective membrane 107 can? have an identical shape to that of the covering membrane 103, seen in plan view or extend beyond the perimeter of the latter in at least one direction.

In a rest condition of the adhesive valve 100, the first incision 102 is closed as a result of mutual adhesion of the adhesive label 101 with the covering membrane 103, for example by electrostatic action or as a result of Van der Waals interactions, as more described above.

The? extension, as well as? the shape and the number? of the non-stick portion E ? chosen on the basis of the contingent needs of implementation of this teaching.

In particular, the non-stick portion E will be able to have cusp-shaped parts directed towards the outer perimeter of the adhesive valve 100 to form invitations for a gas under pressure to insinuate itself between the covering membrane 103 and the adhesive label 101.

However, this cusp shape, on the one hand facilitates the passage of gas from the first zone A, through the second zone B towards the perimeter of the adhesive valve 100, seen in plan view, on the other hand it prevents the access of air in the opposite direction, i.e. from the outside of the adhesive valve 100 through the channel defined by the second zone B towards the first zone A.

How more? above anticipated, the adhesive label 101 pu? also have tamper-evident notches which, for example, can be arranged in mutually opposite positions and can be shaped so as to extend along a curved and, in particular, circular or elliptical trajectory to define, with their ends, a preferential trigger portion of fracture of the adhesive label 101, if this is removed from a sheet on which it has been applied.

Sheet 200 can? be able to close or form a food container, pu? be made of plastic and used to make a bag or be heat sealed to the edges of a rigid tray, can? have at least one second incision 201, which connects the two surfaces of the sheet, covered by the adhesive valve 100 to seal the inside of the container while allowing a discharge of gas from the latter.

The second engraving 201 in the sheet can? be rectilinear, curvilinear or closed, so that the portion of the sheet surrounded by the second incision 201 can be removed and form an opening, for example substantially circular. The second engraving 201 in the sheet can? also be arched, so as to form a tongue-shaped portion that you can? flex towards the adhesive valve or away from it. At least one layer of adhesive, in particular PSA adhesive, for example of a rectangular shape, can? be arranged on a portion of the sheet around the second incision 201 to promote adhesion to the sheet of the adhesive label 101 and/or of at least one edge of the covering membrane 103 and/or of at least one edge of the protective membrane 107 which extends beyond the perimeter of the adhesive label 101 and/or of the covering membrane 103 respectively.

The protective membrane 107 can? be in a plastic material such as PE, PEHD, PP, MDO, polyesters and

In relation to the producibility? of the adhesive valve 100, form also? object of the present teaching a tank 2000 for adhesive valve applicator 100 which comprises:

- a support membrane 2001 having an operating face;

- a plurality? of adhesive valves 100 applied to the operative face and removably fixed thereto.

The support membrane 2001 pu? consist, for example, in a tape that develops mainly in a longitudinal development direction along which are aligned a plurality? of the adhesive valves 100 to form at least one row.

The adhesive valves 100 can be fixed to the operative face by means of the first adhesive 101c and, during a production process of a food container, be detached from the support 2001 to be applied on a sheet 200 to form and cover the at least one second incision 201 of the latter.

form also? object of the present teaching is a process for manufacturing an adhesive valve 100 which comprises the following steps:

- step A of applying a first adhesive 101c to a lower surface 101b of a first layer;

- step B of etching the first layer to make said at least one first etching 102;

- step C of fixing a second layer to an upper surface of the first layer by means of a second adhesive 105 so as to form the first zone A, the second zone B and the third zone C of the adhesive valves 100;

- step D of cutting the first layer and/or the second layer to respectively obtain the adhesive label 101 and/or the covering membrane 103.

Furthermore, the procedure can comprising a step E of applying the separator element 104 between said first layer and said second layer, in correspondence with each first zone A and/or second zone B.

This procedure can also comprise a step F of applying the first layer to a support membrane 2001 which ? cuttable to form the aforementioned 2000, for example a ribbon.

Furthermore, the procedure can comprising a step G of attaching a third layer to an upper face of the second layer, to form protective membranes 107.

