JP5590982B2 - Water-based coating composition and coating method using the same - Google Patents

Description

  The present invention relates to an aqueous coating composition and a coating method. In particular, the present invention relates to water-based coating compositions and coating methods used to coat the surface of various substrates.

Conventionally, a photocatalyst-supporting structure in which a photocatalyst is supported on a carrier mainly composed of organic substances such as plastics is known. By oxidative decomposition power by the photocatalyst and surface hydrophilization, dirt can be decomposed and removed by rainfall or washing with water. It is known that dirt can be washed away.
For example, Patent Document 1 discloses that a surface layer containing a photocatalytic oxide, silica, and a water-repellent fluororesin is provided on a substrate. Further, in Patent Document 2, an intermediate layer containing an organic antifungal agent is provided on a substrate, and photocatalyst particles, inorganic oxide particles, dried hydrolyzable silicone, elemental copper, and silver are formed on the intermediate layer. It is disclosed to provide a photocatalytic layer containing an element.
Also known is a coating agent in which a carrier such as inorganic fine particles or organic fine particles is mixed with a composition obtained by coating a metal having antibacterial and antifungal properties or a metal compound thereof by a sputtering method (see Patent Document 3). .

JP 2001-88247 A JP 2009-136868 A JP-A-8-239302

However, none of the layers and films formed by the above-described conventional techniques have an excellent antifouling effect even in an environment that is excellent in dirt adhesion suppressing effect and insufficient in light irradiation.
Accordingly, the present invention has been made to solve the above-described problems, and forms a coating film that has an excellent antifouling effect and an antifungal effect even in an environment where light irradiation is insufficient. It is an object of the present invention to provide an aqueous coating composition that can be used.

Accordingly, as a result of intensive studies to solve the conventional problems as described above, the present inventors have found that a specific water-soluble composition is contained in an aqueous coating composition in which inorganic particles and hydrophobic resin particles are dispersed in an aqueous medium. It discovered that what added the specific antifungal agent and water dispersible antifungal agent particle | grains by the specific ratio can solve the said subject, and came to complete this invention.
That is, the present invention is an aqueous coating composition in which inorganic particles and hydrophobic resin particles are dispersed in an aqueous medium, and is water-soluble with respect to the total mass of the inorganic particles and the hydrophobic resin particles. At least one water-soluble fungicidal agent selected from the group consisting of an organic iodine compound, a water-soluble isothiazoline compound and a water-soluble alanine compound, 1.0 mass% to 30 mass%, an imidazole compound, a triazole compound, a pyrithione compound, thiazole compounds and looking contains at least one 0.8% by weight of water dispersible fungicide particles above 25 wt% is selected from the group consisting of thiophene compounds, peroxides, perchloric acid, chlorate, in persulfate, aqueous coating composition further comprising at least one oxidizing agent selected from the group consisting of perphosphates and periodate That.
Moreover, this invention is a coating method characterized by apply | coating the said aqueous coating composition to a base material, and making it dry.

  In the coating film formed by the water-based coating composition of the present invention, hydrophilic and hydrophobic minute areas are exposed independently of each other, so that hydrophilic dirt and hydrophobic dirt adhere to each other. Can be prevented over a long period of time, and since a water-soluble antifungal agent component is present in the coating film, adhesion of mold spores can be suppressed, and further, a water dispersible antifungal agent in the coating film. Since the particles are dispersed, hyphal growth can be suppressed even when the hyphae germinate from the spores.

It is a figure for demonstrating the effect by the coating film formed with the water-system coating composition of this invention. It is a figure for demonstrating the adhesion mechanism of a dirt in a general anti-mold coating film, and the mechanism of mold generation.

Embodiment 1 FIG.
The water-based coating composition of the present invention contains inorganic particles, hydrophobic resin particles, a water-soluble fungicide, and water-dispersible fungicide particles as essential components. Hereinafter, each component will be described in detail.

<Water-soluble fungicides>
The water-soluble antifungal agent used in the present invention is a compound selected from the group consisting of an organic iodine compound, an isothiazoline compound and an alanine compound, as long as it dissolves easily in water. When such a water-soluble fungicide is blended, the fungicide component dissolves in the aqueous medium, and the fungicide component is dispersed over the entire surface when a coating film is formed.

