WO2003087004A1 - Solar heat cutoff glass and solar heat cutoff method using same - Google Patents

Abstract

An inexpensive solar heat cutoff glass for reducing the heat load due to solar radiation without marring the transparency to visible light that glass intrinsically has. Formed by application on one side of a glass substrate is a coating having a visible light transmittance larger than that of the glass substrate and having a solar heat absorbance and a radiation heat absorbance in the wavelength band of normal temperature heat radiation both smaller than those of the glass substrate. This solar heat cutoff glass is so disposed that the coating surface faces to the inside of a closed space, thus the heat radiation from the glass heated by the solar heat toward the inside is cut off, and the heat load of the inside is reduced.

Description

 Description Solar heat shielding glass and solar heat shielding method using the same

 The present invention relates to a novel solar heat shielding glass having a glass substrate provided with a coating having a small heat radiation in a wavelength range of room temperature heat radiation. More specifically, the present invention provides a solar heat capable of blocking solar heat radiation by blocking heat radiation (heat radiation in a wavelength range of room temperature heat radiation) from a glass surface heated and heated by the solar radiation. The present invention relates to a shielding glass and a method for shielding solar heat using the same. Background art

 Generally, in buildings and vehicles that have enclosed spaces with glass windows, the glass surface is heated by solar radiation and becomes hot, and the solar heat absorbed by the glass is radiated into enclosed spaces such as indoors and vehicles. The internal temperature of the air conditioner rises, which may cause various problems such as the air conditioner becoming ineffective, especially in summer.

 In order to block such radiation of solar heat, heat-absorbing glass that absorbs solar radiation and heat-reflecting glass that reflects solar radiation using various inorganic or organic substances have been developed. However, these materials use organic or inorganic substances that absorb the heat itself, or metals or inorganic materials that reflect the heat, in order to block the solar heat that is transmitted through the glass and directly enters the enclosed space. Is what you do. In order to enhance the solar heat blocking effect of such heat absorbing glass or heat reflecting glass that directly absorbs or reflects solar heat, there is a method of increasing the amount of substances that absorb or reflect solar heat. However, there are practical disadvantages such as an increase in cost or a decrease in transparency due to a significant decrease in transparency in the visible light band.

In addition, glass that absorbs solar heat has the disadvantage that the heat absorbed by the glass is radiated again after a while, so that the heat load inside the enclosed space cannot be greatly reduced. On the other hand, glass that reflects solar heat does not cause re-emission because it hardly absorbs wavelengths in the wavelength range of room temperature heat radiation, but these also use metals or ceramics that reflect infrared light, and so on. However, there was a disadvantage that the light was reflected to visible light and the inside became dark.

To solve these problems, a metal layer is placed in the center, and a metal cover is formed on both sides to adjust the refractive index to increase the visible light transmittance to about 70%. wear and multilayer systems insulation material to reflect infrared (JP 5 9 1 0 3 7 4 9) by, S N_〇 ₂ as low-emissivity film to reduce the radiation: with F film, color unevenness glass was used low-E glass and low-E glass obtained by laminating S N_〇 ₂ film and S i 0 ₂ film in between the glass substrate in order to reduce the article (JP 2 0 0 1 2 4 4 9 ), But the transparency in the visible light band is still not enough. In addition, in order to produce these glasses and films, it is necessary to use equipment such as vacuum evaporation and sputtering in order to coat metals and ceramics on the glass, which is economically disadvantageous.

 For these reasons, an inexpensive solar heat shielding glass that has high transparency in the visible light band and can reduce the heat load due to solar radiation has been awaited. Disclosure of the invention

 As described above, in the market today, it has been desired to provide inexpensively glass that can reduce the heat load due to irradiation in summer or the like without impairing the transmission of visible light inherent in glass. In particular, there was a great demand for vehicles that required transparency in the visible light band.

 However, the above-mentioned prior art has to sacrifice the transmission of visible light in order to reduce the heat load due to solar radiation. Have not been able to get.

 An object of the present invention is to provide an inexpensive solar heat shielding glass capable of solving such a problem and reducing the heat load due to the solar radiation without impairing the transparency of the original visible light of the glass. I do.

The present inventors have conducted intensive studies in view of the above problems, and have found that a visible Using a composite glass coated with a coating so that the light transmittance is large and the radiant heat absorptance in the wavelength range of solar heat radiation and room temperature heat radiation is small, and the surface of the film is enclosed space, that is, inside buildings and vehicles. By arranging it facing away, heat radiation in the wavelength range of room temperature heat radiation from the glass substrate that has absorbed solar radiation and became hot can be effectively blocked, and the heat load inside the enclosed space can be reduced. And completed the present invention.

 That is, the present invention relates to the solar radiation shielding glass described in the following (1) to (5) and a solar radiation shielding method using the glass.

 (1) On one surface of the glass substrate, the visible light transmittance is larger than the visible light transmittance of the glass substrate, and both the solar heat absorption and the radiant heat absorption in the wavelength range of room temperature heat radiation are the solar heat of the glass substrate. A solar heat shielding glass provided with a coating having a smaller absorptance and a lower radiant heat absorption in the wavelength region of room temperature heat radiation.

 (2) The coating has a visible light transmittance of 90% or more, a solar heat absorption of 0.01 to 11%, and a radiant heat absorption of 0.01 to 20% in a wavelength region of room temperature heat radiation. (1) The solar heat shielding glass according to (1).

