Particles and methods for manufacturing the particles

Abstract

The present invention provides particles that do not discolor when used in coatings, possess sufficient hardness (pencil hardness) and strength (scratch resistance), high dispersibility, and high antibacterial and antiviral properties, as well as a method for producing the same. [Solution] These particles are silica-alumina particles containing silver ions. In the absorption spectrum of an aqueous dispersion of these particles with a solid content of 1.5% by mass, measured by ultraviolet-visible spectroscopy, the ratio of the area of ​​the peak with a peak top at a wavelength of 200-240 nm to the area of ​​the peak with a peak top at a wavelength of 200-700 nm is 75% or more, and the average particle diameter (R1) measured by dynamic light scattering is 10-100 nm. These particles have sufficient hardness and strength even in the acidic pH range, high dispersibility, and at least one of high antibacterial and antiviral properties.

Description

[Technical Field]

[0001] This invention relates to particles supported with silver ions, and also to a method for producing said particles. [Background technology]

[0002] Conventionally, anti-reflective coatings have been applied to the surfaces of substrates such as sheets and lenses made of glass, plastic, etc., to prevent reflection. However, components that require transparency and anti-reflective properties include, for example, display devices with touch panels such as smartphones, ATMs, and ticket vending machines. These surfaces are contaminated with bacteria such as E. coli and Staphylococcus aureus, as well as various viruses, and from a hygienic standpoint, antibacterial and antiviral properties are required.

[0003] Regarding the imparting of antibacterial and antiviral properties to coatings, it has been conventionally known to coat the surface of the coating with antibacterial or antiviral agents. For example, with organic antibacterial or antiviral agents, the coating itself is relatively easy, but there is a risk that the coating may be damaged by the solvent, and there are problems with the durability of the antibacterial performance in terms of adhesion to the coating and scratch resistance. On the other hand, with inorganic antibacterial or antiviral agents, durability of antibacterial and antiviral performance can be expected if they are present in the coating, but it is necessary to manufacture a separate coating containing them. For example, if the anti-reflective layer and the antibacterial or antiviral layer are manufactured separately, there is a risk that the effect of the layers that are not on the outermost surface will be insufficient, and that productivity will decrease and production costs will increase. In contrast, if low refractive index components, antibacterial and antiviral components are incorporated into a single coating, there is a risk that the anti-reflective performance, antibacterial performance, and antiviral performance will be insufficient, or that the transparency and strength of the coating will be insufficient.

[0004] Known antimicrobial agents include powders such as silica gel, composite oxides, and titanium dioxide, or antimicrobial compositions in which silver, zinc, copper, or other antimicrobial materials are supported on colloidal particles. Specifically, known examples include antimicrobial compositions in which silver ions and zinc ions are exchanged on zeolite particles (e.g., Patent Document 1), antimicrobial zinc oxide-based powders (e.g., Patent Document 2), antimicrobial titanium dioxide powders containing potassium and phosphorus (e.g., Patent Document 3), titanium dioxide particles containing iron(III) compounds (e.g., Patent Document 4), and composite oxide particles of silica-alumina on which silver, etc., are supported (e.g., Patent Document 5). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2008-001557 [Patent Document 2] International Publication No. 2013 / 073555 [Patent Document 3] Japanese Patent Publication No. 2021-031450 [Patent Document 4] Japanese Patent Publication No. 2007-090336 [Patent Document 5] Japanese Patent Application Publication No. 7-033616 [Overview of the project] [Problems that the invention aims to solve]

[0006] In a coated substrate containing particles having antibacterial properties, if the particle size is about micrometers, a large amount of the particles must be incorporated to obtain the desired antibacterial properties, and there is a risk that the dispersion stability of the coating solution containing the particles will decrease. In addition, the hardness, strength, transparency, and glossiness of the coated substrate may be impaired (for example, Patent Documents 1 to 3). On the other hand, particles having a size smaller than the micrometer order, such as in the nanometer order, for example, of the particles having antibacterial properties have higher dispersibility and a larger number per unit amount, so that sufficient antibacterial properties can be easily exhibited even with a small amount of the particles incorporated in the coated substrate. However, if the site where the antibacterial property is expressed is an oxidative decomposition reaction, there is a risk that the dispersion medium, the substrate, etc. will also decompose (for example, Patent Document 4). Further, if Ag, which is a metal element exhibiting antibacterial properties, is mixed in the particles as Ag2O, there is a risk that Ag2O will react with other compositions to exhibit coloring, or that the particles will aggregate during solvent dispersion because they are non-uniform (for example, Patent Document 5). Furthermore, if particles with low stability are mixed, there are problems such as low concentration stability of the dispersion liquid and inability to make it highly concentrated, an increase in the amount of the dispersion medium brought into the coating solution, a decrease in productivity in the production of the coated substrate using a low-concentration coating solution, and a decrease in the particle dispersibility in the film.

[0007] Therefore, particles that do not cause coloring when used in a film, have sufficient hardness (pencil hardness) and strength (scratch resistance), high dispersibility, and high antibacterial and antiviral properties are required.

Means for Solving the Problems

[0008] In order to solve such problems, the following particles have been found.

[0009] This particle is a particle containing silica alumina containing silver ions. In the absorption spectrum by ultraviolet-visible spectroscopy in an aqueous dispersion with a solid content concentration of 1.5% by mass of this particle, the ratio of the area of the peak having a peak top at a wavelength of 200 to 240 nm to the area of the peak having a peak top at a wavelength of 200 to 700 nm is 75% or more. Further, this particle has an average particle diameter (R1) of 10 to 100 nm by the dynamic light scattering method.

[0010] This particle has sufficient hardness, strength, and high dispersibility even in an acidic pH region, and has at least one of high antibacterial performance and antiviral performance. According to a coating liquid containing such particles, a film having suppressed coloring, sufficient hardness and strength, transparency, and having at least one of high antibacterial performance and antiviral performance can be obtained.

[0011] In order to obtain this particle, a production method including the following steps was found.

[0012] First, an acidic mixed solution containing a silicic acid solution obtained by ion-exchanging an aqueous sodium silicate solution, an acidic aluminum aqueous solution, and an organic acid is prepared (first step). The acidic mixed solution prepared in the first step is added to an alkaline mother solution containing seed particles to prepare particles containing silica alumina (second step). The total content of alkali metals and alkaline earth metals in the particles containing silica alumina prepared in the second step is made less than 0.50% by mass on an oxide basis (third step). An organic acid and a silver compound are added to the aqueous dispersion of the particles obtained in the third step to support silver ions on the particles (fourth step). <0​​​​​​​​​​[Modes for carrying out the invention]

[0015] The particles according to the present invention (hereinafter, these particles according to the present invention may be simply referred to as "particles") are particles containing silica alumina containing the element silver. In other words, they are particles in which the element silver is supported on silica alumina particles. In the absorption spectrum obtained by ultraviolet-visible spectroscopy (UV-Vis method) in an aqueous dispersion of these particles with a solid content of 1.5 mass%, the ratio of the area of ​​the peak with a peak top at a wavelength of 200 to 240 nm to the area of ​​the peak with a peak top at a wavelength of 200 to 700 nm is 75% or more. Furthermore, these particles have an average particle diameter (R1) of 10 to 100 nm as determined by dynamic light scattering.

[0016] The silver element supported on the particles has at least one of antibacterial and antiviral properties (hereinafter, this "at least one of antibacterial and antiviral properties" according to the present invention may simply be referred to as "antibacterial and antiviral properties"). A coated substrate using these particles exhibits antibacterial and antiviral properties.

[0017] In supported silver elements, the higher the proportion of silver ions, the more effectively discoloration due to tarnishing is suppressed compared to metallic silver.

[0018] Silica-alumina particles are used to support the silver element. Silica-alumina is porous and has a high specific surface area, allowing it to support a large amount of silver, especially silver ions.

[0019] Silica alumina is included as the main component in the particles. The silica alumina is not particularly limited as long as it satisfies the properties and performance of the particles of the present invention. Examples of its types include amorphous silica alumina, zeolite, activated clay, etc. Among these, amorphous silica alumina is preferred because it is porous, has a high specific surface area, and can produce a coating solution that can create a film with sufficient hardness, strength, and transparency.

