Self-sterilizing antiviral filter material, its production and use, and air filter device using the filter material

Abstract

The self-sterilizing antiviral filter material 10 comprises a breathable carrier 11 and a composite coating 12 bonded to the carrier 11, the composite coating 12 comprising at least one color pigment 13 having antiviral activity and an inorganic matrix material 14. The at least one color pigment 13 preferably comprises at least one compound from the phthalocyanine group. The matrix material is preferably selected from the group comprising metal oxides. Air filter devices comprising the self-sterilizing antiviral filter material, methods for making the filter material, and methods for inactivating viruses are also described.

Description

Technical Field

[0001] The present invention relates to a self-sterilizing antiviral filter material and an air filter device including such a filter material. In particular, the present invention relates to a filter material for an air purification device used, for example, for a breathing mask or an air conditioning system. The present invention also relates to a method for manufacturing a filter material and a method for inactivating a virus.

Background Art

[0002] When a virus is prevalent, it is known that it is very important to provide protection against infection and further spread of the virus by an appropriate air filter device. In addition to the filtering effect, the air filter device should also have, if possible, an antiviral and self-sterilizing effect. In particular, the wearing of a flexible breathing mask or filter is advisable or even necessary for personal protection. However, conventional filter materials known in practice do not have an antiviral effect or have only a weak antiviral effect.

[0003] An advantageous method that does not involve biocides to achieve an antiviral effect is to use a dye that sensitizes the formation of highly reactive bactericidal singlet oxygen through visible light and atmospheric oxygen (in its natural ground state as triplet oxygen), which is already used in medicine as so-called photodynamic therapy (PDT) for treating cancer. Phthalocyanine is particularly interesting as a sensitizing dye suitable for use in filter materials due to its broad absorption in the visible spectral range, high light stability, and high quantum yield for singlet oxygen generation (see, for example, International Publication No. 2015 / 154543). However, in the use of phthalocyanine in filter materials, the following problems have occurred so far.

[0004] First, unsubstituted phthalocyanine is an insoluble pigment in conventional solvents, making it impossible to coat a carrier from a solution.

[0005] Second, the introduction of solubilizing cationic ammonium groups into phthalocyanines for the production of three-dimensional mask filters as described in WO 2015 / 154543 has the drawback that, in addition to being very complex to synthesize, the diffusion of water-soluble dyes is slow ("bleeding") in the presence of humid (breathing) air. The same is largely true for the use of phthalocyanines containing solubilizing anionic sulfonic acid or carboxylic acid groups, as described in WO 2017 / 196961.

[0006] Third, the grafting of phthalocyanine dyes containing reactive groups to form chemical bonds with a support requires advanced processes and synthetic efforts and only allows the limited use of special supports having suitable docking sites (WO 2007 / 194843).

[0007] Finally, the incorporation of metal phthalocyanines into polymers (see WO 2012 / 064894) allows in principle coatings without diffusion, but only the dye molecules present on the polymer surface can react with atmospheric oxygen, so the singlet oxygen formation efficiency is very low.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0009] Accordingly, an object of the present invention is to provide an improved filter material having an antiviral effect that avoids the drawbacks of conventional filter materials. In particular, the antiviral filter material should be easy to manufacture by applying an antiviral component to different carriers, have high mechanical stability and light stability over a long period of time, self-disinfect efficiently under indoor conditions (atmospheric oxygen, sunlight or indoor light), and / or be suitable for use in air filter devices, particularly personal masks or indoor air purification equipment. A further object of the present invention is to provide a corresponding improved air filter device that comprises a filter material and avoids the drawbacks of conventional air filter devices. Another object of the present invention consists of providing an improved method for manufacturing the filter material and an improved method for inactivating, particularly destroying, viruses.

Means for Solving the Problems

[0010] These objects are each solved by a filter material, an air filter device, a method for manufacturing the filter material, and a method for inactivating viruses having the features of the independent claims. Preferred embodiments and uses of the present invention are described in the dependent claims.

