Greenhouse and glass plate with coating film

Abstract

A greenhouse according to the present invention is provided with a ceiling part and a coating-film-attached glass plate which is arranged at at least a part of the ceiling part. The coating-film-attached glass plate has a total light transmittance of 90% to 98%, a haze rate of 20% to 80%, and a hemispherical transmittance of 80% to 90%. When a test is carried out in accordance with JIS R 1703-1:2007 in which oleic acid is applied onto a surface of a coating film and is then irradiated with ultraviolet ray having an intensity of 1.0 mW / cm2, the time from the start of the irradiation with ultraviolet ray to the time at which the water contact angle on the surface becomes 5° is 24 hours or less.

Description

Technical Field

[0001] The present invention relates to a greenhouse and a glass plate with a coating film. More specifically, the present invention relates to a glass plate formed with a coating film having a high diffusion transmission function and a photocatalytic function, and a greenhouse provided with the glass plate formed with this coating film.

Background Art

[0002] In the field of greenhouse cultivation, techniques for efficiently introducing sunlight into the greenhouse have been studied. For example, Patent Document 1 discloses a greenhouse provided with a reflector for irradiating plants with sunlight below a translucent roof. However, since it is necessary to adjust the angle of the reflector according to the movement of the sun, this greenhouse has a problem that complicated control is required.

[0003] Greenhouses that prevent a decrease in transmitted light due to roof dirt have also been studied. For example, Patent Document 2 discloses a greenhouse in which a self-propelled cleaning device is arranged on the roof. However, since the arrangement of the cleaning device and the reinforcement of the greenhouse structure are required, this greenhouse has a problem that the manufacturing cost increases.

[0004] Patent Document 3 discloses a technique of using a glass plate including a predetermined texture on the roof of a greenhouse in order to guide sunlight to the whole inside of the greenhouse while avoiding the formation of hot spots on plants. In this technique, the hemispherical transmittance is improved by controlling the texture into a predetermined shape. Specifically, the texture is directly applied to the surface of the glass plate by rolling processing, or is applied by embossing a layer formed on the glass plate by the sol-gel method.

[0005] However, the texture of Patent Document 3 applied by mold pressing such as rolling and embossing is typically a repetition of a pyramid pattern and has a large number of concave portions that become narrower toward the bottom. For this reason, dirt easily adheres to the surface of the glass plate and is not easily removed. The adhesion of dirt becomes a factor that hinders the stable introduction of sunlight over a long period of time.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a new greenhouse suitable for efficiently and stably guiding sunlight into the greenhouse for a long period of time. Another object of the present invention is to provide a light guiding part of such a greenhouse, specifically, a glass plate suitable for use as a roof material.

Means for Solving the Problems

[0008] The present invention is a greenhouse having a ceiling part, wherein at least a part of the ceiling part is provided with a glass plate with a coating film, the glass plate with the coating film has a total light transmittance of 90% to 98%, a haze ratio of 20% to 80%, and a hemispherical transmittance of 80% to 90%, and in accordance with Japanese Industrial Standard (JIS) R 1703-1:2007, after applying oleic acid to the surface of the coating film and then irradiating with ultraviolet rays having an intensity of 1.0 mW / cm 2 when a test is carried out, the time from the start of the ultraviolet ray irradiation until the contact angle of water on the surface becomes 5° is 24 hours or less, and a greenhouse is provided.

[0009] Also, the present invention is A glass plate with a coating film including a glass plate and a coating film, with a total light transmittance of 90% to 98%, a haze ratio of 20% to 80%, and a hemispherical transmittance of 80% to 90%, and in accordance with Japanese Industrial Standard (JIS) R 1703-1:2007, after applying oleic acid to the surface of the coating film, when a test of irradiating ultraviolet rays with an intensity of 1.0 mW / cm 2 is carried out, the time from the start of the irradiation of the ultraviolet rays until the contact angle of water on the surface becomes 5° is 24 hours or less, and a glass plate with a coating film is provided.

[0010] The greenhouse and the glass plate according to the present invention may be provided with a low-emission film together with the above-described light-diffusing film having a light-diffusing function as the coating film. In this case, due to the presence of the low-emission film, the total light transmittance and the hemispherical transmittance will decrease slightly. That is, the present invention provides the following greenhouse and glass plate from another aspect.

[0011] The present invention, from another aspect, is a greenhouse having a ceiling portion, wherein at least a part of the ceiling portion is provided with a glass plate with a coating film, the glass plate with a coating film has a light-diffusing film and a low-emission film as the coating film, the glass plate with a coating film, has a total light transmittance of 70% to 93%, a haze ratio of 20% to 80%, and a hemispherical transmittance of 65% to 88%, and in accordance with Japanese Industrial Standard (JIS) R 1703-1:2007, when a test of irradiating ultraviolet rays with an intensity of 1.0 mW / cm 2 is carried out after applying oleic acid to the surface of the light-diffusing film, the time from the start of the irradiation of the ultraviolet rays until the contact angle of water on the surface becomes 5° is 24 hours or less, and a greenhouse is provided.

[0012] Further, the present invention A glass plate with a coating film including a glass plate and a coating film, The glass plate with the coating film has a light diffusion film and a low-emission film as the coating film, A total light transmittance of 70% to 93%, A haze ratio of 20% to 80%, And a hemispherical transmittance of 65% to 88%, After applying oleic acid to the surface of the light diffusion film in accordance with Japanese Industrial Standard (JIS) R 1703-1:2007, when a test of irradiating ultraviolet rays with an intensity of 1.0 mW / cm 2 Is carried out, the time from the start of irradiation of the ultraviolet rays until the contact angle of water on the surface becomes 5° is 24 hours or less, and a glass plate with a coating film is provided.

Effect of the Invention

[0013] According to the present invention, it is possible to provide a greenhouse suitable for efficiently and stably guiding sunlight therein over a long period of time, and a glass plate suitable for use as a roofing material for such a greenhouse.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description is an example of the present invention, and the present invention is not limited to the following embodiments.

[0016] (Embodiment 1) As shown in FIG. 1, the glass plate with a coating film according to this embodiment includes a glass plate 10 and a coating film 100 formed on the main surface of the glass plate 10. In this specification, the "main surface" means the surface having the largest area of the glass plate.

[0017] The coating film 100 contains silicon oxide fine particles 5 and titanium oxide fine particles 7. The coating film 100 also contains a binder 8. The binder 8 exists at least on the surface of the particles, as well as at the contact portions between the particles and between the particles and the substrate, and plays a role of increasing the bonding force between the particles or between the particles and the substrate at the contact portions. The coating film 100 may be formed on one main surface of the glass plate 10. The coating film 100 may be formed only on a part of one main surface of the glass plate 10. One main surface of the glass plate 10 may be substantially covered with the coating film 100.

[0018] The silicon oxide fine particles 5 are, for example, spherical particles. At least a part of the silicon oxide fine particles 5, preferably 50% or more, may exist in the state of primary particles in the height direction of the coating, in other words, without being stacked on another silicon oxide fine particle 5. The average particle size of the silicon oxide fine particles 5 may be 0.05 μm to 50 μm, may be 0.05 μm to 20 μm, may be 0.05 μm to 10 μm, or may be 0.1 μm to 5 μm. Since the refractive index of silicon oxide is relatively low, the apparent refractive index of the coating film 100 is reduced by the silicon oxide fine particles 5. Furthermore, spherical particles containing silicon oxide with a well - aligned particle size are produced at low cost on a commercial scale and are easily available from the viewpoints of quantity, quality, and cost. By appropriately adjusting the average particle size of the silicon oxide fine particles 5, the haze ratio of the coating film 100 can be improved. That is, by using the silicon oxide fine particles 5 having an appropriate average particle size in the coating film 100, the incident light can be transmitted while being well diffused.

[0019] In this specification, the "average particle size" may be the particle size (d50) corresponding to 50% volume cumulative obtained from the particle size distribution measured on a volume basis by the laser diffraction scattering method for the silicon oxide fine particle dispersion or the titanium oxide fine particle dispersion used in the preparation of the coating film 100. The silicon oxide fine particles 5 and the titanium oxide fine particles 7 can be discriminated by performing a composition analysis using energy - dispersive X - ray spectroscopy (EDX).

[0020] The content of the silicon oxide fine particles 5 in the coating film 100 may be 10 mass% to 90 mass%, may be 22 mass% to 85 mass%, may be 22 mass% to 77.5 mass%, may be 25 mass% to 74.5 mass%, may be 30 mass% to 69.5 mass%, and further may be 35 mass% to 64.5 mass%.

