WO2022074691A1

WO2022074691A1 - Sanitizing device

Info

Publication number: WO2022074691A1
Application number: PCT/IT2021/050298
Authority: WO
Inventors: Federico ZAT; Claudio ALLEGRANZI; Massimo VERDI; Lucio TOMASELLA
Original assignee: WIPPYIDEA S.r.l.
Priority date: 2020-10-06
Filing date: 2021-09-29
Publication date: 2022-04-14
Also published as: IT202000023452A1

Abstract

A sanitizing device (10) comprises a micro-perforated film (12) provided on a first side with an adhesive layer (14) and on a second side, opposite the first side, with at least one photocatalytic layer (16) based on titanium dioxide.

Description

“SANITIZING DEVICE”

FIELD OF THE INVENTION

Embodiments described here concern a sanitizing device, in particular for internal spaces, by means of a photocatalysis process.

BACKGROUND OF THE INVENTION

The catalyst properties of titanium dioxide (TiO₂) are known, in degrading numerous organic and non-organic compounds by means of oxidation when they are exposed to solar or artificial ultraviolet (UV) light, by means of a process called photocatalysis.

The photocatalysis performed by TiO₂ is known to be advantageously used to purify and sanitize the air of spaces from germs or microorganisms, such as viruses, bacteria, fungi and others, and polluting species produced by man.

The surfaces treated to be made photocatalytic allow to improve the quality of the air simply by exploiting sunlight or artificial light. The main field of application concerns the reduction of smog levels in polluted urban areas with heavy traffic.

Typically, TiO₂ is deposited as a thin film or layer of nanoparticles on the surface of the external covering elements of buildings such as, for example, facade panels, plaster, roof tiles, etc.

In particular, it is known that firms operating in the building trade treat construction materials, for example cement materials, ceramic materials, photovoltaic paints, etc. to create eco-sustainable buildings whose large vertical and non- vertical development area, treated with TiO₂, provides an important tool against atmospheric pollution.

In addition, thanks to the particular characteristics that TiO₂ provides to the building materials, the external surfaces of these eco-sustainable buildings are protected from blackening caused by pollution.

Air pollution derives mainly from the transport sector, the industrial sector, the activity of electric power plants and incinerators, domestic heating, the use of pesticides in the agricultural sector and dust deriving from the mining sector. The main pollutant agents present in the atmosphere are: carbon dioxide (CO₂), sulfur oxides (SO_X), nitrogen oxides (NO_X), carbon monoxide (CO), polycyclic aromatic hydrocarbons (PAH), volatile organic compounds (VOC) and particulate matter (PM 10).

In principle, the decomposition mechanisms of the various pollutant agents follow the structure of the oxidative decomposition of NOx.

In the presence of sunlight and humidity in the air, the NOx molecules that c -ome i -nto c -ontact w . i -th t -he n _x -hotocatalv Jt -ic s -urface u -nder _Cg₎o- t -he f -ollow . i —ng reactions:

The OH* radicals that are generated on the surface of the nanoparticle act as powerful oxidants of toxic compounds such as NO and NO2 producing NO3-, which is much less dangerous. The nitrate ion, in fact, can recombine with alkaline ions present in the pores of the surface, forming inert salts, or it can be washed away as a very diluted nitric acid.

The high specific surface area of the nanoparticles allows a large, highly reactive area to be exposed to the air when exposed to sunlight (or artificial light), converting atmospheric pollutants into harmless by-products which can subsequently be washed away by the action of atmospheric precipitation.

TiO₂ is also used inside buildings, in particular to reduce or even eliminate bad smells, for which VOCs are mainly responsible.

The most common substances that belong to this category are: trichlorethylene (C2HC13), acetone (C3H6O), 1 -butanol (C4H10O), butanal (C4H8O), m-xylene (C8H10), 1,3 -butanediene (c4H6), toluene (C6H5CH3), formaldehyde (CH2O).

The biocidal/sanitizing effect of TiO₂ is also known.

The sanitizing action is produced by the free radicals produced, that cause damage to the external membrane, protein or phospholipid, of the microorganisms that come into contact with the photocatalytic surface.

Without the protection offered by the external cell wall, the internal cytoplasmic membranes, or other structures, are attacked by the same free radicals, causing an outflow of intracellular fluids that leads the microorganism to rapid death or fragmentation.

One disadvantage of the state of the art is that it is not possible to deposit TiO₂ in the surfaces of external and internal spaces of buildings once these have been completed, except by means of operations of renovation or extraordinary replacement.

