JP5632583B2 - Infrared reflective material, method for producing the same, and paint and resin composition containing the same - Google Patents

Description

  The present invention relates to a composite oxide infrared reflective material and a method for producing the same. Further, the present invention relates to a paint, a resin composition containing the infrared reflective material, and further to an infrared reflective material using the paint.

Infrared reflective material is a material that reflects infrared rays contained in sunlight, etc., and can reduce the amount of infrared rays absorbed by the ground surface, buildings, etc. covered with asphalt, concrete, etc. It is used for relaxation and improving the cooling efficiency of summer buildings.
Examples of infrared reflecting materials include chromium-containing compounds such as Cr ₂ O ₃ , Cu—Cr composite oxide, Fe—Cr composite oxide, Co—Fe—Cr composite oxide, and Cu—Cr—Mn composite oxide. Is known (see Patent Document 1). Patent Document 2 discloses an alkaline earth metal-manganese oxide represented by MexMnOy (Me is at least one metal selected from Ca, Sr, Ba, and Mg, and x is 0.01 to 99). In addition to the above-mentioned alkaline earth metal-manganese oxides, Group Ia, IIIa, IVa, Va, VIa, VIIa, VIIIa, Ib, IIb, IIIb, IVb , Vb group, VIb group, VIIIb group, pigments doped with lanthanoid elements, specifically, Ba ₂ MnO ₄ doped with 4% TiO ₂ , Sr ₂ doped with 4.5% V ₂ O ₅ MnOy, BaMnOy doped with 2% ZrO ₂ and the like are described. In addition, the development of compounds containing no chromium, such as complex oxides of rare earth elements and manganese, such as Y-Mn composite oxides, is also underway (see Patent Document 3).

JP 2000-72990 A USP6416868 JP 2002-038048 A

  Many of the infrared reflective materials contain heavy metals such as Cu, Cr, and Co, but there is a strong tendency to refrain from using materials containing such heavy metals. In particular, development of materials that do not use Cr is urgent because of concerns about the safety of Cr. However, complex oxides of alkaline earth metal elements and manganese are black pigments with relatively good infrared reflectance, but some are not sufficient compared to materials containing heavy metals, and further improved infrared reflectivity. Is required. Further, it has been pointed out that a complex oxide of rare earth element and manganese is expensive because it uses an expensive rare earth element as a raw material.

  The inventors of the present invention have developed a chromium-free infrared reflective material. When the composite oxide containing an alkaline earth metal element and a manganese element contains a specific amount of aluminum and / or gallium element, the infrared reflective material is reflected. I found that performance improved. In addition, the infrared reflecting material of the composite oxide can be manufactured by mixing an alkaline earth metal compound and a manganese element, a specific amount of an aluminum and / or gallium compound, and firing the mixture. Since the composite oxide is in powder form, it has been found that it can be used in various applications by blending it with a paint or a resin composition, thereby completing the present invention.

That is, the present invention is a composite oxide containing an alkaline earth metal element, a manganese element, and an aluminum and / or gallium element, and comprises a manganese element (Mn) and an aluminum and / or gallium element (Al). An infrared reflective material characterized in that the molar ratio is 0.0005 ≦ Al / Mn ≦ 0.50, and the solar reflectance in the wavelength range of 300 to 2100 nm calculated according to JIS R 3106 is 15% or more. is there.
Further, a manganese compound in which the molar ratio of manganese element (Mn) to aluminum and / or gallium element (Al) is 0.0005 ≦ Al / Mn ≦ 0.50, an aluminum and / or gallium compound, and alkaline earth It is a method for producing a complex oxide infrared reflecting material, characterized in that a metal oxide compound is mixed and fired.
Further, it is a paint or a resin composition characterized by containing the above-mentioned infrared reflective material, and further an infrared shielding material or the like characterized by being coated with the paint.

The infrared reflective material of the present invention is a complex oxide containing an alkaline earth metal element, a manganese element, and an oxygen element, and includes a specific amount of aluminum and / or gallium element, thereby further improving the infrared reflectivity. It becomes the black type material which has.
Such an infrared reflective material uses a heat-stable inorganic component, so it has excellent thermal stability and heat resistance, and does not contain chromium, so there is no concern about safety and environmental problems. .
Therefore, it can be used for the relaxation of the heat island phenomenon or the like by painting on the roof or outer wall of a building or painting on a road or sidewalk.
And since it can manufacture in air | atmosphere without using an expensive raw material, it can manufacture comparatively cheaply.