 (3) The solar heat shielding glass according to (1) or (2), wherein a wavelength range of room temperature heat radiation in the radiant heat absorption rate is 5 to 50 m.

 (4) The material for forming the film is a plastic selected from the group consisting of an acrylic resin, a silicone resin, and a styrene resin, and is a solar heat shield according to any one of (1) to (3). Glass.

(5) The solar heat shielding glass according to any one of (1) to (4) is arranged such that the glass substrate surface faces a side to which solar heat is applied, and heat from the coating surface side is provided. A method for shutting out solar radiation, which comprises blocking radiation. Glass absorbs radiation heat such as solar radiation radiated from sunlight. Here, the wavelength range of the solar light is 0.3 <um to 3.0 μιη, but in general, even in the case of a general transparent plate glass, not only absorption in the infrared band of 2.5 im or more, but also 2 It also absorbs visible light and near-infrared light below 5 μπι. The temperature of the glass rises due to the absorption of the solar radiation, and the heat absorbed by the glass is transferred to the indoor side or outside air by convection and radiation. Heat is dissipated.

 Here, since the convection of air inside a closed space such as a room or a car is small, convection heat transfer is relatively small. Radiative heat transfer, on the other hand, is a direct heat transfer between the glass and the objects or air inside, and is hardly affected by the convection of air. In other words, the heat that enters the space from the heated glass has a higher rate of heat transfer by radiation in the enclosed space.

 The solar heat absorbed by the glass increases as the thickness of the glass increases, and it exceeds about 6% for 3 mm glass. And the heat radiation from the glass causes a large heat load in the closed space. Therefore, it is considered that the heat load in the enclosed space can be reduced by preventing the solar heat absorbed by the glass from being incident on the enclosed space by re-radiation and radiating a large amount to the outside air.

 In addition, the range of the wavelength emitted from sunlight is 0.3 μπ! 3μ πι, but the range of wavelengths emitted from the glass whose temperature has risen by absorbing solar radiation is 5 μνα to 50 m, which is the wavelength range of room temperature thermal radiation. Therefore, in order to prevent the heat absorbed by the glass from being incident on the inside of the enclosed space due to radiation, it is necessary to block thermal radiation in a wavelength range of at least 5 / zm to 50 μm.

The heat transferred from the solid into the air is conducted through the solid, and then transferred from the solid surface into the air by convection and radiation. Therefore, in order to block the heat radiation from the glass, the emissivity of the glass surface should be reduced. That is, the absorptance of the glass surface in the wavelength region of room temperature heat radiation may be reduced. That is, the wavelength range of room temperature heat radiation! What is necessary is just to form a film made of an object having a small absorption rate at 50 to 50 μm on the surface of the glass. By arranging the surface on which the coating is formed toward the inside of the enclosed space, the amount of radiant heat transfer between the glass and the object inside is reduced. On the other hand, when the film formed on the glass surface itself has a higher solar heat absorption rate than glass, the solar heat transmitted through the glass is absorbed more by the film than when only the glass is used, and the heat is radiated to the outside air. Most of the heat absorbed by the coating is released inside the enclosed space because the glass impedes heat dissipation. In other words, if the solar heat absorption rate of the coating is higher than that of glass, the temperature in the enclosed space will increase even if the radiant heat absorption rate in the wavelength range of room temperature heat radiation is lower than that of glass. Therefore, the wave of radiation of the coating It can be seen that not only the radiant heat absorption rate in the long range but also the solar radiation absorption rate is related to the radiant heat transfer from the glass to the inside of the enclosed space.

 In general, organic substances, unlike inorganic substances, have low absorption and reflection in the visible light band and the infrared band, and large transmission. Therefore, if a coating made of plastics with low absorption and reflection in the infrared band and high transmission is formed on one side of the glass and the coating is arranged toward the inside of the closed space, the visible light transmittance of the glass can be reduced. We thought that it was possible to reduce the heat load inside the space with little decrease, and found through experiments the relationship between the visible light transmittance of the coating, the solar heat absorption rate, and the absorption rate in the wavelength range for room temperature heat radiation, and completed the present invention. Things. Hereinafter, the present invention will be described in detail.

 1. Solar heat shielding glass

 The solar radiation blocking glass of the present invention has a specific coating on one surface of a glass substrate.

 (1) Glass substrate

 The kind of glass used for the glass substrate in the present invention is not particularly limited, and may be not only a transparent plate glass but also a heat ray absorbing glass, a heat ray reflecting glass and the like. Any material having the property of radiating the solar heat absorbed by the solar radiation can exert the effect of the present invention sufficiently.

 Heat-absorbing glass, heat-reflecting glass, and the like further form the coating of the present invention on one surface to prevent direct sunlight and also prevent heat radiation from the glass that has become high due to absorption of solar radiation. As a result, the effect of reducing the heat load of the present invention is further improved.

The thickness of the glass substrate is not particularly limited, but is preferably 0.1 to 20 mm, and more preferably 1 to 20 mm. Even with the same glass material, the greater the thickness, the greater the solar heat absorption and the greater the heat radiation from the glass, and the greater the effect of blocking the heat radiation from the glass. (2) Coating

 In the present invention, the coating provided on one side of the glass substrate has a visible light transmittance higher than that of the glass substrate, and both a solar heat absorption coefficient and a radiation heat absorption coefficient in a wavelength region of room temperature heat radiation are those of the glass substrate. It is smaller.