[0021] The silicon oxide fine particles 5 contained in the coating film 100 may be solid and substantially spherical. "Substantially spherical" means that when the fine particles are observed with a scanning electron microscope (SEM), the ratio of the maximum diameter to the minimum diameter (maximum diameter / minimum diameter) is 1.0 to 1.5.

[0022] The average particle diameter of the titanium oxide fine particles 7 may be 0.005 μm to 0.1 μm, may be 0.01 μm to 0.05 μm, or may be 0.01 μm to 0.03 μm. By appropriately adjusting the average particle diameter of the titanium oxide fine particles 7, the surface area per unit mass of titanium oxide can be increased. Thereby, the photocatalytic function of the coating film 100 can be improved. Further, by appropriately adjusting the average particle diameter of the titanium oxide fine particles 7, a coating liquid in which the titanium oxide fine particles 7 are uniformly dispersed can be obtained.

[0023] The content of the titanium oxide fine particles 7 in the coating film 100 may be 0.1 mass% to 20 mass%, may be 0.5 mass% to 20 mass%, may be 1 mass% to 20 mass%, and further may be 4 mass% to 18 mass%. The content of the titanium oxide fine particles 7 in the coating film 100 is preferably 0.5 mass% to 5 mass%. When it is desired to enhance the photocatalytic function, the content of the titanium oxide fine particles 7 may be 7 mass% or more. In particular, when using template glass as the glass plate 10, the content of the titanium oxide fine particles 7 may be 10 mass% or more, and further 15 mass% or more.

[0024] The titanium oxide fine particles 7 contained in the coating film 100 are solid and substantially spherical. By including the titanium oxide fine particles 7 in the coating film 100, a photocatalytic function can be imparted to the coating film 100. When the titanium oxide fine particles 7 are contained, when the coating film 100 is irradiated with light having a predetermined wavelength (for example, 400 nm or less), the organic substances attached to the coating film 100 are decomposed, and the coating film 100 becomes hydrophilic.

[0025] By appropriately adjusting the ratio of the average particle size of the titanium oxide fine particles 7 to the average particle size of the silicon oxide fine particles 5, it is possible to impart a photocatalytic function while suppressing a decrease in visible light transmittance. The ratio of the average particle size of the titanium oxide fine particles 7 to the average particle size of the silicon oxide fine particles 5 may be, for example, 0.001 to 0.3, may be 0.002 to 0.2, or may be 0.002 to 0.1.

[0026] In the coating film 100, the ratio of the mass of the titanium oxide fine particles 7 to the mass of the silicon oxide fine particles 5 is not particularly limited, and is, for example, 0.01 to 0.30. Thereby, the coating film 100 can surely have a high diffusion transmission function and can surely have a high photocatalytic function. The ratio of the mass of the titanium oxide fine particles 7 to the mass of the silicon oxide fine particles 5 may be 0.02 to 0.25, may be 0.03 to 0.24, or may be 0.05 to 0.23.

[0027] The coating film 100 may contain a binder 8. The binder 8 preferably contains at least one selected from the group consisting of silicon oxide, zirconium oxide, and aluminum oxide, and more preferably contains silicon oxide and / or zirconium oxide. The binder 8 may contain silicon oxide (SiO2) and zirconium oxide (ZrO2). The binder 8 may contain silicon oxide and may not contain zirconium oxide and aluminum oxide.

[0028] As a source of silicon oxide in the binder 8, a hydrolyzable silicon compound such as silicon alkoxide can be used. Preferably, the silicon alkoxide is tetramethoxysilane, tetraethoxysilane, or tetraisopropoxysilane. Also, as the silicon alkoxide, trifunctional or bifunctional silicon alkoxides such as methyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, phenyltriethoxysilane, glycidoxyalkyltrialkoxysilane, other epoxy silanes, acrylic silanes, methacrylic silanes, and amino silanes can be mentioned. As the glycidoxyalkyltrialkoxysilane, 3-glycidoxypropyltrimethoxysilane can be mentioned. These hydrolyzable silicon compounds are hydrolyzed and polycondensed by the sol-gel method to form silicon oxide in the binder 8. However, the silicon alkoxide is not particularly limited as long as it is a compound capable of forming silicon oxide by the sol-gel method.

[0029] As a source of zirconium oxide in the binder 8, a zirconium compound can be used. The zirconium compound may be a zirconium alkoxide. Preferably, the zirconium compound is a water-soluble inorganic zirconium compound added to the coating liquid for forming the coating film 100. Also, preferably, the zirconium compound is zirconium halide or zirconium nitrate. In this case, the preferred zirconium halide is zirconium chloride. By containing zirconium oxide, the coating film 100 can have higher chemical durability and preferably an appropriate refractive index. Also, by containing zirconium oxide in the binder 8, the coating film 100 can also improve its durability against alkalis.

[0030] The content rate of zirconium oxide contained in the binder 8 may be 5 mass% to 50 mass%, may be 6 mass% to 40 mass%, or may be 7 mass% to 30 mass% with respect to the total amount of the binder 8. On the other hand, in another preferred embodiment, the content rate of zirconium oxide is preferably 3 mass% to 8 mass%, and preferably 5 mass% to 7 mass%.

[0031] The content rate of the binder 8 in the coating film 100 may be 5 mass% to 90 mass%, may be 5 mass% to 79.5 mass%, 5 mass% to 77.5 mass%, 22 mass% to 77.5 mass%, 25 mass% to 74.5 mass%, 30 mass% to 69.5 mass%, or may further be 35 mass% to 64.5 mass%.

[0032] The content rate of silicon oxide contained in the binder 8 in the coating film 100 may be 100 mass%, may be 5 mass% to 97 mass%, may be 10 mass% to 97 mass%, 15 mass% to 95 mass%, or may further be 20 mass% to 93 mass%.

[0033] In the coating film 100, the total content of SiO2 contained in the silicon oxide fine particles 5 and the SiO2 contained in the binder 8, the content of TiO2 contained in the titanium oxide fine particles 7, and the content of ZrO2 are not particularly limited. In the coating film 100, the total content of SiO2 contained in the silicon oxide fine particles 5 and the SiO2 contained in the binder 8 may be 70% by mass to 99% by mass, may be 79% by mass to 98% by mass, may be 79% by mass to 96.5% by mass, may be 80% by mass to 95% by mass, may be 85% by mass to 95% by mass, or may be 85% by mass to 93% by mass. In the coating film 100, the content of TiO2 may be 0.1% by mass to 20% by mass, may be 0.5% by mass to 20% by mass, may be 1% by mass to 20% by mass, or may be 2.5% by mass to 20% by mass. In the coating film 100, the content of ZrO2 may be 5% by mass to 45% by mass, may be 10% by mass to 40% by mass, or may be 20% by mass to 30% by mass. In the coating film 100, the content of ZrO2 is preferably 0% by mass to 10% by mass, more preferably 1% by mass to 7% by mass, and even more preferably 2% by mass to 7% by mass. By appropriately adjusting the content of each component contained in the coating film 100, the glass plate with the coating film can have a more excellent diffusion transmission function. Further, the glass plate with the coating film can also have an excellent photocatalytic function.

[0034] By appropriately adjusting the content of the silicon oxide fine particles 5 in the coating film 100, the diffusion transmittance can be further improved. By appropriately adjusting the content of the titanium oxide fine particles 7 in the coating film 100, the coating film 100 can have a higher photocatalytic function. By appropriately adjusting the content of the binder 8 in the coating film 100, the coating film 100 can have high strength. By appropriately adjusting the content of zirconium oxide in the coating film 100, the coating film 100 can have high strength and can further improve the durability against alkalis.

[0035] As shown in FIG. 1, the coating film 100 includes silicon oxide fine particles 5, titanium oxide fine particles 7, and a binder 8. The coating film 100 has convex portions 3 containing silicon oxide fine particles 5 therein. The silicon oxide fine particles 5 contained in the convex portions 3 may be single or plural. The coating film 100 has the convex portions 3 and a region 4 surrounding the convex portions 3. The region 4 is also the region between the plurality of convex portions 3. At least a part of the titanium oxide fine particles 7 is present in a dispersed state in the matrix 9 in the region 4. The matrix 9 in the region 4 is composed of at least a part of the binder 8. The convex portions 3 protrude upward from the region 4. In the convex portions 3, the surface of the silicon oxide fine particles 5 protruding from the region 4 is substantially covered with a layer containing at least one selected from a part of the titanium oxide fine particles 7 and a part of the binder 8. In the convex portions 3, the surface of the silicon oxide fine particles 5 protruding from the region 4 may be substantially covered with a layer substantially composed of a part of the titanium oxide fine particles 7 and a part of the binder 8. In the region 4, the main surface of the glass plate 10 is substantially covered with the matrix 9 in which at least a part of the titanium oxide fine particles 7 is dispersed. "Substantially consisting of" means that the content rate of the component in the layer is 90% by mass or more, further 95% by mass or more, and particularly 99% by mass or more. "Substantially covered" means that 90% or more, further 95% or more of the target surface is covered.