  Specific examples of the water-soluble organic iodine compound include 3-iodo-2-propynylbityl carbamate, diiodomethyl-p-toluylsulfone, p-chlorophenyl-3-iodopropargyl formal, and the like. Specific examples of the water-soluble isothiazoline compound include 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, and 2-n-octyl-4-isothiazoline-3- ON, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, 2-methyl-4,5-trimethylene-4-isothiazolin-3-one, 1,2-benzisothiazolin-3-one , N-butyl-benzoisothiazolin-3-one, and the like. Specific examples of the water-soluble alanine compound include N-lauryl-β-alanine. These compounds may be used alone or in combination of two or more.

  The content of the water-soluble fungicide is 1.0% by mass or more and 30% by mass or less, preferably 2.0% by mass or more and 25% by mass or less, with respect to the total mass of the inorganic particles and the hydrophobic resin particles. It is. If the content is less than 1.0% by mass, the effect of suppressing mold cannot be sufficiently obtained. On the other hand, when the content exceeds 30% by mass, the antifouling performance is deteriorated and dirt easily adheres, and mycelia germinate from the attached dirt.

<Water-dispersible fungicide particles>
The water-dispersible fungicide particles used in the present invention are compounds selected from the group consisting of imidazole compounds, triazole compounds, pyrithione compounds, thiazole compounds and thiophene compounds, and can be dispersed in an aqueous medium. Good. The water-dispersible fungicide particles preferably have a water solubility at 20 ° C. of 0.5 mg / L or less. When the solubility exceeds 0.5 mg / L, the effect is limited in an environment where there is a lot of water, such as water parts. The average particle size of the water-dispersible fungicide particles is preferably 0.3 μm or more and 1.0 μm or less. When the average particle size is less than 0.3 μm, the effect of suppressing the growth of hyphae that germinate from spores attached to the coating film surface is poor. On the other hand, if the average particle size exceeds 1.0 μm, the unevenness of the coating film becomes too large and dirt is likely to adhere, and mold germination occurs from the dirt. In addition, the average particle diameter of the water dispersible antifungal agent particles used in the present invention is a value measured by ELSZ-2 manufactured by Otsuka Electronics Co., Ltd.

  Specific examples of the imidazole compound include 2- (4-thiazolyl) benzimidazole, 2-methoxycarbonylaminobenzimidazole, methyl 2-benzimidazolecarbamate, methyl 1- (butylcarbamoyl) -2-benzimidazolecarbamate, and thiabendazole. Etc. Specific examples of the triazole compound include 2- (4-chlorophenyl) -3-cyclopropyl-1- (1H-1,2,4-triazol-1-yl) -butan-2-ol, 4,4-dimethyl. -3- (1H-1,2,4-triazol-1-ylmethyl) pentan-3-ol and the like. Specific examples of the pyrithione compound include zinc pyrithione and sodium pyrithione. Specific examples of the thiazole compound include 2- (4-thiocyanomethylthio) benzothiazole. Specific examples of the thiophene compound include 3,3,4,4-tetrachlorotetrahydrothiophene-1,1-dioxide, 3,3,4-trichlorotetrahydrothiophene-1,1-dioxide, 3,3,4,4, and the like. -Tetrachlorotetrahydrothiophene-1,1-dioxide and the like. These compounds may be used alone or in combination of two or more.

  The content of the water-dispersible fungicide particles is 0.8% by mass or more and 25% by mass or less, preferably 1.0% by mass or more and 15% by mass with respect to the total mass of the inorganic particles and the hydrophobic resin particles. % Or less. If the content is less than 0.8% by mass, the effect of suppressing mold cannot be sufficiently obtained. On the other hand, if the content exceeds 25% by mass, the unevenness of the coating film becomes too large and dirt is likely to adhere, and mycelia germinate from the dirt.

  In the aqueous coating composition of the present invention, the water-soluble fungicide and the water-dispersible fungicide particles are preferably contained in a mass ratio of 50:50 to 98: 2, more preferably 60:40 to It is included at a mass ratio of 90:10. Within this range, the antifungal agent components are arranged in a well-balanced coating film and can exhibit excellent antifungal performance.

