JP2022065439A - Photocatalyst composition, photocatalyst composition solution, photocatalyst member, method for using photocatalyst composition, and space-disinfecting method - Google Patents

Abstract

To provide a photocatalyst composition that exhibits strong photocatalyst effect with visible light, a photocatalyst composition including the photocatalyst composition, a photocatalyst member, a method for using the photocatalyst composition, and a space-disinfecting method.SOLUTION: A photocatalyst composition contains a compound having an isoalloxazine skeleton or alloxazine skeleton, and a sacrificial agent. The compound having an isoalloxazine skeleton or alloxazine skeleton contains at least one selected from riboflavin and riboflavin derivatives. The sacrificial agent contains at least one selected from ascorbic acids, polyols, polyphenols, and alkanolamines.SELECTED DRAWING: Figure 1

Description

The present invention relates to a photocatalyst composition, a photocatalyst composition solution, a photocatalyst member, a method of using the photocatalyst composition, and a method of space sterilization.

Photocatalysts that exhibit catalytic action by irradiating with light are known. Since photocatalysts can easily decompose organic substances and sterilize them simply by irradiating them with light, various applications are being studied.
Currently, titanium oxide is widely used as a photocatalyst. In order for titanium oxide to exhibit a catalytic action, it is necessary to irradiate it with ultraviolet light, and it has been pointed out that titanium oxide is carcinogenic, so its application may be limited. Therefore, photocatalysts applicable to various uses are being studied.

For example, in Patent Document 1, a reducing organic substance composed of ascorbic acid and a specific iron supply raw material are mixed at a specific ratio in the presence of water at 40 to 100 ° C. for 10 seconds to 10 days. A photocatalyst containing the reaction product containing the Fe ²⁺ complex of the reducing organic substance as an active ingredient is disclosed.

Further, Patent Document 2 discloses a method for sterilizing a polymer material, which comprises a step of applying a radioactive sensitizer to the polymer material and a step of irradiating the polymer material with suitable radiation at a dose and time effective for sterilizing the polymer material. It is described that 200 μg / mL or more of riboflavin is used as the radiation sensitizer.

Japanese Unexamined Patent Publication No. 2018-023977 Special Table 2010-508403 Gazette

An object of the present invention is to provide a photocatalytic composition capable of obtaining a strong photocatalytic effect with visible light, a photocatalytic composition using the photocatalytic composition, a photocatalytic member, a method of using the photocatalytic composition, and a method of space sterilization. Is.

The photocatalytic composition according to the present invention contains an isoaroxadin skeleton or a compound having an alloxazine skeleton, and a sacrificial agent.

In one embodiment of the photocatalyst composition, the isoaroxadin skeleton or the compound having an alloxazine skeleton includes a compound represented by the following general formula (1) or a compound represented by the following general formula (2).

式（１）中、
Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、各々独立に、水素原子、ハロゲン原子、又は、置換基を有していてもよい炭化水素基であり、
Ｒ^５及びＲ^６は、水素原子、若しくは、置換基を有していてもよい炭化水素基であり、
式（２）中、
Ｒ^１１、Ｒ^１２、Ｒ^１３及びＲ^１４は、各々独立に、水素原子、ハロゲン原子、又は、置換基を有していてもよい炭化水素基であり、
Ｒ^１５及びＲ^１６は、水素原子、若しくは、置換基を有していてもよい炭化水素基である。

In equation (1),
R ¹ , R ² , R ³ and R ⁴ are hydrocarbon groups which may independently have a hydrogen atom, a halogen atom, or a substituent, respectively.
R ⁵ and R ⁶ are hydrogen atoms or hydrocarbon groups which may have a substituent and may have a substituent.
In equation (2),
R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are hydrocarbon groups which may independently have a hydrogen atom, a halogen atom, or a substituent, respectively.
R ¹⁵ and R ¹⁶ are hydrogen atoms or hydrocarbon groups which may have a substituent.

In one embodiment of the photocatalytic composition, the sacrificial agent comprises one or more selected from ascorbic acids, polyols, polyphenols, and alkanolamines.

One embodiment of the photocatalytic composition comprises one or more selected from the riboflavin and the riboflavin derivative in which the isoaroxadin skeleton or the compound having the alloxazine skeleton is selected.

In one embodiment of the photocatalyst composition, the mass ratio (A / C) of the compound (A) having the isoaroxadin skeleton or the alloxazine skeleton and the sacrificial agent (C) is 1/10 to 1/200. ..

