JPH08311373A - Photocurable composition for antibacterial coating - Google Patents

Abstract

(57) [Summary] [Structure] (A) 100 parts by weight of an acrylate-based polymerizable monomer containing 10% by weight or more of a polyfunctional acrylate-based polymerizable monomer such as tetraethylene glycol diacrylate, B) A photocurable antibacterial film containing 0.001 to 0.5 part by weight (as silver equivalent) of a silver salt such as silver nitrate, and (C) 0.1 to 5 parts by weight of a photopolymerization initiator. Composition. [Effects] The photocurable composition for antibacterial coating of the present invention can easily form an antibacterial coating by coating it on a substrate and then irradiating it with light, particularly ultraviolet light. Further, the coating film thus obtained exhibits not only high antibacterial properties but also excellent properties such as film strength, adhesiveness, transparency and slidability. Further, since silver ions are generally unstable to light, moisture, acid, alkali, etc., there is a problem in storage stability of the photocurable composition for antibacterial coating,
By setting the content of water in the composition to 1000 ppm or less, the above-mentioned problem of storage stability can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable composition for an antibacterial film, which comprises a photocurable acrylate-based polymerizable monomer containing a silver salt as an antibacterial agent.

[0002]

2. Description of the Related Art In recent years, products having antibacterial properties and antifungal properties have attracted attention. Among them, resin molded products and films to which an antibacterial agent containing silver ions as an active ingredient is added are excellent in antibacterial performance and safety, and have already been put into practical use.

For example, Japanese Patent Application Laid-Open No. 63-265958 discloses an antibacterial resin composition containing an antibacterial zeolite containing silver, copper and zinc ions. In the case of a resin product in which such antibacterial powder is kneaded, the antibacterial powder is expensive, so the cost is high when making a large molded product, and the resin is colored or the antibacterial property is insufficient. There was a problem of doing.

On the other hand, a method of forming an antibacterial film or coating on the surface of a resin molded product or the like is also known. The method of forming an antibacterial film or coating film is more cost effective than the resin product in which the antibacterial powder is kneaded,
Moreover, since the coatings and coatings are generally thin, it is expected that there will be few coloring problems. For example, JP-A-60-202
No. 162 discloses an antiseptic and antifungal coating composition containing antibacterial zeolite solid particles containing silver, copper and zinc ions. JP-A-5-117585
The publication discloses a polyurethane antibacterial resin coating material containing organic acid copper or organic acid silver. Japanese Unexamined Patent Publication No. 6-107972 discloses an antibacterial coating composition obtained by mixing an ultraviolet curable coating with an antibacterial and antifungal inorganic gel and fine particles having a large surface area containing silver ions. JP-A-6-264008 discloses a coating solution composition for forming an algae-proof transparent coating film, which comprises a hydrolyzate of an alkoxysilane and a silver salt having antibacterial properties. In addition, we have already proposed an antibacterial coating composition and an antibacterial coating composition using an antibacterial agent composed of a specific silver complex.

[0005]

The method of forming these antibacterial coatings and coatings has the advantage that the amount of expensive antibacterial agent can be reduced because the antibacterial agent is not kneaded into the inside of the resin molded product. However, the following problems remain.

In the antibacterial coating or coating composition using an antibacterial agent composed of inorganic powder such as antibacterial zeolite solid particles or fine particles having a large surface area containing silver ions in an inorganic gel, the agglomeration of the inorganic powder or the prepared coating or coating is used. There are problems with the smoothness and transparency of the membrane. Polyurethane-based antibacterial resin coatings and alkoxysilane-based algae-proof transparent coating film-forming coating liquid compositions require heating to cure the film, and thus have the problem of poor productivity industrially. be pointed out.