Therefore, updating an existing building or space ex novo with TiO₂ requires long times and high costs, which slow down possible renovation works using this technology.

Furthermore, in the uses mentioned above, TiO₂ is typically mixed with resins or dyes or other substances, therefore, since it is not pure, it has a low level of effectiveness, particularly in the degradation of microorganisms.

The recent SARS-CoV-2 pandemic has greatly changed the daily habits of the world population, for example access to closed spaces of buildings (shops, restaurants, offices, etc.) and public transport (buses, trains, airplanes, etc.) with the purpose of limiting the spread of the virus.

These spaces are, in fact, considered at high risk of transmission of airborne diseases, due to their low air exchange and/or high density and passage of people.

For now, the contrast measures adopted to make these spaces usable again, at least partly, are, in particular, fixed-number access, the obligation to wear a surgical mask, or similar, and the use of alcoholic solutions for cleaning the hands.

However, these measures have no direct effect on the air of the space and on the particles that are suspended in it, such as viral particles, which can therefore potentially be breathed in by the people who frequent the space, giving continuity to the transmission and spread of the disease.

However it is possible to sanitize these spaces using sanitizing operations based on chemical substances which, in addition to being expensive, would also make these spaces inaccessible due to the necessary times required to air the premises. Moreover, this airing would make the sanitization operation at least partly useless since it would allow the access from the outside of other particles into the sanitized space.

Document US2019/0336626A1 describes a photocatalytic device comprising a transparent support coated with a photocatalytic film, which is applied in such a way that the light first passes through the support and then through the photocatalytic layer before reaching the space to be sanitized. US5919422A describes a photo- catalyst for operations to sterilize and purify water, which comprises a substrate, a titanium dioxide-based film and a lightemitting diode having a wavelength between 360 and 400 nm, that is, below the visible light range.

There is therefore a need to perfect a sanitizing device which can overcome at

To do this, it is necessary to solve the technical problem of obtaining a sanitizing device applicable to any surface, which guarantees high sanitization of the surrounding space even in conditions of poor light, without requiring dedicated lighting devices.

In particular, one purpose of the present invention is to provide a sanitizing device with effective and continuous action over time against microorganisms and other pollutants of the air in spaces.

Another purpose of the present invention is to provide an economical and eco- sustainable sanitizing device.

It is also the purpose of the present invention to provide a sanitizing device that is easy and immediate to apply and effective from the moment of installation.

Another purpose of the present invention is also to provide a sanitizing device which remains active over time, and which can also increase its sanitization efficacy.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

The invention provides a sanitizing device that comprises a micro-perforated film provided on a first side with an adhesive layer and on a second side, opposite the first side, with at least one photocatalytic layer based on titanium dioxide (TiO₂) in a percentage equal to or greater than 90% weight/weight.

In some embodiments, the percentage of TiO₂ can preferably be equal to or greater than 94%.

The sanitizing device exploits the photocatalytic activity of the TiO₂ in order to destroy inorganic and organic compounds.

The sanitizing device can preferably be used in indoor spaces, and is particularly advantageous if used in those spaces with high risk of airborne transmission of pathologies caused by poor air exchange and/or high density and passage of people.

The photocatalytic and, therefore, also anti -microbial function of the TiO₂ is almost continuous and performs its function even in the presence of people.

It is therefore possible to eliminate or at least reduce the presence of unwanted particles, such as for example viral particles, from such spaces in a way that lasts over time without preventing access for people.

By means of the adhesive layer it is possible to apply the sanitizing device rapidly and quickly on a surface, preferably flat and regular.

The sanitizing device has an immeasurably smaller thickness than the area it can cover, which makes it functional in not occupying space useful for the normal activities or function of the space in which it is installed.

The area that the sanitizing device can cover can be deliberately made to measure for the surface on which it is to be applied.

The shape of the sanitizing device can be adapted to the surface on which it is to be applied.

The shape and/or area can be quickly adapted by the user by removing the excess part/parts on the spot with a sharp object (for example a pair of scissors).

The sanitizing device can be applied to suitable surfaces of permanent or semipermanent structures inside the space (for example walls, panels or glass) or furnishing structures (for example, furniture or appliances).

The adhesive layer can be configured to allow the sanitizing device to be detached from the surface on which it is applied in order to reposition it on another surface.

Preferred embodiments provide that the sanitizing device is transparent in order to be applied to transparent or reflective surfaces such as glass or mirrors.

In this way, the photocatalytic activity can be activated by external light and/or by artificial light inside the space. This characteristic makes it less noticeable, if not even invisible, when applied to the surfaces of permanent or semi-permanent structures or furnishings.

