Coating agent composition and production method therefor

Abstract

The present invention addresses the main problem of providing a coating agent composition for forming a coating layer that has high transparency, is extremely hydrophilic, and has an antifouling function and an antifogging function even in a low-temperature atmosphere. The present invention also addresses the problem of providing a method for producing the coating agent composition. Further, the present invention addresses the main problem of providing a product having a coating layer in which the coating agent is used.　Provided as means for solving said problems are: a production method for a coating agent composition, the method comprising (A) a step for causing a polymer obtained through polymerization of a silicon alkoxide to coexist with cerium hydroxide and / or cerium oxide to obtain an intermediate composition, and (B) a step for causing the intermediate composition obtained in said step (A) to coexist with an acidic colloidal silica to obtain a coating agent composition; and a coating agent composition comprising a polymer obtained through polymerization of a silicon alkoxide, cerium hydroxide and / or cerium oxide, and an acidic colloidal silica.

Description

Coating composition and method for producing the same

[0001] The present invention relates to a coating composition and a method for producing the same.

[0002] Conventional antifouling and antifogging coating layers provide antifouling functionality by imparting water repellency and hydrophilicity to the substrate surface, thereby preventing adhesion of contaminants and providing a self-cleaning effect with water. However, many of the coating agents used in these applications are solvent-based, which is undesirable from the perspective of environmental protection these days. Therefore, there is a demand for solvent-free antifouling coating agents. However, it has been difficult to form thin films of 0.4 μm or less with water-based coating agents. Furthermore, there have been no one-component coating agents that can be stored for long periods of time.

[0003] When a coating agent is used outdoors, it must be cured at room temperature, but water-based coating agents do not adhere well to substrates, and adhesion to plastic products in particular is poor.

[0004] Imparting water repellency prevents water from adhering to the coating layer, thereby providing antifouling properties. Furthermore, imparting hydrophilicity and water absorption properties allows the thin water film on the substrate surface and the absorbed water to exhibit hydrophilicity, washing away adhering dirt by running water, thereby providing antifouling properties. On the other hand, regarding the antifogging effect, trace amounts of water vapor in the water-repellent film adhere to the substrate surface, causing diffuse reflection of light and resulting in fogging. Furthermore, when the hydrophilic film contains little water, a small amount of dirt adheres to the surface, causing fogging. Furthermore, the adhering dirt penetrates into the coating layer due to static electricity in the coating layer, reducing its antifogging properties. Furthermore, when a water-absorbent coating layer contains water, its water resistance and adhesion decrease, accelerating the deterioration of the coating layer.

[0005] Antifouling and antifogging coating agents containing tin oxide-based inorganic ultrafine particles are known to reduce the surface resistance of the substrate and improve adhesion to the substrate (see, for example, Patent Document 1). However, reducing the surface resistance of the substrate requires the addition of a large amount of tin oxide-based ultrafine particles, which reduces hydrophilicity and adhesion, making it difficult to produce a coating layer that combines stable antifouling and antifogging properties.

[0006] Furthermore, conventional anti-fog coating layers (e.g., Patent Document 2) cause fogging when one side of a transparent substrate is at a temperature below freezing and the other side is at room temperature. Furthermore, when the temperature of the transparent substrate is lowered to below freezing and then returned to room temperature, the substrate becomes fogging. Furthermore, when the antifouling and anti-fog coating layer applied to the transparent substrate absorbs water, the absorbed water freezes below freezing, causing fogging due to crystallization.

[0007] JP 2008-208241 JP 05-222338

[0008] An object of the present invention is to provide a coating composition that forms a coating layer that is highly transparent, superhydrophilic, and has antifouling and antifogging properties even in a low-temperature atmosphere. Another object of the present invention is to provide a method for producing this coating composition. A further object of the present invention is to provide a product having a coating layer using this coating agent.

[0009] The present inventors have conducted extensive research to solve the above problems and have completed the present invention.

