FIBER MATERIAL FOR ANTIBACTERIAL AND / OR ANTIVIRAL USE, FILTER, MOUTH AND NOSE MASK AND INSERT FOR A MOUTH AND NOSE MASK

Description

[0001] The invention relates to a fiber material for antibacterial and / or antiviral use, a filter, a face mask, and an insert for a face mask. A method for producing a fiber material for antibacterial and / or antiviral use is also disclosed.

[0002] This type of fiber material can be used, for example, in antibacterial and / or antiviral filters or surgical face masks. Furthermore, the fiber material can be used in filters for respiratory protective devices, such as those described in KR102058075B1, or in air conditioning systems exposed to fluctuating ambient temperatures. These filters can often become damp during operation, for example, due to humidity or moisture contained in the air being breathed. This dampening is generally undesirable and can lead to filter deterioration and / or the need to replace the filters.

[0003] The invention is based on the objective of providing a fiber material that exhibits improved antibacterial and / or antiviral properties when moistened. It is further an object of the invention to provide a filter, a face mask, and a method for producing a fiber material (not according to the invention).

[0004] This problem is solved by a fiber material according to claim 1. The fiber material for antibacterial and / or antiviral use comprises fibers having metallic silver and manganese(IV) oxide, wherein the manganese(IV) oxide is in contact with the metallic silver at least partially, and wherein the manganese(IV) oxide and the metallic silver are present as particles larger than 10 µm. The fiber material is preferably designed for use in a gas-permeable filter and / or face mask.

[0005] The present invention makes it possible to keep fibrous materials and filters made from them largely free of microorganisms and viruses, even when they become damp. In the case of face masks, dampness is an indication that the mask should be disposed of and replaced with a new one. With the present invention, it is possible to use a damp mask for a significantly longer period of time.

[0006] It has been found that silver and manganese(IV) oxide can be applied very effectively to fibers and, when combined with the otherwise undesirable moisture in exhaled or ambient air, form oxygen radicals, also known as ROS (reactive oxygen species). These highly reactive oxygen species can damage proteins, lipids, RNA, or DNA, the components of bacteria and viruses, triggering a biochemical reaction that renders the bacteria and viruses harmless. This effect intensifies with increasing moisture content, significantly improving the service life and maximum permissible usage of such fiber materials and the filters and masks they contain.

[0007] The fibers can be, for example, cellulose fibers, plastic fibers, e.g. polypropylene, in particular microfibers made of polypropylene, ceramic fibers or mixtures thereof, and are advantageously supplied as fiber material in webs on rolls.

[0008] In another embodiment, the manganese(IV) oxide at least partially contacts the metallic silver. Furthermore, the manganese(IV) oxide and the metallic silver are present as particles larger than 10 µm. Using spray application methods known from the prior art, such as those that can also be used for the methods according to the invention, sizes of the resulting precipitate (i.e., the resulting particles or particle aggregates) of silver and manganese oxide larger than 10 µm are achievable. The size of 10 µm also advantageously ensures that the precipitate and its particles or particle aggregates are not nanoparticles.Particle accumulations with a minimum size of 10µm around non-respirable particles, which is essential especially for use in mouth and nose protection masks or respiratory air filters, even if the adhesion to the fiber material is very good.

[0009] In another embodiment, the fiber material has the following surface composition: 10 to 25%, in particular 14 to 20%, silver, 10 to 25%, in particular 16 to 19%, manganese, wherein the manganese is in particular present as a manganese oxide.

[0010] The surface composition can be determined by EDX analysis (energy-dispersive X-ray spectroscopy) using a scanning electron microscope (SEM). SEM EDX analysis is used to determine the chemical elemental composition for spatially resolved material analyses. This method can be used to analyze surface composition. Preferably, the surface composition further contains 10 to 25%, particularly 12 to 18%, oxygen, which may be present, in particular, together with manganese as a manganese oxide. In other words, the surface composition on the fiber material is a particle distribution (aggregations of particles / individual particles) of metallic silver and manganese(IV) oxide deposited on the surface of the fiber material.

[0011] In another embodiment, at least parts of the manganese(IV) oxide are arranged, at least section by section, between the fibers and the silver. It has been found that this significantly improves the adhesion of the silver to the fibers, and at the same time the antimicrobial compound can be applied as an adhesion promoter.

[0012] In another embodiment, the manganese(IV) oxide is arranged at least section by section on the silver. This can be advantageously achieved using the methods according to the invention.

