Glass article with easy-to-clean coating and method for manufacturing glass article with easy-to-clean coating

Abstract

A coated glass product provided with a glass substrate and an easy-to-clean coating layer on the glass substrate, the easy-to-clean coating layer containing an inorganic substance as a main component, the content of carbon element in the surface of the easy-to-clean coating layer being 8 atm% or more and the content of an alkali metal element being 1.5 atm% or less.

Description

Technical Field

[0001] The invention relates to a glass product with an easy-to-clean coating and a method for manufacturing the glass product with the easy-to-clean coating. Background Art

[0002] A coating called an easy-to-clean coating is formed on the surface of glass and other substrates. This coating imparts easy cleanability, making it easier to remove dirt from the surface. Typically, an easy-to-clean coating is formed by applying a treatment agent containing a fluorine-containing compound or a silicone compound.

[0003] Research is also underway on technologies that impart easy-cleaning properties without relying on organic matter. For example, Patent Document 1 discloses a technology for sintering oxide ceramics by firing them at 1600°C for 5 hours in an atmosphere with low organic and water concentrations. However, this technology imparts easy-cleaning properties to the highly heat-resistant substrate, the oxide ceramic itself, and requires sintering at high temperatures. Therefore, it is difficult to apply to glass substrates. If a glass substrate is heated at 1600°C for 5 hours as disclosed in Patent Document 1, it will generally soften to the point where it can no longer maintain its substrate shape, and in some cases, it will completely melt.

[0004] Existing literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-140277 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] The glass substrate is subjected to a heating treatment at a temperature and for a heating time within a range that does not soften the glass substrate. According to the present inventors' research, the cleanability of an easy-to-clean coating formed on a glass substrate decreases after the heat treatment and then gradually recovers. However, long-term storage before shipment to restore and verify the cleanability significantly reduces manufacturing efficiency. The cleanability of an easy-to-clean coating formed on a glass substrate decreases over extended use. Furthermore, the cleanability varies depending on the location of the glass substrate. Considering manufacturing efficiency and convenience, it is desirable to quickly and repeatedly restore the cleanability of glass products with easy-to-clean coatings while minimizing variations.

[0009] In view of the above, an object of the present invention is to provide a glass product with an easy-to-clean coating suitable for quickly and repeatedly restoring the easy-to-clean property and suppressing variations in the easy-to-clean property, and a method for manufacturing the glass product with the easy-to-clean coating.

[0010] Means of solving the problem

[0011] The present invention provides a coated glass product comprising a glass substrate and an easy-to-clean coating on the glass substrate.

[0012] The easy-to-clean coating contains inorganic matter as a main component,

[0013] The surface of the easy-to-clean coating layer has a carbon content of 8 atm % or more and an alkali metal content of 1.5 atm % or less.

[0014] In another aspect, the present invention provides a method for manufacturing a coated glass product, comprising the following steps:

[0015] A process for forming an easy-to-clean coating containing an inorganic substance as a main component on a glass substrate;

[0016] The process comprises bringing water or steam into contact with the surface of the easy-to-clean coating in an environment in which carbon and oxygen elements exist.

[0017] Effects of the Invention

[0018] According to the present invention, a glass product with an easy-to-clean coating suitable for rapid and repeated restoration of easy-to-clean properties and suppressed variations in easy-to-clean properties, and a method for producing the glass product with an easy-to-clean coating are provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic cross-sectional view for explaining the mechanism by which the cleanability of the coating surface is restored by a water or steam treatment process.

[0020] Figure 2 This is a diagram for explaining the calculation method of the coefficient of dynamic friction in the examples.

[0021] Figure 3 This figure shows the results of observing the glass product produced in Test Example 5 with a scanning electron microscope (SEM) in the state after the coating film is formed (initial state).

[0022] Figure 4 This is a diagram showing the results of SEM observation of the glass product produced in Test Example 5 after heat treatment.

[0023] Figure 5 This is a diagram showing the results of SEM observation of the glass product produced in Test Example 5 after it was subjected to steam treatment (after steam treatment). DETAILED DESCRIPTION

[0024] A coated glass product according to a first aspect of the present invention comprises a glass substrate and an easy-to-clean coating on the glass substrate.

[0025] The easy-to-clean coating contains inorganic matter as a main component,

[0026] The surface of the easy-to-clean coating has a carbon content of 8 atm % or more and an alkali metal content of 1.5 atm % or less.

[0027] In a second aspect of the present invention, for example, in the coated glass product according to the first aspect, the coefficient of dynamic friction of the surface of the easy-to-clean coating layer is 0.50 or less.

[0028] In a third aspect of the present invention, for example, in the coated glass product according to the first or second aspect, the sum of the content of alkali metal elements and the content of alkaline earth metal elements on the surface of the easy-to-clean coating is 10 atm % or less.

[0029] In a fourth aspect of the present invention, for example, in the coated glass product according to any one of the first to third aspects, the inorganic substance contains at least one selected from the group consisting of rare earth element oxides, zirconium oxides, niobium oxides, and tantalum oxides.

[0030] In a fifth aspect of the present invention, for example, in the coated glass product according to the fourth aspect, the oxide of the rare earth element contains at least one selected from the group consisting of cerium oxide, lanthanum oxide, and yttrium oxide.

[0031] In a sixth aspect of the present invention, for example, in the coated glass product according to any one of the first to fifth aspects, the coefficient of dynamic friction of the surface of the easy-to-clean coating after the coated glass product is exposed to a heat treatment at 760° C. for 4 minutes is 0.60 or less.

[0032] In a seventh aspect of the present invention, for example, in the coated glass product according to any one of the first to sixth aspects, the glass substrate is tempered glass.

[0033] In the eighth aspect of the present invention, for example, the coated glass product according to any one of the first to seventh aspects corresponds to at least one type selected from the group consisting of building glass, transportation glass, shop glass, furniture glass, home appliance glass, signage glass, mobile device glass, and solar cell glass.

[0034] In a ninth aspect of the present invention, for example, in the coated glass product according to any one of the first to eighth aspects, the easy-to-clean coating has at least one function selected from the group consisting of anti-glare and anti-fog.

[0035] The method for producing a coated glass product according to a tenth aspect of the present invention comprises the following steps:

[0036] A process for forming an easy-to-clean coating containing an inorganic substance as a main component on a glass substrate;

[0037] The process comprises bringing water or steam into contact with the surface of the easy-to-clean coating in an environment in which carbon and oxygen elements exist.

[0038] In the 11th aspect of the present invention, for example, in the method for producing a coated glass product according to the 10th aspect, the inorganic substance contains at least one selected from the group consisting of oxides of rare earth elements, zirconium oxides, niobium oxides, and tantalum oxides.

[0039] In a twelfth aspect of the present invention, for example, in the method for producing a coated glass product according to the eleventh aspect, the oxide of the rare earth element contains at least one selected from the group consisting of cerium oxide, lanthanum oxide, and yttrium oxide.