[0010] That is, the present invention includes the following embodiments. Item 1. A method for producing a coating composition, comprising: (A) a step of obtaining an intermediate composition by bringing a polymer obtained by polymerizing silicic acid alkoxide into the presence of cerium hydroxide and / or cerium oxide; and (B) a step of obtaining a coating composition by bringing the intermediate composition obtained in step (A) into the presence of acidic colloidal silica. Item 2. The production method according to item 1, further comprising a step of obtaining the polymer having a 3-polymer to 40-polymer structure by polymerizing the silicic acid alkoxide before step (A). Item 3. The production method according to item 1 or 2, wherein the silicic acid alkoxide is tetramethoxysilane and / or tetraethoxysilane. Item 4. The production method according to any one of items 1 to 3, wherein the cerium hydroxide and / or cerium oxide is a ceria sol having a particle size of 100 nm or less and a cerium concentration of 50% by weight or less in terms of cerium oxide. Item 5. Item 6. The manufacturing method according to any one of Items 1 to 4, further comprising, after step (B), a step of bringing the coating agent composition and a surfactant into coexistence to obtain a further processed coating agent composition. Item 7. The manufacturing method according to any one of Items 1 to 6, further comprising, after step (B), a step of bringing the coating agent composition or the further processed coating agent composition into coexistence with tin oxide-based microparticles to obtain a further processed coating agent composition. Item 8. The manufacturing method according to any one of Items 1 to 7, further comprising, after step (B), a step of bringing the coating agent composition or the further processed coating agent composition into coexistence with a water-based binder resin component to obtain a further processed coating agent composition. Item 9. Item 10. A coating composition comprising a polymer obtained by polymerizing silicic acid alkoxide, cerium hydroxide and / or cerium oxide, and acidic colloidal silica. Item 11. The coating composition according to Item 9, wherein the polymer obtained by polymerizing silicic acid alkoxide is a 3-polymer to 40-polymer.Item 11. The coating composition according to Item 9 or 10, wherein the silicate alkoxide is tetramethoxysilane and / or tetraethoxysilane. Item 12. The coating composition according to any one of Items 9 to 11, wherein the cerium hydroxide and / or cerium oxide is a ceria sol having a particle diameter of 100 nm or less and a cerium concentration of 50% by weight or less in terms of cerium oxide. Item 13. The coating composition according to any one of Items 9 to 12, wherein the light transmittance is 80% or more. Item 14. The coating composition according to any one of Items 9 to 13, further comprising a surfactant. Item 15. The coating composition according to any one of Items 9 to 14, further comprising tin oxide-based fine particles. Item 16. The coating composition according to any one of Items 9 to 15, further comprising an aqueous binder resin component. Item 17. The coating composition according to any one of Items 9 to 16, further comprising a water-soluble solvent and / or water. Item 18. Item 18. A coated article having a coating layer comprising the coating composition according to any one of items 9 to 17.

[0011] The present invention can provide a coating composition that is highly transparent, superhydrophilic, and has antifouling and antifogging properties even in a low-temperature atmosphere. The present invention also provides a method for producing such a coating composition.

[0012] <Definition of Terms> In this specification, the term "coating composition" means a composition that forms a coating layer by being applied to the surface of a substrate such as glass, metal, or plastic, and that provides effects such as protection of the substrate surface, a glossy effect, an antifouling effect, or a water-repellent effect, depending on the purpose.

[0013] As used herein, the term "ceria sol" refers to a sol dispersion containing cerium hydroxide and / or cerium oxide as fine particles.

[0014] As used herein, the term "colloidal silica" refers to fine particles of silica (silicon dioxide) dispersed in a solvent. Silica is usually amorphous, its particle size is usually about 10 to 300 nm, and it is dispersed in a colloidal state.

[0015] 1. Step (A) The silicate alkoxide used in the present invention is not particularly limited and may have any alkoxy group. Among them, silicate alkoxides having an alkoxy group having 1 to 4 carbon atoms, such as a methoxy group or an ethoxy group, are preferred because they are liquid at room temperature. Examples of such silicate alkoxides include tetramethoxysilane and tetraethoxysilane.