[0011] According to a first general aspect of the present invention, the object is solved by a self-sterilizing antiviral filter material having a breathable carrier and a composite coating bonded to the carrier, the composite coating comprising at least one colored pigment having antiviral activity and an inorganic matrix material.

[0012] According to a second general aspect of the present invention, the object is solved by an air filter device, particularly a respiratory mask or an indoor air filter, comprising the filter material according to the first general aspect of the present invention.

[0013] According to a third general aspect of the present invention, this object is solved by one of the methods or embodiments for manufacturing a filter medium according to the present invention, the method comprising at least the following steps. A carrier is provided. The carrier is coated with at least one coloring pigment and a matrix material. The coating is applied, for example, by deposition under high vacuum. During deposition from the gas phase, at least one coloring pigment and the matrix material can be deposited on the carrier simultaneously (mixed vapor deposition, composite formation) or sequentially (layered composite formation).

[0014] According to a fourth general aspect of the present invention, this object is solved by a method for inactivating viruses, wherein a self - sterilizing antiviral filter medium according to the present invention or one of the embodiments is brought into contact with a virus or virus - containing substance in the presence of visible light.

[0015] The filter medium according to the present invention and an air filter device comprising the filter medium advantageously change (inactivate) virus particles to a non - infectious state, in particular denature or destroy them, when they come into contact with virus particles entering onto and / or into the filter medium from, for example, air and / or aerosols in the air, by the antiviral reaction effect of the coloring pigment. Thus, the filter medium according to the present invention is characterized by self - sterilization and sterilization of the air passing through the filter medium. The term "sterilization" refers to the transition of all virus particles to a non - infectious state or the transition of most of the virus particles such that the treated air is non - infectious when inhaled.

[0016] The inorganic matrix material used according to the present invention has certain advantages for fixing at least one coloring pigment and performs three important tasks: enhancing adhesion to the carrier, improving mechanical stability, and enhancing the activity of the antiviral component. The increase in activity can be based, for example, on an increase in the efficiency of singlet oxygen formation due to the decomposition of at least one coloring pigment (decomposition of the coloring pigment matrix) which mainly results in a molecular photoactive state.

[0017] Complex syntheses for fixing at least one coloring pigment and outward diffusion of at least one coloring pigment can be avoided. Formation of a chemical bond between at least one coloring pigment and a carrier is possible but not essential. Thus, limitation to a specific carrier can be avoided. In contrast to polymer embedding, the inorganic matrix material allows an increase in singlet oxygen formation efficiency because the dye molecules encapsulated in the inorganic matrix material can also come into contact with atmospheric oxygen.

[0018] As used herein, the term "coloring pigment" means a colorant, i.e., a coloring substance (dye molecule) that absorbs light in the visible range of the electromagnetic spectrum and contains particles that are essentially insoluble in their respective liquid application medium or ambient environment, or under the conditions of use, as opposed to soluble dyes.

[0019] The coloring pigments having antiviral activity used according to the present invention are preferably coloring pigments that can react in the presence of exposure to light and atmospheric oxygen (in the triplet state) to form singlet oxygen. The photochemical formation of singlet oxygen particularly preferably occurs upon exposure to visible light having a wavelength in the range of 400 nm to 750 nm. Singlet oxygen advantageously forms a powerful oxidant by which virus particles are denatured or destroyed.

[0020] Reactive singlet oxygen is known to be able to kill viruses (see "J. Photochem. Photobiol." 36 (1996) 23 by A. Dewilde). Thus, the formation of singlet oxygen enables continuous self-sterilization of the filter material according to the present invention in air and sunlight or artificial light, and sterilization of the air passing through the filter material.

[0021] Light is advantageously provided by ambient light when the breathing mask is being worn. The air filter device comprising the filter material may also be configured to expose the filter material to ambient light and / or may comprise an illumination device, for example based on light emitting diodes, adapted to expose the filter material to light.

