JPH101402A - Antibacterial and antimycotic coating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating agent capable of forming an antibacterial and antimycotic film having thin thickness, a smooth surface and excellent transparency by dissolving an antibacterial agent or an antimycotic agent at a specific concentration in a specific silica sol solution. SOLUTION: This coating agent is a solution comprising (A) a silica sol solution containing 0.5-2.5wt.% of silica sol reduced to SiO2 and having <=10cps viscosity, prepared by hydrolyzing and condensing (i) a hydrolyzable organic silane compound with (ii) an acid catalyst selected from hydrochloric acid and nitric acid in an amount of satisfying the formula: 0.004<=[H]/[Si]<=0.100 in the presence of (iii) water in an amount of satisfying the formula: 1.2<=[H2 O]/[Si]<=10.0 in which (B) at least one kind of organic agent selected from an antibacterial agent and an antimycotic agent in an amount of 0.05-1wt.% is dissolved. The [H] is a molar amount of the acid catalyst, [Si] is a molar amount of the hydrolyzable organic silane compound and [H2 O] is a molar amount of the water. By the composition, the coating agent exhibits high hardness and adhesiveness, and its effect is expected to be continued.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is applied to a substrate such as glass, metal, and plastic, which is difficult to form a firmly bonded film, for a long period of time, as well as organic materials such as fiber materials and textile products. The present invention relates to a coating agent for antibacterial and fungicide which exhibits an antibacterial and fungicidal effect and can form a transparent, thin and smooth film without impairing the surface condition of a substrate.

[0002]

2. Description of the Related Art Conventional antibacterial and antifungal coating agents include:
In some cases, an inorganic antibacterial agent (eg, apatite carrying silver) or an organic antibacterial agent (chlorhexidine) is dispersed or dissolved in a resin liquid containing an organic resin as a binder. Further, an antibacterial and antifungal coating agent in which silver-bearing apatite is dispersed in an alcohol solution of a metal alkoxide is mainly used for applications such as plastic and sand.

However, among the conventional antibacterial and antifungal coating agents, those using silver-bearing apatite have no sustained antibacterial and antifungal effect, and the coating is a heterogeneous dispersion system containing particles. In some cases, the surface properties of glass, plastic, and the like may be impaired. The antibacterial and antifungal coating agent in which an organic antibacterial agent is contained in the resin liquid has a drawback that high antibacterial properties are hardly exhibited because the antibacterial agent is hardly exposed on the resin surface.

[0004] A treatment liquid for forming an antibacterial and antifungal film that maintains an antibacterial and antifungal effect has been proposed in Japanese Patent Application Laid-Open No. Hei 7-165516. This processing solution contains a specific amount of metal alkoxide (eg, silicon tetraethoxide) in a solvent (eg, alcohol).
And chlorhexidine. As an optional component, an acid (crosslinking accelerator) such as hydrochloric acid or nitric acid and a thickener such as an acrylic resin or a vinyl acetate resin may be contained.

[0005] Although this treatment liquid is excellent in the persistence of the antibacterial and fungicidal effect, the treatment liquid is easily gelled immediately. And the surface properties of the substrate also deteriorate significantly. Therefore, there is an economical problem that much of the prepared processing solution is wasted, and it has been difficult to put it to practical use.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a surface condition of a substrate, such as metal, glass, and plastic, which is suitable for imparting antibacterial and antifungal properties to a smooth substrate having a relatively weak surface bond. It is an object of the present invention to provide an antibacterial and antifungal coating agent capable of forming an antibacterial and antifungal film which is extremely thin and transparent, has high hardness and adhesion, and maintains its effect.

[0007]

The coating agent for antibacterial and fungicide of the present invention comprises a hydrolyzable organic silane compound in an organic solvent and an acid catalyst selected from hydrochloric acid and nitric acid in an amount satisfying the following formula (1). In a silica sol solution having a viscosity of 10 cps or less and a silica sol concentration of 0.5 to 2.5% by weight in terms of SiO ₂ prepared by hydrolysis and condensation in the presence of an amount of water satisfying the following formula (2), the antibacterial agent and A coating agent for antibacterial and fungicide comprising a solution in which at least one organic agent selected from fungicides is dissolved at a concentration of 0.05 to 1% by weight.

