Solar radiation shielding material, solar radiation shielding material dispersion, solar radiation shielding transparent substrate

Abstract

To provide a sunshine blocking material that has sufficient transparency to allow the passage of visible light and also has a high capability of blocking near-infrared rays.SOLUTION: A sunshine blocking material contains a hexaboride containing at least one element R selected from rare earth elements, and boron, the hexaboride having a valence x of 0<x<0.3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a solar radiation shielding material, a solar radiation shielding material dispersion, and a solar radiation shielding transparent substrate.

Background Art

[0002] Windows of automobiles and the like are required to sufficiently transmit visible light and shield near-infrared light called heat rays.

[0003] Therefore, a method of incorporating a solar radiation shielding material capable of shielding near-infrared light into glass, resin, etc. used for windows is used. For example, Patent Document 1 proposes a heat ray shielding material containing boride fine particles.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Among boride particles, hexaboride particles are a promising solar radiation shielding material having both high near-infrared light shielding characteristics and visible light transparency (visible light transmittance), and are widely used industrially.

[0006] However, hexaboride particles have a problem that since the absorption of near-infrared light partially covers the high wavelength side of visible light, the red component of visible light does not transmit.

[0007] Therefore, in view of the problems of the above prior art, an object of one aspect of the present invention is to provide a solar radiation shielding material having high visible light transparency and excellent near-infrared light shielding characteristics.

Means for Solving the Problems

[0008] According to one aspect of the present invention, in order to solve the above problems, it contains a hexaboride containing one or more elements R selected from rare earth elements and boron, and the valence number x of the hexaboride satisfies 0 < x < 0.3 , The hexaboride is represented by (R 1-a A1 a )(B 6-b A2 b ), where A1 is one or more selected from Sr and Ba, A2 is a substitution element or a vacancy, a satisfies 0 ≦ a < 1, and b satisfies 0 ≦ b < 6 a solar radiation shielding material is provided.

Effect of the Invention

[0009] According to one aspect of the present invention, a solar radiation shielding material with high visible light transparency and excellent near-infrared light shielding characteristics can be provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0011] Hereinafter, the modes for carrying out the present invention will be described. However, the present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention. [Solar Radiation Shielding Material] The solar radiation shielding material of the present embodiment will be described.

[0012] The solar radiation shielding material of this embodiment can contain a hexaboride containing at least one element R selected from rare earth elements and boron. And the valence number x of the hexaboride can be set to 0 < x < 0.3. Note that the solar radiation shielding material of this embodiment may be composed only of the above hexaboride, but in this case, it does not exclude containing inevitable impurities.

[0013] In order to obtain a hexaboride with high visible light transparency and excellent near-infrared light shielding performance, the inventor of the present invention calculated the optical properties of each compound on a computer and conducted a search.

[0014] Specifically, for hexaborides and their substitutes, a search was conducted by calculating and comparing their optical properties.

[0015] The optical properties were obtained by first-principles calculation of the bulk dielectric function, and the absorption efficiency in the case of a sphere with a radius of 20 nm was estimated and calculated by the Mie scattering theory.

[0016] As a result, it was found that by reducing the free electrons of the hexaboride containing at least one element R selected from rare earth elements and boron, a solar radiation shielding material with high visible light transparency and excellent near-infrared light shielding characteristics can be obtained.

[0017] By reducing the free electrons of the hexaboride, the absorption of visible light by the free electrons is reduced, and the transmission performance on the low-energy side in the visible light region is improved, so the transparency of red color is improved. Also, almost no new absorption peaks appear in the visible light region and the near-infrared region. Therefore, according to the solar radiation shielding material of this embodiment, it is possible to achieve both high visible light transparency and high absorption performance of near-infrared light at a high level.

[0018] When the valence number x of the above hexaboride becomes too large, the light absorption performance in the near-infrared region by free electrons is lost, so the range of 0 < x < 0.3 is preferable.

[0019] The above hexaboride is, for example, (RB 6 ) +xIt can be expressed as follows, where R represents the element R and B represents boron. As will be described later, for example, a part of the element R or boron can be replaced by a substitution element, a vacancy, etc., so the molar ratio of the element R to boron may deviate from 1:6. Therefore, the above hexaboride can be a material having an electronic structure similar to (RB 6 ) +x , or a material that can formally be expressed as the above notation. Note that +x in the above formula means the valence of the hexaboride.

[0020] As a method for reducing the free electrons of the hexaboride, for example, in addition to the method of replacing the element R or boron contained in the hexaboride with an element having a small number of electrons, there is a method of dispersing it in a reducing solution.

[0021] Therefore, the hexaboride contained in the solar radiation shielding material of this embodiment can be expressed, for example, as (R 1-a A1 a )(B 6-b A2 b ). In the above formula, A1 and A2 are each a substitution element or a vacancy, and a satisfies 0 ≦ a < 1, and b satisfies 0 ≦ b < 6. It is preferable that b is, for example, 0 ≦ b < 2. The valence x of the hexaboride (R 1-a A1 a )(B 6-b A2 b ) is 0 < x < 0.3, that is, greater than 0 and less than +0.3. Therefore, it may be expressed as (R 1-a A1 a )(B 6-b A2 b ) +x as follows.

[0022] A1 and A2 are not particularly limited and can be substitution elements or vacancies as described above. Examples of A1 include one or more selected from Sr and Ba, and examples of A2 include one or more selected from Be and Mg.

[0023] The element R of the hexaboride is preferably La. This is because when La is used as the element R, the absorption characteristics of near-infrared rays are particularly enhanced.

[0024] The manufacturing method of the solar radiation shielding material of this embodiment is not particularly limited. For example, a method of firing a mixture of RB before substitution 6 and a compound containing A1 or A2 as a substitution element, a method of firing RB before substitution 6 in a reducing atmosphere, a method of dispersing it in a reducing solution, etc. can be mentioned.