Also can a step H of cutting the third layer, for example by register punching, to obtain the protective membrane 107 of the adhesive valve 100 so that it covers the covering membrane 103 should be provided.

In one embodiment of the present process, the protective membrane 107, covering membrane 103 and the adhesive label can be obtained simultaneously by cutting, for example by die-cutting in register, of the respective first, second and third layers.

The first layer, the second layer and the possible third layer can be in the form of strips worked continuously along one processing direction.

In this case, as anticipated, phase D ? preferably carried out by continuous or register die-cutting along said processing direction.

The manufacturing process of the adhesive valve 100 can therefore provide that a tape 11 preferably wound in a reel 12 is pulled, for example in the direction of the arrows illustrated in and, by one or more? first auxiliary rollers 13. The tape 11 can? comprise a first layer 14 of material suitable for forming the adhesive labels 101, which can be joined by at least one layer of a second adhesive 105 to a support 3 made of material suitable for forming the covering membranes 103 mentioned above.

The first layer 14, the support 3 and/or the layer of second adhesive 105, comprised between them, are preferably continuous and uniform and, for example , formed into tapes.

A first of the auxiliary rollers 13 can? separate the first layer 14 from the support 3, which can be pulled separately by other auxiliary rollers 13, for example as shown in figure 9.

The first layer 14 of the tape 11 can be provided with a series of non-stick portions E which can be placed at regular distances one after the other on the adhesive surface of the first layer 14, which, with reference to the example in figure 9 ? facing upwards, so as to form the first zones A and the second zones B.

The series of non-stick portions E pu? be disposed by an applicator 16 who, for example, applies and dries a non-stick substance on the non-stick portions E, for example a lacquer which can? be silica based.

In an alternative not shown in the attached figures, the first layer 14 and the support 3 can be pulled from respective reels and the second adhesive layer 105 can be drawn from the respective reels. be deposited on one or the other in continuous register leaving areas free from the second adhesive 105 so as to form the first areas A and the second areas B.

In this variant, in a similar way to what has been described above, the first layer 14 of the tape 11 or the support 3 can be provided with a series of non-stick portions E which can be placed at regular distances one after the other by an applicator 16 which, for example, applies and dries a non-stick substance on the non-stick portions E, for example a lacquer which can? be silica based.

The first layer 14 can? be provided with a series of incisions 1b placed at the same regular distances between the non-stick portions E, by a perforator 20, for example by a laser perforator, possibly with the aid of a sensor 21 adapted to detect the position of a non-stick portion E on the first layer 14, so that the non-stick portion E is crossed by the incision 1b, looking at it in plan view.

The incisions 1b in the first layer 14 can also be made before making the non-stick portions E.

Tape 11 holder 3 can? be joined to the first layer 14 by one or more? second auxiliary rollers 23, with any non-stick portions E arranged between the first layer 14 and the support 3.

The first layer 14 of the tape 11 can then be punched by a first mechanical punching machine, in particular by a roller punching machine 24, to form in the first layer 14 a series of adhesive labels 101 where the punching cut can surround the non-stick portions E, distancing themselves from them or intercepting them too.

In particular, the material of the first layer 14 in excess of the series of adhesive labels 101 (not shown in the figure) can be excised. Tape 11 holder 3 can? be punched by a second mechanical punching machine, in particular a roller punching machine 25, to form from the support 3 a series of covering membranes 103 which are each covered by an adhesive label 101 with any non-stick portion E interposed between them.

In this way ? It is possible to obtain the tank 2000, where the tape 11, possibly cut lengthwise, acts as a support for a series of adhesive valves 100 forming the support membrane 2001.

What? the tape 11, with the adhesive valves 100 pu? be wound onto a reel 26. With reference to Figure 10, it can be seen that in a first operating step of the process for manufacturing a sheet 200 to form containers, a base membrane 6, preferably wound onto a reel 31, is pulled, to example from one or more? first auxiliary rollers 32, after which? a punching machine 33 forms the second incisions 201 in the base membrane 6.

