Titania-coated silver and titania-coated silver-containing compositions

Abstract

The present invention aims to provide new titania-coated silver and titania-coated silver-containing compositions. [Solution] The present invention provides titania-coated silver in which Ti particles are coated on the surface of Ag particles. The present invention also provides a titania-coated silver-containing composition containing the titania-coated silver, a Si compound which is a hydrolysis product of alkoxysilane, and a solvent. The titania-coated silver-containing composition of the present invention combines transparency, adhesion to a substrate, durability, antibacterial and antiviral properties, and long-term stability.

Description

Technical Field

[0001] The present invention relates to titania-coated silver and a composition containing titania-coated silver.

Background Art

[0002] Patent Document 1 discloses an antibacterial liquid containing antibacterial agent fine particles, a binder, and a solvent, wherein the antibacterial agent fine particles include silver-supported inorganic oxides, the binder includes a compound having at least one siloxane bond, the solvent includes alcohol and water, the solid content concentration with respect to the total mass of the antibacterial liquid is less than 5% by mass, and the content of the compound having a siloxane bond with respect to the total solid content of the antibacterial liquid is 60% by mass or more.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to newly provide titania-coated silver and a composition containing titania-coated silver.

Means for Solving the Problems

[0005] The present invention includes the following titania-coated silver and a composition containing titania-coated silver.

[0006] Item 1. Titania-coated silver in which the surface of Ag particles is coated with Ti particles.

[0007] Item 2. The titania-coated silver according to claim 1, wherein the titania-coated silver contains 4 or more Ti particles per one Ag particle.

[0008] Section 3. The titania-coated silver according to claim 1, wherein the titania-coated silver has a coating rate of 5% to 95%.

[0009] Section 4. The titania-coated silver according to claim 1, wherein when the Ti particles are heated to 600°C using a thermogravimetric simultaneous thermometer, the mass loss at temperatures above 200°C is 1% by mass or more.

[0010] Section 5. The titania-coated silver according to claim 1, wherein the Ti particles have an average primary particle diameter of 1 nm to 20 nm.

[0011] Section 6. The titania-coated silver according to claim 1, wherein the Ag particles have an average primary particle diameter of 1 nm to 2,000 nm.

[0012] Section 7. The ratio of the average primary particle diameter of the Ag particles to the average primary particle diameter of the Ti particles contained in the titania-coated silver is: (Average primary particle diameter of Ag particles / Average primary particle diameter of Ti particles) The titania-coated silver according to claim 1, wherein the coefficient is 2 to 100.

[0013] Section 8. (A) Titania-coated silver as described in any of claims 1 to 7, (B) Si compounds, and (C) Contains a solvent, The (B)Si compound is a titania-coated silver-containing composition which is a hydrolysis product of an alkoxysilane.

[0014] Section 9. The titania-coated silver-containing composition according to item 8, wherein the content of the Ti particles contained in the titania-coated silver (A) is 0.01% by mass to 5% by mass.

[0015] Section 10. In the titania-coated silver-containing composition, the content of the (B) Si compound is 0.01% by mass to 20% by mass. The titania-coated silver-containing composition according to claim 8.

[0016] Item 11. The (C) solvent includes water and alcohol. The titania-coated silver-containing composition according to claim 8.

[0017] Item 12. The (B) Si compound is a hydrolysis product of tetraethyl orthosilicate (TEOS). The titania-coated silver-containing composition according to claim 8.

[0018] Item 13. An antibacterial and antiviral coating liquid containing the titania-coated silver-containing composition according to claim 8.

[0019] The titania-coated silver of the present invention is such that a part of the surface of the Ag (silver) particles is coated with titania.

[0020] The titania-coated silver-containing composition of the present invention can improve the adhesion to the substrate by mixing the titania-coated silver with a binder. The titania-coated silver-containing composition is a material that has transparency, adhesion to the substrate, durability, antibacterial and antiviral properties (antibacterial agent), long-term stability, etc. by performing hydrolysis of alkoxysilane in coexistence with the titania-coated silver.

Effects of the Invention

[0021] The present invention can newly provide titania-coated silver.

[0022] The composition containing the titania-coated silver of the present invention has transparency, adhesion to the substrate, durability, antibacterial and antiviral properties, and long-term stability.

Modes for Carrying Out the Invention

[0023] The present invention will be described in detail below.

[0024] The embodiments illustrating the present invention are intended to provide a better understanding of the invention's intent and, unless otherwise specified, do not limit the scope of the invention.

[0025] In this specification, "contains" and "include" are concepts that encompass all of "comprise," "consist essentially of," and "consist of."

[0026] In this specification, when a numerical range is indicated as "A to B", it means "greater than or equal to A and less than or equal to B".

[0027] In this specification, the notations "parts," "%," etc., are generally used.

[0028] In this specification, unless otherwise specified, parts by mass or mass % (wt%) are used.

[0029] [1](A) Titania-coated silver Traditionally, organic antibacterial agents have been known for their rapid action but short-lived effectiveness, while inorganic antibacterial agents have long-lasting effects but are colored, have low transparency, and are of poor performance. Further research is needed to address these issues.

[0030] Conventionally, while silver nanoparticles possess high antibacterial and antiviral properties, they have low stability and are prone to aggregation and caking, requiring further investigation.

[0031] The prior art (Patent Document 1) discloses a technique for preventing caking of antibacterial solutions by supporting silver on an inorganic oxide and further compounding it with a binder having siloxane bonds. The method of supporting silver on an inorganic oxide requires supporting the silver on a larger-sized support (inorganic oxide) compared to the silver itself, and stabilizing it. Conventionally, if the particle size of the support is large, the transparency of the antibacterial solution decreases. Thus, there is a trade-off between stably supporting silver on a support in the antibacterial solution and the transparency of the antibacterial solution, and a material that can achieve both is needed.

[0032] The inventors have shifted their approach from conventional methods of supporting silver on a support and succeeded in minimizing silver aggregation in a composition (such as an antibacterial solution) by using Ti particles (titania particles) that are significantly smaller than Ag particles to partially coat the silver.

[0033] The titania-coated silver of the present invention has Ti particles coated on the surface of Ag (silver) particles.

[0034] Titania-coated silver has a structure in which a portion of the surface of Ag particles is coated with Ti particles (titanium oxide, titania compounds, or titania nanoparticles). Titania-coated silver has a structure in which Ti particles are supported around Ag particles (carriers), or a structure in which Ti particles coat the Ag particles.