[0025] For example, when the element R is La and A1 is Ca, a compound containing La, a compound containing B, and a compound containing Ca can be mixed to prepare a raw material mixture. Examples of the compound containing La include La 2 O 3 etc. Examples of the compound containing B include B 4 C etc. Examples of the compound containing Ca include CaO etc. Note that the raw material mixture can contain each raw material in a ratio according to the target composition.

[0026] Then, the obtained raw material mixture is formed into pellets or the like as necessary and fired to obtain a hexaboride. The firing conditions are not particularly limited, but for example, it can be fired at a temperature of about 2100 °C in a vacuum atmosphere.

[0027] Then, if necessary, the obtained fired product can be pulverized and adjusted to a desired particle size. [Solar Radiation Shielding Material Dispersion Liquid] Next, a configuration example of the solar radiation shielding material dispersion liquid of this embodiment will be described.

[0028] The solar radiation shielding material dispersion liquid of this embodiment can include the above-described solar radiation shielding material and one or more liquid media selected from water, organic solvents, oils and fats, liquid resins, and liquid plasticizers. The solar radiation shielding material dispersion liquid preferably has a configuration in which the solar radiation shielding material is dispersed in the liquid medium.

[0029] As the liquid medium, as described above, one or more selected from water, organic solvents, oils and fats, liquid resins, and liquid plasticizers can be used.

[0030] As the organic solvent, various types such as alcohol-based, ketone-based, hydrocarbon-based, glycol-based, and water-based can be selected. Specifically, alcohol-based solvents such as isopropyl alcohol, methanol, ethanol, 1-propanol, isopropanol, butanol, pentanol, benzyl alcohol, diacetone alcohol, 1-methoxy-2-propanol; ketone-based solvents such as dimethyl ketone, acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone; ester-based solvents such as 3-methyl-methoxy-propionate, butyl acetate; glycol derivatives such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol isopropyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate; amides such as formamide, N-methylformamide, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone; aromatic hydrocarbons such as toluene, xylene; halogenated hydrocarbons such as ethylene chloride, chlorobenzene, etc. One or more selected from these can be mentioned.

[0031] However, among these, organic solvents with low polarity are preferred, and in particular, isopropyl alcohol, ethanol, 1-methoxy-2-propanol, dimethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, toluene, propylene glycol monomethyl ether acetate, n-butyl acetate, etc. are more preferred. These organic solvents can be used alone or in combination of two or more.

[0032] As the oil, for example, one or more selected from drying oils such as linseed oil, sunflower oil, and tung oil, semi-drying oils such as sesame oil, cottonseed oil, rapeseed oil, soybean oil, and rice bran oil, non-drying oils such as olive oil, coconut oil, palm oil, and dehydrated castor oil, fatty acid monoesters obtained by directly subjecting fatty acids of vegetable oils and monoalcohols to an ester reaction, ethers, Isopar (registered trademark) E, Exxsol (registered trademark) Hexane, Heptane, E, D30, D40, D60, D80, D95, D110, D130 (the above are manufactured by ExxonMobil), and other petroleum solvents can be used.

[0033] As the liquid resin, for example, one or more selected from liquid acrylic resins, liquid epoxy resins, liquid polyester resins, liquid urethane resins, etc. can be used.

[0034] As the liquid plasticizer, for example, a liquid plasticizer for plastics can be used.

[0035] The components contained in the solar radiation shielding material dispersion are not limited to only the above-mentioned solar radiation shielding material and the liquid medium. The solar radiation shielding material dispersion can also contain, if necessary, further arbitrary components.

[0036] For example, an acid or an alkali can be added to the solar radiation shielding material dispersion as necessary to adjust the pH of the dispersion.

[0037] Also, in the above-mentioned solar radiation shielding material dispersion, in order to further improve the dispersion stability of the solar radiation shielding material and avoid coarsening of the dispersion particle size due to re-aggregation, various surfactants, coupling agents, etc. can be added as dispersants to the solar radiation shielding material dispersion.

[0038] Dispersants such as the surfactant and coupling agent can be selected according to the application, but it is preferable that the dispersant has at least one selected from among a group containing an amine, a hydroxyl group, a carboxyl group, and an epoxy group as a functional group. These functional groups adsorb on the surface of the sunlight-shielding material to prevent aggregation, and also have the effect of uniformly dispersing the sunlight-shielding material in the sunlight-shielding film formed using the sunlight-shielding material. A polymeric dispersant having at least one selected from the above functional groups (functional group groups) in the molecule is more desirable.

[0039] Examples of commercially available dispersants that can be suitably used include Solsperse (registered trademark) 9000, 12000, 17000, 20000, 21000, 24000, 26000, 27000, 28000, 32000, 35100, 54000, 250 (manufactured by Nippon Lubrizol Corporation), EFKA (registered trademark) 4008, 4009, 4010, 4015, 4046, 4047, 4060, 4080, 7462, 4020, 4050, 4055, 4400, 4401, 4402, 4403, 4300, 4320, 4330, 4340, 6220, 6225, 6700, 6780, 6782, 8503 (manufactured by Efka Additives), Ajisper (registered trademark) PA111, PB821, PB822, PN411, Faimax L-12 (manufactured by Ajinomoto Fine-Techno Co., Ltd.), DisperBYK (registered trademark) 101, 102, 106, 108, 111, 116, 130, 140, 142, 145, 161, 162, 163, 164, 166, 167, 168, 170, 171, 174, 180, 182, 192, 193, 2000, 2001, 2020, 2025, 2050, 2070, 2155, 2164, 220S, 300, 306, 320, 322, 325, 330, 340, 350, 377, 378, 380N, 410, 425, 430 (manufactured by BYK-Chemie Japan Co., Ltd.), Disperpon (registered trademark) 1751N, 1831, 1850, 1860, 1934, DA-400N, DA-703-50, DA-725, DA-705, DA-7301, DN-900, NS-5210, NVI-8514L (manufactured by Kusumoto Chemicals, Ltd.), Alphon (registered trademark) UC-3000, UF-5022, UG-4010, UG-4035, UG-4070 (manufactured by Toagosei Co., Ltd.), etc. One or more selected therefrom may be mentioned.