One embodiment of the photocatalytic composition further contains iron ions.

The present invention provides a photocatalytic composition solution containing the above photocatalytic composition and a solvent.
The present invention provides a photocatalyst member having a coating film containing the photocatalyst composition on a substrate.

One embodiment of the method of using the photocatalyst composition is
(I) Sacrifice to a composition solution containing the isoaroxadin skeleton or a compound having an alloxazine skeleton and a solvent, or (II) a member having a coating film containing the compound having the isoaroxadin skeleton or the alloxazine skeleton on a substrate. Supply the agent.

The present invention also provides a space sterilization method for spraying the photocatalytic composition into a space.

INDUSTRIAL APPLICABILITY The present invention provides a photocatalytic composition that can obtain a strong photocatalytic effect with visible light, a photocatalytic composition using the photocatalytic composition, a photocatalytic member, a method of using the photocatalytic composition, and a method of space sterilization.

It is a graph which shows the sustainability test result.

Hereinafter, the photocatalyst composition according to the present invention (hereinafter, also referred to as the present photocatalyst composition), the photocatalyst composition using the photocatalyst composition, the photocatalyst member, the method of using the photocatalyst composition, and the space sterilization method will be described in order. do.
Unless otherwise specified, "~" indicating the numerical range includes the lower limit value and the upper limit value.

[Photocatalytic composition]
The photocatalytic composition contains the isoaroxadin skeleton or a compound having an alloxazine skeleton, and a sacrificial agent. In this photocatalyst composition, the isoaroxadin skeleton or the compound having an alloxazine skeleton functions as a photosensitizer and supplies the electrons of the sacrificial agent to molecular oxygen via the excited photosensitizer to generate active oxygen. , Decomposes organic substances and has a bactericidal action. By using a compound having an isoaroxazine skeleton, it efficiently absorbs visible light (for example, a wavelength of 400 to 600 nm) and exhibits a photocatalytic effect. Further, by combining the sacrificial agent, an excellent photocatalytic effect can be obtained even when a light source having a relatively small output such as a white LED is used. Furthermore, by combining the above isoaroxadin skeleton or a compound having an alloxazine skeleton with a sacrificial agent, for example, when this photocatalytic composition is used in a solution, a photocatalytic effect can be obtained even at a low concentration, so that the color of the solution can be suppressed. It is possible.
The photocatalyst composition may contain at least the above-mentioned compound having an isoaroxadin skeleton or an alloxazine skeleton and a sacrificial agent, and may further contain other components as long as the effects of the present invention are exhibited. Hereinafter, each component that may be contained in the present photocatalyst composition will be described.

<Compounds having an isoaroxazine skeleton or an alloxazine skeleton>
The isoaroxazine skeleton or the compound having an alloxazine skeleton (hereinafter, also referred to as a compound having an isoaroxazine skeleton or the like) functions as a photosensitizer in which the isoaroxazine skeleton or the like absorbs visible light or the like.
In this photocatalytic composition, the compound having an isoaroxazine skeleton or the like is a compound represented by the following general formula (1) or a compound represented by the following general formula (2) from the viewpoint of obtaining an excellent photocatalytic action. Is preferable.

式（１）中、
Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、各々独立に、水素原子、ハロゲン原子、又は、置換基を有していてもよい炭化水素基であり、
Ｒ^５及びＲ^６は、水素原子、若しくは、置換基を有していてもよい炭化水素基であり、
式（２）中、
Ｒ^１１、Ｒ^１２、Ｒ^１３及びＲ^１４は、各々独立に、水素原子、ハロゲン原子、又は、置換基を有していてもよい炭化水素基であり、
Ｒ^１５及びＲ^１６は、水素原子、若しくは、置換基を有していてもよい炭化水素基である。

In equation (1),
R ¹ , R ² , R ³ and R ⁴ are hydrocarbon groups which may independently have a hydrogen atom, a halogen atom, or a substituent, respectively.
R ⁵ and R ⁶ are hydrogen atoms or hydrocarbon groups which may have a substituent and may have a substituent.
In equation (2),
R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are hydrocarbon groups which may independently have a hydrogen atom, a halogen atom, or a substituent, respectively.
R ¹⁵ and R ¹⁶ are hydrogen atoms or hydrocarbon groups which may have a substituent.