[0035] The present invention provides a structure in which Ti particles (titania particles) are supported around Ag particles, that is, a structure in which Ti particles coat the Ag particles. The titania-coated silver composition of the present invention contains a composite of fine titania-coated silver particles, is highly transparent, has low silver aggregation, is stable, and can exhibit antiviral properties.

[0036] Ti particles (titanium dioxide, titania compounds, titania nanoparticles) Water, inorganic acids, and liberated organic acids generally volatilize almost completely below 200°C. The Ti particles of titania-coated silver have acetyl groups (CH3-C(=O)-, Ac) and acetoxy groups (acetyloxy group, CH3-C(=O)-O-, AcO) bonded to at least some of the titanium atoms on their surface, and these gradually detach in the range of 200°C to 600°C. For example, in the case of acetoxy groups, detachment occurs gradually in the range of 200°C to 600°C, with a peak at approximately 260°C.

[0037] The dispersibility of Ti particles can be improved by applying organic matter to the fine titania surface.

[0038] Preferably, the Ti particles have organic chains such as acetyl groups and acetoxy groups bonded to at least some of the titanium atoms on their surface. This suppresses aggregation of Ti particles during drying or firing, making them less prone to cracking and peeling, and resulting in excellent coatability and transparency. Because the Ti particles can suppress cracking and peeling, and are more likely to firmly support metals, they also exhibit excellent visible photocatalytic activity.

[0039] Because the aggregation of Ti particles can be suppressed during drying or firing, they exhibit particularly excellent crack and peeling prevention effects.

[0040] When at least some of the titanium atoms on the surface of Ti particles have organic chains such as acetyl groups or acetoxy groups, these gradually detach in the range of 200°C to 600°C. Therefore, when the temperature is increased using a differential thermogravimetric analysis device (TG-DTA), the mass loss is significant above 200°C.

[0041] When Ti particles are heated to 600°C using a differential thermogravimetric analyzer (TG-DTA), the mass loss above 200°C indicates the number of organic chains, such as acetyl groups and acetoxy groups, that are bonded to the titanium atoms on the surface.

[0042] The Ti particles contained in the titania-coated silver preferably exhibit a mass loss of 1% by mass or more at temperatures above 200°C when the Ti particles are heated to 600°C using a differential thermogravimetric analyzer (TG-DTA). When the Ti particles are heated to 600°C using a differential thermogravimetric analyzer (TG-DTA), the mass loss at temperatures above 200°C is preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably 5% by mass or more. The upper limit of the mass loss of the Ti particles is preferably about 20% by mass.

[0043] The detailed conditions for the differential thermogravimetric simultaneous thermometry device (TG-DTA) are: atmosphere: air, heating rate: 3°C / min.

[0044] The organic chains (acetyl groups, acetoxy groups, etc.) present on the surface of Ti particles are preferably acetyl groups (CH3-C(=O)-), acetoxy groups (CH3-C(=O)-O-), etc., from the viewpoint of water solubility, odor, volatility, harmfulness, and decomposability.

[0045] The organic chain may have at least one organic chain selected from the group consisting of the aforementioned organic chains attached to it. These organic chains may be attached individually, or two or more organic chains may be attached depending on the purpose.

[0046] The Ti particles contained in the titania-coated silver preferably have an average primary particle diameter of 1 nm to 50 nm. The average primary particle diameter of the Ti particles is preferably 1 nm to 50 nm, more preferably 1 nm to 20 nm, and even more preferably 1 nm to 10 nm. By adjusting the average primary particle diameter of the Ti particles to this range, it becomes possible to partially coat the Ag particles with Ti. The Ti particles can form a film with higher visible photocatalytic activity and higher transparency. The Ti particles have excellent coatability.

[0047] The average primary particle size of Ti particles is measured by electron microscopy (TEM) observation.

[0048] The specific surface area of ​​the Ti particles is preferably 150 m². 2 / g~500m 2 It is / g, more preferably 200m 2 / g~400m 2 The specific surface area of ​​the Ti particles is adjusted to this range, allowing for a moderate amount of Ag particles to partially coat the Ti particles around the silver. The Ti particles exhibit high visible photocatalytic activity.

[0049] The specific surface area of ​​Ti particles is measured by the BET method.

[0050] The concentrations of N, Cl, and S in the Ti particles can be preferably 0 to 5,000 ppm, more preferably 0 to 1,000 ppm. By adjusting the concentrations of N, Cl, and S in the Ti particles to this range, corrosion of the substrate can be suppressed. The concentrations of N, Cl, and S in the Ti particles mean that impurities derived from acidic Ti particle precursors such as TiCl4 and TiOSO4 are absent or present in very small amounts.

[0051] The concentrations of N, Cl, and S elements in Ti particles are measured by WDX (X-ray fluorescence).

[0052] The crystalline form of the Ti particles is preferably anatase type, more preferably a crystalline form containing 90% or more anatase type, and even more preferably a crystalline form that contains no crystalline forms other than anatase type and is 100% anatase type. By using anatase type Ti particles, the visible photocatalytic activity is improved.

[0053] Ag (silver) particles The Ag particles contained in the titania-coated silver preferably have an average primary particle diameter of 1 nm to 2,000 nm.

[0054] Measurement method for titania-coated silver Titania-coated silver is imaged using a transmission electron microscope (TEM), and the locations of Ag and Ti particles are determined by electron energy loss spectroscopy (EELS). Subsequently, three arbitrary Ag particles are extracted and binarized using WinROOF image processing software (Mitani Corporation). At this time, the number of Ti atoms, coverage, and particle size (average primary particle size) of the titania-coated silver are the average values ​​of the three particles.

[0055] Method for measuring the number of Ti particles After binarization, a "circular separation" function is performed to separate the overlap between Ag particles and Ti particles. This separates the effect of the overlap between Ag and Ti particles, making it possible to measure the number of Ti particles per Ag particle.

[0056] Next, the number of Ti particles per Ag particle is measured using the "shape measurement" function. Preferably, the number of Ti particles per Ag particle is 4 or more, more preferably 15 or more, and even more preferably 60 or more. An increase in the number of Ti particles per Ag particle means that the surface of the Ag particle is coated with fine Ti particles. This increases the specific surface area of ​​the titania-coated silver, increases the contact area with bacteria and viruses, and improves antibacterial and antiviral activity.