  The infrared reflective material of the present invention is a composite oxide containing an alkaline earth metal element, a manganese element, and an aluminum and / or gallium element. The manganese element (the number of moles of the manganese element is expressed as Mn), aluminum, and / or Or the molar ratio with the elements of gallium (the number of moles of these elements is expressed as Al) is 0.0005 ≦ Al / Mn ≦ 0.50, and the wavelength is in the range of 300-2100 nm calculated according to JIS R 3106. The solar reflectance is 15% or more.

As the alkaline earth metal element, at least one selected from calcium, strontium, and barium is preferable because it is excellent in infrared reflectivity and forms a composite oxide having a perovskite structure. The content of the alkaline earth metal element and the content of the manganese element contained in the composite oxide can be adjusted as appropriate, but an amount that forms a perovskite structure is preferable. The perovskite structure includes an ABO ₃ type structure (where A is an alkaline earth metal element excluding magnesium, B is a manganese element, and O is an oxygen element), a layered perovskite structure n (ABO ₃ ) · AO ( Here, A, B, and O are the same as described above, and can be represented as A _{n + 1} B _n O _{3n + 1,} and have a structure in which an AO layer is inserted between two ABO ₃ perovskite units. Examples include Ca ₂ MnO ₄ , Ca ₃ Mn ₂ O ₇ , Ca ₄ Mn ₃ O ₁₀ , Sr ₂ MnO ₄ , Sr ₃ Mn ₂ O ₇ , Sr ₄ Mn ₃ O ₁₀ , Ba ₄ Mn ₃ O _{10, and the} like. .) Etc.
Magnesium is an alkaline earth metal element, but generally cannot form a perovskite structure, MgMn ₂ O ₄ has a spinel structure, and Mg ₆ MnO ₈ has a rock salt structure. However, when alkaline earth metal elements other than magnesium, such as calcium, strontium, and barium, and magnesium element are used in combination as the alkaline earth metal element, a composite oxide having a perovskite structure is formed, and compared to the element without adding magnesium. However, since it has the outstanding infrared reflectivity and has the especially outstanding near-infrared reflectivity, it is more preferable. The content of magnesium can be appropriately set according to the performance such as infrared reflectivity, and the elements of magnesium (the number of moles of magnesium element is expressed as Mg) and alkaline earth metal elements other than magnesium (the moles of this element) The number ratio is more preferably 1.0 × 10 ⁻⁶ ≦ Mg / A ≦ 0.20, and further 1.0 × 10 ⁻⁶ ≦ Mg / A ≦ 0.12 preferable. The crystal structure of the complex oxide can be confirmed by X-ray diffraction.

  When the alkaline earth metal element and the manganese element contain a specific amount of aluminum and / or gallium element, the infrared reflectivity is superior to the complex oxide composed of the alkaline earth metal element and the manganese element. It becomes. The aluminum and / or gallium content is such that the molar ratio of manganese element (Mn) to aluminum and / or gallium element (Al) is 0.0005 ≦ Al / Mn ≦ 0.50. Here, Al represents the number of moles of elements of aluminum and / or gallium, and when the number of moles of elements of manganese is represented by Mn, the value of the mole ratio Al / Mn is in the range of 0.0005 to 0.50. If present, it is preferable because of having excellent infrared reflectivity, more preferably 0.001 ≦ Al / Mn ≦ 0.45, still more preferably 0.005 ≦ Al / Mn ≦ 0.35, and most preferably. 0.005 ≦ Al / Mn ≦ 0.25. When the value of Al / Mn is smaller than 0.0005, the effect of addition is not sufficient, which is not preferable. When the value of Al / Mn is larger than 0.50, generation of another phase is started, which is not preferable. The amounts of alkaline earth metal, manganese, aluminum and / or gallium elements are obtained from fluorescent X-ray analysis, and the amount of oxygen necessary to maintain the charge balance is calculated from the valences of these components.

