Painted body

Abstract

To provide a coating that exhibits excellent stain resistance against both water-based and oil-based stains. [Solution] A coated body comprising a substrate and a surface layer containing a resin, wherein the surface layer further comprises hydrophilic silica particles having a particle size of 70 nm or more and inorganic oxide particles different from the hydrophilic silica particles, and the ratio of the volume of the hydrophilic silica particles to the volume of the surface layer obtained by SEM-EDX analysis of the surface layer is 10% or more, and the ratio of the volume of the inorganic oxide particles to the volume of the surface layer is 10% or more.

Description

Technical Field

[0001] The present invention relates to a coated body having excellent antifouling properties.

Background Art

[0002] A technique for producing a coated body by providing a layer or film containing a substance having desired properties on a substrate and having the properties or functions exhibited by the properties is known. For example, attention is paid to hydrophobicity, water repellency, and / or oil repellency as desired properties, and functions such as the difficulty of dirt adhesion (poor adhesion) to the surface of the coated body and / or the ease of removing dirt from the surface of the coated body (easy removability or easy cleaning property) exhibited by these properties (poor adhesion and / or easy removability are referred to as "antifouling properties"). Coated bodies having such properties have been proposed.

[0003] For example, Japanese Patent Application Laid-Open No. 2007-238931 (Patent Document 1) describes that a hydrophobic coating film-forming composition containing a hydrophobic fine silica compound modified with hexamethyldisilazane was applied to the surface of a substrate (glass plate) to produce a functional material (coated body) (paragraph 0045, claim 6, etc.). According to Patent Document 1, the produced coated body is said to have good antifouling properties even after a two-week (3 rainy days) outdoor exposure test, and the hydrophobicity also persisted after being left for six months (paragraphs 0059 to 0060).

[0004] Furthermore, Japanese Patent Publication No. 2014-000697 (Patent Document 2) describes a resin substrate (biaxially oriented polyethylene terephthalate film) on one side, which contains (i) fine particles, specifically silica particles (average particle size of 100 nm, 50 nm, 10 nm, or 150 nm), alumina particles (average particle size of 100 nm), titanium oxide particles (average particle size of 100 nm), zinc oxide particles (average particle size of 100 nm), or zirconium oxide particles (average particle size of 100 nm) It is described that a layer was formed by applying a solution containing (ii) a binder, specifically a polymetalloxane (M=Si,Ti,Zr,Al) and (ii) a fluorine monolayer to the surface of this layer to form a fluorine monolayer, thereby producing water-repellent, oil-repellent, and antifouling films 2 to 15 ([Examples], Table 1). In Patent Document 2, the above layers and the above fluorine monolayer formed sequentially on the substrate are collectively referred to as the water-repellent and oil-repellent layer.

[0005] According to Reference 2, the water-repellent and oil-repellent antifouling films 2-15 comprise a water-repellent and oil-repellent layer in which a layer containing a polymetalloxane binder and fine particles is laminated with a fluorine monolayer. The surface of this water-repellent and oil-repellent layer has a specific uneven structure, i.e., an uneven structure with a root mean square roughness Rq of 10-45 nm. Furthermore, a fluorine-containing compound covers 69-91% of the surface area of ​​the water-repellent and oil-repellent layer. As a result, the contact angle between the film surface and water was 137° or higher immediately after film fabrication, and the contact angle remained 136° or higher even after xenon irradiation (Tables 1 and 2). Furthermore, Reference 2 suggests that there is a strong correlation between an Rq of 5-50 nm and excellent water- and oil-repellent properties (paragraph 0036), and that orienting fluorine-containing compounds to 70-95% of the surface of the water- and oil-repellent layer contributes to the development of superhydrophobicity (contact angle of 150° or more) (paragraph 0063). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2007-238931 [Patent Document 2] Japanese Patent Publication No. 2014-000697 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present inventors have now discovered a novel configuration for a coating that can exhibit excellent stain resistance against both water-based and oil-based stains. Specifically, in a coating comprising a substrate and a surface layer containing a resin, the inventors have found that by further including hydrophilic silica particles having a particle size of 70 nm or more and inorganic oxide particles different from those hydrophilic silica particles in the surface layer, and by controlling the proportion of each of the hydrophilic silica particles and inorganic oxide particles in the surface layer to 10% or more, excellent stain resistance against both water-based and oil-based stains can be achieved. The present invention is based on this finding.

[0008] Therefore, the object of the present invention is to provide a coated body that can exhibit excellent stain resistance against both water-based and oil-based stains. [Means for solving the problem]

[0009] Furthermore, the coating body according to the present invention is It comprises a base material and a surface layer containing resin, The surface layer further comprises hydrophilic silica particles having a particle size of 70 nm or more, and inorganic oxide particles different from those hydrophilic silica particles. The surface layer is analyzed by SEM-EDX and found to be composed of hydrophilic silica particles accounting for 10% or more of the total volume of the surface layer, and inorganic oxide particles accounting for 10% or more of the total volume of the surface layer. It is characterized by the following: [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing the basic structure of a coated body according to the present invention. [Figure 2] (a) A schematic diagram showing the structure of the surface layer of the coated body according to the present invention. (b) A schematic diagram showing the surface structure of the surface layer of the coated body according to the present invention, illustrating the ratio of the area occupied by hydrophilic silica particles on the surface of the surface layer to the total surface area of ​​the surface layer. [Figure 3] (i) This is an SEM image obtained by observing the coated body of Example 5 using SEM. (ii) This is a magnified image of region a, indicated by an ellipse in the SEM image. (iii) This is a magnified image of region b, indicated by an ellipse in the SEM image. [Figure 4] (a) SEM image obtained by observing the coated body of Example 5 with an SEM. (b) SEM-EDX image obtained by observing the coated body of Example 5 with an SEM and mapping the Si element with EDX. (c) SEM-EDX image obtained by observing the coated body of Example 5 with an SEM and mapping the Al element with EDX. [Figure 5] (a) SEM image obtained by SEM observation of the cross-section of the coated body of Example 5. (b) SEM-EDX image obtained by SEM observation and Si element mapping using EDX on the cross-section of the coated body of Example 5. (c) SEM-EDX image obtained by SEM observation and Al element mapping using EDX on the cross-section of the coated body of Example 5. [Figure 6] (a) SEM-EDX photograph obtained by SEM observation and EDX element mapping of the cross-section of the coated body of Example 5, with improved visibility of hydrophilic silica particles in this photograph. (b) SEM-EDX photograph obtained by SEM observation and EDX element mapping of the cross-section of the coated body of Example 5, with improved visibility of alumina particles in this photograph. [Modes for carrying out the invention]