[0057] Ratio of the average primary particle diameter of Ag particles to the average primary particle diameter of Ti particles (Average primary particle diameter of Ag particles / Average primary particle diameter of Ti particles (α(Ag) / β(Ti))) Let α (nm) be the average primary particle diameter of the Ag particles, and β (nm) be the average primary particle diameter of the Ti particles. From this, α / β is calculated. Preferably, α / β is 2 or greater. The average primary particle diameter is the maximum length value measured using the shape measurement function of the image analysis software WinROOF (Mitani Corporation).

[0058] By adjusting the α(Ag particles) / β(Ti particles) ratio to 2 or higher (meaning the silver nanoparticles are of a certain size), the transparency of the dispersion containing titania-coated silver can be well maintained. In the case of titania-coated silver, the α(Ag) / β(Ti) ratio is more preferably adjusted to 2 to 1,000, even more preferably to 2 to 100, and particularly preferably to 2 to 20.

[0059] Coverage of Ag particles Titania-coated silver is a material in which a portion of the surface of Ag (silver) particles is coated with Ti particles (titania). Titania-coated silver has a structure in which Ti particles are supported around Ag particles (carriers), or a structure in which Ti particles coat the Ag particles (carriers).

[0060] Similar to the measurement of the number of Ti particles, the area of ​​Ag particles and Ti particles are measured using the shape measurement function of the image analysis software WinROOF (Mitani Corporation). Let A be the area of ​​the Ag particle domain, and B be the area of ​​the Ti particle domain that overlaps with the Ag nanoparticles. Based on this, the coverage rate is defined as B(Ti particles) / A(Ag particles) × 100(%).

[0061] When Ag particles are completely covered by Ti particles, the coverage is 100% surface area. When Ag particles exist alone, the coverage is 0%, meaning the Ag particles are not covered by Ti particles.

[0062] In titania-coated silver, preferably, 5% to 95% of the surface of Ag particles (silver nanoparticles) is coated with Ti particles (titania). The coating value of titania-coated silver is preferably 10% to 90% of the surface, and more preferably 20% to 80% of the surface.

[0063] If the coverage of titania-coated silver exceeds 95% surface area, the exposure rate of Ag particles decreases, potentially reducing its antiviral performance. If the coverage of titania-coated silver is less than 5% surface area, the stability of Ag particles in the titania-coated silver or in the dispersion may decrease. By adjusting the coverage (B(Ti particles) / A(Ag particles) × 100(%)) between 5% and 95% surface area, titania-coated silver exhibits good antibacterial and antiviral activity, and dispersions containing titania-coated silver have good dispersion stability.

[0064] [2] Titania-coated silver-containing composition The present invention encompasses a titania-coated silver-containing composition comprising (A) titania-coated silver, (B) a Si compound, and (C) a solvent, wherein (B) the Si compound is a hydrolysis product of an alkoxysilane.

[0065] Titania-coated silver-containing compositions can improve adhesion to substrates by mixing titania-coated silver with a Si compound (binder). Titania-coated silver-containing compositions are materials that possess transparency, adhesion to substrates, durability, antibacterial and antiviral properties (antibacterial agent), and long-term stability by undergoing hydrolysis of alkoxysilane in the coexistence of titania-coated silver.

[0066] (2-1)(A) Titania-coated silver The titania-coated silver-containing composition of the present invention contains the titania-coated silver (A) of the present invention. Regarding the titania-coated silver (A), the above [1](A) Titania-coated silver Apply the explanation.

[0067] From the viewpoint of ease of coating and good coating film properties, the content of Ti particles contained in (A) titania-coated silver in the titania-coated silver composition is preferably 0.01% to 5% by mass.

[0068] (2-2)(B)Si compounds (Si binders) The titania-coated silver composition of the present invention contains a (B)Si compound, the (B)Si compound being a hydrolysis product of an alkoxysilane.

[0069] The titania-coated silver composition contains Ti particles (titania particles, Ti compounds), and the dispersibility of the Ti particles can be improved by applying organic matter to the fine titania surface.

[0070] By mixing Ti particles with a Si compound (alkoxysilane) that serves as a binder raw material, and allowing the two to coexist, a hydrolysis reaction can be carried out while maintaining high dispersibility, thereby producing a Ti particle composite binder.

[0071] The titania-coated silver-containing composition can improve titania aggregation, significantly improving solvent stability and adhesion.

[0072] Si compounds are hydrolysis products of alkoxysilanes (alkylsilanes).

[0073] Preferably, the alkoxysilane used is a monoalkoxysilane, dialkoxysilane, trialkoxysilane, tetraethoxysilane, or the like.

[0074] The monoalkoxysilane is preferably trimethylmethoxysilane, trimethylethoxysilane, or the like.

[0075] Dialkoxysilanes are preferably dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, diisobutyldimethoxysilane, dimethoxymethyl-n-octylsilane, and more preferably dimethyldimethoxysilane, dimethyldiethoxysilane, and the like.

[0076] Trialkoxysilanes are preferably methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltriisopropoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltripropoxysilane, n-propyltriisopropoxysilane, isopropyltrimethoxysilane, isopropyltrimethoxysilane, isopropyl Tripropoxysilane, n-butyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, etc. are used, and more preferably methyltrimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, etc. are used.

[0077] The tetraalkoxysilane is preferably tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, etc., and more preferably tetraethoxysilane (tetraethyl orthosilicate, Si(OC2H5)4, TEOS), tetramethoxysilane, etc.

[0078] The Si compound may be at least one compound selected from the group consisting of alkylsilanes, and these alkylsilanes may be used individually or two or more may be mixed (blended) depending on the purpose.

[0079] In the titania-coated silver-containing composition, preferably, the (B)Si compound is a hydrolysis product of tetraethyl orthosilicate (TEOS).

[0080] From the viewpoint of ease of coating and good coating film properties, the titania-coated silver-containing composition preferably contains 0.01% to 20% by mass of (B)Si compound.

[0081] (2-3)(C) Solvent The titania-coated silver-containing composition of the present invention contains (C) a solvent.

[0082] The titania-coated silver-containing composition preferably includes (C) water and alcohol as solvents.