0.004 ≦ [H] / [Si] ≦ 0.100 (1) 1.2 ≦ [H ₂ O] / [Si] ≦ 10.0 (2) where [H], [Si], and [H ₂ O] are respectively , Acid catalyst, hydrolyzable organic silane compound, and water. In the present invention, "viscosity" means the viscosity at room temperature (about 25 ° C).

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The hydrolyzable organic silane compound used as a raw material for preparing a silica sol in the present invention is typically tetraethoxysilane (= ethylsilicate), tetrapropoxysilane, methyltriethoxysilane, Alkoxysilanes such as dimethyldimethoxysilane and phenyltriethoxysilane. However, other chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane and phenyltrichlorosilane; tert-butyldimethylchlorosilane, N, N-bis
(Trimethylsilyl) urea, N, O-bis (trimethylsilyl) acetamide, hexamethyldisilazane, γ-
Chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxymethyldiethoxysilane, γ
-Methacryloxypropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-
β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, vinyltrichlorosilane And alkoxysilanes having a functional group such as vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, and vinyltrimethoxysilane.

Also, partial hydrolyzates of these organic silane compounds, for example, ethoxypolysiloxane partially hydrolyzed tetraethoxysilane, methoxypolysiloxane partially hydrolyzed methyldimethoxysilane, etc.
It can be used as a raw material for synthesis of silica sol.

The organic solvent used for the hydrolysis / condensation reaction of the organic silane compound includes alcohols such as methanol, ethanol, isopropanol, butanol and hexanol; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone and 4-hydroxy-4. Ketones such as -methyl-2-pentanone;
Hydrocarbons such as toluene, xylene, hexane, and cyclohexane; amides such as N, N-dimethylformamide and N, N-dimethylacetamide; and sulfoxides such as dimethylsulfoxide.

Preferred solvents are alcohols and mixtures of alcohols with other organic solvents. The alcohol may contain a small amount of 2-alkoxyethanol or β-diketone. Thereby, the film strength is improved.

According to the present invention, a hydrolyzable organic silane compound is hydrolyzed and condensed in an organic solvent in the presence of an acid catalyst comprising hydrochloric acid and / or nitric acid and water to prepare a silica sol. The amount of acid catalyst and water used in [H] / [S
i] is 0.004 to 0.100, preferably 0.01 to 0.08,
The molar ratio of [H ₂ O] / [Si] is 1.2 to 10.0, preferably 2.0 to 1
Be within the range of 0.0. The amount of water represented by [H ₂ O] includes the amount of water contained in the acid catalyst. After the silica sol thus synthesized is adjusted to a concentration of 0.5 to 2.5% by weight in terms of SiO ₂ and a viscosity of 10 cps or less, an organic antibacterial agent and / or a fungicide is dissolved in the silica sol, whereby the antibacterial agent of the present invention is obtained. A fungicidal coating agent is obtained.

This coating agent can be used for a relatively long time without causing gelation, and therefore the coating agent can be used without waste. The coating formed by applying the coating agent to the substrate and then curing by heating is smooth in surface and low in reflectivity, so that the surface state of the substrate can be seen as it is, that is, the surface state is not impaired.
Since this film has high hardness and adhesion, an antibacterial agent and / or a fungicide can be retained in the film for a long period of time, and the antibacterial and fungicidal effect is maintained.

As a catalyst, acids other than hydrochloric acid and nitric acid (for example,
When an organic acid such as phosphoric acid, sulfuric acid, or acetic acid is used, the hardness and adhesion of the film formed after heating are reduced, and the durability of the antibacterial and antifungal effect is reduced.

[0016] Even if the acid catalyst is hydrochloric acid and / or nitric acid, if the amount of the acid catalyst and water used exceeds the above range, gelation is likely to occur, making it difficult to use a coating agent and forming a formed film. Is deteriorated, and it becomes difficult to apply a thin film. If the amount of the acid catalyst or water is less than the above range, the hardness and adhesion of the film decrease, and the durability of the antibacterial and antifungal effect decreases.

The hydrolysis / condensation of the organic silane compound can be carried out at room temperature or under heating.
It is in the range of 20-80 ° C. The reaction is continued until the silane compound is completely hydrolyzed and a silica sol is formed. The formation of the silica sol can be determined by a change in viscosity or an analytical means such as GCP Mass. The obtained silica sol solution is diluted with a solvent if necessary (water can be used as the solvent at this time), and the silica sol concentration is reduced to 0.5 to 2.5% by weight, preferably 0.8 to 1.5% by weight in terms of SiO _2. The solution viscosity after the adjustment and the concentration adjustment is adjusted to 10 cps or less, preferably 5 cps or less.