[0011] Coating body according to the present invention The basic structure of the coated body according to the present invention will be described with reference to Figures 1 and 2. As shown in Figure 1, the coated body 1 according to the present invention comprises a substrate 2 and a surface layer 3. As shown in Figure 2a, the surface layer 3 contains a resin 4, hydrophilic silica particles 5 having a particle size of 70 nm or more, and inorganic oxide particles 6 different from the hydrophilic silica particles 5. Here, in this specification, "hydrophilic silica particles having a particle size of 70 nm or more" may also be simply referred to as "hydrophilic silica particles." In the present invention, the ratio of the volume of the hydrophilic silica particles 5 to the volume of the surface layer 3, obtained by SEM-EDX analysis of the surface layer 3, is 10% or more, and the ratio of the volume of the inorganic oxide particles 6 to the volume of the surface layer 3 is 10% or more. By having the above structure, the coated body according to the present invention can exhibit excellent resistance to adhesion and / or easy removal (easy cleaning), i.e., antifouling properties, against both water-based and oil-based stains. In this invention, the coated body 1 may have another layer (not shown) between the substrate 2 and the surface layer 3. The other layer may be, for example, a layer that has the function of improving the bonding strength between the substrate 2 and the surface layer 3, a layer that has the function of improving the strength or durability of the coated body 1, or a layer that has the function of improving or reinforcing the stain resistance of the surface layer 3.

[0012] The mechanism (action) that provides excellent stain resistance against both water-based and oil-based stains. The mechanism by which the coating body according to the present invention exhibits excellent stain resistance against both water-based and oil-based stains is thought to be as follows. Specifically, the hydrophilic silica particles 5 have properties that make them easily compatible with water and easily repel oil, thus making it difficult for oil-based stains to adhere to the surface 3S of the surface layer 3, and making it easier to remove oil-based stains from the surface 3S. Furthermore, by distributing the hydrophilic silica particles 5 and inorganic oxide particles 6 in the surface layer 3 in a specific volume ratio (both 10% or more) such that they are deposited on each other, and by setting the particle size of the hydrophilic silica particles 5 to a specific size (70 nm or more), it becomes possible to efficiently exhibit the stain resistance effect against oil-based stains by the hydrophilic silica particles 5 described above. At the same time, it becomes possible to form an uneven structure on the surface 3S of the surface layer 3 in which these particles (5, 6) are exposed, and which has recessed spaces that are fine and allow for the inclusion of sufficient air to efficiently repel water, water-based substances, oil, and oil-based substances, thus enabling good stain resistance against both water-based and oil-based stains. In other words, by distributing silica particles of a specific size and hydrophilicity in a specific volume ratio within the surface layer 3, and further distributing inorganic oxide particles together with the silica particles in a specific volume ratio, the surface properties of the surface layer 3 can be chemically and physically optimized, thereby enabling excellent stain resistance against both water-based and oil-based stains. It should be noted that the mechanism described above is merely a hypothesis, and the present invention is not limited in any way by this hypothesis.

[0013] The constituent components, surface properties, etc., of the surface layer of the coated body according to the present invention are described below.

[0014] Hydrophilic silica particles The surface layer included in the coated body according to the present invention contains hydrophilic silica particles. Since the hydrophilic silica particles are easily miscible with water and have the property of repelling oil, it is difficult for oily dirt to adhere to the surface of the surface layer, and it is also possible to easily remove the oily dirt from the surface of the surface layer. In the present invention, the "hydrophilic silica particles" means silica particles having a hydrophilic surface. Also, the hydrophilic surface means a surface having a hydrophilic functional group such as a silanol group or a hydroxyl group on the surface. Examples of the method for imparting hydrophilicity to the surface of the silica particles include a method of vaporizing silicon chloride and causing a gas-phase reaction in a high-temperature hydrogen flame, and a sol-gel method.

[0015] <Particle size> In the present invention, the hydrophilic silica particles have a particle size of 70 nm or more. Thereby, the effect of making it difficult for oily dirt to adhere to the surface of the surface layer and making it easy to remove the oily dirt from the surface of the surface layer, which the hydrophilic silica particles have, can be further enhanced. In the present invention, the upper limit of the particle size of the hydrophilic silica particles is preferably 120 nm or less, more preferably 110 to 115 nm or less, and even more preferably 100 nm or less. When the particle size of the hydrophilic silica particles is within the above range, not only can the poor adhesion and easy removability to oily dirt be further enhanced, but the hydrophilic silica particles can easily cooperate with the inorganic oxide particles to realize the desired surface properties. As a result, it is possible to exhibit good poor adhesion and easy removability to aqueous dirt, and excellent poor adhesion, easy removability, that is, excellent antifouling properties, can be exhibited against both oily dirt and aqueous dirt.

[0016] <Confirmation of the presence of hydrophilic silica particles, measurement of the particle size of hydrophilic silica particles> In the present invention, the confirmation that the hydrophilic silica particles 5 are contained in the surface layer 3 of the coated body 1 and the measurement of the particle diameter of the hydrophilic silica particles 5 can be carried out, for example, by the following method. For the coated body, from the vertical direction from the surface layer toward the base material, electron microscope observation and elemental analysis / mapping with Si contained in the hydrophilic silica particles, if necessary, are performed to confirm the presence of the hydrophilic silica particles and measure the particle diameter. The electron microscope observation can be carried out using a scanning electron microscope (SEM), and when observing at a higher magnification, a field emission scanning electron microscope (FE-SEM) can be used. The elemental analysis / mapping can be carried out using an energy dispersive X-ray detector (EDX). An apparatus in which EDX is attached to SEM or FE-SEM may also be used. As such an apparatus, Regulus8220 (manufactured by Hitachi High-Tech Corporation), which is an FE-SEM equipped with EDX, can be mentioned. SEM observation is performed to obtain a SEM image. By identifying the hydrophilic silica particles in this SEM image, it can be confirmed that the hydrophilic silica particles 5 are contained in the surface layer 3. An enlarged photograph of the region containing the identified hydrophilic silica particles is prepared, and the particle diameter of the identified hydrophilic silica particles can be measured. Alternatively, elemental analysis / mapping with Si contained in the hydrophilic silica particles is performed together with the SEM observation, and the confirmation of the presence of the hydrophilic silica particles and the measurement of the particle diameter can be performed more accurately or efficiently.