①Visible light transmittance, solar heat absorption and radiant heat absorption

 Here, the relationship between the amount of radiated heat transfer and the visible light transmittance, solar heat absorption, and radiated heat absorption of the substance is described below.

 <Relationship between radiant heat transfer and emissivity of object>

 Radiant heat Q in radiative heat transfer is expressed by the following equation, which can be transmitted even in vacuum. '

σ · ε · (Τ / 1 0 0) ⁴

Where σ is the Stephan Boltzmann constant, _ε is the emissivity of the object, and Τ is the absolute temperature of the object. As is clear from this equation, the lower the emissivity, the less heat is radiated from the object.

Further, the heat transfer amount Q ₂ by radiant heat transfer (radiant heat transfer) transferred from the object surface on the object such as a fluid of low temperature zone, expressed by the formula as follows.

_{Q 2 = σ X f (ε} ) X [(Τ Bruno 1 0 0) ⁴ one (T _0/1 0 0) ^4] However, sigma is Sutefuan 'Boltzmann constant, f (epsilon) is the radiation heat transfer between the object 1 \ is the surface temperature of the object (K), T. Is the surface temperature (K) of the object in the low-temperature zone.

 As is clear from this equation, if the radiation coefficient of the radiant heat transfer between the object surfaces is reduced, the radiant heat transfer between the objects is reduced.

 And the radiation heat transfer coefficient is expressed by the following equation.

f) = 1Z (1 J + (1 A ₂ ) — 1

However, ε = emissivity of the material in the high-temperature band side, ε ₂ = emissivity of the material in the low-temperature band side Therefore, if one emissivity between the objects is reduced, the radiant heat transfer coefficient f ( _ε ) becomes smaller and the radiation The amount of heat transfer is reduced.

In other words, if the same object is on both sides of the glass, heat transfer due to radiation from the glass surface We will be the same. Therefore, if a film made of a material with a low emissivity is formed on one side of the glass, the emissivity of the surface on which the film is formed becomes small, and the radiative heat transfer coefficient between the surface on which the film is formed and the object also becomes small, and the film becomes It decreases with respect to the amount of radiant heat transfer from the unformed glass surface.

 In other words, if a coating made of a material with a low emissivity is formed on the indoor surface of window glass provided in a closed building or vehicle, the indoor surface of glass that has become hot due to solar radiation and the indoor (closed) The amount of radiated heat transfer between materials such as air in the space (inside the space) and the objects in the space is reduced, and the heat absorbed by the glass is largely radiated to the outside air, so the internal heat load is reduced.

<Relationship between the emissivity of the object and the radiant heat absorption rate>

In general, an object such as metal absorbs part of the solar radiation and reflects all the others, so the following relational expression “ _α + ρ = 1” is established between the absorption rate _α and the reflectance ρ. It turns out that it does not pass in the visible and infrared bands. However, objects such as glass and plastic are gray bodies that partially absorb, partially reflect, and partially transmit solar heat. In the case of such a gray body, the following relational expression `` + ρ + τ = 1 '' holds between the absorptance α, reflectivity and transmittance τ, and there is radiant heat transmitted in the visible light and infrared bands. I understand.

 According to Kirch-Hoff's law, the rate of absorption and the emissivity of such heat are equal, so to block the radiant heat from glass that has become hot due to solar radiation, the wavelength range of heat radiation from such glass, What is necessary is to select a substance that has high transmission in the wavelength range of room temperature heat radiation and low radiant heat absorption rate (radiant heat absorption rate). At this time, the wavelength range of room temperature heat radiation is in the range of 5 to 50 wni.

 That is, if a material such as plastics having a small radiant heat absorption in the wavelength range of 5 to 50 m is selected and a film is formed on the glass surface, the amount of radiant heat transfer from the surface of the film is reduced.

As described above, the coating used for the solar radiation blocking glass of the present invention has a visible light transmittance higher than the visible light transmittance of the glass substrate, and a solar heat absorption lower than the solar heat absorption of the glass substrate. The radiant heat absorptance of the glass substrate in the wavelength region of room temperature heat radiation is smaller than that of the glass substrate in the wavelength region of room temperature heat radiation It is. Preferably, the visible light transmittance is 90% or more, the solar heat absorptivity is 0.01 to 11%, and the radiant heat absorptivity in the wavelength range of room temperature heat radiation is 0.01 to 20%. You. More preferably, the visible light transmittance is at least 92%, the solar radiation absorptivity is 0.09 to 11%, and the radiant heat absorptivity in the wavelength range of room temperature heat radiation is 0.48 to 17%. is there.

 If the visible light transmittance is smaller than the above range, a highly transparent solar heat shielding glass cannot be obtained. Further, if the solar heat absorption rate and the radiant heat absorption rate are higher than the above ranges, it is not possible to efficiently block heat radiation to the inside of the enclosed space, and the effect of the present invention to reduce the internal heat load is not sufficient. Not demonstrated. ,

② Coating material

 In general, materials such as metals and ceramics with high reflectivity reflect in the visible light band and the wavelength range of room temperature heat radiation in the same way, so the reflection in the wavelength range of room temperature heat radiation is increased to increase the radiant heat absorption rate. If the value is reduced, the reflectance increases in the visible light band, and the transparency decreases. However, in general, gray bodies such as plastics are substances that have a high transmittance in the visible light band and a wavelength range for room-temperature heat radiation and have a low absorption rate.