[0040] The following description of the embodiments of the present invention is not intended to limit the present invention to a specific embodiment. In this specification, "main component" means a component having a content of 50% or more, particularly 60% or more, calculated on a mass basis. "Substantially free" means a content of less than 1%, further less than 0.1%, calculated on a mass basis. "Substantially flat" means that no concavities or convexities with a height or depth of 500 nm or more are confirmed on the surface when observed with a scanning electron microscope (SEM). "Normal temperature" is used as a term to indicate a temperature in the range of 5 to 35°C, particularly 10 to 30°C.

[0041] [Coated glass products]

[0042] The coated glass product provided in this embodiment (hereinafter referred to as the "glass product") comprises a glass substrate and an easy-to-clean coating (hereinafter referred to as the "coating") on the glass substrate. The coating primarily contains an inorganic substance. The coating surface of the glass product has a carbon content of 8 atm% or greater and an alkali metal content of 1.5 atm% or less.

[0043] The inventors have discovered that a coating containing an inorganic substance as a main component, with a carbon content of 8 atm% or more and an alkali metal content of 1.5 atm% or less on the coating surface, suppresses the increase and deviation of the dynamic friction coefficient on the coating surface, and is suitable for rapid and repeated restoration of cleanability and suppression of deviation in cleanability.

[0044] Hereinafter, the glass substrate and the coating layer constituting the glass product of the present embodiment will be described, followed by a description of uses of the glass product, and finally a description of a method for producing the glass product of the present embodiment.

[0045] (Glass substrate)

[0046] The type of glass that constitutes the glass substrate is not particularly limited. For example, the glass substrate can be composed of various types of glass, such as soda-lime glass, borosilicate glass, aluminosilicate glass, alkali-free glass, low-alkali glass, and quartz glass. These glass substrates may contain SiO2 as a primary component. The glass substrate may also contain oxides of Group 1 elements (alkaline components, alkali metal elements), such as sodium and potassium. The glass substrate may also contain Group 2 elements, such as calcium. The size and shape of the glass substrate are also not particularly limited. The glass substrate may include a glass plate, a glass container, a glass lid, a glass tube, a glass valve, a glass lens, or other formed objects. Glass containers include, for example, glass vials, glass ampoules, and glass bottles, but may also have other shapes, such as trays and petri dishes. The shape of the glass lid is not limited as long as it functions as a lid; for example, it may have a shape suitable for use as a lid for cooking utensils.

[0047] As mentioned above, the glass substrate may be a glass plate. The glass plate may be flat, but may also have a curved shape imparted by a bending process. The thickness of the glass plate is not particularly limited, and may be, for example, within a range of 0.5 mm to 12 mm. The glass plate may also be treated in a manner suitable for use as window glass for buildings, vehicles, etc. A strengthening treatment, for example, may also be applied to the glass plate. In other words, the glass substrate of the glass plate may be a strengthened glass. Known strengthening treatments include: air-cooling strengthening, which is heating followed by rapid cooling to produce a compressive stress layer on the surface; and chemical strengthening, which is ion exchange of alkali metal ions to produce a compressive stress layer on the surface. The glass plate may also be integrated with other glass plates by laminating and / or hollowing.

[0048] In the above-mentioned processing of glass sheets, the glass sheets are often heated. For example, the bending process of glass sheets includes the process of heating the glass sheets to soften them. In addition to the strengthening process, the glass sheets are sometimes heated to high temperatures during the interlayer processing and hollow processing, depending on the type of resin film sandwiched between the glass sheets or the type of sealing material used to seal the space between the glass sheets. In order to prevent the easy-to-clean coating from being reduced in cleanability due to these heating processes, it is also considered to form the coating after the heating process of the glass sheets. However, this process limitation will hinder the efficiency of mass production. For example, the difficulty of uniformly applying a coating liquid on a curved surface is particularly different from that of applying it on the surface of a flat plate. The process of applying a coating liquid on a flat ribbon of glass before being cut and processed to have a curved surface can be carried out extremely efficiently.

[0049] The problem of reduced cleanability associated with heating is not limited to glass sheets, but occurs throughout the entire glass substrate. In contrast, according to this embodiment, since cleanability is achieved independently of organic matter, the reduction in cleanability associated with heating can be suppressed. Therefore, the method of this embodiment enables various treatments to be performed on the coated glass substrate by heating the coated glass substrate after coating.

[0050] Examples of various treatments involving heating include, for example, at least one selected from the group consisting of bending treatment involving heating (heat bending treatment), air-cooling tempering treatment, chemical strengthening treatment, lamination treatment, hollowing treatment, and coating treatment, particularly heat bending treatment and / or air-cooling tempering treatment. In other words, in this embodiment, the glass substrate may be a glass sheet that has been subjected to at least one treatment selected from the group consisting of heat bending treatment and air-cooling tempering treatment. The temperature suitable for these heat treatments is generally up to approximately 760°C.

[0051] Conventionally, after a glass sheet is cut into a predetermined shape, it is subjected to a heat bending process and / or air-cooling tempering treatment, after which a coating liquid for forming an easy-to-clean coating is applied to the main surfaces of the glass sheet. Consequently, a portion of the coating liquid adheres to the end surfaces of the glass sheet, forming a coating on at least a portion of the end surfaces. In contrast, according to this embodiment, a coating liquid can be applied to one main surface of a flat glass sheet to form an easy-to-clean coating, and the glass sheet can then be subjected to at least one treatment selected from the group consisting of heat bending and air-cooling tempering. This method provides a glass sheet with a coating on at least one main surface while leaving the end surfaces uncoated. Conventional methods tend to result in locally thicker coatings on the end surfaces, where the coating liquid tends to pool. This avoids this problem, which is advantageous in terms of ensuring the aesthetics of the product. This not only improves quality, but also helps reduce the cost of the final product by allowing continuous coating of a large area of ​​the glass sheet before cutting.

[0052] (coating)

[0053] In this embodiment, the carbon content of the easy-to-clean coating surface is 8 atm% or more and the alkali metal content is 1.5 atm% or less. In a glass product having such a structure, the increase and variation of the dynamic friction coefficient of the coating surface are suppressed.

[0054] In this embodiment, the easy-to-clean coating contains an inorganic substance as a main component. A coating containing an inorganic substance as a main component is suitable for the case where a heat treatment at a high temperature is performed. The coating may be substantially free of organic matter. As inorganic substances, various inorganic compounds such as oxides, nitrides, and carbides can be listed, preferably oxides. The coating may contain an oxide as a main component. Preferred oxides include oxides of rare earth elements, zirconium oxides, niobium oxides, and tantalum oxides. These oxides are suitable for the manifestation of appropriate easy-to-clean properties. The oxide may contain at least one selected from the group consisting of oxides of rare earth elements, zirconium oxides, niobium oxides, and tantalum oxides.