[0013] In another embodiment, the metallic silver has a mass ratio of 200:1 to 10:1 with respect to the manganese(IV) oxide. It has been shown that only very small amounts of manganese oxide are necessary with respect to the silver to achieve a significantly improved antiviral and antimicrobial effect.

[0014] In another embodiment, the manganese(IV) oxide has a mass fraction of 0.01 to 0.5 wt% with respect to the fibers. It has been shown that only a very small proportion of manganese dioxide is necessary, even with respect to the fibers.

[0015] In another embodiment, the metallic silver has a mass fraction of 0.1 to 5 wt.% relative to the fibers. Compared to known silver-coated materials, the silver content can be advantageously kept particularly low, since the manganese dioxide content leads to a significantly increased reactivity.

[0016] In another embodiment, the fibers have at least a partial coating with metallic silver and the silver is doped with manganese (IV) oxide.

[0017] In another embodiment, the fiber material is formed as a nonwoven fabric. Spunbond nonwovens made of polypropylene, for example, are well suited for this purpose. Other plastic nonwovens are equally suitable and can be readily coated.

[0018] The problem is further solved by a filter comprising a filter layer made of the fiber material according to the invention. The filter is preferably gas-permeable and may include further filter layers. For example, the filter layer made of the fiber material according to the invention can be embedded in further filter layers, such as an activated carbon filter, and filter layers for filtering coarse dirt. In this way, in addition to its antibacterial and antiviral properties, the filter can easily be supplemented with further layers offering additional filtering properties.

[0019] The problem is further solved by a face mask, in particular a surgical mask, which has a layer comprising a fiber material according to the invention. In other words, the face mask comprises at least one fiber material according to the invention. The layer preferably consists entirely of the fiber material. The layer, i.e., the fiber material, is arranged such that the wearer's breathing air flows through the layer during inhalation and / or exhalation. Thus, even with extremely long wearing times and the associated high saturation of the face mask with respiratory moisture, significantly improved protection of the wearer against bacteria and viruses can be ensured. Furthermore, third parties can also be protected from bacteria and viruses emitted by the wearer, as these are destroyed within the mask during exhalation.

[0020] In another embodiment, the face mask has an inner layer and an outer layer. The filter layer is positioned between the inner and outer layers. This allows the filter layer to be optimized for maximum antiviral effectiveness, while the inner and outer layers can fulfill other functions.

[0021] In another embodiment, the face mask has a water-repellent, e.g., hydrophobic, outer layer that is permeable to breathing air. Preferably, the outer layer is designed as a liquid-repellent nonwoven fabric, so that potentially infectious droplets do not even reach the filter layer. It is also conceivable that the filter layer according to the invention has an outer layer that is coated with a hydrophobic material. Additionally or alternatively, the face mask has an inner layer that faces the mouth area of ​​the wearer and is preferably designed as a skin-friendly nonwoven fabric, e.g., a polypropylene nonwoven fabric. This layered structure is particularly advantageous when the masks are manufactured on a large industrial scale and used in professional settings.

[0022] Since bacteria and viruses in the air are killed, the antibacterial and antiviral fiber mats made from the fiber material according to the invention can be advantageously used as respiratory masks or in face masks for both infected and non-infected persons. The longer protective effect can prevent shortages in hospitals and care facilities. The fiber mats can be used in all types of filters, for example, in special air purification filters for portable respiratory protective devices, where the air purification filters need to be replaced. Application in air conditioning systems for filtering humid indoor air in buildings and vehicles is also conceivable. In clinical settings, examination equipment and ventilators can be improved by using the filters according to the invention.

[0023] The problem is further solved by an insert for use with a conventional face mask. The insert is designed so that it can be placed inside or glued onto an existing face mask. The insert has a filter layer comprising a fiber material according to the invention and can be arranged so that inhalation and / or exhalation are possible through the insert. The insert has the advantage that only the filter layer needs to be manufactured, thus enabling existing masks, even in large quantities, to be equipped quickly and easily.

[0024] The problem is further solved by a respiratory mask comprising at least one filter according to the invention. The filter or filter layer can be integrated into a respiratory filter. The filter can also have additional CBRN protection functions.

