Coating agent absorbing ultraviolet ray with function of antibacterial, antimold

Abstract

To provide longevity to wood, coatings and clear paints that absorb ultraviolet rays have been applied to preserve the beauty of the wood grain in unpainted wood and to extend its lifespan, but over many years, discoloration and fading of the wood occurred, and mold such as black mold and blue mold also developed on the wood, the present invention challenges to overcome the problem.SOLUTION: By incorporating trace amounts of antibacterial metals such as silver into coatings and clear paints that absorb ultraviolet rays, it has become possible to prevent mold growth on wood and to address issues of discoloration and fading in unfinished wood.SELECTED DRAWING: None

Description

[Technical Field]

[0001] In order to preserve the beauty of the grain of wood such as plain wood and to extend its lifespan, coating agents and clear paints that absorb ultraviolet rays have been applied, but these coatings cause discoloration and fading of the plain wood and also cause the growth of mold such as black mold and blue mold, making it difficult to extend the lifespan of wood.The present field of the invention is related to preserving the beauty of wood and extending the lifespan of wood. [Background technology]

[0002] Although coating agents and paints that absorb ultraviolet rays have existed until now, there have been no ultraviolet-absorbing coating agents or paints that maintain the beauty of plain wood for many years, prevent discoloration and fading of wood, prevent the growth of mold such as black mold and blue mold, and aim to extend the life of wood. The present invention relates to an ultraviolet-absorbing coating agent that maintains the beauty of wood for as long as possible against deterioration over time, has antibacterial and antifungal functions, and aims to extend the life of wood.

[0003] The following four patent applications have been filed so far relating to UV-absorbing coating agents and paints, but they relate to paint resins, and no prior patents have been found relating to UV-absorbing coating agents and paints intended to extend the life of wood. [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-035610 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-208544 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-208543 [Patent Document 4] Japanese Patent Application Laid-Open No. 2002-069137 [Patent Document 5] Japanese Patent Application Laid-Open No. 2002-069136 Summary of the Invention

[0004] The present invention relates to an ultraviolet absorbing coating agent and paint that can maintain the beauty of the grain of wood such as plain wood and extend its life. [Problem to be solved by the invention]

[0005] Until now, there have been coating agents and paints that can be applied to wood to absorb ultraviolet rays, but it has been difficult to maintain the beauty of plain wood for many years, and the plain wood can become discolored or faded, and mold such as black mold and blue mold can grow on the wood, making it difficult to maintain the beauty of plain wood for many years. [Means for solving the problem]

[0006] In this invention, organic absorbers are used as ultraviolet absorbers in coating agents and paints that absorb ultraviolet light in order to maintain the beauty of the grain of wood such as plain wood and to extend its lifespan. However, by using a zinc-based inorganic ultraviolet absorber in addition to this and further adding a small amount of antibacterial metal such as silver, it is possible to suppress the growth of mold on the wood and solve the problem of discoloration and fading of plain wood.

[0007] It has been found that the present invention not only makes it possible to maintain the beauty of the grain of wood such as plain wood, but also extends the life of the lumber, thereby contributing to the extension of the life of the wood.

[0008] The present invention relates to coating agents and clear paints that absorb ultraviolet light and are applied to wood, and can be broadly divided into water-soluble and solvent-based types.

[0009] Binder resins used in water-soluble coating agents and paints include acrylic emulsions, acrylic silicone emulsions, urethane emulsions, fluororesin emulsions, and covalent compounds that combine these resins. Acrylic silicone resin and fluororesin emulsions are highly weather-resistant and durable, making them suitable for long-term use.

[0009] The blending amount of binder resin used in water-soluble coating agents and paints is 10 to 90% by weight, and particularly preferably 30 to 80% by weight.

[0010] Binder resins used in solvent-based coating agents and paints include alkyd resins, acrylic silicone resins, fluororesins, and alkyl silicate resins. Among these, alkyl silicate resins are particularly excellent in weather resistance and durability because they form an inorganic glass film. They are particularly preferred for the ultraviolet-absorbing coating agent of the present invention because they allow the agent to maintain its function for many years.

[0011] The content of inorganic binders used in solvent-based coating agents and paints is 10 to 80% by weight, and particularly preferably 20 to 70% by weight.