[0040] The method for dispersing the solar radiation shielding material in the liquid medium is not particularly limited as long as it can disperse the solar radiation shielding material in the liquid medium. At this time, it is preferable that the average particle size of the solar radiation shielding material can be dispersed so as to be 200 nm or less, and more preferably so as to be 0.1 nm or more and 200 nm or less.

[0041] As a method for dispersing a solar radiation shielding material in a liquid medium, for example, there are dispersion treatment methods using devices such as bead mills, ball mills, sand mills, paint shakers, and ultrasonic homogenizers. Among them, from the viewpoint of shortening the time required to obtain a desired average particle size by pulverizing and dispersing with a media agitation mill such as a bead mill, ball mill, sand mill, or paint shaker that uses media (beads, balls, Ottawa sand), it is preferable. By the pulverization-dispersion treatment using a media agitation mill, at the same time as the dispersion of the solar radiation shielding material in the liquid medium, the solar radiation shielding material is also made finer by collisions between the solar radiation shielding materials and collisions of the media with the solar radiation shielding material, and the solar radiation shielding material can be made finer and dispersed. That is, it is pulverized-dispersed.

[0042] The average particle size of the solar radiation shielding material is preferably 0.1 nm or more and 200 nm or less as described above. This is because if the average particle size is small, the scattering of light in the visible light region with a wavelength of 400 nm or more and 780 nm or less due to geometric scattering or Mie scattering is reduced. As a result, for example, a solar radiation shielding material dispersion in which the solar radiation shielding material is dispersed in a resin or the like obtained using the solar radiation shielding material dispersion liquid of the present embodiment becomes like frosted glass, and it is possible to avoid the loss of clear transparency. That is, when the average particle size becomes 200 nm or less, the mode of the above geometric scattering or Mie scattering of light scattering becomes weak, and it becomes the Rayleigh scattering mode. In the Rayleigh scattering region, since the scattered light is proportional to the sixth power of the dispersed particle size, the scattering is reduced and the transparency is improved as the dispersed particle size decreases. And when the average particle size becomes 100 nm or less, the scattered light becomes very small, which is preferable.

[0043] By the way, as long as a known method of adding the dispersion liquid to the solid medium is performed, the dispersion state of the solar radiation shielding material in the solar radiation shielding material dispersion in which the solar radiation shielding material is dispersed in a solid medium such as a resin using the solar radiation shielding material dispersion liquid of the present embodiment does not aggregate more than the average particle size of the solar radiation shielding material in the dispersion liquid.

[0044] In addition, if the average particle size of the solar radiation shielding material is 0.1 nm or more and 200 nm or less, it is possible to avoid the manufactured solar radiation shielding material dispersion and its molded body (such as a plate or sheet) from becoming a monotonous gray system with a decreasing transmittance.

[0045] The content of the solar radiation shielding material in the solar radiation shielding material dispersion liquid of the present embodiment is not particularly limited, but for example, it is preferably 0.01% by mass or more and 80% by mass or less. This is because sufficient solar radiation transmittance can be exhibited by setting the content of the solar radiation shielding material to 0.01% by mass or more. In addition, by setting it to 80% by mass or less, the solar radiation shielding material can be uniformly dispersed in the dispersion medium. [Solar radiation shielding material dispersion] Next, the solar radiation shielding material dispersion of the present embodiment will be described.

[0046] The solar radiation shielding material dispersion of the present embodiment can include a solid medium and the above-described solar radiation shielding material disposed in the solid medium. Note that the solar radiation shielding material is preferably dispersed in the solid medium.

[0047] Hereinafter, the solar radiation shielding material dispersion according to the present embodiment will be described in the order of (1) solid medium, (2) manufacturing method, (3) additive, and (4) application example. (1) Solid medium As the solid medium, one or more selected from medium resins (resins) such as thermoplastic resins, thermosetting resins, and ultraviolet curable resins, inorganic binders, and glass can be preferably used. In particular, the solid medium is more preferably a resin or glass.

[0048] The specific material of the medium resin is not particularly limited. For example, it is preferably one resin selected from the group of resins consisting of polyester resin, polycarbonate resin, acrylic resin, styrene resin, polyamide resin, polyethylene resin, vinyl chloride resin, olefin resin, epoxy resin, polyimide resin, fluororesin, ethylene-vinyl acetate copolymer, polyvinyl acetal resin, and ultraviolet curable resin, or a mixture of two or more resins selected from the above resin group. In addition, as the polyester resin, polyethylene terephthalate resin can be preferably used.

[0049] These medium resins can also contain a polymer dispersant having at least one selected from the group consisting of a group containing an amine in the main skeleton, a hydroxyl group, a carboxyl group, and an epoxy group as a functional group.

[0050] The solid medium is not limited to the medium resin, and it is also possible to use a binder using a metal alkoxide as the solid medium. Representative examples of the metal alkoxide include alkoxides of Si, Ti, Al, Zr, etc. By subjecting the binder using these metal alkoxides to hydrolysis and polycondensation by heating or the like, it is also possible to obtain a solar radiation shielding material dispersion in which the solid medium contains an oxide.

