The present invention relates to a mask for protecting the respiratory tract of a user, comprising a covering element of the mouth and nose of the user and means for constraining the covering element to the user's head. The covering element preferably consists of an internal fabric layer facing the user's face, an external fabric layer and at least a first intermediate layer, interposed between the external layer and the internal layer.

The masks known in the state of the art are currently used in a wide variety of applications to protect the respiratory system from airborne particles, from dust, for example for the defence against fine dust and other pollutants or from pathogens such as bacteria or viruses.

Specifically, the present patent application relates to a half-mask, i.e. , a mask adapted to cover the lower part of the face, in particular only the mouth, the nose and the parts of the face adjacent thereto, avoiding the inhalation of moisture, dust or other bodies suspended in air.

The masks typically consist of one or more layers of materials permeable to air, typically an internal layer, a filtering layer and a covering layer. Some masks include a covering which creates an internal chamber enclosing the mouth and nose which are thus separated from the external environment and an elastic band constraining the covering to the user's face. In such masks, the covering is entirely in filtering material and, usually, in non-woven fabric. Alternatively, it is impermeable to air (for example rubber, neoprene or silicone) and provided with interchangeable filters.

When air passes through the mask, the filtering layer retains the contaminants contained within the air flow, preventing their inhalation by the user. Similarly, the exhaled air passing through the mask is purified of pathogens and contaminants, allowing the protection of people nearby.

So-called "surgical" masks, thanks to low production and purchase costs and ease of use, are widespread, both inside hospitals and as an instrument for individual protection to be purchased in pharmacies, during daily life.

Most masks known in the state of the art, in particular masks without specific elements, do not offer an efficient barrier to the diffusion of droplets suspended in air, therefore they do not protect the user from contamination in the case of widespread pathogens in the form of drops and defend even less against viruses of the size of tens of nanometres (1 nanometre = 10 ^L -9 metres).

On the other hand, the masks known in the state of art with special filtering means, such as FFP2, FFP3 or similar filters, create a barrier effect against the wearer, prevent drops from contaminating the wearer, but do not block any infected droplets generated by the wearer of the mask.

It follows that an asymptomatic person, despite wearing known state-of-the-art masks, can infect other people nearby. In the case of a widespread disease, such as the Covid-19 pandemic which is taking place these days, the population is required to wear masks continuously in order to infect as few people as possible.

It has been proven that diseases such as Covid-19 spread precisely because of the ease of contagion among people, as a cough or a sneeze is sufficient to infect the people nearby, both through droplets containing the virus, having dimensions of a few microns, and through aerosol with dimensions of the individual particles of the order of hundreds of nanometres, therefore difficult to shield by most of the daily-use masks.

In fact, if it is considered that drops of saliva move at about 80 km/h for a cough and at about 300 km/h for a sneeze and taking into account the methods of diffusion and propagation in the air of the nanometric aerosol, it can be understood how the presence of a mask which generates a total barrier effect of such drops is a fundamental requirement to limit diffusion.

Such a concept is valid not only for pandemics such as Covid-19, but also for seasonal illnesses such as influenza, colds, etc., or other, still unknown pathogens.

Currently certified masks have developed in non-woven fabric, except for some companies whose conversion has led to the development of products related to their experience and their technical know-how. Some of these masks have interchangeable filters, others are compact, others still have a valve, or are rigid with the application of the valve to ensure breathability. In general, most use four layers of filtration using four different types of non-woven fabric (TNT).

Today the market, also improperly, tends to consider FFP2 masks as the maximum safety standard for protection against COVID-19 contamination.

Currently FFP2 masks are not made of fabric, therefore they are made almost entirely of TNT with four or more filtration layers. As reported above, some of these also have the valve for ensuring adequate breathability.

As anticipated, the masks known in the state of the art have disadvantages not only in relation to a lack of efficiency in creating a total barrier effect, i.e. , both in and out, against suspended droplets and aerosol, but also have negative aspects from the point of view of environmental impact.

In fact, most of the masks known in the state of the art are made of synthetic materials and are often disposable masks, i.e., they lose their filtering power after washing or disinfections following the first use.