[0036] The average value of the height H of the convex portions 3 is not particularly limited, and it is desirable that it is 2 times or more, further 2.5 times or more of the thickness T of the coating film 100 in the region 4, and 2 times or less, further 1.5 times or less of the average particle diameter of the silicon oxide fine particles 5. Here, the height H of the convex portions 3 is the height from the main surface of the glass plate 10 on which the coating film 100 is formed. Specifically, H and T can be determined by observing the cross-section of the coating film 100 with SEM and taking the average value of the measured values at arbitrary 50 locations.

[0037] The thickness T of the coating film 100 in the region 4 is, for example, 10 nm to 5 μm, more preferably 30 nm to 3 μm, and particularly preferably 70 nm to 1 μm. The average value of the height H of the convex portion 3 is, for example, in the range of 90% to 130%, more preferably 100% to 120% of the average particle diameter of the silicon oxide fine particles 5.

[0038] The glass plate 10 may be a template glass or a float plate glass. The arithmetic mean roughness Ra of the surface of the float plate glass is preferably 1 nm or less, more preferably 0.5 nm or less. Here, the arithmetic mean roughness Ra is a value defined in Japanese Industrial Standard (JIS) B 0601:2013.

[0039] The float plate glass means a glass plate manufactured by the float process. The glass plate manufactured by the float process has a bottom surface and a top surface. The bottom surface is one main surface of the glass plate, and the top surface is the main surface of the glass plate on the side opposite to the bottom surface. The bottom surface is a surface formed by the glass that was in contact with the molten tin of the float bath in the glass plate forming process by the float process. The coating film 100 may be formed on at least a part of the top surface. In this case, the coating film 100 can contribute to the improvement of weather resistance. In particular, when ZrO2 is contained in the coating film 100, the weather resistance of the coating film 100 can be further improved.

[0040] The coating film 100 may be formed on at least a part of the bottom surface. In this case, the coating film 100 can more sufficiently improve the visible light transmittance of the coated glass plate as compared with the case where the coating film 100 is formed on at least a part of the top surface.

[0041] The surface of the mold plate glass has macroscopic unevenness with a size visible to the naked eye. The macroscopic unevenness refers to unevenness with an average interval RSm on the order of millimeters. The average interval RSm means the average value of the interval of one cycle of valleys and peaks obtained from the points where the roughness curve intersects the average line. The macroscopic unevenness can be confirmed when the evaluation length in the roughness curve is set to the order of centimeters. The average interval RSm of the unevenness on the surface of the mold plate glass may be 0.3 mm or more, 0.4 mm or more, or 0.45 mm or more. The average interval RSm may be 2.5 mm or less, 2.1 mm or less, 2.0 mm or less, or 1.5 mm or less. The unevenness on the surface of the mold plate glass preferably has a maximum height Rz of 0.5 μm to 10 μm, particularly 1 μm to 8 μm, together with the average interval RSm within the above range. The average interval RSm and the maximum height Rz are values defined in JIS B 0601:2013. The surface unevenness of the glass plate which is the mold plate glass desirably has an arithmetic mean roughness Ra of 0.3 μm to 5.0 μm, particularly 0.4 μm to 2.0 μm, and further 0.5 μm to 1.2 μm, together with the average interval RSm and the maximum height Rz within the above range. Note that even for the mold plate glass, in the surface roughness measurement where the evaluation length in the roughness curve is several hundred nm, it may have an arithmetic mean roughness Ra of several nm or less (for example, 1 nm or less). That is, the surface of the mold plate glass may have excellent smoothness microscopically. Examples of the surface roughness measurement with an evaluation length of several hundred nm include atomic force microscope (AFM) observation. In the present embodiment, the organic substances that tend to stay in the concave portions of the mold plate glass are decomposed by the photocatalytic function of the titanium oxide fine particles 7 and are easily removed.

[0042] As described in Patent Document 3 (paragraph 0015), in the pattern formed by embossing such as rolling, it is difficult to make its size less than 1 mm. Therefore, the technique of scattering light relying on the texture by embossing is not suitable for preventing up to minute hot spots. In contrast, the light scattering technique using the minute convex portions 3 containing the silicon oxide fine particles 5 is suitable for preventing minute hot spots.

[0043] Even when the glass plate 10 is a template glass, the average value of the height H of the convex portion 3 is not particularly limited, and it is desirable that the average value of the height H of the convex portion 3 is not less than twice the thickness T of the coating film 100 in the region 4 and not more than twice the average particle diameter of the silicon oxide fine particles 5.

[0044] The composition of the glass plate 10 may be the same as that of ordinary architectural plate glass. The content of iron oxide in the glass plate 10 may be 0.06% by mass or less or 0.02% by mass or less in terms of Fe2O3. Iron oxide is a typical coloring component. When the glass plate 10 is colored glass, the content of iron oxide in the glass plate 10 may be 0.3% by mass to 1.5% by mass.

[0045] The thickness of the glass plate 10 is not particularly limited, and for example, it is 0.5 mm to 15 mm.

[0046] The glass plate with a coating film can have a high total light transmittance. That is, the glass plate with a coating film can have, for example, a total light transmittance of 70% or more, 85% or more, 87% or more, and further 90% or more, and in some cases 94% or more. The total light transmittance is measured by using an integrating sphere type spectrophotometer in a state where the glass plate with a coating film is closely fixed to the light incident opening of the integrating sphere, and is the average value of the transmittance in the measurement wavelength range. In the glass plate 10, light is incident from the main surface on which the coating film 100 is formed. The total light transmittance may be a value measured in accordance with JIS K 7361-1:1997.

[0047] The upper limit of the total light transmittance of the glass plate with a coating film is not particularly limited, and may be 99%, 96%, or 93%.

[0048] The glass plate with a coating film may have a high haze ratio. That is, the glass plate with a coating film may have a haze ratio of 20% or more, 30% or more, and even 40% or more. The haze ratio is a value measured, for example, in accordance with JIS K 7136:2000. The upper limit of the haze ratio is not particularly limited and may be 80%, 70%, 65%, or 63%.

[0049] The glass plate with a coating film has a high total light transmittance and a high haze ratio. According to the glass plate with a coating film, a high total light transmittance and a high haze ratio are compatible. For this reason, the light incident on the glass plate with a coating film is transmitted while diffusing at a high rate. Therefore, when light is incident on the glass plate with a coating film, uniform light is likely to be emitted over the entire glass plate with a coating film. Also, when looking at the light source from the emission side of the glass plate with a coating film, the shape of the light source is less conspicuous. According to the greenhouse equipped with the glass plate with a coating film, sunlight can penetrate better into the greenhouse without being locally irradiated in the greenhouse.

[0050] The glass plate with a coating film can have a high hemispherical transmittance. That is, the glass plate with a coating film can have, for example, a hemispherical transmittance of 65% or more, and can have a hemispherical transmittance of 76% or more, and further 80% or more. The upper limit of the hemispherical transmittance is not particularly limited, and it may be 95%, may be 90%, or may be 86%. The hemispherical transmittance means the average value of the transmittances measured over a plurality of incident angles. In the measurement of the hemispherical transmittance in the present embodiment, for example, the measurement method of the total light transmittance by the single beam method shown in JIS K 7361-1:1997 is applied. Specifically, first, the glass plate with a coating film is set in a specimen holder. The light of a D65 light source is made incident on the specimen, and the light transmitted through the glass plate with a coating film is measured. In this measurement, the incident angle of the light with respect to the specimen is changed every 10° from 0° to 90°, and the light transmitted through the glass plate with a coating film is measured at each incident angle. Then, the ratio of the transmitted light intensity to the incident light intensity is measured at each incident angle. The hemispherical transmittance in the present embodiment is the average value of the ratios of the transmitted light intensity to the incident light intensity at a measurement wavelength of 400 nm to 700 nm.

[0051] The glass plate with a coating film can have a high hemispherical transmittance. Therefore, the glass plate with a coating film can also be efficiently irradiated with sunlight inside the greenhouse even with respect to the change in the incident angle from when the sun rises to when it sets.

