Infrared absorbing fine particle powder, infrared absorbing fine particle powder dispersion, infrared absorbing fine particle dispersion, and methods for producing them

Abstract

To provide infrared absorbing fine particle powder exhibiting excellent wet heat resistance and infrared absorption characteristic, an infrared absorbing fine particle powder dispersion using the infrared absorbing fine particle powder, an infrared absorbing fine particle dispersion, and manufacturing methods therefor.SOLUTION: Provided is infrared absorbing fine particle powder obtained by arranging at least one deterioration inhibitor selected from a hydrolysis product of a metal chelate compound and a hydrate of metal oxide microscopically near an infrared absorbing fine particle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an infrared-absorbing microparticle powder, an infrared-absorbing microparticle powder dispersion, and an infrared-absorbing microparticle dispersion, each of which contains one or more deterioration inhibitors selected from the group consisting of hydrolysis products of metal chelate compounds, metal oxide hydrates, and metal oxides, and infrared-absorbing microparticles that transmit visible light and absorb infrared light, and to methods for producing the same. [Background technology]

[0002] In recent years, the demand for infrared absorbers has been increasing rapidly, and many patents related to infrared absorbers have been proposed. Looking at these proposals from a functional perspective, for example, some of them are intended to block light in the near-infrared region while allowing sufficient visible light in windows for various buildings and vehicles, thereby suppressing the rise in indoor temperature while maintaining brightness.

[0003] In Patent Document 1, the present inventors disclosed an infrared-shielding material particle dispersion in which infrared-shielding material particles are dispersed in a solvent, as well as the excellent optical properties, electrical conductivity, and manufacturing method of the infrared-shielding material particle dispersion. In particular, the infrared-shielding material particle dispersion exhibited superior infrared-shielding properties compared to conventional shielding materials. The infrared-shielding material particle dispersion is composed of tungsten oxide particles represented by the general formula WyOz (where W is tungsten, O is oxygen, and 2.2≦z / y≦2.999), or / and tungsten oxide particles represented by the general formula MxWyOz (where M is H, He, an alkali metal, an alkaline earth metal, a rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In , Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; and 0.001≦x / y≦1, 2.2≦z / y≦3.0), and the particle diameter of the infrared-shielding material particles is 1 nm or more and 800 nm or less.

[0004] Furthermore, in Patent Document 2, the present inventors have disclosed infrared-shielding microparticles having excellent water resistance and infrared-shielding properties, which are tungsten oxide microparticles represented by the general formula WyOz and / or composite tungsten oxide microparticles represented by the general formula MxWyOz, in which the average primary particle size of the microparticles is 1 nm or more and 800 nm or less, and the surfaces of the microparticles are coated with a tetrafunctional silane compound or a partial hydrolysis product thereof, and / or an organometallic compound, and a method for producing the same.

[0005] Furthermore, in Patent Document 3, the present inventors have disclosed infrared absorbing fine particles having water resistance and moist heat resistance surpassing those of Patent Document 2 and also having excellent infrared absorbing properties, and a method for producing the same. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2005 / 37932 [Patent Document 2] International Publication No. 2010 / 55570 [Patent Document 3] International Publication No. 2019 / 093524 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the water resistance and moist heat resistance of the infrared-absorbing fine particles disclosed in Patent Document 3 did not fully satisfy market demands that are increasing year by year. Due to their characteristics, infrared-absorbing materials are basically used outdoors, and they are particularly required to be resistant to long-term exposure to moist and hot atmospheres.

[0008] The present invention has been made under the above circumstances, and an object of the present invention is to provide an infrared-absorbing microparticle powder, an infrared-absorbing microparticle powder dispersion, and an infrared-absorbing microparticle dispersion, which have excellent moist heat resistance and infrared absorption properties, and methods for producing them. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the present inventors have conducted research into a configuration that makes it possible to use the tungsten oxide microparticles or / and composite tungsten oxide microparticles having excellent optical properties as infrared-absorbing microparticles, inhibit the deterioration of the infrared-absorbing microparticles, and improve their moist heat resistance and chemical stability. As a result, they have discovered that it is essential that one or more deterioration inhibitors selected from the group consisting of hydrolysis products of metal chelate compounds, metal oxide hydrates, and metal oxides are disposed in the microscopic vicinity of the infrared-absorbing microparticles.

[0010] Here, the state in which the deterioration inhibitor is disposed in the microscopic vicinity of the infrared-absorbing nanoparticles refers to a state in which the deterioration inhibitor and the infrared-absorbing nanoparticles are sufficiently mixed together, more specifically, a state in which the infrared-absorbing nanoparticles and the deterioration inhibitor are in contact with each other, or a state in which the infrared-absorbing nanoparticles and the deterioration inhibitor are not in contact with each other but are spaced apart by a distance of 50 nm or less, preferably 30 nm or less, and more preferably 10 nm or less. In this state, the deterioration inhibitor is distributed in a larger amount in the infrared absorbing fine particles and in the region of 50 nm or less, preferably 30 nm or less, and more preferably 10 nm or less, surrounding the particles, compared to other regions.