  Aluminum and / or gallium are preferably contained as a solid solution in an alkaline earth metal-manganese composite oxide. Such a solid solution is a substitutional solid solution in which a solvent atom (specifically, an alkaline earth metal or manganese atom) at a lattice point of a composite oxide is replaced with a solute atom (specifically an aluminum or gallium atom). Or an interstitial solid solution containing solute atoms in the lattice gap of the composite oxide is formed, and the solute atoms are dissolved in the composite oxide particles and / or the particle surface. it is conceivable that. More specifically, it is presumed that a solid solution in which the above-mentioned aluminum and / or gallium solute atoms are substituted for manganese solvent atoms is formed. The fact that the element of aluminum and / or gallium is contained in the alkaline earth metal-manganese composite oxide can be confirmed from the result of X-ray diffraction by the fact that no peak of another phase other than the composite oxide appears.

Specifically, the infrared reflective material of the present invention has an infrared reflectivity of a reflectance in the wavelength range of 300 to 2100 nm in sunlight (hereinafter referred to as solar reflectance, and in accordance with JIS R 3106, the spectral reflectance is solar. It is 15% or more, preferably 20% or more, more preferably 25% or more, still more preferably 30% or more.
Further, the infrared reflective material of the present invention is preferably 20% or more, more preferably 25% or more, and still more preferably 30 when the near-infrared solar reflectance in the wavelength range of 700 to 2100 nm is similarly calculated. % Or more.

The infrared reflective material of the present invention inevitably contains impurities derived from various raw materials, but Cr is preferably not contained as much as possible, and even if contained as an impurity, it is 1% by weight or less. In particular, the content of Cr ⁶⁺ that is particularly concerned about safety is preferably 10 ppm or less.

The infrared reflective material of the present invention can be produced with various particle shapes and particle diameters by appropriately setting the production conditions. The particle shape may be, for example, a plate shape, a granular shape, a substantially spherical shape, a needle shape, an indefinite shape, and the like, and the average particle diameter (arithmetic average value of the maximum diameter of one particle) measured from an electron micrograph is 0. Those of about 0.02 to 20.0 μm are preferable. When the average particle diameter exceeds 20.0 μm, the particle size is too large, and the coloring power may be reduced. When the average particle size is less than 0.02 μm, dispersion in the paint may be difficult. For this reason, an average particle diameter becomes like this. Preferably it is 0.1-5.0 micrometers, More preferably, it is 0.2-4.5 micrometers, More preferably, it is 0.3-4.0 micrometers.
The infrared reflective material of the present invention preferably has a BET specific surface area value of about 0.05 to 80 m ² / g. When the BET specific surface area value is less than 0.05 m ² / g, the particles are coarse or the particles are sintered between the particles and the coloring power is reduced. More preferably, it is 0.2-15 m < ² > / g, More preferably, it is 0.3-5 m < ² > / g. From this BET specific surface area value, the average particle diameter regarded as spherical can be calculated by the following formula 1. The average particle size calculated from the BET specific surface area value is preferably about 0.02 to 30 μm, but may be different from the average particle size calculated from the above electron micrograph due to the influence of particle shape, particle size distribution, etc. .
Formula 1: L = 6 / (ρ · S)
Here, L is the average particle diameter (μm), ρ is the density of the sample (g / cm ³ ), and S is the BET specific surface area value (m ² / g) of the sample.

When the blackness of the infrared reflective material of the present invention is expressed by the lightness index L ^* value of CIE 1976 Lab (L ^* a ^* b ^* color system), the smaller the L ^* value is, the stronger the blackness is. The L ^* value is preferably 40 or less, more preferably 35 or less, and still more preferably 34 or less. As described above, the infrared reflective material of the present invention can be used as a black pigment because the lightness index L ^* value can be lowered.
Further, L ^* value and is determined in the same manner L ^* a ^* b ^* color system of a ^* value, b ^* value is an index representing the hue saturation and redness as a ^* value increases to the positive side The stronger the negative side, the stronger the green color, and the higher the b ^* value, the stronger the yellowish color and the negative side, the stronger the blue color. In the composite oxide, for example, the redness can be suppressed to an a ^* value of about −2 to 20 and the yellowness can be suppressed to a b ^* value of about −2 to 10.

  The infrared reflective material of the present invention can be used for paints, inks, plastics, ceramics, electronic materials, etc., but in order to increase the dispersibility in the solvent to be blended and the resin, etc. A compound or an organic compound may be coated. Examples of inorganic compounds include silicon, zirconium, aluminum, titanium oxides, and hydrated oxides. Examples of organic compounds include organic silicon compounds, organometallic compounds, polyols, alkanolamines, or derivatives thereof. Higher fatty acids or metal salts thereof, higher hydrocarbons or derivatives thereof, and the like, and at least one selected from these can be used.

