Antibacterial and antiviral paper

Abstract

To provide antibacterial and antiviral paper using a new type of inorganic material for imparting antibacterial and antiviral properties.SOLUTION: The antibacterial / antiviral paper of the present invention is antibacterial / antiviral paper containing antibacterial / antiviral ceramic particles containing a La-Mo-based composite oxide and / or a Ce-Mo-based composite oxide as a main component, and organic fibers, wherein an average fiber diameter of the organic fibers is larger than an average particle diameter of the ceramic particles, the antibacterial / antiviral paper contains fine fibers having a fiber diameter smaller than the average particle diameter, and the fine fibers hold the ceramic particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to antibacterial and antiviral paper. [Background technology]

[0002] As shown in Patent Document 1, a technology for imparting antibacterial and antiviral properties to paper is known. In recent years, due to the spread of infectious diseases and increased awareness of cleanliness, there has been a demand for further improvement in the performance of various antibacterial and antiviral products. Therefore, there is also a demand for improved antibacterial and antiviral performance in paper. Conventionally, organic or inorganic (metallic) antibacterial and antiviral components have been used to impart antibacterial and antiviral properties to paper.

[0003] Incidentally, as shown in Patent Document 2, composite oxides containing rare earth elements and molybdenum (Mo) and the like (rare earth molybdenum composite oxides) are known as new types of inorganic materials with antibacterial and antiviral properties. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-83167 [Patent Document 2] International Publication No. 2020 / 017493 Summary of the Invention [Problem to be solved by the invention]

[0005] Organic antibacterial and antiviral ingredients are prone to volatilization and disappearance over time or due to changes in the environment. Inorganic (metallic) antibacterial and antiviral ingredients are prone to discoloration and performance degradation over time. The above-mentioned antibacterial and antiviral ingredients used in paper have an average particle size of several tens of microns, which is bulkier and larger than the fibers that make up paper, raising concerns about the ability of paper to retain the antibacterial and antiviral ingredients.

[0006] Furthermore, conventionally, the rare earth molybdenum composite oxides described above have been water-repellent and have not been used to impart antibacterial or antiviral properties to paper.

[0007] The object of the present invention is to provide antibacterial and antiviral paper that uses ceramic particles whose main component is a rare earth molybdenum composite oxide to impart antibacterial and antiviral properties. [Means for solving the problem]

[0008] The means for solving the above problems are as follows: <1> An antibacterial and antiviral paper comprising antibacterial and antiviral ceramic particles whose main components are La-Mo based composite oxide and / or Ce-Mo based composite oxide, and organic fibers, wherein the organic fibers have an average fiber diameter larger than the average particle diameter of the ceramic particles, and the paper contains fine fibers whose fiber diameters are smaller than the average particle diameter, and the fine fibers hold the ceramic particles.

[0009] <2> The organic fiber is a fiber that is not a fibrillar fiber. <1> Antibacterial and antiviral paper described in.

[0010] <3> The fine fibers are fibrillar fibers. <1> or <2> Antibacterial and antiviral paper described in.

[0011] <4> The average fiber diameter of the organic fibers is 2 μm or more and 100 μm or less. <1> from <3> 1. Antibacterial and antiviral paper according to any one of the preceding items.

[0012] <5> The fiber diameter of the fine fibers is 0.05 μm or more. <1> from <4> 1. Antibacterial and antiviral paper according to any one of the preceding items.

[0013] <6> Basis weight: 30g / m 2 More than 200g / m 2The above <1> from <5> 1. Antibacterial and antiviral paper according to any one of the preceding items.

[0014] <7> The content of the ceramic particles is 5% by mass or more and 80% by mass or less. <1> from <6> 1. Antibacterial and antiviral paper according to any one of the preceding items.

[0015] <8> The La-Mo based composite oxide is La2Mo2O9, and the Ce-Mo based composite oxide is Ce5(MoO4)8. <1> from <7> 1. Antibacterial and antiviral paper according to any one of the preceding items. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide antibacterial and antiviral paper that uses ceramic particles whose main component is a rare earth molybdenum composite oxide to impart antibacterial and antiviral properties. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 shows an SEM image of the antibacterial and antiviral paper of Example 1. [Figure 2] FIG. 1 shows an SEM image of the antibacterial and antiviral paper of Example 2. [Figure 3] 1 shows an SEM image of paper from Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0018] [Antibacterial and antiviral paper] The antibacterial and antiviral paper of this embodiment contains antibacterial and antiviral ceramic particles whose main components are La-Mo based composite oxide and / or Ce-Mo based composite oxide, organic fibers, and fine fibers.