<Inorganic particles>
Although it does not specifically limit as an inorganic particle used by this invention, A silica, titania, an alumina, etc. are mentioned. Among these, silica is preferable. When silica fine particles are blended as inorganic particles of the aqueous coating composition of the present invention, there are various advantages. Silica has a refractive index close to that of plastic or glass compared to other inorganic particles such as titania and alumina. For this reason, when a coating film is formed, it is difficult to become white or glaring due to light reflection from the interface with the base or the surface. This effect can be further enhanced by the fact that silica is fine particles. The average particle size of the inorganic particles is preferably in the range of 5 to 15 nm when measured by a light scattering method (ELS-Z manufactured by Otsuka Electronics Co., Ltd.). In particular, the silica fine particles having such an average particle diameter are in a state in which the surface portion corresponding to about 15% by mass to 30% by mass of one silica fine particle is dissolved in water in the aqueous coating composition. ing. However, in the case of silica particles having an average particle size exceeding 15 nm, the proportion of the silica component in a state dissolved in water decreases as the average particle size increases. When the silica component dissolved in water is reduced, it becomes difficult to obtain the action as a binder, so the coating film that is formed does not have sufficient strength and cracks are likely to occur. It is not preferable. Therefore, it becomes necessary to separately add a binder to the aqueous coating composition. Conversely, in the case of silica particles having an average particle size of less than 5 nm, the proportion of the silica component in a state of being dissolved in water is increased in the aqueous coating composition. When the ratio of the silica component in a state of being dissolved in water is too large, silica particles are aggregated in the aqueous coating composition, making it difficult to obtain stability as a composition. Moreover, it becomes difficult to obtain desired coating film strength and antifouling performance.
The particle size of the silica fine particles also affects the appearance characteristics such as transparency of the coating film to be formed. If the silica fine particles have an average particle size of 15 nm or less, the scattering of light reflected by the coating film is reduced, so that the transparency of the coating film is improved and the color tone and texture of the substrate on which the coating film is formed are changed. It is possible to suppress the color tone and texture.
In addition, by using silica fine particles having an average particle size of 15 nm or less, the silica film in the resulting coating film is fine and has fine voids between the silica fine particles. Compared with conventional silica films that do not use fine particles formed by silicate or sol-gel methods, or silica films to which binders made of soluble organic or inorganic substances are added, the silica film can be formed thinner. Since the irregularities on the surface of the silica film due to the particles can be reduced and formed smoothly, dirt is not caught and the antifouling performance is improved.

  The content of the inorganic particles is preferably 0.1% by mass or more and 20% by mass or less, and more preferably 0.2% by mass or more and 10% by mass or less with respect to the aqueous coating composition. If the content is less than 0.1% by mass, the formed inorganic coating is too thin or sparse, and a good coating may not be obtained. On the other hand, if the content exceeds 20% by mass, the formed inorganic coating becomes too thick, cracks and the like may occur, and a good film may not be obtained.

<Hydrophobic resin particles>
The hydrophobic resin particles used in the present invention may be those dispersed in an aqueous medium, but a fluororesin is preferable. A mixture of fluororesin with other resins can also be used. Specific examples of the fluororesin include PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), ETFE (ethylene / tetra). Fluoroethylene copolymer), ECTFE (ethylene-chlorotrifluoroethylene copolymer), PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), PVF (polyvinyl fluoride), etc., and copolymers thereof Is mentioned. The hydrophobic resin particles preferably have a dispersion form stably dispersed in an aqueous medium due to the effect of a hydrophilic group contained in the surfactant or polymer. If it has the form of a dispersion, there also exists an advantage that the addition and stirring to a water-system coating composition are easy.
The average particle diameter of the hydrophobic resin particles used in the present invention is preferably 50 nm or more and 500 nm or less, more preferably 100 nm or more and 250 nm or less when measured by a light scattering method (ELS-Z manufactured by Otsuka Electronics Co., Ltd.). is there. Such an average particle diameter is preferable because it is sufficiently large with respect to the film thickness of the inorganic film portion of the coating film, so that the hydrophobic resin particles are moderately easily dispersed and easily exposed on the surface of the coating film. If the average particle size is less than 50 nm, the stability of the water-based coating composition may not be obtained, and the hydrophobic resin particles are not easily exposed on the surface in the formed coating film, and stable antifouling performance is obtained. It may not be possible. On the other hand, if the average particle diameter exceeds 500 nm, the hydrophobic region in the coating film to be formed becomes too large and hydrophobic dirt is likely to adhere, and the unevenness of the coating film becomes too large to cause dirt. In some cases, the desired antifouling performance may not be obtained due to being easily caught.

  The content of the hydrophobic resin particles is preferably 0.2% by mass or more and 5.0% by mass or less, more preferably 0.5% by mass or more and 3.0% by mass or less with respect to the aqueous coating composition. is there. If the content is less than 0.2% by mass, the antifouling effect may not be sufficiently obtained. On the other hand, if the content exceeds 5.0% by mass, the hydrophobic resin particles may aggregate when producing the aqueous coating composition, which is not preferable.