[0011] Therefore, in the present invention, a state in which the infrared absorbing particles are coated with a deterioration inhibitor, a state in which the infrared absorbing particles and the deterioration inhibitor are in contact with each other, or a state in which the infrared absorbing particles and the deterioration inhibitor are not in contact with each other but the distance between them is 50 nm or less, preferably 30 nm or less, and more preferably 10 nm or less, may be described as "the deterioration inhibitor is arranged in the microscopic vicinity of the infrared absorbing particles." In the present invention, the state in which "the deterioration inhibitor is arranged in a larger amount in the infrared absorbing microparticles and the region surrounding them, which is 50 nm or less, preferably 30 nm or less, and more preferably 10 nm or less, compared to other regions" can be rephrased as "the deterioration inhibitor is arranged in a more concentrated manner in the infrared absorbing microparticles and the region surrounding them, which is 50 nm or less, preferably 30 nm or less, and more preferably 10 nm or less, compared to other regions" or "the deterioration inhibitor is arranged in a higher density in the infrared absorbing microparticles and the region surrounding them, which is 50 nm or less, preferably 30 nm or less, and more preferably 10 nm or less, compared to other regions."

[0012] Furthermore, the present inventors discovered that an infrared-absorbing microparticle dispersion in which infrared-absorbing microparticle powder, in which a degradation inhibitor is disposed in the microscopic vicinity of the infrared-absorbing microparticles, is dispersed in a specified solid resin, has excellent moist heat resistance and infrared absorption properties, and thus arrived at the present invention.

[0013] That is, the first invention for solving the above-mentioned problems is: The present invention comprises infrared absorbing fine particles and one or more deterioration inhibitors selected from the group consisting of hydrolysis products of metal chelate compounds, hydrates of metal oxides, and metal oxides, Deterioration inhibitor infrared absorbing particles; The infrared absorbing fine particle powder is characterized in that the deterioration inhibitor is disposed in the microscopic vicinity of the infrared absorbing fine particles. [Effects of the Invention]

[0014] According to the present invention, it is possible to produce an infrared absorbing nanoparticle dispersion having excellent resistance to moist heat and infrared absorbing properties. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a schematic plan view of a crystalline structure of a composite tungsten oxide having a hexagonal crystalline structure. [Figure 2]2 shows a transmission electron microscope image and an element mapping image obtained from a thinned sample of the infrared absorbing sheet according to Example 1. [Figure 3] 10 shows a transmission electron microscope image and an element mapping image obtained from a thinned sample of the infrared absorbing sheet according to Example 2. [Figure 4] 1 shows a transmission electron microscope image and an element mapping image obtained from a thinned sample of the infrared absorbing sheet according to Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below in the following order: [1] infrared-absorbing microparticles, [2] deterioration inhibitor, [3] method for adding deterioration inhibitor, [4] infrared-absorbing microparticle powder, [5] infrared-absorbing microparticle powder dispersion, infrared-absorbing microparticle dispersion, and articles using these, and [6] state in which deterioration inhibitor is arranged in the microscopic vicinity of infrared-absorbing microparticles.

[0017] [1] Infrared absorbing particles It is generally known that materials containing free electrons exhibit a reflection-absorption response to electromagnetic waves in the wavelength range of 200 nm to 2600 nm, around the wavelength of sunlight, due to plasma oscillation. It is known that when powders of such materials are made into particles smaller than the wavelength of light, geometric scattering in the visible light range (wavelengths of 380 nm to 780 nm) is reduced, resulting in transparency in the visible light range. In the present invention, the term "transparency" is used to mean "high transmittance with little scattering of light in the visible light region."

[0018] Generally, tungsten oxide (WO3) does not have effective free electrons, so it has little absorption and reflection characteristics in the infrared region and is not effective as an infrared absorbing particle. On the other hand, WO3 with oxygen deficiency and composite tungsten oxides in which electropositive elements such as Na are added to WO3 are known to be conductive materials with free electrons. Furthermore, analysis of single crystals of these materials with free electrons suggests that the free electrons respond to light in the infrared region. The inventors have found that there is a specific range within the composition range of tungsten and oxygen that is particularly effective as infrared absorbing microparticles, and have come up with the idea of ​​tungsten oxide microparticles and composite tungsten oxide microparticles that are transparent in the visible light region and absorb in the infrared region. Here, the tungsten oxide microparticles and / or composite tungsten oxide microparticles, which are infrared-absorbing microparticles according to the present invention, will be described in the following order: (1) tungsten oxide microparticles, (2) composite tungsten oxide microparticles, and (3) optical properties of the tungsten oxide microparticles and composite tungsten oxide microparticles.

[0019] (1) Tungsten oxide particles The tungsten oxide microparticles according to the present invention are microparticles of tungsten oxide represented by the general formula WyOz (where W is tungsten, O is oxygen, and 2.2≦z / y≦2.999).