Optionally, an applicator 34 applies layers of adhesive on the base membrane 6 near the second incisions 201, after which a labeling machine 34 applies adhesive valves 100, for example by taking them from the support membrane 2001, onto the second incisions 201 of the base membrane 6, with the lower surface of the adhesive label 101 in contact with the sheet 200 in the manner described above. Sheet 200 with one or more? adhesive valves 100 to form the semi-finished product 1000, possibly pulled by further auxiliary rollers 32, ? wrapped on a reel that can? form the tank 2000, as for example in figure 10.

In a later stage, not shown in the figures, the sheet can be taken from reel 36 and cut to obtain a plurality? of lengths which comprise at least one adhesive valve 100 and can be used to make containers for food use, for example as a cover for a container in which the length of sheet is? joined to the edge of other lengths of sheet to form the container, in particular by adhesive or heat-sealing.

It is therefore understood how an adhesive valve, a semi-finished product comprising it, a container comprising it and a method for manufacturing it allow to achieve the intended aim and objects.

In particular, a container which integrates an adhesive valve according to the present invention allows to avoid the swelling effect like a ?doll? That ? significantly detrimental to the presentation of the product.

The found what? conceived ? susceptible to numerous modifications and variations, all falling within the scope of protection of the attached claims.

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

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

In particular, this teaching ? to be understood as comprising further embodiments which may include the technical characteristics of one of the following claims with the addition of one or more technical characteristics described in the previous text or illustrated in the drawings, taken individually or in any reciprocal combination.

Claims (22)