[0022] In a preferred embodiment, at least one coloring pigment comprises at least one compound from the group of phthalocyanines, which group includes, in particular, unsubstituted phthalocyanines, substituted phthalocyanine derivatives and their complexes, in particular metal complexes. Particularly preferred is the unsubstituted phthalocyanine itself (C 32H H 18 N 8 ), or a metal-phthalocyanine complex particularly selected from the group comprising ZnPc, ClAlPc, FePc, NiPc, CoPc, and CuPc (where Pc represents phthalocyanine). The phthalocyanine compounds used according to the present invention are typically water-insoluble and unsubstituted. However, it is also possible to use substituted phthalocyanines which are preferably also water-insoluble. Advantageously, the coloring pigments used according to the present invention are characterized by a particularly high yield of singlet oxygen formation.

[0023] In a particularly preferred embodiment, ZnPc or ClAlPc is used as the metal phthalocyanine for the composite coating by high vacuum evaporation, and the layer thickness preferably varies between 20 nm and 500 nm.

[0024] The term "inorganic matrix material" generally refers to any inorganic compound that is at least partially transparent in the visible range of the electromagnetic spectrum.

[0025] According to a preferred embodiment, the inorganic matrix material is selected from the group comprising metal oxides (including silicon dioxide), and particularly preferably, SiO 2 , TiO 2 , ZnO, MoO 3 , and mixtures thereof (mixtures of at least two of these compounds). These matrix materials can be fabricated, deposited on a carrier, and used in a compact or nanoporous form, and the nanoporous form is preferred for certain embodiments.

[0026] The composite coating of the coloring pigment and the matrix material is preferably at least one thin layer, particularly a layer having a thickness in the range of 10 nm to 1000 nm. The proportion of the coloring pigment in the matrix material is typically in the range of 1 to 50% by volume based on the matrix material.

[0027] The composite coating is disposed on a breathable carrier. The term "breathable carrier" is generally used to describe any material that houses the composite coating and through which air can flow, particularly a structure having pores or holes. Advantageously, the carrier remains breathable even when receiving the composite coating, and the composite coating is supported by the structure without sealing the carrier. As a result, the filter material is breathable. The carrier can include an integral material such as a layer, piece, or sheet, and / or particulate matter in a suitable holder or a plurality of materials such as a plurality of layers, pieces, or sheets.

[0028] The composite is preferably used as a coating on a carrier, and these are deposited on the carrier by vapor deposition of phthalocyanine, particularly metal phthalocyanine, especially multi-source vapor deposition. Together, at least one metal oxide is applied simultaneously or continuously under high vacuum, and subsequent annealing advantageously improves the adhesion. The annealing conditions can vary depending on each composite material, but can be easily determined by those skilled in the art using routine tests. For example, annealing can be performed at a temperature in the range of 50 °C to 200 °C for a time in the range of 10 minutes to 5 hours.

[0029] In a further particularly advantageous embodiment, SiO 2 , TiO 2 , or MoO 3 is used as the metal oxide for the composite coating by high vacuum vapor deposition. MoO 3 can advantageously be deposited simply by thermal vapor deposition, for example by resistance heating in high vacuum, while SiO 2 and TiO 2can be deposited at a higher temperature and thus can typically be deposited by electron beam evaporation (e.g., as described in Adv. Mat. (1996) 93 - 97 by Jaeger et al.) or sputtering.

[0030] Another advantage of the present invention is that various materials are available and are suitable for providing a breathable carrier. The carrier preferably comprises at least one layer of a layered or sheet-like material selected from the group consisting of woven fabric, non-woven fabric, breathable plastic, paper, particularly filter paper, cardboard, organic porous material, and inorganic porous material.

[0031] The filter material according to the present invention is characterized in that the carrier having a composite coating is preferably breathable, particularly suitable for breathing through the filter material, and / or the carrier having a composite coating is flexibly deformable.

[0032] The filter material according to the present invention can be used in a freely selectable form as an antiviral active material in a respiratory mask or in an antibacterial air filter.