[0052] The glass plate with a coating film can have self-cleaning performance. That is, on the surface of the coating film 100, for example, the critical contact angle with respect to water defined in JIS R 1703-1:2007 is preferably 5° or less. Thus, the coating film 100 can have the performance of easily washing away dirt.

[0053] In the glass plate with a coating film, for example, the time tc is 24 hours or less. The time tc is in accordance with JIS R 1703-1:2007. After oleic acid is applied to the surface of the coating film 100, 1.0 mW / cm 2When a test of irradiating ultraviolet rays with a certain intensity is carried out, it is the time from the start of ultraviolet ray irradiation until the contact angle of water on the surface of the coating film 100 becomes 5°. The shorter the time tc is, the more it means that the glass plate with the coating film can exhibit a high photocatalytic function.

[0054] The time tc of the glass plate with the coating film may be 20 hours or less, may be 18 hours or less, or may be 15 hours or less.

[0055] (Method for manufacturing a glass plate with a coating film) An example of the method for manufacturing a glass plate with a coating film will be described. The glass plate with the coating film can be manufactured by applying a coating liquid for forming the coating film 100 to a part of one main surface of the glass plate and drying and curing the coating film of the coating liquid.

[0056] The coating liquid may contain a source of binder 8, silicon oxide fine particles 5, and titanium oxide fine particles 7. The source of binder 8 is prepared, for example, by adding a hydrolysis catalyst and a hydrolyzable silicon compound such as silicon alkoxide while stirring a predetermined solvent. The hydrolysis of the hydrolyzable silicon compound is preferably carried out in a solution in which the silicon oxide fine particles 5 are present. This is because the polycondensation reaction between the silanol groups present on the surface of the silicon oxide fine particles 5 and the silanol groups generated by the hydrolysis of the hydrolyzable silicon compound is promoted. As a result, in the binder 8, the proportion of silicon oxide contributing to the binding force of the silicon oxide fine particles 5 increases. Specifically, the coating liquid is prepared, for example, by adding a hydrolysis catalyst and a hydrolyzable silicon compound such as silicon alkoxide while stirring a dispersion of the silicon oxide fine particles 5. In some cases, the silicon oxide fine particles 5 may be added after the hydrolysis of the hydrolyzable silicon compound to prepare the coating liquid. The titanium oxide fine particles 7 may be added at any stage of the preparation of the coating liquid. The coating liquid is prepared, for example, by adding a hydrolysis catalyst and a hydrolyzable silicon compound such as silicon alkoxide while stirring a mixed liquid obtained by mixing a dispersion of the silicon oxide fine particles 5 and a dispersion of the titanium oxide fine particles 7. When the coating film contains zirconium oxide, a zirconium compound is also added to the coating liquid. As the hydrolysis catalyst, either an acid or a base can be used. However, from the viewpoint of the stability of the coating liquid, the use of an acid, particularly an inorganic acid, especially hydrochloric acid or nitric acid, is desirable. As the hydrolysis catalyst, an acid having a high ionization degree in an aqueous solution can be used. Specifically, an acid having an acid dissociation constant pKa of 2.5 or less can be used. When the acid is a polybasic acid, pKa means the first acid dissociation constant. Desirable acids as the hydrolysis catalyst include (i) volatile inorganic acids such as hydrochloric acid and nitric acid, (ii) organic acids such as trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid, (iii) polybasic acids such as maleic acid, phosphoric acid, and oxalic acid, (iv) sulfuric acid, and (v) sulfamic acid.An acidic hydrolysis catalyst can disperse silicon oxide fine particles 5 and titanium oxide fine particles 7 better than a basic hydrolysis catalyst.

[0057] The coating liquid contains a solvent. The solvent mainly contains, for example, an organic solvent miscible with water and having a boiling point of 150°C or lower. The boiling point of the organic solvent mainly contained in the solvent is, for example, 70°C or higher. The coating liquid may further contain a high-boiling organic solvent miscible with water and the aforementioned organic solvent and having a boiling point exceeding 150°C. The boiling point of the high-boiling organic solvent is, for example, 200°C or lower. Examples of the high-boiling organic solvent include propylene glycol, diacetone alcohol, hexylene glycol, and 3-methoxybutanol. The boiling point of propylene glycol is 187°C. The boiling point of diacetone alcohol is 168°C. The boiling point of hexylene glycol is 198°C. The boiling point of 3-methoxybutanol is 161°C. When the coating liquid contains a high-boiling organic solvent, a uniform and continuous film without defects can be easily obtained, and the durability of the coating film 100 can be improved. The high-boiling organic solvent can reduce the volatilization rate of the solvent and keep the volatilization rate in-plane constant during the process of drying the liquid film containing the coating liquid. Thereby, the dispersion stability of the silicon oxide fine particles 5 and the dispersion stability of the titanium oxide fine particles 7 in the liquid film are maintained, and aggregation of these fine particles can be suppressed during the drying process. In addition, a decrease in the meniscus due to local drying of the liquid film is suppressed, and leveling of the liquid film is promoted. The content of the high-boiling organic solvent is not particularly limited and is, for example, 1% to 20% by mass in the coating liquid.

[0058] The method of applying the coating liquid to the main surface of the glass plate 10 is not particularly limited, and spin coating, roll coating, bar coating, dip coating, or spray coating can be used. From the viewpoints of mass productivity and homogeneity of the appearance of the coating film, the coating liquid may be applied to the main surface of the glass plate 10 by roll coating or bar coating. From the viewpoint of mass productivity, the coating liquid may be applied to the main surface of the glass plate 10 by spray coating.

[0059] The coating film 100 is formed, for example, by applying a coating liquid to the glass plate 10 and then heating the glass plate 10 such that the maximum temperature of the glass plate 10 is 200°C or higher and 350°C or lower, and the time during which the temperature of the glass plate 10 is 200°C or higher is 5 minutes or less. The coating film 100 is formed, for example, by applying a coating liquid to the glass plate 10 and then heating the glass plate 10 such that the maximum temperature of the glass plate 10 is 120°C or higher and 250°C or lower, and the time during which the temperature of the glass plate 10 is 120°C or higher is 3 minutes or less. The coating film 100 is formed, for example, by applying a coating liquid to the glass plate 10 and then heating the glass plate 10 such that the maximum temperature of the glass plate 10 is 100°C or higher and 250°C or lower, and the time during which the temperature of the glass plate 10 is 100°C or higher is 2 minutes or less. The coating film 100 can be formed by heating at a relatively low temperature. Thereby, a coating film 100 having a high reflection suppression function, a high photocatalytic function, or high chemical durability can be provided. The method for drying and curing the coating film of the coating liquid is not particularly limited, and the coating film of the coating liquid can be dried and cured by heat drying or hot air drying using a far-infrared heating furnace.

[0060] The coating film 100 may be formed, for example, by the following method. After applying the coating liquid to the glass plate 10, solvents and the like contained in the coating liquid are removed by heating. Thereafter, the glass plate 10 is placed in a heating furnace and heated, for example, in a heating furnace set at 760°C such that the glass plate 10 reaches about 600°C. Thereby, since metal oxides are generated from the metal compounds contained in the coating liquid, a binder 8 can be formed on the coating film 100.

[0061] (Embodiment 2) FIG. 2 shows another example of a glass plate on which the coating film according to the present embodiment is formed. The same reference numerals are given to the elements common to the coating film 100 according to Embodiment 1 and the coating film 200 according to the present embodiment, and the description thereof may be omitted.

[0062] As shown in Fig. 2, the glass plate with a coating film according to this embodiment includes a glass plate 10 and a coating film 200 formed on the main surface of the glass plate 10. In the coating film 200, the silicon oxide fine particles 5 include two types of silicon oxide fine particles having different average particle diameters. That is, the silicon oxide fine particles 5 included in the coating film 200 include first silicon oxide fine particles 51 and second silicon oxide fine particles 52.

[0063] The coating film 200 includes first silicon oxide fine particles 51, second silicon oxide fine particles 52, and titanium oxide fine particles 7. The coating film 200 also includes a binder 8. The binder 8 exists at least on the surface of the particles and at the contact portions between the particles and between the particles and the substrate, and plays a role of increasing the bonding force between the particles or between the particles and the substrate at the contact portions. The coating film 200 may be formed on one main surface of the glass plate 10. The coating film 200 may be formed only on a part of one main surface of the glass plate 10.