 And according to Lambert-Beer's law, the thinner the material, the higher the transmittance. In other words, if a thin gray body such as plastics is formed and coated so as to increase the transmittance in the wavelength region for room temperature heat radiation and reduce the absorptance, the visible light transmittance of the coating also increases. Therefore, even if a thin gray coating such as plastic is formed on one side of the glass, the transmittance of the glass in the visible light band is hardly reduced, and the original transparency of the glass is not impaired.

 If the thin film surface is placed toward a closed space, that is, toward the inside (room or inside) of a building or vehicle, the transparency is high and the heat absorbed by the glass is not incident on the inside, A large amount of water is radiated to the outside air to reduce the heat load inside the solar cell.

As described above, as the material of the coating of the present invention, it is preferable to use a substance having a large visible light transmittance and a small radiant heat absorption in the wavelength region of solar heat absorption and room temperature heat radiation. Accordingly, the material of the coating is not particularly limited as long as the above conditions are satisfied, but is preferably plastics, for example, polyethylene, polypropylene, polyisobutylene, polystyrene, polyvinylinoleate, ethylene'butyl acetate copolymer, and polybutylene. Alcohol, polyvinyl chloride, vinyl chloride; vinylidene chloride copolymer, polyacrylonitrile, polyvinylpyrrolidone, polyacrylic acid, methyl polymethacrylate, methyl methacrylate Styrene copolymer, polybutyl methacrylate, silicone resin, butadiene rubber , Butyl rubber, chloroprene rubber, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, cellulose acetate mouth, diaryl phthalate resin, urea resin, melamine resin, polybutyl Chillal, vinyl chloride copolymer; vinyl acetate copolymer, ethylene; olefin copolymer; ethylene; vinyl chloride copolymer; atalylic acid; vinyl chloride copolymer; polymethylpentene; polytetrafluoroethylene; Polyethylene trifluoroethylene, polyvinylpyrrolidone, polymethyl methacrylate, methyl methacrylate 'styrene copolymer, polybutyl methacrylate, nylon 66, epoxy resin, butadiene. Styrene resin, polysulfone, polyvinylidene fluoride, MBS Examples include various substances such as resin, polybutadiene, and polyether sulfone, and mixtures thereof.

 Among these, more preferred are styrene resin (polystyrene), polyvinyl alcohol, acrylic resin (polyacrylic acid), silicone resin (silicone resin), polymethyl methacrylate, methyl methacrylate and ethyl acrylate. Copolymers, methyl methacrylate ′ styrene copolymer, polymethyl butyl methacrylate and the like can be mentioned. More preferred are styrene resin, acrylic resin, silicone resin, methyl methacrylate 'ethyl acrylate' styrene copolymer and the like. Particularly preferred are a styrene resin, an acrylic resin, and a silicone resin.

The method of forming a film having a predetermined visible light transmittance, solar heat absorption rate and radiant heat absorption rate using such a coating material is not particularly limited. A solution having a desired concentration can be prepared to obtain a desired coating. Preferred solvents used here include ethyl acetate, toluene, xylene, acetone, thinner and the like. In order to obtain a predetermined film using these solvents, the concentration is preferably about 0.01 to 10%.

 ③ Coating thickness

 Although the thickness of the coating of the present invention is not particularly limited, according to Lambert-Beer's law, the heat absorption increases as the thickness of the light absorbing material increases, and the heat absorption decreases as the thickness decreases. In the present invention, too, the heat absorption is reduced by reducing the thickness of the coating to some extent, the visible light transmittance is increased, and the radiant heat absorption in the wavelength range of solar radiation absorption and room temperature radiation is also used in the present invention. The rate can be reduced.

 Therefore, the lower limit of the thickness of the coating of the present invention is preferably 0.1 μππι, more preferably 0.02 μπι, further preferably 0.04 μm, and particularly preferably 0.1 μππι. And the upper limit is 10 πι, more preferably 5 μm. If the coating is too thick, not only does the visible light transmittance decrease, but the heat absorption increases, and the solar heat absorption and the radiant heat absorption tend to increase. On the other hand, if the thickness of the coating is too thin, peeling from the glass substrate may easily occur.

 ④Measurement method of radiant heat absorption rate

 The measurement method of the radiant heat absorptivity in the wavelength region of room temperature heat radiation of the coating film of the solar heat shielding glass of the present invention is shown.

 A film is formed on an aluminum plate using an infrared spectrophotometer for general chemical analysis in accordance with the measurement in the JIS-R-3106 ambient temperature radiation range. The reflectance was measured using the standard reflectance value of 310. Then, based on the fact that the relational expression + + = 1 holds between the absorptance of the gray body and the reflectance p and the transmittance τ, the absorptance is defined as “absorptivity = 1 (reflectivity ρ + Transmittance). As for the transmittance, the reflectance of the aluminum plate and the reflectance when the film was formed on the aluminum plate were obtained, and the difference was defined as the transmittance of the film.