  In the aqueous coating composition of the present invention, the inorganic particles and the hydrophobic resin particles are preferably contained in a mass ratio of 20:80 to 95: 5, and more preferably in a mass ratio of 25:75 to 60:40. Included. If it is in this range, the coating film in which the hydrophilic region by the inorganic particles and the hydrophobic region by the hydrophobic resin particles coexist in a well-balanced manner can be easily obtained by drying at room temperature.

<Oxidizing agent>
When the base material on which the coating film is formed is a plastic, particularly polypropylene or polystyrene, which is difficult to coat, it is preferable to add an oxidizing agent to the aqueous coating composition.
The hydrophilic group formed by the decomposition of the surfactant present around the hydrophobic resin particles by the oxidizing agent enhances the binding action with the inorganic particles, preferably silica particles, and the interface existing around the hydrophobic resin particles. Since the hydrophobic group of the activator reinforces the binding action on the substrate side, it is possible to coat a substrate such as plastic that is difficult to coat.
The oxidizing agent used in the present invention is preferably water-soluble, and preferably has an organic substance decomposing action at room temperature. Examples of inorganic oxidants include inorganic peroxides that are metal salts of hydrogen peroxide, peroxides having a structure in which the hydroxy group (—OH) of oxo acid is replaced with a hydroperoxide group (—O—OH), and chlorine. Perchloric acids which are a kind of oxo acids, and persulfuric acids which are sulfur oxo acids. More specifically, as an inorganic oxidant, peroxides such as hydrogen peroxide, sodium peroxide, potassium peroxide, magnesium peroxide, calcium peroxide, barium peroxide, and peroxides such as ammonium persulfate and potassium persulfate are used. Perchlorates such as sulfuric acid, ammonium perchlorate, sodium perchlorate, potassium perchlorate, chlorates such as potassium chlorate, sodium chlorate, ammonium chlorate, calcium perphosphate, potassium perphosphate, etc. Periodic acid salts such as phosphoric acid, sodium periodate, potassium periodate, and magnesium periodate are listed. As an organic oxidant, a peroxide having a peroxide structure (—O—O—) as a functional group, a peroxide having a percarboxylic acid structure (—C (═O) —O—O—) as a functional group Etc. More specifically, as an organic oxidant, halogen benzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide, butyl hydroperoxide, peroxomonocarbonate, sodium peracetate, potassium peracetate, Examples include metachloroperbenzoic acid, tert-butyl perbenzoate, and percarboxylic acid.

  The content of the oxidizing agent is preferably 0.1 parts by mass or more and 30 parts by mass or less, and more preferably 2.0 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the hydrophobic resin particles. If the content is less than 0.1 part by mass, the effect of decomposing hydrophilic groups caused by the dispersant, surfactant, stabilizer, etc. present around the hydrophobic resin particles may not be sufficiently obtained. . On the other hand, when the amount exceeds 30 parts by mass, the amount of the oxidizing agent increases so that a desired amount of the hydrophobic resin particles and inorganic fine particles cannot be added, and the antifouling function may not be sufficiently exhibited.

  In addition, a surfactant may be added to the aqueous coating composition of the present invention for the purpose of improving the wettability of the aqueous coating composition to the surface of the substrate and the adhesion of the coating film.

<Method for producing aqueous coating composition>
The method for producing the aqueous coating composition of the present invention is not particularly limited. For example, adding a dispersion of inorganic particles, a dispersion of hydrophobic resin particles, a water-soluble fungicide, water-dispersible fungicide particles and, if necessary, an oxidizing agent to an aqueous medium and mixing. By this, the aqueous coating composition of the present invention can be produced.
The water contained in the water-based coating composition of the present invention is not particularly limited, but water having a small amount of ionic impurities such as calcium ions and magnesium ions is preferable for the dispersion stability of inorganic particles. The divalent or higher ionic impurity is desirably 200 ppm or less, and more desirably 50 ppm or less. If the amount of ionic impurities having two or more valences increases, inorganic particles (particularly silica fine particles) may aggregate and precipitate, and the strength and transparency of the formed coating film may be reduced. The water-based coating composition may be mixed with an organic solvent or the like in order to adjust the stability, applicability, and drying properties of the composition.