[0083] The alcohols are preferably aliphatic alcohols having 1 to 6 carbon atoms such as methanol, ethanol, propanol, and isopropanol, and non-aliphatic alcohols such as α-terpineol; glycol solvents such as butyl carbitol (diethylene glycol monobutyl ether), hexylene glycol (2-methyl-2,4-pentanediol), ethylene glycol-2-ethylhexyl ether, ethylene glycol monomethyl ether, and propylene glycol monomethyl ether; and diols such as 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol.

[0084] The solvent preferably includes water, and the alcohol may be at least one compound selected from the group consisting of the aforementioned alcohols. These alcohols may be used individually or mixed (blended) with two or more depending on the purpose.

[0085] In the titania-coated silver-containing composition of the present invention, the solvent can also be changed. Water may be removed from the reaction solution by centrifugation, filtration, etc., and replaced with an organic solvent.

[0086] (2-4) Titania-coated silver-containing composition From the viewpoint of ease of coating and film properties of the coating, the ratio of Ti particles to Si compound in the titania-coated silver-containing composition is preferably such that Ti particles are present in a mass ratio of 0.02 to 20 parts by mass (0.02 to 20 parts by mass) per part by mass of Si compound, and more preferably 0.1 to 1 part by mass (0.1 to 1 part by mass) per part of Si compound.

[0087] The pH of the titania-coated silver-containing composition (dispersion) varies depending on the type and amount of metal added. From the viewpoint of coatability, the pH is preferably 1 to 5, and more preferably 2 to 4.

[0088] In titania-coated silver-containing compositions, the dispersibility of Ti particles (titania particles) can be improved by applying organic matter to the fine titania surface. By mixing Ti particles with a Si compound (alkoxysilane) that serves as a binder raw material, and performing a hydrolysis reaction while maintaining high dispersibility through the coexistence of both, a Ti particle composite binder can be produced.

[0089] Titania-coated silver-containing compositions can improve the aggregation of Ti particles (titania), significantly improving the solvent stability of paints and the adhesion of the coating film. Due to their good dispersibility, titania-coated silver-containing compositions exhibit excellent crack resistance in the coating. They also enable dense titania coatings, offering excellent applicability, transparency, and visible photocatalytic activity.

[0090] [3] Antibacterial and antiviral coating liquid (dispersion), paint, and coating film The present invention encompasses an antibacterial and antiviral coating liquid containing the titania-coated silver-containing composition of the present invention, and a paint containing the antibacterial and antiviral coating liquid of the present invention.

[0091] The titania-coated silver-containing composition allows for the preparation of a coating solution with excellent transparency, adhesion to the substrate, and solvent stability by using Ti particles (titanium dioxide) having organic chains on their surface and reacting them with a Si compound in a sol-gel reaction. Using this coating solution, photocatalytic titanium dioxide can be effectively immobilized on the substrate, enabling the formation of a superior coating layer on the article.

[0092] A dispersion containing a titania-coated silver composition is preferably prepared as a paint by adjusting its viscosity according to its intended use. When used for coating by spin coating, dip coating, spraying, etc., the viscosity is preferably adjusted to a low level. When used for coating by brush application, squeegeeing, etc., the viscosity is preferably adjusted to a higher level. When used for coating by screen printing, the viscosity is preferably adjusted to an even higher level to suppress fluidity.

[0093] An antibacterial and antiviral coating film (coating) formed by a paint containing an antibacterial and antiviral coating liquid enables a dense coating.

[0094] Painted products having a coating are not particularly limited. Examples of painted products having a coating include building materials, building exteriors, building interiors, window frames, window glass, various lenses, structural members, building equipment such as houses, cooking utensils, textile products, furniture, displays, display protective films, plumbing components, covers and window glass for vehicle lighting, machinery or exteriors of articles, dust covers and coatings, display devices and their covers, traffic signs, various display devices, advertising towers and other display objects, sound barriers for roads and railways, bridges, guardrail exteriors and coatings, tunnel interiors and coatings, insulators, solar cell covers, solar water heater collector covers and other exterior parts of electronic and electrical equipment used outdoors, especially transparent members, vinyl greenhouses, greenhouses and the like.

[0095] [4] Method for producing titania-coated silver-containing composition The method for producing the titania-coated silver-containing composition of the present invention is as follows: (1) A step of synthesizing Ti particles in a solvent and attaching organic chains to the Ti particles, (2) After step (1), a step of producing titania-coated silver, and (3) After step (2), the process includes mixing the titania-coated silver, to which organic chains are attached, with the Si compound in a solvent, and hydrolyzing the Si compound.

[0096] The method for producing the titania-coated silver composition of the present invention is preferably, (4) After step (3), the process includes a step of performing a high-pressure dispersion treatment to disperse the dispersion containing titania-coated silver.

[0097] Titania-coated silver is a material in which a portion of the surface of Ag (silver) particles is coated with Ti particles (titania).

[0098] (4-1)(1) A step of synthesizing Ti particles in a solvent and attaching organic chains to the Ti particles. In step (1), organic chains are bonded to the surface of Ti particles in a solvent. In step (1), organic matter is applied to the surface of fine Ti particles to improve the dispersibility of the Ti particles.

[0099] Ti particles (titanium-containing substances) are preferably substances that become titanium oxide upon heating. The titanium-containing substances are preferably titanium oxide and / or titanium oxide precursors, and more preferably titanium halides such as titanium oxide, titanium hydroxide, titanium alkoxide, titanium trichloride, titanium tetrachloride (especially those neutralized with a base), and metallic titanium.

[0100] From the viewpoint of the dispersibility, coatability, and visible photocatalytic properties of the resulting titania, the titanium-containing substance is preferably titanium alkoxide, titanium hydroxide, or titanium halide (especially those neutralized with a base). From the viewpoint of purity, dispersibility, coatability, transparency, and visible photocatalytic properties, the titanium-containing substance is more preferably titanium alkoxide.

[0101] The titanium alkoxide is preferably titanium tetraisopropoxide, titanium tetra-n-butoxide, titanium tetra-n-propoxide, or titanium tetraethoxide. From the viewpoint of cost, water solubility of by-products, applicability, and visible photocatalytic properties, titanium tetraisopropoxide is more preferable.

[0102] The Ti particles may be at least one compound selected from the group consisting of the aforementioned Ti particles, and these Ti particles may be used individually or two or more may be mixed (blended) depending on the purpose.