This aspect makes the sanitizing device particularly suitable to be applied in spaces characterized by a large glass surface, allowing to make the most of the available area especially when other suitable surfaces are not available.

be sanitized it is convenient to supply a correlated surface of photocatalytic layer in order to obtain an adequate sanitization of the volume of air and that, in some spaces, the only possible way is, in fact, to use the glass surface.

Some non-limiting examples of spaces with a large glass surface with low air exchange and/or high density and passage of people can be the cabins of public transport means.

Since the cabin of the means of transport is characterized by a large glass surface, the invention described here advantageously exploits this surface in order to reach the suitable surface of photocatalytic layer to obtain an adequate sanitization, without detracting useful space for boarding and accommodating users.

In any case, it is not necessary that the films are expressly positioned on glass: they can also be applied on any other surface whatsoever, preferably smooth, as long as it is in the proximity of a light source.

For example, in the specific case of buses, they can be applied to the ceiling, to overhead luggage racks or to dividing panels.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- figs. 1 is a detailed lateral view of a sanitizing device in accordance with some embodiments described here;

- figs. 2 is a sequence of use of a sanitizing device in accordance with some embodiments described here;

- figs. 3 and 4 are a schematic representation of possible applications of a sanitizing device. To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be combined or incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

We will now refer in detail to the possible embodiments of the invention, of which one or more examples are shown in the attached drawings, by way of a non-limiting illustration. The phraseology and terminology used here is also for the purposes of providing non-limiting examples.

All the intervals reported here shall be understood to include the extremes, including those that report an interval “between” two values, unless otherwise indicated.

The present description also includes the intervals that derive from uniting or overlapping two or more intervals described, unless otherwise indicated.

The present description also includes the intervals that can derive from the combination of two or more values taken at different points, unless otherwise indicated.

With reference to the attached drawings, a sanitizing device is described, identified as a whole with reference number 10.

With reference to fig. 1, the sanitizing device 10 comprises a micro-perforated film 12 provided on a first side with an adhesive layer 14 and on a second side, opposite the first side, with at least one photocatalytic layer 16 based on titanium dioxide (TiO₂) in a percentage equal to or greater than 90% weight/weight.

In some embodiments, the percentage of TiO₂ can preferably be equal to or greater than 92%, or also preferably equal to or greater than 94%.

The film 12, the adhesive layer 14 and the photocatalytic layer 16 form a photocatalytic assembly 18.

The photocatalytic layer 16 provides a germicidal function to the sanitizing device 10, making it suitable to eliminate bacteria, viruses, fungi, pollen, mites and to substantially reduce smog, purify the air from unpleasant smells of smoke, food, perspiration, decomposition, mold, paints, petrol, diesel and other pollutants. In particular, given its germicidal property, the sanitizing device 10 can advantageously be used in spaces characterized by a high influx and density of people in which there is therefore a high risk of coming into contact with or breathing in microorganisms.

The photocatalytic layer 16 can have a thickness between 1 and 8 pm,

more preferably between 2 and 4 pm.

The film 12 can have a thickness between 20 and 100 pm, preferably between 30 and 90 pm, more preferably between 40 and 80 pm, even more preferably between 50 and 70 pm.

The photocatalytic layer 16 is applied directly onto the surface of the film 12 and is not mixed with the components thereof. In this way, it is possible to provide a “pure” photocatalytic layer with high photocatalytic performance.

In particular, the titanium dioxide (TiO₂) is applied to the outside of the film 12.

For example, the photocatalytic layer 16 can be supplied in a substantially fluid form and be, preferably, spread or sprayed onto the surface of the film 12, on the side opposite the adhesive layer, in such a way that, during use, the photocatalytic layer 16 faces the space to be sanitized.

In one variant, the sanitizing device 10 can comprise two overlapping photocatalytic layers 16. Preferably, a second photocatalytic layer 16 is applied on a first photocatalytic layer 16 when the first is at least partly dry.

In another variant, the sanitizing device 10 comprises a photocatalytic layer 16 with another overlapping photocatalytic layer 16 that can comprise particles suitable to improve transmittance, for example particles of silicon dioxide SiO₂.

The adhesive layer 14 allows the sanitizing device 10 to be easily applied to any surface whatsoever, preferably to flat and regular surfaces.