<Coating method>
The coating method of the present invention is not particularly limited and can be performed using a conventionally known method. When coating is performed by a dipping method or a coating method in which the surface of the substrate is covered with a liquid film of the aqueous coating composition, preferable results are easily obtained. In such a method, the surface of the substrate can be covered with an inorganic coating film without any defects. In order to obtain an inorganic coating with little unevenness, it is also preferable to remove excess aqueous coating composition with an air stream. In the case of the dipping method, it is desirable to slowly pull up the substrate from the aqueous coating composition to suppress unevenness of the liquid film due to the flow-down of the aqueous coating composition. In the case of the dipping method or the spray coating method, it is also preferable to remove the excess aqueous coating composition by centrifugal force, for example, by rotating the substrate. Also, spray coating may be preferred. The spraying method can be applied not only to substrates that are difficult to immerse or coat, but by adjusting the spraying conditions, fine irregularities can be formed on the inorganic coating, and the generation of interference colors due to the thin film can be suppressed. If it is desired to eliminate unevenness or increase the film thickness more reliably, the above coating can be repeated.

After applying the water-based coating composition, room temperature drying or heat drying is performed. In the case of drying at room temperature, it is also preferable to accelerate the drying with an air stream in order to shorten the drying time. When performing heat drying, it may be performed by blowing warm air or may be heated in a drying furnace. The purpose of the drying here is to eliminate the fluidity of the inorganic film-forming component forming a film. If necessary, heating is performed after drying. Heating may be performed also for drying. This heating is performed for the purpose of insolubilizing and curing the inorganic film-forming component and improving durability. When the inorganic film-forming component is insolubilized by drying at room temperature, or when it may take a long time to improve durability, heating can be omitted. If it is not heated, it takes a long time for the durability improvement effect to appear. It will take at least a few hours and weeks if it is long.
Heating can be performed using warm air, infrared rays, a heating furnace, or the like. The heating temperature is preferably 40 ° C. or higher and 90 ° C. or lower, and more preferably 45 ° C. or higher and 80 ° C. or lower. Below 40 ° C., there is an effect in a cold environment, but generally a clear effect cannot be obtained. When it exceeds 90 ° C., it is difficult to obtain the effect of improving durability. The heating time is preferably 10 minutes or more, and more preferably 30 minutes or more. When the heating time is less than 10 minutes, it is difficult to obtain the durability improvement effect.

Next, the function and effect of the coating film formed by the above-described coating method will be described with reference to the drawings.
FIG. 1 is a schematic diagram for explaining the function and effect of the coating film formed by the aqueous coating composition of the present invention. When the aqueous coating composition of the present invention is applied to the substrate 4, the water-dispersible fungicide particles 6, the inorganic particles 7 and the hydrophobic resin particles 8 are deposited on the substrate 4, and the water-soluble fungicide is The dissolved aqueous solution 5 covers the entire particles. In particular, when a surfactant is present on the surface of the hydrophobic resin particles 8 (when the surfactant is included in the aqueous coating composition), the aqueous solution 5 in which the water-soluble fungicide is dissolved is used as the surfactant. Since the water-soluble antifungal agent is present around the surfactant even after drying, the surfactant can be prevented from becoming a nutrient source for the mold 1. When the applied aqueous coating composition is dried to form a coating film, the hydrophilic microregions by the inorganic particles 7 and the hydrophobic microregions by the hydrophobic resin particles 8 are exposed independently of each other. Therefore, regardless of whether the dirt 2 is hydrophilic or hydrophobic, the adhesion of the dirt 2 can be prevented and the generation of mold 1 from the dirt 2 can be suppressed. Moreover, since the water dispersible antifungal agent particles 6 are dispersed in the aqueous coating composition with a constant particle size, they are uniformly dispersed when a coating film is formed by drying. Therefore, even when mold 1 (spore) adheres to the coating film, its growth can be suppressed. In addition, by using the water dispersible antifungal agent particles 6 having a solubility in water of 0.5 mg / L or less, the antifungal component is eluted in the water even in an environment where there is a large amount of water such as water parts. The generation of mold can be suppressed over a long period of time.

  FIG. 2 is a schematic diagram for explaining the mechanism of dirt adhesion and mold generation in a mold-proof coating film containing a general mold-proof component. In the anti-mold coating film containing the anti-mold component as shown in FIG. 2, the initial anti-mold performance can be exhibited, but when used for a long time, the hydrophilic or hydrophobic dirt 2 adheres, so the attached dirt. 2 causes mold 1 to occur. Further, when a surfactant is present on the surface of the mold-proof coating film, the surfactant becomes a nutrient source for mold 1 and the growth of mold is promoted.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to these.