Also, the radiant heat absorption of the coating when formed on the aluminum plate occurs twice when the radiant heat enters and when the radiant heat is reflected, so the absorptance was set to 1 Z 2 of the measured value . Using this value as the theoretical value, the glass surface and polyester fill The radiant heat absorptance in the wavelength region of room temperature heat radiation of the film formed on the surface of the film. In addition, a value calculated assuming 0 as the reflection generated on the surface of the coating film was used.

 Visible light transmittance and solar heat absorptivity were measured with a coating formed on glass and glass according to JIS-R-3106, and the difference was taken as the visible light transmittance and solar heat absorptivity of the coating. .

(3) Solar heat shielding glass

 Next, the solar heat shielding glass of the present invention will be described with reference to the accompanying drawings.

 FIG. 1 is a cross-sectional view showing the structure of an example of the solar heat shielding glass of the present invention. The visible light transmittance of one side of the glass substrate 1 is larger than that of the glass substrate (preferably 90% or more, More preferably 92% or more, and both the solar heat absorption coefficient and the radiant heat absorption coefficient in the wavelength range of room temperature heat radiation are smaller than those of the glass substrate (preferably, the solar heat absorption coefficient is 0.01 to 11). % And a radiant heat absorption coefficient in the wavelength range of room temperature heat radiation of 0.01 to 20%). In Fig. 1, A is the side to which solar heat is applied, and B is the inside of the enclosed space.

 There is no particular limitation on the shape of the solar radiation shielding glass of the present invention, and it can be formed in any shape such as a square, a circle, a tube, a hemisphere, and a sphere, and also has a corrugated surface, a convex M surface, and a protruding shape. Glass added to the surface shape such as the surface may be used.

 As a method for producing a solar heat shielding glass of the present invention by forming a coating on a glass substrate, the above-mentioned coating material is formed in advance into a film or a sheet, and the resulting material is heat-sealed and bonded, adhered, or the like. Arbitrarily selectable from the methods commonly used for laminating other materials, such as the method of sticking, the method of dissolving the coating material in an appropriate solvent, applying by a method that has been neglected, drying and solidifying can do. Further, after the coating material is treated by a conventionally used method such as dispersing or dissolving, it can be coated using the same method as described above.

Note that the example of the solar radiation blocking glass shown in FIG. 1 is an example in which the glass substrate and the coating are each a single layer, but in the present invention, one or both of the glass substrate and the coating are further configured in multiple layers. It can also be a composite. In this case, the visible light transmittance of the layer (the innermost layer) of the coating layer that is in contact with the air layer inside the enclosed space Is larger than that of the glass substrate (preferably 90% or more), and both the solar heat absorption rate and the radiant heat absorption rate in the wavelength region of room temperature heat radiation are smaller than those of the glass substrate (preferably, the solar heat absorption rate is lower than that of the glass substrate). It is preferable to form the coating so as to have a radiant heat absorption rate of 0.01 to 2% in the wavelength range of room temperature heat radiation. The solar radiation shielding glass of the present invention can be used as a window glass of a building, a building, a vehicle, or the like, and a coating can be formed later on a window glass of a conventional building, a building, a vehicle, or the like. Further, the solar radiation blocking glass of the present invention can be used in combination with conventional heat absorbing glass and heat reflecting glass.

 Specifically, such a solar heat shielding glass of the present invention can be effectively used as a window glass or a glass building material for houses, insulated warehouses, ceilings, walls, vehicles, various containers, and the like.

 In order to reduce the heat radiation from the high temperature glass, it is possible to reduce the radiant heat absorption rate by coating the glass surface with a metal or ceramic with high reflectivity and low absorption rate. Products with the above technology can reduce the radiation from the glass, which has become hotter, but it also reflects visible light and darkens the interior. If the metal layer with high reflectivity is placed on the outside air side, much of the heat absorbed by the glass will enter the inside and the internal heat load will increase. When the metal layer is arranged at the center of the multilayer system, the low radiation surface is not arranged inside the enclosed space, so that the heat load of the part (2) is not reduced, and the effect of the present invention cannot be obtained. In other words, as in the present invention, by forming a coating of plastics or the like having a low radiant heat absorption rate on the inside of a window glass of a building or a vehicle, the temperature of the glass can be increased without impairing the original transparency of visible light. There is no solar heat-shielding glass that blocks only room-temperature heat radiation from burned glass and reduces the heat load caused by solar radiation in a room or in a car.

2. How to cut off solar radiation

In the solar radiation blocking method of the present invention, the above-mentioned solar radiation blocking glass of the present invention is disposed (absorbing the radiation heat) by arranging the glass substrate surface so as to face the side irradiated with the solar radiation. This method is characterized in that heat radiation from the film surface side is cut off. That is, solar radiation heat The visible light transmittance of the blocking glass is higher than that of the glass substrate (preferably 90% or more), and both the solar heat absorption rate and the radiant heat absorption rate in the wavelength range of room temperature heat radiation are lower than those of the glass substrate. (Preferably, the solar heat absorption rate is 0.01 to 11%, and the radiant heat absorption rate in the normal temperature radiation wavelength range is 0.01 to 20%.) To the inside of the enclosed space. As a result, it is possible to effectively block heat radiation from the glass, which has been heated to a high temperature by absorbing solar radiation, to the inside without darkening the inside.