[0020] Silver ions contained within particles exist either "isolated" or as "clusters." Here, the absorption spectrum of a 1.5% by mass aqueous dispersion of particles is observed at wavelengths of 200-700 nm using ultraviolet-visible spectroscopy. At this time, peaks with peak tops between 200 nm and 240 nm are classified as "isolated silver ion" peaks, peaks with peak tops between 240 nm and 350 nm are classified as "silver ion clusters (sometimes called "silver cluster ions")" peaks, and peaks with peak tops between 350 nm and 700 nm are classified as "metallic silver" peaks.

[0021] In this UV-Vis spectroscopy absorption spectrum, the ratio of the area of ​​peaks with peak tops at wavelengths of 200-240 nm to the area of ​​peaks with peak tops at wavelengths of 200-700 nm is 75% or more. In other words, when the ratio of peaks related to "lone silver ions" to the sum of peaks related to "silver ions and metallic silver" is within this range, discoloration due to tarnishing is suppressed compared to metallic silver.

[0022] Here, if the ratio of the area of ​​the peak with a peak top at a wavelength of 200 to 240 nm to the area of ​​the peak with a peak top at a wavelength of 200 to 700 nm is less than 75%, there is a risk that discoloration due to tarnishing will increase compared to metallic silver. The ratio of the area of ​​the peak with a peak top at a wavelength of 200 to 240 nm to the area of ​​the peak with a peak top at a wavelength of 200 to 700 nm is preferably 77% or more, more preferably 80% or more, even more preferably 83% or more, particularly preferably 85% or more, and most preferably 100%.

[0023] In an aqueous dispersion of the aforementioned particles with a solid content concentration of 1.5% by mass, the ratio of the area of ​​the peak with a peak top at wavelengths between 200 and 240 nm to the area of ​​the peak with a peak top at wavelengths between 240 nm and 350 nm, as observed by ultraviolet-visible spectroscopy, is preferably 3.0 or higher. In other words, this ratio is the ratio of the area of ​​the peak related to "lone silver ions" to the area of ​​the peak related to "silver cluster ions". When this ratio is within this range, UV oxidation becomes less likely, and discoloration due to discoloration is suppressed.

[0024] Here, if the ratio of the area of ​​the peak with a peak top at wavelengths between 200 and 240 nm to the area of ​​the peak with a peak top at wavelengths between 240 nm and 350 nm is less than 3.0, there is a risk that silver ions may be released from the particles. In addition, the particles may become more susceptible to UV oxidation, which may lead to discoloration. The ratio of the area of ​​the peak with a peak top at wavelengths between 200 and 240 nm to the area of ​​the peak with a peak top at wavelengths between 240 nm and 350 nm is more preferably 4.0 or higher, even more preferably 4.5 or higher, and particularly preferably 5.0 or higher.

[0025] The average particle size (R1) determined by dynamic light scattering of particles is 10 to 100 nm. When the average particle size is within this range, the particles can exist stably. Furthermore, they exhibit good dispersibility in coating solutions and films, resulting in films with high transparency, hardness, and strength.

[0026] In this case, particles with an average particle diameter of less than 10 nm have low stability and small volume, resulting in a small amount of antibacterial and antiviral metal elements being supported. Conversely, if the particle diameter exceeds 100 nm, the dispersibility in the coating solution is low, which may prevent the desired antibacterial and antiviral performance from being obtained. In addition, light scattering is likely to occur, which may prevent the acquisition of a transparent coating. The average particle diameter is preferably 20 to 90 nm, more preferably 30 to 70 nm.

[0027] Examples of metal elements possessing antibacterial and antiviral properties include elements selected from silver, copper, zinc, lead, tin, and bismuth. These metal elements may exist individually or in combination within the particles. Among these, preferred metal elements are silver, copper, and zinc, more preferably silver and zinc, and particularly preferred silver. These metal elements are preferably in the form of ions or complexes, more preferably ions. This form allows for effective expression of antibacterial and antiviral properties.

[0028] Of these metallic elements, it is preferable that the silver element be present in the particles at a concentration of 1.0 to 3.0% by mass, based on Ag (silver). A silver content within this range ensures sufficient antibacterial and antiviral performance.

[0029] If the silver content is less than 1.0% by mass, sufficient antibacterial and antiviral performance may not be obtained. Conversely, if it exceeds 3.0% by mass, the antibacterial and antiviral performance will not improve significantly, and in some cases, the silver-containing component may become unstable, making it prone to release from particles or discoloration. The silver content is more preferably 1.2 to 3.0% by mass, and even more preferably 1.5 to 2.5% by mass.

[0030] When the total silica and alumina content of the silica-alumina contained in the particles is taken as 100 parts by mass, the silica content is preferably 92 to 99 parts by mass as SiO2. When the silica content is within this range, the aqueous dispersion of the particles has a high surface charge and high particle dispersibility, even in acidic regions.

[0031] Here, if the silica content is less than 92 parts by mass, the number of Si-O-Si bonds decreases, and the particle strength weakens. For example, this may prevent the particle shape from being maintained at the pH of the aqueous dispersion of particles as described above. Conversely, if it exceeds 99 parts by mass, there may not be enough acid sites on the particle surface, resulting in insufficient space for silver ions to be supported. The silica content is more preferably 94 to 98 parts by mass, and even more preferably 95 to 97 parts by mass.

[0032] When the total silica and alumina content of silica-alumina is 100 parts by mass, the alumina content is preferably 1 to 8 parts by mass as Al2O3. When the alumina content is within this range, the aqueous dispersion of particles exhibits high dispersibility, even in acidic regions such as pH 2. Furthermore, it can support a sufficient amount of silver ions to exhibit antibacterial and antiviral properties.

[0033] Here, if the alumina content is less than 1 part by mass, the acid sites on the particle surface will decrease, and there may be insufficient space for silver ions to be supported. Conversely, if it exceeds 7 parts by mass, the absolute value of the zeta potential of the aqueous dispersion of particles will be small at pH 2. Therefore, there is a risk of particle aggregation in the acidic region. The alumina content is more preferably 2 to 6 parts by mass, and even more preferably 3 to 5 parts by mass.

[0034] The molar ratio of silica-alumina (SiO2 / Al2O3) is preferably between 20 and 170. When the molar ratio (SiO2 / Al2O3) is within this range, the aqueous dispersion of particles (e.g., solid content concentration of 5% by mass) has a high surface charge and high particle dispersibility, even in acidic regions such as pH 2. Furthermore, it can support a sufficient amount of silver ions to exhibit antibacterial and antiviral properties, while maintaining sufficient particle strength.

[0035] Here, if the molar ratio of silica-alumina (SiO2 / Al2O3) is less than 20, the number of Si-O-Si bonds decreases, and the particle strength weakens. As a result, the particles in the dispersion may not be able to maintain their shape at pH 5 or below. Conversely, if it exceeds 170, the amount of silver ions supported may become insufficient. The molar ratio (SiO2 / Al2O3) is more preferably 30 to 100, and even more preferably 30 to 60.

[0036] Preferably, the ratio (R1 / R2) of the average particle diameter (R1) measured by dynamic light scattering to the average particle diameter (R2) obtained by converting the specific surface area to an equivalent sphere using the Sears method is 1.4 to 10. When the ratio (R1 / R2) is within this range, there is a sufficient surface area on the particles for supporting silver ions to exhibit antibacterial and antiviral properties. More specifically, because the particles are porous and have a high specific surface area, they can support a large amount of silver ions.

[0037] Here, if the ratio of average particle diameters (R1 / R2) is less than 1.4, the specific surface area of ​​the particles may be low, potentially resulting in insufficient silver ion loading. Conversely, if it exceeds 10, the particles may aggregate, potentially preventing the antibacterial and antiviral effects of high dispersibility as nano-sized particles from being achieved. This ratio (R1 / R2) is more preferably 1.4 to 8, and even more preferably 2 to 5.

[0038] The specific surface area of ​​the particles, calculated using the Sears method, is 250-350 m². 2 A specific surface area of ​​ / g is preferable. This is because a specific surface area within this range results in a highly porous structure with a large surface area, allowing it to support a large amount of silver ions, which have antibacterial and antiviral properties.