[0017] <Ratio of the volume occupied by the hydrophilic silica particles in the surface layer to the volume of the surface layer> (Measurement method) The ratio of the volume of hydrophilic silica particles 5 in the surface layer 3 to the volume of the surface layer 3 (hereinafter sometimes referred to as "volume ratio of hydrophilic silica particles to the surface layer" or simply "volume ratio of hydrophilic silica particles") can be measured as follows. That is, for the coated body 1, the volume ratio of hydrophilic silica particles can be measured by observing the cross-section with an electron microscope and performing elemental analysis mapping of the Si contained in the hydrophilic silica particles from a direction perpendicular to the direction from the surface layer to the substrate. Electron microscope observation and elemental mapping can be performed using a scanning electron microscope (SEM), a field emission scanning electron microscope (FE-SEM) for observation at higher magnification, and an energy-dispersive X-ray detector (EDX) (often attached to these SEMs). In the present invention, SEM observation and EDX elemental analysis of the surface or cross-section of the coated body is called SEM-EDX analysis.

[0018] (Suitable range of volume ratio of hydrophilic silica particles) In this invention, the volume ratio of hydrophilic silica particles is 10% or more. This not only enables excellent resistance to oily stains and easy removal, but also facilitates the achievement of desired surface properties through cooperation between the hydrophilic silica particles and inorganic oxide particles. As a result, good resistance to watery stains and easy removal are also achieved, enabling excellent resistance to both oily and watery stains, i.e., excellent antifouling properties. The volume ratio of hydrophilic silica particles is preferably 10% to 50%, and more preferably 10% to 40%. By controlling the volume ratio of hydrophilic silica particles within the above range, a good balance of antifouling properties against both watery and oily stains can be achieved.

[0019] <Ratio of the surface area of ​​hydrophilic silica particles to the surface area of ​​the surface layer> (Measurement method) The ratio of the area occupied by hydrophilic silica particles 5 on the surface 3S of surface layer 3 to the area of ​​surface 3S of surface layer 3 (hereinafter sometimes referred to as "area ratio of hydrophilic silica particles to the surface of the surface layer" or simply "area ratio of hydrophilic silica particles") can be measured as follows. That is, for the coated body 1, the area ratio of hydrophilic silica particles can be measured by performing electron microscope observation and elemental analysis mapping of the Si contained in the hydrophilic silica particles from a direction perpendicular to the direction from the surface layer toward the substrate. Electron microscope observation and elemental mapping can be performed using a scanning electron microscope (SEM), a field emission scanning electron microscope (FE-SEM) for observation at higher magnification, and an energy-dispersive X-ray detector (EDX) (often attached to these SEMs).

[0020] (Suitable range for the area ratio of hydrophilic silica particles) In this invention, the area ratio of hydrophilic silica particles is 20% or more. This not only enables excellent resistance to oily stains and easy removal, but also allows the hydrophilic silica particles to cooperate with inorganic oxide particles to easily achieve the desired surface properties. As a result, good resistance to watery stains and easy removal are also possible, enabling excellent resistance to both oily and watery stains, i.e., excellent antifouling properties. The area ratio of hydrophilic silica particles is preferably 20% to 50%, and more preferably 20% to 45%. By controlling the area ratio of hydrophilic silica particles within the above range, a good balance of antifouling properties against both watery and oily stains can be achieved.

[0021] Inorganic oxide particles The surface layer of the coated body according to the present invention contains inorganic oxide particles. The inorganic oxide particles work in cooperation with the hydrophilic silica particles described above to optimize the surface properties of the surface layer and contribute to the excellent antifouling properties of the coated body. Specifically, the inorganic oxide particles can impart a desired roughness and properties to the surface of the surface layer, and more specifically, they can form an uneven structure on the surface of the surface layer that allows air to enter, and the air that enters between the uneven surfaces repels both water-based and oil-based stains, that is, the surface of the surface layer can be given water-repellent and oil-repellent properties.

[0022] <Particle size> In the present invention, the inorganic oxide particles are preferably fine particles, and more preferably their particle size is smaller than that of the hydrophilic silica particles. The difference in particle size between the inorganic oxide particles and the hydrophilic silica allows for the formation of a surface with larger and rougher irregularities, which in turn allows more air to enter between the irregularities, resulting in a more water-repellent and oil-repellent surface. In the present invention, the particle size of the inorganic oxide particles is more preferably 10 nm or more and less than 70 nm, and even more preferably 10 nm or more and 50 nm or less, from the viewpoint that the effects of the present invention, namely excellent antifouling properties, are achieved through the cooperation of the hydrophilic silica particles and the inorganic oxide particles.

[0023] <Confirmation of the presence of inorganic oxide particles, measurement of the particle size of inorganic oxide particles> In the present invention, confirmation that inorganic oxide particles 6 are present in the surface layer 3 of the coated body 1, and measurement of the particle size of the inorganic oxide particles 6, can be performed, for example, by the following method. For the coated body 1, electron microscope observation and, if necessary, elemental analysis and mapping of the elements contained in the inorganic oxide particles can be performed from a direction perpendicular to the direction from the surface layer toward the substrate to confirm the presence of inorganic oxide particles and measure their particle size. Electron microscope observation can be performed using a scanning electron microscope (SEM) or a field emission scanning electron microscope (FE-SEM), and elemental analysis and mapping can be performed using an energy-dispersive X-ray detector (EDX). Perform SEM observation and obtain an SEM image. By identifying the inorganic oxide particles in this SEM image, it can be confirmed that inorganic oxide particles 6 are present in the surface layer 3. Prepare an enlarged photograph of the region containing the identified inorganic oxide particles, and measure the particle size of the identified inorganic oxide particles. Alternatively, elemental analysis and mapping of the elements contained in the inorganic oxide particles can be performed in conjunction with SEM observation to more accurately or efficiently confirm the presence of inorganic oxide particles and measure their particle size.