Examples of the halogen atom in R ¹ to R ⁴ and R ¹¹ to R ¹⁴ include a fluorine atom, a chlorine atom and a bromine atom.
The hydrocarbon group in R ¹ to R ⁴ and R ¹¹ to R ¹⁴ may have a linear or branched alkyl group having 1 to 6 carbon atoms and a linear or branched alkyl group as a substituent. Examples thereof include a cycloalkyl group or an aryl group having 6 to 12 carbon atoms. Examples of the linear or branched alkyl group include a methyl group, an ethyl group, an n-butyl group, a tert-butyl group, a hexyl group and the like. Examples of the cycloalkyl group include a cyclohexyl group. Examples of the aryl group include a phenyl group and a naphthyl group. Examples of the substituent that the hydrocarbon group in R ¹ to R ⁴ and R ¹¹ to R ¹⁴ may have include a hydroxy group, a carboxy group, a halogen atom and the like.
From the viewpoint of photocatalytic activity, it is preferable that R ¹ , R ⁴ , R ¹¹ and R ¹⁴ are independently hydrogen atoms. Further, from the viewpoint of photocatalytic activity, R ² , R ³ , R ¹² and R ¹³ are each independently preferably a linear or branched alkyl group having no substituent, and an alkyl group having 1 to 4 carbon atoms is more preferable. Preferably, a methyl group is even more preferred.

Examples of the hydrocarbon group in R ⁶ , R ¹⁵ and R ¹⁶ include the same groups as those in R ¹ and the like, and the preferred embodiment is also the same. From the viewpoint of photocatalytic activity, R ⁵ , R ¹⁵ and R ¹⁶ are preferably hydrogen atoms independently.

Examples of the hydrocarbon group in R ⁵ include the same groups as those in R ¹ and the like. Examples of the substituent that the hydrocarbon group in ^R5 may have include a hydroxy group or an ester thereof. As the substituent in R5, a ^ribityl group ( _-CH2 -CHOH-CHOH-CHOH- _CH2 OH) or an esterified form of the OH of the ribityl group is preferable.

Further, the compound having an isoaroxadin skeleton or an alloxazine skeleton is particularly preferably riboflavin or a riboflavin derivative. Riboflavin, also known as vitamin B2, is highly safe and can be suitably used, for example, in applications that may be taken up by humans or living organisms.
Specific examples of the riboflavin derivative include riboflavin tetrabutyrate, riboflavin tetraacetate, luminomy (7,8-dimethylaloxazine), riboflavin phosphate ester, and salts thereof (sodium salt, potassium salt, etc.), flavin adenine dinucleotide. And so on.

Among these, riboflavin and riboflavin derivatives are preferably riboflavin, riboflavin tetrabutyrate, luminome, and sodium riboflavin phosphate because of their photocatalytic activity, safety, and easy industrial availability.
In this photocatalyst composition, the compound having the isoaroxadin skeleton or the alloxazine skeleton can be used alone or in combination of two or more.

<Sacrifice>
In the present photocatalytic composition, the sacrificial agent refers to a compound that advances the reaction while being decomposed by itself in the photocatalytic reaction. When used in combination with the compound having an isoaroxazine skeleton or the like, an excellent photocatalytic effect can be obtained with visible light.

As the sacrificial agent, ascorbic acids, polyols, polyphenols, and alkanolamines are preferable because of their photocatalytic activity, safety, and easy availability in the industry. The sacrificial agent may be used alone or in combination of two or more.

Examples of ascorbic acids include ascorbic acid, isoascorbic acid (erythorbic acid) and salts thereof. The counter ion of the salt is not particularly limited, and examples thereof include lithium ion, sodium ion, potassium ion, calcium ion, magnesium ion, and iron ion.

Examples of the polyols include compounds having two or more hydroxy groups in one molecule, preferably three or more hydroxy groups in one molecule. Among them, a polyol having a composition formula of Cn H _{2n-2 On ( n} is an integer of 2 or more) and a polyether thereof are preferable because of their high electric power donating capacity. Specific examples of the polyol satisfying the composition formula include glycerin, threitol, arabitol, xylitol, ribitol and the like, and examples of the polyether include polyglycerin and the like. The polyols that are liquid at the operating temperature (for example, 25 ° C.) can also function as a solvent described later.