[0064] The first silicon oxide fine particles 51 are, for example, spherical particles. At least a part of the first silicon oxide fine particles 51, preferably 50% or more, may exist in the state of primary particles in the height direction of the coating, in other words, without laminating with another first silicon oxide fine particle 51. The average particle diameter of the first silicon oxide fine particles 51 may be 0.1 μm to 50 μm, may be 0.1 μm to 20 μm, may be 0.3 μm to 10 μm, may be 0.5 μm to 10 μm, or may be 0.5 μm to 5 μm. By appropriately adjusting the average particle diameter of the first silicon oxide fine particles 51, the incident light can be transmitted while being well diffused. In another preferred embodiment, the average particle diameter of the first silicon oxide fine particles 51 is preferably 0.7 μm to 5 μm, and more preferably 1.5 μm to 4 μm.

[0065] The silicon dioxide fine particles 52 are, for example, spherical particles. The average particle diameter of the silicon dioxide fine particles 52 may be 0.01 μm to 0.2 μm, may be 0.05 μm to 0.155 μm, or may be 0.05 μm to 0.125 μm. By appropriately adjusting the average particle diameter of the silicon dioxide fine particles 52, the coating film 200 can obtain a desired reflection suppression function.

[0066] The ratio of the average particle diameter of the silicon dioxide fine particles 52 to the average particle diameter of the silicon monoxide fine particles 51 is not particularly limited. By appropriately adjusting the ratio of the average particle diameter of the silicon dioxide fine particles 52 to the average particle diameter of the silicon monoxide fine particles 51, the incident light can be diffused well and transmitted. Further, the coating film 200 can obtain a desired reflection suppression function. That is, the coating film 200 can achieve both a high total light transmittance and a high haze ratio. The ratio of the average particle diameter of the silicon dioxide fine particles 52 to the average particle diameter of the silicon monoxide fine particles 51 may be 1 / 100 to 1 / 10, or may be 1 / 50 to 1 / 20.

[0067] In the coating film 200, the ratio of the mass of the silicon monoxide fine particles 51 to the mass of the silicon dioxide fine particles 52 may be 6 / 4 to 10 / 1, or may be 7 / 3 to 9.5 / 1. Thereby, the coating film 200 has a higher diffusion transmission function and a higher reflection suppression function.

[0068] The ratio of the average particle diameter of the titanium oxide fine particles 7 to the average particle diameter of the silicon dioxide fine particles 52 may be 1 / 20 to 1 / 1.1, or may be 1 / 10 to 1 / 2.

[0069] As shown in FIG. 2, the coating film 200 includes silicon monoxide fine particles 51, silicon dioxide fine particles 52, titanium oxide fine particles 7, and a binder 8. The coating film 200 has a convex portion 3 that contains silicon monoxide fine particles 51 therein. The silicon monoxide fine particles 51 contained in the convex portion 3 may be single or plural. The coating film 200 has the convex portion 3 and a region 4 surrounding the convex portion 3. The region 4 is also the region between a plurality of convex portions 3. In the region 4, at least a part of the silicon dioxide fine particles 52 and at least a part of the titanium oxide fine particles 7 are present in a state of being dispersed in a matrix 9. The matrix 9 in the region 4 is composed of at least a part of the binder 8. The convex portion 3 protrudes upward from the region 4. In the convex portion 3, the surface of the silicon monoxide fine particles 51 protruding from the region 4 is substantially covered with a layer containing at least one selected from the group consisting of a part of the silicon dioxide fine particles 52, a part of the titanium oxide fine particles 7, and a part of the binder 8. In the convex portion 3, the surface of the silicon monoxide fine particles 51 protruding from the region 4 may be substantially covered with a layer substantially composed of a part of the silicon dioxide fine particles 52, a part of the titanium oxide fine particles 7, and a part of the binder 8. In the region 4, the main surface of the glass plate 10 is substantially covered with a matrix 9 in which at least a part of the silicon dioxide fine particles 52 and at least a part of the titanium oxide fine particles 7 are dispersed.

[0070] The average value of the height H of the convex portion 3 is not particularly limited, and it is desirable that it is 2 times or more, further 2.5 times or more, the thickness T of the coating film 200 in the region 4, and 2 times or less, further 1.5 times or less, the average particle diameter of the silicon monoxide fine particles 51. Here, the height H of the convex portion 3 is the height from the main surface of the glass plate 10 on which the coating film 200 is formed. Specifically, H and T can be determined by observing the cross section of the coating film 200 with SEM and taking the average value of the measured values at any 50 locations.

[0071] The thickness T of the coating film 200 in region 4 is, for example, 10 nm to 5 μm, more preferably 30 nm to 3 μm, and particularly 70 nm to 1 μm. The average value of the height H of the convex portions 3 is, for example, in the range of 90% to 130%, more preferably 100% to 120% of the average particle diameter of the first silicon oxide fine particles 51.

[0072] (Embodiment 3) As shown in FIG. 3, the glass plate with a coating film may have a light diffusion film 30 and a low-emissivity film 20 as the coating film 300. The light diffusion film 30 may have the characteristics of the coating film described in Embodiments 1 and 2. The low-emissivity film 20 may be formed on at least one of the main surfaces of the glass plate 10. In the glass plate 10, the light diffusion film 30 and the low-emissivity film 20 may be formed on the same main surface of the glass plate 10. In this case, the low-emissivity film 20 and the light diffusion film 30 may be laminated in this order from the main surface side of the glass plate 10. In the glass plate 10, the light diffusion film 30 may be formed on the main surface of the glass plate 10 opposite to the main surface on which the low-emissivity film 20 is formed (FIG. 3). In this case, the low-emissivity film 20 is preferably formed on at least a part of the top surface of the float glass. And in this case, it is effective for reducing the heat transfer coefficient to use it in a greenhouse with the low-emissivity film 20 facing the indoor side. Examples of the low-emissivity film 20 include a laminate including a transparent conductive film. By using the low-emissivity film 20, the greenhouse can have improved heat insulation properties. Note that the glass plate constituting the glass plate with a coating film may be a single glass plate, or a laminated body such as a multilayer glass in which a plurality of glass plates are spaced apart and held by a spacer and the space between the glass plates is made airtight by a peripheral seal, or a laminated glass in which a plurality of glass plates are integrated via an intermediate film.

[0073] (Transparent Conductive Film) As a first example of the transparent conductive film, a film containing fluorine-doped tin oxide and having a thickness of 200 nm to 400 nm can be mentioned. This film may be a film consisting essentially of fluorine-doped tin oxide. The transparent conductive film of the first example preferably has a thickness of 300 nm to 400 nm. When the transparent conductive film of the first example is used, the underlayer film described later preferably has a two-layer structure (for example, the underlayer film of the second example).

[0074] As a second example of the transparent conductive film, a film containing fluorine-doped tin oxide and having a thickness of 400 nm to 800 nm can be mentioned. This film may be a film consisting essentially of fluorine-doped tin oxide. The transparent conductive film of the second example preferably has a thickness of 500 nm to 700 nm. When the transparent conductive film of the second example is used, the underlayer film described later preferably has a two-layer structure (for example, the underlayer film of the second example).

[0075] As a third example of the transparent conductive film, a transparent conductive film including a first transparent conductive layer containing antimony-doped tin oxide and having a thickness of 100 nm to 300 nm, and a second transparent conductive layer containing fluorine-doped tin oxide and having a thickness of 150 nm to 400 nm can be mentioned. The first transparent conductive layer may be a layer consisting essentially of antimony-doped tin oxide. The second transparent conductive layer may be a layer consisting essentially of fluorine-doped tin oxide. The transparent conductive film of the third example may consist essentially of the first transparent conductive layer and the second transparent conductive layer. In the third example, the first transparent conductive layer and the second transparent conductive layer are laminated in this order, for example, from the main surface side of the glass plate. In the transparent conductive film of the third example, the first transparent conductive layer preferably has a thickness of 150 nm to 200 nm. In the transparent conductive film of the third example, the second transparent conductive layer preferably has a thickness of 200 nm to 300 nm. When the transparent conductive film of the third example is used, the underlayer film described later preferably has a two-layer structure (for example, the underlayer film of the second example).

[0076] As a fourth example of the transparent conductive film, a film including dielectric layers and metal layers alternately can be mentioned. The dielectric layer can be composed of an oxide, a nitride, or the like. The oxide can be, for example, zinc oxide, tin oxide, and silicon oxide. The nitride can be, for example, silicon nitride. The metal layer typically contains silver. This film may include additional layers such as a sacrificial layer and an underlayer in addition to the dielectric layer and the metal layer.

[0077] (Underlayer film) The low-emissivity film may further include an underlayer film. The underlayer film is disposed, for example, between the glass plate and the transparent conductive film, and may be in direct contact with each of the glass plate and the transparent conductive film.