[0019] The ceramic particles have antibacterial and / or antiviral properties. In this specification, antibacterial and / or antiviral properties refer to either or both of antibacterial and antiviral properties. In this specification, antibacterial and / or antiviral properties are referred to as antibacterial and antiviral properties. In this specification, paper having antibacterial and / or antiviral properties is referred to as "antibacterial and antiviral paper."

[0020] The ceramic particles are mainly composed of La-Mo composite oxide and / or Ce-Mo composite oxide. In this specification, La-Mo composite oxide and / or Ce-Mo composite oxide refers to either or both of La-Mo composite oxide and Ce-Mo composite oxide. In this specification, La-Mo composite oxide and Ce-Mo composite oxide are collectively referred to as rare earth molybdenum composite oxide.

[0021] In this specification, the expression "mainly composed of La-Mo composite oxide and / or Ce-Mo composite oxide" means that the ceramic particles contain 50% by mass or more (preferably 70% by mass or more, more preferably 85% by mass or more, and particularly preferably 95% by mass or more) of La-Mo composite oxide and / or Ce-Mo composite oxide. The La-Mo composite oxide and / or Ce-Mo composite oxide is used in the form of particles (powder) as the ceramic particles.

[0022] The La-Mo composite oxide is a composite oxide containing lanthanum (La) and molybdenum (Mo) (lanthanum-molybdenum composite oxide). La2Mo2O9 is preferred as the La-Mo composite oxide. The La-Mo composite oxide may consist solely of La2Mo2O9, or may contain lanthanum-molybdenum composite oxides other than La2Mo2O9.

[0023] Examples of lanthanum-molybdenum composite oxides other than La2Mo2O9 include La2Mo3O 12 , La6MoO 12, La7Mo7O 30 , La2Mo4O 15 , La2MoO6, La4MoO9 and LaMo2O5.

[0024] The Ce-Mo composite oxide is a composite oxide containing cerium (Ce) and molybdenum (Mo) (cerium-molybdenum composite oxide). There are no particular limitations on the Ce-Mo composite oxide as long as it does not impair the object of the present invention. For example, Ce2Mo3O 13 , Ce(MoO4)2, Ce2MoO6, Ce2(MoO4)3, Ce2Mo4O 15 , Ce5(MoO4)8, Ce6(MoO4)8(Mo2O7), Ce8Mo 12 O 49 These may be used alone or in combination of two or more. As the Ce-Mo based composite oxide, Ce5(MoO4)8 is preferred.

[0025] Rare earth molybdenum composite oxides such as La-Mo composite oxides can be identified by analyzing the X-ray diffraction spectrum obtained by powder X-ray diffraction (for example, by comparing with known X-ray diffraction spectrum data).

[0026] The rare earth molybdenum composite oxide is produced, for example, through a preparation step and a first firing step. Here, the case of producing a powder of a La-Mo composite oxide is illustrated.

[0027] The preparation step is a step of mixing a lanthanum compound and a molybdenum compound to prepare a mixed powder.

[0028] The lanthanum compound is a compound containing lanthanum (La), which is necessary for producing a La-Mo based composite oxide, and examples thereof include La(OH)3, La2O3, and La2(CO3)3. As the lanthanum compound, for example, at least one selected from the group consisting of La(OH)3, La2O3, and La2(CO3)3 may be used. Note that La(OH)3 is preferred as the lanthanum compound.

[0029] The molybdenum compound is a compound containing molybdenum (Mo) necessary for producing a La-Mo based composite oxide, and examples thereof include MoO3, MoO2, MoO, Mo(OH)3, and Mo(OH)5. As the molybdenum compound, for example, at least one selected from the group consisting of MoO3, MoO2, MoO, Mo(OH)3, and Mo(OH)5 may be used. Note that MoO3 is preferred as the molybdenum compound.

[0030] The mixing ratio of the lanthanum compound and the molybdenum compound is not particularly limited as long as it does not impair the object of the present invention, but it is preferable to adjust it so that the molar ratio is La:Mo=1:1, for example.

[0031] The lanthanum compound and the molybdenum compound are both powders, and they may be mixed together in the powder state, or a solvent such as a lower alcohol (e.g., ethanol) may be added to the powders to perform wet mixing. The lanthanum compound and the molybdenum compound may be mixed by wet mixing using, for example, alumina balls (alumina boulders). The wet-mixed mixture is then dried as appropriate by water bath drying, spray drying, or the like. A mixed powder of the lanthanum compound and the molybdenum compound is obtained by such a preparation process.