[0020] In the tungsten oxide represented by the general formula WyOz, the composition range of the tungsten and oxygen is such that the composition ratio of oxygen to tungsten is less than 3, and further, when the infrared absorbing nanoparticles are expressed as WyOz, it is preferable that 2.2≦z / y≦2.999. If the z / y value is 2.2 or more, the appearance of the undesired WO2 crystalline phase in the tungsten oxide can be avoided and the chemical stability of the material can be ensured, resulting in effective infrared absorbing particles. On the other hand, if the z / y value is 2.999 or less, the required amount of free electrons is generated, resulting in efficient infrared absorbing particles.

[0021] (2) Composite tungsten oxide particles By adding the element M described below to the above-mentioned WO3 to form a composite tungsten oxide, free electrons are generated in the WO3, and strong absorption characteristics resulting from the free electrons are exhibited, particularly in the near-infrared region, making it effective as near-infrared absorbing fine particles around 1000 nm. That is, more efficient infrared absorbing particles can be obtained by combining the control of the oxygen content with the addition of the free electron generating element M to WO3. When the general formula of the infrared absorbing particles obtained by combining the control of the oxygen content with the addition of the free electron generating element M is written as MxWyOz (where M is the element M, W is tungsten, and O is oxygen), the infrared absorbing particles preferably satisfy the relationships 0.001≦x / y≦1 and 2.0≦z / y≦3.

[0022] First, the value of x / y, which indicates the amount of element M added, will be explained. If the value of x / y is greater than 0.001, a sufficient amount of free electrons is generated in the composite tungsten oxide, and the desired infrared absorption effect can be achieved. The greater the amount of element M added, the greater the supply of free electrons and the higher the infrared absorption efficiency, but the effect saturates when the value of x / y is about 1. Furthermore, if the value of x / y is less than 1, the generation of impurity phases in the infrared-absorbing nanoparticles can be avoided, which is preferable.

[0023] Furthermore, the element M is preferably one or more elements selected from H, He, alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, and Yb.

[0024] From the viewpoint of stability in MxWyOz to which the element M is added, the element M is more preferably one or more elements selected from alkali metals, alkaline earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, and Re. From the viewpoint of improving the optical properties and weather resistance of the infrared absorbing nanoparticles, the element M is even more preferably an alkaline earth metal element, a transition metal element, a Group 4B element, or a Group 5B element.

[0025] Next, the z / y value, which indicates the control of oxygen content, will be described. Regarding the z / y value, in the composite tungsten oxide represented by MxWyOz, the same mechanism as that of the tungsten oxide represented by WyOz described above also works, and even when z / y=3.0 or 2.0≦z / y≦2.2, there is also the supply of free electrons due to the amount of added element M described above. Therefore, 2.0≦z / y≦3.0 is preferred, 2.2≦z / y≦3.0 is more preferred, and 2.45≦z / y≦3.0 is even more preferred.

[0026] Furthermore, when the composite tungsten oxide microparticles have a hexagonal crystal structure, the microparticles have improved transmittance in the visible light region and improved absorption in the infrared region. This will be explained with reference to Figure 1, which is a schematic plan view of this hexagonal crystal structure. In FIG. 1, six octahedra formed by WO6 units, indicated by the reference numeral 11, are assembled to form a hexagonal void, and an element M, indicated by the reference numeral 12, is arranged in the void to form one unit, and many of these units are assembled to form a hexagonal crystal structure. In order to obtain the effects of improving light transmission in the visible light region and improving light absorption in the infrared region, the composite tungsten oxide microparticles need only contain the unit structure described with reference to FIG. 1, and the composite tungsten oxide microparticles may be crystalline or amorphous.

[0027] When cations of element M are added and present in these hexagonal voids, light transmission in the visible light region is improved and light absorption in the infrared region is improved. Generally, the hexagonal crystal is easily formed when an element M with a large ionic radius is added. Specifically, hexagonal crystals are easily formed when Cs, K, Rb, Tl, In, Ba, Li, Ca, Sr, Fe, or Sn is added. Of course, elements other than these may also be used as long as the above-mentioned element M is present in the hexagonal voids formed by the WO6 units, and the present invention is not limited to the above-mentioned elements.

[0028] When the composite tungsten oxide microparticles having a hexagonal crystal structure have a uniform crystal structure, the amount of the additive element M added is preferably such that the value of x / y is 0.001≦x / y≦1, more preferably 0.2≦x / y≦0.5, and even more preferably 0.33. When the value of x / y is 0.33, it is believed that the above-mentioned element M is arranged in all of the hexagonal voids.

[0029] In addition, composite tungsten oxides other than hexagonal crystals, such as tetragonal and cubic crystals, are also effective as infrared-absorbing microparticles. The absorption position in the infrared region tends to change depending on the crystal structure, with the absorption position tending to shift to the longer wavelength side in the order of cubic crystals < tetragonal crystals < hexagonal crystals. Additionally, the order of lowest absorption in the visible light region is hexagonal, tetragonal, and cubic crystals. Therefore, for applications requiring greater transmission of light in the visible light region and greater absorption of light in the infrared region, it is preferable to use hexagonal composite tungsten oxide. However, the trends in the optical properties described here are merely rough trends, and will vary depending on the type and amount of added element and the amount of oxygen, and the present invention is not limited thereto.