[0051] The content ratio of the solar radiation shielding material in the solar radiation shielding material dispersion according to the present embodiment is not particularly limited, but the solar radiation shielding material dispersion preferably contains 0.001% by mass or more and 80% by mass or less of the solar radiation shielding material.

[0052] The shape of the solar radiation shielding material dispersion of the present embodiment is not particularly limited, but the solar radiation shielding material dispersion of the present embodiment preferably has a sheet shape, a board shape, or a film shape. This is because the solar radiation shielding material dispersion can be applied to various uses by making it into a sheet shape, a board shape, or a film shape. (2) Manufacturing method of solar radiation shielding material dispersion The manufacturing method of the solar radiation shielding material dispersion of the present embodiment will be described below. Note that here, only a configuration example of the manufacturing method of the solar radiation shielding material dispersion is shown, and the manufacturing method of the solar radiation shielding material dispersion is not limited to the following configuration example.

[0053] The solar radiation shielding material dispersion of the present embodiment can be manufactured, for example, using a masterbatch. In this case, the manufacturing method of the solar radiation shielding material dispersion of the present embodiment can also have, for example, the following masterbatch preparation process.

[0054] A masterbatch preparation process for obtaining a masterbatch in which a solar radiation shielding material is dispersed in a solid medium.

[0055] In the masterbatch preparation process, a masterbatch in which a solar radiation shielding material is dispersed in a solid medium can be prepared.

[0056] The specific method for preparing the masterbatch is not particularly limited. For example, a masterbatch can be prepared by dispersing a solar radiation shielding material dispersion liquid or a solar radiation shielding material in a solid medium and pelletizing the solid medium.

[0057] Note that as the solar radiation shielding material, a solar radiation shielding material dispersion powder obtained by removing a liquid medium from a solar radiation shielding material dispersion liquid can also be used.

[0058] For example, a solar radiation shielding material dispersion liquid, a solar radiation shielding material, a solar radiation shielding material dispersion powder, the powder or pellets of a solid medium, and, if necessary, other additives are uniformly mixed to prepare a mixture. Then, the mixture is kneaded with a vented single-screw or twin-screw extruder and processed into pellets by cutting the melt-extruded strands. In this case, examples of the pellet shape include cylindrical and prismatic shapes. Also, when producing pellets, it is possible to adopt a so-called hot cut method of directly cutting the melt extrudate. In this case, a shape close to a spherical shape is generally obtained.

[0059] In addition, when using the solar radiation shielding material dispersion as a raw material in the masterbatch production process, it is preferable to reduce and remove the liquid medium derived from the solar radiation shielding material dispersion. In this case, the degree of removing the liquid medium contained in the solar radiation shielding material dispersion is not particularly limited. For example, it is preferable to remove the liquid medium from the solar radiation shielding material dispersion or the like until the amount remaining in the masterbatch is acceptable. In addition, when a liquid plasticizer is used as the liquid medium, the entire amount of the liquid plasticizer may remain in the solar radiation shielding material dispersion.

[0060] The method for reducing and removing the liquid medium contained in the solar radiation shielding material dispersion from the solar radiation shielding material dispersion or the mixture of the solar radiation shielding material dispersion and the solid medium is not particularly limited. For example, it is preferable to subject the solar radiation shielding material dispersion or the like to drying under reduced pressure (drying process). Specifically, the solar radiation shielding material dispersion or the like is dried under reduced pressure while being stirred to separate the solar radiation shielding material-containing composition and the components of the liquid medium. Examples of the apparatus used for the drying under reduced pressure include a vacuum stirring type dryer, but any apparatus having the above functions may be used and is not particularly limited. In addition, the pressure value during the reduced pressure in the drying process is appropriately selected.

[0061] By using the drying under reduced pressure method, the removal efficiency of the liquid medium and the like derived from the solar radiation shielding material dispersion is improved, and the solar radiation shielding material dispersion powder obtained after drying under reduced pressure and the solar radiation shielding material dispersion as the raw material are not exposed to high temperatures for a long time. Therefore, aggregation of the solar radiation shielding material dispersed in the solar radiation shielding material dispersion powder or the solar radiation shielding material dispersion does not occur, which is preferable. Furthermore, the productivity of the solar radiation shielding material dispersion powder and the like is also increased, and it is easy to recover the solvent such as the evaporated liquid medium, which is also preferable from the perspective of environmental consideration.

[0062] In the solar radiation shielding material dispersion powder obtained after the drying process, it is preferable to sufficiently remove the solvent component having a boiling point of 120°C or lower. For example, the residual amount of such a solvent component is preferably 2.5% by mass or less. If the residual solvent component is 2.5% by mass or less, when the solar radiation shielding material dispersion powder or the like is processed into a solar radiation shielding material dispersion, for example, no bubbles are generated, and the appearance and optical properties are kept good. Further, if the solvent component remaining in the solar radiation shielding material dispersion powder is 2.5% by mass or less, when the solar radiation shielding material dispersion powder is stored for a long time, aggregation due to natural drying of the remaining solvent component does not occur, and long-term stability is maintained.

[0063] The obtained masterbatch can adjust the dispersion concentration while maintaining the dispersion state of the solar radiation shielding material contained in the solar radiation shielding material dispersion by adding a solid medium and kneading.

[0064] Further, the method for producing the solar radiation shielding material dispersion of the present embodiment can have a molding step of molding, as necessary, the obtained masterbatch or the masterbatch with a solid medium added thereto into a solar radiation shielding material dispersion having a desired shape.

[0065] The specific method for molding the solar radiation shielding material dispersion is not particularly limited, and for example, known methods such as an extrusion molding method and an injection molding method can be used.