[0032] The first firing step is a step of firing the mixed powder obtained in the preparation step to react the lanthanum compound and the molybdenum compound in the mixed powder. In the first firing step, the mixed powder is fired, for example, at a temperature of 500°C to 700°C for 2 hours or more. The first firing step is carried out under normal atmospheric pressure.

[0033] In this first firing step, the lanthanum compound and the molybdenum compound in the mixed powder react with each other to obtain a La-Mo based composite oxide containing La2Mo2O9 and the like.

[0034] The obtained La-Mo based composite oxide is processed into particles (powder) having an average particle size within a predetermined range by a pulverization step, if necessary.

[0035] The pulverization step is a step in which the La-Mo-based composite oxide after the first firing is pulverized using a media stirring pulverizer such as a bead mill to obtain a powdered La-Mo-based composite oxide. The pulverization time and other conditions are set appropriately. In this pulverization step, a powdered La-Mo-based composite oxide having an average particle size within a predetermined range may be prepared, or a powdered La-Mo-based composite oxide having an average particle size within a predetermined range may be prepared in a pulverization step after the second firing step described below. In this manner, a powder (particle) of the La-Mo-based composite oxide is obtained.

[0036] The obtained La-Mo composite oxide powder may be granulated as necessary. For example, a solvent such as ethanol is added to the La-Mo composite oxide powder, and the mixture is wet-mixed and pulverized using alumina balls or the like to prepare a slurry. The dried slurry is then passed through a sieve with a specified mesh size to obtain a La-Mo composite oxide powder granulated to a specified size.

[0037] Furthermore, as long as the object of the present invention is not impaired, the granulated La-Mo composite oxide may be sintered, and the resulting sintered body may then be pulverized to obtain a pulverized product, which may then be used as ceramic particles. The sintered body may be obtained, for example, by molding the La-Mo composite oxide powder before sintering into a predetermined shape and firing the resulting molded body under a predetermined temperature condition (e.g., 900°C or higher). In this specification, the firing step performed to sinter the La-Mo composite oxide is referred to as the "second firing step." This second firing step can be performed in an air atmosphere.

[0038] The La—Mo based composite oxide obtained after the second firing step may be adjusted to particles (powder) having an average particle size within a predetermined range by a pulverization step, if necessary.

[0039] Furthermore, when producing a Ce-Mo based composite oxide powder, a cerium compound and a molybdenum compound are mixed in the preparation step to prepare a mixed powder. Examples of cerium compounds include CeO2, cerium nitrate, cerium chloride, cerium sulfate, cerium hydroxide, cerium carbonate, and cerium acetate. CeO2 is preferred as the cerium compound. The same molybdenum compound as used in producing the La-Mo based composite oxide powder is used.

[0040] The mixing ratio of the cerium compound and the molybdenum compound is not particularly limited as long as it does not impair the object of the present invention, but it is preferable to adjust the mixing ratio so that, for example, the molar ratio is Ce:Mo=5:8.

[0041] When producing the powder of Ce-Mo based composite oxide, the steps such as the first firing step and the pulverization step are carried out in the same manner as when producing the powder of La-Mo based composite oxide described above.

[0042] Rare earth molybdenum composite oxides exhibit antibacterial and antiviral properties both in the powder state before sintering and in the powder state after sintering.

[0043] Rare earth molybdenum composite oxides exhibit antibacterial properties against Staphylococcus aureus (gram-positive bacteria), Escherichia coli (gram-negative bacteria), etc. Furthermore, rare earth molybdenum composite oxides are presumed to exhibit antibacterial properties against Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, multidrug-resistant Pseudomonas aeruginosa, etc.

[0044] Furthermore, rare earth molybdenum composite oxides exhibit antiviral properties against bacteriophage Qβ, bacteriophage φ6, etc. Bacteriophage Qβ is an envelopeless virus known as a surrogate for norovirus, while bacteriophage φ6 has an envelope and is known as a surrogate for influenza virus. Furthermore, rare earth molybdenum composite oxides are presumed to exhibit antiviral properties against feline calicivirus (a surrogate for human norovirus), human influenza virus, hog cholera virus, bovine viral diarrhea virus, border disease virus, kirchin petivirus, coronavirus, avian influenza virus, etc.

[0045] The average particle diameter of the ceramic particles is smaller than the average fiber diameter of organic fibers, which will be described later. The average particle diameter of the ceramic particles is larger than the average fiber diameter of fine fibers, which will be described later. The average particle diameter of such ceramic particles is not particularly limited as long as it does not impair the object of the present invention, and may be, for example, 0.01 μm or more and 50 μm or less. The lower limit of the average particle diameter is preferably 0.05 μm or more, more preferably 0.1 μm or more, and the upper limit of the average particle diameter is preferably 10 μm or less, more preferably 2 μm or less. The average particle diameter is determined as the particle diameter (D50) at which the cumulative frequency reaches 50%, as measured using a laser diffraction particle size distribution analyzer.