[0039] Here, the specific surface area of ​​the particle is 250 m². 2 If the amount is less than / g, the surface area may be insufficient, and the amount of silver ions that can be supported may be insufficient. Conversely, 350m 2 If the specific surface area exceeds 1 / g, the particles may become too small, reducing stability and making them prone to aggregation. More preferably, the specific surface area is 280-350 m². 2 / g, more preferably 300-350m 2 It is / g.

[0040] Particle 29 In Si-NMR analysis, it is preferable that the ratio ((Q3+Q4) / ΣQ) × 100) of the area of ​​the peak representing the Q3 structure (appearing at a chemical shift of -82.0 to -100.0 ppm) and the area of ​​the peak representing the Q4 structure (appearing at a chemical shift of -100.0 to -120.0 ppm) to the sum of the areas of the peaks representing the Q0 to Q4 structures (appearing at a chemical shift of -73.0 to -120.0 ppm) is 90 to 97%. Here, ΣQ = Q0 + Q1 + Q2 + Q3 + Q4. A higher proportion of structures above Q3 results in a stronger Si-O framework in the particles, leading to high acid and organic solvent resistance, and achieving sufficient hardness and strength in the particles.

[0041] If this ratio is less than 90%, the acid resistance will be low, and the particle shape may not be maintained in an acidic atmosphere. Conversely, if it exceeds 97%, the amount of aluminum constituting the particles will be small, which may result in an insufficient content of silver element, which has antibacterial and antiviral properties. This ratio is more preferably 93-97%, and even more preferably 96-97%.

[0042] Particle 27 In Al-NMR analysis, it is preferable that the ratio (I4 / I6) of the area of ​​the peak representing the 4-coordinate structure appearing at a chemical shift of 80.0 to 30.0 ppm (I4) to the area of ​​the peak representing the 6-coordinate structure appearing at a chemical shift of 30.0 to -30.0 ppm (I6) is substantially 100 / 0. "Substantially 100 / 0" means that the peak representing the 6-coordinate structure is observed at a level equivalent to noise during measurement, for example, when the area (I6) is less than 1%.

[0043] Here, if silicon has a Si-O skeleton with a Q3 structure or higher, and aluminum (Al) has a 4-coordinate structure, it can take on a three-dimensional structure as a carrier particle. As a result, even under acidic conditions, the particles do not disintegrate due to the elution of Al, nor do they cause contamination by the eluted substances. Furthermore, the permanent charge due to Al substitution is maintained, allowing the particle to support silver ions that have antibacterial and antiviral properties.

[0044] The alumina content of the particles is preferably 2 to 7.8% by mass as Al2O3. This alumina content ensures sufficient acid sites for supporting silver ions, which have antibacterial and antiviral properties. More preferably, the alumina content is 2 to 5% by mass, and even more preferably 3 to 4% by mass.

[0045] In an aqueous dispersion of particles with a solid content concentration adjusted to 0.5% by mass, it is preferable that the absolute value of the zeta potential at pH 2 is 10 mV or higher. When the zeta potential is within this range, the particles exhibit high dispersibility. Furthermore, the supported silver ions are also highly dispersed.

[0046] Here, if the zeta potential is less than 10 mV, the particle dispersibility is low and there is a risk of aggregation. Also, the supported silver ions may not be highly dispersed and may aggregate. There is no particular upper limit set for the zeta potential, but for example it is 40 mV. The zeta potential is more preferably 15 to 40 mV, and even more preferably 20 to 40 mV.

[0047] There are no particular restrictions on the shape of the particles. Examples include spherical, ellipsoidal (rugby ball) shape, cocoon shape, konpeito shape, chain shape, and cube shape. Among these, spherical particles are preferred because they have high dispersibility and can be uniformly dispersed in the coating. Furthermore, in order to support a larger amount of silver ions with antibacterial and antiviral properties and to improve the scratch resistance of the coating, it is preferable for the surface of the particles to have some irregularities rather than being smooth. Having irregularities on the particle surface allows for a higher surface area compared to particles with the same particle size but a smooth surface, making it possible to support a larger amount of silver ions with antibacterial and antiviral properties.

[0048] The alkali metal content of the particles is preferably less than 0.50% by mass in total, based on oxides.

[0049] Here, if the alkali metal content is 0.50% by mass or more, the particles may aggregate, which may reduce the dispersibility of the particles in the coating solution or film, result in insufficient film hardness, or result in insufficient transparency. The alkali metal content is more preferably less than 0.30% by mass, even more preferably less than 0.10% by mass, and most preferably no alkali metals are present. Incidentally, if the particles contain alkaline earth metals, the above-mentioned "alkali metal content" should be read as "total content of alkali metals and alkaline earth metals." Alkali metals refer to Li, Na, K, Rb, Cs, and Fr, and alkaline earth metals refer to Be, Mg, Ca, Sr, Ba, and Ra.

[0050] The anion content in the dispersion is preferably less than 200 ppm. Here, anions include, for example, sulfate ions, nitrate ions, chloride ions, etc. When the anion content is within this range, the silver ions supported on the particles can exist in a stable state without bonding with other ions.

[0051] Here, if the content of these anions is 200 ppm or more, the supported silver ions may dissolve into the dispersion and become free silver ions. The content of the anions is more preferably less than 100 ppm, and even more preferably less than 50 ppm.

[0052] In an aqueous dispersion of particles with a solid content of 1.5% by mass, the light transmittance is preferably 80.0% or higher.

[0053] If the light transmittance is less than 80.0%, the transmittance of the resulting coating may be insufficient. More preferably, the light transmittance is 90.0% or higher.

[0054] The particles may be surface-treated with known organosilicon compounds such as silane coupling agents. Surface-treated particles exhibit high dispersibility in the particle dispersion medium, the coating solution for film formation, or the matrix of the coating. A coated substrate using these particles exhibits suppressed particle aggregation and possesses sufficient hardness and strength.

[0055] [Coating liquid for film formation] The particles of the present invention can be applied to coating solutions for film formation. This coating solution contains particles and matrix-forming components. In addition, it may contain additives such as organic dispersion media, polymerization initiators, leveling agents, and surfactants. Furthermore, known antibacterial and antiviral agents (components) other than those of the present invention may be used in combination with this coating solution. These antibacterial and antiviral agents may be "inorganic" or "organic." Examples of "inorganic" agents include silver, copper, silver oxide, copper oxide, silver zeolite, copper zeolite, and silver-copper zeolite. Examples of "organic" agents include silver complexes, benzalkolium chloride, benzatonium chloride, parahydroxybenzoic acid esters, lysine, polylysine, alkyl(diaminoethyl)glycine hydrochloride, and quaternary ammonium salts. Examples of these quaternary ammonium salts include monoalkylammonium salts, dialkylammonium salts, tetraalkylammonium adipate, metosulfate-type cationic ammonium salts, and ethylene oxide (EO)-added ammonium salts.

[0056] [Coated base material] The particles of the present invention can be used in materials requiring antibacterial and antiviral properties. These particles not only possess high antibacterial and antiviral properties, but also suppress discoloration of compositions and have sufficient hardness and strength. Therefore, they can be used, for example, in coating solutions capable of forming a film. Furthermore, this coating solution can be used to produce coated substrates requiring antibacterial and antiviral properties.

[0057] The coated substrate according to the present invention is a coated substrate on which a coating containing the above-mentioned particles and a matrix is ​​formed. The matrix consists of solid components other than particles, and includes resins derived from the coating solution and additives such as polymerization initiators and leveling agents. Specifically, the coating solution is applied to the substrate by a known method, and then dried and irradiated with ultraviolet light to form a coating on the substrate. In the coating, the ratio of particles to solid components of the matrix forming components in the coating solution is directly equal to the ratio of particle components to matrix in the coating.

[0058] Between this coating and the substrate, conventionally known hard coat layers, anti-glare layers, high refractive index layers, conductive layers, etc., may be arranged depending on the application. Multiple layers can also be combined. For example, when further reducing reflectivity in a transparent coated substrate for display applications, a combination of a hard coat layer and a high refractive index layer, or a combination of a hard coat layer and an anti-glare layer, are examples of such combinations.

[0059] The film thickness can be appropriately selected depending on the application. For example, for anti-reflective coatings, 80 to 350 nm is preferred.