[0016] When polymerizing the silicic acid alkoxide used in the present invention, one type or a mixture of two or more types may be used. The condensation reaction may be carried out by a known method, for example, by a dehydration reaction or a dealcoholization reaction after a hydrolysis reaction. For these reactions, water, an organic solvent, a catalyst, etc. may be used as appropriate. The degree of polymerization of the polymer after the reaction is not particularly limited, but a polymer with a polymerization degree of 3 to 40 is preferred to achieve a viscosity suitable for a coating composition. The polymer may also be mixed with a water-soluble solvent, water, etc. as appropriate.

[0017] The form of the cerium hydroxide and / or cerium oxide used in the present invention is not particularly limited, and may be, for example, powder. However, from the viewpoint of dispersibility, it is preferable to use the form of a ceria sol dispersed in a water-soluble solvent, water, or the like. When the cerium hydroxide and / or cerium oxide is in the form of a ceria sol, the solation may be carried out by a known method. A suitable ceria sol can be obtained when the cerium hydroxide and / or cerium oxide has a particle diameter of 100 nm or less and a cerium concentration of 50 wt % or less in terms of cerium oxide.

[0018] In step (A), the coating composition or the further processed coating composition may be further processed by adding another metal alkoxide to the coating composition. Examples of the metal alkoxide include aluminum compounds, titanium compounds, and zirconium compounds. These compounds are thought to act as curing catalysts.

[0019] In the present invention, the mixing means may be agitation, shaking, ultrasonic dispersion or the like, and may be appropriately selected depending on the reaction scale.

[0020] 2. Step (B) The colloidal silica used in the present invention can be, for example, one dispersed in a water-soluble solvent or water. The particle size is not particularly limited, but from the viewpoint of dispersibility, it is preferable that the colloidal silica be spherical with a particle size of 100 nm or less, or nanoparticles in which spherical particles are linked in a chain shape. In order to maintain the stability of the coating composition, it is preferable to use acidic colloidal silica.

[0021] When acidic colloidal silica is directly mixed with cerium hydroxide and / or cerium oxide, a white gel substance is formed, impairing transparency; therefore, cerium hydroxide and / or cerium oxide can only be mixed in an amount of approximately 0.5% to 3% by solids content. In this regard, the present inventors discovered that by coexisting a composition in which a polymer obtained by polymerizing silicic acid alkoxide and cerium hydroxide and / or cerium oxide coexist with acidic colloidal silica, the amount of cerium hydroxide and / or cerium oxide that can be incorporated can be increased without impairing the transparency of the coating composition. According to the present invention, coating compositions containing up to approximately 30% by solids content of cerium hydroxide and / or cerium oxide can be produced depending on the application.

[0022] 3. Additional Steps The manufacturing method of the present invention may further include a dilution step, a step of adding additional additives, etc., to produce a coating composition suited to the intended use. The additional steps are not particularly limited as long as they do not impair the properties of the coating composition of the present invention. The manufacturing method of the present invention may include multiple, identical or different, additional steps, and the order of these steps is not limited. Examples of additional steps are given below, but the present invention is not limited by these examples.

[0023] The production method of the present invention may further include, after step (B), a step of obtaining a further processed coating composition by allowing the coating composition or the further processed coating composition to coexist with a surfactant. The surfactant improves the wettability of the coating composition of the present invention to a substrate. The form of the surfactant is not particularly limited and may be a solid, liquid, a mixture with a water-soluble solvent and / or water, etc. When the water content of the coating composition of the present invention is high, the surface tension increases and the wettability to the substrate deteriorates. In particular, when the water content is 70% or more, it is preferable that the coating composition contains a surfactant.

[0024] The surfactant used in the present invention is not particularly limited, and either an ionic surfactant or a nonionic surfactant can be used, but it is preferable that the surfactant can improve the wettability of the coating composition and maintain transparency when contained in an amount of 0.5 wt% or less relative to the coating composition. In addition, it is particularly preferable to use a nonionic surfactant because it does not affect the dispersibility of the solid components of the coating composition. Among them, acetylene glycol-based surfactants are particularly preferable because they not only improve wettability with a small amount but also improve the antifouling and antifogging properties of the coating composition.