Further, silver ions are generally unstable to light, especially ultraviolet rays, moisture, acids, alkalis, etc., so that there is a problem in storage stability of the photocurable composition for antibacterial coating. In the coating composition containing the antibacterial agent, silver ions are oxidized or reduced with the passage of time to form silver or silver oxide colloids, and the composition is often colored. The photocurable composition for antibacterial coatings produced by such colloid of silver or silver oxide has low antibacterial performance even if a uniform coating can be formed, and in some cases, the composition causes phase separation. In some cases, a uniform coating cannot be formed.

[0008]

Means for Solving the Problems As a result of intensive studies aimed at solving the above problems, the present inventors have found that by using a silver salt as an antibacterial agent containing an acrylate-based polymerizable monomer as a main component, The inventors have found a photocurable composition for an antibacterial film, which has excellent selectivity and transparency and storage stability, and completed the present invention.

That is, according to the present invention, (B) silver is added to 100 parts by weight of a resin component comprising (A) an acrylate-based polymerizable monomer containing 10% by weight or more of a polyfunctional acrylate-based polymerizable monomer. A photocurable composition for an antibacterial film, which comprises 0.001 to 0.5 part by weight of a salt (as silver equivalent) and 0.1 to 5 parts by weight of (C) a photopolymerization initiator.

The silver salt used in the present invention is not particularly limited as long as it is a silver salt capable of releasing silver ions. In particular,
Examples thereof include silver salts such as silver nitrate, silver acetate and silver perchlorate. Although these silver salts are solids themselves, they can be used as a liquid by dissolving them in a solvent such as alcohols such as ethanol and isopropanol, ethers such as diethyl ether, and ketones such as acetone.

Further, a known silver complex can be used as a silver salt. The silver complex is characterized in that it is a liquid itself or is easily dissolved in a solvent such as alcohol. The silver complex generally exists in the form of a salt in which a ligand having a metal coordination group coordinates with silver.

Preferred representative examples of the metal coordinating group in the ligand include H ₂ N-, CH ₃ N (H)-, 2-pyridyl group and 2-
Pyrrolyl group, 2-quinolyl group, imidazoyl group, HS
-, CH ₃ S-, 2-thienyl group, HOOC-, etc. monodentate ligands; H ₂ N (CH ₂ ) ₂ NH-, H ₂ N (CH ₂ ) ₃ NH
-, 4- (2,2'-bipyridyl) group, 5- (1,10
-Phenanthrolyl) group, HS (CH ₂ ) ₂ S-, 5 (8
-Hydroxyquinolyl) group etc. capable of bidentate coordination; H
_{2 N (CH 2) 2 NH} (CH 2) may exhibit a tridentate possible ones, etc. ₂ NH- or the like.

Of these, considering handling operability and the like,
_{H 2 N-, H 2 N (} CH 2) NH-, H 2 N (CH 2) 2 NH
(CH _{2) 2} NH-, pyridyl, 2-quinolyl group, imidazolyl group, and the like are particularly preferred.

Specific examples of the compound (ligand) having the above metal coordination group in the molecule include pyridine, 2-vinylpyridine, 4-vinylpyridine, 2-pyridylmethanol, 2-pyridinecarboxylic acid, imidazole, 1- Vinylimidazole, 4,5-imidazoledicarboxylic acid, quinoline, 2-vinylquinoline, 6-quinolinecarboxylic acid, quinoxaline, allylamine, ethylenediamine, N, N-diethylethylenediamine, para-phenylenediamine, 2,2'-bipyridine, diethylenetriamine, allylurea, Examples thereof include acrylamide, dimethylaminoethyl methacrylate and methacrylic acid amide.

By the way, the above ligand may have a polymerizable unsaturated group in the molecule together with the above metal coordination group.
Specific examples of the polymerizable unsaturated group include vinyl group, allyl group, acryl group and methacryl group.

Specific examples of typical ligands having a polymerizable unsaturated group in the molecule together with a metal coordinating group include 2-vinylpyridine (hereinafter referred to as 2VPY) and 4-vinylpyridine (hereinafter referred to as 4VPY). , 1-vinylimidazole (hereinafter referred to as 1VIMD), 2-vinylquinoline,
Allylamine (hereinafter referred to as ALA), allylurea, acrylamide, dimethylaminoethyl methacrylate,
Methacrylic acid amide and the like.