 In addition, by forming the above coating on the side surface of the inside of a closed space such as a room or the interior of a window glass of a conventional structure, building, or vehicle, the room temperature heat from the high-temperature glass can be obtained. It can block radiation and reduce the heat load caused by solar radiation in the room or in the car. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a sectional view showing the structure of the solar radiation shielding glass of the present invention. FIG. 2 is a graph showing a temperature change with time in a room in Example 3 of the present invention.

 In FIG. 1, 1 is a glass substrate, 2 is a coating, A is a side irradiated with solar heat, and B is a closed space. In FIG. 2, a indicates sample 1, b indicates sample 2, and c indicates sample 3. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. Example

Methacrylic acid Mechiruakuriru acid E Chiru styrene copolymer was diluted Ri by the acetate Echiru different concentrated solutions (each concentration;... Sample 1 = 0 1 wt / _0, sample 2 = 5 0% by weight,試科3 = 5.0% by weight, Sample 4 = 5.0% by weight, Sample 5 = 10.0% by weight, Sample 6 = 15.0% by weight). The solar heat absorptance and the radiant heat absorptivity in the wavelength range of room temperature heat radiation of each sample were adjusted by prescribing the colorant and the infrared absorber for each sample as shown below. Sample 1 and 2 = Colorant

Sample 3 = Add colorant (total solution concentration: 0.001% by weight)

Sample 4 = colorant and infrared absorber added (total solution concentration: colorant: 0.0002% by weight, infrared absorber; 0.0005 weight /.)

Sample 5 = colorant and infrared absorber added (total solution concentration: colorant; 0.001% by weight, infrared absorber; 0.001% by weight)

Sample 6 = Add colorant and infrared absorber (total solution concentration: colorant; 0.01% by weight, infrared absorber; 0.01% by weight) where "RED BW" is used as the colorant A mixed solution of 0.01% by weight (manufactured by Nippon Kayaku Co., Ltd.) and 0.01% by weight ("Ultra Sky SEJ (manufactured by Nippon Kayaku Co., Ltd.)" in ethyl acetate was used. As the infrared absorbing agent, a 1.0% by weight solution of “Evolite 2057” (solvent; a mixed solvent of MEK, IPA, ethyl acetate, and toluene) was used.

 This solution was applied to one side of the same glass plate measuring 50 cm in length and 50 cm in width using a flow coating method to form a coating. At this time, the theoretical value shown above was used as the value of the absorption in the wavelength region of the normal temperature heat radiation. Here, the thickness of the glass plate is 5 mm. The thickness of the coating was as follows: sample 1 = 0.04 μm, sample 2 = 3.2 m, sample 3 = 3.7 μπι, sample 4 = 3.9 μπι, sample 5 = 5.5 μπι, sample 6 = 8.9 μm.

The thickness of the coating was measured by the following method. When the liquid material of each sample (for example, 0.1% by weight of a sample solution 1) was applied to the above glass plate (0.5m x 0.50.5m x 0.25m ² ) by flowing coating, it flowed down. The weight of the solution was measured and the weight of the reduced solution was attached to the glass.The weight of the solid was calculated, and the weight of the solid was divided by the area of the glass. It was used as a value. The same applies to other samples.

Then create 5 mm thick of styrofoam plates ^Te? Cube that is open only one side box (5 0 X 5 0 X 5 O cm) 7 pieces of, uncoated in the opening of the box glass plate及And the coated glass plate was placed and attached so that the coated surface was on the middle side. Place in a room set at 20 ° C with the coated and uncoated glass plates facing up, with the opening facing upwards, from 50 cm above the glass to 60 W—with an infrared lamp. Heating was performed until the temperature in the box became equilibrium, and the temperature in the box at that time was measured. Table 1 shows the results.

 * 1) Solar heat absorption, radiant heat absorption, and visible light transmittance of the glass plate As is clear from the results of samples 1 to 3 (Example), the equilibrium temperature in the box when heated by an infrared lamp is When both the solar heat absorptivity and the radiant heat absorptivity in the wavelength range of room temperature heat radiation are smaller than the case of only a glass plate, the temperature becomes lower by 0.2 to 1.7 ° C than that of glass, and it is heated by an infrared lamp to a high temperature. It can be seen that the radiant heat from the lost glass surface has decreased. The visible light transmittance of the coating at this time is 94.2 to 99.8%, and the visible light transmittance of the glass on which the coating is formed is 85% or more. It turns out that it does not reduce.

On the other hand, in the case of samples 4 to 6 (comparative example), the radiant heat absorption rate of the coating in the wavelength region of room temperature heat radiation is smaller than that of the glass plate, but the solar heat absorption rate is larger than that of the glass plate. When the solar heat absorption rate of the coating is greater than that of glass, the solar heat transmitted through the glass When the heat is dissipated to the outside air, most of the heat absorbed by the coating enters the box when the heat is dissipated to the outside air.

