WO2022023525A1

WO2022023525A1 - Protective mask and functional part

Info

Publication number: WO2022023525A1
Application number: PCT/EP2021/071396
Authority: WO
Inventors: Pasko Todorov PASKOV; Peter BABOURKOV; Stanislav Tchavdarov PETKOV; Stanislav PETKOV; Vezhen Ivanov IVANOV; Uwe KÄRGEL
Original assignee: Sd Sensitive Diaper Gmbh
Priority date: 2020-07-31
Filing date: 2021-07-30
Publication date: 2022-02-03

Abstract

A protective mask comprises a main body and a functional part for breath- triggered release of a virus and/or bacteria neutralizing substance. The functional part is provided on the inner side of the main body and is arranged to face the mouth-nose region of a user's face. The functional part comprises a material having the ability of moisture triggered release of the virus and/or bacteria neutralizing substance, preferably at least one metal for releasing virus and/or bacteria neutralizing ions in a moist environment.

Description

PROTECTIVE MASK AND FUNCTIONAL PART

The present invention relates to a protective mask to be worn by a user and to a functional part for use with the protective mask.

There are various conventional structures of protective masks made from different materials in single-layer or multi-layer arrangements, with or without valves and additional filters. Their general principle is to filter the external pollutants and pathogens in order to prevent them from reaching the lungs of the user.

Conventional protective masks aim to reduce or neutralize external pollutants. However, conventional protective masks do not address pathogens exhaled by the user of the mask.

An average of about 250 species of microorganisms - viruses, bacteria and fungi - live in the oral cavity and lungs of a person. The immune system of a healthy person fights the microorganisms (microbial life) and they fail to multiply to the point of endangering the person's health. During normal breathing, some of the microorganisms that are present in the exhaled breath are transmitted to the environment. Most of them die very quickly after being exhaled due to environmental factors: UV rays, oxygen, ozone and others.

However, when a person puts on a mask for protection against air pollution or microorganisms, the exhaled air is also filtered by the mask and some of the pathogens in the exhaled breath remain inside. As the mask is located in close proximity to the skin of the person being a user, "ideal" conditions for the rapid multiplication of exhaled microorganisms are created, namely optimal temperature and humidity as well as a lack of enemies, because the immune system is not present. Exhaled breath temperature varies around 33-36° C while humidity may reach 100%. Under the optimum conditions created, microorganisms begin to multiply at a rapid rate and several generations are created within a short time, thereby growing exponentially. During inhalation, a person absorbs them back into the lungs, but in much larger quantities, which may cause an immune system failure. As a result, the likelihood of developing a disease increases significantly.

Some conventional masks address this problem by treating the fabric of the mask with substances containing silver compounds or colloidal silver nanoparticles. These products use the well-known property of colloidal silver to block vital enzymes for the growth of viruses, bacteria and fungi, thus preventing their reproduction and destroying them. Prior art masks designed in this way are capable of limiting the populations of pathogenic microorganisms in the air inhaled by humans.

The effectiveness of the prior art masks is limited by the homogeneous distribution of colloidal silver in the mask textile, which does not take into account pathogens in the exhaled air. Most of the silver nanoparticles are located in the fabric of the product, and only a small part of them is located in the surface area near the skin and the mouth/nose area of the user of the protective mask. This creates preconditions for a rapid loss of the antimicrobial properties of the inner surface of the mask and the appearance of the problem described above.

EXTENDED SUMMARY OF THE INVENTION

According to studies carried out by the inventors, the effectiveness of a protective mask against microorganisms exhaled by the user can be greatly increased by arranging a functional part near the skin of the user and by taking into consideration the air exhaled by the user.

The object of the invention is to provide a protective mask and a functional part having an increased effectiveness against microorganisms exhaled by the user.

This object is achieved by a protective mask and a functional part according to the following items.

1. Protective mask comprising a main body and a functional part for breath- triggered release of a virus and/or bacteria neutralizing substance, said functional part being provided on the inner side of the main body and arranged to face the mouth-nose region of a user's face. The functional part comprises a material having the ability of moisture triggered release of the virus and/or bacteria neutralizing substance. This material is preferably at least one metal for releasing virus and/or bacteria neutralizing ions in a moist environment, said material being more preferably silver or silver alloy.

According to the invention, a release of a virus and/or bacteria neutralizing substance is triggered by a breath of the user, and a functional part therefor is arranged facing the mouth-nose region of the user so as to utilize the breath. For example, the functional part may exhibit a temperature dependent release rate of the neutralizing substance, wherein the air exhaled by the user changes local temperatures of the functional part so as to trigger or increase the release of the neutralizing substance. Thereby, the air exhaled by the user is immediately subjected to treatment by the neutralizing substance. Consequently, pathogens (microorganisms, namely virus and/or bacteria) are neutralized when the user exhales air comprising the pathogens. As a result, an anti-pathogen effect is exhibited, the air exhaled by the user is treated more effectively, and the effectiveness against microorganisms inhaled and exhaled by the user (mask effectiveness) is increased.