[0025] The manufacturing method of the present invention may further include, after step (B), a step of obtaining a further processed coating composition by bringing the coating composition or the further processed coating composition into the presence of tin oxide-based microparticles. The form of the tin oxide-based microparticles is not particularly limited, and may be a solid, a mixture with a water-soluble solvent and / or water, or the like. The tin oxide-based microparticles improve the adhesion of the coating composition to the substrate and also suppress the adhesion of dirt due to their antistatic effect.

[0026] The tin oxide-based fine particles used in the present invention are not particularly limited, but preferably contain antimony-doped tin oxide and / or indium-doped tin oxide. In order to maintain the transparency of the coating composition, the tin oxide-based fine particles preferably have a particle size of 100 nm or less, and particularly preferably 50 nm or less.

[0027] The manufacturing method of the present invention may further include, after step (B), a step of obtaining a further processed coating composition by coexisting the coating composition or the further processed coating composition with an aqueous binder resin component. The form of the aqueous binder resin component is not particularly limited and may be a solid, a mixture with a water-soluble solvent and / or water, or the like. When the coating composition contains an aqueous binder resin component, it exhibits excellent adhesion to resin substrates and is less likely to peel. The aqueous binder resin is selected depending on the type of resin of the substrate, and one with excellent adhesion to the substrate may be selected. For example, water-dispersible polyester resin emulsions, water-soluble self-reactive acrylic resins, water-dispersible chlorinated propylene resin emulsions, etc. are used for polyethylene terephthalate films, vinyl chloride films, polyolefin films, polypropylene films, and various other films.

[0028] It is known that the dispersibility of aqueous binder resin components is improved in the presence of tin oxide-based fine particles. In such cases, the aqueous binder resin component is preferably contained in an amount of 0.3 to 10 parts by weight, more preferably 0.8 to 8 parts by weight, per 100 parts by weight of tin oxide-based fine particles. If the aqueous binder resin component is contained in an amount of less than 0.3 parts by weight, the adhesion to the substrate and water resistance will decrease, and the composition will be more likely to peel off from the substrate.

[0029] The stability of the coating agent composition of the present invention decreases when the concentration of solid components is high. Therefore, the production method of the present invention may further include a step of obtaining a further processed coating agent composition by bringing the coating agent composition or the further processed coating agent composition into the presence of a water-soluble solvent and / or water.

[0030] The water-soluble solvent used in the present invention is not particularly limited, and examples thereof include alcohols such as ethanol and glycol ethers. Furthermore, the form of the water-soluble solvent is also not particularly limited, and it may be a mixture with water or a different water-soluble solvent. If the content of the water-soluble solvent in the coating composition is high, it is considered a hazardous material and storage and handling are restricted. Therefore, it is preferable that the content of the water-soluble solvent is low and the content of water is high. The content of water is preferably 50% or more, more preferably 70% or more, and particularly preferably 80% or more, relative to the coating composition.

[0031] The production method of the present invention may further include a step of obtaining a further processed coating composition by adding a dye, antioxidant, lubricant, stabilizer, thickener, pH adjuster, UV absorber, flame retardant, etc. to the coating composition or a further processed coating composition, as long as the properties of the coating composition of the present invention are not impaired. The types of these additives are not particularly limited. Furthermore, the form of these additives is not particularly limited and may be a solid, liquid, a mixture with a water-soluble solvent and / or water, etc.

[0032] 4. Coating Composition The present invention also encompasses a coating composition containing a polymer obtained by polymerizing silicate alkoxide, cerium hydroxide and / or cerium oxide, and acidic colloidal silica.

[0033] The coating layer formed by the coating composition of the present invention preferably has high transparency and does not reduce the transmittance of the transparent substrate. The transmittance is preferably 80% or more, more preferably 90% or more, even more preferably 95% or more, and particularly preferably 98% or more, in a thin film of 0.4 μm. Furthermore, the coating composition of the present invention contains ceria sol with a high refractive index, which increases the reflectance, so that when the coating composition is applied to a black base, it has little effect on the color of the substrate. On the other hand, the coating layer formed by the coating composition of the present invention may have low transparency and may be colored with a dye or the like, as long as its antifouling and antifogging properties are maintained.