1. Adhesive Valve (100) comprising: - an adhesive label (101) having an upper surface (101a) and a lower surface (101b), where at least one first incision (102) connects the two upper and lower surfaces to form a passage for a fluid; - a covering membrane (103) applied on the upper surface (101a) of the adhesive label (101); said adhesive valve (100) has, between the adhesive label (101) and the covering membrane (103): - a first area (A), in which the adhesive label (101) and the covering membrane (103) are not mutually joined by adhesive and which, seeing the adhesive valve (100) in plan view, overlaps the first incision ( 102); - a second zone (B), in which the adhesive label (101) and the covering membrane (103) are not joined together by adhesive, which is? adjacent to the first zone (A) or integral with the latter to define a discharge channel, for a fluid, which extends from the at least one first incision (102) towards a perimetric edge of the covering membrane (103); - a third zone (C), in which a second adhesive (105) fixes the covering membrane (103) to the adhesive label (101). 2. Adhesive valve (100) according to the preceding claim which comprises a separator element (104) placed between the adhesive label (101) and the covering membrane (103) in said first zone (A) and/or in said second zone (B) and able to distance the adhesive label (101) from the covering membrane (103) to allow the separation of the latter even when they are pushed one against the other, to allow a passage of a fluid between them. 3. Adhesive valve (100) according to the preceding claim, wherein the separator element (104) comprises a varnish and/or insert having a thickness of between 100 and 300 microns to correspondingly separate the adhesive label (101) from the sealing membrane coverage (103). 4. Adhesive valve (100) according to one of the preceding claims, wherein the adhesive label (101) and/or the covering membrane (103) are configured to adhere to each other by electrostatic action in at least the second zone (B) of the covering membrane (103), so that the channel defined by said second zone (B) is closed to seal when not ? crossed by a fluid coming from the first incision (102) of the adhesive label (101). 5. Adhesive valve (100) according to one of the preceding claims, wherein the adhesive label (101) and/or the covering membrane (103) have at least one non-stick portion (E) configured in such a way as to prevent or oppose adhesion reciprocal of the adhesive label 101 and of the covering membrane 104 by electrostatic action or by the action of the Van der Waals forces in the first zone A and/or in the second zone B. 6. Adhesive valve (100) according to one of the preceding claims, wherein said at least one first incision (102) forms a plurality of of holes (102a) passing through the adhesive label (101); the lower surface (101b) of the adhesive label (101) has a non-adhesive operating portion (106); at least some of said holes (102a) extend from said operating portion (106) through the adhesive label (101). The adhesive valve (100) according to the preceding claim, wherein the lower surface (101b) of the adhesive label (101) is? covered with a first adhesive (101c) where said operating portion (106) ? without said first adhesive (101c) or has a film covering said first adhesive (101c). 8. Adhesive valve (100) according to the preceding claim wherein said film is formed by a lacquer or a film in polymeric material. 9. Adhesive valve (100) according to one of the preceding claims, wherein the upper surface (101a) of the adhesive label (101) comprises at least one first portion, which is? facing a second portion of the covering membrane (103) so as to form said first zone (A) and/or said second zone (B); said first portion and/or said second portion are optional: - without adhesive; - covered by an adhesive that ? coated with a non-stick layer comprising a lacquer and/or a polymeric material film. Adhesive valve (100) according to one of claims 1 to 8 wherein the upper surface (101a) of the adhesive label (101) comprises at least one first portion, which is? facing a second portion of the covering membrane (103) so as to form said first zone (A) and/or said second zone (B); where one of said first portion and said second portion? covered with a third adhesive (108), the other being covered with a non-stick material, for example with a silicone coating, capable of counteracting an adhesion action of said third adhesive (108) on it. 11. Adhesive valve (100) according to one of the preceding claims which comprises a protective membrane (107) fixed on the cover membrane (103) and/or on the adhesive label (101) to cover them so as to protect them from interactions with objects foreign to the adhesive valve (100). The adhesive valve (100) according to the preceding claim comprising a third adhesive (108) which secures the protective membrane (107) to the cover membrane (103) where between the protective membrane (107) and the cover membrane (103) ? there is at least one adhesive-free area (D) positioned and/or shaped to limit a separation stress of the covering membrane (103) from the adhesive label (101), which is generated by a retention action by the protective membrane (107) on the cover membrane (103) following a deflection of the adhesive valve (100). A preform (1000) comprising a sheet (200) for forming a food container which has two surfaces and has at least one second incision (201) connecting the two surfaces; said blank (1000) comprising an adhesive valve (100) according to one of the preceding claims which covers the second incision (201) such that at least one first incision (102) is superimposed on at least one second incision (201). A food container which comprises a blank (1000) according to claim 13, and which has an internal compartment for accommodating food on which it is placed. the second incision (201) of the sheet (200) faces to be crossed by a fluid contained in the internal compartment and having a higher pressure than the pressure outside said food container. A reservoir (2000) for adhesive valve applicator (100) comprising: - a support membrane (2001) having an operative face; - a plurality? of adhesive valves (100) according to one of claims 1 to 12 applied to said operative face removably fixed. 16. Tank (2000) according to claim 15 wherein the support membrane (2001) consists of a tape which develops mainly in a longitudinal development direction along which a plurality of of said adhesive valves (100) to form at least one row. The tank (2000) according to one of claims 15 and 16 wherein said adhesive valves (100) are fixed to said operating face by said first adhesive (101c). The method for manufacturing an adhesive valve (100) according to one of claims 1 to 12, which comprises the following steps: - step A of applying a first adhesive (101c) to a bottom surface (101b) of a first layer; - step B of etching the first layer to make said at least one first etching (102); - step C of fixing a second layer to an upper surface (101a) of the first layer by means of a second adhesive (105) so as to form the first area (A), the second area (B) and the third area (C) of said adhesive valves (100); - step D of cutting the first layer and/or the second layer to respectively obtain said adhesive label (101) and/or said covering membrane (103). The method according to the preceding claim, which comprises a step E of applying said separator element (104) between said first layer and said second layer. The method according to claim 18 or 19, which comprises a step F of applying said first layer to a support membrane (2001) which is cuttable to form a tank (2000) according to one of claims 15 to 17. 21. Process according to one of claims 18 or 20, which comprises a step G of fixing a third layer to an upper face of the second layer and a step H of cutting the third layer to obtain the protective membrane (107) of the adhesive valve ( 100) according to claim 10 or 11. 22. Process according to one of the preceding claims, wherein the first layer, the second layer and the possible third layer are strips worked continuously along one processing direction; called phase D? carried out by continuous or register die-cutting.