[0025] An initial amount of manganese(II) nitrate or manganese(II) acetate and an initial amount of potassium permanganate solution can be applied to the provided raw fiber material to form manganese(IV) oxide on the raw fiber material (2). It has been found that this method significantly improves the coating of polymer nonwovens, such as polypropylene or polyethylene, which exhibit hydrophobic properties. The initial, very small amount of manganese(IV) oxide has been shown to considerably reduce the hydrophobic properties, thus enabling better silver coating. The adhesion strength of the resulting coating, i.e., the adhesion of the precipitate to the fiber material, is also significantly improved. The solutions used can preferably be applied simultaneously, e.g., via suitable nozzle systems.

[0026] Particularly after the initial application of manganese(IV) oxide, a solution containing silver ions and a reducing agent for reducing the silver ions to metallic silver can be applied to the raw fiber material. The reducing agent and the solution containing silver ions can preferably be applied simultaneously, e.g., via a suitable nozzle system.

[0027] In a subsequent step, a second quantity of manganese(II) nitrate or manganese(II) acetate and a second quantity of potassium permanganate solution are applied to the raw fiber material, which is already coated with silver, to form manganese(IV) oxide. The second quantity is larger than the first, in particular by a factor of 5 or more. The first quantity serves to reduce hydrophobicity and is advantageously already part of the antimicrobially active precipitate.

[0028] A process for producing a fiber material for antibacterial and / or antiviral use comprises the following steps, which can be carried out, for example, in the following order: Providing a raw fiber material, applying a solution containing silver ions to the raw fiber material, applying a reducing agent to reduce the silver ions to metallic silver on the raw fiber material (2), applying a potassium permanganate solution to the raw fiber material and applying manganese(II) nitrate or manganese(II) acetate, each of which is e.g. in basic solution, to form manganese(IV) oxide from the potassium permanganate solution on the raw fiber material.

[0029] The solution containing silver ions can be a silver salt solution. The process can be advantageously carried out on sheets of fiber material, for example, by first applying the metallic silver and then the manganese(IV) oxide in a production line. The major advantage is that the sheets can be sprayed at high speed through nozzles, thus enabling the production of large quantities of fiber material.

[0030] It has been shown that the process results in very good adhesion of the silver to the fiber material and, in particular, also of the manganese(IV) oxide to the fiber material. This is what makes it possible to use the fiber material in breathing air filters.

[0031] A process for producing a fiber material for antibacterial and / or antiviral use can be carried out as an alternative or supplement to the preceding process. The process comprises the following steps: Providing an electrically conductive raw fiber material, providing a direct current, wherein the raw fiber material is connected as the cathode, i.e., to the negative terminal of a direct current source, applying a solution containing silver ions to the raw fiber material, in particular through a nozzle having an anode made of a Ti / Pt wire or a Ti / Pt grid, wherein the anode is connected to the positive terminal of the direct current source, electrochemically depositing metallic silver onto the raw fiber material from the solution, applying a potassium permanganate solution and applying manganese(II) nitrate or manganese(II) acetate, each of which is e.g. in basic solution, to form manganese(IV) oxide from the potassium permanganate solution.

[0032] The invention will now be described and explained in more detail with reference to the exemplary embodiments shown in the figures. The figures show: FIG 1 a method for producing a fiber material according to the invention, FIG 2 an alternative or supplementary method for producing a fiber material according to the invention, FIG 3 a mouth and nose protection with the fiber material according to the invention as a filter.

[0033] FIG 1 shows a spraying technique for producing a coated fiber material 1, which is shown on a schematically depicted roll on the right side of the FIG 1 is rolled up. A water-soluble silver salt solution (e.g., silver nitrate or silver acetate) is sprayed via a first nozzle D1 onto a raw fiber material 2, which is wound in strips from a schematically depicted roller on the left side of the FIG 1 A reducing agent (e.g., sodium hypophosphite or organic reducing agents such as aldoses, e.g., glucose) is provided. A second nozzle, D2, sprays a reducing agent (e.g., sodium hypophosphite or organic reducing agents such as aldoses, e.g., glucose) onto the raw fiber material 2. The reducing agent serves to reduce the silver ions to metallic silver. The individual spraying processes of nozzles D1 and D2 can act on the raw fiber material 2 simultaneously or sequentially, e.g., at predetermined cycle times.

[0034] After the raw fiber material 2 is sprayed with the silver salt solution and the reducing agent, manganese(IV) oxide – also known as pyrolusite – is deposited onto the now metallically silver-coated raw fiber material 2. For this purpose, potassium permanganate solution is injected through a third nozzle D3, and manganese(II) nitrate or manganese(II) acetate, each in a basic solution, is injected through a fourth nozzle D4. Through comproportionation (a special case of a redox reaction), pyrolusite is produced from Mn+7 and Mn+2. To accelerate the chemical reaction, the fiber mat can be heated by a suitable heat source. The resulting bond between the fibers of fiber material 1 and the silver and pyrolusite is very well suited for the use of fiber material 2 in respiratory filters and face masks.