[0034] The coating layer formed by the coating agent composition of the present invention has very high hydrophilicity and exhibits antifouling and antifogging properties. Therefore, the contact angle of the coating layer with water is preferably 30° or less, more preferably 15° or less, and particularly preferably 5° or less.

[0035] The composition ratio of the coating composition of the present invention is not limited as long as the properties of the coating composition are not impaired, and the composition ratio of the polymer obtained by polymerizing silicic acid alkoxide, cerium hydroxide and / or cerium oxide, and acidic colloidal silica is preferably 460:3:537 to 385:167:448, and more preferably 459:6:535 to 448:30:522, in terms of solid content ratio.

[0036] From the viewpoint of safety and stability of the coating composition of the present invention, the water content is preferably high, and the water content is preferably 50% by weight or more, more preferably 70% by weight or more, and particularly preferably 80% by weight or more, based on the weight of the coating composition.

[0037] Furthermore, the coating composition of the present invention preferably contains a surfactant to improve wettability. The content of the surfactant is not limited as long as the properties of the coating composition of the present invention are not impaired, and is preferably 1 wt % or less, particularly preferably 0.5 wt % or less, based on the coating composition.

[0038] The coating composition of the present invention may further contain tin oxide-based fine particles. The content thereof is not limited as long as the properties of the coating composition of the present invention are not impaired, and is preferably 1 to 20% by weight, particularly preferably 3 to 10% by weight, based on the coating composition.

[0039] The coating composition of the present invention may further contain an aqueous binder resin component. The content thereof is not limited as long as the properties of the coating composition of the present invention are not impaired, and is preferably 0.3 to 20% by weight, particularly preferably 0.5 to 3% by weight, based on the coating composition.

[0040] 5. Coated Articles The present invention also encompasses coated articles having a coating layer containing the coating composition of the present invention. The substrates used for coated articles are not particularly limited, and examples thereof include plastic films, Plasx resin plates and molded products thereof, metals, glass, ceramics such as cement, and ceramic molded products thereof.

[0041] The method for applying the coating composition to the substrate is not particularly limited, and examples thereof include spray coating, dip coating, brush coating, gravure roll coating, reverse roll coating, lip coating, air knife coating, wire bar coating, curtain flow coating, etc. Furthermore, it also includes laminating a plastic film having a pressure-sensitive adhesive applied to one side thereof to the substrate, and then applying the coating composition thereto. It also includes providing an undercoat of another coating composition on the substrate, and then applying the coating composition of the present invention thereon.

[0042] The coating composition of the present invention can usually be cured at room temperature, between 10°C and 40°C. At room temperature, a coating layer is usually formed after drying for 3 hours or more. Heat curing may also be performed to accelerate the curing time. In this case, it is preferable to perform heat treatment at 40°C or higher within the range that the substrate can withstand. Furthermore, if it is difficult to form a coating layer, it is preferable to perform heat treatment at 80°C or higher within the range that the substrate can withstand. In this case, treatment at 100°C or higher for about 30 seconds to 2 minutes is preferable. On the other hand, it is necessary to select a heating temperature and heating time within a range that does not impair the properties of the coating layer, and a heating temperature of 120°C or lower is preferred.

[0043] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to these examples in any way.

[0044] 1. Light Transmittance: Light transmittance was measured using a UV-Visible Spectrophotometer V-530 (manufactured by JASCO Corporation). 2. Contact Angle and Hydrophilicity: Contact angle and hydrophilicity were evaluated using a portable contact angle meter PG-X+ (manufactured by Matsubo Corporation). 3. Antifouling Test: The antifouling test was commissioned to the Civil Engineering Research Center and conducted in accordance with Accelerated Test Method III for Antifouling Materials. A material is deemed to meet Class III civil engineering antifouling standards if its lightness difference ΔL is -3.20 or greater and its post-test transmittance is 66.0% or greater. 4. Adhesion: Adhesion was evaluated using a 10 x 10 grid test and a pencil scratch test in accordance with JIS K 5400:1990. 5. Antifogging: Antifogging properties against hot water vapor were evaluated by placing hot water (90°C or higher) in a container, holding a sample over the container, and observing the fogging. Next, the anti-fogging property against a temperature change from low temperature to room temperature was evaluated by cooling the sample to -20°C or below and then taking it out at room temperature of 20°C, and observing the fogging.