[0055] A particularly preferred oxide is zirconium oxide. The coating may contain zirconium oxide. The coating may contain zirconium oxide in an amount of 5 mol% or greater, 8 mol% or greater, or 9 mol% or greater. The upper limit of the zirconium oxide content is not particularly limited, but is preferably 90 mol%. If the zirconium oxide content exceeds 90 mol%, the adhesion between the glass substrate and the coating tends to decrease. The coating may contain zirconium oxide as a main component. The coating may be a film that is substantially free of components other than zirconium oxide.

[0056] The coating layer may contain an oxide of a rare earth element. The oxide of a rare earth element may include at least one selected from the group consisting of cerium oxide, lanthanum oxide, and yttrium oxide.

[0057] The oxide of a rare earth element can be cerium oxide. Like zirconium oxide, cerium oxide is a preferred material for imparting suitable easy-to-clean properties. Cerium oxide can be crystalline. Crystalline rare earth oxides, particularly cerium oxide, are suitable for exhibiting easy-to-clean properties. The crystallite size of crystalline cerium oxide is, for example, in the range of 4 to 10 nm. When crystals develop to such a small size, even with a thin coating, the diffusion distance from the glass substrate is increased, making it difficult for alkaline components (alkali metal elements) to reach the coating surface, thereby suppressing a decrease in easy-to-clean properties.

[0058] According to studies conducted by the present inventors using X-ray diffraction, the combination of zirconium oxide and cerium oxide is particularly suitable for use in easy-to-clean coatings because zirconium oxide does not impair the crystallinity of cerium oxide but can cooperate with cerium oxide.

[0059] The coating may contain cerium oxide in an amount of 10 mol %, 30 mol %, 40 mol %, or even 50 mol %. The upper limit of the cerium oxide content is not particularly limited, but is preferably 95 mol %. If the cerium oxide content exceeds 95 mol %, the adhesion between the glass substrate and the coating tends to decrease. The coating may contain cerium oxide as a main component. The coating may be a film that is substantially free of components other than cerium oxide, or a film that is substantially free of components other than cerium oxide and zirconium oxide. The cerium oxide preferably contains CeO2, i.e., tetravalent cerium oxide. From the perspective of improving easy cleaning, CeO2 is a more preferred component than Ce2O3, i.e., trivalent cerium oxide. However, the coating may also contain Ce2O3 as cerium oxide. For example, when a compound containing trivalent cerium is used as a source of cerium oxide and a portion of it is oxidized to tetravalent cerium, the remaining trivalent cerium is contained in the coating as Ce2O3 together with CeO2. In this specification, all cerium oxides are converted into CeO 2 . In other words, the cerium oxide content and other ratios or proportions in the coating layer are calculated assuming that all cerium exists in a tetravalent state.

[0060] In the easy-to-clean coating, the molar ratio of cerium oxide to zirconium oxide (cerium oxide / zirconium oxide) is not particularly limited and may be 0.01 or more, 0.1 or more, 0.5 or more, 0.75 or more, or 1 or more, and may be 50 or less, 30 or less, 20 or less, or 15 or less.

[0061] The coating may contain zirconium oxide and / or rare earth element oxides, as well as aluminum oxide. Aluminum oxide can contribute to improved cleanability of the coating. The coating may contain aluminum oxide in an amount of 5 mol% or greater, 10 mol% or greater, or even 20 mol% or greater. The upper limit of the aluminum oxide content is not particularly limited, but is preferably 50 mol%. If the aluminum oxide content exceeds 50 mol%, the cleanability of the coating tends to decrease.

[0062] The content of alkali metal elements on the coating surface may be 0.1 atm% or more and 1.5 atm% or less. The lower limit of the content of alkali metal elements on the coating surface may be 0.2 atm% or 0.3 atm%.

[0063] The carbon content of the coating surface may be greater than or equal to 2 atm% and less than or equal to 60 atm%. The lower limit of the carbon content of the coating surface may be 10 atm%, or 20 atm%. The upper limit of the carbon content of the coating surface may be 50 atm%, or 40 atm%.

[0064] In this embodiment, the sum of the content of alkali metal elements and the content of alkaline earth metal elements on the coating surface is preferably 10 atm% or less. The sum of the content of alkali metal elements and the content of alkaline earth metal elements on the coating surface may be 8 atm% or less, or 6 atm% or less.

[0065] A representative example of an alkali metal element is sodium. A representative example of an alkaline earth metal element is calcium. However, combinations of alkali metal elements and alkaline earth metal elements may include sodium and magnesium, sodium and strontium, potassium and calcium, lithium and calcium, lithium and magnesium, and the like.

[0066] The lower limit of the sum of the content of alkali metal elements and alkaline earth metal elements on the coating surface is not particularly limited, but may be 0.1 atm %, 0.5 atm %, or even 1 atm %.

[0067] The sum of the contents of Group 1 elements and Group 2 elements on the glass substrate-side surface of the coating layer is preferably limited. This sum can be 5 atm% or less, 4 atm% or less, 3 atm% or less, or even 2 atm% or less. However, the sum of the contents of Group 1 elements and Group 2 elements in the glass composition constituting the glass substrate can exceed 5 atm%, and can be 7 atm% or more, or even 10 atm% or more. Furthermore, while the components that affect coating properties are primarily Group 1 elements, Group 2 elements can also have some influence.

[0068] In this embodiment, the kinetic friction coefficient of the coating surface can be 0.50 or less. The kinetic friction coefficient is the ratio (F / W) of the friction force F acting on the contact surface to the vertical resistance W acting perpendicular to the contact surface when two objects are in contact and moving. The present inventors have discovered that the kinetic friction coefficient, which is related to surface roughness, is suitable as an evaluation indicator for the cleanability of coating surfaces primarily composed of inorganic substances. Glass products with a kinetic friction coefficient on the coating surface within the above range have excellent cleanability. Specifically, glass products with a kinetic friction coefficient on the coating surface within the above range can easily wash away dirt and / or foreign matter attached to the coating surface by spraying water. In the past, while spraying water could reduce dirt and / or foreign matter attached to the coating surface to a certain extent, some areas of the coating surface still had residual dirt and / or foreign matter. One reason for this is believed to be that heat treatment of the glass substrate creates areas where alkaline components (alkali metal elements) such as Na diffuse unevenly. High concentrations of alkali metal elements (particularly Na) increase the coefficient of kinetic friction, causing variations in the absolute value of the coefficient of kinetic friction. This results in residual stains on the coating surface, deteriorating its appearance. Research by the present inventors has shown that reducing the coefficient of kinetic friction itself inevitably reduces its variations, reducing stains and improving appearance. The coefficient of kinetic friction on the coating surface can be 0.45 or less, 0.40 or less, 0.35 or less, or even 0.30 or less.

[0069] The lower limit of the coefficient of kinetic friction of the coating surface is not particularly limited. The lower limit of the coefficient of kinetic friction may be, for example, 0.05, 0.08, or even 0.09.