If the majority of the population, and not only healthcare personnel or personnel who use masks as personal protective equipment during their work shift, were required to wear masks daily, the consumption of the latter would have disastrous effects on the environment due to the high amount of plastic material, which is not recyclable, to be disposed of. There is therefore a need not satisfied by the masks known in the state of the art to create a mask which solves the disadvantages exposed above, creating a barrier effect to and from the external environment and which has washability features. The present invention achieves the above objects by making a mask as previously described, in which the first intermediate layer consists of a layer of filtering non-woven fabric.

In addition, the external fabric layer has a nanostructured super- hydro-oleophobic breathable coating containing highly oxidizing nanoparticles - ROS (Reactive Oxide Species).

Such a configuration makes it possible to create a mask with a high hydro-oil repellent capacity, which creates a barrier effect against suspended droplets and aerosol, also consisting of pathogens only, which can have lipid surfaces outwards, with which they attach to surfaces or cells.

Barrier effect means a total shielding of the mouth and nose of the user wearing the mask object of the present invention.

The mask object of the present invention is configured as a personal protective equipment with the same filtering features as a mask of the FFP2 type, but with the possibility of being reused after washing the internal and external fabrics.

In fact, such fabrics can be washed, for example, by washing at 40°C, without deteriorating the filtering power of the first intermediate layer. To this is added the super-hydro-oleophobic treatment, with antibacterial and antiviral properties, which confers much higher safety standards both in terms of inactivation of pathogens and in terms of repulsion and poor adhesion thereof on the exposed parts of the mask, also reducing the transmissibility by contact with surfaces, ensuring good breathability.

The nanoparticle coating thus increases safety and ensures that the virus and, in general, the pathogens, are destroyed on the surface of the mask in a few hours. The nanostructured treatment gives the external surfaces a super- homniphobic behaviour (super hydro-oleophobic), which has the property of not letting pathogens (bacteria and viruses) adhere.

The presence of ROS nanoparticles also confers the ability to produce, both in the presence of light and in the dark, highly oxidizing radicals capable of destroying the cell membrane of bacteria and viruses, as well as their vital functions.

The super-hydro-oleophobic treatment also makes the mask of the present invention less dirty from both water-based and oily substances.

Such an aspect is particularly advantageous, also with regard to the reusability of the mask object of the present invention, since the retention of the aqueous and oily substances on the external surface of the mask prevents the same substances from deteriorating the first intermediate layer, i.e. , the filtering heart of the mask, while maintaining the protection of the respiratory tract.

The nanostructured treatment therefore preserves the filtering and active features even after several washes.

In addition, since the ROS nanoparticles are incorporated into the hydro-oleophobic treatment, which covers the fibres of the fabric, there are no problems with the user's breathing when the mask is worn, thus avoiding any type of release towards the user and towards the environment, as well as the total absence of metal ions, which over time can cause damage both to people and the environment.

By virtue of such features, the mask of the present invention can be certified as Personal Protective Equipment (INAIL) according to UNI 149:2009.

Nevertheless, in order to be able to place the mask on the market as a washable device, the certification as Personal Protective Equipment (INAIL) according to UNI 149:2009 is sufficient.

Preferably the internal fabric layer also comprises the nanostructured treatment.

Thereby, the fabric facing the user's face will also have the germicidal and virucidal features described above. In accordance with a preferred embodiment, the fabric of the external layer is made of polyester.

The use of polyester, in addition to giving the mask washability features, allows to obtain the sublimation printing of the fabric. By virtue of such a configuration, a filtering mask is obtained, washable and customizable, as it is possible to print any logo, image or writing on the external fabric.

According to a further embodiment, the fabric of the internal layer consists of cotton. The part in contact with the user's face is therefore made of cotton, which has hypoallergenic properties and does not create irritation in contact with the skin.

In particular, the cotton used has the ISO 18184 certification which, in combination with the nanotechnological treatment, certifies the destruction of the virus in a given period of time.

Cotton thus has undoubted advantages from the point of view of preserving the integrity of the skin with which the mask object of the present invention is in contact.

However, the use of cotton presents specific problems which are solved through the present invention.

In fact, the known state-of-the-art FFP2 masks have one or more filtering layers which are heat-sealed to each other.

Such a procedure would not be possible if a layer of cotton is used, as the heat-sealing would ruin the cotton, fraying it. According to the mask object of the present invention, the internal layer of cotton can be used by virtue of a seam of the internal layer of cotton with the external layer.