According to studies carried out by the inventors, areas with higher and lower humidity form depending on the distance from the mouth or nose of the user. Each humidity area causes a degree of moisture to build up in, on or around the functional part. When the functional part comprises a material that reacts to moisture, the different humidity areas and corresponding moisture degrees ensure that the neutralizing substance can be released more reliably, thereby increasing mask effectiveness.

A material of the functional part, preferably structured as a metal or metal coated mesh or non-woven fabric, is active during exhalation, since temperature and humidity in the area of the metal increase, which leads to an increased release of ions. In addition, there may be areas with higher and lower humidity depending on the distance from the mouth. The movement of air during inhalation and exhalation causes electrification of the metal and depending on the distance from the mouth or nose, local potentials are different due to differences in temperature, humidity and speed of air movement through the structure. This leads to a flow of weak electric currents and thus further increases the release of silver ions.

Most of the exhaled microorganisms fall on the metal structure due to the difference in potentials. Furthermore, the remainder of the exhaled microorganisms have to pass a transition area between the metal structure and the main body of the mask. Both the metal or metal coated structure and the transition area are saturated with metal ions, which kill pathogenic microorganisms and/or stop their growth. Accordingly, mask effectiveness can be increased further.

In addition, some of the ions may be inhaled by the user of the mask and thus support the work of the immune system. Consequently, pathogenic microorganisms in the oral cavity and lungs are destroyed to a greater extent.

2. Protective mask according to item 1, wherein the functional part comprises at least one metal for releasing virus and/or bacteria neutralizing ions in a moist environment. The protective mask further comprises a battery being electrically connected to the metal so as to increase the release of ions.

With the above technical measures, more neutralizing substance (ions) can be released. Accordingly, mask effectiveness can be increased further.

3. Protective mask according to one of items 1 or 2, wherein the functional part comprises multiple layers formed of metal or metal coated meshes and/or non-woven fabric structures stacked upon each other. In addition hydrophilic separating layers are preferably interposed between said layers.

With the above structure, it is possible to provide layers of meshes and/or non- woven fabric structures configured to have a high permeability, while a total reaction area of the functional part can be maintained or even increased. Accordingly, a pressure drop of air passing through the functional part can be reduced, thereby improving the permeability of the mask. On the other hand, the neutralizing substance release rate is proportional to the reaction area of the functional part. Consequently, when pressure drop is reduced while surface area is maintained or increased, both user comfort and/or mask effectiveness can be increased.

By preferably providing hydrophilic separating layers between the functional layers, moisture generation in the meshes can be increased and thus the neutralizing substance releasing effect can be improved. Preferably, the separating layers have a higher breath permeability than the functional part so as to maintain user comfort.

4. Protective mask according to one of items 1 to 3, said mask further comprising at least one physiologically compatible layer covering the side of the functional part turned away from the main body and being able to be brought in contact with the user's face.

With the above structure, user comfort is further increased. In addition, the likelihood of skin irritation in hypersensitive users is further reduced.

Furthermore, in the protective mask according to item 4, a breath permeability of the physiologically compatible layer is higher than the breath permeability of the functional part.

With the above structure, the physiologically compatible layer does not interfere with the functional part. In addition, user comfort is improved.

Furthermore, in the protective mask according to item 4, a humidity absorption ability of the physiologically compatible layer is preferably the same or lower than the humidity absorption ability of the functional part.

With the above structure, the physiologically compatible layer does not remove humidity before the humid exhaled air reaches the functional part. Accordingly, the physiologically compatible layer does not interfere with the neutralizing substance release effectiveness of the functional part.

5. Protective mask according to one of items 1 to 4, wherein a portion of the main body covering the functional part comprises an air flow control mechanism configured such that its inhalation permeability is higher than that of the functional part, and its exhalation permeability is lower than that of the functional part.

With a high inhalation permeability during inhalation, user comfort is improved. For example, the inhalation permeability may be greatly increased by a valve that is open during inhalation, allowing more air to pass through the functional part.

When the exhalation permeability of the mask is the lower than that of the functional part, it is possible to keep humidity in the mask during exhalation by the user. For example, the exhalation permeability may be greatly decreased by a valve that limits air flow during exhalation. Thereby, humidity and thus moisture within the functional part are increased, which triggers the release of more neutralizing substance.

Accordingly, when the user exhales, air rich in neutralizing substance is trapped in the mask, and the pathogens in the trapped air are neutralized. When the user then inhales, fresh air from outside the mask passes through the functional part so as to be treated with the neutralizing substance. The air rich in neutralizing substance is mixed with the fresh air and also inhaled by the user. Thereby, mask effectiveness is increased.

6. Protective mask according to one of items 1 to 5, wherein the functional part has a higher breath permeability than a cover portion of the main body by which it is covered.