[0045] Example 1 Coating Composition A 100 g of tetraethoxysilane was condensed in water, ethanol, and hydrochloric acid to prepare 150 g of 10-polymer siloxane polymer (20 wt.% solids). 60 g of ethanol was added to the polymer, and 150 g of acidic colloidal silica (15 wt.% solids) (ST-OUP, Nissan Chemical Industries, Ltd.) was added to partially react to prepare a coating composition. 0.2 wt. % of the nonionic surfactant Olfine (Shin-Etsu Chemical Co., Ltd.) was added to the coating composition. Water was then added to obtain a room-temperature curing coating composition A with a solids content of 1.5%.

[0046] Coating composition B: 100g of tetraethoxysilane was condensed in water, ethanol, and hydrochloric acid to produce 150g of 10-polymer siloxane polymer (20% solids by weight). 3g of an aqueous ceria sol solution (30% solids by weight) (Daiichi Kigenso Kagaku Kogyo) was added to the polymer, and 150g of acidic colloidal silica (15% solids) was added to partially react to prepare a coating composition. 0.2% by weight of the nonionic surfactant Olfine was added to the coating composition. Water was then added to obtain room-temperature curing coating composition B with a solids content of 1.5%.

[0047] The coating composition A or B was applied to float glass (lime glass) used for glass, window glass, door glass, etc. in houses and buildings to form a coating layer, thereby preparing a sample.

[0048] Various evaluations were carried out on the obtained samples. The results are shown in Table 1. Untreated glass has low hydrophilicity, resulting in low antifouling and antifogging properties. Glass coated with Coating Agent A has a transparent, hydrophilic coating layer, but low antifogging properties. The coating layer with Coating Agent B is ultrahydrophilic, resulting in a coating layer that combines excellent antifouling and antifogging properties. The above coating agents were also applied to the front glass, rear glass, and window glass of laminated glass for automobiles, and the results were almost the same. Glass used in automobiles in particular requires low-temperature antifogging properties, and the coating layer with Coating Agent B is optimal.

[0049]

[0050] Example 2 Coating agents A and B used in Example 1 were applied to a mirror. Because mirrors reflect light, even a small amount of water droplets will cause fogging. The results are shown in Table 2. Untreated mirrors fog up because steam adheres to the mirror surface as water droplets. Mirrors coated with coating agent A fog up slightly when steam adheres, causing diffuse reflection of light. However, when a large amount of water is poured onto the mirror surface, a uniform water film is formed on the mirror surface, and even if steam comes into contact with this, it is absorbed by the water film, maintaining anti-fogging properties for about an hour. The mirror coated with coating agent B has very high hydrophilicity, and does not form water droplets even when it comes into contact with steam, maintaining anti-fogging properties.

[0051]

[0052] Example 3: A room-temperature curing coating composition with a solids content of 1% was prepared in the same manner as Coating Agent B in Example 1. After the paint had sufficiently dried, the coating composition was applied to the exterior painted surface of a detached house using an air spray and then dried at room temperature. A crane truck was used for the coating. No discoloration was observed on the exterior paint (white) left outdoors for three years after application. Conventional coating agents that combine colloidal silica with siloxane polymers have a low refractive index of 1.43, which increases light absorption and discolors dark black paints. This coating composition contains ceria sol, which has a high refractive index, and was found to have the effect of increasing light reflectance. Therefore, this coating composition does not cause discoloration when applied to black surfaces.

[0053] Example 4 A room-temperature curing coating composition with a solids content of 1% was prepared in the same manner as Coating Agent B in Example 1. The coating composition was placed in a dipping tank, and an air conditioning equipment part composed of an aluminum fin and a copper pipe was immersed and then removed. The coating liquid was then applied thinly and evenly by rotation and vibration. To shorten the curing time, hot air drying was performed at 100°C. As a result, hydrophilicity was imparted, and a thin water film suppressed the adhesion of water droplets to the aluminum fin. This accelerated the evaporation of the water film, improving the cooling efficiency of the air conditioner.