Such an aspect is more advantageous according to the embodiment which includes the external layer made of polyester, since it is possible to sew the internal layer of cotton to the polyester according to the sewing procedures known in the field of textile assembly.

In order to optimize the wearability and washability of the mask object of the present invention, a second intermediate layer consisting of non-woven fabric is included, which second intermediate layer has greater stiffness features with respect to the first intermediate layer.

Therefore, a layer of non-woven fabric is provided which is less filtering than the first intermediate layer, but more structured, to ensure greater resistance to the stresses used in the dust filtration tests, characteristic of FFP2-type masks.

As will be apparent from the illustration of an embodiment, according to a preferred embodiment, a third intermediate layer of non- woven fabric is included, made like the first intermediate layer.

Three intermediate layers are thus provided, arranged overlapping one another, where two are similarly made and have greater filtering features, while another has lower filtering features with respect to the other two, but provides structural features.

The presence of three layers has specific advantages, as it allows to obtain the same filtering power of a single layer which has the thickness of all three intermediate layers, but with greater breathability.

A very high filtering power is thus obtained, without excessively limiting breathability.

Also for the purpose of facilitating wearability, the constraining means consist of thread-like elements having the ends fixed to the covering element, at least one annular retaining element being present, so that the end of a thread-like element is inserted inside said annular element to form an eyelet.

As will be apparent from the illustration of some embodiments, the presence of the annular retaining element allows to tension the thread like elements in order to better adhere the mask to the face of the wearer who wears it.

Alternatively, it is possible to include restraining means consisting of elastic retaining elements sewn to the covering element.

Such elastic elements consist of materials which have a certain elasticity, such as Lycra fabrics.

Such fabrics are, first of all, particularly wearable as they do not exert excessive pressure on the user's ears, which has a feeling of greater comfort, and secondly are printable, therefore customizable, just like the external layer of polyester of the covering element.

According to a further embodiment of the mask object of the present invention, the covering element comprises at least two elongated stiffening elements, placed at the nose and chin of the user, in the worn condition of the mask.

Also in this case, a double elongated stiffening element, i.e. , so- called "nose clips", allows the mask to better adhere to the user's face.

Given the advantageous aspects described above related to the mask, the present invention also relates to a method for making a mask for protecting the respiratory tract of a user.

The method object of the present invention includes overlapping an external fabric layer, a first intermediate filtering layer and an external fabric layer. Furthermore, an application step is included on the external layer of a coating consisting of a nanostructured super-hydro-oleophobic breathable coating containing highly oxidizing nanoparticles - ROS (Reactive Oxide Species).

Such an application can be performed according to one or more of the manners known in the state of the art.

In particular, the application of super-hydro-oleophobic nanostructured breathable coating containing highly oxidizing nanoparticles - ROS (Reactive Oxide Species) can be applied both in immersion in industrial washing machines and by foulard treatment. ROS nanoparticles (such as ZnO, Zn-Ag, Ce02, Ti02, Ti02-Ag, Ti02-N and other nanoparticles having highly oxidizing and photocatalytic features) and ammonium quaternary salts are preferably inserted inside the super- hydro-oleophobic breathable treatment.

According to a possible embodiment of the method object of the present invention, the application step is performed directly on the fibres forming the external fabric, before making said fabric.

According to such a configuration, it is possible to make the active component directly on or inside the fibre before making the fabric by using sol-gel techniques, spinning, immersion, extrusion from nanocomposite granules.

Advantageously, the step of applying a super-homniphobic nanostructured coating is also carried out on the internal layer.

As described above, according to a preferred embodiment, a sublimation printing step of the fabric of the external layer is included.

According to a possible embodiment, to make the filtering core of the mask object of the present invention, a step is included for overlapping a first intermediate layer, a second intermediate layer and a third intermediate layer.

In addition, the external layer is fixed to the internal layer so as to create an internal chamber for housing the overlapping of the first, second, and third intermediate layers.

In particular, the external layer is fixed to the internal layer through a sewing process.

A sewing methodology known in the art, such as those known in the field of textile assembly, can be used.

Preferably, the external edge of the external layer is folded over and sewn at the edge of the internal layer.

It should be specified that to obtain the finished mask, a procedure for assembling the various parts is obviously included.

Firstly, the different materials which are cut to size are taken, i.e., to obtain the shape of the covering element of the mask object of the present invention.