Examples of the polyphenols include compounds having two or more phenolic hydroxyl groups in one molecule, and the hydroxyl groups may be salts. As the polyphenols, naturally derived polyphenols are preferable because they have a low environmental load and high safety to the living body. Specifically, ferulic acid, tannic acid, catechinic acid, gallic acid epigallocatekin, gallic acid, chlorogenic acid, caffeic acid, ellagic acid, curcumin, lignan, rutin, hesperidin, kenferol, quercetin, isoflavone, anthocyanin, theaflavin. , Theaflavingalate, cyanidin, resveratrol, carconic acid, ellagic acid, kelcitrin, isokercitrin, myricitrin, mylicetin, delphinidin, Delphin, nasnin, peonidin, peonin, neohesperidin, hesperetin, naringin, lingenin, purnin, astragaline , Apiin, Apigeni, Dizein, Daijin, Glycytein, Glycytin, Genistane, Genistin, Malvidin, Malvin, Enin, Leucocianidin, Cyanin, Chrysantemin, Kerasianin, Idein, Mecocyanin, Pelargonidin, Calistefin, p-kumalic acid, Sesamine, Examples thereof include sesamolin and sodium salts, potassium salts, calcium salts and the like thereof, and one kind alone or two or more kinds can be used in combination.

Examples of alkanolamines include compounds having one or more hydroxy groups and one or more amino groups in one molecule, and acids and salts in which the amino group of the compound is an organic acid, an oxo acid, or the like. .. Specific examples of alkanolamines include triethanolamine, diethanolamine, ethanolamine, methanolamine, triisopropanolamine, diisopropanolamine, isopropanolamine, butylethanolamine, 2,2'-(cyclohexylimino) bisethanol, N-. Examples thereof include tert-butyldiethanolamine, dimethylaminoethanol, N-piperidinethanol, N-morpholinethanol, 2- (methylamino) ethanol, 2-[(hydroxymethyl) amino] ethanol and the like.
Examples of acids that form salts with alkanolamines include acetic acid, lactic acid, succinic acid, salicylic acid, citric acid, gluconic acid, tartaric acid, lactic acid, fumaric acid, malic acid, phosphoric acid, ascorbic acid, erythorbic acid, and malic acid. Organic acids such as oleic acid, phytic acid, octylphosphonic acid, and the like; oxo acids such as phosphoric acid, boric acid, sulfuric acid, nitric acid, polyphosphoric acid, silicic acid and the like.

Among these, the sacrificial agent is particularly preferably containing ascorbic acid because of its photocatalytic activity, safety, and easy industrial availability.

In this photocatalyst composition, the mass ratio (A / C) of the compound (A) having an isoaroxazine skeleton and the like and the sacrificial agent (C) is preferably 1/10 to 1/200. If the A / C is 1/200 or more, the photocatalytic effect is excellent. On the other hand, A / C is 1/10 or less and exhibits a sufficient photocatalytic effect. However, since the sacrificial agent decreases at the time of use, it may be added in excess in advance, and if the amount of the sacrificial agent decreases, it may be newly added. Further, when the liquid polyols also function as a solvent at the operating temperature, the A / C may be set to 1/10 or more, and a sufficient photocatalytic effect is exhibited in this case as well.

<Other ingredients>
The photocatalyst composition may further contain other components as long as the effects of the present invention are exhibited. Examples of other components include an iron compound as a source of iron ions, a copper compound as a source of copper ions, a nickel compound as a source of nickel ions, and a photocatalyst composition solution and a photocatalyst member described later. Each component is mentioned.
The photocatalyst composition preferably contains at least one selected from an iron compound, a copper compound, and a nickel compound.
This photocatalytic composition containing any of iron ion, copper ion, and nickel ion gives the electron of the sacrificial agent to the molecular oxygen via the photosensitizer excited by light to generate hydrogen peroxide. Further, the hydrogen peroxide causes a Fenton reaction to generate hydroxyl radicals, so that more excellent decomposition action and bactericidal action of organic substances can be obtained. The photocatalyst composition preferably contains iron ions.