[0060] If the film thickness is less than 80 nm, the film's strength and scratch resistance may be insufficient. Also, if the film is too thin, sufficient anti-reflective performance may not be obtained. Conversely, if it is thicker than 350 nm, the anti-reflective performance may decrease. Furthermore, if the shrinkage is very large, cracks may occur. This film thickness is more preferably 85 to 220 nm, and even more preferably 90 to 110 nm.

[0061] The reflectance of the substrate with a transparent coating having anti-reflective properties is preferably 2.0% or less, and more preferably 1.5% or less.

[0062] Furthermore, the haze of the transparent coated substrate is preferably 3.0% or less, and more preferably 0.3% or less.

[0063] The total light transmittance of the transparent coated substrate is preferably 85.0% or higher.

[0064] If the total light transmittance is less than 85.0%, the image clarity in the display device or other device using the resulting coating may be insufficient. More preferably, the total light transmittance is 90.0% or higher.

[0065] The strength (scratch resistance) of the coating was tested using #0000 steel wool under a load of 1000 g / cm². 2 The material is evaluated by sliding it. Preferably, no streaky scratches are observed on the film surface after at least 100 sliding cycles. More preferably, no scratches are observed after 500 cycles, and even more preferably, no scratches are observed after 1000 cycles.

[0066] The pencil hardness of the coating is preferably H or higher. Below H, the hardness is insufficient for an anti-reflective coating. This pencil hardness is more preferably 2H or higher, and even more preferably 3H or higher.

[0067] The antibacterial properties of the coating shall be tested in accordance with JIS Z 2801. A value of 2.0 or higher is preferable. A value of 2.0 or higher indicates antibacterial properties. A value of 4.0 or higher is more preferable.

[0068] The antiviral activity test of the coating shall be conducted in accordance with ISO 21702. A value of 2.0 or higher is preferable. A value of 2.0 or higher indicates that the coating possesses antiviral properties. A value of 3.0 or higher is more preferable for antibacterial activity.

[0069] Any known substrate can be used. For example, transparent resin substrates such as glass, polycarbonate, acrylic resin, polyethylene terephthalate (PET), triacetylcellulose (TAC), polyimide, polymethyl methacrylate (PMMA), and cycloolefin polymer (COP) are preferred. These substrates exhibit excellent adhesion to the transparent film formed by the above-mentioned coating solution, and a coated substrate with excellent hardness, strength, etc., can be obtained. For this reason, they are suitably used for thin substrates. There are no particular restrictions on the thickness of the substrate, but 10 to 100 μm is preferred, and more preferably 20 to 80 μm.

[0070] [Method for manufacturing particles] The present invention provides a method for producing particles, comprising: a first step of preparing an acidic mixture containing a silicic acid solution obtained by ion exchange of an aqueous sodium silicate solution, an acidic aqueous aluminum solution, and an organic acid; a second step of adding the acidic mixture prepared in the first step to an alkaline mother liquor containing seed particles to produce particles containing silica alumina; a third step of reducing the total content of alkali metals and alkaline earth metals in the silica alumina particles produced in the second step to less than 1.0% by mass; and a fourth step of adding an organic acid and an aqueous dispersion to an aqueous dispersion of particles obtained in the third step to support silver ions on the particles.

[0071] The "silicate solution obtained by ion-exchanging an aqueous sodium silicate solution" and the "acidic aluminum aqueous solution" used in the first step are acidic aqueous solutions. In the "acidic mixed solution" obtained by mixing these with an organic acid, precipitation of composite oxide particles such as silica-alumina particles does not occur, and it can be added as a homogeneous solution. The "silicate solution" used here has its sodium content reduced in advance by ion-exchange. Therefore, the load of washing for reducing the contents of alkali metals and alkaline earth metals in the particles can be reduced. Further, examples of the "acidic aluminum aqueous solution" used include aqueous solutions of aluminum sulfate, aluminum nitrate, aluminum chloride, etc. Among these, an aqueous solution of aluminum sulfate is preferably used because of its low corrosivity and reduced load of wastewater treatment. For the added "acidic mixed solution", it is preferable to use one from which sulfate ions (SO4 2- ) etc. have been removed for stable particle growth.

[0072] Further, examples of the "organic acid" used include tartaric acid, citric acid, malic acid, glycolic acid, lactic acid, gluconic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, formic acid, acetic acid, salicylic acid, coumaric acid, etc. Among these, tartaric acid, citric acid, and malic acid are preferably used because of their high chelating action.

[0073] The amount of the organic acid used is preferably 0.03 to 0.2 times the molar amount in terms of oxide (Al2O3) of the aluminum aqueous solution used. When the amount of the organic acid is within this range, the chelating action of the organic acid works effectively.

[0074] Here, if the amount of the organic acid is less than 0.03 times the molar amount, the chelating action of the organic acid may be insufficient. Conversely, if it is more than 0.2 times the molar amount, the organic acid becomes excessive and the particles may become unstable. The amount of this organic acid is more preferably 0.05 to 0.15 times the molar amount, and even more preferably 0.05 to 0.1 times the molar amount.

[0075] In the second step, when producing the "silica-alumina particles," the acidic mixture prepared in the first step is added to the alkaline mother liquor containing the seed particles. At this time, it is preferable to maintain the pH of the reaction solution alkaline from the start to the end of the addition. For this reason, when adding the acidic mixture prepared in the first step, it is preferable to either adjust the pH of the mother liquor to a high level beforehand, or to simultaneously add an alkaline solution such as an aqueous sodium hydroxide solution or aqueous ammonia solution.

[0076] In the third step, the total amount of alkali metals and alkaline earth metals contained in the silica-alumina particles produced in the second step is reduced to less than 0.50% by mass on an oxide basis. When the total content of alkali metals and alkaline earth metals is within this range, silver ions can be highly dispersed and supported on the particles. To reduce the content of alkali metals and alkaline earth metals in the particles, it is preferable to wash them using a cation exchange resin or an ultrafiltration membrane.

[0077] Here, if the alkali metal content is 0.50% by mass or more, there is a risk that ion exchange from protons to silver may be inhibited when the silver compound is added to the particles in the fourth step described later, or that the pH of the aqueous dispersion may become basic, causing the silver to become unstable. The alkali metal content is preferably less than 0.30% by mass, more preferably less than 0.10% by mass, even more preferably less than 500 ppm, and most preferably no alkali metals are present.

[0078] In the third step, it is preferable to keep the anion content in the silica-alumina particles produced in the second step below 200 ppm. These anions are preferably washed away using an anion exchange resin or an ultrafiltration membrane. Here, anions include, for example, sulfate ions, nitrate ions, chloride ions, etc. When the anion content is within this range, the silver ions supported on the particles in the fourth step, described later, can exist in a stable state without binding with other ions.

[0079] Here, if the content of these anions is 200 ppm or more, the supported silver ions may dissolve into the dispersion and become free silver ions. The content of the anions is more preferably less than 100 ppm, and even more preferably less than 50 ppm.

[0080] Incidentally, the particles produced in this third step become the carrier particles used to support silver ions in the fourth step. As mentioned above, these carrier particles have a silicon backbone with a Q3 structure or higher and Al has a 4-coordinate structure, so the particles can have a three-dimensional bonding state, appropriate acid sites, and surface irregularities. For this reason, the particles have high acid resistance and a large specific surface area. Such particles can be used in the fourth step to stably support silver ions by adding a silver compound. Therefore, discoloration of the composition can be suppressed.

[0081] Examples of silver compounds used in the fourth step include solutions of metal salts such as hydrochloride, nitrate, sulfate, and acetate, as well as metal complex ions and solutions of metal alkoxides. Among these, silver nitrate is more preferred.

[0082] Examples of organic acids used in the fourth step include those used in the first step. These may be the same type as those used in the first step, or they may be different. Multiple organic acids may also be used. Among these, citric acid, tartaric acid, and malic acid are preferred due to their high chelating properties with metals.

[0083] The organic acid used here is preferably in an amount of 0.03 to 0.2 molars relative to the molar amount of the silver compound oxide (Ag2O) used. When the amount of organic acid is within this range, the chelating effect of the organic acid works effectively.

[0084] Here, if the amount of organic acid is less than 0.03 molars, the chelating effect of the organic acid may be insufficient. Conversely, if it is more than 0.2 molars, the organic acid will be in excess, and the particles may become unstable. The amount of organic acid is more preferably 0.05 to 0.15 molars, and even more preferably 0.05 to 0.1 molars.