The concentration of the silica sol solution is 0.1 in terms of SiO ₂ .
If the content is less than 5% by weight, the strength of the film is reduced, and the durability of the antibacterial and antifungal effect is reduced. If the concentration exceeds 2.5% by weight or the viscosity of the silica sol solution exceeds 10 cps, the accuracy of film formation decreases, and it becomes difficult to form a thin film.

At least one organic antibacterial agent and / or fungicide is added to the silica sol solution thus prepared and dissolved. The kind of the organic antibacterial agent and the fungicide to be used is not particularly limited, and an appropriate one may be selected according to the use and the use environment.

As the antibacterial agent, chlorhexidine represented by the following formula (a) and its trifluoromethyl derivative and salts thereof are preferable because of their high antibacterial effect, but benzalkonium chloride and the like can also be used. Preferred fungicides include thiabendazole (TBZ) and o-phenylphenol represented by the following formulas (b) and (c), respectively. In addition, propargyl-N.3
-Chlorophenyl carbamate can also be used.

[0021]

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Since chlorhexidine alone does not have a sufficient fungicidal effect, it is preferable to dissolve it in a silica sol solution together with a fungicide. The concentration of the antibacterial agent and / or fungicide in the silica sol solution (the total concentration when two or more agents are used) is in the range of 0.05 to 1% by weight, preferably 0.1 to 0.5% by weight. When the drug concentration is less than 0.05% by weight, the antibacterial property and / or the fungicide property are insufficient. If the drug concentration exceeds 1% by weight, the film forming properties of the coating agent of the present invention will be inhibited.

The antimicrobial and antifungal coating agent of the present invention can be applied to the substrate by various coating methods such as a spray method, a dipping method, a roll coating method, and a spin coating method. After coating, the film is formed even if left as it is, but it is preferably heated to 50 to 150 ° C. for about 10 minutes to 2 hours to make the film stronger. The dry thickness of the film is not particularly limited, but is usually 0.05 to 0.5 μm, preferably 0.08 to 0.15
A very thin film having a thickness of μm and having sufficient durability and, therefore, a long-lasting antibacterial and antifungal effect can be obtained.

Substrates to which the coating agent of the present invention can impart antibacterial and fungicidal properties are very diverse, from wood, natural and synthetic fibers and their products, organic materials such as plastics, to glass, metals, tiles, cement, concrete, and the like.
It can be applied to any of inorganic materials such as ceramics. Since the coating agent of the present invention can form a thin and uniform film having excellent transparency, low reflectivity and surface smoothness, it is particularly suitable for use in imparting antibacterial and fungicidal properties to products whose appearance is important. . Examples of such products include glassware, home appliances, films and the like.

[0025]

The present invention will be further described with reference to the following examples.
In Examples,% is% by weight unless otherwise specified.

Example 1 A reaction flask equipped with a cooler, a stirrer and a temperature controller was charged with a solvent ethanol,
Considering the amount of tetraethoxysilane in an amount of 10% in terms of SiO _{2 with} respect to this solvent, the amount of concentrated nitric acid in which the [H] / [Si] molar ratio is 0.01, and the amount of water contained in the concentrated nitric acid. Ion-exchanged water was added in such an amount that the molar ratio of ₂ O] / [Si] became 8, and reacted at 60 ° C. for 1 hour with stirring at 200 rpm to synthesize a silica sol solution. This solution was diluted 20 times with ethanol to prepare a silica sol solution having a silica sol concentration in terms of SiO ₂ of 0.5% and a viscosity of 1.8 cps.

Chlorhexidine (used as gluconate) 0.05% in this silica sol solution and thiabendazole
0.05% was dissolved to prepare a coating agent for antibacterial and fungicide. About three hours after the preparation of the coating agent, it was used for the following coating test in order to make the use conditions uniform.

The above coating agent was applied to glass by a dipping method and heated at 100 ° C. for 1 hour to obtain a dried film. Table 1 shows the results of examining the pencil hardness and the haze (measured with a haze meter) of this film (film thickness: 0.1 μm).

Separately, the above coating agent was applied to a polyethylene terephthalate film by a dipping method, and heated in the same manner as described above to form an antibacterial and antifungal film. This film was immersed in tap water for 2 weeks. The antibacterial and fungicidal properties of the films before and after immersion in tap water were investigated as follows. The results are also shown in Table 1.