[0046] Organic fibers are fibers containing organic compounds. Fine fibers are fine fibers (i.e., fibers with an average fiber diameter smaller than a certain value). For example, fibers branching from thick fibers (trunks) are considered fine fibers. The average fiber diameter of fine fibers is smaller than the average fiber diameter of organic fibers. Fine fibers are fibers whose average fiber diameter is smaller than a certain value when observed in a vertical cross section of the sheet-like portion of antibacterial and antiviral paper (hereinafter sometimes referred to as the "sheet substrate"). In contrast, organic fibers are fibers whose fiber diameter exceeds the certain value and contain organic compounds. The certain value can be selected based on the constituent materials of the organic fibers and fine fibers, provided that the average fiber diameter of fine fibers is smaller than that of organic fibers. For example, a range of 2 μm to 100 μm is a guideline, and a range of 5 μm to 50 μm is preferable. For example, if the certain value is 5 μm, fibers with a fiber diameter of 5 μm or less can be considered fine fibers, and fibers with a fiber diameter of more than 5 μm and containing organic compounds can be considered organic fibers.

[0047] In this specification, the average fiber diameter of fibers means a diameter measured by the following method: The cross-sectional area of ​​the fibers is calculated based on a vertical cross section of the fibers photographed with a microscope (for example, using known software), and the diameter of a circle having the same area as the cross-sectional area is calculated. The average area diameter (for example, the average value of 20 fibers) is then determined as the average fiber diameter of the fibers.

[0048] The constituent material of the organic fiber can be appropriately selected from organic compounds, but preferred are fibers mainly containing polyethylene fibers, polypropylene fibers, polybutene fibers, nylon fibers, rayon fibers, cupra fibers, acetate fibers, polyvinyl chloride fibers, polyurethane fibers, polyparaphenylene benzobisoxazole fibers, polyamideimide fibers, polyimide fibers, polyarylate fibers, polyetherimide fibers, vinylon fibers, polycarbonate fibers, ethylene vinyl acetate fibers, ethylene vinyl alcohol fibers, polyphenylene sulfide fibers, polyester fibers (polyethylene terephthalate fibers, polybutylene terephthalate fibers, polyethylene naphthalate fibers, etc.), cellulose fibers such as wood pulp, and aramid fibers. Furthermore, as the constituent material of the organic fiber, fibers with a certain degree of strength are preferred, as they form the sheet substrate of antibacterial and antiviral paper.

[0049] In this embodiment, the average fiber diameter of the organic fibers is larger than the average particle diameter of the ceramic particles. For example, the average fiber diameter of the organic fibers is preferably 2 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

[0050] It is preferable that the organic fiber be a fiber that is not a fibrillar fiber. Here, fibrillar fiber means a fiber made of an organic material and having a fibrous microstructure with a size of several nm to several μm. Specific examples of fibrillar fibers include natural cellulose fiber, regenerated cellulose fiber, aramid fiber, acrylic fiber, polyarylate fiber, and polyethylene synthetic pulp. By using an organic fiber that is not a fibrillar fiber as a constituent material, the strength, breathability, etc. of the sheet substrate are ensured.

[0051] The constituent material of the fine fibers can be selected as appropriate, but is preferably a fibrillated natural fiber. Furthermore, the constituent material of the fine fibers is preferably a fiber with a certain degree of strength, from the viewpoint of being able to easily hold ceramic particles. Furthermore, the constituent material of the fine fibers is preferably capable of holding ceramic particles (i.e., has a certain degree of affinity) depending on the type of ceramic particles used. The constituent material of the fine fibers can be selected as appropriate depending on these purposes.

[0052] The average fiber diameter of the fine fibers is, for example, preferably 0.05 μm or more and 20 μm or less, and more preferably 0.1 μm or more and 10 μm or less, and is preferably 1 / 5 or less of the average fiber diameter of the organic fibers.

[0053] The fine fibers are preferably made of fibril fibers. For example, microfiber cellulose (MFC) can be used as the material for the fine fibers. When the fine fibers are made of fibril fibers, the ceramic particles are entangled in the fibril fibers and supported on the fibers.

[0054] In this embodiment, the ratio (mass ratio) of the content of organic fibers to fine fibers in the sheet-like substrate is not particularly limited as long as it does not impair the object of the present invention, but for example, it is preferable that the organic fibers:fine fibers ratio is 50:50 to 89:1.