[0085] The order in which the silver compound and organic acid are added to the aqueous dispersion of particles obtained in the third step is not particularly limited. For example, methods include adding the organic acid after the silver compound, adding the silver compound after the organic acid, adding the silver compound and organic acid simultaneously, and mixing the silver compound and organic acid beforehand before adding them. In particular, it is preferable to mix the silver compound and organic acid beforehand to form a silver complex, as this allows for stable and highly dispersed support of silver ions.

[0086] When adding the organic acid and silver compound to the aqueous dispersion of particles obtained in the third step, it is preferable to maintain the reaction site temperature below 30°C. A temperature below 30°C suppresses the aggregation of the silver component, making it easier for the silver ions to be supported on the particles.

[0087] Here, if the temperature is 30°C or higher, the silver component may aggregate and form silver cluster ions or metallic silver. There is no specific lower limit for the temperature, but considering that the dispersion medium is water, it can be set at a temperature at which water does not freeze, for example, 1°C. The temperature at which the silver compound is added is more preferably less than 25°C, even more preferably less than 10°C, and particularly preferably less than 5°C.

[0088] After adding the silver compound, stirring and stagnation are preferable to promote the support of silver ions. The temperature during this process is preferably maintained below 30°C, similar to the temperature at which the silver compound was added. Within this temperature range, aggregation of the silver component is suppressed, and the silver ions are supported on the particles.

[0089] Here, if the temperature during stirring and retention is 30°C or higher, the silver component may become silver cluster ions or metallic silver, similar to when adding the silver compound. There is no specific lower limit for the temperature, but considering that the dispersion medium is water, it can be set at a temperature at which water does not freeze, for example, 1°C. The temperature when adding the silver compound is preferably less than 25°C, more preferably less than 10°C, and even more preferably less than 5°C.

[0090] The stirring and retention time after adding the silver compound is preferably 40 minutes or more. There is no particular upper limit set for this time, but considering production efficiency, for example, it would be 120 minutes. More preferably, the stirring and retention time after adding the silver compound is 60 minutes or more, and even more preferably 90 minutes or more.

[0091] The amount of silver compound to be added is preferably such that the final amount of silver element supported in the particles is 1.0 to 3.0% by mass as Ag. When adding the silver compound, it may be added in multiple stages to ensure more precise support of the silver ions or to increase the silver ion content. The amount of silver compound added is more preferably 1.2 to 3.0% by mass, and even more preferably 1.5 to 2.5% by mass, as the final amount of Ag supported in the particles.

[0092] When adding the silver compound in the fourth step, there are no particular restrictions other than those mentioned above, as long as the desired particle properties are ultimately satisfied. However, the concentration of the aqueous dispersion of particles at this time is preferably 1 to 2% by mass as solid content. Furthermore, the pH when adding the silver compound is preferably 2 to 5.

[0093] Here, if the solid content concentration of the dispersion is less than 1% by mass, the production efficiency will be poor, and conversely, if it is greater than 2% by mass, the silver component may not be uniformly supported. This solid content concentration is more preferably 1.0 to 1.5% by mass, and even more preferably 1.0 to 1.2% by mass.

[0094] Furthermore, if the pH is less than 2, the Al in the particles may dissolve, making the particles unstable and potentially causing aggregation. Conversely, if the pH exceeds 5, the silver element may form an oxide, causing discoloration. The pH when adding the silver compound is more preferably 3 to 4.

[0095] For the reasons mentioned above, it is preferable that the silica-alumina particles containing silver ions obtained by the manufacturing method described above have an anion content of less than 200 ppm. These anions are preferably washed away using an anion exchange resin or an ultrafiltration membrane. When the anion content is within this range, the silver ions supported on the particles can exist in a stable state without binding with other ions.

[0096] Here, if the content of these anions is 200 ppm or more, the supported silver ions may dissolve into the dispersion and become free silver ions. The content of the anions is more preferably less than 100 ppm, and even more preferably less than 50 ppm.

[0097] The resulting particles may be used as an aqueous dispersion, or after being replaced with an organic dispersion medium, or they may be dried and used as a powder.

[0098] Furthermore, the physical properties and preferred ranges of the particles ultimately obtained by this manufacturing method are the same as those described above.

[0099] The following describes embodiments of the present invention.

[0100] [Example 1] <Preparation of acidic mixture (first step)> Sodium silicate No. 3 (manufactured by AGC SI-TEC Co., Ltd., SiO2 equivalent concentration 24% by mass) was diluted to 5% by mass with deionized water and cooled to 10°C. This was passed through a column packed with 1700 ml of strongly acidic cation exchange resin (Mitsubishi Chemical SK 1B) to obtain 9500 g of silica solution with an SiO2 equivalent concentration of 4.5% by mass. To 1489 g of this silica solution, an aqueous solution prepared by mixing 860.7 g of deionized water and 26.3 g of aluminum sulfate 14-18 water was added and mixed.

[0101] Next, 70 g of anion exchange resin (SA 10A, manufactured by Mitsubishi Chemical Corporation) was added to this mixture to remove SO4, and then the ion exchange resin was separated to obtain the mixture. Furthermore, 0.63 g of tartaric acid was added to this mixture.

[0102] <Preparation of silica-alumina particles (second step)> In a 5L stainless steel separable flask set on a mantle heater, 1002.3g of deionized water and 12.5g of sodium silicate (No. 3) were added and stirred. 51.9g of silicic acid solution (SiO2 equivalent concentration 4.5% by mass) was then added, and the temperature was raised to 79°C. This temperature was maintained for 30 minutes to prepare an alkaline mother liquor containing silica seed particles.

[0103] Next, while maintaining the mother liquor temperature at 79°C, 2376 g of the acidic mixture prepared in the first step and 1358 g of a 1.0% by mass sodium hydroxide aqueous solution were continuously added to the mother liquor over 20 hours. The pH of the reaction solution was maintained alkaline from the start to the end of the addition. After the addition was completed, the mixture was kept at 79°C for 30 minutes and then cooled to obtain 4800 g of a dispersion of silica-alumina particles. This dispersion was then concentrated to 766 g using an ultrafiltration membrane (SIP-1013, manufactured by Asahi Kasei Corporation), and while maintaining the liquid level at this time, 4600 g of deionized water was continuously added for washing. The solid content concentration of this washed product was 10% by mass.

[0104] <Adjustment of alkali metal content in silica-alumina particles (third step)> In a separable flask, 108.8 g of the washed dispersion of silica-alumina particles prepared in the second step and 531 g of deionized water were placed, and the mixture was heated to 60°C while stirring. Next, 50 g of strongly acidic cation exchange resin (SK 1B, manufactured by Mitsubishi Chemical Corporation) was added over 10 minutes, stirred for 20 minutes, and then cooled to 35°C. After that, the resin was separated along with 267 g of deionized water used for washing to obtain 878 g of an aqueous dispersion of silica-alumina particles with adjusted alkali metal content. The pH at this time was 3.0 and the temperature was 22°C. The solid content concentration was 1.2% by mass, the alkali metal content of the particles was 0.26% by mass on an oxide basis, and the anion content was 0 ppm.

[0105] <Supporting silver ions onto silica-alumina particles (fourth step)> 878 g of the aqueous dispersion of particles obtained in the third step was placed in a separable flask and adjusted to 10°C. Next, 90.5 g of an aqueous silver nitrate solution, adjusted to 0.47% by mass (in terms of Ag) using deionized water, and 0.083 g of citric acid monohydrate were mixed and adjusted to 10°C. This mixture was added to the aforementioned aqueous dispersion of particles over 40 minutes while stirring. The mixture was then maintained at this temperature for 4 hours. Subsequently, the mixture was washed using an ultrafiltration membrane (SIP-1013, manufactured by Asahi Kasei Corporation) while supplying deionized water until the electrical conductivity was 100 μs / cm or less. The resulting dispersion of silver-supported particles had a solid content of 1.5% by mass, a pH of 3.6, and a nitrate ion content of 3 ppm.

[0106] The particles and their dispersions were measured using the following method.

[0107] Tables 1 and 2 show the characteristics of each manufacturing process for the particles and the properties of the particles and their dispersions (the same applies to the following examples and comparative examples).