When combining iron ions, a dissociative iron compound may be added to the photocatalyst composition. The iron compound may contain divalent iron ions or may contain trivalent iron ions. This is because iron ions repeat a divalent state and a trivalent state in a photocatalytic reaction.
Examples of the iron compound include iron (II) chloride, iron (II) sulfate, iron (II) nitrate, iron (II) hydroxide, iron (II) oxide, iron (II) acetate, iron (II) lactate, and quen. Iron (II) acid sodium, iron (II) gluconate, iron (II) carbonate, iron (II) fumarate; iron (III) chloride, iron (III) sulfate, iron (III) citrate, iron citrate (II) III) Ammonium, EDTA iron (III), iron oxide (III), iron nitrate (III), iron hydroxide (III), iron pyrophosphate (III), iron ascorbate (II) and the like can be mentioned. In addition, iron (II) ascorbic acid has both a source of iron ions and a function of the sacrificial agent.
When iron ions are used, it is preferable that the photocatalytic composition contains water to such an extent that the iron compound dissociates during the photocatalytic reaction.

The mass ratio (B / C) of the iron compound (B), which is the source of the iron ions, and the sacrificial agent (C) is not particularly limited, but is 1/40 to 1 / from the viewpoint of excellent photocatalytic effect. It is preferably 200.

[Photocatalytic composition solution]
The photocatalyst composition solution contains the photocatalyst composition and a solvent.
As the solvent, an appropriate solvent can be selected from those that dissolve or disperse each component of the photocatalyst composition. From the viewpoint that each component of the photocatalyst composition can be dissolved, the solvent preferably contains one or more solvents selected from water and a water-soluble solvent, and more preferably contains water. Examples of the water-soluble solvent include alcohol-based solvents such as ethanol, isopropanol, propylene glycol, and glycerin. In addition, polyols such as propylene glycol and glycerin can also function as the sacrificial agent.
When a mixed solvent of water and a water-soluble solvent is used, the water-soluble solvent is preferably 10% by mass or less, preferably 5% by mass or less, based on 100% by mass of the solvent. Further, the solvent is preferably a solvent consisting substantially only of water, since it can be used for various purposes.

The ratio of the isoaroxadin skeleton or the compound having an alloxazine skeleton in the photocatalyst composition solution is preferably 1 to 100 μg / mL, more preferably 2 to 80 μg / mL, and further preferably 5 to 50 μg / mL based on the volume of the solution. preferable. By setting it to the above lower limit value or more, excellent photocatalytic performance is exhibited. On the other hand, when the value is not more than the above upper limit, a photocatalyst composition solution with suppressed coloring can be obtained. When the photocatalyst composition solution to be colored is used, there is a problem that the light transmission becomes insufficient and the photocatalytic effect may not be obtained in a portion away from the light source. By suppressing the coloring of this photocatalyst composition solution, the problem that light does not reach even when used in a large amount can be suppressed. It is also suitable when it is desired to visually recognize the inside of the photocatalyst composition solution.

The ratio of the sacrificial agent in the solution of the photocatalyst composition is preferably 5 to 2000 μg / mL, more preferably 10 to 1500 μg / mL, still more preferably 15 to 1200 μg / mL based on the volume of the solution. Within the above range, a solution having an excellent photocatalytic effect can be obtained. Since the sacrificial agent is consumed, it may be temporarily out of the above range. If the proportion of sacrificial agent is low, it may be added as appropriate.

When iron ions are used, the ratio of iron ions in the solution of the photocatalyst composition is preferably 0.01 to 10 μg / mL, more preferably 0.02 to 5 μg / mL, and 0.1 to 0.1, based on the volume of the solution. It is more preferably ~ 2 μg / mL. When the value is 0.01 μg / mL or more, the effect of iron ions is fully exhibited and the solution has an excellent photocatalytic effect.

The photocatalyst composition solution may further contain other components depending on the intended use and the like, as long as the effects of the present invention are exhibited. Examples of other components include surfactants, antifoaming agents, preservatives, pH adjusters and the like.
Surfactants are used for the purpose of imparting wettability to a substrate or the like, and are known interfaces such as anionic surfactants, nonionic surfactants, and cationic surfactants, depending on the application. It can be appropriately selected from the activators and used.

This photocatalyst composition solution can be applied to any conventionally known application in which a photocatalyst is used. Furthermore, since this photocatalyst composition solution is highly safe even if it is taken into the body of humans or living organisms, for example, purification of water in the tank of an air purifier or a humidifier; space removal by spraying into a space such as a room. Uses for fungi; water in aquariums for breeding aquatic organisms; water for growing plants and the like.

[Photocatalyst member]
The photocatalyst member includes a coating film containing the photocatalyst composition on a substrate.
The base material may be appropriately selected from base materials such as resin, non-woven fabric, metal, glass, and ceramics according to the use of the member. When a resin or the like that may be deteriorated due to the photocatalytic effect is used as a base material, a silicone film may be provided as an undercoat layer before forming the film of the photocatalytic composition.