  The infrared reflective material of the present invention can be produced by using a conventional method for producing a complex oxide, particularly a method for producing a perovskite complex oxide. Specifically, a so-called solid-phase synthesis method in which an alkaline earth metal compound, a manganese compound, aluminum and / or a gallium compound are mixed and fired using an electric furnace, a rotary kiln, or the like, an alkaline earth metal and manganese After synthesizing oxalate in aqueous system, aluminum and / or gallium compound is mixed and then calcined, so-called oxalate method, citrate of alkaline earth metal and manganese is synthesized in aqueous system, then aluminum And / or a mixture of gallium compounds, followed by baking, so-called citrate method, alkaline earth metal compound, manganese compound aqueous solution and aluminum and / or gallium compound and alkaline aqueous solution, and after hydrothermal treatment It is possible to use a method such as so-called hydrothermal synthesis, which is filtered, washed and dried.

  In the present invention, a solid-phase synthesis method in which an alkaline earth metal compound, a manganese compound, and an aluminum and / or gallium compound are mixed and fired is preferable because a composite oxide having an appropriate particle size can be obtained. As alkaline earth metal compounds, oxides, hydroxides, carbonates and the like can be used. As manganese compounds, aluminum and / or gallium compounds, the respective oxides, hydroxides, carbonates and the like can be used. Can be used. Next, each of the raw material compounds is weighed and mixed. The mixing amount of aluminum and / or gallium is such that the molar ratio of manganese element (Mn) to aluminum and / or gallium element (Al) is 0.0005 ≦ Al / Mn ≦ 0.50, more preferably 0.001. ≦ Al / Mn ≦ 0.45, more preferably 0.005 ≦ Al / Mn ≦ 0.35, and most preferably 0.005 ≦ Al / Mn ≦ 0.25. The mixing method may be either dry mixing in a powder state or wet mixing in a slurry state, and may be performed using a conventional mixer such as a stirring mixer. Moreover, it can also mix in the case of a grinding | pulverization, drying, granulation, and shaping | molding using various grinders, spray dryers, granulators, and molding machines.

  Next, the mixture of raw material compounds is granulated and molded as necessary, and then fired. The firing temperature may be at least a temperature at which the raw material compound undergoes a solid phase reaction, and may be, for example, a temperature in the range of 1000 to 1500 ° C. The atmosphere during firing can be any atmosphere, but firing in air is preferable in order to maintain sufficient infrared reflectivity. A flux such as sodium chloride or potassium chloride may be added during firing. The composite oxide obtained by the firing can be used in various forms such as a powder and a molded body, but when used as a powder, it may be appropriately pulverized to adjust the particle size as necessary. When used as a body, the powder may be formed into an appropriate size and shape. As the pulverizer, for example, an impact pulverizer such as a hammer mill and a pin mill, a grinding pulverizer such as a roller mill and a pulverizer, and an airflow pulverizer such as a jet mill can be used. As the molding machine, for example, a general-purpose molding machine such as an extrusion molding machine or a granulator can be used.

  In addition, the infrared reflective material of the present invention has sufficient infrared reflectivity, but when other infrared reflective compounds are mixed, the infrared reflectivity can be further increased, or the reflectivity of a specific wavelength can be increased. Can be complemented. As the compound having infrared reflectivity, those conventionally used can be used, specifically, inorganic compounds such as titanium dioxide, antimony-doped tin oxide, tungsten oxide, lanthanum boride, metallic silver powder, metallic copper. Examples thereof include metal powder such as powder, and titanium dioxide and metal powder are more preferable. The type and mixing ratio of the compound having infrared reflectivity can be appropriately selected according to the application.

  In addition, the infrared reflective material of the present invention has a black color tone, and when mixed with other pigments, the blackness can be made stronger or other colors can be obtained. As the pigment, inorganic pigments, organic pigments, lake pigments and the like can be used. Specifically, as inorganic pigments, white pigments such as titanium dioxide, zinc white, precipitated barium sulfate, iron oxide, etc. Examples thereof include red pigments, blue pigments such as ultramarine blue and prussian blue (potassium ferrocyanide), black pigments such as carbon black, and pigments such as aluminum powder. Examples of the organic pigment include organic compounds such as anthraquinone, perylene, and phthalocyanine. The type and mixing ratio of the pigment can be appropriately selected according to the color / hue.