An antibacterial film (2 × 2 cm) is placed in a sterilized container, and a bacterial suspension is prepared.
[Test strain: Staphylococcus aureus]
0.1 mL (the number of bacteria: about 5.0 × 10 ⁵ cells / mL) was inoculated, and the mixture was incubated at 35 ° C. for 18 hours in a thermostat. 10 m sterile water in container
The cells were collected by adding L and shaking, and the number of viable cells was counted.

A fungicidal film (3 × 3 cm) was placed on a potato dextrose agar medium, and a mold spore solution [mold: Tricoderm (Tricoderm) was prepared.
a)] About 0.1 mL (the number of spores: about 2.0 × 10 ⁶ / mL) was inoculated, cultured at 27 ° C. for 2 weeks in a thermostat, and the growth state of the mold after 2 weeks was observed.

Example 2 Example 1 was repeated except that the synthesis conditions of the silica sol solution and the concentrations of chlorhexidine and thiabendazole were changed as shown in Table 1. The test results are also shown in Table 1.

Example 3 Using hydrochloric acid as an acid catalyst,
Example 1 was repeated except that o-phenylphenol was used as a fungicide and the synthesis conditions of the silica sol solution were changed as shown in Table 1. The test results are also shown in Table 1.

(Comparative Examples 1-2) Example 1 was repeated except that the amounts of the acid catalyst and water used during the synthesis of the silica sol were changed as shown in Table 1. The test results are also shown in Table 1.

(Comparative Examples 3 and 4) Example 1 was repeated except that the dilution ratio of the silica sol solution was changed as shown in Table 1. The test results are also shown in Table 1.

Comparative Example 5 Example 3 was repeated except that the amounts of the acid catalyst and water used during the synthesis of the silica sol were changed as shown in Table 1.
Was repeated. The test results are also shown in Table 1. The viscosity of the silica sol solution after dilution was 10 cps or less in all cases except Comparative Example 4.

[0037]

[Table 1]

As shown in Table 1, the coating agent for antibacterial and fungicide of the present invention has a high film hardness, a low haze, forms a strong and transparent film, and is immersed in tap water for 2 weeks. After that, both the antibacterial effect and the fungicidal effect continued.

On the other hand, in Comparative Examples in which the synthesis conditions or the concentration of the silica sol were out of the range of the present invention, the film hardness was very low and the haze was high. Since the film was soft, both the antibacterial effect and the antifungal effect were significantly reduced after immersion in tap water for 2 weeks.

[0040]

As described above, the antibacterial and antifungal coating agent of the present invention can form an antibacterial and antifungal film having a thin and smooth surface and excellent transparency. Since this film has high hardness and high strength, the antibacterial and antifungal effect is maintained. Therefore, an antibacterial and antifungal property can be imparted to a substrate having a particularly beautiful surface for a long period of time without impairing the surface condition of the substrate, and the application range of the antibacterial agent and the antifungal agent can be expanded.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Akira Nishihara 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Mitsubishi Materials Corporation Research Laboratory

Claims (3)

[Claims] In an organic solvent, a hydrolyzable organosilane compound is hydrolyzed in the presence of an acid catalyst selected from hydrochloric acid and nitric acid in an amount satisfying the following formula (1) and water in an amount satisfying the following formula (2). In a silica sol solution prepared by decomposition and condensation and having a viscosity of 10 cps or less and a silica sol concentration of 0.5 to 2.5% by weight in terms of SiO ₂ , at least one selected from an antibacterial agent and a fungicide is added.
An antibacterial and antifungal coating agent comprising a solution in which various organic agents are dissolved at a concentration of 0.05 to 1% by weight. 0.004 ≦ [H] / [Si ] ≦ 0.100 (1) 1.2 ≦ [H 2 O] / [Si] ≦ 10.0 (2) However, [H], [Si] , [H 2 O] , respectively, an acid catalyst , The hydrolyzable organic silane compound and the molar amount of water. 2. The antifungal coating agent according to claim 1, comprising a solution in which at least one antimicrobial agent containing chlorhexidine and at least one antifungal agent are dissolved in the silica sol solution. 3. An antibacterial and antifungal film having a dry film thickness of 0.05 to 0.5 μm, formed on the substrate from the coating agent according to claim 1 or 2.