[0055] The porosity of the antibacterial and antiviral paper is preferably 50 to 90%. When the antibacterial and antiviral paper has this porosity, the ceramic particles are sufficiently held in the fibers and breathability is not impaired.

[0056] The size (area, thickness) and shape of the antibacterial / antiviral paper are selected appropriately depending on the intended use of the antibacterial / antiviral paper. The thickness of the antibacterial / antiviral paper may be, for example, 0.03 mm or more and 0.5 mm or less.

[0057] The constituent materials of the organic fibers and / or fine fibers preferably contain a hydrophilic compound. This preferably causes the organic fibers and / or fine fibers to exhibit high hydrophilicity. When the organic fibers and / or fine fibers are hydrophilic, moisture that comes into contact with the antibacterial and antiviral paper is retained by the organic fibers and / or fine fibers. This action makes it easier for bacteria and viruses to be introduced into the ceramic particles of the antibacterial and antiviral paper when they use moisture as a medium, i.e., when bacteria and viruses are contained in moisture. This is particularly preferable for applications such as masks, where bacteria and viruses are introduced using moisture such as saliva or exhaled breath as a medium.

[0058] Either the organic fiber or the fine fiber may be a hydrophilic compound. Preferably, the fine fiber is a hydrophilic compound. In this embodiment, the fine fiber plays a major role in holding the ceramic particles, so if the fine fiber is a hydrophilic compound, when the fine fiber holds moisture, the ceramic particles and bacteria or viruses will easily come into contact with each other. It is more preferable that both the constituent materials of the organic fiber and the inorganic fiber are hydrophilic compounds. If both the constituent materials are hydrophilic compounds, bacteria and viruses will be more easily introduced into the ceramic particles.

[0059] The constituent material of the organic fibers and / or fine fibers is preferably a material having at least one functional group selected from a hydroxy group, a carboxy group, an amino group, and a sulfo group. That is, the hydrophilic compound is preferably a compound having at least one functional group selected from a hydroxy group, a carboxy group, an amino group, and a sulfo group. Materials having these functional groups are hydrophilic and can be particularly effective in the above-mentioned applications.

[0060] Specific examples of the constituent material made of the hydrophilic compound include cellulose, polyvinyl alcohol (PVA), starch, carboxymethyl cellulose (CMC), and materials having hydrophilic functional groups.

[0061] In this embodiment, the organic fibers and the fine fibers may be made of the same constituent material or different constituent materials. When both the organic fibers and the fine fibers are made of hydrophilic constituent materials, they may be made of the same constituent material.

[0062] In this embodiment, the organic fibers and / or fine fibers may be of a single type or of multiple types. For example, two types of organic fibers made of different constituent materials may be used. By using two types of organic fibers made of different constituent materials, a sheet substrate having superior mechanical properties such as strength can be obtained as a composite. Alternatively, two types of organic fibers made of different constituent materials each having two different properties may be used. For example, an organic fiber with excellent strength and an organic fiber with excellent affinity for fine fibers and ceramic particles may be selected and combined.

[0063] For example, organic fibers using PET (polyethylene terephthalate) as a constituent material can be used in combination with the above-mentioned hydrophilic constituent material (for example, organic fibers of PVA).

[0064] Antibacterial and antiviral paper may contain other components in addition to organic fibers, fine fibers, and ceramic particles. For example, it may contain powders of compounds similar to the organic fibers mentioned above, or binders. By including these, it is possible to improve the strength of the antibacterial and antiviral paper, improve its affinity with ceramic particles, and prevent particle shedding.

[0065] The mass per area of ​​the antibacterial and antiviral paper (so-called basis weight) is not particularly limited as long as it does not impair the object of the present invention. For example, 2 More than 200g / m 2 It is preferable that:

[0066] In addition, the content of ceramic particles in the antibacterial and antiviral paper is preferably 5% by mass or more and 80% by mass or less.

[0067] Antibacterial and antiviral paper can be produced, for example, using a wet papermaking method. For example, a slurry is prepared by dispersing cellulose fibers and ceramic particles in water. Fillers, dispersants, thickeners, antifoaming agents, paper strength agents, sizing agents, flocculants, colorants, and fixing agents may be added to this slurry as appropriate. Organic fibers made from thermoplastic resins such as polyethylene terephthalate (PET), polyvinyl alcohol (PVA), polyethylene, and polypropylene, as well as polyvinyl chloride resin, aramid resin, nylon, and acrylic resin, may also be added to the slurry. After preparing the slurry, the slurry is used for wet papermaking in a papermaking machine. Examples of papermaking machines that can be used include cylinder papermaking machines, Fourdrinier papermaking machines, short wire papermaking machines, tilt papermaking machines, and combination papermaking machines that combine the same or different types of papermaking machines. The antibacterial and antiviral paper of this embodiment can be obtained by dehydrating and drying the wet paper after papermaking using an air dryer, cylinder dryer, suction drum dryer, infrared dryer, or the like. [Example]

[0068] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples in any way.