[0012] The ultraviolet absorbers to be incorporated into the ultraviolet absorbing coating agent and paint of the present invention include organic compounds and inorganic compounds.

[0013] Organic compound UV absorbers include octyl methoxycinnamate, dimethyl PABA octyl, t-butyl methoxydibenzoylmethane, benzophenone, benzotriazole, triazine, etc. Any of these can be used as the UV absorber, but 2-hydroxy-4-methoxybenzophenone, a representative example of the benzophenone family, is preferred due to its high UV absorption performance.

[0014] The amount of the organic compound ultraviolet absorber to be blended is preferably 0.01 to 10% by weight, and more preferably 0.1 to 5% by weight.

[0015] Inorganic ultraviolet absorbers include zinc oxide, titanium oxide, etc. Furthermore, zinc oxide and zinc oxide doped with Ga, As, Ag, Cu, etc. are particularly preferred because they can enhance ultraviolet absorption.

[0016] The content of the inorganic compound ultraviolet absorber is 0.1 to 40% by weight, and 1 to 30% is particularly desirable.

[0017] In addition, in the present invention, in order to maintain the beauty of the wood for many years, improve the preservation properties of the wood, and suppress the growth of black mold and blue mold, it is desirable to add small amounts of metals such as silver, copper, and zinc, and compounds of these metals, as antibacterial and antifungal metals. The metal compounds that can be used include compounds obtained by reacting metals such as silver, copper, and zinc with acidic substances. Examples of such compounds include chlorides, sulfates, nitrates, and acetates.

[0018] The content of the antibacterial metal or antibacterial metal compound is preferably 0.001 to 1% by weight, and 0.1 to 0.5% is particularly desirable as the blending amount. [Example] Example 1

[0019] The ultraviolet absorbing coating agent is prepared by mixing the following raw materials in the following proportions. The mixed raw materials are mixed and dispersed in a Henseshell mixer to produce the ultraviolet absorbing coating agent. Raw material composition ratio 1. Acrylic emulsion 80% by weight 2. Benzotriazole 5% by weight 3) Zinc oxide 10% by weight 4. Copper chloride 5% by weight The UV absorbing coating agent formulated as described above was investigated for its UV absorbing performance and antibacterial properties. To measure UV absorbing performance, the coating was applied to a glass plate with a doctor blade to a thickness of approximately 10 μm, and after the coating had dried thoroughly, the coated glass plate was irradiated with a black light and the amount of UV light transmitted was measured with a Topcon Technohouse UV intensity meter (main body: UV R-300, light receiving part: UD-360A). The UV transmittance was compared with that of an uncoated glass plate, and the UV absorbance was calculated from the decrease in UV light transmission.

[0020] Antibacterial properties were evaluated according to JIS L 1902 using Escherichia coli and Staphylococcus aureus as test bacteria.

[0021] The antifungal properties were evaluated against Aspergillus niger based on JIS Z 2911.

[0022] The coating agent prepared in Example 1 had the following properties: TIFF2025183124000001.tif42156 Example 2

[0022] The raw materials used for the ultraviolet absorbing coating agent were prepared according to the blending ratios below, and then mixed and dispersed in a Henseschel mixer to obtain an ultraviolet absorbing coating agent in the same manner as in Example 1. The ultraviolet absorbing performance, antibacterial performance, and antifungal performance of the obtained coating agent were evaluated in the same manner as in Example 1.

[0023] Raw material composition ratio 1. Urethane emulsion 80% by weight 2. Benzotriazole 5% by weight 3) Zinc oxide 10% by weight ▲4▼ Copper nitrate 5% by weight

[0024] The coating agent prepared in Example 2 had the following properties: TIFF2025183124000002.tif42156 Example 3

[0025] The raw materials used for the ultraviolet absorbing coating agent were prepared according to the blending ratios below, and then mixed and dispersed in a Henseschel mixer to obtain an ultraviolet absorbing coating agent in the same manner as in Example 1. The ultraviolet absorbing performance, antibacterial performance, and antifungal performance of the obtained coating agent were evaluated in the same manner as in Example 1.