[0054] Example 5 Coating Composition C As with Coating Composition B, a coating composition was prepared by partially reacting a siloxane polymer of 10-polymerized tetraethoxysilane with an aqueous ceria sol solution and acidic colloidal silica. A composition (solids content 10% by weight) containing a polyester resin emulsion and water-dispersed tin oxide ultrafine particles (Unitika Ltd.) was diluted with water to prepare an aqueous composition with a solids content of 2% by weight. 0.2% by weight of the nonionic surfactant Olfine and 20% by weight of the aqueous composition were added to the coating composition. Further water was added to obtain a room-temperature curing coating composition C with a solids content of 1.5%.

[0055] The above coating composition C was applied to one side of a 50 μm thick PET film and heated at 110° C. for 20 minutes to accelerate curing, forming a coating layer. An adhesive was applied to the other side, and release paper was attached. By laminating this transparent, antifouling, and antifogging PET film to a transparent substrate, it is possible to provide a transparent functional product with antifouling and antifogging properties.

[0056] Coating Composition D: Similar to Coating Composition B, a coating composition was prepared by partially reacting a siloxane polymer of tetraethoxysilane 10 polymer, an aqueous ceria sol solution, and acidic colloidal silica. A composition containing a polyetheresteramide resin component and water-dispersed tin oxide ultrafine particles (Unitika Ltd.) was diluted with water to prepare an aqueous composition. 0.2 wt. % of the nonionic surfactant Olfine (Nissin Chemical Industry Co., Ltd.) and 20 wt. % of the aqueous composition were added to the coating composition. Further water was added to obtain Coating Composition D with a solids content of 3%. Coating Composition D was applied to a PET film and heated at 110°C for 1 minute to form an excellent anti-fog coating layer. However, it cannot be cured at room temperature.

[0057] The results of applying Coating Composition C to a PET film, with Coating Composition A as a control, are shown in Table 3. When Coating Composition A was applied directly to a PET film, it was found to have poor adhesion, easy peeling, and poor anti-fogging properties. Coating Composition C, which contains tin oxide ultrafine particles with low surface resistance, has good adhesion to the PET film and exhibits excellent anti-fogging properties.

[0058]

[0059] Furthermore, the PET film coated with Coating Composition C was attached to various substrates, and the performance was evaluated. The results are shown in Table 4.

[0060]

[0061] Example 6 The performance of a coating composition applied to an agricultural vinyl film was examined.

[0062] Agricultural polyvinyl chloride film (PVC film) suffers from the bleed-out phenomenon of plasticizers. To address this issue, acidic colloidal silica (20% solids) was added to a water-based acrylic resin (U-Double, Nippon Shokubai Co., Ltd.) at a solids ratio of 30%, and the resulting solution was further diluted to a solids content of 3%. This solution was then applied to the PVC film as an undercoat. Coating composition B was then applied over the film, which had been dried at 50°C for 10 minutes, and heated at 50°C for 10 minutes to form a coating layer.

[0063] Polyolefin films (PO films) have poor adhesion to coating composition B. Therefore, 30% acidic colloidal silica and 0.2% nonionic surfactant were added to a composition (10% solids content) containing an acid-modified polyolefin / ether block polymer and tin oxide (Unitika Ltd.), and the mixture was diluted with water to prepare an aqueous solution with a solids content of 3%. This was used as an undercoating agent. Furthermore, a coating composition with a solids content of 3% was prepared in the same manner as coating composition B, and 30% of the undercoating agent was added in solids content. This was then diluted with water to obtain a coating composition with a solids content of 1.5%. The undercoating agent was applied to a PO film and heated at 110°C for 30 seconds. The coating composition was then applied again and heated at 110°C for 30 seconds to form a coating layer.

[0064] The evaluation results are shown in Table 5. This coating composition imparted antifouling and antifogging properties to the agricultural film, thereby preventing a decrease in light transmittance due to contamination and preventing the falling of water droplets, thereby not affecting agricultural crops.