[0103] The average primary particle diameter of the Ti particles is preferably 100 nm or less, and more preferably 50 nm or less. There is no specific lower limit set for the average primary particle diameter of the titanium-containing material, but it is preferably about 1 nm. If the particle diameter is large, it is preferably ground dry or wet using a planetary ball mill, paint shaker, etc.

[0104] The average primary particle size of Ti particles (solids such as titanium oxide and metallic titanium) is measured by electron microscopy (TEM) observation.

[0105] The concentration of Ti particles in the dispersion is preferably 0.01 mol / L to 5 mol / L, and more preferably 0.05 mol / L to 3 mol / L, from the viewpoint of productivity, viscosity of the reaction solution, coatability, transparency, visible photocatalytic properties, etc.

[0106] In step (1), an acid is preferably used, and more preferably an organic acid. The acid is preferably a volatile acid with chemical formula C n H 2n+1 Monocarboxylic acids represented by COOH(n=0~3) (monocarboxylic acids with 1 to 4 carbon atoms), hydroxycarboxylic acids with 2 to 3 carbon atoms, etc. are used.

[0107] From the viewpoint of volatility, toxicity, and degradability, the monocarboxylic acids are preferably formic acid with n=0 and acetic acid with n=1.

[0108] The hydroxycarboxylic acid is preferably glycolic acid, lactic acid, etc., and more preferably acetic acid, glycolic acid, lactic acid, etc., from the viewpoint of water solubility and odor.

[0109] The organic acid may be at least one compound selected from the group consisting of the aforementioned organic acids, and these organic acids may be used individually or mixed (blended) with two or more depending on the purpose.

[0110] The lower limit of the amount of organic acid used is preferably adjusted so that the number of moles of acyloxy groups per mole of titanium in the Ti particles is 1.5 moles or more, and particularly preferably 2 moles or more, from the viewpoint of dispersibility, coatability, transparency, visible photocatalytic properties, and cost. The more organic acid used, the better the long-term stability, coatability, transparency, etc. can be improved. The upper limit of the amount of organic acid used is preferably adjusted so that the number of moles of acyloxy groups per mole of titanium in the Ti particles is 10 moles or less.

[0111] The concentration of the organic acid in the dispersion is preferably 0.02 mol / L to 10 mol / L, and more preferably 0.1 mol / L to 7 mol / L, from the viewpoints of dispersibility, coatability, transparency, visible photocatalytic properties, and cost.

[0112] The reaction solvent is preferably an aqueous solvent such as water, mainly composed of (preferably 50% by mass or more). The reaction solvent may also contain alcohol or ester during the reaction.

[0113] When titanium tetraisopropoxide is used as the reaction solvent, isopropyl alcohol is produced by reaction with organic acids. Isopropyl esters of organic acids may be produced by heating. Alcohols or esters may be added to the dispersion, or they may be generated in the system. Alcohols or esters may be removed by heating in an open system below 100°C, by reducing the pressure, or they may remain in the reaction solution.

[0114] When alcohol is present in the dispersion, the average primary particle size of the resulting Ti particles (titania nanoparticles) tends to decrease. Therefore, alcohol may be intentionally added to control the average primary particle size.

[0115] From the viewpoint of preventing corrosion of the equipment, ensuring safety during handling, and maintaining dispersibility, the pH of the dispersion is preferably between 2 and 6, and more preferably between 2.1 and 5.

[0116] The method for preparing the dispersion is not particularly limited; the Ti particles, organic acid, and water (solvent) may be mixed simultaneously or sequentially. In mass production, from the viewpoint of preventing aggregation and the formation of large clumps, and facilitating continued stirring, it is preferable to mix the organic acid and water (solvent) first, and then add the titanium-containing substance while stirring. In laboratory scale, it is preferable to mix the titanium-containing substance and the organic acid first, and then add the water while stirring.

[0117] (4-2)(2) After step (1), a process for producing titania-coated silver. In step (2), after step (1), the composite of Ti particles and Ag particles (silver compounds) is irradiated with ultraviolet light to produce titania-coated silver. In titania-coated silver, a portion of the surface of the Ag particles is coated with Ti particles. Titania-coated silver has a structure in which Ti particles are supported around Ag particles (carriers), or a structure in which Ti particles coat the Ag particles (carriers).

[0118] High-pressure dispersion method (pressure treatment) The production of Ti particles (titania compounds) preferably involves a dispersion process using a dispersion apparatus that generates high pressure through collisions between particles to disperse them (high-pressure dispersion method). By using a jet mill or the like, the Ti particles can be highly dispersed in a liquid, making it possible to partially coat Ag particles with Ti particles.

[0119] The dispersion containing Ti particles is subjected to a pressure treatment of 30 MPa or higher. This pressure treatment causes the Ti particles to become finer.

[0120] The pressure level during the pressurization process is not particularly limited, as long as it is sufficient to adequately atomize the Ti particles. Preferably, the pressure level is adjusted to 30 MPa or higher, more preferably to 50 MPa to 400 MPa, and even more preferably to 100 MPa to 300 MPa. The pressurization process is preferably carried out using a high-pressure dispersion device. A high-pressure dispersion device can disperse Ti particles by applying mechanical pressure.

[0121] By pressurizing, for example, (i) Colliding two or more dispersions of Ti particles with each other. (ii) Colliding a dispersion of Ti particles with a metal or ceramic material (high-hardness material such as silicon carbide or alumina), (iii) A dispersion of Ti particles with a cross-sectional area of ​​1 cm² 2 Passing through the following space Perform processes such as those described above.

[0122] By applying pressure, it is possible to increase the pressure conditions, which allows for more efficient atomization of Ti particles and further reduces processing time.

[0123] The pressurization operation is preferably performed once or more times, and more preferably 10 times or more.

[0124] The pressurizing temperature is not particularly limited. The pressurizing temperature is adjusted to a temperature that allows for sufficient thinning of the carbonaceous material having a layered structure. The pressurizing temperatures in (i) and (ii) are preferably adjusted to 0°C to 100°C, and more preferably to 20°C to 95°C. When mechanically applying pressure, the pressurizing temperature in (iii) is preferably adjusted to 0°C to 100°C. When pressure is generated by a supercritical state of water, the pressurizing temperature in (iii) is preferably adjusted to 373°C to 700°C, and more preferably to 380°C to 450°C.