[0024] <Ratio of the volume of inorganic oxide particles in the surface layer to the total volume of the surface layer> (Measurement method) The ratio of the volume of inorganic oxide particles 6 to the volume of surface layer 3 (hereinafter sometimes referred to as "volume ratio of inorganic oxide particles to the surface layer" or simply "volume ratio of inorganic oxide particles") can be measured as follows. Specifically, for the coated body 1, the volume ratio of inorganic oxide particles can be measured by observing the cross-section with an electron microscope and performing elemental analysis mapping using elements such as Al contained in the inorganic oxide particles, from a direction perpendicular to the direction from the surface layer to the substrate. Examples of apparatus capable of performing electron microscopy observation and elemental mapping are as described above.

[0025] (Suitable range of volume ratio of inorganic oxide particles) In this invention, the volume ratio of inorganic oxide particles is 10% or more. This makes it possible to impart a desired surface property to the surface layer in cooperation with hydrophilic silica particles. In other words, it becomes possible to form an uneven structure on the surface of the surface layer that secures an uneven space that allows for the inclusion of sufficient air to efficiently repel water and aqueous substances as well as oil and oily substances, and it becomes possible to form such an uneven structure finely. As a result, excellent antifouling properties against both aqueous and oily stains can be achieved. The volume ratio of inorganic oxide particles is preferably 10% to 35%, and more preferably 10% to 30%. By controlling the volume ratio of inorganic oxide particles within the above range, a good balance of antifouling properties against both aqueous and oily stains can be achieved.

[0026] <Ratio of the surface area of ​​inorganic oxide particles to the total surface area of ​​the surface layer> (Measurement method) The ratio of the area occupied by inorganic oxide particles 6 on the surface 3S of surface layer 3 to the area of ​​surface 3S of surface layer 3 (hereinafter sometimes referred to as "area ratio of inorganic oxide particles to the surface of the surface layer" or simply "area ratio of inorganic oxide particles") can be measured as follows. That is, for the coated body 1, electron microscopy observation and elemental analysis mapping using, for example, Al contained in the inorganic oxide particles can be performed from a direction perpendicular to the direction from the surface layer toward the substrate to measure the area ratio of inorganic oxide particles. Examples of apparatus capable of performing electron microscopy observation and elemental mapping are as described above.

[0027] (Suitable range of area ratio of inorganic oxide particles) In this invention, the area ratio of inorganic oxide particles is 20% or more. This makes it possible to impart a desired surface property to the surface layer in cooperation with hydrophilic silica particles. In other words, it becomes possible to form an uneven structure on the surface of the surface layer that secures an uneven space that allows for the inclusion of sufficient air to efficiently repel water and aqueous substances as well as oil and oily substances, and it becomes possible to form such an uneven structure finely. As a result, excellent antifouling properties against both aqueous and oily stains can be achieved. The area ratio of inorganic oxide particles is preferably 20% to 50%, and more preferably 25% to 40%. By controlling the area ratio of inorganic oxide particles within the above range, a good balance of antifouling properties against both aqueous and oily stains can be achieved.

[0028] In the present invention, the inorganic oxide particles are preferably at least one particle selected from the group consisting of silica, titania, alumina, zirconia, magnesia, calcium oxide, and zinc oxide. By using inorganic oxide particles that are insoluble in water and have low reactivity to chemicals and stains, a highly durable uneven structure can be formed on the surface of the surface layer. As a result, it is possible to maintain excellent stain resistance against both water-based and oil-based stains over a long period of time.

[0029] (Suitable range for the sum of the volume ratio of hydrophilic silica particles and the volume ratio of inorganic oxide particles) In the present invention, the sum of the volume ratio of hydrophilic silica particles and the volume ratio of inorganic oxide particles is preferably 20-70%, more preferably 30-60%, and even more preferably 40-55%.

[0030] (Suitable range for the sum of the area ratio of hydrophilic silica particles and the area ratio of inorganic oxide particles) In the present invention, the sum of the area ratio of hydrophilic silica particles and the area ratio of inorganic oxide particles is preferably 40 to 90%, more preferably 50 to 85%, and even more preferably 60 to 75%.

[0031] Surface properties of the surface layer <Surface roughness> In the present invention, it is preferable that the arithmetic mean roughness Ra of the surface of the surface layer, as defined in JIS B 0601:2013, is 0.4 μm or more. Hydrophilic silica particles present in the above-mentioned area ratio on a surface having an uneven structure with an Ra of 0.4 μm or more can further enhance the antifouling effect against oily stains, and an uneven structure with an Ra of 0.4 μm or more makes it easier to secure fine uneven spaces on the surface of the surface layer that allow for the inclusion of sufficient air to efficiently repel water and aqueous substances, as well as oil and oily substances, thereby further enhancing the antifouling effect against both aqueous and oily stains.

[0032] <Water contact angle> In the present invention, it is preferable that the contact angle of water with respect to the surface of the surface layer is 100° or more. This makes it possible to lower the hydrophilicity of the surface layer, that is, to increase its water repellency, and in particular, to further improve the resistance to adhesion and ease of removal of water-based stains.

[0033] The contact angle of water with respect to the surface layer can be measured using a dynamic contact measurement system, for example, with a DCA-WZ type contact angle meter manufactured by Kyowa Interface Science Co., Ltd. For example, it can be measured with a drop volume of 2 μL of distilled water.

[0034] In the present invention, it is preferable that the surface layer does not contain fluorine or fluorine-containing compounds. For example, organofluorine compounds called PFAS have properties (hazardous properties) such as being difficult to decompose, highly bioaccumulative, and capable of long-distance transport. Furthermore, the diffusion of fluorine into the environment during the decomposition and disposal of fluorine-containing substances is a problem, and efforts regarding regulations and risk management are being made both domestically and internationally. Reducing the use of fluorine or fluorine-containing substances is a current social trend. As described above, the coated body according to the present invention can exhibit excellent stain resistance against both water-based and oil-based stains even without containing fluorine.