[0066] In the molding step, for example, a sheet-shaped, board-shaped, or film-shaped solar radiation shielding material dispersion molded into a planar shape or a curved surface shape can be produced. The method for molding into a sheet shape, board shape, or film shape is not particularly limited, and various known methods can be used. For example, a calendar roll method, an extrusion method, a casting method, an inflation method, or the like can be used.

[0067] The method for producing the solar radiation shielding material dispersion of the present embodiment is not limited to the form having the above masterbatch preparation step.

[0068] For example, the method for manufacturing the solar radiation shielding material dispersion of the present embodiment can also be in a form having the following steps.

[0069] A precursor liquid preparation step of preparing a precursor liquid of the solar radiation shielding material dispersion by mixing a monomer, oligomer, and uncured liquid solid medium precursor of the solid medium with a solar radiation shielding material (solar radiation shielding material dispersion powder) or a solar radiation shielding material dispersion liquid.

[0070] A solar radiation shielding material dispersion production step of curing the solid medium precursor such as the above monomer by a chemical reaction such as condensation or polymerization to produce a solar radiation shielding material dispersion.

[0071] For example, when an acrylic resin is used as the solid medium, an acrylic monomer or an acrylic ultraviolet curable resin can be mixed with a solar radiation shielding material to obtain a precursor liquid of the solar radiation shielding material dispersion.

[0072] Next, if the precursor liquid of the solar radiation shielding material dispersion is filled into a predetermined mold or the like and radical polymerization is performed, a solar radiation shielding material dispersion using an acrylic resin can be obtained.

[0073] Even when a resin that cures by crosslinking is used as the solid medium, a dispersion can be obtained by subjecting the precursor liquid of the solar radiation shielding material dispersion to a crosslinking reaction in the same manner as in the case of using the above-described acrylic resin.

[0074] (3) Additives When a medium resin is used as the solid medium, the solar radiation shielding material dispersion of the present embodiment can usually also contain known additives (additives) such as plasticizers, flame retardants, anti-coloring agents, and fillers that are added to these resins. However, as described above, the solid medium is not limited to the medium resin, and it is also possible to use a binder using a metal alkoxide or glass.

[0075] The shape of the solar radiation shielding material dispersion according to the present embodiment is not particularly limited, but as described above, for example, it can take the form of a sheet shape, a board shape, or a film shape.

[0076] When a solar radiation shielding material dispersion in the form of a sheet, board, or film is used as an intermediate layer of a transparent substrate such as laminated glass, the solid medium contained in the solar radiation shielding material dispersion may not have sufficient flexibility and adhesion to the transparent substrate as it is. In this case, it is preferable that the solar radiation shielding material dispersion contains a plasticizer. Specifically, for example, when the solid medium is a polyvinyl acetal resin and is used for the above-mentioned applications, it is preferable that the solar radiation shielding material dispersion further contains a plasticizer.

[0077] As the above-mentioned plasticizer, a substance used as a plasticizer in the solid medium used in the solar radiation shielding material dispersion of the present embodiment can be used. For example, as the plasticizer used in a solar radiation shielding material dispersion composed of a polyvinyl acetal resin, plasticizers that are compounds of a monohydric alcohol and an organic acid ester, plasticizers that are ester-based such as polyhydric alcohol organic acid ester compounds, and plasticizers that are phosphoric acid-based such as organic phosphoric acid plasticizers can be mentioned. It is preferable that any plasticizer is liquid at room temperature. Among them, plasticizers that are ester compounds synthesized from polyhydric alcohols and fatty acids are preferable. (4) Application examples The solar radiation shielding material dispersion of the present embodiment can be used in various modes, and its usage and application modes are not particularly limited. Hereinafter, as application examples of the solar radiation shielding material dispersion of the present embodiment, a solar radiation shielding transparent substrate, a solar radiation shielding intermediate film, and a solar radiation shielding laminate will be described. (4-1) Solar radiation shielding transparent substrate The solar radiation shielding transparent substrate of the present embodiment includes a transparent substrate and a solar radiation shielding layer disposed on at least one surface of the transparent substrate, and the solar radiation shielding layer can be the above-mentioned solar radiation shielding material dispersion.

[0078] The solar radiation shielding transparent substrate of the present embodiment can have a transparent substrate as described above. As the transparent substrate, for example, one or more selected from a transparent film substrate and a transparent glass substrate can be preferably used.

[0079] The film base material is not limited to the film shape, and for example, it may be in the shape of a board or a sheet. As the material of the film base material, one or more selected from polyester resins, acrylic resins, urethane resins, polycarbonate resins, polyethylene resins, ethylene vinyl acetate copolymers, vinyl chloride resins, fluororesins, etc. can be preferably used, and it can be used according to various purposes. However, as the material of the film base material, a polyester resin is preferably used, and more preferably polyethylene terephthalate resin (PET resin). That is, the film base material is preferably a polyester resin film, and more preferably a polyethylene terephthalate resin film.

[0080] When using a film base material as the transparent base material, the surface of the film base material is preferably surface-treated in order to facilitate the adhesion of the solar radiation shielding layer.

[0081] Also, in order to improve the adhesiveness between the glass base material or the film base material and the solar radiation shielding layer, it is also a preferable configuration to form an intermediate layer on the glass base material or the film base material and form a solar radiation shielding layer on the intermediate layer. The configuration of the intermediate layer is not particularly limited, and for example, it can be composed of a polymer film, a metal layer, an inorganic layer (for example, an inorganic oxide layer such as silica, titania, zirconia, etc.), an organic / inorganic composite layer, etc.

[0082] Since the solar radiation shielding material dispersion has been described above, the description is omitted here. The shape of the solar radiation shielding material dispersion is not particularly limited, but for example, it preferably has a sheet shape, a board shape, or a film shape.

[0083] The manufacturing method of the solar radiation shielding transparent base material of this embodiment will be described.