[0026] Raw material composition ratio 1. Urethane emulsion 80% by weight 2. Benzotriazole 5% by weight 3) Zinc oxide 10% by weight 4. Copper chloride 5% by weight

[0027] The coating agent prepared in Example 3 had the following properties: TIFF2025183124000003.tif42156 Example 4

[0028] The raw materials used for the ultraviolet absorbing coating agent were prepared according to the blending ratios shown below, and mixed and dispersed in a Henseshell mixer in the same manner as in Example 1 to obtain a coating agent, which was then evaluated for ultraviolet absorption, antibacterial properties, and antifungal properties.

[0029] Raw material composition ratio 1. Alkyl sulfate 40% by weight 2. Benzotriazole 5% by weight 3. Zinc oxide 10% by weight ▲4▼ Copper nitrate 1% by weight 5. Ethanol 44% by weight

[0030] The coating agent prepared in Example 4 had the following properties: TIFF2025183124000004.tif42156 Comparative example 1

[0031] The raw materials used for the ultraviolet absorbing coating agent were prepared according to the blending ratios below, and the coating agent was obtained by mixing and dispersing in the same manner as in Example 1, and the ultraviolet absorption, antibacterial performance, and antifungal performance were evaluated. The raw materials to be blended for the ultraviolet absorbing coating agent were as follows:

[0032] Raw material composition ratio 1. Acrylic emulsion 80% by weight 2. Benzotriazole 5% by weight 3. Ethanol 15% by weight

[0033] The coating agent prepared in Comparative Example 1 had the following properties. TIFF2025183124000005.tif42155 Comparative example 2

[0034] The raw materials used for the ultraviolet absorbing coating agent were prepared according to the blending ratios below, and the coating agent was obtained by mixing and dispersing in the same manner as in Example 1, and the ultraviolet absorption, antibacterial performance, and antifungal performance were evaluated. The raw materials to be blended for the ultraviolet absorbing coating agent were as follows:

[0035] Raw material composition ratio ▲1▼ Urethane emulsion 80% by weight 2. Benzotriazole 5% by weight ▲3▼ Water 15% by weight

[0036] The coating agent prepared in Comparative Example 2 had the following properties. TIFF2025183124000006.tif41156 Comparative example 3

[0037] The raw materials used for the ultraviolet absorbing coating agent were prepared according to the blending ratios below, and the coating agent was obtained by mixing and dispersing in the same manner as in Example 1, and the ultraviolet absorption, antibacterial performance, and antifungal performance were evaluated. The raw materials to be blended for the ultraviolet absorbing coating agent were as follows:

[0038] Raw material composition ratio ▲1▼ Acrylic silicone emulsion 80% by weight 2. Benzotriazole 5% by weight ▲3▼ Water 15% by weight

[0039] The coating agent prepared in Comparative Example 3 had the following properties. TIFF2025183124000007.tif41156 [Industrial Applicability]

[0040] The present invention relates to an ultraviolet-absorbing coating agent, which is used to maintain the beauty of the grain of wood such as plain wood and extend its lifespan by incorporating an organic ultraviolet absorber into a coating agent or paint that absorbs ultraviolet light. However, by using a zinc-based inorganic ultraviolet absorber in addition to this and by further incorporating a small amount of an antibacterial metal such as silver, it is possible to suppress the growth of black mold on the wood and solve the problem of discoloration and fading of plain wood. By applying the coating agent of the present invention to wood parts used as architectural structural materials in temples, shrines, hotels, hot spring facilities, etc., the beauty of new wood, especially plain wood, can be maintained for a long period of time. [Brief explanation of the drawings]

[0041] none

Claims

1. This method for extending the life of wood is characterized by preventing discoloration and fading of plain wood and suppressing the growth of black mold and blue mold by blending a small amount of antibacterial metal and antifungal metal into a coating agent or paint that absorbs ultraviolet light.

2. 2. A method for extending the life of wood, characterized in that the antibacterial metal and antifungal metal to be blended in the ultraviolet absorbing coating agent or paint of claim 1 are compounds of silver, copper, and zinc.

3. A method for extending the life of wood, characterized in that the antibacterial metals and antifungal metals contained in the ultraviolet-absorbing coating agent or paint of claims 1 and 2 are compounds of silver, copper, and zinc, with a content of 0.01% to 1.0%.

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