With the above structure, the functional part does not negatively affect breathing effort by the user compared to a mask comprising only the main body. Thereby, the user's comfort is increased, allowing an uninterrupted wearing of the mask so as to increase mask effectiveness.

7. Protective mask according to one of items 1 to 6, wherein the functional part has a higher humidity absorption ability than a cover portion of the main body by which it is covered.

When a cover portion of the main body covers a portion of the functional part, the cover portion may absorb a large part of the humidity that helps trigger the release of neutralizing substance. Accordingly, the cover portion may negatively affect the release of neutralizing substance. Hence, it is preferable that the functional part has a higher humidity absorption ability so as to absorb (convert into moisture) a large part of the humidity of the exhaled air in order to release more reliably the neutralizing substance, thereby increasing mask effectiveness.

8. Functional part for saturating moist air or water with metal ions, said functional part comprising a mesh and/or non-woven fabric structure, preferably comprising a substrate made of polymer or carbon, wherein the surface of the substrate is provided with a porous solid coating of deposited silver or silver alloy nanoparticles and/or clusters thereof.

A functional part having the above features provides a highly developed and highly reactive metal surface having a very high efficiency in releasing virus and/or bacteria neutralizing ions in a moist environment.

9. Functional part according to item 8, wherein the average diameter of the silver nanoparticles is between 1 and 50 nm, preferably between 5 and 30 nm.

According to studies carried out by the inventors, the above ranges result in the most advantageous ion release capability. Thereby, the effect of saturating moist air or water with silver ions is further improved.

10. Functional part according to item 8 or 9, wherein the porosity of the coating has a lower limit of at least 10 %, preferably at least 40 %, more preferably at least 60 %, while the upper limit of the porosity is only required to be lower than a porosity being able to impair the integrity of said coating, preferably not higher than 80 %.

Increasing porosity reduces the total mass of active ion releasing substance and thus the total ion release capability, while decreasing porosity reduces the total surface area available for reaction and thus also reduces the total ion release capability. According to studies carried out by the inventors, the above ranges result in the most advantageous ion release capability. Thereby, the effect of saturating moist air or water with silver ions is further improved.

With respect to the above, the porosity of the coating is evaluated by measuring the weight of the substrate before and after the deposition of the coating, and the density is then calculated and compared to the theoretical density of the silver (10,5 g.cm ³ ) or the respective silver alloy.

11. Functional part according to one of items 8 to 10, wherein the substrate substantially consists of fibers having an average diameter of 50 to 100 pm.

12. Functional part according to one of items 8 to 11, wherein the thickness of the coating is between 0,1 and 3 pm, preferably between 0, 3 and 1,5 pm.

According to studies carried out by the inventors, the above ranges result in the most advantageous ion release capability while minimizing the total mass of coating material, thereby also minimizing costs. Accordingly, the effect of saturating moist air or water with silver ions relative to the total costs can be improved.

13. Functional part according to one of items 8 to 12, wherein the silver alloy particles substantially consist of Ag and Cu, preferably Ag, Cu and Mo.

The above metals have a powerful bactericidal effect. The strength of this effect is in the order: Ag; Cu; Au. Silver (Ag) has an effect six times as powerful as copper (Cu), which in turn has an effect three times as strong as gold (Au). However, copper has a toxic dose, unlike silver. In excess, copper and its compounds begin to act as inhibitors of molybdenum (Mo), which in turn is involved in the formation of over 50 enzymes and is an important component in a large number of metabolic processes, including the formation of uric acid. From this point of view copper is unsuitable for daily use without additional alloy materials being present.

Most preferably, the coating is formed from an alloy of silver, copper and molybdenum (Ag, Cu, Mo). In this way the synergistic effect of the action of the three metals is obtained and the total effect is much greater. Molybdenum is also a powerful immunomodulator and is important as a trace metal.

14. Functional part according to item 13, wherein the silver alloy particles consist of 5 to 10 % Cu with the residual being Ag, or preferably 0,2 to 0,5 % Mo, 6 to 9 % Cu with the residual being Ag.

According to studies carried out by the inventors, the above ranges result in the most preferable synergistic effect and the most advantageous ion release capability. Thereby, the effect of saturating moist air or water with silver ions is further improved.

The silver and silver alloy coatings on the substrate used as functional (cidal) part according to the above items 8 to 14 can be obtained by using different methods for silver and silver alloy nanoparticles application on the substrate, said coverings having in particular a high efficiency in ionizing the inhaled moist air and thus in inhibiting virus infection and prevent viral migration. For the purpose of the present invention physical vapor deposition (PVD) methods are preferably used as dry deposition methods, for example like magnetron DC sputtering, plasma enhanced magnetron sputtering and pulsed laser deposition (PLD).

Particularly efficient is a low temperature (70°C) magnetron deposition process which is particularly suitable for the deposition of silver coatings on thermally sensitive polymeric substrates. This low temperature deposition method can preferably combine magnetron sputtering with a neutral atom beam (Saddle Field) plasma source.