  Next, the present invention is a paint containing the above-mentioned infrared reflective material, and the paint of the present invention includes an ink or a composition called ink. Moreover, this invention is a resin composition characterized by including the said infrared reflective material. Moreover, this invention is an infrared reflective material characterized by the coating material containing the said infrared reflective material being apply | coated on the base material.

  When the infrared reflective material of the present invention is contained in a resin such as a paint, ink, or plastic molded product such as a film, it can be made into a composition utilizing its excellent infrared reflectivity. The coating composition, ink, and resin composition may contain an arbitrary amount of infrared reflecting material with respect to the resin, preferably 0.1% by weight or more, more preferably 1% by weight or more, and still more preferably 10% by weight. % Or more. In addition, a composition forming material used in each field may be blended, and various additives may be blended.

  Specifically, in the case of paints and inks, in addition to coating film forming materials or ink film forming materials, solvents, dispersants, pigments, fillers, aggregates, thickeners, flow control agents, leveling agents, curing An agent, a crosslinking agent, a curing catalyst, and the like can be blended. Examples of coating film forming materials include organic components such as acrylic resins, alkyd resins, urethane resins, polyester resins, and amino resins, and inorganic components such as organosilicates, organotitanates, cements, and gypsum. be able to. As the ink film forming material, urethane resin, acrylic resin, polyamide resin, vinyl acetate resin, chlorinated propylene resin, and the like can be used. Various materials such as a thermosetting resin, a room temperature curable resin, and an ultraviolet curable resin can be used for these coating film forming materials and ink film forming materials without limitation, and monomer or oligomer ultraviolet curable resins are used. It is preferable to blend a photopolymerization initiator or a photosensitizer and irradiate it with ultraviolet light after application to cure, since a coating film having excellent hardness and adhesion can be obtained without applying a thermal load to the substrate.

  In addition, when the resin composition is used, in addition to the resin, the infrared ray of the present invention includes pigments, dyes, dispersants, lubricants, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, flame retardants, and bactericides. It is kneaded with a reflective material and formed into an arbitrary shape such as a film, sheet, or plate. Examples of the resin include polyolefin resins, polystyrene resins, polyester resins, acrylic resins, polycarbonate resins, fluorine resins, polyamide resins, cellulose resins, polylactic acid resins and other thermoplastic resins, phenol resins, Thermosetting resins such as urethane resins can be used. Such a resin composition can be formed into an arbitrary shape such as a film, a sheet, or a plate and used as an infrared reflecting material for industrial use, agricultural use, household use, and the like. It can also be used as a heat shield by shielding infrared rays.

  An infrared reflective material can be produced by applying the paint of the present invention on a substrate. This infrared reflecting material can be used as an infrared shielding material and further as a heat shielding material. As the substrate, various materials and materials can be used. Specifically, various building materials, civil engineering materials, etc. can be used, and the manufactured infrared reflecting material is a roof material, a wall material or a floor material of a house or a factory, or a pavement material constituting a road or a sidewalk. Can be used as The thickness of the infrared reflecting material can be arbitrarily set according to various uses. For example, when used as a roofing material, the thickness is generally 0.1 to 0.6 mm, preferably 0.1 to 0.3 mm. When used as, it is generally 0.5 to 5 mm, preferably 1 to 5 mm. In order to apply on the substrate, a method by application, spraying or a method by iron is possible, and after application, it may be dried, baked or cured as necessary.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention, this invention is not limited to those Examples.

Example 1
Calcium carbonate CaCO ₃ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 5.25 g, manganese dioxide MnO ₂ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 4.54 g and α-alumina Al ₂ O ₃ After mixing and stirring 0.01g (manufactured by High Purity Chemical Laboratories, purity 99.99%) sufficiently in an agate mortar, put a predetermined amount in an alumina crucible and firing at 1200 ° C. for 4 hours to form a perovskite type An aluminum-containing calcium manganate (sample A) having a structure was obtained.
As a result of fluorescent X-ray analysis (RIX2100, manufactured by Rigaku), the aluminum / manganese molar ratio of Sample A was 0.005. The chromium content was below the measurement detection limit.