[0030] (3) Optical properties of tungsten oxide particles and composite tungsten oxide particles The infrared-absorbing particles containing tungsten oxide particles or composite tungsten oxide particles according to the present invention largely absorb light in the near-infrared region, particularly in the vicinity of 1000 nm in wavelength, and therefore many of them have a transmitted color tone ranging from blue to green.

[0031] The particle size of the tungsten oxide particles or composite tungsten oxide particles dispersed in the infrared absorbing particles can be selected depending on the intended use. First, when used in applications where transparency must be maintained, it is preferable for the particle diameter to be 800 nm or less. This is because particles smaller than 800 nm do not completely block light due to scattering, and can maintain visibility in the visible light range while efficiently maintaining transparency. In particular, when transparency in the visible light range is important, it is preferable to further consider scattering by the particles.

[0032] When the reduction of scattering by particles is important, the dispersed particle diameter should be 200 nm or less, preferably 100 nm or less. The reason for this is that if the dispersed particle diameter of the particles is small, scattering of light in the visible light region with wavelengths of 400 nm to 780 nm due to geometric scattering or Mie scattering is reduced, which prevents the infrared absorbing film from becoming like frosted glass and losing clear transparency. In other words, when the dispersed particle diameter is 200 nm or less, the geometric scattering or Mie scattering is reduced, and the Rayleigh scattering region is reached. In the Rayleigh scattering region, scattered light is reduced in proportion to the sixth power of the particle diameter, so scattering is reduced and transparency is improved as the dispersed particle diameter decreases. Furthermore, a dispersed particle size of 100 nm or less is preferable because scattered light is significantly reduced. From the viewpoint of avoiding light scattering, a small dispersed particle size is preferable, and a dispersed particle size of 1 nm or more facilitates industrial production.

[0033] By setting the dispersed particle diameter to 800 nm or less, the haze value of the infrared absorbing nanoparticle dispersion in which the infrared absorbing nanoparticles according to the present invention are dispersed in a solvent can be set to 30% or less at a visible light transmittance of 85% or less. If the haze value is greater than 30%, the result will resemble cloudy glass, and clear transparency will not be obtained. The dispersed particle size of the infrared absorbing fine particles can be measured using an ELS-8000 manufactured by Otsuka Electronics Co., Ltd., which is based on the principle of dynamic light scattering.

[0034] Furthermore, among tungsten oxide particles and composite tungsten oxide particles, the so-called "Magnéli phase" having a composition ratio expressed as 2.45≦z / y≦2.999 is chemically stable and has good absorption characteristics in the infrared region, making it preferable as infrared absorbing particles. Furthermore, from the viewpoint of exhibiting excellent infrared absorption properties, the crystallite diameter of the infrared-absorbing fine particles is preferably 1 nm or more and 200 nm or less, more preferably 1 nm or more and 100 nm or less, and even more preferably 10 nm or more and 70 nm or less. The crystallite diameter is measured by measuring the X-ray diffraction pattern by powder X-ray diffraction (θ-2θ method) and analyzing by the Rietveld method. The X-ray diffraction pattern can be measured using, for example, a powder X-ray diffractometer such as "X'Pert-PRO / MPD" manufactured by PANalytical, Spectris Co., Ltd.

[0035] [2] Deterioration inhibitor The deterioration inhibitor disposed in the microscopic vicinity of the infrared-absorbing nanoparticles according to the present invention is one or more metal compounds selected from the group consisting of hydrolysis products of metal chelate compounds, metal oxide hydrates, and metal oxides, where the hydrolysis products of metal chelate compounds conceptually include polymers of hydrolysis products of metal chelate compounds. From the viewpoint that the metal chelate compound is preferably a metal alkoxide, a metal acetylacetonate, or a metal carboxylate, it is preferable that the metal chelate compound has one or more groups selected from an ether bond, an ester bond, an alkoxy group, and an acetyl group. Here, the deterioration inhibitor according to the present invention will be described in the following order: (1) metal chelate compound, (2) hydrolysis product and polymer of metal chelate compound, (3) metal oxide hydrate, (4) metal oxide, and (5) the amount of deterioration inhibitor added.

[0036] (1) Metal chelate compounds The metal chelate compound used as a raw material for the deterioration inhibitor according to the present invention is preferably one or more selected from Al-, Zr-, Ti-, Si- and Zn-based chelate compounds containing an alkoxy group.

[0037] Examples of aluminum-based chelate compounds include aluminum alcoholates such as aluminum ethylate, aluminum isopropylate, aluminum sec-butylate, and mono-sec-butoxyaluminum diisopropylate, or polymers thereof, ethyl acetoacetate aluminum diisopropylate, aluminum tris(ethyl acetoacetate), octyl acetoacetate aluminum diisopropylate, stearyl acetoaluminum diisopropylate, aluminum monoacetylacetonate bis(ethyl acetoacetate), and aluminum tris(acetylacetonate). These compounds are alkoxy-containing aluminum chelate compounds obtained by dissolving aluminum alcoholate in an aprotic solvent, petroleum solvent, hydrocarbon solvent, ester solvent, ketone solvent, ether solvent, amide solvent, or the like, adding β-diketone, β-ketoester, monohydric or polyhydric alcohol, fatty acid, or the like to the solution, heating under reflux, and subjecting the solution to a ligand substitution reaction.