The adhesive layer 14 comprises an adhesive substance or a mixture of adhesive substances that allow to attach/detach the sanitizing device 10 from one surface in order to relocate it on another. This procedure can be performed several times with no or minimal loss of adhesive power of the adhesive substance or of the mixture of adhesive substances. The adhesive substance or the mixture of adhesive substances can preferably not leave any residues on the surface when detached.

According to some embodiments, the film 12, the adhesive layer 14 and the photocatalytic layer 16 can be transparent.

This characteristic means that the sanitizing device 10 can be advantageously applied to transparent or light-reflecting surfaces, such as glass or mirrors, only modifying their function to a limited extent.

This characteristic makes the sanitizing device 10 particularly suitable to be used in those spaces at least partly confined by walls or panels, the surface area of which is largely covered by windows, small windows, portholes, glazing or mirrors or suchlike.

For example, this sanitizing device 10 can be applied inside closed spaces such as rooms of homes or buildings for commercial use, or even inside motor vehicles.

Some embodiments can provide that the sanitizing device 10 is coupled to a protective film 20 associated with the adhesive layer 14 and with an area coherent with the latter in order to prevent the deposit of impurities before the application of the sanitizing device 10 on a surface.

When the sanitizing device 10 is provided with the protective film 20, the latter has to be separated from the photocatalytic assembly 18 in order to associate it, by way of example, with a glass pane V, as shown in fig. 2.

The particular micro-perforated structure of the film 12 means that the adhesion to a substantially smooth surface does not cause, or at least reduces, the formation of air bubbles between the two surfaces in contact.

In this way, the sanitizing device 10 is difficult to detect, at least visually, once applied to a transparent (or reflective) surface.

Furthermore, the micro-perforated structure 12 allows to manufacture sanitizing devices 10 even of large sizes, for example coherent with the sizes of the windows of buildings for civil or commercial use, or even the windows of vehicles or trains, or exhibitors in commercial spaces, making it quick and simple to apply the sanitizing device 10 on them.

Some advantageous, non-limiting examples of application of the sanitizing device 10 can be the application to the windows of public transport means (buses, trams, subways, trains, etc.), to the portholes of airliners or ships, cable cars, greenhouses and closed panoramic spaces.

These spaces, in fact, are often densely populated and characterized by a very limited air exchange, thus generating the conditions in which microorganisms can persist and, in the event of conditions favorable to their replication, even saturate this space.

as above can represent a serious problem, because the probability of transmission of pathologies related to these microorganisms, in particular those with airborne transmission, increases exponentially.

Providing such spaces with the sanitizing device 10 would allow to reduce the load of suspended microorganisms and therefore the transmission of correlated pathologies.

In some embodiments, the photocatalytic layer 16 comprises silver ions in a percentage comprised between 2% and 10% weight/weight.

In some embodiments, the percentage of silver ions can preferably be comprised between 3% and 8% weight/weight.

In other embodiments, the percentage of silver ions can preferably be between 4% and 7%, even more preferably between 4% and 6%.

The silver ions allow to activate the photocatalysis reaction with any light with a wavelength in the visible spectrum other than UV light, such as for example full spectrum artificial light.

In this way, it is possible to gain advantage from the sanitizing device 10 even in spaces that are poorly lit by sunlight or that are by necessity illuminated by artificial light that does not emit UV, such as for example subway carriages, surgical rooms, school environments, changing rooms, spaces of the food services and hotels industry sector, etc.

In some embodiments, the photocatalytic layer 16 comprises graphene in a percentage between 0.25% and 3% w/w.

In some embodiments, the percentage of graphene can preferably be between 0.5% and 2%.

The graphene provides an antistatic effect to the photocatalytic layer 16. In some embodiments, the photocatalytic layer 16 comprises carbon nanotubes.

The photocatalytic layer 16 is provided with a contact angle of about 12° which causes the water to form a thin film instead of a droplet, and which causes dirt to slide off easily. This aspect, called hyper hydrophobia, means that the photocatalytic layer 16 is provided with an anti-fog and self-cleaning effect.

According to other embodiments, the photocatalytic layer 16 comprises silicon dioxide SiO₂, preferably in a percentage comprised between 0.25% and 3% weight/ weight, even more preferably between 0.5% and 2%.

The titanium dioxide, since it advantageously provides an energy conserving effect, allows the sanitization efficacy to be maintained over time. Furthermore, it also allows to keep the performance of the sanitizing device 10 active, and possibly even increase it over time.

In other words, once the photocatalytic layer 16 is illuminated and “activated” with a light source, it will continue to remain active even if the light source is turned off or reduced, possibly slightly decreasing the sanitization efficacy. That is to say that the sanitizing device 10 can continue to sanitize the space in which it is applied even when it is not directly illuminated, or even during the night.