[0078] As a first example of the underlayer film, a film containing silicon oxycarbide (SiOC) as a main component and having a thickness of 20 nm to 120 nm can be mentioned. In this specification, the "main component" means the component most contained on a mass basis. The underlayer film of the first example may consist substantially of silicon oxycarbide. The underlayer film of the first example preferably has a thickness of 30 nm to 100 nm, and more preferably has a thickness of 30 nm to 60 nm.

[0079] As a second example of the underlayer film, an underlayer film including a first underlayer containing tin oxide as a main component and having a thickness of 10 nm to 90 nm, and a second underlayer containing SiO2 as a main component and having a thickness of 10 nm to 90 nm can be mentioned. The underlayer film of the second example may consist of an underlayer film composed of a first underlayer consisting substantially of tin oxide and a second underlayer consisting substantially of SiO2. In the second example, the first underlayer and the second underlayer are laminated in this order, for example, from the main surface side of the glass plate 10. In the underlayer film of the second example, the first underlayer preferably has a thickness of 10 nm to 70 nm, and more preferably has a thickness of 12 nm to 40 nm. In the underlayer film of the second example, the second underlayer preferably has a thickness of 10 nm to 70 nm, and more preferably has a thickness of 12 nm to 40 nm.

[0080] As a third example of the underlayer film, there is an underlayer film including a first underlayer containing SiO2 as a main component and having a thickness of 10 nm to 30 nm, a second underlayer containing tin oxide as a main component and having a thickness of 10 nm to 90 nm, and a third underlayer containing SiO2 as a main component and having a thickness of 10 nm to 90 nm. The underlayer film of the third example may be an underlayer film composed of a first underlayer substantially made of SiO2, a second underlayer substantially made of tin oxide, and a third underlayer substantially made of SiO2. In the third example, the first underlayer, the second underlayer, and the third underlayer are laminated in this order, for example, from the main surface side of the glass plate 10. In the underlayer film of the third example, the first underlayer preferably has a thickness of 10 nm to 20 nm. In the underlayer film of the third example, the second underlayer preferably has a thickness of 10 nm to 70 nm, and more preferably has a thickness of 12 nm to 40 nm. In the underlayer film of the third example, the third underlayer preferably has a thickness of 10 nm to 70 nm, and more preferably has a thickness of 12 nm to 40 nm.

[0081] When the low-emissivity film 20 and the light-diffusing film 30 are used as the coating film, the total light transmittance of the glass plate with the coating film is slightly lower than that when the glass plate alone is used. The decrease in transmittance due to the low-emissivity film 20 may be expected to be about 3% to 20%. In an embodiment including the low-emissivity film 20 and the light-diffusing film 30 as the coating film, the glass plate with the coating film has, for example, a total light transmittance of 70% to 93%, preferably 75% to 85%, and, for example, a hemispherical transmittance of 65% to 88%, preferably 70% to 83%. The haze rate is hardly affected by the formation of the low-emissivity film 20 or may increase slightly.

[0082] (greenhouse) The types of greenhouses can be classified into single - pitched roof type, double - pitched roof type, or three - quarter roof type according to the shape of the roof and its structure. Further, as greenhouses, there are also single - span type and multi - span type. The shape of the greenhouse is not particularly limited as long as the glass plate with a coating film described above can be used. Depending on the type of plants to be cultivated or the type of crops to be cultivated, the glass plate with a coating film may be used for the entire surface of the greenhouse or may be used for a part of the greenhouse. As long as the glass plate with a coating film is used, the design of the greenhouse can be freely changed according to the type of plants, the type of crops, and / or the installation area of the greenhouse.

[0083] The greenhouse has a ceiling part. The glass plate with a coating film may be used for the ceiling part. The glass plate with a coating film may be used for the entire surface of the ceiling part of the greenhouse or may be used for a part of the ceiling part of the greenhouse. The ceiling part may have an inclined roof. The direction of the inclined roof is not particularly limited. The inclined roof may be inclined by an inclination angle α with respect to the horizontal plane. The inclination angle α may be 15° or more with respect to the horizontal plane, or may be 20° or more. The upper limit of the inclination angle α is not particularly limited and may be 70°, 67°, 50°, 45°, or 35° with respect to the horizontal plane. In the ceiling part of the greenhouse, due to the fact that the roof is inclined by the inclination angle α with respect to the horizontal plane, the dirt deposited on the roof is likely to flow down by rainwater or the like.

[0084] By using the glass plate with a coating film for a part of the ceiling part of the greenhouse, light can penetrate better into the greenhouse without the sunlight being locally irradiated into the greenhouse. Further, even when dirt such as dust adheres to the surface of the glass plate with a coating film, the photocatalytic function decomposes the organic matter adhering to the surface of the glass plate with a coating film, weakens the adhesion force of the organic matter, and enables the washing of the organic matter by rainwater or the like.

[0085] A skylight may be provided in the ceiling part of the greenhouse. In this case, the glass plate with a coating film may constitute a part of the skylight.

Example

[0086] Hereinafter, the present invention will be described in more detail with reference to examples. First, a method for evaluating each property of the glass plate with a coating film according to each example or comparative example will be described.

[0087] (Total light transmittance) In accordance with Japanese Industrial Standard (JIS) K 7361-1:1997, the total light transmittance of the glass plate with a coating film according to the examples and comparative examples was measured. For the measurement of the total light transmittance, a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH2000) was used. The transmittance with respect to visible light incident in a state where the glass plate with a coating film according to the examples and comparative examples was fixed in close contact with the light incident opening of the integrating sphere was measured. The results are shown in Tables 1 and 2.

[0088] (Haze ratio) In accordance with JIS K 7136:2000, the haze ratio of the glass plate with a coating film according to the examples and comparative examples was determined. For the measurement of the haze ratio, a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH2000) was used. For the glass plate with a coating film according to the examples and comparative examples, the haze ratio with respect to the incident visible light was measured. The results are shown in Tables 1 and 2.

[0089] (Hemispherical transmittance) For the measurement of the hemispherical transmittance, a single-beam spectrophotometer (manufactured by Perkin Elmer, LAMBDA1050) equipped with ARTA (Automated Reflectance / Transmittance Analyzer) was used. Specifically, the total light transmittance with respect to incident light having a wavelength of 400 nm to 700 nm was measured in accordance with JIS K7361-1:1997. However, the angle of incidence of light with respect to the glass plate with a coating film was changed every 10° from 0° to 90°. The total light transmittance was measured at each angle of incidence, and the average value thereof was taken as the hemispherical transmittance. Also, the sample size was cut out to be a square shape with a side length of 50 mm. Also, the spot diameter of the light source in the sample was 10 mm. The results are shown in Tables 1 and 2.

[0090] (Measurement of water contact angle) In accordance with JIS R 1703-1:2007, the water contact angles of the coating films according to the examples and comparative examples were measured. First, an oleic acid solution adjusted to 0.5 vol% was prepared by diluting oleic acid with n-heptane. The oleic acid solution was applied to the glass plate with the coating film using a dip coater. Specifically, the glass plate with the coating film was immersed in the oleic acid solution for 10 seconds and then pulled up at a speed of 60 cm / min. Subsequently, the test piece was obtained by drying the glass plate with the coating film at 70 °C for 15 minutes.

[0091] When a test was carried out to irradiate the test piece prepared as described above with ultraviolet rays (black light blue type ultraviolet fluorescent lamp, wavelength: 368 nm, intensity: 1.0 mW / cm 2 ), the time tc from the start of ultraviolet irradiation until the water contact angle on the surface of the coating film reached 5° was measured. A contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.) was used to measure the water contact angle on the surface of the coating film. The results are shown in Tables 1 and 2.

[0092] (Example 1) 61.1 g of commercially available propylene glycol monomethyl ether, 12.5 g of tetraethoxysilane, 6.5 g of purified water, 15.3 g of silicon monoxide fine particle dispersion liquid (solid content concentration 48.4%, average particle size 3.5 μm), 3.7 g of silicon dioxide fine particle dispersion liquid (solid content concentration 22.9%, average particle size 0.1 μm), and 1.0 g of 1N nitric acid (hydrolysis catalyst) were weighed into a glass container. This glass container was stirred in an oven maintained at 40 °C for 8 hours to obtain a high-concentration solution. The solid content concentration in this high-concentration solution was 12%, and the mass ratio of silicon monoxide fine particles, silicon dioxide fine particles, and the binder converted to SiO2 in the high-concentration solution was 6.3:0.7:3.