[0084] The solar radiation shielding transparent base material of this embodiment can be manufactured, for example, by using the above-described solar radiation shielding material dispersion liquid to form a solar radiation shielding layer, which is a solar radiation shielding material dispersion in which the solar radiation shielding material is dispersed in a solid medium, on the transparent base material.

[0085] Therefore, the manufacturing method of the solar radiation shielding transparent substrate of the present embodiment can include, for example, the following steps.

[0086] A coating step of coating a coating liquid containing the above-described solar radiation shielding material dispersion liquid on the surface of the transparent substrate.

[0087] After evaporating the liquid medium in the coating liquid, a solar radiation shielding layer forming step of forming a solar radiation shielding layer.

[0088] The coating liquid used in the coating step can be prepared, for example, by adding and mixing a resin, a solid medium such as a metal alkoxide, or a solid medium precursor to the above-described solar radiation shielding material dispersion liquid.

[0089] The solid medium precursor means one or more selected from the monomers, oligomers, and uncured solid media of the solid medium as described above.

[0090] When a solar radiation shielding layer, which is a coating film, is formed on the transparent substrate, the solar radiation shielding layer is in a state where the solar radiation shielding material is dispersed in the solid medium. Therefore, such a solar radiation shielding layer becomes a solar radiation shielding material dispersion. In this way, a solar radiation shielding transparent substrate can be produced by providing a solar radiation shielding material dispersion on the surface of the transparent substrate.

[0091] Since the solid medium and the solid medium precursor have been described in (1) the solar radiation shielding material dispersion and (2) the manufacturing method of the solar radiation shielding material dispersion, the description thereof is omitted here.

[0092] In order to provide a solar radiation shielding layer on the transparent substrate, the method of coating the coating liquid on the transparent substrate may be any method that can uniformly coat the coating liquid on the surface of the transparent substrate, and is not particularly limited. For example, a bar coating method, a gravure coating method, a spray coating method, a dip coating method, a spin coating method, screen printing, a roll coating method, a flow coating method, etc. can be mentioned.

[0093] Here, taking the case where an ultraviolet curable resin is used as the medium resin, and the bar coating method is used for coating to form a solar radiation shielding layer as an example, the manufacturing procedure of the solar radiation shielding layer on the surface of the transparent substrate will be described.

[0094] The coating solution with appropriately adjusted concentration and additives to have appropriate leveling property is applied onto the transparent substrate using a wire bar with a bar number that can satisfy the thickness of the solar radiation shielding layer and the content of the solar radiation shielding material for the intended purpose. Then, after removing solvents such as the liquid medium contained in the coating solution by drying, the coating layer, which is the solar radiation shielding layer, can be formed on the transparent substrate by irradiating with ultraviolet rays to cure it.

[0095] The drying conditions of the coating film vary depending on each component, the type and usage ratio of the solvent, but usually it is at a temperature of 60°C or higher and 140°C or lower for about 20 seconds or more and 10 minutes or less. There is no particular limitation on the irradiation of ultraviolet rays, and for example, an ultraviolet exposure machine such as an ultra-high pressure mercury lamp can be preferably used.

[0096] In addition, depending on the pre- and post-processes (pre-process, post-process) of the formation of the solar radiation shielding layer, the adhesion between the substrate and the solar radiation shielding layer, the smoothness of the coating film during coating, the drying property of the organic solvent, etc. can also be manipulated. Examples of the pre- and post-processes include a surface treatment process of the substrate, a pre-bake (pre-heating of the substrate) process, a post-bake (post-heating of the substrate) process, etc., and they can be appropriately selected. The heating temperature in the pre-bake process and the post-bake process is preferably, for example, 80°C or higher and 200°C or lower, and the heating time is 30 seconds or more and 240 seconds or less.

[0097] The manufacturing method of the solar radiation shielding transparent substrate of this embodiment is not limited to the above method. As another configuration example of the manufacturing method of the solar radiation shielding transparent substrate of this embodiment, a form having the following steps can also be cited.

[0098] A solar radiation shielding material dispersion liquid coating and drying step of applying the above-described solar radiation shielding material dispersion liquid onto the surface of the transparent substrate and drying it.

[0099] A binder coating and curing step of applying and curing a binder using a resin, a solid medium such as a metal alkoxide, or a solid medium precursor on the surface coated with the solar radiation shielding material dispersion.

[0100] In this case, a film in which the solar radiation shielding material is dispersed is formed on the surface of the transparent substrate by the solar radiation shielding material dispersion coating and drying step. The solar radiation shielding material dispersion can be applied by the same method as described in the coating step of the above-described method for manufacturing a solar radiation shielding transparent substrate.

[0101] Then, by applying and curing a binder on the film in which the solar radiation shielding material is dispersed, a cured binder is disposed between the solar radiation shielding materials, and a solar radiation shielding layer can be formed.

[0102] The solar radiation shielding transparent substrate can further have a coat layer on the surface of the solar radiation shielding material dispersion. That is, it can also have a multilayer film.

[0103] The coat layer can be, for example, a coating film of an oxide containing one or more selected from Si, Ti, Zr, and Al. In this case, the coat layer can be formed by, for example, applying a coating solution containing one or more selected from alkoxides containing one or more of Si, Ti, Zr, and Al and a partially hydrolyzed polycondensate of the alkoxide on the solar radiation shielding layer and then heating.

[0104] By providing the coat layer, the coated component fills the gaps where the solar radiation shielding material is deposited in the first layer to form a film and suppresses the refraction of visible light. Therefore, the haze value of the film can be further reduced and the visible light transmittance can be improved. Also, the adhesion of the solar radiation shielding material to the substrate can be improved.