 Usually, the heat absorbed by the glass is the heat that enters the enclosed space and the heat that is released to the outside air. The temperature inside the enclosed space (inside the box) absorbs the heat that passes through the glass and directly enters the interior and the solar heat. It is determined by the total heat entering from the hotter glass. In the case of samples 4 to 6, the amount of heat that penetrates directly into the glass through the glass decreases, but the heat absorbed by the film is disturbed by the glass and is hardly radiated to the outside air, and most of the heat absorbed by the film Because it entered the box, the sum of the heat entering the box from the glass and the coating that became high due to the heat that entered directly through the glass and the solar heat absorbed through the glass increased, and the temperature inside the box was higher than when only the glass was used. It is thought that it became higher. In other words, in samples 4 to 6 where the solar heat absorption of the coating is larger than that of the glass plate, the temperature inside the box was higher than that of the case where only glass was used, even if the radiant heat absorption in the wavelength range of room temperature heat radiation was smaller than that of glass Things. Example 2

 A 5 mm thick styrofoam box (50 × 50 × 5 × 5 mm) in which an uncoated glass plate and a coated glass plate similar to those used in Example 1 were arranged so that the coated surface was on the middle side. 0 cm).

With the opening with the coated and uncoated glass plates facing upwards, place it in a wide area where the sunlight shines well. The temperature was measured. The theoretical values of the visible light transmittance, the solar heat absorptivity, and the absorptance in the wavelength region of room temperature heat radiation of the coating film were the same as in Example 1. The outside temperature at this time was 34.6 ° C. Table 2 shows the results.

Table 2

* 1) Solar heat absorptance, radiant heat absorptivity, and visible light transmittance of the glass plate From the results of Samples 1 to 3 (Examples), the maximum temperature in the box when irradiating sunlight is the solar heat of the coating. When both the absorptance and the absorptivity in the wavelength range of room temperature heat radiation were smaller than the glass plate, the temperature was lower by 0.1 to 2.5 ° C than that of the case with glass alone, and it was attached to the opening of a styrofoam box. It can be seen that the radiant heat from the inner surface of the glass decreased and much heat was radiated to the outside. At this time, the visible light transmittance of the coating is 94.2 to 99.8%, and the visible light transmittance of the glass on which the coating is formed is 85% or more. You can see that it will not be done. On the other hand, in the case of samples 4 to 6 (comparative example), the radiant heat absorptivity of the coating in the wavelength region of room temperature heat radiation is smaller than the glass plate, and the solar heat absorptivity is larger than the glass plate. Although the heat input decreased, the heat absorbed by the coating was disturbed by the glass and hardly radiated to the outside air, and most of the heat absorbed by the coating entered the box, so the heat directly transmitted through the glass and entered. It is probable that the total amount of heat entering the box from the glass and the coating, which became hot due to the absorption of solar heat, increased, and the temperature inside the box became higher than in the case of glass alone. Example 3

In 8 floor of the building of reinforced concrete 9-story, volume shall apply in 55m ^3, vertical 1. 5 m which fit the window glass having a thickness of 5mm eastward wall, horizontal 2. rectangles of 8 m Prepare three identical rooms with windows next to each other, and on the indoor side of the window glass, the glass window of one room has the solar heat absorption rate created in Example 1 0.09% and the wavelength of room temperature radiation A paint with a radiant heat absorption coefficient (theoretical value) of 0.48% in the region was applied using a flow coating method to form a coating (thickness: 0.04 / m) (Sample 1). The window glass of the other room is a polyester film provided with an adhesive layer on the side to be attached to the glass, and has a solar heat absorption coefficient of 0 on the side opposite to the adhesive layer, similarly to the above. It is coated with a liquid that has an absorption rate (theoretical value) of 0.48% in the wavelength range of room temperature heat radiation at 09% (thickness of coating layer: 0.07 μπι, thickness of film: 50 m, The thickness of the adhesive layer: 20 m) was stuck on the indoor side (Sample 2). The other room had only window glass (Sample 3).

 In the room where the film was formed on the window glass (Sample 1), the room where the polyester film was stuck (Sample 2), and the room with only the window glass (Sample 3), 1 m from the window in the room when the sunlight was irradiated. The temperature change over time at a remote point was measured. The theoretical values of the solar heat absorption rate and the radiant heat absorption rate of the coating were the same as in Example 1. Table 3 shows the results. The unit of the numerical value in the table is. C.

 Table 3

試料 1と試料 2の両方とも太陽光線が照射した 7 : 00の時点での試料 3との 温度差 3. 3〜3. 5°Cとなり、 被膜の常温熱放射の波長域における放射熱吸収 率が小さくなり、 ガラスの中側表面から室内べの放射熱伝達が減少し、 外部へ多 く放熱したことが分かる。 室内の経時的な温度変化のグラフを図 2に表す。 実施例 4

Both Sample 1 and Sample 2 had a temperature difference of 3.3 to 3.5 ° C from Sample 3 at the time of 7:00 when sunlight was irradiated at 7:00, and the radiant heat absorptance in the wavelength range of room temperature thermal radiation of the coating Radiant heat transfer from the inside surface of the glass to the inside of the room decreases, It can be seen that heat was dissipated. Figure 2 shows a graph of the temperature change over time in the room. Example 4

 Seven cubic boxes (50 × 50 × 50 cm) each having only one side opened with a 5 mm thick styrofoam plate used in Example 1 were prepared and prepared.

 The same paint as that used in Example 1 was applied to the surface of the polyester film having an adhesive layer of 25 tm on the side opposite to the adhesive layer having a thickness of 50 <um by a flow coating method, and the film was coated. Formed.