[0093] 83.3 g of the aforementioned high-concentration solution, 8.0 g of propylene glycol monomethyl ether, 1.2 g of a zirconium compound (concentration 25 wt% as ZrO2), 1.7 g of a titanium oxide fine particle dispersion (concentration 30 wt% as TiO2, primary particle size (average particle size) 10 nm, dispersion medium: water), and 5.0 g of a surfactant (manufactured by Shin-Etsu Silicone Co., Ltd., KP-341, diluted to 1 wt% with propylene glycol monomethyl ether) were stirred and mixed to obtain a coating solution. The solid content concentration in the coating solution was 10.8%. The concentration of the solid content with respect to the entire coating liquid according to Example 1 was 10.8 mass%. In the solid content of the coating liquid according to Example 1, silicon monoxide fine particles were contained at 58.3 mass%, silicon dioxide fine particles were contained at 6.5 mass%, titanium oxide fine particles were contained at 4.6 mass%, tetraethoxysilane converted to SiO2 was contained at 27.8 mass%, and the zirconium compound converted to ZrO2 was contained at 2.8 mass%. The mass of the solid content in the coating liquid is defined as the sum of the mass of tetraethoxysilane (source of silicon oxide in the binder) converted to SiO2, the mass of the solid content of the silicon monoxide fine particle dispersion, the mass of the solid content of the silicon dioxide fine particle dispersion, the mass of the solid content of the titanium oxide fine particle dispersion, and the mass of the zirconium compound optionally added converted to ZrO2.

[0094] The coating liquid was applied to the surface of a washed glass plate (100×100 mm; thickness 3 mm; float plate glass) by the spray coating method. The coating liquid was continuously stirred until immediately before application. The glass plate coated with the coating liquid was dried in an oven set at 200 °C, and then fired in an electric furnace set at 610 °C for 3.5 minutes to obtain a glass plate with a coating film according to Example 1. For the glass plate with a coating film according to Example 1, the above-mentioned respective characteristics were evaluated. The evaluation results are shown in Table 1. The result of observing the surface of the formed coating film with an optical microscope is shown in Figure 4. The result of observing the cross-section of the formed coating film with a scanning electron microscope (SEM) is shown in Figure 5.

[0095] (Examples 2 to 6) In the same manner as in Example 1, glass plates with a coating film according to Examples 2 to 6 were obtained.

[0096] (Examples 7 and 8) In the same manner as in Example 1, except that silicon monoxide fine particles with an average particle size of 0.9 μm were used, glass plates with a coating film according to Examples 7 and 8 were obtained.

[0097] (Example 9) First, as a float plate glass with a low-emissivity film, a glass plate with a transparent conductive film (Low-E glass manufactured by Nippon Sheet Glass Co., Ltd.) was cut out so that its main surface had a square shape with a side length of 10 cm and washed. This glass plate with a transparent conductive film had a SnO2 layer (first underlayer) with a physical film thickness of 25 nm, a SiO2 layer (second underlayer) with a physical film thickness of 25 nm, and a SnO2:F layer (transparent conductive layer) with a physical film thickness of 340 nm laminated in this order on one main surface of a 3-mm-thick float plate glass.

[0098] In the same manner as in Example 1, except that a glass plate with a transparent conductive film was used, a glass plate with a coating film according to Example 9 was obtained. However, the coating liquid was applied to the main surface of the glass plate on the side opposite to the main surface of the glass plate on which the low-emissivity film was formed.

[0099] (Example 10) 22.5 g of propylene glycol monomethyl ether, 1.1 g of tetraethoxysilane, 12.7 g of silicon dioxide fine particle dispersion (solid content concentration: 22.9%, primary particle size (average particle size): 75 nm, dispersion medium: water), 2.2 g of titanium oxide fine particle dispersion, and 0.4 g of 1N hydrochloric acid (hydrolysis catalyst) were weighed into a glass container. This glass container was stirred in an oven maintained at 40°C for 8 hours to obtain a high-concentration solution. The solid content concentration in this high-concentration solution was 10%, and the mass ratio of silicon dioxide fine particles, titanium oxide fine particles, and the binder converted to SiO2 in the high-concentration solution was 75:17:8. Next, 260.9 g of propylene glycol monomethyl ether, 0.06 g of a silicone surfactant (manufactured by Momentive, CS3505), and 39.0 g of the aforementioned high-concentration solution were stirred and mixed to obtain a coating solution. The solid content concentration in the coating solution was 1.3%.

[0100] The coating liquid was spray-coated on the uneven surface of a washed glass plate (manufactured by Nippon Sheet Glass Co., Ltd.; 300 mm × 100 mm; thickness: 3 mm; template glass). The template glass used had a soda-lime silicate composition, and its uneven surface was represented by an arithmetic mean roughness Ra of 0.8 μm, a maximum height Rz of 4.5 μm, and an average spacing RSm of 1.1 mm. The coating liquid was continuously stirred until immediately before coating. The glass plate coated with the coating liquid was dried in an oven set at 400°C, and then fired in an electric furnace set at 760°C for 5 minutes to obtain a glass plate with a coating film according to Example 10.

[0101] (Comparative Example 1) A glass plate with a coating film according to Comparative Example 1 was obtained in the same manner as in Example 1, except that the coating liquid was prepared such that the coating film did not contain titanium oxide fine particles and the solid content concentration was as described in Table 2.

[0102] (Comparative Example 2) Except that the coating film does not contain titanium oxide fine particles and the coating liquid was prepared so that the solid content concentration was as described in Table 2, a glass plate with a coating film according to Comparative Example 2 was obtained in the same manner as in Example 10.

[0103]

Table 1

[0104]

Table 2

[0105] The haze ratio of the glass plates with coating films according to Examples 1 to 10 was 41.6% or more, having a high diffusion transmittance. The total light transmittance of the glass plates with coating films according to Examples 1 to 10 was 82.5% or more, transmitting light at a high rate. The hemispherical transmittance of the glass plates with coating films according to Examples 1 to 10 was 80.2% or more, having a high transmittance even when the incident angle was large. The tc of the glass plates with coating films according to Examples 1 to 10 was 15 hours or less, having a high photocatalytic function. In the glass plates with coating films according to Comparative Examples 1 and 2, two types of silicon oxide fine particles were contained, having a high haze ratio and a high total light transmittance. The tc of the glass plates with coating films according to Comparative Examples 1 and 2 was 48 hours or more. The coating films according to Comparative Examples 1 and 2 did not contain titanium oxide fine particles, and the photocatalytic function was reduced.

[0106] FIG. 4 is a diagram showing the result of observing the surface of the coating film 100 formed according to Example 1 with an optical microscope. As shown in FIG. 4, a coating film 200 was formed on the glass plate 10. FIG. 5 is a diagram showing the result of observing the cross section of the coating film 200 formed according to Example 1 with an SEM. As shown in FIG. 5, a coating film 200 was formed on the surface of the glass plate 10.

Industrial Applicability

[0107] According to the present invention, there are provided a glass plate having a coating suitable for use in a greenhouse, having a high diffusion transmission function, and excellent in removability of dirt such as dust, and a greenhouse including the glass plate having the coating formed thereon. This glass plate is suitable for use as a glass article intended for long-term use outdoors.

Claims

1. A greenhouse having a ceiling portion, wherein at least a part of the ceiling portion is provided with a glass plate with a coating film, the glass plate with the coating film includes a float plate glass and a coating film formed on a main surface of the float plate glass, the coating film contains silicon oxide fine particles, titanium oxide fine particles and a binder, the silicon oxide fine particles include first silicon oxide fine particles and second silicon oxide fine particles, the coating film has a convex portion and a region surrounding the convex portion, an average value of a height H of the convex portion from the main surface is not less than twice a thickness T of the coating film in the region surrounding the convex portion, the convex portion contains therein a single or a plurality of the first silicon oxide fine particles, an average particle diameter of the first silicon oxide fine particles is from 1.5 μm to 50 μm, an average particle diameter of the second silicon oxide fine particles is from 0.05 μm to 0.125 μm, a ratio of a mass of the first silicon oxide fine particles to a mass of the second silicon oxide fine particles is from 6 / 4 to 10 / 1, in the region, at least a part of the second silicon oxide fine particles and at least a part of the titanium oxide fine particles are present in a state of being dispersed in a matrix composed of at least a part of the binder, the glass plate with the coating film has a total light transmittance of 92.8% to 98%, a haze ratio of 41.6% to 80%, and a hemispherical transmittance of 80% to 90%. In accordance with Japanese Industrial Standard (JIS) R 1703-1:2007, after applying oleic acid to the surface of the coating film, a test was conducted by irradiating ultraviolet rays with an intensity of 1.0 mW / cm 2 When the time from the start of irradiation of the ultraviolet rays until the contact angle of water on the surface becomes 5° is 24 hours or less, the greenhouse.