Then the internal cotton layer is taken, the three intermediate layers of non-woven fabric and the four layers are cut.

The polyester layer adapted to form the external layer is then taken and cut to size.

After the cutting, the polyester layer is sublimated to achieve the desired printing and customization.

The choice to make the cut before sublimation allows to limit the waste of material. The external layer of polyester and the internal layer of cotton, once cut, are treated, i.e. , a covering is provided with a super-hydro-oleophobic nanostructured breathable coating performed after the cutting.

As anticipated, the anti-virus coating is preferably applied to the cotton through an immersion foulard bath, while on the polyester it is applied either in the same way or after sublimation with a washing machine and dryer.

According to a preferred embodiment, it is possible to include treating the external polyester layer and subsequently performing the sublimation printing.

Once all the layers have been cut and the external layer and the internal layer have been treated, the same layers are assembled by stitching the external edges of the internal layer and the internal layer, the stitching of which also fixes the external edges of the three intermediate layers.

As anticipated, it is possible to include stiffening elements, for example elongated metal elements, inserted into the fold of the external edge of the external layer.

After such a step of assembling the layers, it is possible to fix the constraining means to the covering element.

Once the mask is finished, it can be packaged inside a special container.

The container and mask can then be placed inside a combustion chamber, of an oven, which has a temperature such as not to ruin the filtering core of the mask and the container, but which allows the elimination of any germs and bacteria.

Finally, the present invention also relates to a kit for personal protective equipment comprising at least one mask for protecting the respiratory tract and a case adapted to contain said mask. The mask is made according to one or more of the features described above.

Advantageously the case is made of synthetic material, such as polyester, polybag or the like. By virtue of such a configuration it will be possible to keep the mask safely, as the case has the function of keeping the mask hermetically protected even after the washing and maintenance thereof.

From what has been described above, it is evident how the present invention makes it possible to create a mask comparable in degree of protection to masks of the FFP2 type known in the state of the art, but which is reusable, washable and customizable, having a layer of cotton in contact with the skin of the user.

Furthermore, the mask of the present invention includes, as described, constraining means, the length of which is easily adjustable, so as to adapt to the shapes and dimensions of the face of the users.

It should also be noted that the features of the intermediate layers of non-woven fabric, together with the treatment of the external fabric, confers a high filtering power, which creates a barrier effect also against dolomitic dust.

These and other features and advantages of the present invention will become clearer from the following description of some exemplary embodiments illustrated in the accompanying drawings in which: figure 1 shows a view of a possible embodiment of the mask object of the present invention; figure 2 illustrates a detail of the covering element belonging to the mask object of the present invention; figures 3a and 3b illustrate two possible embodiments of the constraining elements belonging to the mask object of the present invention; figures 4a and 4b illustrate two views of the kit object of the present invention according to a possible embodiment.

It should be noted that the figures attached to the present patent application show a possible embodiment of the mask for protecting the respiratory tract of a user object of the present invention to better understand its advantages and the features described.

Such an embodiment is therefore to be understood as purely illustrative and not limiting to the inventive concept of the present invention, namely to make a mask which allows to obtain a barrier effect of suspended droplets and aerosols and therefore has a high water repellency, maintaining the washability features of the mask and the consequent reuse thereof. In particular, figure 1 shows a view of the mask for protecting the respiratory tract object of the present invention, according to a possible embodiment.

The mask includes a covering element 1 of the user's mouth and nose and means for constraining the covering element 1 to the user's head.

As can be seen from figure 1 , the constraining means consist of thread-like elements 2, in particular elastic whose ends are fixed to the covering element.

The mask object of the present invention has one thread-like element 2 per side, so that in the worn condition of the mask, the thread like elements 2 surround the ears of the user and allow to fix the mask to the head of the user.

According to a possible embodiment, it is possible to include that the constraining elements are coupled to special tensioners and not necessarily fixed to the ears of the user.

The covering element 1 can comprise some seams 10 which serve to structure the mask and to give it rigidity and which contribute to maintaining the typical shape of FFP2 masks, i.e. , a pointed shape, which does not crush the user's nose, also visible from the polygonal shape of the front side of the covering element 1.