[0105] Here, as a method of forming a coating film composed of an alkoxide containing one or more of Si, Ti, Zr, and Al or a partially hydrolyzed polycondensate thereof on the solar radiation shielding material alone or on a film containing the solar radiation shielding material, the coating method is preferable from the viewpoints of ease of film formation operation and cost.

[0106] As the coating liquid used in the above coating method, those containing at least one alkoxide of Si, Ti, Zr, or Al or at least one partial hydrolysis polycondensate of the alkoxide in a solvent such as water or alcohol can be preferably used. The content of the alkoxide or the like in the coating liquid is not particularly limited, but for example, it is preferably 40% by mass or less in terms of oxide in the coating obtained after heating. Also, an acid or an alkali can be added as necessary to adjust the pH.

[0107] By applying the coating liquid as a second layer onto a film mainly composed of a solar radiation shielding material and heating it, an oxide film containing at least one selected from Si, Ti, Zr, and Al, which is a coat layer, can be easily formed. It is also preferable to use an organosilazane solution as a binder component or a component of the coating liquid used in the coating liquid according to this embodiment.

[0108] As the inorganic binder or coating film, a solar radiation shielding material dispersion containing at least one metal alkoxide of Si, Ti, Zr, or Al and its hydrolysis polymer, and the substrate heating temperature after coating the coating liquid is not particularly limited. For example, the substrate heating temperature is preferably 100°C or higher, and more preferably not lower than the boiling point of the solvent in the coating liquid such as the solar radiation shielding material dispersion.

[0109] This is because when the substrate heating temperature is 100°C or higher, the polymerization reaction of the metal alkoxide or the hydrolysis polymer of the metal alkoxide contained in the coating film can be completed. Also, when the substrate heating temperature is 100°C or higher, water or an organic solvent as a solvent hardly remains in the film, so in the film after heating, these solvents do not cause a reduction in the visible light transmittance.

[0110] The thickness of the solar radiation shielding layer on the transparent substrate of the solar radiation shielding transparent substrate of the present embodiment is not particularly limited, but in practical use, it is preferably 10 μm or less, and more preferably 6 μm or less. This is because if the thickness of the solar radiation shielding layer is 10 μm or less, in addition to exhibiting sufficient pencil hardness and having scratch resistance, abnormal processes such as warping of the substrate film can be avoided during the volatilization of the solvent and the curing of the binder in the solar radiation shielding layer. (4-2) Solar radiation shielding intermediate film, solar radiation shielding laminate The solar radiation shielding laminate of the present embodiment can have a laminated structure including the above-described solar radiation shielding material dispersion and a transparent substrate. The solar radiation shielding laminate of the present embodiment can have the above-described solar radiation shielding material dispersion and a transparent substrate as elements, and can be a laminate obtained by laminating these.

[0111] Examples of the solar radiation shielding laminate include a laminate of two or more transparent substrates and the above-described solar radiation shielding material dispersion. In this case, the solar radiation shielding material dispersion can be disposed, for example, between the transparent substrates and used as a solar radiation shielding intermediate film.

[0112] In this case, the solar radiation shielding intermediate film preferably has any one of a sheet shape, a board shape, or a film shape.

[0113] As the transparent substrate, one or more selected from plate glass, plate-shaped plastic, and film-shaped plastic that are transparent in the visible light region can be preferably used.

[0114] When using plastic as the transparent substrate, the material of the plastic is not particularly limited and can be selected according to the application. For example, one or more selected from polycarbonate resin, acrylic resin, polyester resin, polyamide resin, vinyl chloride resin, olefin resin, epoxy resin, polyimide resin, ionomer resin, fluororesin, etc. can be used. As the polyester resin, polyethylene terephthalate resin can be preferably used.

[0115] The transparent substrate may contain particles having a solar radiation shielding function. As the particles having a solar radiation shielding function, a solar radiation shielding material having near-infrared ray shielding characteristics can be used.

[0116] By interposing the above-described solar radiation shielding material dispersion as a constituent member of the intermediate layer sandwiched between a plurality of transparent substrates, a solar radiation shielding laminate structure, which is a type of solar radiation shielding laminate having a near-infrared ray shielding function while transmitting visible light, can be obtained.

[0117] Note that the above-described solar radiation shielding laminate can also be obtained by sandwiching the solar radiation shielding material dispersion and bonding and integrating a plurality of transparent substrates facing each other by a known method.

[0118] When using the above-described solar radiation shielding material dispersion as a solar radiation shielding intermediate film, as the solid medium, those described for the solar radiation shielding material dispersion can be used. However, from the viewpoint of enhancing the adhesion strength between the solar radiation shielding intermediate film and the transparent substrate, the solid medium is preferably a polyvinyl acetal resin.

[0119] The solar radiation shielding intermediate film of the present embodiment can be manufactured by the manufacturing method of the above-described solar radiation shielding material dispersion, and can be a solar radiation shielding intermediate film having any one of a sheet shape, a board shape, or a film shape, for example.

[0120] Note that when the solar radiation shielding intermediate film does not sufficiently have flexibility or adhesiveness with the transparent substrate, it is preferable to add a liquid plasticizer for the medium resin. For example, when the medium resin used for the solar radiation shielding intermediate film is a polyvinyl acetal resin, the addition of a liquid plasticizer for the polyacetal resin is beneficial for improving the adhesiveness with the transparent substrate.

[0121] As the plasticizer, a substance used as a plasticizer for the base resin can be used. For example, as the plasticizer used in an infrared shielding film composed of a polyvinyl acetal resin, there are plasticizers that are compounds of a monohydric alcohol and an organic acid ester, plasticizers that are ester-based such as polyhydric alcohol organic acid ester compounds, and plasticizers that are phosphoric acid-based such as organic phosphoric acid plasticizers. Any plasticizer is preferably liquid at room temperature. Among them, plasticizers that are ester compounds synthesized from polyhydric alcohols and fatty acids are preferred.