The film of the photocatalyst composition may further contain other components depending on the intended use and the like, as long as the effect of the present invention is exhibited. As other components, each component exemplified in the photocatalyst composition solution or a binder resin may be contained.
Adhesion to the substrate is improved by using the binder resin. As the binder resin used in the photocatalyst member, an aqueous organic resin is preferable. Specific examples thereof include water-based urethane resin, water-based acrylic resin, water-based polyester resin, water-based epoxy resin, water-based fluororesin, water-based silicone resin, and water-based polyethylene resin.
The film of the photocatalyst composition can be formed, for example, by spraying the photocatalyst composition, the photocatalyst composition solution, or a mixture thereof with the binder resin onto the surface of the substrate.

This photocatalytic member can be suitably used, for example, as a building material such as an outer wall of a building, a window glass, an indoor floor material, a wallpaper, or a filter having photocatalytic performance by using a porous base material.

[How to use the photocatalytic composition]
As an example of how to use this photocatalyst composition,
(I) A composition solution containing an isoaroxadin skeleton or a compound having an alloxazine skeleton and a solvent, or (II) a member having a coating film containing a compound having an isoaroxadin skeleton or an alloxazine skeleton on a substrate.
There is a method of supplying the sacrificial agent.

According to the above method of use, the sacrificial agent is supplied to the composition solution or the member in which the sacrificial agent is reduced, and the photocatalytic performance can be easily regenerated. In the case of a solution, the sacrificial agent or the sacrificial agent is supplied by adding the sacrificial agent solution. In the case of a member, the sacrificial agent or the sacrificial agent solution is sprayed onto the film to supply the sacrificial agent.

As described above, this photocatalytic composition absorbs visible light by combining a compound having an isoaroxazine skeleton or an alloxazine skeleton with a sacrificial agent, and obtains an excellent photocatalytic effect even at a low concentration. Be done. Since it can be used at a low concentration, it can be dispersed even in the form of an aqueous solution in which coloring is suppressed, for example. In addition, since each component is excellent in safety to living organisms, it can be suitably used for applications that are likely to be taken into living organisms.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Hereinafter, "ppm" represents "μg / mL".

[Example 1: Preparation of photocatalytic composition solution]
Water was added to 10 parts by mass of riboflavin, 100 parts by mass of sodium L-ascorbate, and 10 parts by mass of iron (II) gluconate to prepare the photocatalytic composition solution of Example 1 so as to have the concentration shown in Table 1. Got

[Examples 2 to 18: Preparation of photocatalytic composition solution]
Photocatalytic composition solutions of Examples 2 to 18 were obtained in the same manner as in Example 1 except that each component and the blending amount were changed to the concentrations shown in Tables 1 to 3 in Example 1.

[Comparative Examples 1 to 12: Preparation of solution]
Solutions of Comparative Examples 1 to 12 were obtained in the same manner as in Example 1 except that the respective components and blending amounts were changed to the concentrations shown in Tables 1 to 3 in Example 1.
The "iron ascorbic acid complex" in the table was synthesized according to the description of Example 3 of Japanese Patent Application Laid-Open No. 2018-023977 (Patent Document 1 above).

[evaluation]
<Evaluation of bactericidal properties>
After preparing the indigenous bacteria collected from an ultrasonic humidifier to a predetermined concentration, add to an autoclave-sterilized ordinary bouillon medium (Eiken Chemical Co., Ltd., Eiken (registered trademark)) and shake at 30 ° C. and 120 rpm. The cells were shake-cultured in an incubator for 24 hours, and the cells in which the number of bacteria reached about 1.5 × ¹⁰⁹ CFU / ml were used as the seeding solution.
Separately, the photocatalytic composition solutions obtained in the above Examples and Comparative Examples were also autoclaved.
The seeding bacterial solution was diluted with the photocatalytic composition solutions of the Examples and Comparative Examples, respectively, to prepare a bacterial count of 1.5 × ¹⁰⁷ CFU / ml, which was used as a test solution.
Two similar examples were prepared for each example and comparative example, stored under the following two conditions, and then the bacterial count was measured using "Sunny Check BF" (manufactured by Bio-Sun Laboratories), and the following was performed. It was evaluated according to the evaluation criteria. The results are shown in Tables 1 to 3.
(1) Under the condition of 25 ° C., a white LED (FHF32W2; manufactured by Sanyo Electric Co., Ltd.) was used as a light source, and irradiation was performed at a photon flux density of 20.25 μmol · m ⁻² · s ^-1 for 2 hours.
(2) Stored in a dark place for 2 hours under the condition of 25 ° C.
(Evaluation criteria)
⊚: The number of bacteria was 0 to 1.0 × 10 ³ CFU / ml or less.
◯: The number of bacteria was 1.0 × 10 ³ CFU / ml or more and less than 1.0 × 10 ⁴ CFU / ml.
Δ: The number of bacteria was 1.0 × 10 ⁴ CFU / ml or more and less than 1.0 × 10 ⁶ CFU / ml.
X: The number of bacteria was 1.0 × 10 ⁶ CFU / ml or more and 1.5 × 10 ⁷ CFU / ml or less.