[0038] Examples of zirconia-based chelate compounds include zirconium alcoholates such as zirconium ethylate and zirconium butyrate, or polymers thereof, zirconium tributoxystearate, zirconium tetraacetylacetonate, zirconium tributoxyacetylacetonate, zirconium dibutoxybis(acetylacetonate), zirconium tributoxyethylacetoacetate, and zirconium butoxyacetylacetonate bis(ethylacetoacetate).

[0039] Examples of titanium-based chelate compounds include titanium alcoholates such as methyl titanate, ethyl titanate, isopropyl titanate, butyl titanate, and 2-ethylhexyl titanate, and polymers thereof, titanium acetylacetonate, titanium tetraacetylacetonate, titanium octylene glycolate, titanium ethylacetoacetate, titanium lactate, and titanium triethanolamine.

[0040] As the silicon-based chelate compound, a tetrafunctional silane compound represented by the general formula: Si(OR)4 (where R is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms), or a hydrolysis product thereof, can be used. Specific examples of tetrafunctional silane compounds include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. Furthermore, silane monomers in which some or all of the alkoxy groups of these alkoxysilane monomers have been hydrolyzed to form silanol (Si-OH) groups, as well as polymers self-condensed through hydrolysis, can also be used. Furthermore, examples of hydrolysis products of tetrafunctional silane compounds (there is no appropriate terminology that indicates the entire intermediate product of a tetrafunctional silane compound) include silane monomers in which some or all of the alkoxy groups have been hydrolyzed to form silanol (Si-OH) groups. Note that not all of the alkoxysilyl groups (Si-OR) in the alkoxysilane monomers are hydrolyzed to form silanol (Si-OH) groups during the hydrolysis reaction.

[0041] Preferred examples of zinc-based chelate compounds include organic zinc carboxylates such as zinc octylate, zinc laurate, and zinc stearate, acetylacetone zinc chelate, benzoylacetone zinc chelate, dibenzoylmethane zinc chelate, and ethyl acetoacetate zinc chelate.

[0042] (2) Hydrolysis products and polymers of metal chelate compounds In the present invention, hydrolysis products in which all of the alkoxy groups, ether bonds, and ester bonds in the above-mentioned metal chelate compounds have been hydrolyzed to form hydroxyl groups or carboxyl groups, partial hydrolysis products in which some of the compounds have been hydrolyzed, and / or polymers self-condensed through the hydrolysis reaction are also placed in the microscopic vicinity of the infrared-absorbing nanoparticles of the present invention as deterioration inhibitors. That is, the hydrolysis product in the present invention is a concept that includes a partial hydrolysis product.

[0043] (3) Hydrate of metal oxide The hydrate of metal oxide used as the deterioration inhibitor according to the present invention preferably contains one or more metal elements selected from Al, Zr, Ti, Si, and Zn. Specifically, for example, it is more preferable that they are Al2O3·nH2O (0 < n ≤ 3), ZrO2·nH2O (0 < n ≤ 2), TiO2·nH2O (0 < n ≤ 2), SiO2·nH2O (0 < n ≤ 2), ZnO·nH2O (0 < n ≤ 1). Incidentally, these hydrates of metal oxides are also hydrolysis products of the metal chelate compounds shown in (2).

[0044] (4) Metal oxide The metal oxide used as the deterioration inhibitor according to the present invention preferably contains one or more metal elements selected from Al, Zr, Ti, Si, and Zn. Specifically, for example, it is more preferable that they are aluminum oxide, zirconium oxide, titanium oxide, silicon oxide, and zinc oxide.

[0045] (5) Addition amount of deterioration inhibitor The addition amount of the above-mentioned deterioration inhibitor is preferably 0.1 part by mass or more and 1000 parts by mass or less in terms of metal element with respect to 100 parts by mass of the infrared absorption fine particles. More preferably, it is in the range of 1 part by mass or more and 500 parts by mass or less. Even more preferably, it is in the range of 10 parts by mass or more and 150 parts by mass or less.

[0046] This is because when there is 0.1 part by mass or more of the deterioration inhibitor with respect to 100 parts by mass of the infrared absorption fine particles, the hydrolysis products of those compounds and the polymers of the hydrolysis products are arranged in the microscopic vicinity of the infrared absorption fine particles, and the effect of improving the heat and humidity resistance is exerted, and the effect of improving the heat and humidity resistance can be obtained. Also, when the deterioration inhibitor is 1000 parts by mass or less with respect to 100 parts by mass of the infrared absorption fine particles, the improvement in heat and humidity resistance due to being arranged in the microscopic vicinity of the infrared absorption fine particles does not saturate, and an improvement in the addition effect can be expected. Furthermore, by using 1000 parts by mass or less of the deterioration inhibitor per 100 parts by mass of the infrared-absorbing nanoparticles, it is possible to avoid the deterioration inhibitor being added in excess to the infrared-absorbing nanoparticles, which would otherwise cause the nanoparticles to easily granulate with each other during solvent removal. By avoiding this unwanted granulation of the nanoparticles, it is possible to ensure good transparency. In addition, it is possible to avoid increases in raw material costs due to an excess of the deterioration inhibitor and increases in production costs due to an increase in processing time. Therefore, from an industrial viewpoint, it is preferable that the amount of deterioration inhibitor added is 1,000 parts by mass or less per 100 parts by mass of the infrared-absorbing nanoparticles.