<Example 1>
PTFE dispersion (produced by Asahi Glass Co., Ltd.) containing deionized water containing colloidal silica (produced by Nissan Chemical Industries, Ltd.) having an average particle diameter of 20 nm as inorganic particles and fluororesin having an average particle diameter of 550 nm as hydrophobic resin particles, Organic iodine compound as water-soluble antifungal agent (Amical (registered trademark) 48, manufactured by Angus Chemical Company), thiabendazole compound as water-dispersible antifungal agent particles having an average particle size of 0.5 μm (manufactured by EC Sea International) Then, after adding hydrogen peroxide as an oxidizing agent, the mixture was stirred and mixed to prepare an aqueous coating composition having the composition shown in Table 1.

<Example 2>
PTFE dispersion (manufactured by Asahi Glass Co., Ltd.) containing deionized water containing colloidal silica (manufactured by Nissan Chemical Industries, Ltd.) having an average particle diameter of 5 nm as inorganic particles, and a fluororesin having an average particle diameter of 250 nm as hydrophobic resin particles, Organic iodine compound as water-soluble antifungal agent (Amical (registered trademark) 48, manufactured by Angus Chemical Company), thiabendazole compound as water-dispersible antifungal agent particles having an average particle size of 0.5 μm (manufactured by EC Sea International) And after adding hydrogen peroxide as an oxidizing agent, the aqueous coating composition having the composition shown in Table 1 was prepared by stirring and mixing.

<Example 3>
PTFE dispersion (manufactured by Asahi Glass Co., Ltd.) containing deionized water containing colloidal silica (manufactured by Nissan Chemical Industries, Ltd.) having an average particle diameter of 10 nm as inorganic particles, and a fluororesin having an average particle diameter of 250 nm as hydrophobic resin particles, Organic iodine compound as water-soluble antifungal agent (Amical (registered trademark) 48, manufactured by Angus Chemical Company), thiabendazole compound as water-dispersible antifungal agent particles having an average particle size of 0.5 μm (manufactured by EC Sea International) And after adding hydrogen peroxide as an oxidizing agent, the aqueous coating composition having the composition shown in Table 1 was prepared by stirring and mixing.

<Example 4>
PTFE dispersion (produced by Asahi Glass Co., Ltd.) containing deionized water containing colloidal silica (produced by Nissan Chemical Industries, Ltd.) having an average particle diameter of 20 nm as inorganic particles and fluororesin having an average particle diameter of 550 nm as hydrophobic resin particles, Organic iodine compounds as water-soluble fungicides (Amical (registered trademark) 48, manufactured by Angus Chemical Company), thiabendazole compounds having an average particle size of 1.5 μm as water-dispersible fungicide particles (manufactured by EC Sea International) Then, after adding hydrogen peroxide as an oxidizing agent, the mixture was stirred and mixed to prepare an aqueous coating composition having the composition shown in Table 1.

<Example 5>
PTFE dispersion (manufactured by Asahi Glass Co., Ltd.) containing deionized water containing colloidal silica (manufactured by Nissan Chemical Industries, Ltd.) having an average particle diameter of 10 nm as inorganic particles, and a fluororesin having an average particle diameter of 250 nm as hydrophobic resin particles, Organic iodine compounds as water-soluble fungicides (Amical (registered trademark) 48, manufactured by Angus Chemical Company), thiabendazole compounds having an average particle size of 1.5 μm as water-dispersible fungicide particles (manufactured by EC Sea International) And after adding hydrogen peroxide as an oxidizing agent, the aqueous coating composition having the composition shown in Table 1 was prepared by stirring and mixing.

<Example 6>
PTFE dispersion (manufactured by Asahi Glass Co., Ltd.) containing deionized water containing colloidal silica (manufactured by Nissan Chemical Industries, Ltd.) having an average particle diameter of 10 nm as inorganic particles, and a fluororesin having an average particle diameter of 250 nm as hydrophobic resin particles, Organic iodine compounds as water-soluble fungicides (Amical (registered trademark) 48, manufactured by Angus Chemical Company), thiabendazole compounds having an average particle size of 1.5 μm as water-dispersible fungicide particles (manufactured by EC Sea International) And after adding hydrogen peroxide as an oxidizing agent, the aqueous coating composition having the composition shown in Table 1 was prepared by stirring and mixing.

<Example 7>
PTFE dispersion (manufactured by Asahi Glass Co., Ltd.) containing deionized water containing colloidal silica (manufactured by Nissan Chemical Industries, Ltd.) having an average particle diameter of 10 nm as inorganic particles, and a fluororesin having an average particle diameter of 250 nm as hydrophobic resin particles, Organic iodine compound as water-soluble antifungal agent (Amical (registered trademark) 48 manufactured by Angus Chemical Company), thiabendazole compound having an average particle size of 0.3 μm as water dispersible antifungal agent particles (manufactured by EC Sea International) And after adding hydrogen peroxide as an oxidizing agent, the aqueous coating composition having the composition shown in Table 1 was prepared by stirring and mixing.