The silver (salt) coordinated by the ligand is as follows:
Examples thereof include silver salts such as silver nitrate, silver acetate, and silver perchlorate.

A specific example of a silver complex is [Ag (2
VPY) ₂ ] NO ₃ , [Ag (4VPY) ₂ ] NO ₃ , [A
g (1VIMD) ₂ ] NO ₃ , [Ag (ALA) ₂ ] NO ₃
Silver complexes such as

As described above, since the silver complex has a polymerizable unsaturated group, it is copolymerized with the acrylate-based polymerizable monomer which is the main component in the antibacterial coating, so that the silver complex is chemically contained in the coating. Once fixed, the coating exhibits a long-lasting antibacterial property. In addition, since the compatibility of the silver complex with the coating component containing the acrylate-based polymerizable monomer as a main component is high, the silver complex is uniformly dispersed in the antibacterial coating on a molecular order, so that the concentration of the silver complex is It has the characteristics that it is difficult to discolor even when it is high and has excellent weather resistance.

The acrylate-based polymerizable monomer used in the present invention includes (meth) acrylic acid and methyl (meth)
Acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate,
Butoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, ethylene glycol mono (meth) acrylate, methyltriglycol (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, glycidyl methacrylate, cyanoethyl acrylate ,
Examples thereof include acrylate or methacrylate polymerizable monomers such as dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and methacryloxyethyl phosphate. The polyfunctional acrylate-based polymerizable monomer used in the present invention refers to a polymerizable monomer having two or more polymerizable unsaturated groups such as an acrylic group and a methacrylic group, and specifically, ethylene glycol diester. (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2, bis (4-acryloxypolyethoxyphenyl) propane, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol Diacrylate, polyethylene glycol # 400 Di (meth) acrylate, polyethylene glycol # 60
Bifunctional acrylate-based polymerizable monomers such as di (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerol triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, triary Trifunctional or higher functional acrylates or methacrylates such as di (meth) acrylate, tri (meth) acrylate, tetra (meth) acrylate, penta (meth) acrylate, hexa (meth) acrylate, etc. such as lucyanurate, triallyl isocyanurate, etc. A polymerizable monomer may be used.

In the photocurable composition for antibacterial coating of the present invention, the acrylate-based polymerizable monomer containing 10% by weight or more of the above-mentioned polyfunctional acrylate-based polymerizable monomer may be used as a resin component. Required. More preferably, the amount of the polyfunctional acrylate-based polymerizable monomer is 30% by weight or more. When the content of the polyfunctional acrylate-based polymerizable monomer is less than 10% by weight, the cross-linking density of the film is insufficient, resulting in poor polymerization and insufficient film strength.

In addition to the above-mentioned monomers, the resin component may contain an acrylic polymer or oligomer such as polyester acrylate, epoxy acrylate, urethane acrylate, and silicon acrylate. These polymers and oligomers may be added for the purpose of adjusting the viscosity of the composition, increasing the degree of polymerization, or improving the adhesion to the substrate. The ratio of the polymer or oligomer in the resin component is in the range of 0 to 50% by weight.

Examples of the photopolymerization initiator used in the present invention include 2,2-diethoxyacetophenone, benzyldimethylketal, benzophenone, methyl o-benzoylbenzoate, bis (4-dimethylaminophenyl) ketone, 1,2-diphenyl. Ethanedione, 2-phenyl-2-hydroxy-acetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 4 '
-Isopropyl-2-hydroxy-2-methyl-propiophenone, 2-hydroxy-2-methyl-propiophenone, thioxanthone, 2-methylthioxanthone,
Illustrative examples include those that generate radicals by irradiating light in the near ultraviolet region (300 to 450 nm) such as 1-hydroxycyclohexyl phenyl ketone. Besides this,
As a photosensitizing aid, tertiary amines such as N, N-dimethyl-p-toluidine, tributylamine, N-methyldiethanolamine, p-dimethylaminobenzoic acid ethyl ester, anthraquinone, 5-nitrofluorene, 5 -Nitroacenaphthene and the like can be used together.