[0069] [Preparation of La-Mo composite oxide] La(OH)3 was prepared as the lanthanum compound, and MoO3 was prepared as the molybdenum compound. Then, raw powders of the lanthanum compound and raw powders of the molybdenum compound were weighed out so that the molar ratio was 1:1 (La:Mo = 1:1). The weighed raw powders were mixed with a predetermined amount of ethanol, and the resulting wet mixture was dried to obtain a mixed powder. The mixed powder was then calcined in an air atmosphere at a temperature of 550°C for 10 hours to obtain a calcined powder (pre-calcined powder) consisting of a reaction product of the lanthanum compound and the molybdenum compound. The calcined powder thus obtained was then granulated by the following procedure.

[0070] The mixture was placed in a resin pot together with a predetermined amount of ethanol, and the mixture was subjected to wet mixing and grinding using alumina balls to obtain a slurry.

[0071] Thereafter, the obtained slurry was dried at a temperature of 80°C for about 2 hours, and the obtained dried product was passed through a sieve with an opening of 250 μm to obtain a La-Mo based composite oxide powder as a granulated powder.

[0072] The granulated La-Mo composite oxide powder was powder press-molded using a specified press (molding pressure: 98 MPa), and then cold isostatically pressed at a pressure of 150 MPa to obtain a disk-shaped compact. This compact was then fired in an air atmosphere at 900°C for 10 hours to obtain a sintered body. The resulting sintered body was coarsely crushed in a mortar and then wet-pulverized using alumina balls for 24 hours to obtain a La-Mo composite oxide powder composed of the crushed sintered body. The La-Mo composite oxide was identified as La2Mo2O9 from the X-ray diffraction spectrum obtained by powder X-ray diffraction.

[0073] The particle size of the obtained La-Mo composite oxide powder was determined as the volume-based average particle size (D50) by laser diffraction. Specifically, the average particle size (D50) of the La-Mo composite oxide powder was determined using a laser diffraction particle size distribution analyzer (model "LA-950", manufactured by Horiba, Ltd.). As a result, the average particle size was 1 μm.

[0074] [Preparation of Ce-Mo composite oxide] CeO2 was prepared as the cerium compound, and MoO3 was prepared as the molybdenum compound. Then, raw powders of the cerium compound and the molybdenum compound were weighed out so that the molar ratio was 5:8 (Ce:Mo = 5:8). The weighed raw powders were placed in a resin container (resin pot) and mixed for 24 hours using zirconia balls. The resulting wet mixture in a slurry state was dried in a water bath to obtain a mixed powder. The mixed powder was then calcined in an air atmosphere at 475°C for 1 hour to obtain a calcined powder (Ce-Mo composite oxide powder) consisting of a reaction product of the cerium compound and the molybdenum compound.

[0075] The mixture was placed in a resin pot together with a predetermined amount of ethanol, and the mixture was subjected to wet mixing and grinding using zirconia balls to obtain a slurry.

[0076] Thereafter, the obtained slurry was dried at a temperature condition of 80°C for about 2 hours, and the obtained dried product was passed through a sieve with an opening of 250 μm to obtain a Ce-Mo based composite oxide powder as a granulated powder.

[0077] The granulated Ce-Mo composite oxide powder was powder-pressed using a specified press (pressing pressure: 98 MPa) and then cold isostatically pressed at a pressure of 150 MPa to obtain a green body. The green body was then fired in an air atmosphere at 500°C for 10 hours to obtain a sintered body. The obtained sintered body was coarsely crushed in a mortar and then wet-pulverized using zirconia boulders for 24 hours to obtain a Ce-Mo composite oxide powder composed of the crushed sintered body. The Ce-Mo composite oxide was identified as Ce5(MoO4)8 from the X-ray diffraction spectrum obtained by powder X-ray diffraction. The obtained Ce-Mo composite oxide powder had an average particle size of 1 μm.