<Comparative Example 1>
PTFE dispersion (produced by Asahi Glass Co., Ltd.) and deoxidized water containing colloidal silica (produced by Nissan Chemical Industries, Ltd.) having an average particle size of 30 nm as inorganic particles, and a fluororesin having an average particle size of 500 nm as hydrophobic resin particles After adding hydrogen peroxide as, a water-based coating composition having the composition shown in Table 1 was prepared by stirring and mixing.

<Comparative example 2>
Colloidal silica with an average particle size of 30 nm as inorganic particles (manufactured by Nissan Chemical Industries, Ltd.), organic iodine compound as a water-soluble antifungal agent (Amical (registered trademark) 48, manufactured by Angus Chemical Company), water dispersion in deionized water After adding a thiabendazole compound (manufactured by EC Sea International) having an average particle size of 0.3 μm as an anti-fungal agent particle and hydrogen peroxide as an oxidizing agent, the composition shown in Table 1 was obtained by stirring and mixing. An aqueous coating composition having was prepared.

<Comparative Example 3>
PTFE dispersion (manufactured by Asahi Glass Co., Ltd.) containing deionized water containing colloidal silica (manufactured by Nissan Chemical Industries, Ltd.) having an average particle diameter of 10 nm as inorganic particles, and a fluororesin having an average particle diameter of 250 nm as hydrophobic resin particles, Organic iodine compounds as water-soluble fungicides (Amical (registered trademark) 48, manufactured by Angus Chemical Company), thiabendazole compounds having an average particle size of 1.5 μm as water-dispersible fungicide particles (manufactured by EC Sea International) Then, after adding hydrogen peroxide as an oxidizing agent, the mixture was stirred and mixed to prepare an aqueous coating composition having the composition shown in Table 1.

  The aqueous coating compositions of Examples 1 to 7 and Comparative Examples 1 to 3 were applied to a plastic substrate (polystyrene), and a coating film was formed by blowing off excess aqueous coating composition by air blowing. Thereafter, the antifouling performance and antifungal performance of the coating film were evaluated.

<Evaluation of antifouling performance>
The antifouling performance was evaluated for the adhesion of sand dust as a hydrophilic fouling substance and the carbon dust as a hydrophobic fouling substance.
Adhesion of hydrophilic fouling substances is measured by spraying JIS Kanto Loam dust with a central particle size of 1 to 3 μm onto the coating film with air, and then collecting with a mending tape (Sumitomo 3M Co., Ltd.). Absorbance (wavelength 550 nm) by Shimadzu Corporation UV-3100PC) was measured and evaluated according to the following criteria.
1: Absorbance is less than 0.1.
2: Absorbance of 0.1 or more and less than 0.2.
3: Absorbance of 0.2 or more and less than 0.3.
4: Absorbance of 0.3 or more and less than 0.4.
5: Absorbance of 0.4 or more.

Hydrophobic fouling substances can be fixed by spraying oil-based carbon black onto the coating film with air, then collecting with a mending tape (manufactured by Sumitomo 3M Co., Ltd.) and spectrophotometer (UV-3100PC manufactured by Shimadzu Corporation). ) (Wavelength 550 nm) was measured and evaluated according to the following criteria.
1: Absorbance is less than 0.1.
2: Absorbance of 0.1 or more and less than 0.2.
3: Absorbance of 0.2 or more and less than 0.3.
4: Absorbance of 0.3 or more and less than 0.4.
5: Absorbance of 0.4 or more.

<Evaluation of mold prevention performance>
The mold prevention performance was carried out by a mold resistance test. The plastic substrate on which the coating film was formed was placed on a glucose-added inorganic salt agar medium. A total of 50 μL of mold spore solution (black mold) was spread on the substrate at 4 to 5 locations, and spread with a sterilized cotton swab moistened with sterilized water. Further, about 100 μL of mold spore solution (black mold) was placed on the end face of the substrate in contact with the agar medium. This was cultured at 25 ° C. for 8 weeks, and mold growth with time was observed.

Further, after spraying dust equivalent to 10 years on the surface of the test piece, a mold resistance test was carried out in the same manner as described above.
Evaluation in this test was performed according to the following criteria.
0: No mold growth was observed with the naked eye or under a microscope.
1: Mold growth is not observed with the naked eye, but can be confirmed under a microscope.
2: The growth of mycelia is slight and the area of the growth part does not exceed 25% of the total area of the sample.
3: The growth of the mycelium is moderate, and the area of the growth part is 25% or more and less than 50% of the total area of the sample.
4: Mycelium grows well, and the area of the growth part is 50 to less than 100% of the total area of the sample.
5: Mycelium grows vigorously and covers the entire sample surface.