[0035] resin The surface layer of the coated body according to the present invention contains a resin. The resin functions as a binder, enabling the hydrophilic silica particles and inorganic oxide particles described above to be arranged in the surface layer. In the present invention, it is preferable that the resin is at least one hydrophobic resin selected from the group consisting of silicone resin, urethane resin, acrylic resin, vinyl chloride resin, olefin resin, and epoxy resin. This ensures adhesion between the surface layer and the substrate, water repellency of the surface of the surface layer, and durability of the surface layer.

[0036] A suitable example of a silicone resin is alkoxysilane. X-40-9300 (silicone resin, 100% solids content, manufactured by Shin-Etsu Chemical Co., Ltd.) is a suitable commercially available product. A suitable example of a urethane resin is polycarbonate diol. NY-333FT (urethane resin, 25% solids content, manufactured by DIC) is a suitable commercially available product. A suitable example of an acrylic resin is methacrylic acid ester. A suitable commercially available product is Acrydic WFL590 (acrylic resin, 60% solids content, manufactured by DIC). A suitable example of a vinyl chloride resin is vinyl chloride-acrylic acid ester copolymer. A suitable example of an olefin resin is ethylene vinyl acetate. A suitable example of an epoxy resin is polyethylene oxide.

[0037] Film thickness of the surface layer In the present invention, the thickness of the surface layer is not particularly limited, but is preferably 0.1 μm to 10 μm, more preferably 1 μm to 10 μm. By having the thickness of the surface layer within the above range, hydrophilic silica particles and inorganic oxide particles can be arranged on the surface layer to provide excellent stain resistance against both water-based and oil-based stains, and a desired surface texture (such as the uneven structure described above) can be imparted, while ensuring the durability of the surface layer and the good appearance of the coated body. The thickness of the surface layer can be measured, for example, by scratching the surface of the surface layer and observing the depth of this scratch with a laser microscope.

[0038] Base material The coated body according to the present invention includes a substrate. In the present invention, the substrate may be any material, whether inorganic or organic, as long as a surface layer containing resin can be formed on it, and its shape is not limited. Preferred examples of substrates from a material standpoint include metals, ceramics, glass, plastics, rubber, stone, cement, concrete, fibers, fabrics, wood, paper, combinations thereof, laminates thereof, and those having at least one coating on their surface. Preferred examples of substrates from an application standpoint include building materials, building interiors, window frames, window glass, structural members, vehicle interiors, interiors of machinery and articles, and interior materials in general such as films, sheets, and seals for attaching to the surface of the above articles. In the present invention, the substrate is preferably an interior material for buildings, and examples include wallpaper, flooring, toilets, bathtubs, unit bath walls, washbasins, faucets, mirrors, glass products, tiles, etc.

[0039] Purpose The coating according to the present invention exhibits excellent stain resistance against both water-based and oil-based stains, and is therefore preferably used for interior applications in buildings and the like. Interior materials to which the coating according to the present invention can be more preferably applied include wallpaper, flooring, toilets, bathtubs, unit bath walls, washbasins, faucets, mirrors, glass products, and tiles.

[0040] Manufacturing method of painted bodies The coated body according to the present invention can be manufactured, for example, by the following method.

[0041] Preparation of base material Prepare the base material. You can use the base material that has already been described.

[0042] Preparation of compositions for creating surface layers Prepare a composition for creating a surface layer.

[0043] Composition for creating a surface layer In another embodiment of the present invention, the present invention provides a composition for producing a surface layer. The composition according to the present invention is The resin comprises hydrophilic silica particles having a particle size of 70 nm or larger, and inorganic oxide particles different from those hydrophilic silica particles. The present invention is characterized in that the ratio of the solid content of the hydrophilic silica particles to the total solid content of the resin, hydrophilic silica particles, and inorganic oxide particles is 20% or more, and the ratio of the solid content of the inorganic oxide particles is 20% or more. The "resin," "hydrophilic silica particles having a particle size of 70 nm or larger," and "inorganic oxide particles" included in the composition have already been explained.

[0044] Concentration of hydrophilic silica particles contained in the composition In the present invention, the concentration of hydrophilic silica particles in the composition is such that, as described above, the ratio of the solid content of hydrophilic silica particles to the total solid content of the resin, hydrophilic silica particles, and inorganic oxide particles is 20% or more. As a result, the coated body according to the present invention can exhibit excellent stain resistance against both water-based and oil-based stains. The concentration of hydrophilic silica particles is preferably 20% to 60%, and more preferably 20% to 50%.

[0045] Concentration of inorganic oxide particles contained in the composition In the present invention, the concentration of inorganic oxide particles in the composition is such that, as described above, the ratio of the solid content of inorganic oxide particles to the total solid content of the resin, hydrophilic silica particles, and inorganic oxide particles is 20% or more. As a result, the coated body according to the present invention can exhibit excellent stain resistance against both water-based and oil-based stains. The concentration of inorganic oxide particles is preferably 20% to 70%, and more preferably 20% to 60%.

[0046] Concentration of resin contained in the composition In the present invention, the concentration of the resin in the composition is preferably such that the ratio of the solid content of the resin to the total solid content of the resin, hydrophilic silica particles, and inorganic oxide particles is 10% or more and 50% or less. This allows the resin to exhibit a good binder function that enables the hydrophilic silica particles and inorganic oxide particles to be distributed in the surface layer in the desired state, and in turn contributes to the excellent antifouling properties of the coated body according to the present invention against both water-based and oil-based stains. The concentration of the resin is more preferably 10% or more and 40% or less.

[0047] Materials containing hydrophilic silica particles In the present invention, hydrophilic silica particles can be added to the composition in the form of a material containing them. For example, hydrophilic silica particles may be included in the composition by adding them in the form of colloidal silica dispersed in a first dispersion medium (e.g., water), or in the form of an organosilica sol in which hydrophilic silica particles or the above colloidal silica is dispersed in a second dispersion medium (organic solvent). This ensures the dispersion stability of the colloidal silica or organosilica sol in the composition, and enables the distribution or arrangement of hydrophilic silica particles in the surface layer when a surface layer is formed from the composition, thereby enabling the development of excellent antifouling properties.