<Coloring evaluation>
A predetermined amount of each photocatalyst composition obtained in Examples and Comparative Examples in a spray bottle was sprayed on a standard test cloth cut into 5 cm × 5 cm from a position 10 cm away, and used as an evaluation sample before and after application. The color difference represented by the following formula was measured. The results are shown in Tables 1 to 3.
Standard cloth: Crecia Techno Wipe C100-M Nippon Paper Crecia Co., Ltd. Color difference ΔE = [(ΔL) ² + (Δa) ² + (Δb) 2] ^1/2
ΔL = L value (after application) -L value (before application)
Δa = a value (after application) -a value (before application)
Δb = b value (after application) -b value (before application)

[Summary of Tables 1 to 3]
As shown in Comparative Example 3, the iron ascorbic acid complex of Patent Document 1 did not have a sufficient bactericidal effect with the current light source having a low photon flux density. As shown in Comparative Example 4, a slightly bactericidal effect can be obtained at a concentration of 1%, but the high concentration makes it impractical to use, for example, for water in aquariums for breeding aquatic organisms.
The solution of Comparative Example 11 containing an isoaroxazine skeleton or a compound having an alloxazine skeleton and not containing a sacrifice did not have a sufficient bactericidal effect. The present inventors have found that there is a certain degree of bactericidal effect when the sodium riboflavin phosphate is separately set to 10,000 ppm, but as shown in the evaluation of the colorability of Comparative Example 11, riboflavin phosphate A solution containing 200 ppm of sodium ester was confirmed to be clearly colored, and it became clear that it would be a problem when used for visually recognizing the inside of the solution.
As shown in Examples 1 to 18, this photocatalytic composition containing an isoaroxadin skeleton or a compound having an alloxazine skeleton and a sacrificial agent has an excellent bactericidal effect while suppressing the concentration of the compound having an isoaroxadin skeleton or the like. It became clear that

[Examples 19 to 27]
Photocatalytic composition solutions of Examples 19 to 27 were obtained in the same manner as in Example 1 except that each component and the blending amount were changed to be parts by mass shown in Table 4 in Example 1. The numerical values of each component in Table 4 indicate parts by mass.
The obtained photocatalyst composition was evaluated for bactericidal property and colorability by the same method as the above-mentioned evaluation method. The results are shown in Table 4.

As shown in Table 4, the photocatalytic composition of Examples 20 to 22 in which the mass ratio (A / C) of the compound (A) having an isoaroxadin skeleton and the like and the sacrificial agent (C) is 1/10 to 1/200. The compound was shown to be particularly excellent in photocatalytic effect.
Further, the photocatalytic compositions of Examples 24 to 26 having a mass ratio (B / C) of 1/40 to 1/200 of the iron compound (B) and the sacrificial agent (C) are particularly excellent in photocatalytic effect. Was shown to be.

<Evaluation of bactericidal activity sustainability>
Three 100 ml photocatalyst composition solutions of Example 2 and 100 ml of purified water were prepared for comparison, and the seeding bacterial solution prepared at 1.0 × 10 ³ CFU / ml, respectively, was prepared every 24 hours. 1 mL each was added, and the number of bacteria was measured immediately before adding the inoculum solution. The photocatalyst composition solution of Example 2 was stored and operated under the following conditions (1) to (3). Purified water was stored under the condition of (2) below. The results are shown in FIG.
(1) Under the condition of 25 ° C., a white LED (FHF32W2; manufactured by Sanyo Electric Co., Ltd.) was used as a light source, and light irradiation was continued at a photon flux density of 20.25 μmol · m ^-2 · s ^-1 .
(2) Stored in a dark place under the condition of 25 ° C.
(3) Light irradiation was continued under the conditions of (1) above, and 20 ppm of Na ascorbic acid was added every 24 hours.