[0122] In addition, at least one selected from the group consisting of a silane coupling agent, a metal salt of a carboxylic acid, a metal hydroxide, and a metal carbonate can also be added to the solar radiation shielding interlayer film. The metal constituting the metal salt of the carboxylic acid, the metal hydroxide, and the metal carbonate is not particularly limited, but it is preferably at least one selected from sodium, potassium, magnesium, calcium, manganese, cesium, lithium, rubidium, and zinc. In the solar radiation shielding interlayer film, the content of at least one selected from the group consisting of the metal salt of the carboxylic acid, the metal hydroxide, and the metal carbonate is preferably 1% by mass or more and 100% by mass or less with respect to the solar radiation shielding material.

[0123] Furthermore, the solar radiation shielding interlayer film can, if necessary, in addition to the above-described solar radiation shielding material, contain at least one type of particles selected from oxide particles, composite oxide particles, and boride particles containing two or more elements selected from the group consisting of Sb, V, Nb, Ta, W, Zr, F, Zn, Al, Ti, Pb, Ga, Re, Ru, P, Ge, In, Sn, La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Y, Sm, Eu, Er, Tm, Tb, Lu, Sr, and Ca. The solar radiation shielding interlayer film can contain such particles in the range of 5% by mass or more and 95% by mass or less when the total with the solar radiation shielding material is 100% by mass.

[0124] The solar radiation shielding laminate may contain an ultraviolet absorber in at least one of the intermediate films disposed between the transparent substrates. Examples of the ultraviolet absorber include one or more selected from compounds having a malonic ester structure, compounds having an oxalic anilide structure, compounds having a benzotriazole structure, compounds having a benzophenone structure, compounds having a triazine structure, compounds having a benzoate structure, compounds having a hindered amine structure, and the like.

[0125] It goes without saying that the intermediate layer of the solar radiation shielding laminate may be composed only of the solar radiation shielding intermediate film according to the present embodiment.

[0126] The solar radiation shielding intermediate film described here is one aspect of the solar radiation shielding material dispersion. Of course, the solar radiation shielding material dispersion according to the present embodiment can be used without being sandwiched between two or more transparent substrates that transmit visible light. That is, the solar radiation shielding material dispersion according to the present embodiment can be established as a solar radiation shielding material dispersion alone.

[0127] The solar radiation shielding laminate according to the present embodiment is not limited to the form in which the solar radiation shielding material dispersion is disposed between the transparent substrates as described above, and any configuration can be adopted as long as it has a laminated structure including the solar radiation shielding material dispersion and the transparent substrate.

Example

[0128] Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples. [Example 1] The optical properties of the solar radiation shielding material containing the hexaboride were evaluated according to the following procedure.

[0129] LaB 6 and a part of La substituted with Sr, La 7 SrB 48 After obtaining the dielectric function by first-principles calculation, the absorption efficiency of the fine particles was calculated according to the Mie scattering theory formula. Incidentally, La 7 SrB 48Its valence x was selected to satisfy 0 < x < 0.3.

[0130] First-principles calculations were performed within the framework of density functional theory (DFT) using the van der Waals density functional with the plane-wave basis first-principles calculation software VASP (Vienna Ab initio Simulation Package). Also, the projector augmented wave (PAW) potential was used, with a plane-wave cutoff of 650 eV and k-points of 3×3×1.

[0131] The results are shown in Fig. 1. In Fig. 1, the plot was normalized so that the absorption efficiency in the near-infrared region becomes 1.

[0132] As shown in Fig. 1, it can be seen that by substituting La with Sr, the absorption wavelength shifts to the longer wavelength side, the absorption of red wavelengths in the visible light region is suppressed, and the transparency is improved. Also, this material has a lower transmittance than LaB 6 in the entire visible light region, and it was confirmed that it is an excellent solar radiation shielding material. [Example 2] LaB 6 A part of the B in La 8 B 47 Be was replaced with Be, and after obtaining the dielectric function of La

[0133] Be by first-principles calculation in the same manner as in Example 1, the absorption efficiency of the fine particles was calculated according to Mie's scattering theory formula. 8 B 47 Be was selected so that its valence x satisfies 0 < x < 0.3.

[0134] The results are shown in Fig. 2. In Fig. 2, the plot was normalized so that the absorption efficiency in the near-infrared region becomes 1.

[0135] As shown in Fig. 2, by replacing B with Be, it can be seen that the absorption wavelength is shifted to the longer wavelength side, the absorption of the red wavelength in the visible light region is suppressed, and the transparency is improved. Therefore, it was possible to obtain a solar radiation shielding material with excellent visible light transparency while maintaining the near-infrared absorption characteristics.

Claims

1. It contains a hexaboride containing one or more elements R selected from rare earth elements and boron, and the valence x of the hexaboride satisfies 0 < x < 0.3, The hexaboride is represented by (R1−aA1a)(B6−bA2b), where A1 is one or more selected from Sr and Ba, A2 is a substitution element or a vacancy, a satisfies 0 ≦ a < 1, and b satisfies 0 ≦ b < 6. A solar radiation shielding material.

2. The solar radiation shielding material according to claim 1, wherein the element R is La.

3. The solar radiation shielding material according to claim 1 or claim 2, wherein A2 is one or more selected from Be and Mg.

4. A solid medium, The solar radiation shielding material according to any one of claims 1 to 3 disposed in the solid medium, and A solar radiation shielding material dispersion in which the solid medium is resin or glass.

5. A transparent substrate, It has a solar radiation shielding layer disposed on at least one surface of the transparent substrate, and A solar radiation shielding transparent substrate in which the solar radiation shielding layer is the solar radiation shielding material dispersion according to claim 4.

Images