[0035] In FIG 2 A nozzle D1 is shown, which has an electrode made of a Ti / Pt wire or a Ti / Pt grid and is connected to a DC power source. In this embodiment, the metallic silver is deposited from the electrolyte solution via an electrochemical spray process. For this purpose, a raw fiber material 2E that is electrically conductive must be provided. Electrically conductive fiber material 2E is commercially available, for example, in the form of fiber mats. Alternatively, an electrically non-conductive raw fiber material 2 can be treated with special solutions that provide the electrically non-conductive raw fiber material 2 with an electrically conductive layer, thus making the raw fiber material 2 electrically conductive. Materials that occur as trace elements in living organisms and are non-toxic (e.g., Cu or Zn) are particularly advantageous here.The raw fiber material 2E serves primarily as the cathode and is therefore connected to the negative terminal of the DC power source. The Ti / Pt wire or the Ti / Pt grid in the first nozzle D1 serves as the anode, with the anode being connected to the positive terminal of the DC power source. This allows for alternative or supplementary use of... FIG 1 The silver is deposited electrochemically. This also achieves a very good bond with the fibers. Manganese dioxide (manganese(IV) oxide) is then added as in the spray method. FIG 1 described as being applied from a potassium permanganate and manganese (II) salt solution using nozzles D3 and D4.

[0036] FIG 3Figure 1 shows the head of a person 100 with a mouth and nose area 120. The mouth and nose area 120 is covered by a face mask 10. The face mask 10 has three layers: an outer layer 12, an inner layer 16, and a filter layer 14, which comprises a fiber material 1 coated according to the present invention. The layers 12, 14, and 16 can be welded together at the edges to ensure good adhesion. The face mask 10 typically has a fastening means that can be attached, for example, around the head of the person 100 or to the ears of the person 100. The resulting face mask 10 can be worn for longer than a comparable face mask from the prior art because moisture from the exhaled air provides an enhanced antiviral and antibacterial effect.

[0037] In summary, the invention relates to a fiber material for antibacterial and / or antiviral use that exhibits improved antibacterial and / or antiviral activity when moistened. The invention further relates to a filter, a face mask, an insert for a face mask, and a respirator.

Claims

1. Fibre material (1) for antibacterial and / or antiviral use, comprising fibres having - metallic silver and - manganese(IV) oxide, wherein the manganese(IV) oxide contacts the metallic silver at least in sections and wherein the manganese (IV) oxide and the metallic silver are present as particles larger than 10 µm.

2. Fibre material (1) according to Claim 1, having a surface composition, determined by means of an energy-dispersive X-ray spectroscopy on a scanning electron microscope: - 10% to 25%, in particular 14% to 20%, of silver, - 10% to 25%, in particular 16% to 19%, of manganese, wherein the manganese is in particular present as a manganese oxide.

3. Fibre material (1) according to either of the preceding claims, wherein at least parts of the manganese (IV) oxide are arranged at least in sections between the fibres and the silver.

4. Fibre material (1) according to any of the preceding claims, wherein the manganese (IV) oxide is arranged at least in sections on the silver.

5. Fibre material (1) according to any of the preceding claims, configured as a nonwoven.

6. Filter, in particular gas-permeable filter, having at least one filter layer (14) that has a fibre material (1) according to any of Claims 1 to 5.

7. Mouth / nose protector (10), in particular surgical mask, having a filter layer (14) that comprises a fibre material (1) according to any of Claims 1 to 5.

8. Mouth / nose protector (10) according to Claim 7, wherein the filter layer (14) is arranged between an inner layer (16) and an outer layer (12).

9. Mouth / nose protector (10) according to Claim 7 or 8, having a water-repellent outer layer preferably configured as a liquid-repellent nonwoven, and an inner layer (16) facing the mouth region of a wearer (100) of the mouth / nose protector (10) and preferably configured as a skin-compatible polypropylene nonwoven.

10. Insert for use with a mouth / nose protector (10), having a filter layer (14) that comprises a fibre material (1) according to any of Claims 1 to 5.

11. Respiratory protection mask having at least one filter according to Claim 6.