  Table 2 shows the evaluation results of antifouling performance and antifungal performance.

  From the experimental results shown in Table 2, the coating films formed by the aqueous coating compositions of Examples 1 to 7 exhibit excellent antifouling performance against both hydrophilic and hydrophobic fouling substances, and are resistant to mold. Excellent antifungal performance was exhibited by adjusting the content and blending ratio of the water-soluble organic iodine compound and thiabendazole compound for the test. In addition, it showed excellent antifungal performance in a mold resistance test after spraying dirt for 10 years. In particular, the coating film formed by the aqueous coating composition of Example 2 was most excellent in antifouling performance and antifungal performance. This is the most excellent for both hydrophilic and hydrophobic fouling substances, so even when dust dirt equivalent to 10 years is sprayed, it is difficult for dirt to adhere, and even if dirt adheres, it is water-soluble organic. The iodine compound and thiabendazole compound sufficiently suppress the adhesion of spores and germination of mycelia. However, when the antifouling performance is limited as in Example 1 and Example 4, when dirt equivalent to 10 years is sprayed, the dirt adhesion suppressing effect cannot be obtained and the mold suppressing effect is limited. .

On the other hand, in Comparative Example 1, since the water-soluble organic iodine compound and the thiabendazole compound are not blended, the effect on the mold resistance test is not observed, and the mold prevention performance is significantly lowered. In Comparative Example 2, dust does not easily adhere because it does not contain hydrophobic resin particles having an antifouling performance effect, and the effect is considerably effective for a mold resistance test after spraying dust dirt equivalent to 10 years. It will decline.
In Comparative Example 3, since the water-soluble organic iodine compound and thiabendazole compound are excessively blended, the antifouling performance against both hydrophilic and hydrophobic fouling substances is limited. As a result, the effect is inferior to the mold resistance test after spraying dirt equivalent to 10 years, and the effect as a whole coating film is limited.

  DESCRIPTION OF SYMBOLS 1 Mold, 2 Dirt, 3 Antifungal layer, 4 Base material, 5 Water solution in which water-soluble antifungal agent was dissolved, 6 Water dispersible antifungal agent particle, 7 Inorganic particle, 8 Hydrophobic resin particle

Claims (8)

An aqueous coating composition in which inorganic particles and hydrophobic resin particles are dispersed in an aqueous medium,
1. at least one water-soluble fungicide selected from the group consisting of a water-soluble organic iodine compound, a water-soluble isothiazoline compound and a water-soluble alanine compound with respect to the total mass of the inorganic particles and the hydrophobic resin particles. 0% by mass or more and 30% by mass or less and at least one water-dispersible fungicide particle selected from the group consisting of imidazole compounds, triazole compounds, pyrithione compounds, thiazole compounds and thiophene compounds 0.8% by mass to 25% by mass percent and only contains the following,
An aqueous coating composition further comprising at least one oxidizing agent selected from the group consisting of peroxide, perchloric acid, chlorate, persulfuric acid, perphosphoric acid and periodate .   The water-dispersible fungicide particles have a water solubility at 20 ° C of 0.5 mg / L or less and an average particle size of 0.3 µm or more and 1.0 µm or less. 2. The aqueous coating composition according to 1.   The aqueous coating composition according to claim 1 or 2, wherein the inorganic particles and the hydrophobic resin particles are contained in a mass ratio of 20:80 to 95: 5.   The aqueous system according to any one of claims 1 to 3, wherein the water-soluble fungicide and the water-dispersible fungicide particles are contained in a mass ratio of 50:50 to 98: 2. Coating composition.   The water-based coating composition according to any one of claims 1 to 4, wherein the inorganic particles are silica particles having an average particle diameter of 5 nm or more and 15 nm or less.   The aqueous coating composition according to any one of claims 1 to 5, wherein the hydrophobic resin particles are fluororesin particles having an average particle diameter of 50 nm or more and 500 nm or less. The relative hydrophobic resin particles 100 parts by weight, according to any one of claims 1 to 6, wherein the oxidizing agent is added in an amount of less than 30 parts by mass or more 0.1 part by weight Water-based coating composition.   A coating method comprising applying the aqueous coating composition according to any one of claims 1 to 7 to a substrate and drying the substrate.

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