[0125] When performing pressurized treatment, it is preferable to perform ultrasonic dispersion treatment on the dispersion containing Ti particles as a preliminary treatment (pretreatment) to atomize the Ti particles. This can have effects such as preventing clogging in high-pressure dispersion devices, supercritical water production devices, etc.

[0126] The output power during ultrasonic dispersion treatment is not particularly limited. From the viewpoint of atomizing Ti particles, the output power during ultrasonic dispersion treatment is preferably adjusted to be stronger than that of typical ultrasonic dispersion treatment (approximately 40W to 50W). The output power of the ultrasonic dispersion treatment is preferably adjusted to 100W or more, more preferably to 300W to 20,000W, and even more preferably to 400W to 18,000W.

[0127] The ultrasonic dispersion temperature is not particularly limited. Preferably, the ultrasonic dispersion temperature is adjusted to a temperature that allows for sufficient atomization of Ti particles. Preferably, the ultrasonic dispersion temperature is adjusted to 0°C to 80°C, and more preferably to 10°C to 70°C.

[0128] The ultrasonic dispersion time is not particularly limited. Preferably, the ultrasonic dispersion time is adjusted to a time that allows for sufficient atomization of the Ti particles. Preferably, the ultrasonic dispersion time is adjusted to 1 minute to 600 minutes, and more preferably to 3 minutes to 120 minutes.

[0129] As a pretreatment or posttreatment for pressurized treatment and ultrasonic dispersion treatment, other dispersion treatments using dispersive devices such as conventional mechanical stirring, dispersion using an emulsifier, or dispersion using a bead mill may be used in combination.

[0130] UV light irradiation Ultraviolet light irradiation is preferably carried out at room temperature (below 20°C), more preferably at 15°C or below, from the viewpoint of ease of supporting silver on Ti particles (titania nanoparticles), visible photocatalytic activity, reaction rate, productivity, controllability of aspect ratio, resistance to discoloration during low-intensity UV irradiation, visibility during high-intensity UV irradiation, and re-transparency in UV-free environments. The lower limit of the UV light irradiation temperature is not particularly limited, but is preferably 0°C when reacting at atmospheric pressure.

[0131] When irradiating with ultraviolet light, stirring is preferably performed to ensure that the dispersion and the silver salt react sufficiently. The method of stirring is not particularly limited and can be done according to conventional methods.

[0132] The reaction time for ultraviolet light irradiation is preferably 1.5 hours or more, and more preferably in the range of 1.5 hours to 36 hours. By adjusting the reaction time to 1.5 hours or more, the Ti particles are well supported around the Ag particles, and gelation of the Ag particles does not occur. By adjusting the reaction time to within 36 hours, the average primary particle size of the Ag particles is adjusted, and precipitation of Ag particles does not occur.

[0133] From the viewpoint of ease of loading, reaction rate, reaction controllability, and productivity, an ultraviolet irradiation device containing wavelengths of 280 nm to 500 nm is preferably used. By adjusting the wavelength of the ultraviolet light to a range of 280 nm or higher, the dispersion stability of titania-coated silver is good. By adjusting the wavelength of the ultraviolet light to a range of 500 nm or lower, the silver is well reduced and silver nanoparticles are well generated.

[0134] When using silver salts as Ag particles (silver compounds), the silver salts are preferably acidic or neutral in aqueous solution. Preferably, the silver salts used are silver(I) chloride, silver(I) nitrate, silver organic acids (silver(I) lactate, silver(I) acetate, silver(I) citrate, silver(I) myristate, etc.), silver(I) sulfide, silver(I) oxide, silver(I) phosphate, silver(I) carbonate, silver(I) bromide, silver(I) iodide, etc.

[0135] The silver salt may be at least one compound selected from the group consisting of the aforementioned silver salts, and these silver salts may be used individually or mixed (blended) with two or more depending on the purpose.

[0136] The amount of silver salt used is preferably 50% by mass or less relative to the titanium oxide in the Ti particles (titania nanoparticles), more preferably 0.01% to 40% by mass, and even more preferably 0.01% to 25% by mass, based on the mass of silver element in the silver salt, from the viewpoint of dispersibility, transparency, antimicrobial activity (antimicrobial activity and antiviral activity), and stability of Ti particles (titania nanoparticles). By adjusting the amount of silver salt used within this range, the titania-coated silver can easily maintain its coatability and transparency, and its antimicrobial activity, antiviral activity, and photocatalytic activity in the dark can be particularly improved.

[0137] The titania-coated silver may further contain at least one metal selected from the group consisting of copper and platinum.

[0138] Titania-coated silver can be recovered by conventional methods such as precipitation and centrifugation. The organic chains are bonded to titanium atoms on the surface, and titania-coated silver has a structure in which Ti particles are supported around Ag particles (supporters), or a structure in which Ti particles coat the Ag particles (supporters).

[0139] (4-3)(3) After step (2), the process involves mixing the titania-coated silver with the organic chain bonded to it with the Si compound in a solvent and hydrolyzing the Si compound. In step (3), after step (2), the titania-coated silver with organic chains attached is mixed with a Si compound in a solvent, and the Si compound is hydrolyzed (preparation of coating solution). In step (3), the Ti particles and the Si compound (alkoxysilane) which will be the raw material for the binder are mixed, and the hydrolysis reaction is carried out while maintaining high dispersibility through the coexistence of the two, thereby producing a Ti particle composite binder.

[0140] Hydrolysis is preferably carried out by covering the dispersion with a lid to prevent the solvent from evaporating and maintaining the dispersion at a temperature of about 65°C for about 15 hours.

[0141] Hydrolysis is preferably carried out under normal pressure or under pressure in a sealed container.

[0142] From the viewpoint of preventing corrosion of the equipment, ensuring safety during handling, and maintaining dispersibility, the pH of the dispersion is preferably 2 or higher and less than 6, and more preferably 2.1 to 5.

[0143] In titania-coated silver, organic substances (acetyl groups, acetoxy groups, etc.) bound to the surface of Ti particles (titania) react with Si compounds (alkylsilanes such as TEOS), and the hydrolysis of the Si compound proceeds (hydrolyzed alkylsilane products), resulting in a transparent coating solution.

[0144] (4-4)(4) After step (3), a high-pressure dispersion treatment is performed to disperse the dispersion containing titania-coated silver. In step (4), after step (3), a high-pressure dispersion treatment is performed to disperse the dispersion containing titania-coated silver. By performing a high-pressure dispersion treatment on the coating solution (high-pressure dispersion method), a transparent dispersion can be obtained.