[0047] [3] How to add deterioration inhibitors The method of adding the deterioration inhibitor according to the present invention will be described below. First, a metal chelate compound or a cyclic metal oligomer compound, which is a raw material for the degradation inhibitor, is added to a solvent containing water as the main component, and the degradation inhibitor raw material is hydrolyzed to produce a degradation inhibitor-containing solution containing one or more compounds selected from the group consisting of a hydrolysis product of the metal chelate compound or the cyclic metal oligomer compound, a polymer of the hydrolysis product, and a metal oxide hydrate. Alternatively, a metal oxide obtained by heat-treating a metal oxide hydrate may be used as the degradation inhibitor. Alternatively, a metal oxide hydrate or metal oxide synthesized by a known method may be used as the degradation inhibitor. On the other hand, infrared absorbing fine particles are dispersed in a water-soluble solvent to prepare an infrared absorbing fine particle dispersion for mixing (sometimes referred to as a "dispersion for mixing" in the present invention). The deterioration inhibitor-containing liquid is then added to the prepared dispersion for mixing, and the mixture is stirred and mixed, thereby adding the deterioration inhibitor according to the present invention. The method of adding the deterioration inhibitor raw material according to the present invention will be described in the order of (1) deterioration inhibitor-containing liquid, (2) infrared absorbing nanoparticle dispersion liquid for mixing, and (3) mixing and stirring.

[0048] (1) Liquid containing deterioration inhibitor A degradation inhibitor-containing liquid is obtained by adding a metal chelate compound or a metal cyclic oligomer compound, which is a raw material for the degradation inhibitor, to a liquid solvent containing water as the main component and allowing a hydrolysis reaction to proceed. Here, the inventors have discovered that when preparing this deterioration inhibitor-containing liquid, it is preferable to add the deterioration inhibitor raw material to a solvent containing water as its main component while stirring and mixing it, thereby immediately completing the hydrolysis reaction of the added deterioration inhibitor raw material.

[0049] This is thought to be due to the reaction order of the degradation inhibitor raw material added to a solvent containing water as the main component, that is, in a solvent containing water as the main component, the hydrolysis reaction of the degradation inhibitor raw material always precedes, followed by the polymerization reaction of the resulting hydrolysis product. This is because it is believed that this reaction sequence can reduce the amount of residual carbon (C) derived from the degradation inhibitor raw material that will be present in the degradation inhibitor-containing liquid compared to when a solvent that does not contain water as a main component is used.

[0050] Furthermore, it is believed that by reducing the amount of residual carbon (C) derived from the degradation inhibitor raw material present in the degradation inhibitor-containing liquid, it was possible to position a large amount of degradation inhibitor in the microscopic vicinity of the infrared absorbing microparticles.

[0051] When adding the degradation inhibitor raw material dropwise to a liquid solvent containing water as the main component, it is also preferable to dilute the degradation inhibitor raw material itself with an appropriate solvent in advance to prepare a diluted raw material, and then add the diluted raw material dropwise in order to adjust the amount of degradation inhibitor raw material added per unit time. The solvent used for dilution is preferably one that does not react with the degradation inhibitor raw material or the solvent and is highly compatible with water. Specifically, alcohol-based, ketone-based, glycol-based, and other solvents can be preferably used. The dilution ratio of the deterioration inhibitor raw material is not particularly limited, but from the viewpoint of ensuring productivity, the dilution ratio is preferably 100 times or less.

[0052] The optimum water content in the deterioration inhibitor-containing solution depends on the hydrolysis reaction rate of the deterioration inhibitor raw material. Generally, the higher the water content in the deterioration inhibitor-containing solution, the better, and it is preferably 50 to 100 parts by weight per 100 parts by weight of the total solvent. It is also preferably 100 parts by weight or more per 100 parts by weight of the deterioration inhibitor raw material.

[0053] Furthermore, it is preferable that the deterioration inhibitor be dispersed in the deterioration inhibitor-containing liquid in the form of fine particles, because when the deterioration inhibitor is dispersed in the form of fine particles, it can be easily arranged in the microscopic vicinity of the infrared-absorbing fine particles.

[0054] In addition, in the deterioration inhibitor-containing solution, the added deterioration inhibitor raw material may be decomposed into metal ions immediately after the start of addition, but even in such a case, there is no particular problem because the decomposition into the metal ions ends when the deterioration inhibitor becomes saturated in the solution.

[0055] Furthermore, by heating the liquid medium when adding the degradation inhibitor raw material to a liquid solvent containing water as the main component, the hydrolysis reaction rate of the degradation inhibitor raw material can be adjusted. Furthermore, although the amount of hydrolysis of the resulting degradation inhibitor varies depending on the water content and heating state of the degradation inhibitor-containing liquid, in any case, the hydrolysis reaction yields one or more degradation inhibitors selected from a partial hydrolysis product, a hydrolysis product, a polymer of the hydrolysis product, and a hydrate of a metal oxide.