For growing silver and silver alloy nanoparticles for producing nanostructured coatings with a continuous porosity on unheated substrates, it is particularly efficient to use direct current (DC) magnetron sputtering. By common varying the sputtering conditions including target-substrate distance, deposition time, sputter gas pressure and sputtering current, the size of the deposited nanoparticles and the porosity of the obtained nanostructured coating can be efficiently adjusted. For example, the shorter the target-substrate distance, the higher the total amount of deposited Ag, and, thus, the larger the Ag nanoparticle size will be. The thus grown metallic coatings have sponge-like morphology characterized by metallic continuity in three dimensions with continuous porosity on the sub-micron scale.

With the above structure, a functional part capable of efficiently saturating moist air or water with silver ions is provided. While the above-explained methods are the most preferable, other coating methods can be used like chemical and electrochemical known in the art.

15. Protective mask according to one of items 1 to 7, said mask comprising a functional part (2) according to one of items 8 to 14.

A combination of the protective mask and the functional part according to the present invention results in an optimal virus and/or bacteria neutralizing effect.

16. Protective mask according to one of items 1 to 7 or 15, wherein the functional part is formed as a module being detachably attachable to or into the main body.

When the functional part is a module being detachably attachable to or into the main body, it is possible to exchange the functional part in order to extend the service lifetime of the protective mask. Replacement modules can maintain the mask effectiveness. Used modules can be replaced by new modules or reprocessed to a functionally new state, for example by disinfection and reapplication of the silver surface coating. Thereby, mask effectiveness is maintained at a high level over an extended period of the mask's lifetime. Furthermore, maintenance costs can be reduced compared to a case in which the protective mask is used as a consumable. 17. Protective mask according to one of items 1 to 7 or 15, wherein the functional part protrudes into the main body or a cavity thereof by having a pyramid or bell-like cross section decreasing toward the outer side of the main body.

According to studies by the inventors, the air exhaled by the user spreads in a nearly radial manner so as to form a half-circular or bell-like shape. With the above structure, overlap of the functional part and the air is increased by also providing the functional part in a depth direction of the mask. Consequently, it is possible to use the moisture generated by the exhaled air more efficiently. Accordingly, mask effectiveness can be increased.

According to another aspect, the functional part includes a metal mesh of longitudinal and transverse metal threads.

The above structure provides a simple configuration that is easy to manufacture using conventional weaving means. Furthermore, a regular mesh provides a high durability and improves user comfort when the mesh contacts the user's skin.

According to another aspect, the metal threads have a diameter of lpm to lOOpm.

According to studies carried out by the inventors, metal threads having a diameter in the above range are best suitable for appropriate ion release. This range is sufficient for ion release. On the other hand, diameters in this range result in an appropriate pressure drop of air passing through the functional part, which maintains the user's ease of breathing. More preferably, the diameter of the metal threads is in the range between 20 pm (micrometers) to 50pm in order to improve further the above-described effects.

The distance between the threads of the mesh is preferably in the range between 0.1 to 5mm, more preferably between 0.2 mm to 1 mm. According to studies by the inventors, these ranges result in an appropriate permeability so as to allow easy breathing by the user while still maintaining sufficient ion release.

According to another aspect, the metal threads substantially consist of copper. By using copper, a cost-efficient metal structure having a high electrical conductivity is provided.

According to another aspect, a silver surface coating with a thickness of up to 30pm is applied to the metal threads.

Silver exhibits excellent anti-bacterial and anti-viral properties, thereby improving the mask effectiveness. Furthermore, the likelihood of skin irritation is very low for most users.

More preferably, the thickness of the silver surface coating is in the range between 0,1 and 3 pm, most preferably between 0, 3 and 1,5 pm. According to studies carried out by the inventors, a silver surface coating falling within the most preferred range exhibits sufficient ion releasing properties while avoiding excessive costs.

According to another aspect, instead of using metal threads, a thread of fibers, preferably polymer fibers or carbon fibers, is provided, a copper surface coating is preferably applied to the thread, a silver surface coating with a thickness between 0,1 and 3 pm, most preferably between 0, 3 and 1,5 pm is applied to the copper surface coating or the thread, and a mesh is formed by the fibers before or after coating.

By providing any thread with a copper surface coating and a silver surface coating, the above advantages can be achieved with an even more cost-efficient structure. The basis may be a polymer fiber, which is metallized. The polymer fiber can be different types of plastics capable of metallization. Carbon fiber can also be used as a base. The thickness of the metallization or coating layer can vary from 0.1pm to l-2pm. Metallization can be unimetallic, wherein a single coating layer of silver is applied, or bimetallic, wherein a first coating layer is made of copper and a second coating layer is made of silver. The mesh can also be woven or woven from non-metallized fibers and subsequently metallized as a whole mesh.

Furthermore, in bimetallic metallization, the ion releasing effect is further increased due to the flow of electric current between the two layers of metals: copper (Cu) and silver (Ag). The intensity of ion release increases in proportion to the current flowing.