 This film was adhered to a glass plate with a thickness of 5 mm via an adhesive layer (a polyester film with only an uncoated film was also prepared) so that the film-forming surface of the film was on the inside of the box. Was placed. The glass surface was set up in a wide place where the sunlight could well hit, and the temperature when the inside of the box was equilibrated when the sunlight was irradiated was measured. The outside temperature at this time was 34.9 ° C. As in Example 1, theoretical values were used for the solar radiation absorptance of the coating and the radiant heat absorptance in the wavelength region of room temperature thermal radiation. The results are shown in Table 4.

 Table 4

* 1) Solar heat absorption rate of glass plate with only polyester film Radiant heat absorptivity and visible light transmission The maximum temperature in the box when illuminated with sunlight is the same as that of a glass plate on which only the polyester film is applied, both the solar heat absorptance of the coating and the absorptivity in the normal temperature heat radiation wavelength range. When it is smaller, the maximum temperature of the box is 0.1 to 2.0 ° C lower than that of a glass plate with only a polyester film attached, and the inside of the glass attached to the opening of the styrofoam box It can be seen that the radiant heat from the surface decreased and much heat was radiated to the outside.

On the other hand, the radiant heat absorptivity of the coating in the wavelength range of room temperature heat radiation is smaller than that of the glass plate with only the polyester film, but the solar heat absorption is larger than that of the glass plate with only the polyester film. In the case of (Comparative Example), the amount of heat that penetrates directly into the glass through the glass decreased, but the heat absorbed by the film was hindered by the glass and hardly radiated to the outside air, and most of the heat absorbed by the film Entered the box, the sum of the heat directly entering through the glass and the heat that absorbed the solar radiation and entering the box from the high-temperature glass and the coating increases the temperature inside the box compared to the case of glass alone. ₀ Example 5

 Seven cubic boxes (50 × 50 × 50 cm) each having only one side opened with a 5 mm thick styrofoam plate used in Example 1 were prepared and prepared.

 Then, the paint prepared in Example 1 was applied to a heat ray absorbing glass having a solar heat absorption rate of 33.6% in the same manner as in Example 1.

Next, as in Example 1, the heat-absorbing glass was placed on the box such that the coating surface was on the inside of the box, and the glass face was placed upward. Then, it was installed in a wide area where the sunlight shines well, and the temperature was measured when the inside of the box when the sunlight was irradiated became equilibrium. The outside temperature at this time was 33.2 ° C. Table 5 shows the results. Table 5

 * 1) Solar heat absorption rate, radiant heat absorption rate, and visible light transmittance of the heat-absorbing glass plate The equilibrium temperature in a closed box when irradiated with sunlight is 0.09 When the absorptance of the coating in the wavelength range of room temperature heat radiation is 0.48 to 16.9% and the maximum temperature in the closed box is 1.2% than that of the heat ray absorbing glass alone, 66.1 ° C. lower, indicating that the heat ray absorbing glass is also effective. Industrial applicability

 The solar radiation blocking glass of the present invention is obtained by forming a coating on one surface of a glass substrate having a large transmittance in the visible light band and a small absorption rate in the solar heat absorption and in the wavelength range of room temperature heat radiation. By installing the glass window made of this solar radiation blocking glass so that the coating surface faces the inside of a closed space such as a building or vehicle (inside or inside the vehicle), the glass surface was heated by the solar radiation and the temperature rose. The heat radiation from the glass, which is generated later, is prevented from entering the inside, so that a large amount of heat is radiated to the outside air side, and the heat load in the room or the like can be reduced.

 In addition, since the inherent transparency of visible light is not impaired by glass, the temperature inside can be suppressed from rising without darkening the interior of the room or the interior of the vehicle. Furthermore, unlike conventional products using metals and ceramics, they can be manufactured easily and inexpensively. Therefore, it can be effectively used as window glass and glass building materials for houses, insulated warehouses, ceilings, walls, vehicles, and various containers.

Claims

The scope of the claims 1. On one side of the glass substrate, the visible light transmittance is larger than the visible light transmittance of the glass substrate, and both the solar heat absorption and the radiant heat absorption in the wavelength range of room temperature heat radiation are the solar heat absorption of the glass substrate. A solar heat shielding glass characterized in that it has a coating having a smaller coefficient of radiation and a radiant heat absorption coefficient in a wavelength range of room temperature heat radiation. 2. The coating has a visible light transmittance of 90% or more, a solar heat absorption of 0.01 to 11%, and a radiant heat absorption in the wavelength range of room temperature heat radiation of 0.01 to 20%. The solar heat shielding glass according to claim 1, wherein 3. The solar heat shielding glass according to claim 1 or 2, wherein a wavelength range of room temperature heat radiation in the radiant heat absorption rate is 5 to 50 µm. 4. The solar heat shielding glass according to any one of claims 1 to 3, wherein the material forming the film is a plastic selected from the group consisting of an acrylic resin, a silicone resin, and a styrene resin. 5. The solar heat shielding glass according to any one of claims 1 to 4, wherein the coating has a thickness of 0.01 to 10 μπι. 6. The solar heat shielding glass according to any one of claims 1 to 4, wherein the glass substrate surface is disposed so as to face a side to which the solar heat is applied, and heat radiation from the coating surface side is blocked. A method for shutting off solar radiation.