The mixing ratio of each constituent of the present invention is (A)
Resin component 1 comprising an acrylate-based polymerizable monomer containing 10% by weight or more of the polyfunctional acrylate-based polymerizable monomer
The silver salt of (B) is added in an amount of 0.001 to 0.
5 parts by weight (as silver equivalent), 0.1 to 5 parts by weight of the photopolymerization initiator (C).

The blending ratio of the silver salt (B) is not particularly limited as long as it is within the range of exhibiting antibacterial properties, and can be appropriately determined in consideration of economic efficiency and pollution to the environment. it can. However, the higher the concentration of silver ions in the antibacterial coating, the higher the antibacterial performance, but there is a tendency that the antibacterial coating is easily colored. Further, in consideration of economical efficiency and environmental consideration, it is better to keep the concentration of silver ions as low as possible. Therefore, the blending ratio of the silver salt of (B) is in the range of 0.001 to 0.5 parts by weight, preferably 0.0 by weight in terms of silver, relative to 100 parts by weight of (A).
05-0.1 parts by weight, more preferably 0.01-0.
A range of 05 parts by weight is particularly preferred. In addition to silver ions, copper ions, zinc ions, and the like are known as metal ions having antibacterial properties. There is no problem with using such a metal salt that releases an antibacterial metal ion other than silver ion.

The mixing ratio of the photopolymerization initiator (C) is 0.
It is preferably in the range of 1 to 5 parts by weight. If it exceeds 5 parts by weight, the coating may turn yellow. If the amount is less than 0.1 part by weight, the coating may be insufficiently cured.

In addition to the above-mentioned essential components, the photocurable composition for antibacterial coatings of the present invention also contains various kinds of compounds conventionally added to photocurable compositions for coatings, paints and the like. The additives for paints can be blended in conventional amounts, and specifically, coloring pigments, dyes, leveling agents, defoaming agents, slip agents and the like can be added.

The photocurable composition for antibacterial coating of the present invention may be used as it is or may be diluted with a solvent before use. Generally, when forming a film, it is easier to form a thin uniform film because the viscosity can be lowered by diluting with a solvent. As the solvent, alcohols such as methanol, ethanol and isopropanol, ethers such as diethyl ether, ketones such as acetone and esters such as ethyl acetate are used.

The acrylate-based photocurable composition for coating, which comprises the polyfunctional acrylate-based polymerizable monomer (A) and the photopolymerization initiator (C) as basic components, is cured by irradiation with ultraviolet rays. Generally, it is commercially available as a hard coating agent, ink, paint, etc. Specific examples of product names include Sanuscoat US-40H (manufactured by Sun Arrow Chemicals), Fujihard HO9257U (manufactured by Fujikura Kasei), Unidick 17-806 (manufactured by Dainippon Ink and Chemicals), Seika Beam PHC X-8 (large). Nissei Kagaku Co., Ltd.) and the like.

By the way, silver ions are not always stable to light such as ultraviolet rays, moisture, acids and alkalis, oxidizing agents and reducing agents, and temperature history. Therefore, there is a problem in the storage stability of the curable composition for a coating film after adding the silver salt.

In the photocurable composition for antibacterial coating of the present invention, it was found that the storage stability of the composition is greatly influenced by the content of water. That is, in the photocurable composition for antibacterial film of the present invention, the water content is 10%.
It is desirable that the content is 00 ppm or less. When the content of water in the composition exceeds 1000 ppm, silver ions are oxidized or reduced with the lapse of time, colloid of silver or silver oxide is formed, and the composition is colored or a uniform film is formed. May not be formed. In addition, the coating film produced using such a composition has a reduced antibacterial performance,
It may be colored.