As shown in FIG. 1, the photocatalytic composition of Example 2 was able to suppress the increase in the number of bacteria for up to about 5 days. It was also clarified that the photocatalytic effect can be maintained for a long period of time by adding the sacrificial agent every 24 hours.

[Example 28]
A photocatalytic resin composition was prepared by blending a polyurethane coating agent (manufactured by Yushiro Chemical Industry Co., Ltd., RB6) with riboflavin 100 ppm, sodium erythorbate 1000 ppm, and an iron compound 5 ppm.
The photocatalytic resin composition was applied onto a petri dish and dried to form a film containing the catalyst composition.
The obtained film was spray-irradiated with 0.5 ml of a bacterial solution having a bacterial count of 1.0 × ¹⁰⁷ CFU / ml. Then, blue light having a wavelength of 450 nm and 1000 lpx was irradiated for 2 hours.
The film after irradiation was stamped using SAN-AI EZ-DipTTC (manufactured by San-Ai Oil Co., Ltd.), and the number of bacteria was measured.
In addition, as a control experiment, a polyurethane-based coating agent (RB6) was used instead of the photocatalytic resin composition, and the number of bacteria was measured in the same manner as above.
The number of bacteria on the coating without the photocatalytic composition was approximately 1.0 × 10 ⁴ CFU / ml, whereas the number of bacteria on the coating of Example 28 was less than 1.0 × 10 ³ CFU / ml. there were. As described above, it was shown that this photocatalyst composition can obtain a bactericidal effect even when it is combined with a binder resin to form a film.

[Comparative Examples 1 to 13 : Preparation of Solution]
Solutions of Comparative Examples 1 to 13 were obtained in the same manner as in Example 1 except that the respective components and blending amounts were changed to the concentrations shown in Tables 1 to 3 in Example 1.
The "iron ascorbic acid complex" in the table was synthesized according to the description of Example 3 of Japanese Patent Application Laid-Open No. 2018-023977 (Patent Document 1 above).

Claims (10)

A photocatalytic composition containing an isoaroxadin skeleton or a compound having an alloxazine skeleton and a sacrificial agent. The photocatalytic composition according to claim 1, wherein the isoaroxadin skeleton or the compound having an alloxazine skeleton comprises a compound represented by the following general formula (1) or a compound represented by the following general formula (2).

In equation (1),
R ¹ , R ² , R ³ and R ⁴ are hydrocarbon groups which may independently have a hydrogen atom, a halogen atom, or a substituent, respectively.
R ⁵ and R ⁶ are hydrogen atoms or hydrocarbon groups which may have a substituent and may have a substituent.
In equation (2),
R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are hydrocarbon groups which may independently have a hydrogen atom, a halogen atom, or a substituent, respectively.
R ¹⁵ and R ¹⁶ are hydrogen atoms or hydrocarbon groups which may have a substituent. The photocatalytic composition according to claim 1 or 2, wherein the sacrificial agent comprises one or more selected from ascorbic acids, polyols, polyphenols, and alkanolamines. The photocatalytic composition according to any one of claims 1 to 3, wherein the isoaroxadin skeleton or the compound having an alloxazine skeleton contains at least one selected from riboflavin and a riboflavin derivative. Any one of claims 1 to 4, wherein the mass ratio (A / C) of the compound (A) having the isoaroxadin skeleton or the alloxazine skeleton to the sacrificial agent (C) is 1/10 to 1/200. The photocatalytic composition according to the section. The photocatalytic composition according to any one of claims 1 to 5, further comprising iron ions. A photocatalytic composition solution containing the photocatalytic composition according to any one of claims 1 to 6 and a solvent. A photocatalyst member comprising a film containing the photocatalyst composition according to any one of claims 1 to 6 on a substrate. (I) A composition solution containing an isoaroxadin skeleton or a compound having an alloxazine skeleton and a solvent, or (II) a member having a coating film containing a compound having an isoaroxadin skeleton or an alloxazine skeleton on a substrate.
How to use a photocatalytic composition to supply a sacrificial agent. A space sterilization method for spraying the photocatalytic composition according to any one of claims 1 to 6 into a space.

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