2. The average particle diameter of the silicon oxide fine particles is from 0.05 μm to 50 μm, the average particle diameter of the titanium oxide fine particles is from 0.01 μm to 0.03 μm, a ratio of the average particle diameter of the titanium oxide fine particles to the average particle diameter of the silicon oxide fine particles is from 0.001 to 0.3, the greenhouse according to claim 1.

3. The coating film, in terms of mass%, contains 22% to 85% of the silicon oxide fine particles 0.5% to 20% of the titanium oxide fine particles 5% to 77.5% of the binder, the greenhouse according to claim 2.

4. The binder is SiO 2 and ZrO 2 The greenhouse according to claim 3, comprising

5. The coating film, in terms of mass%, SiO contained in the silicon oxide fine particles 2 and SiO contained in the binder 2 with a total of 79% to 98% TiO contained in the titanium oxide fine particles 2 0.5% to 20% ZrO 2 containing 0% to 10% the greenhouse according to claim 3 or 4.

6. The coating film, in terms of mass%, SiO contained in the silicon oxide fine particles 2 and SiO contained in the binder 2 with a total of 79% to 98% TiO contained in the titanium oxide fine particles 2 0.5% to 20% ZrO 2 containing 1% to 7% the greenhouse according to claim 5.

7. The coating film, in terms of mass%, The SiO contained in the silicon oxide fine particles 2 and the SiO contained in the binder 2 with a total of 85% to 95% TiO contained in the titanium oxide fine particles 2 0.5% to 20% ZrO 2 containing 1% to 7% the greenhouse according to claim 6.

8. The average particle diameter of the first silicon oxide fine particles is from 1.5 μm to 10 μm, The average particle diameter of the second silicon oxide fine particles is 0.05 μm to 0.125 μm, and the greenhouse according to any one of claims 2 to 7.

9. The ratio of the mass of the first silicon oxide fine particles to the mass of the second silicon oxide fine particles is 7 / 3 to 9.5 / 1, and the greenhouse according to claim 8.

10. In the convex portion, the surface of the first silicon oxide fine particles protruding from the region is substantially covered by a layer containing at least one selected from the group consisting of a part of the second silicon oxide fine particles, a part of the titanium oxide fine particles, and a part of the binder. In the region surrounding the convex portion, the main surface of the glass plate is substantially covered by the matrix in which at least a part of the second silicon oxide fine particles and at least a part of the titanium oxide fine particles are dispersed, and the greenhouse according to claim 8 or 9.

11. The average value of the height H is not more than twice the average particle diameter of the first silicon oxide fine particles, and the greenhouse according to claim 8.

12. At least a part of the titanium oxide fine particles is present in the region between the convex portions in a state of being dispersed in a matrix composed of at least a part of the binder. In the convex portion, the surface of the first silicon oxide fine particles protruding from the region is substantially covered by a layer containing at least one selected from the group consisting of a part of the titanium oxide fine particles and a part of the binder. In the region surrounding the convex portion, the main surface of the glass plate is substantially covered by the matrix in which at least a part of the titanium oxide fine particles are dispersed, and the greenhouse according to any one of claims 3 to 7.

13. The ceiling portion is inclined by an inclination angle α with respect to the horizontal plane, and satisfies 15° ≤ α ≤ 67°, and the greenhouse according to any one of claims 1 to 12.

14. A greenhouse provided with a ceiling portion, At least a part of the ceiling portion is provided with a glass plate with a coating film, The glass plate with a coating film includes a float plate glass and a coating film formed on the main surface of the float plate glass. The glass plate with a coating film has a light diffusion film and a low-emissivity film as the coating film. The light diffusion film contains silicon oxide fine particles, titanium oxide fine particles, and a binder. The silicon oxide fine particles include first silicon oxide fine particles and second silicon oxide fine particles. The light diffusing film has convex portions and a region surrounding the convex portions. The average value of the height H of the convex portions from the main surface is at least twice the thickness T of the coating film in the region surrounding the convex portions. The convex portions contain therein single or plural first silicon oxide fine particles. The average particle diameter of the first silicon oxide fine particles is 1.5 μm to 50 μm. The average particle diameter of the second silicon oxide fine particles is 0.05 μm to 0.125 μm. The ratio of the mass of the first silicon oxide fine particles to the mass of the second silicon oxide fine particles is 6 / 4 to 10 / 1. In the region, at least a part of the second silicon oxide fine particles and at least a part of the titanium oxide fine particles are present in a dispersed state in a matrix composed of at least a part of the binder. The glass plate with the coating film has a total light transmittance of 75% to 93%, a haze ratio of 40% to 80%, and a hemispherical transmittance of 65% to 88%. In accordance with Japanese Industrial Standard (JIS) R 1703-1:2007, after applying oleic acid to the surface of the light diffusing film, when a test of irradiating ultraviolet rays with an intensity of 1.0 mW / cm 2 is carried out, the time from the start of irradiation of the ultraviolet rays until the contact angle of water on the surface becomes 5° is 24 hours or less, greenhouse.

15. A greenhouse according to claim 14, wherein the glass plate with the coating film has the light diffusing film on one main surface of the glass plate as the coating film, and has the low-emissivity film on the other main surface.

16. A glass plate with a coating film including a glass plate and a coating film, wherein the glass plate is a float plate glass, the coating film is formed on the main surface of the float plate glass, the coating film includes silicon oxide fine particles, titanium oxide fine particles, and a binder, the silicon oxide fine particles include first silicon oxide fine particles and second silicon oxide fine particles, the coating film has convex portions and a region surrounding the convex portions, the average value of the height H of the convex portions from the main surface is at least twice the thickness T of the coating film in the region surrounding the convex portions, the convex portions contain therein single or plural first silicon oxide fine particles, the average particle diameter of the first silicon oxide fine particles is 1.5 μm to 50 μm, the average particle diameter of the second silicon oxide fine particles is 0.05 μm to 0.125 μm, the ratio of the mass of the first silicon oxide fine particles to the mass of the second silicon oxide fine particles is 6 / 4 to 10 / 1, and in the region, at least a part of the second silicon oxide fine particles and at least a part of the titanium oxide fine particles are present in a dispersed state in a matrix composed of at least a part of the binder. An overall light transmittance of 92.8% to 98%, a haze ratio of 41.6% to 80%, and a hemispherical transmittance of 80% to 90%. In accordance with Japanese Industrial Standard (JIS) R 1703-1:2007, after applying oleic acid to the surface of the coating film, a test is carried out by irradiating ultraviolet rays with an intensity of 1.0 mW / cm 2 When the test is carried out, for the glass plate with the coating film, the time from the start of irradiation of the ultraviolet rays until the contact angle of water on the surface becomes 5° is 24 hours or less.

17. A glass plate with a coating film, comprising a glass plate and a coating film, wherein the glass plate is a float plate glass, the coating film is formed on the main surface of the float plate glass, the glass plate with a coating film has a light diffusing film and a low-emissivity film as the coating film, the light diffusing film contains silicon oxide fine particles, titanium oxide fine particles, and a binder, the silicon oxide fine particles include first silicon oxide fine particles and second silicon oxide fine particles, the light diffusing film has convex portions and regions surrounding the convex portions, the average value of the height H of the convex portions from the main surface is not less than twice the thickness T of the coating film in the regions surrounding the convex portions, the convex portions contain therein single or plural first silicon oxide fine particles, the average particle diameter of the first silicon oxide fine particles is 1.5 μm to 50 μm, the average particle diameter of the second silicon oxide fine particles is 0.05 μm to 0.125 μm, the ratio of the mass of the first silicon oxide fine particles to the mass of the second silicon oxide fine particles is 6 / 4 to 10 / 1, in the regions, at least a part of the second silicon oxide fine particles and at least a part of the titanium oxide fine particles are present in a dispersed state within a matrix formed from at least a part of the binder, an overall light transmittance of 75% to 93%, a haze ratio of 40% to 80%, and a hemispherical transmittance of 65% to 88%. In accordance with Japanese Industrial Standard (JIS) R 1703-1:2007, after applying oleic acid to the surface of the light diffusing film, a test is carried out by irradiating ultraviolet rays with an intensity of 1.0 mW / cm 2 When the time from the start of irradiation of the ultraviolet rays until the contact angle of water on the surface becomes 5° is 24 hours or less, a glass plate with a coating film.

18. The glass plate with a coating film according to Claim 17, wherein the glass plate with a coating film has, as the coating film, the light diffusing film on one main surface of the glass plate, and the low-emissivity film on the other main surface.

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