[0145] The present invention provides a method for producing a titania-coated silver-containing composition that, by using a novel process to produce a composition containing Ti particles, can improve the aggregation of Ti particles, which has been a problem in the past, and can significantly improve solvent stability and adhesion. [Examples]

[0146] The present invention will be specifically described below with reference to examples.

[0147] The present invention is not limited to the following specific embodiments.

[0148] [1] Preparation of titania-coated silver-containing composition Tables 1-3 show the composition (components and content) of titania-coated silver and titania-coated silver-containing compositions.

[0149] [Example 1] (Step 1) Method for preparing photocatalytic titanium dioxide 140 g of titanium tetraisopropoxide was mixed with 60 g of acetic acid and stirred. Then, water was added until the total volume reached 800 g, and the mixture was stirred for 90 minutes. Subsequently, the mixture was heated to 75°C and stirred with a hot stirrer for 2 hours to obtain a homogeneous titania sol. The obtained sol was subjected to ultrasonic dispersion for 30 minutes to obtain a transparent titania sol.

[0150] The TG-DTA of the obtained titania sol was measured after heating it to 600°C under an air atmosphere at a rate of 3°C / min. The mass loss rate above 200°C was 10% by mass. This mass loss rate above 200°C is due to organic matter derived from acetic acid bound to the titania surface. To adjust the concentration of the obtained titania sol, it was diluted with water to obtain a titania sol with a TiO2 concentration of 2% by mass (wt%).

[0151] (Step 2) Dispersion treatment (high-pressure dispersion method, pressurized treatment) The obtained titania sol was dispersed using a dispersion device that generates high pressure through collisions between particles. Dispersion was performed using a jet mill or the like to obtain a well-dispersed titania sol.

[0152] (Step 3) Compounding with metal ions To the titania sol prepared as described above, with a TiO2 concentration of 2% by mass, silver nitrate was added so that the weight ratio of Ag / TiO2 was 0.05, and the mixture was thoroughly stirred until the whole was homogeneous. Next, the titania sol was irradiated with an ultraviolet lamp for 24 hours to reduce the silver nitrate and obtain a silver-compound titania sol.

[0153] (Step 4) Preparation of coating solution To 300 g of the 2% by mass silver-compound titania sol prepared as described above, 12 g of tetraethyl orthosilicate (TEOS) and 438 g of 1-propanol were added. The reactor was then covered to prevent the solvent from evaporating, and the mixture was maintained at 60°C for 12 hours. The organic matter bound to the titania surface reacted with tetraethyl orthosilicate, and the hydrolysis of tetraethyl orthosilicate proceeded, yielding a transparent coating solution. The resulting solution was subjected to high-pressure dispersion treatment (high-pressure dispersion method) to obtain a transparent dispersion.

[0154] [Example 2] The coating solution was prepared using the same process as in Example 1, except that in step 3 of Example 1, the irradiation time of the ultraviolet light lamp was changed to 12 hours.

[0155] [Example 3] The coating solution was prepared using the same process as in Example 1, except that in Step 1 of Example 1, the heating temperature of the hot stirrer was changed to 90°C and the reaction time to 8 hours.

[0156] [Example 4] The coating solution was prepared using the same process as in Example 1, except that in Step 1 of Example 1, the heating temperature of the hot stirrer was changed to 90°C and the reaction time to 12 hours.

[0157] [Example 5] The coating solution was prepared using the same process as in Example 1, except that in Step 1 of Example 1, the heating temperature of the hot stirrer was changed to 80°C and the reaction time to 12 hours, and in Step 3, the irradiation time of the ultraviolet light lamp was changed to 96 hours.

[0158] [Example 6] The coating solution was prepared using the same process as in Example 1, except that in Step 1 of Example 1, the heating temperature of the hot stirrer was changed to 90°C and the reaction time to 12 hours, and in Step 3, the irradiation time of the ultraviolet light lamp was changed to 240 hours.

[0159] [Example 7] The coating solution was prepared using the same process as in Example 1, except that in Step 1 of Example 1, the heating temperature of the hot stirrer was changed to 90°C and the reaction time to 12 hours, and in Step 3, the irradiation time of the ultraviolet light lamp was changed to 96 hours.

[0160] [Example 8] The coating solution was prepared using the same process as in Example 1, except that in Step 1 of Example 1, the heating temperature of the hot stirrer was changed to 90°C and the reaction time to 24 hours, and in Step 3, the irradiation time of the ultraviolet light lamp was changed to 48 hours.

[0161] [Example 9] The coating solution was prepared using the same process as in Example 1, except that in step 3 of Example 1, the ultraviolet light lamp was changed to 120 hours.

[0162] [Example 10] The coating solution was prepared using the same process as in Example 1, except that in step 4 of Example 1, 150 g of tetraethyl orthosilicate (TEOS) and 300 g of 1-propanol were used.

[0163] [Example 11] The coating solution was prepared using the same process as in Example 1, except that in step 4 of Example 1, 3.75 g of silver-compound titania sol was replaced with 0.075 g of tetraethyl orthosilicate (TEOS) and 746.2 g of 1-propanol.

[0164] [Comparative Example 1] Comparative Example 1 was prepared using the same process as in Example 1, except that the antibacterial agent Bactekiller powder manufactured by Fuji Chemical Co., Ltd. was adjusted to 2.0% by mass with distilled water to obtain a silver-supported oxide slurry, and then 2.4 g of tetraethyl orthosilicate and 267.6 g of 1-propanol were added to 30 g of the prepared 2% by mass silver-supported oxide slurry.

[0165] [Comparative Example 2] Comparative Example 2 involved adding 25.5 g of ethanol, 15 g of pure water, 0.55 g of MKC silicate MS51 manufactured by Mitsubishi Chemical Corporation, 22.5 g of aluminum chelate D (ethanol dilution: solid content concentration 1 wt%), 9 g of Emarex 715 manufactured by Nippon Emulsion Co., Ltd., and 1.5 g of sodium di(2-ethylhexyl) sulfosuccinate to a container and mixing. Then, 0.33 g of silver-supported glass bagtelite (solid content concentration 50 wt%) manufactured by Fuji Chemical Corporation was added and the mixture was stirred for 60 minutes to obtain an antibacterial solution.