Since such storage stability is proportional to the content of water in the photocurable composition for antibacterial coating, the lower the content of water, the better. Therefore, it is desirable that the water content is 1000 ppm or less, preferably 500 ppm or less, and more preferably 300 ppm or less.

In order to control the water content, each component constituting the photocurable composition for antibacterial film is purified by distillation, column or the like, or molecular sieves, anhydrous magnesium sulfate, anhydrous sodium sulfate are used. And a dehydrating agent. Further, the content of water in the composition can be measured by using a Karl Fischer moisture meter or the like.

As described above, in the photocurable composition for antibacterial coating of the present invention, the storage stability of the composition is greatly affected by the content of water in the composition. The storage stability may also be affected by the pH of the. Since the stability of silver ions is low in strong acidity and alkalinity, the pH of the photocurable composition for antibacterial coating is 4
The range of to 7 is desirable. If the amount is out of the above range, colloidal silver oxide or silver is likely to be deposited because the oxidation or reduction of the silver salt is likely to proceed, resulting in loss of uniformity of the photocurable composition for the antibacterial coating or the composition. The antibacterial property of the antibacterial coating using the object may be reduced. Therefore, in the photocurable composition for antibacterial film of the present invention, the storage stability is further improved by setting the content of water in the composition to 1000 ppm or less and adjusting the pH of the composition to the range of 4 to 7. Can be increased. In order to adjust the pH within the above range, the purified raw materials are used for the respective components constituting the photocurable composition for antibacterial coating, and the pH is adjusted with an acid such as carboxylic acid or an alkali such as amine. The method of adjusting is mentioned. The pH of the composition is a pH meter or a pH.
It can be measured with a test strip.

As described above, in the photocurable composition for antibacterial film of the present invention, the storage stability can be improved by controlling the content of water.
The performance of the antibacterial coating can be further improved by separately packaging the silver salt as the antibacterial agent and the other components of the photocurable composition for the antibacterial coating and mixing the two immediately before use. In particular, in spray coating and the like, a solution containing a silver salt and a liquid containing a curable composition for a film are separately led to just before the spray nozzle, and each is adjusted so as to be mixed at a constant ratio. The method of spraying is also suitably used.

The photocurable composition for antibacterial coating of the present invention comprises
As it is or after adjusting the viscosity with a solvent, the target substrate is coated by spray coating, dip coating, roller coating, brush coating, spin coating or the like, and an antibacterial coating is formed by photocuring with ultraviolet rays or the like. The thickness of the antibacterial coating formed may be thick, but in consideration of economy and the like, it is 0.1 to 100 μm, preferably 0.5 to
A range of 50 μm, more preferably 1 to 20 μm is suitable.

The photocurable composition for antibacterial coating of the present invention comprises
It can be used in various fields requiring antibacterial properties and antifungal properties, and the object and application for forming the film are not limited. Specific objects include plastic, paper,
Examples include cloth, metal, wood, glass, ceramics, cement and the like. Examples of applications include paints for interior and exterior of hospitals, schools, general houses, food factories, warehouses, etc., paintings mainly for the purpose of preventing mold on walls, ceilings, floors of bathrooms, toilets or kitchens, and antibacterial fungicidal properties. Examples include plastic products to which is added, wood products such as furniture, beverage cans, metal products such as pipes, etc.

Although many plastic products, wooden products, metal products and the like may be painted for the purpose of coloring or protective coating, the antibacterial coating of the present invention is formed by forming the coating on the outermost surface of the final product. The most effective antibacterial effect can be obtained. In addition, for the purpose of improving the surface hardness of plastic and protecting coating of wood, etc.
A film may be formed on the outermost surface of the product. In such a case, a new function of antibacterial property can be obtained by using the photocurable composition for an antibacterial film of the present invention. Can be added. That is, it can be said that the antibacterial coating of the present invention is a technique of adding a new function of antibacterial property without deteriorating the original purpose of the conventionally known curable composition for coating.