[0056] Furthermore, by heat treating a hydrate of a metal oxide at a predetermined temperature or higher, an anhydrous metal oxide can be obtained, and the anhydrous metal oxide can be used as a deterioration inhibitor.

[0057] (2) Infrared absorbing nanoparticle dispersion for mixing In the dispersion for mixing according to the present invention, it is preferable to previously finely grind the infrared-absorbing nanoparticles, tungsten oxide and / or composite tungsten oxide, and disperse them in a water-soluble solvent to obtain a monodispersed state. During the grinding and dispersion process, it is essential to maintain the dispersion state and prevent the nanoparticles from aggregating. This is to avoid the situation where the nanoparticles aggregate, and the aggregates remain in the infrared-absorbing nanoparticle dispersion described below, thereby reducing the transparency of the infrared-absorbing nanoparticle dispersion described below.

[0058] As a result, by subjecting the dispersion liquid for mixing according to the present invention to a pulverization and dispersion treatment, when the deterioration inhibitor-containing liquid according to the present invention is added, the deterioration inhibitor can be uniformly arranged in the microscopic vicinity of each infrared-absorbing microparticle.

[0059] Specific methods for pulverizing and dispersing the infrared absorbing microparticles include, for example, pulverizing and dispersing methods using devices such as a bead mill, a ball mill, a sand mill, a paint shaker, an ultrasonic homogenizer, etc. Among these, pulverizing and dispersing with a media agitating mill such as a bead mill, a ball mill, a sand mill, or a paint shaker using media such as beads, balls, or Ottawa sand is preferred because it takes a short time for the infrared absorbing microparticles to reach the desired dispersed particle size.

[0060] As the water-soluble solvent, water, alcohol-based, ketone-based, glycol-based, and other solvents can be preferably used.

[0061] (3) Mixing and stirring While stirring the above-mentioned dispersion for mixing, the deterioration inhibitor-containing liquid is added and mixed and stirred to obtain an infrared-absorbing nanoparticle dispersion containing the deterioration inhibitor. At this time, a stirring device capable of mixing and stirring so that the deterioration inhibitor is uniformly present in the infrared-absorbing nanoparticle dispersion containing the deterioration inhibitor is used. For example, a stirrer with blades that has shear force is preferable, but is not particularly limited.

[0062] [4] Infrared absorbing fine particle powder The infrared-absorbing microparticle dispersion liquid containing the deterioration inhibitor, obtained by the mixing and stirring and in which the deterioration inhibitor is uniformly present, is subjected to a drying process to remove the liquid solvent, thereby obtaining the infrared-absorbing microparticle powder of the present invention, in which the deterioration inhibitor is arranged in microscopic proximity to the infrared-absorbing microparticles.

[0063] The mechanism by which the deterioration inhibitor located in the microscopic vicinity of the infrared-absorbing fine particles improves the water resistance and moist heat resistance of the infrared-absorbing fine particles has not yet been elucidated. The present inventors speculate that the deterioration inhibitor changes the electrostatic potential around the infrared-absorbing fine particles, creating a field in which the deterioration reaction of the infrared-absorbing fine particles does not occur.

[0064] During the drying treatment, care must be taken to ensure that the drying temperature does not exceed the temperature at which the infrared absorbing microparticle powder strongly aggregates to form strong aggregates. Therefore, it is preferable to obtain the infrared absorbing microparticle powder of the present invention by drying the infrared absorbing microparticle dispersion containing the deterioration inhibitor, for example, by vacuum fluidized drying or spray drying at around room temperature.

[0065] This is because the infrared-absorbing nanoparticle dispersion or the infrared-absorbing substrate to be finally used is often required to have transparency for its intended use, and if an infrared-absorbing nanoparticle dispersion or an infrared-absorbing substrate is produced using a strongly aggregated infrared-absorbing nanoparticle powder as the infrared-absorbing material, the resulting product will have a high degree of haze.

[0066] Therefore, if the infrared-absorbing microparticle powder is heat-treated at a temperature exceeding the temperature at which it forms strong agglomerates, the strongly agglomerated infrared-absorbing microparticle powder must be dry- and / or wet-disintegrated and redispersed in order to ensure the transparency of the infrared-absorbing microparticle dispersion and the infrared-absorbing base material. However, when the strongly agglomerated infrared-absorbing microparticle powder is disintegrated and redispersed, it becomes difficult to arrange the deterioration inhibitor in the microscopic vicinity of the infrared-absorbing microparticles, and the desired water resistance and moist heat resistance may not be obtained.

[0067] In contrast, in the vacuum fluidized bed drying process, the infrared-absorbing microparticle powder is simultaneously dried and disintegrated under a reduced pressure. This allows for a fast drying rate and prevents agglomeration. Furthermore, because the drying is performed under a reduced pressure, the solvent can be removed at a relatively low temperature, minimizing the amount of residual solvent. In addition, in the spray drying process, secondary agglomeration of the infrared-absorbing microparticle powder due to the surface force of the solvent is unlikely to occur, and an infrared-absorbing microparticle powder with relatively little secondary agglomeration can be obtained without disintegration.