[0065]

[0066] Example 7 The relationship between the order of addition of raw materials and the amount of ceria sol that can be added was evaluated for the preparation of a coating composition. The composition ratios other than ceria sol were the same as those of Coating Composition B.

[0067] (a) Tetraethoxysilane was condensed in water, ethanol, and hydrochloric acid to prepare a siloxane polymer. An aqueous ceria sol solution and acidic colloidal silica were added to the polymer, in that order. Water was then added to dilute the mixture.

[0068] (b) Tetraethoxysilane was condensed in water, ethanol, and hydrochloric acid to prepare a siloxane polymer. Acidic colloidal silica and an aqueous ceria sol solution were added to the polymer, in that order, and the mixture was diluted with water.

[0069] (c) Tetraethoxysilane, water, ethanol, hydrochloric acid, an aqueous solution of ceria sol, and acidic colloidal silica were reacted simultaneously, and then diluted with water.

[0070] (d) Tetraethoxysilane was condensed in water, ethanol, and hydrochloric acid to prepare a siloxane polymer. Acidic colloidal silica was added to the polymer, which was then diluted with water. An aqueous ceria sol solution was then added to the resulting mixture.

[0071] The amounts of ceria sol that can be added were 30%, 3%, 1%, and 0.5% by solids content for compositions (a) to (d), respectively. Composition (a) can contain more ceria sol than the other compositions, allowing for the amount to be adjusted depending on the application. Furthermore, stable compositions can be produced. If the solids content is higher than the above, the possibility of yellow precipitates forming in the final composition increases, reducing stability.

Claims

1. A method for producing a coating composition, comprising: (A) a step of obtaining an intermediate composition by bringing a polymer obtained by polymerizing silicate alkoxide into the presence of cerium hydroxide and / or cerium oxide; and (B) a step of obtaining a coating composition by bringing the intermediate composition obtained in step (A) into the presence of acidic colloidal silica.

2. The method according to claim 1, further comprising, before step (A), a step of polymerizing the silicate alkoxide to obtain the polymer having a molecular weight of 3 to 40.

3. The method according to claim 1, wherein the silicate alkoxide is tetramethoxysilane and / or tetraethoxysilane.

4. The method according to claim 1, wherein the cerium hydroxide and / or the cerium oxide is a ceria sol having a particle size of 100 nm or less and a cerium concentration of 50% by weight or less in terms of cerium oxide.

5. The manufacturing method according to claim 1, further comprising, after step (B), a step of making the coating composition coexist with a surfactant to obtain a further processed coating composition.

6. The manufacturing method according to claim 1, further comprising, after step (B), a step of obtaining a further processed coating composition by allowing the coating composition or the further processed coating composition to coexist with tin oxide-based microparticles.

7. The manufacturing method according to claim 1, further comprising, after step (B), a step of obtaining a further processed coating composition by causing the coating composition or the further processed coating composition to coexist with an aqueous binder resin component.

8. The production method according to any one of claims 1 to 7, further comprising, after step (B), a step of obtaining a further processed coating composition by causing the coating composition or the further processed coating composition to coexist with a water-soluble solvent and / or water.

9. A coating composition comprising a polymer obtained by polymerizing silicate alkoxide, cerium hydroxide and / or cerium oxide, and acidic colloidal silica.

10. The coating composition according to claim 9, wherein the polymer obtained by polymerizing the silicate alkoxide is a 3-polymer to 40-polymer.

11. The coating composition according to claim 9, wherein the silicate alkoxide is tetramethoxysilane and / or tetraethoxysilane.

12. The coating composition according to claim 9, wherein the cerium hydroxide and / or cerium oxide is a ceria sol having a particle size of 100 nm or less and a cerium concentration of 50% by weight or less calculated as cerium oxide.

13. The coating composition according to claim 9, which has a light transmittance of 80% or more.

14. The coating composition according to claim 9, further comprising a surfactant.

15. The coating composition according to claim 9, further comprising tin oxide-based fine particles.

16. The coating composition according to claim 9, further comprising an aqueous binder resin component.

17. The coating composition according to claim 9, further comprising a water-soluble solvent and / or water.

18. A coated article having a coating layer comprising the coating composition according to any one of claims 10 to 17.

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