When the silver particles are electrified, the dielectric of the base (insulator) is polarized, in which dipoles are formed, which enhances the overall effect of the separation of silver ions. Thus, the concentration of silver ions increases many times and enhances the bactericidal and antiviral effect of the mask.

According to another aspect, the functional part is centered at a nose area of the user.

During general everyday use of a protective mask, most of the breathing occurs through the nose. Accordingly, centering the functional part at a nose area of the user results in high mask effectiveness and long-term comfort at a low cost.

Alternatively, the functional part may be centered at a mouth area of the user. This increases mask effectiveness and long-term comfort when the mask is worn in situations, in which speaking, coughing, sneezing or other acts involving mouth breathing are expected.

According to another aspect, the functional part is formed as an insert being attachable to the concave side of a bowl-shaped main body.

With the above structure, the main body accommodates safely the functional part. Accordingly, the functional part is more resilient to outside influences. Furthermore, since the functional part is an attachable insert, it can be replaced during the mask's lifetime. Thereby, mask effectiveness is maintained at a high level over an extended period of the mask's lifetime. Furthermore, maintenance costs can be reduced compared to a case in which the protective mask is used as a consumable.

According to another aspect, the principle of operation of the functional of the protective mask may be used in a separate functional part for saturating air and water with silver ions in order to disinfect and improve human health. The silver- plated mesh may be mounted in an air or water path where the released silver ions may flow towards a human, for example in a filter module of an air conditioning system or a pool water supply. In order to release a larger amount of ions, an electric current with a low voltage of 1-3V and an adjustable current may be passed through the grid in order to optimize the release of ions. For this purpose, a sensor may be placed after the mesh in the direction of fluid movement, which measures the concentration of ions. With the help of the feedback loop constructed in this way, the exact amount of ions released can be controlled.

According to another aspect, the functional part may be used for saturating air with silver ions in a different manner. Electrification of the mesh may be provided by a high constant voltage (HV DC) in the order of 5-20 kV and a current around or below ImA. In this implementation, an additional effect is achieved. In addition to silver ions, the air is filled with a large amount of negative ions of the gases that make it up. The amount of both types of ions can be controlled with the same feedback loop. When the breathes through a mask in the area between the face and the mask, an area with an increased concentration of carbon dioxide and carbon monoxide is created, which makes breathing difficult.

In summary, the present invention enables a combination of comfortable inhalation and excellent mask effectiveness.

Without special measures, microorganisms from the skin and from the exhaled air may stick on the inside of the mask: bacteria, viruses, fungi, plasmoids and others. Without the influence of the immune system, they develop unhindered and with each inhalation increase their concentration in the human body, mainly in the oral cavity and lungs. In these regards, the protective mask according to the invention has the following advantages:

The silver ions and nanoparticles that are released from the functional part (e.g. silver mesh) built into the mask have a powerful bactericidal, antifungal and antiviral action. All microbes on the inner surface of the mask are destroyed in minutes.

The mask facilitates breathing. Due to the movement of air through the functional part, small amounts of (e.g. charged silver ions) are released into the inhaled air. Accordingly, a slight ionization of the air with a negative charge is obtained, which is perceived by the body as fresh air, and the temperature around the mouth decreases slightly.

When breathing, the inside of the mask is moistened and this leads to the dissolution of part of the carbon dioxide and carbon monoxide in it. Some of the solution interacts with the functional part and is neutralized. This leads to a decrease in the concentration of the two gases, which is perceived as easier breathing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a protective mask according to a first embodiment of the invention.

FIG. 2 shows a perspective view of a metal mesh according to the first embodiment.

FIG. 3 shows a longitudinal sectional view of a copper thread with silver surface coating according to the first embodiment.

FIG. 4 shows a longitudinal sectional view of a steel thread with copper and silver surface coating according to a first modification of the first embodiment.

FIG. 5 shows a perspective view of a protective mask with a battery according to a second modification of the first embodiment.

FIG. 6 shows a perspective view of a protective mask according to a third modification of the first embodiment.

FIG. 7 shows a sectional view of a protective mask according to a second embodiment. FIG. 8 shows a sectional view of a protective mask according to a modification of the second embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

First embodiment

A first embodiment of a protective mask according to the invention is shown in FIGS. 1 to 3.

The protective mask according to the first embodiment shown in FIG. 1 comprises a main body 1, a metal mesh 2 and elastic straps 5.

The main body 1 is made of a single layer of protective fabric in this embodiment. Examples for a single-layer protective fabric are a pure cotton woven fabric. Alternatively, the main body 1 may be a multi-layer protective fabric, for example a cotton layer combined with a polypropylene filter layer, or may include several bodies.