[0070] In this embodiment, the coefficient of kinetic friction of the coating surface can have a deviation of ±0.10 (dimensionless number). Thus, in the glass product of this embodiment, the variation in the cleanability of the coating surface is suppressed. Glass products with suppressed variation in cleanability are less likely to retain stains on the coating surface.

[0071] In this embodiment, the kinetic friction coefficient of the coating surface after the glass article is exposed to a heat treatment at 760°C for 4 minutes can be 0.60 or less. Furthermore, in this embodiment, the kinetic friction coefficient of the coating surface may temporarily increase after the heat treatment, depending on the coating composition. Therefore, it can be measured again after a certain period of time. Recovery of the kinetic friction coefficient may take several dozen days. Therefore, the kinetic friction coefficient can be measured, for example, by exposing the glass article to a heat treatment at 760°C for 4 minutes and then storing it in ambient air for 4 weeks.

[0072] The lower limit of the dynamic friction coefficient of the coating surface after exposure to heat treatment is not particularly limited. The lower limit of the dynamic friction coefficient may be, for example, 0.05, 0.08, or even 0.09.

[0073] In this embodiment, the coating layer may contain substantially no fluorine-containing organic compounds, particularly no fluorinated alkyl-containing compounds.

[0074] The easy-to-clean coating layer of this embodiment may be a single-layer film.

[0075] Easy-to-clean coatings on substrates such as glass typically have a multilayer structure comprising a metal oxide layer providing a base and a topcoat layer of an organic compound. To ensure a strong bond with the metal oxide layer, which functions as an adhesive layer, the topcoat layer is often composed of a hydrolyzed polycondensate of a hydrolyzable organosilicon compound. Hydrolyzable organosilicon compounds are organic compounds suitable for improving easy cleaning, typically containing fluoroalkyl groups. In contrast, in this embodiment, the coating may be substantially free of hydrolyzed polycondensates of hydrolyzable organosilicon compounds. Alternatively, the coating may be substantially free of fluorinated organic compounds, particularly, substantially free of fluoroalkyl groups.

[0076] The coating of this embodiment can be a single-layer film or a multilayer film. A single-layer film is advantageous in reducing mass production costs. Even a single-layer film can provide easy cleaning. In the case of a multilayer film, the coating preferably includes a layer containing zirconium oxide as the topmost layer of the multilayer film.

[0077] In other words, in this embodiment, a base layer may be further included between the glass substrate and the coating layer. The inclusion of the base layer suppresses the diffusion and migration of alkaline components of the glass from the glass substrate to the coating layer. The base layer may be, for example, a metal oxide layer. Specifically, it may be a layer having a lower zirconium oxide content than the surface layer by mass standard, and substantially no zirconium oxide. The base layer may contain at least one selected from the group consisting of silicon oxide and aluminum oxide. A preferred example of a base layer is a layer containing silicon oxide as a main component. The base layer itself may also be multilayered.

[0078] The base layer can be amorphous. Because the easy-to-clean coating is crystalline, alkaline components (alkali metals) easily diffuse from the glass substrate into the coating. However, an amorphous base layer lacks grain boundaries, further suppressing the diffusion of alkali metals from the glass substrate into the coating.

[0079] The thickness of the base layer is, for example, in the range of 10 to 400 nm. The thickness of the base layer may be 10 nm or more, 20 nm or more, or 30 nm or more, or 350 nm or less, 300 nm or less, or 250 nm or less.

[0080] The base layer may be a layer capable of functioning as a low-emissivity film (Low-E film), a conductive film, a reflection-reducing film, a colored film, or the like.

[0081] A Low-E film, for example, is a laminated film including a conductive layer. For example, a Low-E film has a laminated structure in which a color adjustment layer and a conductive layer are laminated in order from the main surface side of a glass substrate. The color adjustment layer is a layer having at least one oxide selected as a main component from, for example, silicon, aluminum, zinc, and tin. The color adjustment layer can be a layer having tin oxide as a main component. The thickness of the color adjustment layer is, for example, greater than 25 nm and less than 90 nm, particularly greater than 35 nm and less than 70 nm. The color adjustment layer can be composed of two or more layers having different refractive indices. For example, the two layers having different refractive indices are, starting from the glass substrate side of a glass plate, a first color adjustment layer having tin oxide as a main component and a second color adjustment layer having silicon oxide as a main component. However, the lamination order of the first color adjustment layer and the second color adjustment layer is not particularly limited. The conductive layer is a layer primarily composed of at least one of indium tin oxide (ITO), zinc aluminum oxide, antimony-doped tin oxide (SnO2:Sb), and fluorine-doped tin oxide (SnO2:F). The conductive layer may be a layer primarily composed of fluorine-doped tin oxide (SnO2:F). The thickness of the conductive layer is, for example, 100 nm to 350 nm, particularly 120 nm to 260 nm.

[0082] The thickness of the easy-to-clean coating is, for example, 2 nm to 1000 nm, further 5 nm to 500 nm, and particularly 10 nm to 300 nm. The coating may have a thickness of 15 nm to 20 nm, or 100 nm to 50 nm, or 50 nm to 50 nm. Excessively thick easy-to-clean coatings are prone to cracking, which can cause peeling. Therefore, the coating preferably has a thickness of 30 nm or less.

[0083] The surface of the easy-to-clean coating may be substantially flat.

[0084] Furthermore, when the glass substrate is a glass plate, the coating layer may be formed on only one main surface of the glass plate or on both main surfaces of the glass plate. However, in order to prevent a decrease in visible light transmittance, it is preferred to form the coating layer on only one main surface of the glass plate.

[0085] The glass product of this embodiment can be understood as comprising a cleanability-enhancing layer on the surface of the easy-to-clean coating. That is, the glass product may further comprise a cleanability-enhancing layer on the surface of the coating. The surface of the cleanability-enhancing layer may have a carbon content of 8 atm% or greater, and an alkali metal content of 1.5 atm% or less.

[0086] In this embodiment, the so-called easy-to-clean layer refers to a new layer formed on the surface of the coating by bringing water or steam into contact with the surface in an environment with carbon and oxygen elements (for example, in air). According to research by the present inventors, bringing water or steam into contact with the surface of the coating in an environment with carbon and oxygen elements results in the formation of a new layer, thereby rapidly restoring the easy-to-clean properties of the coating surface. Based on the results of elemental analysis described later, it is believed that this new layer (the easy-to-clean layer) blocks the diffusion of glass components, particularly alkaline components, from the glass substrate into the coating, thereby contributing to improved easy-to-clean properties of the coating surface. If the easy-to-clean property decreases due to heat treatment or long-term use, the easy-to-clean layer is formed by bringing water or steam into contact with the surface of the coating in an environment with carbon and oxygen elements. In this way, the easy-to-clean property of the coating surface is repeatedly restored.

[0087] The easy-to-clean layer contains carbon and oxygen. The easy-to-clean layer may also contain carbon as a main component.