[0078] Example 1 La2Mo2O9 and Ce5(MoO4)8 were prepared as antibacterial and antiviral ceramic particles, wood pulp and acrylic fibers were prepared as organic fibers, and MFC (manufactured by Daicel Miraize Co., Ltd., product name "Cerish KY100G") was prepared as fine fibers. These were dissociated and dispersed in water in the blending ratio shown in Table 1, and then a wet strength agent (manufactured by Arakawa Chemical Industries, Ltd., product name "Arafix (registered trademark) AF255") and a flocculant were added to obtain a slurry with a concentration of 0.5%.

[0079] Next, a square hand-made papermaking machine (160 mmφ) was used as a laboratory papermaking machine to obtain a wet sheet, which was then dried at 140°C using a Yankee dryer to obtain the antibacterial and antiviral paper of Example 1.

[0080] Examples 2 to 4 The antibacterial and antiviral papers of Examples 2 to 4 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the blending ratio of each component was changed to the values ​​shown in Table 1.

[0081] Comparative Example 1 A suspension was prepared by suspending La2Mo2O9 and Ce5(MoO4)8 in water at a ratio of 1% by mass. The mass ratio of La2Mo2O9 to Ce5(MoO4)8 was 1:1. Commercially available filter paper (manufactured by ADVANTEC, 5C type) was cut into a size of 20 mm x 20 mm, and the filter paper was immersed in the suspension for 50 minutes while irradiated with 38 kHz ultrasound for 10 minutes. The filter paper was then removed from the suspension, drained, and dried overnight at a temperature of 60°C. In this way, paper of Comparative Example 1 was obtained. The particle ratio contained in the obtained paper was 14.8% by mass.

[0082] Comparative Example 2 Paper of Comparative Example 2 was obtained in the same manner as Comparative Example 1, except that the proportions of La2Mo2O9 and Ce5(MoO4)8 contained in the suspension were changed to 10 mass%. The proportion of particles contained in the obtained paper was 35.4 mass%.

[0083] Comparative Example 3 In Comparative Example 3, only filter paper was prepared.

[0084] 〔evaluation〕 (Thickness) The thickness of the antibacterial and antiviral paper etc. of Example 1 was measured using a micrometer.

[0085] (Antibacterial performance evaluation) The antibacterial and antiviral paper of Example 1 was subjected to an antibacterial performance evaluation test in accordance with JIS L 1902:2015 using the method described below. Specifically, grape vitriol was used as the test bacteria, and the antibacterial activity value R after 24 hours was determined. The antibacterial activity value R was calculated using the following formula (1). R=(logC t -logC0)-(logT t -logT0)=FG (1)

[0086] In the above (1), F(=logC t -logC0) represents the growth value of the standard fabric, and G(=logT t -logT0) represents the growth value of the antibacterial and antiviral paper. t is the common logarithm of the number of viable bacteria on the target fabric after 24 hours of incubation, logC0 is the common logarithm of the number of viable bacteria on the target fabric immediately after inoculation, and logT t is the common logarithm of the number of viable bacteria on the antibacterial / antiviral paper after 24 hours of incubation, and logT0 is the common logarithm of the number of viable bacteria on the antibacterial / antiviral paper immediately after inoculation. However, when logC0 > logT0, the antibacterial activity value was calculated by replacing logT0 with logC0. The results are shown in Table 1.

[0087] The antibacterial activity values ​​of the antibacterial and antiviral papers of Examples 3 and 4 and the filter paper of Comparative Example 3 were also determined in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0088] (SEM image) The antibacterial and antiviral papers of Examples 1 and 2 were photographed using a scanning electron microscope (SEM) at an accelerating voltage of 5 kV and magnifications of 100x, 1000x, and 3000x. The results are shown in Figures 1 and 2.

[0089] Furthermore, the paper of Comparative Example 2 was photographed using an SEM under conditions of an acceleration voltage of 5 kV and magnifications of 100x, 1000x, and 10000x. The results are shown in FIG.

[0090] (Dropout test) The antibacterial and antiviral paper (20 mm x 20 mm) from Example 1 was immersed in 100 mL of pure water, and in that state, it was irradiated with 38 kHz ultrasound for 3 minutes using an ultrasonic cleaner. The antibacterial and antiviral paper was then lightly washed in pure water and dried. The ceramic particle residual rate (%) was then calculated based on the following formula (2):

[0091] Ceramic particle residual rate (%) = (mass of paper before test - mass of paper after test) / (mass of paper before test) × 100 (2)

[0092] The antibacterial and antiviral papers of Examples 2 to 4 and the papers of Comparative Examples 1 and 2 were also subjected to a dropout test to determine the ceramic particle residual rate (%) in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0093] [Table 1]

[0094] [Table 2]

[0095] As shown in Table 1, the antibacterial and antiviral paper of Example 1 had an antibacterial activity value of 4.8, confirming its excellent antibacterial properties. In addition, the particle residual rate (%) after the shedding test was 88.0%.