Example 2
Calcium carbonate CaCO ₃ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 5.28 g, manganese dioxide MnO ₂ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 4.45 g and α-alumina Al ₂ O ₃ (High Purity Chemical Laboratory, purity 99.99%) 0.08g was thoroughly mixed and stirred in an agate mortar, then placed in an alumina crucible and baked at 1200 ° C for 4 hours to form a perovskite type An aluminum-containing calcium manganate (sample B) having a structure was obtained.
As a result of X-ray fluorescence analysis (RIX2100, manufactured by Rigaku), the aluminum / manganese molar ratio of Sample B was 0.03. The chromium content was below the measurement detection limit.
Further, BET specific surface area of the sample B is 0.78 m ² / g, an average particle diameter of L calculated from the density ρ = 4.6g / cm ³ of CaMnO ₃ was 1.68.

Example 3
Calcium carbonate CaCO ₃ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 5.28 g, manganese dioxide MnO ₂ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 4.45 g and gallium oxide Ga ₂ O ₃ (High purity chemical research laboratory, purity 99.99%) 0.15g was sufficiently mixed and stirred in an agate mortar, then placed in an alumina crucible and baked at 1200 ° C for 4 hours to obtain a perovskite structure Of gallium-containing calcium manganate (Sample C) was obtained.
As a result of X-ray fluorescence analysis (RIX2100, manufactured by Rigaku), the gallium / manganese molar ratio of Sample C was 0.03. The chromium content was below the measurement detection limit.

Reference example 1
Calcium carbonate CaCO ₃ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 5.05 g, manganese dioxide MnO ₂ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 2.13 g and α-alumina Al ₂ O ₃ After thoroughly mixing and stirring 0.04 g (manufactured by High Purity Chemical Laboratory, purity 99.99%) in an agate mortar, put in a predetermined amount in an alumina crucible and firing at 1200 ° C. for 4 hours to form a layered perovskite A mold-containing aluminum-containing calcium manganate (sample D) was obtained.
As a result of X-ray fluorescence analysis (RIX2100, manufactured by Rigaku), the aluminum / manganese molar ratio of Sample D was 0.03. The chromium content was below the measurement detection limit.

Comparative Example 1
5.25 g of calcium carbonate CaCO ₃ (manufactured by High Purity Chemical Laboratory, purity 99.99%) and 4.46 g of manganese dioxide MnO ₂ (manufactured by High Purity Chemical Laboratory, purity 99.99%) are sufficiently mixed in an agate mortar. -After stirring, a predetermined amount was put into an alumina crucible and calcination was performed at 1200 ° C for 4 hours to obtain a calcium manganate having a perovskite structure (sample E).
Further, BET specific surface area of the sample E is 0.69 m ² / g, an average particle diameter of L calculated from the density ρ = 4.6g / cm ³ of CaMnO ₃ was 1.90Myuemu.

Comparative Example 2
Calcium carbonate CaCO ₃ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 5.28 g, manganese dioxide MnO ₂ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 4.45 g and indium oxide In ₂ O ₃ After sufficiently mixing and stirring 0.14 g (manufactured by High-Purity Chemical Laboratory, purity 99.99%) in an agate mortar, a predetermined amount is placed in an alumina crucible and baked at 1200 ° C. for 4 hours to obtain a perovskite structure Of indium-containing calcium manganate (Sample F) was obtained.
As a result of X-ray fluorescence analysis (RIX2100, manufactured by Rigaku), the indium / manganese molar ratio of Sample F was 0.03.

Comparative Example 3
5.28 g of calcium carbonate CaCO ₃ (manufactured by High Purity Chemical Laboratory, purity 99.99%), manganese dioxide MnO ₂ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 4.45 g and boric acid H ₃ BO ₃ After thoroughly mixing and stirring 0.07 g (manufactured by High Purity Chemical Laboratory, purity 99.99%) in an agate mortar, a predetermined amount is placed in an alumina crucible and baked at 1200 ° C. for 4 hours to obtain a perovskite structure. Of boron-containing calcium manganate (Sample G) was obtained.
As a result of fluorescent X-ray analysis (RIX2100, manufactured by Rigaku), the boron / manganese molar ratio of Sample G was 0.03.

Comparative Example 4
Calcium carbonate CaCO ₃ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 7.54 g and manganese dioxide MnO ₂ (manufactured by High Purity Chemical Laboratory, purity 99.99%) 3.28 g were sufficiently mixed in an agate mortar. -After stirring, a predetermined amount was put in an alumina crucible and calcination was performed at 1200 ° C for 4 hours to obtain a layered perovskite type calcium manganate (sample H).