The metal mesh 2 is attached to the inner surface of the main body 1 facing the user. The metal mesh 2 is a biaxial mesh that comprises longitudinal and transverse metal threads 3 (FIG. 2). The metal threads 3 in the first embodiment are copper threads that are covered in silver surface coating 4 (FIG. 3) and woven by conventional means. Copper threads as a base for the metal mesh 2 provide a stable and inexpensive base structure having excellent electrical conductivity, while silver exhibits excellent anti-bacterial and anti-viral properties. Furthermore, the likelihood of silver causing skin irritation is very low for most users. According to studies carried out by the inventors, a structure having copper threads with a diameter of 20pm to 50pm and a silver surface coating 4 with a thickness between 2 pm and 4pm exhibits sufficient ion releasing properties while avoiding excessive costs. However, depending on the desired mask properties, the metal threads may have a diameter of 1pm to 100pm, and a silver surface coating with a thickness of up to 30pm may be applied. Furthermore, instead of being woven, the metal threads 3 may be provided as a non-woven fabric with a regular or irregular structure.

The distance between the threads in the metal mesh 2 according to this embodiment can vary from 0.1 mm to 5 mm, depending on the diameter of the threads, the intensity of the intended antimicrobial effect and a breath permeability considered comfortable by the user. All other things being equal, the intensity of the process of release of silver ions increases by decreasing the distance between the longitudinal and transverse metal threads of the mesh. This in turn enhances the antimicrobial effect of the mask with respect to both exhaled and inhaled pathogens. On the other hand, breath permeability and thus comfort also decrease when decreasing the distance between the metal threads. Accordingly, the distance between the threads 3 of the metal mesh 2 is preferably from 0.2 mm to

1 mm in order to combine appropriate comfort and appropriate mask effectiveness.

With the above structure, the metal mesh 2 has a higher breath permeability than a cover portion of the main body 1 by which it is covered. Thereby, the metal mesh

2 does not negatively affect breathing effort by the user. Consequently, the user's comfort is increased. Furthermore, the metal mesh 2 has a higher humidity absorption ability than the main body 1. As a result, a large part of the humidity of the exhaled air is absorbed (converted into moisture on the metal mesh 2) in order to release more reliably the neutralizing substance, thereby also increasing mask effectiveness.

The attachment of the metal mesh 2 to the main body 1 in the two embodiments can be carried out in a number of ways known in the background art. According to the first embodiments, the mesh 2 is glued to the main body 1. Alternatively, the metal mesh 2 can be attached to the main body 1 via fixing tapes located on the outer edges of the metal mesh 2 and glued to the main body 1, or can be embedded in or formed integrally with the main body 1.

The elastic straps 5 are attached to the main body 1 of the protective mask, thereby allowing to secure the mask around the ears of the user. Alternatively, the mask can be provided with any other known means for attaching the mask to the user, for example head and/or neck straps.

The protective mask according to the first embodiment works during exhalation as temperature and humidity in the area of the metal mesh 2 increase, which leads to an increased release of silver ions. There are also areas with higher and lower humidity depending on the distance from the mouth. The movement of air during inhalation and exhalation causes electrification of the metal mesh 2. Depending on the distance from the mouth, local potentials along the metal mesh 2 are different due to the different speed of air movement through the metal mesh 2. This leads to the flow of weak electric currents in the range of 100-200 pA (picoamperes) to 200-300 nA (nanoamperes) in the metal mesh 2, which increases the release of silver ions.

Most of the exhaled microorganisms fall on the metal mesh 2 due to the difference in potentials or in the area between the metal mesh 2 and the main body 1 of the mask. These areas are most saturated with silver ions, which kill and stop the growth of pathogenic microorganisms. In addition, some of the silver ions are inhaled by the user of the mask and thus support the work of the immune system. Consequently, pathogenic microorganisms in the oral cavity and lungs are destroyed to a greater extent.

According to the above, the metal mesh 2 in the first embodiment serves as a functional part, and the breath of the user triggers the release of silver ions as a virus and/or bacteria neutralizing substance. The moisture triggers further release of silver ions. The metal mesh 2 provides a higher breath permeability and higher humidity absorption ability than a cover portion of the main body 1 that covers the metal mesh 2. Therefore, the protective mask according to the first embodiment provides excellent mask effectiveness and user comfort.

First modification of first embodiment

In a first modification of the first embodiment, the metal threads 3 of the mesh 2 are provided as steel threads with a diameter of 20pm to 50pm. As shown in FIG. 4, the steel threads 3 are first coated by a copper surface coating 6 with a thickness of lpm to 3pm, and then the copper surface coating 6 is in turn coated by a silver surface coating with a thickness between 2 pm and 4pm. The above-cited ranges may be adapted as appropriate according to the disclosure of the first embodiment.

By providing steel threads with a copper surface coating and a silver surface coating, the advantageous effects of the first embodiment can be achieved with an even more cost-efficient structure. In addition, steel is more resilient and durable than copper, thereby increasing user comfort and mask longevity.