[0088] The easy-to-clean layer may include organic matter containing carbon and oxygen. The easy-to-clean layer may also be formed by adsorbing organic matter containing carbon and oxygen on the surface of the coating.

[0089] The carbon content on the surface of the easy-to-clean layer may be greater than or equal to 2 atm% and less than or equal to 60 atm%. The lower limit of the carbon content on the surface of the easy-to-clean layer may be 10 atm%, or 20 atm%. The upper limit of the carbon content on the surface of the easy-to-clean layer may be 50 atm%, or 40 atm%.

[0090] The oxygen content on the surface of the easy-to-clean layer may be greater than or equal to 10 atm% and less than or equal to 80 atm%. The lower limit of the oxygen content on the surface of the easy-to-clean layer may be 20 atm%, or 30 atm%. The upper limit of the oxygen content on the surface of the easy-to-clean layer may be 70 atm%, or 65 atm%.

[0091] The content of alkali metal elements on the surface of the easy-to-clean layer may be 0.1 atm% to 1.5 atm%. The lower limit of the content of alkali metal elements on the surface of the easy-to-clean layer may be 0.2 atm% or 0.3 atm%.

[0092] The sum of the alkali metal content and the alkaline earth metal content on the surface of the easy-to-clean layer may be 10 atm% or less. The sum of the alkali metal content and the alkaline earth metal content on the surface of the easy-to-clean layer may also be 8 atm% or less, or 6 atm% or less.

[0093] The lower limit of the sum of the content of alkali metal elements and alkaline earth metal elements on the surface of the easy-to-clean layer is not particularly limited, but may be 0.1 atm %, 0.5 atm %, or even 1 atm %.

[0094] The kinetic friction coefficient of the surface of the easy-to-clean layer may be 0.50 or less. The kinetic friction coefficient of the surface of the easy-to-clean layer may also be 0.45 or less, 0.40 or less, 0.35 or less, or further 0.30 or less.

[0095] The lower limit of the dynamic friction coefficient of the surface of the easy-to-clean layer is not particularly limited. The lower limit of the dynamic friction coefficient may be, for example, 0.05, 0.08, or even 0.09.

[0096] The deviation of the dynamic friction coefficient of the surface of the easy-cleaning improving layer may be ±0.10 (dimensionless number).

[0097] After the glass article is exposed to a heat treatment at 760°C for 4 minutes, the kinetic friction coefficient of the surface of the easy-to-clean layer can be 0.60 or less. The kinetic friction coefficient of the surface of the easy-to-clean layer after exposure to the heat treatment can also be 0.40 or less, 0.30 or less, 0.25 or less, or even 0.20 or less. The kinetic friction coefficient can be measured, for example, after the glass article is exposed to a heat treatment at 760°C for 4 minutes and then stored in ambient air for 4 weeks.

[0098] The lower limit of the dynamic friction coefficient of the surface of the easy-to-clean layer after exposure to the heat treatment is not particularly limited. The lower limit of the dynamic friction coefficient may be, for example, 0.05, 0.08, or even 0.09.

[0099] The thickness of the easy-to-clean layer is, for example, in the range of 10 to 400 nm. The thickness of the easy-to-clean layer may be 10 nm or more, 20 nm or more, or 30 nm or more, or 350 nm or less, 300 nm or less, or 250 nm or less.

[0100] The surface of the easy-cleaning improving layer may be substantially flat.

[0101] (Uses of glass products)

[0102] The glass product of this embodiment can be used in a variety of applications, but is particularly suitable for use in environments subject to water droplets. Water droplets are typically provided by natural water such as rain and fog, or by tap water. Specifically, the glass product of this embodiment can be at least one article selected from the group consisting of building glass, vehicle glass, store glass, furniture glass, appliance glass, signage glass, mobile device glass, and solar cell glass. The glass product of this embodiment can also be at least one article selected from the group consisting of window glass, roof glass, bathroom glass, mirror, store glass, mobile device glass, and solar cell glass. Window glass is, for example, the window glass of a building or vehicle, as is roof glass. Buildings are not limited to houses and buildings, but also include greenhouses, arcades, and other structures fixed to the ground. Vehicles include vehicles, ships, and aircraft. Vehicles include, for example, automobiles and railway vehicles. Bathroom glass includes, for example, bathroom glass partitions and doors. Mirrors include, for example, bathroom mirrors and vanity mirrors. Examples of store glass include display windows, counters, tables, refrigerator and freezer glass doors, and food display cases. Mobile device glass includes the glass covering the display of mobile devices like smartphones and tablet PCs, and in some cases, the glass forming the mobile device's housing. Solar cell glass includes, for example, the cover glass placed on the light-incident side of a solar cell. Tempered glass is often used in these applications, particularly when ensuring human safety is crucial.

[0103] In the above applications, the easy-to-clean coating of this embodiment can not only provide easy cleaning but also other functions such as anti-glare and anti-fog. The easy-to-clean coating of this embodiment can have at least one function selected from the group consisting of anti-glare and anti-fog.

[0104] [Method for manufacturing coated glass products]

[0105] Next, a method for producing the glass product of the present embodiment will be described. However, the glass product of the present embodiment may be produced by methods other than the following production method.

[0106] The manufacturing method of this embodiment includes the following steps: a step of forming an easy-to-clean coating containing an inorganic substance as a main component on a glass substrate (coating formation step); and a step of bringing water or steam into contact with the surface of the easy-to-clean coating in an environment in which carbon and oxygen elements are present (water or steam treatment step).

[0107] According to the inventors' research, when water or steam comes into contact with the surface of a coating in an environment containing carbon and oxygen, a new layer forms on the coating surface, rapidly and repeatedly restoring the coating's surface cleanability. Based on the results of elemental analysis described below, it is believed that this new layer blocks the diffusion of glass components, particularly alkaline components, from the glass substrate into the coating, thereby contributing to improved surface cleanability.

[0108] (Water or steam treatment process)

[0109] In the water or steam treatment step, the method for bringing water or steam into contact with the surface of the coating in an environment containing carbon and oxygen elements is not particularly limited. For example, moisture at a temperature of 100°C or below can be brought into contact with the surface of the coating in a high-temperature, high-humidity tank. More specifically, the coated glass substrate can be stored in a high-temperature, high-humidity tank maintained at 80°C and 80% humidity for 10 minutes. For example, superheated steam can be sprayed onto the surface of the coating in air. In other words, the surface of the coating can be subjected to a water vapor treatment.

[0110] Regarding the mechanism of restoring the cleanability of the coating surface by water or steam treatment, refer to Figure 1 illustrate. Figure 1 The glass product 10 shown includes a glass substrate 1 and a coating 2 on the glass substrate 1. Reference numeral 50 indicates a water droplet on the coating 2. Figure 1 (A) shows the glass product 10 in a state where the easy-cleaning property of the coating layer 2 is exhibited. Figure 1 (B) shows the glass product 10 in a state where the cleanability of the coating layer 2 has been reduced due to heat treatment, for example. Figure 1 (C) means that for example Figure 1 The glass product 10 in state (B) is in a state where the surface of the coating layer 2 is subjected to a steam treatment to generate a new layer 3 .