Samples (A to H) obtained in Examples, Reference Examples and Comparative Examples were put into a dedicated cell, and an ultraviolet-visible near-infrared spectrophotometer V-570 (manufactured by JASCO Corporation, Spectralon <manufactured by Labsphere Inc. as a standard reflector) The spectral reflectance (reflectance of light having a wavelength of 350 to 2100 nm) is measured in accordance with JIS R 3106, and then solar reflectance (reflectance in the wavelength range of 300 to 2100 nm in sunlight, solar The reflectance of near infrared rays in the wavelength range of 700 to 2100 nm in light was calculated and shown in Table 1.
The solar reflectances of the samples A, B, and C obtained in the examples are all higher than the value of the comparative sample E, and the solar reflectance of 300 to 2100 nm is expressed as a relative value where the solar reflectance of the comparative sample E is 100. Was 112 for sample A, 121 for sample B, and 127 for sample C. Moreover, since the solar reflectance of 700-2100 nm is 117 in the sample A, 130 in the sample B, and 131 in the sample C, it was found that the solar reflectance was sufficient. Samples A, B, and C obtained in the examples have higher solar reflectance than the comparative sample F containing indium and the comparative sample G containing boron, and manganese and aluminum are contained by containing aluminum and gallium. It was found that infrared reflectivity such as calcium acid can be improved.
Moreover, the solar reflectance of the sample D obtained in the reference example is higher than the values of the comparative samples E and H, and the solar reflectance of 300 to 2100 nm is expressed as a relative value where the solar reflectance of the comparative sample E is 100. It was 191 and the solar reflectance of 700 to 2100 nm was 231. Thus, it was found that it had sufficient infrared reflectivity.

Moreover, after sufficiently pulverizing the samples (B to H) obtained in Examples, Reference Examples and Comparative Examples with an agate mortar, the sample was put in a 30 mmφ aluminum ring, applied with a load of 9.8 MPa, and press-molded. The color of the powder was measured with a blackness meter NW-1 (Nippon Denshoku Industries Co., Ltd.), and the results are shown in Table 2. Samples B, C and D (aluminum or gallium-containing calcium manganate) obtained in Examples and Reference Examples have sufficient blackness, L ^* value is 40 or less, and a ^* value is Since the b ^* value shows a hue of about −1 to 1 in the range of about −1 to 1, it was found that the present invention is used as a black material.

Since Samples A to D obtained in Examples and Reference Examples are all powders, it was confirmed that they can be blended in paints and resin compositions.

The infrared reflective material of the present invention is a complex oxide containing an alkaline earth metal element, a manganese element, and an aluminum and / or gallium element, has sufficient infrared reflectivity, and has thermal stability and heat resistance. And has excellent characteristics such as safety and no concern about environmental problems, and can be used for various infrared reflection applications.
In particular, it can be used for alleviating the heat island phenomenon by painting on the roof or outer wall of a building, using a resin composition such as a film or sheet, or painting on a road or sidewalk.

Claims (5)

A composite oxide containing calcium element, manganese element and aluminum and / or gallium element,
Compositional formula 1: Aluminum and / or gallium element is dissolved in the calcium-manganese composite oxide represented by CaMnO ₃ ,
The molar ratio of the manganese element (Mn) to the aluminum and / or gallium element (Al) is 0.0005 ≦ Al / Mn ≦ 0.50,
When the solar reflectance in a wavelength range of 700 to 2100 nm calculated according to JIS R 3106 is 20% or more and the solar reflectance of the calcium-manganese composite oxide represented by the composition formula 1 is 100 An infrared reflective material characterized in that the relative solar reflectance of is at least 117. The molar ratio of the manganese element (Mn) and aluminum and / or gallium element (Al) becomes 0.0005 ≦ Al / Mn ≦ 0.50, the molar ratio of the manganese element and calcium element is 1: to be the 1 to, and mixed manganese compound and aluminum and / or a compound of gallium and a calcium compound, method for manufacturing an infrared reflective material according to claim 1, characterized in that firing. A paint comprising the infrared reflective material according to claim 1 . An infrared reflecting material, wherein the paint according to claim 3 is applied on a substrate. A resin composition comprising the infrared reflective material according to claim 1 .