Second modification of first embodiment

In a second modification of the first embodiment, the protective mask is provided with an additional external power supply. In this modification, the external power supply is a battery 7. As shown in FIG. 5, the battery 7 is provided in a pocket 8 and is connected to the metal mesh 2 via a wiring 9. The discharge of the battery 7 feeding the metal mesh 2 is controlled by a conventional electronic circuit (not shown). The discharge of the battery 7 and the corresponding current flowing through the metal mesh 2 is maintained in the range of 500nA to IpA. This leads to a significant increase in the release of silver ions, whereby the effectiveness of the mask is increased.

Third modification of first embodiment

In a third modification of the first embodiment, the protective mask is provided with an physiologically compatible layer 10 covering the metal mesh 2 between the metal mesh 2 and the user (FIG. 6).

In this modification, the physiologically compatible layer 10 is a gauze material. Accordingly, the likelihood of skin irritation in hypersensitive users is reduced. Any other material is suitable for the physiologically compatible layer 10 so long as the physiologically compatible layer 10 is biocompatible with the user and does not irritate his or her skin . As shown in FIG. 6, the physiologically compatible layer 10 completely covers the metal mesh 2. Alternatively, the physiologically compatible layer 10 may cover only parts of the metal mesh 2, for example parts that come into contact with the user's skin. Thereby, interference with the function of the metal mesh 2 (functional part) by the physiologically compatible layer 10 is reduced, resulting in an increased mask effectiveness.

Second embodiment

A second embodiment of the protective mask according to the invention is shown in FIG. 7. In the second embodiment, the functional part protrudes into the main body 1 and has a pyramid cross section decreasing toward the outer side of the main body 1.

The functional part comprises multiple metal meshes 2 stacked upon each other so as to form the pyramid cross-section. The metal meshes 2 are embedded in the fabric of the main body 1, as visible in FIG. 7. Separating layers 11 are provided between the meshes, wherein the separating layers are hydrophilic so as to improve humidity absorption. Alternatively, the functional part may be configured by a non-woven fabric and/or may have a bell-like cross section. The separating layers 11 may be omitted.

With this structure, a pressure drop of air passing through the functional part can be reduced due to the multiple meshes 2 that can be provided with greater distance between the metal threads, thereby improving the permeability of the mask. On the other hand, the neutralizing substance release rate is proportional to the reaction area of the functional part, the reaction area being increased by the multiple meshes. Consequently, when pressure drop is reduced while surface area is maintained or increased, both user comfort and/or mask effectiveness can be increased.

The protective mask of the second embodiment further comprises an air flow control mechanism, specifically a valve 12 depicted as a symbol in FIG. 7. The valve allows air to flow freely through the metal meshes 2 during inhalation, and restricts air flow through the metal meshes 2 during exhalation. Accordingly, an inhalation permeability of the valve is higher than that of the metal meshes 2 (serving as functional part), and user comfort is improved.

During exhalation, air flow is restricted by the valve 12 to a lower air flow rate than during inhalation. Accordingly, an exhalation permeability of the valve 12 is lower than that of the metal meshes 2. In other words, exhalation air flow is more restricted than the inhalation air flow. Thereby, it is possible to keep humidity in the mask during exhalation by the user. Therefore, humidity and thus moisture within the metal meshes 2 are increased, which triggers the release of more neutralizing substance.

As a consequence, when the user exhales, air rich in neutralizing substance is trapped in the mask, and the pathogens in the trapped air are neutralized. When the user then inhales, fresh air from outside the mask passes through the functional part so as to be treated with the neutralizing substance. The air rich in neutralizing substance is mixed with treated fresh air, and the air mixture is inhaled by the user. Thereby, neutralizing substance is inhaled, and mask effectiveness is increased.

Consequently, the second embodiment enables a combination of comfortable inhalation and excellent mask effectiveness.

Modification of second embodiment

FIG. 8 shows a sectional view of a protective mask according to a modification of the second embodiment.

In this modification, the metal meshes 2 and separating layers 11 are attached to a physiologically compatible layer 10 as described above with respect to the third modification of the first embodiment. The physiologically compatible layer 10 is attached to the main body 1 by adhesion or other conventional means. In this modification, the physiologically compatible layer 10 is attached to the main body 1 by a resealable attachment part 13. The resealable attachment part 13 reversibly (detachably and re-attachably) seals the physiologically compatible layer 10 against the main body 1. The main body 1 is sealed against the user's face; alternatively, parts of the physiologically compatible layer 10 may restrict air from flowing therethrough. In both cases, exhaled air is forced to flow through the metal meshes 2.

Meanwhile, the metal meshes 2 and the separating layers 11 are not attached to the main body 1. Accordingly, the metal meshes 2, the separating layers 11 and the physiologically compatible layer 10 together form a module that is detachably attachable to the main body 1.

With the above structure, it is possible to exchange the module comprising the metal meshes 2 in order to extend the service lifetime of the protective mask. New or reprocessed modules can maintain the mask effectiveness. Used modules can be replaced by new modules or reprocessed to a functionally new state. Thereby, mask effectiveness is maintained at a high level over an extended period of the mask's lifetime. Furthermore, maintenance costs can be reduced compared to a case in which the protective mask is used as a consumable.