[0108] (1) Measurement of silver ions The state of silver in the dispersion was measured using ultraviolet-visible light. Specifically, a self-recording spectrophotometer (Shimadzu Corporation UV-3100) with an integrating sphere attachment (Shimadzu Corporation ISR-3100) mounted in the sample chamber was used, with a scan speed of 200 nm / min and a measurement wavelength range of 200 to 700 nm.

[0109] Next, the total absorbance at wavelengths of 200-700 nm was calculated, i.e., the area of ​​the peak with its peak top at wavelengths of 200-700 nm. The absorbance in each wavelength region was then calculated as a percentage (area ratio) using this peak area as a baseline of 100. Specifically, the area ratio for absorbance between 200 nm and 240 nm, and the area ratio for absorbance between 240 nm and 350 nm were calculated. Here, the peak with its peak top between 200 nm and 240 nm was identified as the "isolated silver ion" peak, the peak with its peak top between 240 nm and 350 nm as the "silver cluster ion" peak, and the peak with its peak top between 350 nm and 700 nm as the "metallic silver" peak. The proportion of silver ions and silver cluster ions was then determined from the peak areas of each obtained peak.

[0110] (2) Average particle diameter (R1) The average particle size (R1) of the particle dispersion was measured using a particle size analyzer (ELSZ-2000, manufactured by Otsuka Electronics Co., Ltd.) by dynamic light scattering (cumulant method).

[0111] (3) Specific surface area and average particle diameter (R2) by Sears method A sample (a dispersion of particles) equivalent to 1.5 g of SiO2 was placed in a beaker and transferred to a constant-temperature reaction vessel maintained at 25°C. Pure water was added to bring the volume to 90 ml. Next, 0.1 mol / L hydrochloric acid aqueous solution was added to bring the pH to 3.6, then 30 g of sodium chloride was added, the mixture was diluted to 150 ml with pure water, and stirred for 10 minutes. Next, a pH electrode was set up, and 0.1 mol / L sodium hydroxide solution was added dropwise while stirring to adjust the pH to 4.0. This dispersion adjusted to pH 4.0 was titrated with 0.1 mol / L sodium hydroxide solution, and the titration volume and pH value were recorded at four or more points in the pH range of 8.7 to 9.3. A calibration curve was created by plotting the titration volume of 0.1 mol / L sodium hydroxide solution on the X axis and the corresponding pH value on the Y axis. Furthermore, the amount of 0.1 mol / L sodium hydroxide solution consumed per 1.5 g of SiO2, V (ml), is calculated from equation (1) to change the pH from 4.0 to 9.0. The specific surface area SA (m²) is then calculated from equation (2). 2 The amount per g was calculated. The average particle size R2 (nm) was calculated using equation (3).

[0112] V=(A×f×100×1.5) / (W×C) ···(1) (Here, A represents the titration volume (ml) of 0.1 mol / L sodium hydroxide solution required to change the pH from 4.0 to 9.0 per 1.5 g of SiO2, f represents the titer of the 0.1 mol / L sodium hydroxide solution, C represents the SiO2 equivalent concentration (mass%) of the sample (particle dispersion), and W represents the sample volume (equivalent to 1.5 g of SiO2).) SA=29.0V-28 ···(2) R² = 6000 / (ρ × SA) ... (3) (Here, ρ is the density of the particles (g / cm³) 3 This represents ( ). For silica, substitute 2.2. )

[0113] (4) Observation of particle surface shape Using a field emission scanning electron microscope (Hitachi High-Technologies Corporation, S-5500), the shape of the particle surface was observed at a magnification of 300,000 times.

[0114] (5) 29 Si-NMR analysis Approximately 100 mg of the dried particles were densely packed into a 5 mm diameter zirconia rotor and tested on a 14.1T NMR spectrometer (Agilent VNMRS-600). 1 Using the H resonance frequency of 600 MHz, 29 Measurements were performed on the Si nucleus (119.2 MHz). A single-pulse non-decoupling method was used for NMR measurement, with 128 integration cycles and a waiting time of 400 seconds. Polydimethylsiloxane (-34.44 ppm) was used as the reference material. Waveform analysis was performed on the obtained spectra to determine the chemical shifts and integral values ​​of each signal. From these chemical shifts, the components Q0, Q1, Q2, Q3, and Q4 were assigned, and the area percentage was calculated from the integral values ​​of each component.

[0115] (6) 27 Al-NMR analysis Approximately 20 mg of the dried particles were densely packed into a 3.2 mm diameter zirconia rotor, and NMR was performed using a 14.1 T NMR spectrometer (Agilent VNMRS-600, 1H resonance frequency 600 MHz). 27 Al nuclei (156.3 MHz) were measured. A single-pulse method was used for the NMR measurement, with a pulse flip angle of 10°, 256 integrations, and a waiting time of 0.1 seconds. A 1 mol / L Al(NO3)3 aqueous solution was used as the reference material.

[0116] (7) Zeta potential First, pure water was added to adjust the solid content concentration of the aqueous dispersion of particles to 0.5% by mass. This was then adjusted to pH levels of 11, 10, 9, 8, 7, 6, 5, 4, 3, and 2. For the acidic pH, a 0.25-0.5% by mass hydrochloric acid aqueous solution was used, and for the alkaline pH, a 0.25-0.5% by mass sodium hydroxide aqueous solution was used. The zeta potential at each adjusted pH was measured using a Malvern Zetasizer nanoZS.

[0117] (8) Particle shape and surface irregularities Using a field emission scanning electron microscope (Hitachi High-Technologies Corporation, S-5500), the shape of the particle surface was observed at a magnification of 300,000 times.

[0118] (9) Dispersion solid content concentration The particle dispersion was subjected to loss of volume at 1000°C and weighed to determine the result.

[0119] (10) Metal element concentration The content of each element was measured by the following method. First, a sample equivalent to approximately 0.2 g of solid content was placed in a platinum dish. To this, 3 ml of phosphoric acid, 5 ml of nitric acid, and 10 ml of hydrofluoric acid were added and heated on a sand bath. After drying, a small amount of water and 50 ml of nitric acid were added to dissolve it, and the solution was transferred to a 100 ml volumetric flask, where water was added to make a total volume of 100 ml. Alkali metals such as Na and alkaline earth metals were measured using an atomic absorption spectrometer (Hitachi, Ltd. Z-2310). For Ag and Al, the solution was taken from the 100 ml solution prepared above and measured using an ICP plasma emission spectrometer (SII Corporation SPS5520).

[0120] (11) Anion concentration The content of each anion was measured by ion chromatography. Specifically, 1-2 g of sample was taken and diluted with 200 ml of water to prepare the sample solution. Next, the area of ​​nitrate, chloride, and sulfate ions was measured using standard data to create a calibration curve. Then, the area of ​​the sample solution was measured to determine the concentrations of nitrate, chloride, and sulfate ions.

[0121] (12) Concentration of SiO2 10 g of particle dispersion was mixed with 2 ml of a 50% by mass sulfuric acid aqueous solution and evaporated to dryness on a platinum dish. The resulting solid was calcined at 1000°C for 1 hour, then cooled and weighed. Next, the weighed solid was dissolved in a small amount of a 50% by mass sulfuric acid aqueous solution. Furthermore, 20 ml of hydrofluoric acid was added, and the mixture was evaporated to dryness on a platinum dish, calcined at 1000°C for 15 minutes, cooled and weighed. The silica content was determined from the difference in mass.

[0122] (13) Light transmittance of particle dispersion The solid content concentration of the dispersion was adjusted to 1.5% by mass using distilled water. The light transmittance at a wavelength of 500 nm was measured using a 10 mm glass cell with distilled water as the target solution, using a spectrophotometer (Shimadzu Corporation UV-1800).