The antibacterial property of the photocurable composition for antibacterial film of the present invention can be evaluated by a known method. For example, the bacterial count method and shake flask method, which are the antibacterial and deodorant processing evaluation test methods of the Textile Products Hygiene Council, the bacterial growth inhibition test method of antibacterial fiber products of the Japan Society for Antibacterial and Antifungal, American AATCC Test Method's Agar Plate Method and evaluation method for antibacterial processing of textiles, JIS mold resistance test method (JIS Z
2911), antifungal efficacy test methods and the like.

[0040]

INDUSTRIAL APPLICABILITY The photocurable composition for antibacterial coating of the present invention can easily form an antibacterial coating by coating it on a substrate and then irradiating it with light, especially ultraviolet rays. Furthermore, the film thus obtained not only exhibits high antibacterial properties, but also has film strength, adhesion, transparency,
It also has excellent properties such as lubricity.

Since silver ions are generally unstable to light, especially ultraviolet rays, moisture, acids, alkalis, etc., the silver ions in the photocurable composition for antibacterial coatings are oxidized or reduced over time. In some cases, colloid of silver or silver oxide is generated, and the composition may be colored or the antibacterial performance of the antibacterial coating may be deteriorated. In the photocurable composition for antibacterial coatings of the present invention, the problem of storage stability can be improved by further setting the content of water in the composition to 1000 ppm or less.

[0042]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples.

1. Sample Preparation About 50 × 50 m of the photocurable composition for antibacterial coating of the present invention
It coated on the acrylic plate of m using a bar coater. A sample having an antibacterial coating formed thereon was prepared by irradiating the coating film with ultraviolet rays for 2 minutes using an ultraviolet irradiation device using a xenon lamp as a light source. In addition, a coating film to which no antibacterial agent was added was also prepared in the same manner and used as a comparative sample. The film thickness was measured using a surface roughness meter.

2. Antibacterial test A culture solution of a test bacterium, which was shake-cultured in a normal broth medium at 35 ° C. for 16 hours, was diluted 20000 times with a phosphate buffer solution to obtain a test bacterium solution. Escherichia coli was used as the bacterial species unless otherwise specified. Next, on the surface of the sample placed in the petri dish, 1 ml of the above-mentioned bacterial solution was made into about 50 droplets and dropped at regular intervals. The dish was covered and stored at 25 ° C. for 24 hours.
The sample after storage was taken out, washed out with 9 ml of liquid medium, and the number of viable bacteria in the washed out solution was measured by the pour plate culture method using an agar medium. The viable cell count was converted per sample.

3. Evaluation of Transparency The transmittance (wavelength 589 nm) of the coating film or coating film of the present invention was measured using a spectrophotometer to evaluate the transparency.

4. Measurement of Water Content The water content of the photocurable composition for antibacterial coating is measured by a digital trace water content measuring device (CA-02 manufactured by Mitsubishi Kasei Kogyo Co., Ltd.).
Type). However, since silver ions interfere with the measurement in the above apparatus, the measurement was performed using the photocurable composition for a coating film before adding the silver salt.

5. Measurement of pH The pH of the photocurable composition for antibacterial film was measured using a pH meter (M-12 model, manufactured by Horiba Ltd.).

Examples 1 to 4 First, a silver complex was synthesized as follows.

In a dry box, 17 g of silver nitrate was added to 2-
When 21 g of vinylpyridine (hereinafter abbreviated as 2VPY) was added and stirred for 3 hours, a viscous and uniform pale yellow solution was obtained. As a result of the analysis, in the obtained compound, nitrogen in the pyridine ring was coordinated to silver ion, and [Ag (2VPY) ₂ ]
It was found to be a silver complex having the chemical structure of NO ₃ .

Then, a photocurable composition for antibacterial coating was prepared as follows. A photocurable composition for coating film having the composition shown in Table 1 was prepared, and further as a photopolymerization initiator,
3% by weight of 1-hydroxycyclohexyl phenyl ketone was added. It was diluted with isopropanol as a solvent so that the solid content concentration was 40%. Next, [Ag (2VPY) ₂ ] NO ₃ was added so that the silver concentration would be 300 ppm with respect to the total solid content of the curable composition for coating, to prepare a photocurable composition for antimicrobial coating. did. Unless otherwise specified, each component constituting the photocurable composition for antibacterial film used in the following examples was dehydrated in advance.