[0033] The filter material according to the present invention is advantageously suitable for a method of destroying viruses, and the filter material is brought into contact with a virus or a virus-containing substance, such as an air-containing virus or a virus-containing substance. If the coloring pigment having antiviral activity of the filter material according to the present invention is a coloring pigment that reacts in the presence of light and oxygen to form singlet oxygen, such contact in such a method is thus carried out in the presence of light and oxygen.

[0034] Further details and advantages of the present invention are described with reference to the accompanying drawings.

Brief Description of the Drawings

[0035]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0036] In a specific embodiment, the layer of the filter material 10 of a conventional respirator mask (see FIG. 1, not to scale) is provided as a carrier 11, and on the carrier 11, a composite coating 12 having a coloring pigment 13, such as ZnPc, and a matrix material 14, such as SiO 2 and, is applied in an equal volume ratio with a layer thickness of, for example, 300 nm. The filter material 10 is adapted to a specific application by cutting it to the size and shape of a filter receptacle of an air filter device, such as within a respirator mask 21 (see FIG. 2) or an air purification device 22 (see FIG. 3).

[0037] When the air filter device is used, the virus is inactivated by the fact that air is drawn through the exposed filter material 10, spread over the composite coating, and passed through the composite coating. The air is transported, for example, by the inhalation pressure on the respirator mask 21 or by the pump device of the air purification device 22.

[0038] The features of the present invention disclosed in the foregoing description, drawings, and claims may be important, both individually and in combinations or sub - combinations, for realizing the present invention in various embodiments.

Claims

1. A breathable carrier (11), a composite coating (12) bonded to the carrier, the composite coating (12) comprising at least one coloring pigment (13) having antiviral activity and an inorganic matrix material (14), and The matrix material (14) is TiO ２ , ZnO, MoO ３ and mixtures thereof; the at least one coloring pigment (13) includes at least one compound from the group of phthalocyanines, and the composite coating (12) is a multilayered vapor deposition layer of at least one compound from the group of phthalocyanines and the matrix material (14), or a vapor deposition layer in which at least one compound from the group of phthalocyanines and the matrix material (14) are in a mixed state, a self - sterilizing antiviral filter material (10).

2. The at least one coloring pigment (13) is at least one compound from the group including ZnPc, ClAlPc, FePc, NiPc, CoPc, CuPc, and C ３２ H １８ N ８ and is at least one compound from the group including The filter material according to Claim 1.

3. The carrier (11) includes at least one material selected from the group consisting of woven fabric, non - woven fabric, breathable plastic, paper, cardboard, organic porous material, and inorganic porous material, The filter material according to Claim 1 or 2.

4. The carrier (11) having the composite coating is breathable, The filter material according to any one of Claims 1 to 3.

5. The carrier (11) having the composite coating is flexibly deformable, The filter material according to any one of Claims 1 to 4.

6. An air filter device comprising the self - sterilizing antiviral filter material according to any one of Claims 1 to 5.

7. A respiratory mask (21) or an air purification device (22), particularly an air filter of an air - conditioning system, comprising the air filter device according to Claim 6.

8. A method for manufacturing the filter material (10) according to any one of Claims 1 to 5, comprising providing the breathable carrier (11), and coating the carrier (11) with the at least one coloring pigment (13) and the inorganic matrix material (14), wherein the step of coating the carrier (11) is realized by the deposition of the at least one coloring pigment (13) and the matrix material (14) from the gas phase under high vacuum.

9.

10. ​ ​ The deposition according to claim 8, comprising a colored pigment deposition and a subsequent matrix material deposition. **Claim 11** The method according to any one of claims 8 to 10, wherein after deposition of the at least one colored pigment (13) and the matrix material (14), the deposited material is annealed. **Claim 12** A method for inactivating a virus, wherein the self - sterilizing antiviral filter medium (10) according to any one of claims 1 to 5 is brought into contact with a virus or a virus - containing substance. **Claim 13** The method according to claim 12, wherein the contact is carried out in the presence of light and oxygen.

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