[0123] <Manufacturing of MIBK dispersion> A dispersion of particles equivalent to 8 g of solids was concentrated to 267 g using an ultramechanism (Sartorius Vivaflow Mw10000). Next, 1600 g of methanol was continuously added while draining the filtrate to replace the solvent with methanol. The solid content of this methanol dispersion of particles was 3.7% by mass, and the water content was 0.3% by mass. 90 g of this methanol dispersion was transferred to a plastic container, and 21 g of methanol was added to adjust the solid content to 3% by mass. Next, while stirring, 0.33 g of a silane coupling agent (KBM503, Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was stirred for a further 30 minutes. Then, the container was sealed and stirred in a constant temperature bath maintained at 50°C for 15 hours to produce particles surface-treated with the silane coupling agent. 80 g of this methanol dispersion of surface-treated particles was transferred to a round-bottom flask, and 150 g of methyl isobutyl ketone (MIBK) was added. This was attached to a rotary evaporator, and under reduced pressure, the solvent was replaced with MIBK in a water bath maintained at 80°C to prepare a granular MIBK dispersion. The solid content of this MIBK dispersion was 2.0% by mass, and the water content was 0.2% by mass.

[0124] <Manufacturing of coating solution for forming a protective layer> A coating solution for film formation was prepared by adding the aforementioned MIBK dispersion of particles (solid content concentration 2.0% by mass) to an anti-reflective coating (also called anti-reflection coating or AR coating) (ELCOM-P-5062, manufactured by JGC Catalysts & Chemicals Co., Ltd., solid content concentration 3.0% by mass) so that the particle ratio in terms of solid content was 5% by mass.

[0125] <Manufacturing of coated substrates> A hard coat coating (ELCOM HP-1004, manufactured by JGC Catalysts & Chemicals Co., Ltd.) was applied to a TAC film (FT-PB80UL-M, manufactured by Panac Co., Ltd., 80 μm thick, refractive index 1.51) using the bar coater method (#18), and dried at 80°C for 120 seconds. Afterward, a pressure of 300 mJ / cm² was applied. 2 A hard coat film was fabricated by irradiating and curing it with ultraviolet light. The thickness of this hard coat film was 8 μm.

[0126] Next, a coating solution for film formation using the particles of the present invention was applied by bar coating (#4) and dried at 80°C for 120 seconds. After that, 400 mJ / cm² was applied under an N2 atmosphere. 2 A coated substrate was manufactured by irradiating and curing it with ultraviolet light.

[0127] The coated substrate was measured for the following items. The results are shown in Table 3 (the same applies to the following examples and comparative examples).

[0128] (14) Film thickness, reflectance An ellipsometer (EMS-1, manufactured by ULVAC, Inc.) was used to measure the film thickness and reflectance at a wavelength of 550 nm of the coated substrate.

[0129] (15) Haze, total light transmittance A haze meter (manufactured by Suga Test Instruments Co., Ltd.) was used to measure the haze and total light transmittance of the coated substrate.

[0130] (16) Strength (scratch resistance) Using #0000 steel wool, with a load of 1000g / cm² 2 The substrate was slid 100 times. The surface of the coated substrate was visually inspected after sliding and evaluated according to the following criteria. Evaluation criteria; No linear scars were observed: ◎ Slight, linear scarring is observed: ○ Numerous linear scars are observed: △ The entire surface is worn down: ×

[0131] (17) Hardness (pencil hardness) The hardness was measured using a pencil hardness tester in accordance with JIS-K-5400.

[0132] (18) Antimicrobial test The antibacterial activity test was conducted in accordance with JIS Z 2801, and the antibacterial activity value was determined using the following formula (4).

[0133] Q B =U Bt -A Bt ...(4) (However, Q B This is the antibacterial activity value, U Bt This is the 1cm measurement of an unprocessed test specimen after 24 hours. 2 The average of the logarithmic values ​​of the number of viable bacteria per unit, A Bt This is the 1cm measurement of the antibacterial treated test piece after 24 hours. 2 (This shows the average of the logarithmic values ​​of the number of viable bacteria per unit.)

[0134] We determined that an antibacterial effect was present if the antibacterial activity value was 2.0 or higher.

[0135] The test organisms used were Staphylococcus aureus (NBRC 12732) and Escherichia coli (NBRC 3972), and 1 / 500 standard bouillon medium (3g meat extract + 10g peptone, 5.0g sodium chloride per 1000ml of medium) was used as nutrients.

[0136] For the measurement, 0.4 ml of bacterial solution was dropped onto a 5 cm square coated substrate and an untreated film, and then covered with a 4 cm square PE film. The test pieces were incubated at 35°C ± 1°C and a relative humidity of 90% or higher for 24 hours. The test bacteria on the test pieces were washed off with 10 ml of SCDLP medium and collected, and the number of viable bacteria in the wash solution was measured using the plate pour culture method in a 1 cm square. 2 The number of viable bacteria per serving was measured.

[0137] (19) Antiviral test Antiviral testing was conducted in accordance with ISO 21702, and the antiviral activity value was determined using the following formula (5).

[0138] QV =U Vt -A Vt ...(5) (However, Q V This is the antiviral activity value, U Vt This is the 1cm measurement of an unprocessed test specimen after 24 hours. 2 The average of the logarithmic values ​​of the viral infectivity titer per unit, A Vt This is the 1 cm measurement of the antiviral treated test piece after 24 hours. 2 (This shows the average of the logarithmic values ​​of the viral infectivity titer per unit.)

[0139] We determined that the drug had an antiviral effect if its antiviral activity value was 2.0 or higher.

[0140] The measurements were taken on a coated substrate cut into 5cm squares and an unprocessed film, measuring 1 to 5 x 10 cm each. 7 0.4 ml of a virus suspension (influenza A virus (H3N2) ATCC VR-1679) prepared at pfu / ml was dropped onto the specimen and covered with a 4 cm square PE film. The specimen was incubated at 25°C ± 1°C and relative humidity of 90% or higher for 24 hours. The test bacteria on the specimen were washed off with 10 ml of SCDLP medium and collected. A 10-fold dilution series of the wash solution was then prepared, and plaque analysis was performed on a 1 cm² sample. 2 The viral infectivity titer per sample was measured.

[0141] (20) UV resistance test of the coating A coating solution for UV resistance testing was prepared by adding the aforementioned MIBK dispersion of particles to a hard coat paint (ELCOM HP-1004, manufactured by JGC Catalysts & Chemicals Co., Ltd.) so that the particle ratio in terms of solid content was 20% by mass.

[0142] Next, the solution was applied to a 10cm x 10cm FL glass substrate (FL3, manufactured by Hamashin Glass Co., Ltd., 3mm thick) using the bar coater method (#18) and dried at 80°C for 120 minutes. After that, a 300mJ / cm² test was performed. 2 A hard coat film was fabricated by irradiating and curing it with ultraviolet light. The thickness of this hard coat film was 3 μm.

[0143] This hard coat film was measured at 60W / m using a xenon weather meter (NX75, manufactured by Suga Test Co., Ltd.). 2 The samples were irradiated for 500 hours, and the degree of yellowing (ΔYI value) before and after irradiation was measured using a color computer (COH-400 model, manufactured by Nippon Denshoku Industries Co., Ltd.) to determine the degree of yellowing (ΔYI value).

[0144] [Example 2] A particle dispersion was prepared in the same manner as in Example 1, except that in the first step, 1560 g of silicic acid solution, 809 g of deionized water, 6.6 g of aluminum sulfate-14-18 water, and 0.16 g of tartaric acid were used, and in the second step, the concentration of the aqueous sodium hydroxide solution added was set to 0.26% by mass. This dispersion was then used to produce a coating solution and a coated substrate.

[0145] [Example 3] In the first step, 1505 g of silicic acid solution, 870 g of deionized water, and 26.6 g of aluminum sulfate 14-18 water were mixed, and after treating this mixture with an anionic resin, 0.64 g of tartaric acid was added to prepare the mixture in the same manner as in Example 1.

[0146] In the second step, an alkaline mother liquor containing silica seed particles was prepared in the same manner as in Example 1, except that 885.47 g of deionized water, 17.48 g of sodium silicate No. 3, and 8.0 g of silicic acid solution were used, and the temperature was set to 61°C.

[0147] Next, the mother liquor was kept at 61°C, and a washed product was obtained in the same manner as in Example 1, except that 2401 g of the mixture prepared in the first step and 1488 g of a sodium hydroxide aqueous solution with a concentration of 0.92% by mass were used. The solid content of this washed product was 10% by mass, and the alkali metal content was 0.3% by mass. The subsequent steps were the same as in Example 1 to produce a particle dispersion, which was then used to produce a coating solution and a coated substrate.