[0051]

[Table 1]

The water content of the photocurable composition for antibacterial coating was measured and found to be 80 ppm.

Next, a sample having an antibacterial coating formed thereon was prepared using the above photocurable composition for antibacterial coating. The film thickness at this time was about 4 μm. Table 2 shows the evaluation results of the antibacterial coating.

From the above results, all the coatings showed high transparency and antibacterial property. It was also found that all the coatings had a smooth surface condition and sufficient film strength was obtained.

Examples 5 and 6 A photocurable composition for an antibacterial coating was prepared in the same manner as in Example 1 except that the silver concentration based on the total solid content in the photocurable composition for an antibacterial coating was 50 ppm and 1000 ppm. Was prepared. Next, an antibacterial coating was prepared in the same manner as in Example 1, and the coating was evaluated. Table 2 shows the results. based on the above results,
It was found that when the silver concentration was in the range of 50 to 1000 ppm, high transparency and antibacterial properties were exhibited.

Example 7 A photocurable composition for an antibacterial film was prepared in the same manner as in Example 1 except that silver nitrate dissolved in isopropanol was used as the antibacterial agent. Next, an antibacterial coating was prepared in the same manner as in Example 1, and the coating was evaluated. Table 2 shows the results. From this result, it was found that a film having high transparency and antibacterial property can be obtained even when silver nitrate is used as the silver salt.

Comparative Examples 1 to 4 Films were prepared in the same manner as in Examples 1 to 4 without adding any silver salt. Table 2 shows the results. As described above, no antibacterial property was exhibited without containing silver salt.

Comparative Example 5 A photocurable composition for antibacterial coating was prepared in the same manner as in Example 1 except that the photocurable composition for coating shown in Table 1 was used, and the antibacterial coating was prepared using the composition. Was produced. As a result, the coating film had a polyfunctional acrylate-based polymerizable monomer content of 5%.
Since the content was as small as wt%, a coating having sufficient strength could not be obtained.

[0059]

[Table 2]

Examples 8 to 11 Photocurable compositions for antibacterial coatings were prepared in the same manner as in Examples 1 to 4. Each was sealed and stored in a cool and dark place, and observed for 3 months. Also, in the same manner as in Example 1, an antibacterial coating was prepared using each composition after 3 months, and the coating was evaluated. The results are shown in Table 3. As described above, in the composition having a water content of 1000 ppm or less, no change in the composition was observed for 3 months, and high antibacterial property was maintained even in the coating film prepared 3 months later.

Comparative Examples 6 to 9 The photocurable compositions for antibacterial coatings were prepared in the same manner as in Examples 1 to 4 without prior dehydration treatment when preparing the photocurable compositions for antibacterial coatings. Prepared. Each was sealed and stored in a cool and dark place, and observed for 3 months. Also, in the same manner as in Example 1, an antibacterial coating was prepared using each composition after 3 months, and the coating was evaluated. The results are shown in Table 3. When the dehydration treatment was not performed in this way, the storage stability was poor because the water content was high. In addition, the antibacterial property of the film produced after 3 months was also low.

[0062]

[Table 3]

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Claims (2)

[Claims] 1. A silver salt of 0.001 is added to 100 parts by weight of a resin component comprising (A) an acrylate-based polymerizable monomer containing 10% by weight or more of a polyfunctional acrylate-based polymerizable monomer. A photocurable composition for an antibacterial coating, which comprises 0.1 to 0.5 parts by weight (as silver equivalent) and 0.1 to 5 parts by weight of (C) a photopolymerization initiator. 2. The photocurable composition for an antibacterial film according to claim 1, wherein the water content is 1000 ppm or less.