[0111] like Figure 1 As shown in (A), the glass product 10 has high cleanability due to the coating 2. The dynamic friction coefficient of the coating surface is, for example, 0.50 or less. Figure 1 As shown in (B), the cleanability of the coating 2 decreases after heat treatment and long-term use. This is believed to be due to the diffusion of glass components, especially alkaline components (alkali metal elements), from the glass substrate 1 to the coating 2.

[0112] In the manufacturing method of this embodiment, the water or steam treatment step is performed. Figure 1 The surface of the coating 2 of the glass article 10 in the state (B) causes a new layer 3 to form. Under the action of the new layer 3, as Figure 1As shown in (C), the easy-to-clean property of the surface of the coating 2 can be quickly restored. The new layer 3 can also be considered as a layer that improves the easy-to-clean property. In other words, the water or steam treatment step can also be understood as a step that generates a layer that improves the easy-to-clean property on the surface of the coating.

[0113] While the details of the reason are unclear, it is believed that when water or steam comes into contact with the surface of coating 2 in an environment where carbon and oxygen elements are present, alkaline components (alkali metal elements) that diffuse from glass substrate 1 into coating 2 are washed away. Furthermore, organic matter containing carbon and oxygen elements is adsorbed onto the surface of coating 2, forming a new layer (easy-to-clean layer) 3. This new layer 3 is believed to block the diffusion of alkaline components from the glass substrate into coating 2, resulting in the restoration of the easy-to-clean surface of coating 2.

[0114] In the water or steam treatment step, when the method of water vapor treatment is to contact water or steam with the surface of the coating in an environment in which carbon and oxygen elements are present, the water vapor treatment is performed, for example, in air at a water temperature of 50°C to 100°C for 5 to 60 seconds. For example, the water vapor treatment can be performed by spraying 90°C water vapor on the coating surface of the glass article in air for 60 seconds, or by spraying 250°C superheated steam on the coating surface of the glass article in air for 10 seconds.

[0115] In the glass product produced by the production method of this embodiment, the carbon content on the coating surface is 8 atm % or more and the alkali metal content is 1.5 atm % or less.

[0116] In the glass product manufactured by the method for manufacturing a glass product according to the present embodiment, the coefficient of dynamic friction of the coating surface may be 0.50 or less.

[0117] In glass products manufactured using the method for manufacturing glass products according to this embodiment, the coefficient of kinetic friction on the coating surface can have a variation of ±0.10 (dimensionless number). On the other hand, in glass products manufactured without water or steam treatment, the coefficient of kinetic friction on the coating surface has a variation of ±0.20 (dimensionless number). Glass products with a coefficient of kinetic friction variation within this range are less likely to retain stains on the coating surface.

[0118] If the glass product manufactured by the glass product manufacturing method of this embodiment is exposed to heat treatment, the coating's cleanability will decrease again. That is, the coating's surface dynamic friction coefficient will increase again. For example, after the glass product is exposed to a heat treatment at 760°C for 4 minutes, the coating's surface dynamic friction coefficient will be below 0.60. If the coating's cleanability decreases again, a new layer (cleanability-enhancing layer) can be generated on the coating's surface by performing the water or steam treatment step again. In other words, the coating's surface cleanability can be repeatedly restored. Thus, in the glass product manufacturing method of this embodiment, the water or steam treatment step can be performed multiple times.

[0119] If the coating's cleanability decreases again, it's preferable to perform a process to calcine the coating surface (coating calcine process) before the water or steam treatment process. This calcine process can make the coating surface uniform, allowing a new layer (cleanability-enhancing layer) to form more uniformly during the water or steam treatment process. The coating calcine process is performed, for example, at a temperature of 550°C to 700°C for 180 to 600 seconds.

[0120] (Coating formation process)

[0121] In the coating forming step, the method for forming the coating on the glass substrate is not particularly limited. For example, a coating liquid containing an inorganic substance as a main component can be applied to the glass substrate to form a coating film on the glass substrate. Preferably, a drying step is performed after the coating film is formed.

[0122] The inorganic substance includes at least one oxide selected from the group consisting of rare earth element oxides, zirconium oxides, niobium oxides, and tantalum oxides. The rare earth element oxide includes at least one oxide selected from the group consisting of cerium oxide, lanthanum oxide, and yttrium oxide. Furthermore, the oxide as a solid component does not need to be a complete oxide as long as it can provide the coating. For example, when the oxide is zirconium oxide, the solid oxide may also include zirconate hydroxide and zirconium hydroxide, which can provide zirconium oxide after dehydration condensation.

[0123] The coating formation step may include a step of preparing a coating liquid. The coating liquid may contain a polar solvent, particularly a lower alcohol having 5 or fewer carbon atoms as a solvent. The lower alcohol may be methanol and / or ethanol. The step of preparing the coating liquid may include dissolving the zirconium compound in a polar solvent. Therefore, the zirconium compound may be a compound soluble in a polar solvent.

[0124] The prepared coating liquid is applied to the glass substrate. The coating liquid can be applied by a known method such as spin coating, bar coating, spray coating, nozzle flow coating, or roller coating.

[0125] The coating layer forming step may further include performing at least one treatment selected from cleaning and drying the coating film.

[0126] When the coating liquid contains zirconium oxide and a rare earth element oxide, such as cerium oxide, the production method of this embodiment includes the following steps: applying the coating liquid containing zirconium oxide and cerium oxide to a glass substrate to form a coating film on the glass substrate; and drying the coating film. Cerium oxide includes CeO2. Furthermore, the cerium oxide does not need to be a complete oxide, as long as it is a component capable of providing cerium oxide to the coating. It also includes ceric acid hydroxide and cerium hydroxide, which can provide cerium oxide after dehydration and condensation.

[0127] In this case, the step of preparing the coating liquid may further include hydrolyzing a cerium compound containing trivalent cerium. The hydrolyzable cerium compound is preferably one that dissolves in a polar solvent, specifically, water-soluble cerium compounds. The cerium compound may be, for example, at least one selected from the group consisting of cerium halides and cerium nitrates. Examples of cerium halides include cerium (III) chloride and cerium (III) bromide. For cerium (III) nitrate, as exemplified herein, the preferred cerium compound is a trivalent cerium compound. However, this is not limiting; the cerium compound may also include tetravalent cerium. Oxidation of trivalent cerium to tetravalent cerium takes time. Therefore, when the coating liquid contains zirconium oxide and cerium oxide, the production method of this embodiment may further include a step of maintaining at least one of the coating liquid and the wet coating film for a predetermined time. This step can be carried out, for example, by maintaining at least one of the prepared coating liquid and the wet coating film at a temperature of 5 to 80°C for 0.5 to 48 hours. Through this process, the coating liquid or coating film is similar to being "aged," and the ratio of tetravalent cerium increases. The coating liquid is preferably the subject of aging. For example, as the conversion to tetravalent cerium progresses, coloration due to the tetravalent cerium is observed in the coating liquid. A coating liquid containing only trivalent cerium is colorless unless other coloring materials are included. As tetravalent cerium is generated, the coating liquid typically first becomes brown and then further yellow. During the maintenance period, in order to generate a sufficient amount of tetravalent cerium, the pH of the coating liquid is preferably maintained at a level that is not too low.