[0048] As the organosilica sol mentioned above, for example, you can use the organosilica sol listed on the Nissan Chemical Corporation website (https: / / www.nissanchem.co.jp / products / materials / inorganic / products / 02 / ). Specifically, examples include silica sols dispersed in hydrophilic solvents, specifically silica sols dispersed in methanol (methanol silica sol, MA-ST-M, MA-ST-L), silica sols dispersed in isopropyl alcohol (IPA-ST, IPA-ST-L, IPA-ST-ZL, IPA-ST-UP), silica sols dispersed in ethylene glycol (EG-ST-XL-30), silica sols dispersed in ethylene glycol mono-n-propyl ether (NPC-ST-30), silica sols dispersed in propylene glycol monomethyl ether (PGM-ST, PGM-ST-ZL, PGM-ST-UP), silica sols dispersed in dimethylacetamide (DMAC-ST, DMAC-ST-ZL), silica sols dispersed in N-methylpyrrolidone (NMP-ST); and silica sols dispersed in hydrophobic solvents (methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, propylene glycol monomethyl ether acetate, toluene). These organosilica sols may be used individually or in combination of two or more types.

[0049] Materials containing inorganic oxide particles In the present invention, the inorganic oxide particles described above are preferably added to the composition in the form of an aqueous colloid with water as the dispersion medium, or an organosol in which they are colloidally dispersed in a hydrophilic solvent such as ethyl alcohol, isopropyl alcohol, or ethylene glycol, similar to the hydrophilic silica particles.

[0050] solvent The composition for producing the surface layer may contain a solvent for dispersing a resin, hydrophilic silica particles having a particle size of 70 nm or more, and inorganic oxide particles in the composition. Such a solvent can be one of the well-known solvents commonly used for paints and coating compositions. Examples include water, n-butanol, and anone (cyclohexanone).

[0051] In the present invention, it is preferable to pre-treat the surface of the substrate before applying the composition to the substrate. For example, the surface of the substrate can be activated to improve the bonding strength between the substrate and the resulting surface layer. It is also preferable to clean the surface of the substrate beforehand. The method of cleaning is not particularly limited, but one example is cleaning using an appropriate cleaning solution.

[0052] Fabrication of the surface layer In the present invention, the method for producing the surface layer is not particularly limited as long as it is possible to form a stable layer on the substrate. For example, the surface layer may be formed by applying the above-described composition for producing the surface layer to the substrate and drying it. The method of applying the composition may be appropriately selected, and for example, methods such as roller, spray, roll coater, flow coater, dip coat, pour coating, screen printing, electrodeposition, and vapor deposition can be used. [Examples]

[0053] The present invention will be further described by the following examples, but the present invention is not limited to these examples.

[0054] material The following materials were prepared for the creation of the painted body.

[0055] As the base material, flooring material (457 x 457 x 2.5 mm, Sandstream IS-2034, Sangetsu) was prepared.

[0056] Composition for surface layer fabrication The following materials were prepared to create a composition for the surface layer. (1) Resin • Resin 1: X-40-9300 (Silicone resin, 100% solids content, manufactured by Shin-Etsu Chemical Co., Ltd.) • Resin 2: Acrydic WFL590 (acrylic resin, solid content concentration 60%, manufactured by DIC) • Resin 3: NY-333FT (urethane resin, solid content concentration 25%, manufactured by DIC) (2) Hydrophilic silica particles: IPA-ST-ZL (particle size 70-100 nm, solid content concentration 30%, manufactured by Nissan Chemical) (3) Inorganic oxide particles • Inorganic oxide particles 1: NAX50 (hydrophobic aerosil, solid content concentration 10%, particle size 30 nm, manufactured by Evonik) • Inorganic oxide particles 2: OZ-S30M (methanol-dispersed zirconia sol, solid content concentration 20%, particle size 50 nm, manufactured by Nissan Chemical) • Inorganic oxide particles 3: AS-520-A (hydrophilic alumina sol, solid content concentration 30%, particle size 30 nm, manufactured by Nissan Chemical) (4) Solvent • Solvent 1: n-butanol • Solvent 2: Butyl acetate • Solvent 3: Anone (cyclohexanone)

[0057] Preparation of a composition for surface layer fabrication Inorganic oxide particles 1 (5 g) were dispersed in solvent 1 (45 ml). To this dispersion (amount (g) as listed in Table 1), hydrophilic silica particles in the amount (g) listed in Table 1, one of resins 1 to 3 in the amount (g) listed in Table 1, solvent 2 (0.63 g), and solvent 3 were added so that the total volume of the solution was 12.5 g. The mixture was stirred using a stirrer at 25°C to prepare compositions for producing the surface layers of the coated bodies of Examples 1 to 3 and Comparative Examples 1 to 6. Furthermore, to one of the inorganic oxide particles 2 to 3 in the amount (g) listed in Table 1, hydrophilic silica particles in the amount (g) listed in Table 1, one of the resins 1 to 3 in the amount (g) listed in Table 1, solvent 2 (0.63 g), and solvent 3 so that the total liquid volume was 12.5 g, the mixture was stirred using a stirrer at 25°C to prepare the composition for producing the surface layer of the coated bodies of Examples 4 and 5. [Table 1]

[0058] The "volume" and "volume ratio" of inorganic oxide particles, hydrophilic silica particles, and resin listed in Table 1 are calculated values ​​obtained as follows. Volume = (Amount of ingredients × Solid content concentration / 100) / Density • Volume ratio = (Volume of inorganic oxide particles, hydrophilic silica particles, or resin) / (Total volume of inorganic oxide particles, hydrophilic silica particles, and resin)

[0059] Fabrication of painted body Apply the prepared surface layer composition to the surface of the prepared substrate at a rate of 10±1.0 g / m². 2 The coating was applied using a spray gun with the specified amount, and dried for 5 minutes in an electric furnace heated to 110°C to form a surface layer (coating film), thereby obtaining the coated bodies of Examples 1-5 and Comparative Examples 1-6.