[0096] Figure 1 shows SEM images of the antibacterial and antiviral paper of Example 1. Figure 1(A) is an SEM image of Example 1 at 100x magnification, Figure 1(B) is an SEM image of Example 1 at 1000x magnification, and Figure 1(C) is an SEM image of Example 1 at 3000x magnification. As shown in Figure 1, it was confirmed that the ceramic particles La2Mo2O9 and Ce5(MoO4)8 were primarily held by the fine fibers that make up the antibacterial and antiviral paper. As shown in Figure 1(C), the ceramic particles were held in a manner that they were embraced by the fine fibers.

[0097] As shown in Table 1, the antibacterial and antiviral paper of Example 2 had a particle retention rate (%) of 97.7% after the shedding test. Example 2 contained more ceramic particles than Example 1, and thus had antibacterial properties equivalent to or greater than those of Example 1. Figure 2 shows SEM images of the antibacterial and antiviral paper of Example 2. Figure 2(A) is an SEM image of Example 2 at 100x magnification, Figure 2(B) is an SEM image of Example 2 at 1000x magnification, and Figure 2(C) is an SEM image of Example 2 at 3000x magnification. As shown in Figure 2, it was confirmed that the ceramic particles La2Mo2O9 and Ce5(MoO4)8 were primarily held by the fine fibers that make up the antibacterial and antiviral paper. As shown in Figure 2(C), the ceramic particles were held in a manner that they were embraced by the fine fibers.

[0098] As shown in Table 1, the antibacterial and antiviral paper of Example 3 had an antibacterial activity value of 3.1, confirming its excellent antibacterial properties. In addition, the particle residual rate (%) after the shedding test was 93.8%.

[0099] As shown in Table 1, the antibacterial and antiviral paper of Example 4 had an antibacterial activity value of 5.8, confirming its excellent antibacterial properties. In addition, the particle residual rate (%) after the shedding test was 84.7%.

[0100] The particle remaining rate (%) after the peeling test for the paper of Comparative Example 1 was 67.0%, as shown in Table 2. In Comparative Example 1, although the ceramic particles were attached to the surface of the fibers that make up the paper, the ceramic particles were easily peeled off from the fibers that make up the paper after the peeling test.

[0101] Figure 3 shows SEM images of the paper of Comparative Example 2. Figure 3(A) is an SEM image of Comparative Example 2 at 100x magnification, Figure 3(B) is an SEM image of Comparative Example 2 at 1000x magnification, and Figure 3(C) is an SEM image of Comparative Example 2 at 3000x magnification. As shown in Table 2, the particle residual rate (%) of the paper of Comparative Example 2 after the drop test was 48.6%. As shown in Figure 3, in Comparative Example 2, although ceramic particles adhered to the surface of the fibers that make up the paper, the ceramic particles easily peeled off from the fibers that make up the paper after the peel test.

[0102] Comparative Example 3 was the case where only filter paper was used, and as shown in Table 2, the antibacterial activity value was less than 1.

Claims

1. An antibacterial and antiviral paper comprising antibacterial and antiviral ceramic particles mainly composed of a La-Mo based composite oxide and / or a Ce-Mo based composite oxide, and organic fibers, the average fiber diameter of the organic fibers is larger than the average particle diameter of the ceramic particles, The fiber diameter of the fine fibers is smaller than the average particle diameter, The antibacterial and antiviral paper has the fine fibers that hold the ceramic particles.

2. The antibacterial and antiviral paper according to claim 1 , wherein the organic fibers are not fibrillar fibers.

3. 3. The antibacterial and antiviral paper according to claim 1, wherein the fine fibers are fibrillated fibers.

4. 3. The antibacterial and antiviral paper according to claim 1, wherein the average fiber diameter of the organic fibers is 2 μm or more and 100 μm or less.

5. 3. The antibacterial and antiviral paper according to claim 1, wherein the fiber diameter of the fine fibers is 0.05 μm or more and 20 μm or less.

6. Basis weight: 30 g / m ２ More than 200g / m ２ The antibacterial and antiviral paper according to claim 1 or 2, wherein:

7. 3. The antibacterial and antiviral paper according to claim 1, wherein the content of the ceramic particles is 5% by mass or more and 80% by mass or less.

8. The La-Mo based composite oxide is ２ Mo ２ O ９ and the Ce—Mo-based composite oxide is Ce ５ (MoO ４ ) ８ 3. The antibacterial and antiviral paper according to claim 1 or 2, wherein

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