Figure 2 illustrates a detail of the covering element, consisting of an internal fabric layer 11 facing the user's face, an external fabric layer 13 and a first intermediate layer 12, interposed between the external layer 13 and the internal layer 11. In addition, the external fabric layer 13 has a nanostructured super- hydro-oleophobic breathable coating containing highly oxidizing nanoparticles - ROS (Reactive Oxide Species). Such a covering is obviously not illustrated in figure 2, but the deposition of droplets 3, which do not permeate the external fabric 13, shows the waterproofing function of such a covering.

Furthermore, the first intermediate layer consists of a layer of non- woven fabric material with a high filtering function.

Preferably, according to the variant illustrated in figure 2, the first intermediate layer constitutes the filtering core of the mask object of the present invention and comprises a first intermediate layer 120, a second intermediate layer 121 and a third intermediate layer 122.

The first intermediate layer 120 consists of non-woven fabric with features such as to make an active filtered layer capturing particles up to 0.3 microns.

The second intermediate layer 121 consists of non-woven fabric with features such as to make an electrostatic reinforcement layer capable of capturing dust and micro-organisms.

The third intermediate layer 122 is made of non-woven fabric with features such as to make an active filtering layer which captures particles up to 0.3 microns.

Furthermore, the external layer 13 is preferably made of polyester.

The internal layer 11 is instead preferably made of cotton and can also have a nanostructured super-hydro-oleophobic breathable coating containing highly oxidizing nanoparticles - ROS (Reactive Oxide Species), like the external layer 13.

Advantageously, the second intermediate layer 121 preferably has a weight of about 0.70 grams per square metre (g/rri2), while the first and third intermediate layers preferably have a weight of about 0.20 grams per square metre (g/rri2).

According to a preferred embodiment, the internal layer 11 is fixed to the external layer 13 by means of seams.

Generally, the external layer 13 of polyester is folded on itself near the edges and is sewn to the internal layer 11 of cotton, so as to create an internal chamber between the internal layer 11 and the external layer 13 in which the three intermediate layers 120, 121 and 122 can be housed.

Figure 3a illustrates a detail of the constraining means, as anticipated consisting of thread-like elements 2 (see figure 1 ), in particular of two thread-like elements 2, one on each side of the covering element 1.

Each thread-like element 2 is illustrated by an elastic or string 21 , whose cone ends are sewn to the covering element 1 .

The constraining means also have an annular retaining element 22, which, in the particular case of figure 3, consists of a rubber ring, of the o-ring type or the like.

As illustrated in figure 3a, before both ends of the elastic 21 are sewn to the covering element 1 , one end is inserted into the annular retaining element 22, folded over itself and inserted back into the annular retaining element 22 again from the same side as the first insertion.

Thereby, the elastic 21 forms an eyelet 210.

The eyelet 210 forms the "excess" of the elastic 21 in the case of elongation or shortening of the elastic 21 during the tensioning thereof to adapt the mask to the user's face, once worn.

Figure 3b illustrates a further embodiment of the constraining means of the covering element 1 to the user's ears.

In this case, the constraining means consist of elastic elements consisting of a binding 23 of elastic fabric, which has both ends sewn to the covering element 1.

The binding 23 does not need the elastic retaining elements 22 described above, since the elastic features thereof allow the length to be adjusted according to the user's face.

Furthermore, the bindings 23 are made of a polyester and Lycra fabric, so as to be lightweight on the user's ear, i.e., so as not to exert excessive pressure on the user's ears.

As mentioned above, moreover, the invention also relates to a kit, of which a possible embodiment is illustrated in figures 4a and 4b. In particular, the kit has a mask made according to one or more of the features described above and a case 4 aimed at containing such a mask.

The case 4 is preferably made of a synthetic material of the polyester type or the like, so as to be able to bear a sublimation print on the external layer, in order to make the pattern of the case 4 uniform with the pattern of the mask.

Furthermore, the case 4 has a mouth for inserting the mask and means for closing said mouth, which can be made in any of any of the ways known in the state of the art.

While the invention is susceptible to various modifications and alternative constructions, some preferred embodiments have been shown in the drawings and described in detail.

It should be understood, however, that there is no intention of limiting the invention to the specific illustrated embodiment but, on the contrary, it aims to cover all the modifications, alternative constructions, and equivalents falling within the scope of the invention as defined in the claims.

The use of "for example", "etc.", "or" refers to non-exclusive non- limiting alternatives, unless otherwise stated.

The use of "includes" means "includes but not limited to", unless otherwise stated.