[0148] [Example 4] In the first step, a particle dispersion was prepared in the same manner as in Example 1, except that 0.31 g of tartaric acid was used. This dispersion was then used to produce a coating solution and a coated substrate.

[0149] [Example 5] In the first step, a particle dispersion was prepared in the same manner as in Example 1, except that 1473 g of silicic acid solution, 872 g of deionized water, 30.7 g of aluminum sulfate 14-18 water, and 0.73 g of tartaric acid were used. This dispersion was then used to produce a coating solution and a coated substrate.

[0150] [Example 6] In the fourth step, a particle dispersion was prepared in the same manner as in Example 1, except that the washing was completed when the electrical conductivity reached 300 μs / cm. This dispersion was then used to produce a coating solution and a coated substrate.

[0151] [Example 7] In the first step, a particle dispersion was prepared in the same manner as in Example 1, except that 0.19 g of tartaric acid was added. This dispersion was then used to produce a coating solution and a coated substrate.

[0152] [Example 8] In the first step, a particle dispersion was prepared in the same manner as in Example 1, except that 1.26 g of tartaric acid was added. This dispersion was then used to produce a coating solution and a coated substrate.

[0153] [Example 9] In the first step, a particle dispersion was prepared in the same manner as in Example 1, except that malic acid was used as the organic acid to be added. This dispersion was then used to produce a coating solution and a coated substrate.

[0154] [Example 10] In the third step, 5 g of strongly acidic cation exchange resin was added over 1 minute, and a particle dispersion was prepared in the same manner as in Example 1, except that stirring was not performed. This dispersion was then used to produce a coating solution and a coated substrate.

[0155] [Example 11] In the third step, a particle dispersion was prepared in the same manner as in Example 1, except that 100 g of a strongly acidic cation exchange resin was added over 20 minutes and stirred for 20 minutes. This dispersion was then used to produce a coating solution and a coated substrate.

[0156] [Example 12] In the second step, a particle dispersion was prepared in the same manner as in Example 1, except that 1600 g of ion-exchanged water was used for washing with an ultrafiltration membrane. This dispersion was then used to produce a coating solution and a coated substrate.

[0157] [Example 13] In the fourth step, a particle dispersion was prepared in the same manner as in Example 1, except that 0.03 g of citric acid monohydrate was added. This dispersion was then used to produce a coating solution and a coated substrate.

[0158] [Example 14] In the fourth step, a particle dispersion was prepared in the same manner as in Example 1, except that 0.17 g of citric acid monohydrate was added. This dispersion was then used to produce a coating solution and a coated substrate.

[0159] [Example 15] In the fourth step, a particle dispersion was prepared in the same manner as in Example 1, except that tartaric acid was used as the organic acid and 0.06 g of it was added. This dispersion was then used to produce a coating solution and a coated substrate.

[0160] [Example 16] In the fourth step, a particle dispersion was prepared in the same manner as in Example 1, except that the reaction temperature was set to 30°C. This dispersion was then used to produce a coating solution and a coated substrate.

[0161] [Comparative Example 1] In the fourth step, the temperature of the aqueous dispersion of particles obtained in the third step and the aqueous silver nitrate solution (without any organic acid) were both adjusted to 95°C. The aqueous silver nitrate solution was added to the aforementioned aqueous dispersion of particles over 40 minutes while stirring, and the mixture was held at this temperature for 4 hours. The particle dispersion was then produced in the same manner as in Example 1, and this was used to produce the coating solution and the coated substrate.

[0162] [Comparative Example 2] In the first step, 1505 g of silicic acid solution, 870 g of deionized water, and 26.6 g of aluminum sulfate 14-18 water were mixed. After treating this mixture with an anionic resin, 1.28 g of tartaric acid was added to prepare the mixture in the same manner as in Example 1.

[0163] In the second step, an alkaline mother liquor containing silica seed particles was prepared in the same manner as in Example 1, except that 885.47 g of deionized water, 17.48 g of sodium silicate No. 3, and 8.0 g of silicic acid solution were used, and the temperature was set to 61°C.

[0164] Next, the mother liquor was kept at 61°C, and a washed product was obtained in the same manner as in Example 1, except that 2401 g of the mixture prepared in the first step and 1488 g of a sodium hydroxide aqueous solution with a concentration of 0.92% by mass were used. The solid content of this washed product was 10% by mass, and the alkali metal content was 0.3% by mass. The subsequent steps were the same as in Example 1 to produce a particle dispersion, which was then used to produce a coating solution and a coated substrate.

[0165] [Comparative Example 3] In the first step, a particle dispersion was prepared in the same manner as in Example 1, except that the amount of tartaric acid added was 0 g. This dispersion was then used to produce a coating solution and a coated substrate.

[0166] [Comparative Example 4] In the second step, 1600 g of ion-exchanged water was used for washing with an ultrafiltration membrane, and in the third step, 5 g of strongly acidic cation exchange resin was added over 1 minute. The particle dispersion was prepared in the same manner as in Example 1, except that no stirring was performed. This dispersion was then used to produce a coating solution and a coated substrate.

[0167] [Table 1]

[0168] Table 2

[0169] Table 3

Claims

1. Particles containing silica alumina containing the element silver, In the absorption spectrum obtained by ultraviolet-visible spectroscopy of an aqueous dispersion of the aforementioned particles with a solid content concentration of 1.5% by mass, the ratio of the area of ​​the peak with a peak top at a wavelength of 200 to 240 nm to the area of ​​the peak with a peak top at a wavelength of 200 to 700 nm is 75% or more. The average particle diameter (R) of the aforementioned particles as determined by dynamic light scattering. １ Particles with a diameter of 10 to 100 nm.

2. The particle according to claim 1, wherein in the absorption spectrum, the ratio of the area of ​​the peak having a peak top at a wavelength of 200 to 240 nm to the area of ​​the peak having a peak top at a wavelength of more than 240 nm and less than or equal to 350 nm is 3.0 or more.

3. The particles according to claim 1, wherein the content of the silver element is 1.0 to 3.0% by mass as Ag.

4. When the total of the silica content and alumina content of the silica-alumina is 100 parts by mass, the silica content is SiO ２ The alumina content is 93 to 99 parts by mass. ２ O ３ The amount is 1 to 7 parts by mass, and the molar ratio is (SiO ２ / Al ２ O ３ The particle according to claim 1, wherein the value of the particle is 20 to 170.

5. The average particle diameter (R １ ), and the average particle diameter (R ２ ) obtained by equivalent sphere conversion from the specific surface area by the shear method, and the ratio (R １ / R ２ ) is 1.4 to 10. The particle according to claim 1.

6. ２９ Q is a chemical shift that appears in the range of -73.0 to -120.0 ppm as determined by Si-NMR analysis. ０ ~Q ４ Q is the chemical shift that appears between -82.0 and -100.0 ppm relative to the sum of the areas of each peak representing the structure. ３ The area of ​​the peak representing the structure, and the Q value where the chemical shift appears between -100.0 and -120.0 ppm. ４ The particle according to claim 1, wherein the sum of the areas of the peaks representing the structure is 90 to 97%.

7. The particle according to claim 1, wherein the absolute value of the zeta potential at pH 2 of an aqueous dispersion of the particle having a solid content concentration of 0.5% by mass is 10 mV or more.

8. The particles according to claim 1, wherein the alkali metal content is less than 0.50% by mass on an oxide basis.

9. The particles according to claim 1, wherein the light transmittance in an aqueous dispersion with a solid content concentration of 1.5% by mass is 80.0% or more.

10. The first step involves preparing an acidic mixture containing a silicic acid solution obtained by ion exchange of an aqueous sodium silicate solution, an acidic aqueous aluminum solution, and an organic acid. A second step involves adding the aforementioned mixture to an alkaline mother liquor containing seed particles to produce particles containing silica alumina, A third step is to make the total oxide-based content of alkali metals and alkaline earth metals in the silica-alumina-containing particles less than 0.50% by mass, A fourth step involves adding an organic acid and a silver compound to the aqueous dispersion of particles obtained in the third step to support silver ions on the particles. A method for producing particles having the following characteristics.

11. The method for producing particles according to claim 10, wherein in the fourth step, the organic acid and the silver compound are added while maintaining the temperature of the aqueous dispersion below 30°C.

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