[0166] [Comparative Example 3] Comparative Example 2 involved adding 25.5 g of ethanol, 15 g of pure water, 0.55 g of MKC silicate MS51 manufactured by Mitsubishi Chemical Corporation, 22.5 g of aluminum chelate D (ethanol dilution: solid content concentration 1 wt%), 9 g of Emarex 715 manufactured by Nippon Emulsion Co., Ltd., and 1.5 g of sodium di(2-ethylhexyl) sulfosuccinate to a container and mixing. Then, 0.65 g of silver-supported glass bagtelite (solid content concentration 50 wt%) manufactured by Fuji Chemical Corporation was added and the mixture was stirred for 60 minutes to obtain an antibacterial solution.

[0167] [2] Evaluation of titania-coated silver-containing compositions The following evaluations were performed on the obtained coating compositions of the examples and comparative examples.

[0168] (1) Transparency of the dispersion The transparency of the coating composition (dispersion) was measured by transmittance using a UV-Vis spectrometer (Shimadzu UV3400). The transmittance was defined as the highest transmittance value within the wavelength range of 400 nm to 800 nm.

[0169] The criteria for evaluating the dispersion are as follows: ◎: The dispersion has a maximum transmittance of 80% or higher. ○: The dispersion has a maximum transmittance of 50% or more. △: The dispersion has a maximum transmittance of 20% or more. ×: The dispersion has a maximum transmittance of less than 20%.

[0170] (2) Dispersibility (stability) of the dispersion The coating composition (dispersion) was allowed to stand at 60°C for 480 hours. After standing, the dispersion was visually inspected to evaluate its dispersion stability.

[0171] The criteria for evaluating the dispersion are as follows: ◎: No precipitation, gelation, or other phenomena are observed in the dispersion. ○: Separation is observed in the dispersion, but it disperses easily by stirring by hand. △: Separation is observed in the dispersion, but it can be redispersed by applying external force such as ultrasound. ×: Precipitation and gelation have occurred in the dispersion, and it will not redisperse.

[0172] (3) Adhesion of the coating film (dispersion) A coating film was prepared on a substrate using a coating composition (dispersion) by spin coating. The spin coating conditions were 2,000 rpm for 60 seconds. After confirming adhesion by touch, the adhesion of the coating film was evaluated according to the JIS K 5600_5_6 cross-cut test method.

[0173] The criteria for evaluating the coating are as follows: ◎: The coating film has a peeling rate of 5% or less from the substrate. ○: The coating film peels off the substrate by 20% or less. △: The coating film peels off the substrate by 50% or less. ×: The coating peels off from the substrate by more than 50%, or peels off when touched.

[0174] (4) Antiviral test After drying, the coating composition (dispersion) was subjected to an antiviral test in the dark using Qβ phage (non-enveloped virus) in accordance with ISO 21702.

[0175] The criteria for determining the antiviral properties of the dispersion are as follows: ◎: The dispersion has an antiviral activity value of 2 or higher. ×: The dispersion has an antiviral activity value of less than 2.

[0176] The results of the examples and comparative examples are shown in the table below.

[0177] [Table 1]

[0178] [Table 2]

[0179] [Table 3]

[0180] The titania-coated silver-containing compositions of Examples 1 to 11 exhibited excellent transparency, dispersion stability, adhesion when forming a coating film on a substrate, and antiviral properties as dispersions (coating agents).

[0181] The compositions containing silver-supported inorganic oxides in Comparative Examples 1-3 formed precipitates, changed to reddish-brown after standing, and gelled. The compositions in Comparative Examples 1-3 did not redisperse.

[0182] [Industrial applicability] The titania-coated silver of the present invention has a structure in which Ti particles are supported around Ag particles, that is, a structure in which Ti particles coat the Ag particles. The titania-coated silver-containing composition of the present invention contains a composite of fine titania-coated silver particles, and is a material that has high transparency, low silver aggregation, is stable, and can exhibit antiviral properties.

[0183] The titania-coated silver-containing composition of the present invention makes it possible to improve adhesion to a substrate by mixing titania-coated silver with a Si compound. The titania-coated silver-containing composition of the present invention is a material liquid (coating agent) that combines transparency, adhesion to a substrate, durability, antibacterial and antiviral properties (antibacterial agent), and long-term stability by hydrolyzing alkoxysilane in the coexistence of titania-coated silver.

Claims

1. Titania-coated silver, in which Ti particles are coated on the surface of Ag particles.

2. The titania-coated silver according to claim 1, wherein the titania-coated silver contains four or more Ti particles for every one Ag particle.

3. The titania-coated silver according to claim 1, wherein the titania-coated silver has a coating rate of 5% to 95%.

4. The titania-coated silver according to claim 1, wherein when the Ti particles are heated to 600°C using a thermogravimetric simultaneous thermometer, the mass loss at temperatures above 200°C is 1% by mass or more.

5. The titania-coated silver according to claim 1, wherein the Ti particles have an average primary particle diameter of 1 nm to 20 nm.

6. The titania-coated silver according to claim 1, wherein the Ag particles have an average primary particle diameter of 1 nm to 2,000 nm.

7. The ratio of the average primary particle diameter of the Ag particles to the average primary particle diameter of the Ti particles contained in the titania-coated silver is: (Average primary particle diameter of Ag particles / Average primary particle diameter of Ti particles) The titania-coated silver according to claim 1, wherein the coefficient is 2 to 100.

8. (A) Titania-coated silver according to any one of claims 1 to 7, (B) Si compounds, and (C) Contains a solvent, The (B)Si compound is a titania-coated silver-containing composition which is a hydrolysis product of an alkoxysilane.

9. The titania-coated silver-containing composition according to item 8, wherein the content of the Ti particles contained in the titania-coated silver (A) is 0.01% by mass to 5% by mass.

10. The titania-coated silver-containing composition according to claim 8, wherein the content of the (B)Si compound in the titania-coated silver-containing composition is 0.01% by mass to 20% by mass.

11. The titania-coated silver-containing composition according to claim 8, wherein the solvent (C) comprises water and alcohol.

12. The titania-coated silver-containing composition according to claim 8, wherein the (B)Si compound is a hydrolysis product of tetraethyl orthosilicate (TEOS).

13. An antibacterial and antiviral coating solution comprising the titania-coated silver-containing composition described in claim 8.

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