[0060] evaluation The coated bodies of Examples 1-5 and Comparative Examples 1-6 were evaluated for the following items. The results are shown in Table 2. In Table 2, "Solid Content Ratio" refers to the amount of solids in each of the hydrophilic silica particles, inorganic oxide particles, and resin (the ratio of the latter to the former), when the total amount of solids in the above-mentioned surface layer composition, i.e., hydrophilic silica particles, inorganic oxide particles, and resin, is set to 100.

[0061] Confirmation of the presence of hydrophilic silica particles and measurement of their particle size. The presence and particle size of hydrophilic silica particles in the surface layer of the coated body of Example 5 were confirmed and measured by the following method. Specifically, the coated body was observed using a Regulus8220 field emission scanning electron microscope (FE-SEM) equipped with an energy-dispersive X-ray detector (EDX) (Hitachi High-Tech Corporation) from a direction perpendicular to the surface layer toward the substrate, and an SEM image was obtained (acceleration voltage: 6kV, magnification: 20.0k). In this SEM image, hydrophilic silica particles were identified based on the particle size information of the raw material hydrophilic silica particles, and the presence of hydrophilic silica particles was confirmed. An enlarged photograph of the region containing the identified hydrophilic silica particles (region a, shown as an ellipse in the SEM image) was prepared, and the particle size of the identified hydrophilic silica particles was measured. Figure 3i shows the SEM image obtained by observing the coated body of Example 5, and Figure 3ii shows the enlarged photograph prepared to measure the particle size of the hydrophilic silica particles. The particle sizes of the hydrophilic silica particles in this figure were, for example, 110 nm and 115 nm. These measured particle sizes were confirmed to be 70 nm or larger.

[0062] Confirmation of the presence of inorganic oxide particles and measurement of particle size. The presence and particle size of inorganic oxide particles 3 (aluminum oxide particles) contained in the surface layer of the coated body of Example 5 were confirmed and measured by the following method. The SEM image obtained when confirming the presence and particle size of hydrophilic silica particles contained in the surface layer of the coated body of Example 5, as described above, was used. In this SEM image, the inorganic oxide particles 3 were identified based on the particle size information of the raw material inorganic oxide particles 3, and their presence was confirmed. An enlarged photograph of the region containing the identified inorganic oxide particles 3 (region b shown as an ellipse in the SEM image) was prepared, and the particle size of the identified inorganic oxide particles 3 was measured. Figure 3iii shows the enlarged photograph prepared to measure the particle size of the inorganic oxide particles 3. In this figure, the particle sizes of the inorganic oxide particles 3 were, for example, 31.8 nm and 36.1 nm. These measured particle sizes were smaller than the particle size of the hydrophilic silica particles and were confirmed to be within the range of 10 nm to 50 nm.

[0063] Area ratio Area ratio of hydrophilic silica particles For the coated body of Example 5, the ratio (%) of the area of ​​the surface layer occupied by hydrophilic silica particles contained in the surface layer to the surface area of ​​the surface layer was measured by the following method. Specifically, for the coated body, SEM observation (acceleration voltage: 6kV, magnification: 20.0k) and Si element analysis / mapping were performed using the Regulus8220 from a direction perpendicular to the surface layer toward the substrate, and the area ratio of hydrophilic silica particles was measured from the mapped area of ​​silica particles containing Si elements. Figure 4a shows the SEM image obtained by SEM observation of the coated body of Example 5, and Figure 4b shows the SEM-EDX image obtained by Si element mapping. The area ratio of hydrophilic silica particles obtained from Figure 4b was 45%. This area ratio (45%) was confirmed to be an approximate value of the "solid content ratio" (40%) of hydrophilic silica particles listed in Table 2. Based on these verification results, for each coated body other than the coated body of Example 5, the "solid content ratio" of hydrophilic silica particles listed in Table 2 was considered to be the area ratio of hydrophilic silica particles.

[0064] Area ratio of inorganic oxide particles For the coated body of Example 5, the ratio of the area occupied by inorganic oxide particles 3 (aluminum oxide particles) contained in the surface layer to the surface area of ​​the surface layer was measured by the following method. Specifically, for the coated body, SEM observation (acceleration voltage: 6kV, magnification: 20.0k) and Al elemental analysis and mapping were performed using the Regulus8220 from a direction perpendicular to the surface layer toward the substrate. The area ratio of inorganic oxide particles 3 was measured from the mapped area of ​​inorganic oxide particles 3 that do not contain Si but contain Al. The SEM-EDX image obtained by Al elemental mapping is shown in Figure 4c. The area ratio of inorganic oxide particles 3 obtained from Figure 4c was 26%. It was confirmed that this area ratio (26%) is an approximate value of the "solid content ratio" (30%) of inorganic oxide particles 3 listed in Table 2. Based on these verification results, for each coated body other than the coated body of Example 5, the "solid content ratio" of the inorganic oxide particles (1, 2) listed in Table 2 was considered to be the area ratio of the inorganic oxide particles (1, 2).

[0065] Volume ratio Volume ratio of hydrophilic silica particles For the coated body of Example 5, the ratio of the volume of hydrophilic silica particles contained in the surface layer to the volume of the surface layer (coating film) was measured by the following method. The coated body of Example 5 was cut into 0.5 cm squares so as to include the cross-section of the surface layer, and sections were obtained. After fixing these sections with resin embedding, the cross-sections were polished using a polishing device. The polished cross-sections were observed using SEM (acceleration voltage: 6kV, magnification: 20.0k) and Si elemental analysis and mapping using the Regulus8220 mentioned above. The SEM image obtained from SEM observation of the polished cross-section is shown in Figure 5a, and the SEM-EDX images obtained from Si elemental mapping are shown in Figures 5b and 6a. Here, the SEM-EDX images shown in Figure 5b and the SEM-EDX images shown in the upper and middle sections of Figure 6a are the same. The SEM-EDX image shown in the lower part of Figure 6a shows the distribution of hydrophilic silica particles in the surface layer, made more visually apparent using software (Esprit ver. 1.9, Bruke). The percentage of hydrophilic silica particles in the coating film, obtained from the SEM-EDX image shown in the lower part of Figure 6a, was defined as the volume ratio of hydrophilic silica particles. The volume ratio of hydrophilic silica particles obtained from the SEM-EDX image shown in the lower part of Figure 6a was 37%. This volume ratio (37%) was confirmed to be an approximate value of the "volume ratio" of hydrophilic silica particles listed in Table 1 (calculated value: approximately 34%). Based on this confirmation, for each coating body other than the coating body of Example 5, the "volume ratio" of hydrophilic silica particles listed in Table 1 (calculated value) was considered to be the volume ratio of hydrophilic silica particles.