[0128] The formation of tetravalent cerium can be monitored through absorption spectroscopy from the ultraviolet region to the visible region. For example, the coating liquid's absorption peak in the ultraviolet region shifts toward longer wavelengths as tetravalent cerium is generated. If this absorption peak continues to age, for example, until it reaches wavelengths above 350 nm, particularly above 360 ​​nm, sufficient tetravalent cerium has been generated to create an easy-to-clean coating.

[0129] The coating formation step can also be implemented as a method comprising the following steps: applying a coating liquid containing chelated zirconium ions onto a glass substrate to form a coating film on the glass substrate; and drying the coating film. To chelate the zirconium ions, a common chelating agent such as EDTA or acetylacetone can be used without particular limitation.

[0130] When the coating liquid contains zirconium oxide and cerium oxide, the coating formation step can also be implemented as a method comprising the following steps: applying the coating liquid containing chelated zirconium ions and chelated cerium ions to a glass substrate to form a coating film on the glass substrate; and drying the coating film. Common chelating agents such as EDTA and acetylacetone can be used for chelation without particular limitation. The cerium ions in the coating liquid can be trivalent cerium. Chelated trivalent cerium ions are easily at least partially oxidized to tetravalent cerium during the drying step after application of the coating liquid, and further during the heat treatment step.

[0131] The coating formation process is not limited to the above-mentioned liquid phase film formation method. For example, the coating may be formed on the glass substrate by CVD (chemical vapor deposition) or PVD (physical vapor deposition).

[0132] The manufacturing method of this embodiment may further include subjecting the glass substrate to a treatment involving heating after the coating formation step and before the water or steam treatment step. The treatment involving heating is at least one selected from the group consisting of the above examples, particularly a heat bending treatment and / or an air cooling tempering treatment. Of course, the glass substrate of this embodiment may be used without such treatment.

[0133] Example

[0134] The present invention will be described in more detail below using examples. However, the following examples are not intended to limit the present invention to any specific embodiment. In these examples, all coated glass products comprising a glass substrate and an easy-to-clean coating on the glass substrate are referred to as "glass products." Therefore, in these examples, glass products that do not have the configuration of the present invention, that is, do not meet the requirements of "a carbon content of 8 atm% or greater and an alkali metal content of 1.5 atm% or less on the surface of the easy-to-clean coating," are also referred to as "glass products."

[0135] (Heat Treatment)

[0136] The heat treatment was carried out by heating the glass article in an electric furnace set at 760°C for 4 minutes, removing it from the furnace, wrapping it with ceramic wool, and cooling it to room temperature at a cooling rate that did not cause thermal cracking.

[0137] (Steam treatment)

[0138] The water vapor treatment was performed by spraying water vapor at 90° C. for 60 seconds on the surface of the coating layer of the glass article in air.

[0139] (dynamic friction coefficient)

[0140] The dynamic friction coefficient was measured using the following method. Measurements were made using an automated friction and wear analyzer (TSf-503, Bowden type) manufactured by Kyowa Interface Science Co., Ltd. A 40 cm square glass sample was used as the measurement sample. A counter-abrasive ball (steel ball) was brought into contact with the coating-side surface of the sample under a small load (vertical resistance W = 200 g). The friction force F was measured while the stage holding the sample was moved a distance of 50 cm at a speed of 10 mm / sec. Figure 2 This is a diagram used to explain the calculation method of the coefficient of kinetic friction. Figure 2 As shown, the friction force F was measured at five points A to E on the coating side of the glass article. The dynamic friction coefficient was calculated using the formula F / W. The average of the dynamic friction coefficients calculated at the five points was considered the dynamic friction coefficient of the coating surface.

[0141] (Elemental Analysis)

[0142] X-ray photoelectron spectroscopy (XPS) was used to analyze the depth distribution of each element shown in Tables 2 and 3 for each glass substrate. Analysis was performed using a scanning electron microscope (Nova NanoSEM 450, manufactured by FEI, USA). The X-ray beam spot diameter was 10 nm.

[0143] <Test Example 1>

[0144] A coating solution was prepared by dissolving 3.33g of cerium (III) nitrate hexahydrate (Ce(NO₃)₃·6H₂O) (98% by Fujifilm Wako Pure Chemical Industries, Ltd.), 2.48g of diacetoxyzirconium (IV) oxide (C₄H₆O₅Zr) (20% by Tokyo Chemical Industry Co., Ltd.), 67.2g of acetylacetone, and 60g of propylene glycol in 267.0g of an ethanol-based mixed solvent (Fineeter A-10 by Futaba Chemicals Co., Ltd.). The molar ratio of CeO₂ to ZrO₂ in the coating solution was 3.5:1. The coating solution was then aged at 40°C for at least 15 hours with continuous stirring. The aged coating solution exhibited a light yellow color.

[0145] As the glass substrate, a high-transmittance glass (Optiwhite (registered trademark), 3 mm thick, manufactured by Nippon Sheet Glass Co., Ltd., hereinafter referred to as "OPW") was used. This glass plate was cut into 40 cm squares, cleaned, and dried. The aged coating solution was sprayed onto the glass plate. The coated glass product was then subjected to the aforementioned drying process. The glass product obtained in this manner was designated as the glass product of Test Example 1.

[0146] <Test Example 2>

[0147] A coating solution was prepared by dissolving 3.33g of cerium (III) nitrate hexahydrate (Ce(NO₃)₃·6H₂O) (98% by Fujifilm Wako Pure Chemical Industries, Ltd.), 0.53g of aluminum nitrate nonahydrate (Al(NO₃)₃·9H₂O) (20% by Tokyo Chemical Industry Co., Ltd.), 67.2g of acetylacetone, and 60g of propylene glycol in 269.5g of an ethanol-based mixed solvent (Fineeter A-10, Futaba Chemicals Co., Ltd.). The molar ratio of CeO₂ to Al₂O₃ in the coating solution was 2.8:1. The coating solution was then aged at 40°C with continuous stirring for at least 15 hours. The aged coating solution exhibited a transparent pale yellow color.

[0148] A glass product of Test Example 2 was obtained in the same manner as in Test Example 1 except that the above-mentioned coating liquid was used as the coating liquid.