The Applicant has also tested that a sanitizing device 10 according to the invention, when positioned in a dimly lit space, can initially have a minimal sanitization efficacy, which however tends to increase over time until it reaches a value substantially corresponding to the one that is achieved when the sanitizing device 10 is optimally illuminated by a visible light source.

Figs. 3 and 4 are used to present two possible spaces in which the use of the invention described here may be advantageous.

The number of sanitizing devices 10 and the surface they cover is intended for illustrative purposes only and not as an optimal configuration of use. By optimal configuration of use we mean the surface of the sanitizing device 10 required to sanitize a volume of air of the space in which the sanitizing devices 10 are present in a given predefined amount of time.

Fig. 3 shows a bus B in which a plurality of sanitizing devices 10 is applied inside the cabin, in particular on the face facing toward the inside of the glass panes V, of the windows and of the entrance/exit doors which delimit the cabin perimeter.

In this case, the sanitizing devices 10 advantageously allow to sanitize the internal space of a bus B in a substantially continuous way at least during its entire use, reducing or eliminating any bacterial loads that could be transmitted from one user to another.

Fig. 4 shows an example office workstation comprising two desks S, on each of which a respective computer C is positioned. Each desk S is separated by a panel P, for example made of plexiglass, on which the sanitizing device 10 is

Also in this case, the sanitizing devices 10 advantageously allow to sanitize the space both surrounding each desk S, and also possibly in an area around them. It is clear that modifications and/or additions of parts may be made to the sanitizing device as described heretofore, without departing from the field and scope of the present invention as defined by the claims.

In the following claims, the sole purpose of the references in brackets is to facilitate reading: they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.

Claims

1. Sanitizing device (10) characterized in that it comprises a micro-perforated film (12) provided on a first side with an adhesive layer (14) and on a second side, opposite the first side, with at least one photocatalytic layer (16) based on titanium dioxide in a percentage equal to or greater than 90% weight/weight, preferably equal to or greater than 92%.

2. Device as in claim 1, characterized in that said photocatalytic layer (16) comprises silver ions in a percentage comprised between 2% and 10% weight/weight, preferably between 3% and 8%.

3. Device as in claim 1 or 2, characterized in that said photocatalytic layer (16) comprises graphene in a percentage comprised between 0.25% and 3% weight/weight, preferably between 0.5% and 2%.

4. Device as in any claim hereinbefore, characterized in that said photocatalytic layer (16) comprises silicon dioxide in a percentage comprised between 0.25% and 3% weight/weight, preferably between 0.5% and 2%.

5. Device as in any claim hereinbefore, characterized in that said photocatalytic layer (16) comprises carbon nanotubes.

6. Device as in any claim hereinbefore, characterized in that said photocatalytic layer (16) has a thickness between 1 and 8 pm, preferably between 1.5 and 6 pm, more preferably between 1.5 and 4.5 pm, even more preferably between 2 and 4 pm.

7. Device as in any claim hereinbefore, characterized in that said film (12), said adhesive layer (14) and said photocatalytic layer (16) are transparent.

8. Device as in any claim hereinbefore, characterized in that said film (12) has a thickness comprised between 20 and 100 pm, preferably between 30 and 90 pm, more preferably between 40 and 80 pm, even more preferably between 50 and 70 pm.

9. Method to produce a sanitizing device (10) characterized in that it provides to supply a micro-perforated film (12) and apply, on one side, an adhesive layer (14) and, on an opposite side, at least one photocatalytic layer (16) comprising titanium dioxide in a percentage greater than 90% weight/weight, preferably equal to or greater than 92%.

10. Method as in claim 9, characterized in that said photocatalytic layer (16) comprises silver ions in a percentage comprised between 2% and 10% weight/weight, preferably between 3% and 8% weight/weight.

11. Method as in claim 9 or 10, characterized in that said photocatalytic layer

(16) comprises graphene in a percentage between 0.25% and 3% weight/weight, preferably between 0.5% and 2%.

photocatalytic layer (16) comprises silicon dioxide in a percentage comprised between 0.25% and 3% weight/weight, preferably between 0.5% and 2%.

13. Method as in any claim from 9 to 12, characterized in that said film (12), said adhesive layer (14) and said photocatalytic layer (16) are transparent.

14. Method as in any claim from 9 to 13, characterized in that it provides to apply a second photocatalytic layer (16) onto a first photocatalytic layer (16) when the first photocatalytic layer (16) is at least partly dry.