Furthermore, the main body 1 in this modification is made of a stiff material, e.g. a resin, and has a bowl-shape. The modules that include the metal meshes 2 (the functional part) constitute an insert being insertable into and attachable to the concave side of the bowl-shaped main body 1. Thereby, the main body 1 accommodates safely the metal meshes 2. Accordingly, the metal meshes 2 are more resilient to outside influences. Furthermore, since the metal meshes 2 are part of an attachable insert, they can be replaced during the mask's lifetime. Thereby, mask effectiveness is maintained at a high level over an extended period of the mask's lifetime. Furthermore, maintenance costs can be reduced compared to a case in which the protective mask is used as a consumable.

It is not necessary to provide the physiologically compatible layer 10 and/or the separating layers 11, as long as the metal meshes 2 form any type of module or insert that can be attached to and detached from the mask. Examples for alternative structures are cartridges, replaceable layers that can be inserted into a pocket provided in the mask or the like. Further modifications

The modifications to the first embodiment may also be provided to the second embodiment and vice-versa.

As a further modification to the first or second embodiments, the main body 1 may be made of a resin, a plastic or any other stiff material. The stiff material is more appropriate for reusable masks.

As a further modification to the first or second embodiments, the main body 1 may be configured so as to cover parts of the face or the whole face while sealing against the skin of the face. Such a structure constitutes a sealed mask that is sealed against the user's face and does not allow any untreated air to enter or exit the mask. The sealed mask offers better user protection.

The above-described protective mask is preferably used in the field of medical hygiene supplies, in particular as personal protective equipment against pathogens and pollutants in the ambient air entering the body by inhalation and also against pathogens exiting the body by exhalation. However, the use is not limited thereto, and the above-described protective mask may also be used as a reusable high- protection mask in any setting where biological hazards are likely, for example in a hospital or during hazardous material removal.

Claims

1. Protective mask comprising a main body (1) and a functional part (2) for breath-triggered release of a virus and/or bacteria neutralizing substance, said functional part being provided on the inner side of the main body and arranged to face the mouth-nose region of a user's face, wherein the functional part comprises a material having the ability of moisture triggered release of the virus and/or bacteria neutralizing substance, preferably at least one metal for releasing virus and/or bacteria neutralizing ions in a moist environment.

2. Protective mask according to claim 1, wherein the material of the functional part (2) comprises at least one metal for releasing virus and/or bacteria neutralizing ions in a moist environment, said mask further comprising a battery (7) being electrically connected to the metal so as to increase the release of ions.

3. Protective mask according to claim 1 or 2, wherein the functional part (2) comprises multiple layers formed of metal/metal coated meshes and/or non- woven fabric structures (2) stacked upon each other, preferably with hydrophilic separating layers (11) provided between said layers.

4. Protective mask according to one of claims 1 to 3, said mask further comprising at least one physiologically compatible layer (10) covering the side of the functional part (2) turned away from the main body (1) and being able to be brought in contact with the user's face, wherein the breath permeability of the physiologically compatible layer is higher than the breath permeability of the functional part, and wherein the humidity absorption ability of the physiologically compatible layer (10) is preferably the same or lower than the humidity absorption ability of the functional part (2).

5. Protective mask according to one of claims 1 to 4, wherein a portion of the main body (1) covering the functional part (2) comprises an air flow control mechanism (12) configured such that its inhalation permeability is higher than that of the functional part, and its exhalation permeability is lower than that of the functional part.

6. Protective mask according to one of claims 1 to 5, wherein the functional part has a higher breath permeability than a cover portion of the main body by which it is covered.

7. Protective mask according to one of claims 1 or 6, wherein the functional part has a higher humidity absorption ability than a cover portion of the main body by which it is covered.

9. Functional part according to claim 8, wherein the average diameter of the silver nanoparticles is between 1 and 50 nm, preferably between 5 and 30 nm.

10. Functional part according to claim 8 or 9, wherein the porosity of the coating has a lower limit of at least 10 %, preferably at least 40 %, more preferably at least 60 %, while the upper limit of the porosity is only required to be lower than a porosity being able to impair the integrity of said coating, preferably not higher than 80 %.

11. Functional part according to one of claims 8 to 10, wherein the substrate substantially consists of fibers having an average diameter of 50 to 100 pm.

12. Functional part according to one of claims 8 to 11, wherein the thickness of the coating is between 0,1 and 3 pm, preferably between 0, 3 and 1,5 pm.

13. Functional part according to one of claims 8 to 12, wherein the silver alloy particles substantially consist of Ag and Cu, preferably Ag, Cu and Mo.

14. Functional part according to claim 13, wherein the silver alloy particles consist of 5 to 10 % Cu with the residual being Ag, or preferably 0,2 to 0,5 % Mo, 6 to 9 % Cu with the residual being Ag.

15. Protective mask according to one of claims 1 to 7, said mask comprising a functional part (2) according to one of claims 8 to 14.