[0149] <Test Example 3>

[0150] A glass substrate with a silicon oxide (SiO2) layer (OptiShower manufactured by Pilkington, Inc.; SiO2 layer thickness 15 nm, hereinafter referred to as "OPS") was used, and a coating layer was formed on the SiO2 layer. A glass product of Experimental Example 3 was obtained in the same manner as in Experimental Example 1 except for this.

[0151] <Test Example 4>

[0152] A glass substrate with a silicon oxide (SiO2) layer (OptiShower, manufactured by Pilkington, Inc.; SiO2 layer thickness 15 nm, hereinafter referred to as "OPS") was used, and a coating layer was formed on the SiO2 layer. A glass product of Experimental Example 4 was obtained in the same manner as in Experimental Example 2, except that the procedure was the same.

[0153] The dynamic friction coefficient of the glass products of Test Examples 1 to 4 was measured according to the above method. The dynamic friction coefficient was measured after coating film formation (initial), after heat treatment (after heat treatment), after standing for 4 weeks, after steam treatment (after steam treatment (1)), after steam treatment, heat treatment, and steam treatment again (after steam treatment (2)). The relative humidity of the atmosphere during standing was approximately 20 to 60%. The results are shown in Table 1.

[0154] Table 2 shows the values ​​and average values ​​of the coefficient of kinetic friction calculated from the friction forces F at five points A to E after heat treatment and after steam treatment (2) for the glass product of Test Example 1.

[0155]

Table 1

[0156]

[0157]

Table 2

[0158]

[0159] <Test Example 5>

[0160] A coating was formed on a glass substrate by PVD. The glass product of Experimental Example 5 was obtained in the same manner as in Experimental Example 2 except for the above. Magnetron cathode sputtering was used as the PVD method. The coating material was deposited using an AC and / or DC magnetron sputtering device, and medium-frequency sputtering was used where appropriate.

[0161] Elemental analysis was performed on the glass product of Test Example 5. Elemental analysis was performed after coating formation (initial), after heat treatment (after heat treatment), after standing for four weeks, and after steam treatment (after steam treatment). The results are shown in Tables 3 and 4.

[0162] <Test Example 6>

[0163] A coating layer was formed on a glass substrate by a sol-gel method. A glass product of Test Example 6 was obtained in the same manner as in Test Example 2 except for the above.

[0164] Elemental analysis was performed on the glass product of Test Example 6. Elemental analysis was performed after coating film formation (initial), after heat treatment (after heat treatment), and after steam treatment (after steam treatment). The results are shown in Tables 3 and 4.

[0165]

Table 3

[0166]

[0167]

Table 4

[0168]

[0169] As shown in Table 1, after the water vapor treatment (1), the dynamic friction coefficient of the coating surface of Test Examples 1 to 4 was reduced to less than 0.50. In addition, as shown in Tables 3 and 4, after the water vapor treatment, the carbon content of the coating surface of Test Examples 5 to 7 was greater than 8 atm%, and the alkali metal content was less than 1.5 atm%. This is believed to be because the alkaline components (alkali metal elements) diffused from the glass substrate to the coating were washed away by the water vapor treatment, and organic matter containing carbon and oxygen elements was adsorbed on the surface of the coating, forming a new layer (easy-to-clean layer). The easy-to-clean layer hindered the alkaline components from diffusing from the glass substrate to the coating. As a result, it is believed that the easy-to-clean property of the coating was quickly restored and the increase in the dynamic friction coefficient of the coating surface was suppressed.

[0170] As shown in Table 1, after the water vapor treatment (2), the dynamic friction coefficient of the coating surfaces of Test Examples 1 to 4 was reduced to below 0.50 again. Thus, the coating's cleanability was quickly and repeatedly restored. Furthermore, as shown in Table 2, after the water vapor treatment (2), the variation in the dynamic friction coefficient of the coating surface of Test Example 1 was ±0.10. Thus, the variation in the coating's cleanability was suppressed.

[0171] exist Figures 3-5 , the results of SEM observation of the coating surface of the glass product produced in Test Example 5 are shown. Figure 3 This is the SEM observation image of the coating after film formation (initial). Figure 4 This is a SEM observation image after heat treatment. Figure 5 This is an SEM observation image after steam treatment (after steam treatment).

[0172] like Figure 3 As shown in the figure, after the coating is formed (initial), fine particles can be observed on the surface of the coating in a regular pattern. Figure 4 As shown in FIG, after heat treatment (after heat treatment), irregular needle-shaped particles can be observed on the surface of the coating. The needle-shaped particles are presumably secondary mixed substances. Figure 5 As shown in the figure, after steam treatment (after steam treatment), the number of needle-shaped particles on the coating surface decreased, and an irregular layer was observed across the entire surface. This irregular layer is presumably a layer that improves cleanability.

Claims

1. A coated glass product comprising a glass substrate and an easy-to-clean coating on the glass substrate, The easy-to-clean coating contains inorganic matter as a main component, The surface of the easy-to-clean coating layer has a carbon content of 8 atm % or more and an alkali metal content of 1.5 atm % or less.

2. The coated glass product according to claim 1, wherein The dynamic friction coefficient of the surface of the easy-to-clean coating is less than 0.

50.

3. The coated glass article according to claim 1, wherein The sum of the content of alkali metal elements and the content of alkaline earth metal elements in the surface of the easy-to-clean coating layer is 10 atm % or less.

4. The coated glass article according to claim 1, wherein The inorganic substance includes at least one selected from the group consisting of rare earth element oxides, zirconium oxides, niobium oxides, and tantalum oxides.

5. The coated glass article according to claim 4, wherein The rare earth element oxide includes at least one selected from the group consisting of cerium oxide, lanthanum oxide, and yttrium oxide.

6. The coated glass article according to claim 1, wherein The coefficient of dynamic friction of the surface of the easy-to-clean coating after the coated glass article is exposed to a heat treatment at 760° C. for 4 minutes is 0.60 or less.

7. The coated glass article according to claim 1, wherein The glass substrate is strengthened glass.

8. The coated glass article according to claim 1, wherein The glass corresponds to at least one selected from the group consisting of building glass, transportation glass, store glass, furniture glass, home appliance glass, signage glass, mobile device glass, and solar cell glass.

9. The coated glass article according to claim 1, wherein: The easy-to-clean coating has at least one function selected from the group consisting of anti-glare and anti-fog.

10. A method for producing a coated glass product, wherein: It has the following processes: A process for forming an easy-to-clean coating containing an inorganic substance as a main component on a glass substrate; The process comprises bringing water or steam into contact with the surface of the easy-to-clean coating in an environment in which carbon and oxygen elements exist.

11. The method for producing a coated glass product according to claim 10, wherein: The inorganic substance includes at least one selected from the group consisting of rare earth element oxides, zirconium oxides, niobium oxides, and tantalum oxides.

12. The method for producing a coated glass product according to claim 11, wherein: The rare earth element oxide includes at least one selected from the group consisting of cerium oxide, lanthanum oxide, and yttrium oxide.

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