[0066] Volume ratio of inorganic oxide particles For the coated body of Example 5, the ratio of the volume of inorganic oxide particles 3 contained in the surface layer to the volume of the surface layer (coating film) was measured by the following method. The polished cross section prepared in the measurement of the volume ratio of hydrophilic silica particles described above was observed by SEM (acceleration voltage: 6kV, magnification: 20.0k) and Al elemental analysis and mapping using the Regulus8220. SEM-EDX images obtained by Al elemental mapping are shown in Figures 5c and 6b. Here, the SEM-EDX images shown in Figure 5c and the upper and middle SEM-EDX images shown in Figure 6b are the same. The SEM-EDX image shown in the lower part of Figure 6b shows the distribution of inorganic oxide particles 3 in the surface layer, made more visually apparent using software (Esprit ver.1.9, Bruker). The percentage of inorganic oxide particles 3 in the coating film obtained from the SEM-EDX image shown in the lower part of Figure 6b was defined as the volume ratio of inorganic oxide particles 3. The volume ratio of inorganic oxide particles 3, as determined from the SEM-EDX photograph shown in the lower part of Figure 6b, was 16%. This volume ratio (16%) was found to be close to the "volume ratio" of inorganic oxide particles 3 (calculated value: approximately 14%) listed in Table 1. Based on this confirmation, for each coated body other than the coated body of Example 5, the "volume ratio" (calculated value) of inorganic oxide particles (1, 2) listed in Table 1 was considered to be the volume ratio of inorganic oxide particles (1, 2).

[0067] Surface roughness The arithmetic mean surface roughness of the surface layer of each coated object was measured using a laser microscope (VK-X250, KEYENCE) in accordance with JIS B 0601:2013. The results are shown in Table 2.

[0068] contact angle The water contact angle with respect to the surface layer of each coated object was measured using a dynamic contact measurement system with a DCA-WZ type contact angle meter manufactured by Kyowa Interface Science Co., Ltd. The contact angle was measured by dropping 2 μL of distilled water onto the surface layer at a tilt angle of 0°, while the forward and backward angles were measured by discharging and aspirating 40 μL of distilled water at a rate of 20 μL / s. The results are shown in Table 2.

[0069] Film thickness of the surface layer The film thickness of the surface layer of each coated object was measured using the following method. Scratches were made on the surface of the surface layer, and the depth of these scratches was observed using a laser microscope (VK-X250, KEYENCE) and recorded as the film thickness of the surface layer. Three fields of view were randomly selected, and the film thickness was measured at three locations within each field of view. The average of the film thicknesses at a total of nine locations was recorded as the film thickness of the surface layer. The results are shown in Table 2.

[0070] Easy to clean The four types of contaminants (1g each) listed in Table 2 were applied to the surface of each coated object, dried at 25°C for 24 hours, and then subjected to a load of 100g / cm² using Keidry (manufactured by Nippon Paper Crecia Co., Ltd.). 2 The area was wiped five times with the appropriate force, and the remaining dirt was visually evaluated. The evaluation criteria were as follows: ○: There was no or very little remaining dirt. △: There was some remaining dirt, and the appearance was not good. ×: There was a lot of dirt remaining, and the appearance was poor.

[0071] [Table 2]

Claims

1. A coated body comprising a base material and a surface layer containing resin, The surface layer further comprises hydrophilic silica particles having a particle size of 70 nm or more, and inorganic oxide particles different from those hydrophilic silica particles. The surface layer is analyzed by SEM-EDX and found to be composed of hydrophilic silica particles accounting for 10% or more of the total volume of the surface layer, and inorganic oxide particles accounting for 10% or more of the total volume of the surface layer. A painted body characterized by the following features.

2. The coated body according to claim 1, wherein the arithmetic mean roughness Ra of the surface of the surface layer, as defined in JIS B 0601:2013, is 0.4 μm or more.

3. The coated body according to claim 1, wherein the contact angle of water with respect to the surface of the surface layer is 100° or more.

4. The coated body according to claim 1, wherein the particle size of the inorganic oxide particles is smaller than the particle size of the hydrophilic silica particles.

5. The coated body according to claim 1, wherein the inorganic oxide particles are at least one particle selected from the group consisting of silica, titania, alumina, zirconia, magnesia, calcium oxide, and zinc oxide.

6. The coated body according to claim 1, wherein the resin is at least one hydrophobic resin selected from the group consisting of silicone resin, urethane resin, acrylic resin, vinyl chloride resin, olefin resin, and epoxy resin.

7. The coated body according to claim 1, wherein the surface layer does not contain a fluorine-containing compound.

8. The coated body according to claim 1, wherein, as obtained by SEM-EDX analysis of the surface of the surface layer, the ratio of the area of ​​the hydrophilic silica particles to the surface area of ​​the surface layer is 20% or more, and the ratio of the area of ​​the inorganic oxide particles to the surface of the surface layer is 20% or more.

9. The resin comprises hydrophilic silica particles having a particle size of 70 nm or more, and inorganic oxide particles different from those hydrophilic silica particles. A composition characterized in that the ratio of the solid content of the hydrophilic silica particles to the total solid content of the resin, the hydrophilic silica particles, and the inorganic oxide particles is 20% or more, and the ratio of the solid content of the inorganic oxide particles is 20% or more.

10. A method for manufacturing a coated body according to claim 1, A manufacturing method characterized by comprising at least the step of applying the composition described in claim 9 to the surface of the substrate and drying it to form a surface layer.

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