[0068] [5] Infrared absorbing microparticle powder dispersion, infrared absorbing microparticle dispersion, and articles using these The infrared-absorbing microparticle powder dispersion and infrared-absorbing microparticle dispersion obtained using the infrared-absorbing microparticle powder according to the present invention, as well as articles using these, will be described below in the following order: (1) infrared-absorbing microparticle powder dispersion, (2) infrared-absorbing microparticle dispersion, (3) infrared-absorbing substrate which is an example of the infrared-absorbing microparticle dispersion, and (4) articles using the infrared-absorbing microparticle dispersion or the infrared-absorbing substrate.

[0069] (1) Infrared absorbing fine particle powder dispersion The infrared absorbing microparticle powder dispersion according to the present invention is a dispersion of the infrared absorbing microparticle powder according to the present invention in a liquid solvent, which may be one or more liquid solvents selected from organic solvents, oils and fats, liquid plasticizers, compounds that are polymerized by curing, and water. The infrared absorbing microparticle powder dispersion liquid according to the present invention will be described in the following order: (i) organic solvent used, (ii) oils and fats used, (iii) liquid plasticizer used, (iv) compound used that is polymerized by curing, (v) dispersant used, (vi) production method, and (vii) method of using the infrared absorbing microparticle powder dispersion liquid.

[0070] (i) Organic solvents used Examples of organic solvents used in the infrared absorbing fine particle powder dispersion according to the present invention include alcohol-based, ketone-based, hydrocarbon-based, glycol-based, and water-based solvents. Specifically, alcohol solvents such as methanol, ethanol, 1-propanol, isopropanol, butanol, pentanol, benzyl alcohol, and diacetone alcohol; Ketone solvents such as acetone, methyl ethyl ketone, dimethyl ketone, methyl propyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone; Ester solvents such as 3-methyl-methoxy-propionate, n-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, and propylene glycol ethyl ether acetate; Amides such as formamide, N-methylformamide, dimethylformamide, dimethylacetamide, and N-methyl-2-pyrrolidone; Aromatic hydrocarbons such as toluene and xylene; Examples include ethylene chloride and chlorobenzene. Among these organic solvents, particularly preferred are dimethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, toluene, propylene glycol monomethyl ether acetate, and n-butyl acetate.

[0071] (ii) Fats and oils used Examples of the oils and fats used in the infrared absorbing fine particle powder dispersion according to the present invention include vegetable oils and fats, plant-derived compounds, petroleum-based solvents, and the like. Examples of vegetable oils include drying oils such as linseed oil, sunflower oil, tung oil, and perilla oil; semi-drying oils such as sesame oil, cottonseed oil, rapeseed oil, soybean oil, rice bran oil, and poppy seed oil; and non-drying oils such as olive oil, coconut oil, palm oil, and dehydrated castor oil. Examples of compounds derived from vegetable oils include fatty acid monoesters and ethers obtained by directly esterifying fatty acids of vegetable oils with monoalcohols. Commercially available petroleum-based solvents can also be used as oils and fats. Commercially available petroleum solvents include Isopar (registered trademark) E, Exxor (registered trademark) Hexane, Heptane, E, D30, D40, D60, D80, D95, D110, and D130 (all manufactured by ExxonMobil Corporation).

[0072] (iii) Liquid plasticizers used Examples of the liquid plasticizer used in the infrared absorbing fine particle powder dispersion according to the present invention include a plasticizer which is a compound of a monohydric alcohol and an organic acid ester, an ester-based plasticizer such as a polyhydric alcohol organic acid ester compound, a phosphoric acid-based plasticizer such as an organic phosphoric acid-based plasticizer, etc. It is preferable that any of these plasticizers is liquid at room temperature. Among these, plasticizers that are ester compounds synthesized from polyhydric alcohols and fatty acids can be preferably used. The ester compounds synthesized from the polyhydric alcohols and fatty acids are not particularly limited, but examples thereof include glycol ester compounds obtained by reacting glycols such as triethylene glycol, tetraethylene glycol, and tripropylene glycol with monobasic organic acids such as butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptyl acid, n-octylic acid, 2-ethylhexyl acid, pelargonic acid (n-nonylic acid), and decyl acid. Further examples include ester compounds of tetraethylene glycol or tripropylene glycol with the above-mentioned monobasic organic solvents. Among these, fatty acid esters of triethylene glycol such as triethylene glycol dihexanate, triethylene glycol di-2-ethyl butyrate, triethylene glycol di-octanate, and triethylene glycol di-2-ethylhexanoate can be used. Furthermore, fatty acid esters of triethylene glycol can also be preferably mentioned.

[0073] (iv) Compounds that are polymerized by curing The compound to be polymerized by curing and used in the infrared absorbing fine particle powder dispersion according to the present invention includes a monomer or oligomer that forms a polymer by polymerization or the like. Specific examples include methyl methacrylate monomer, acrylate monomer, styrene resin monomer, and the like.

[0074] The liquid solvents described above can be used in combination of two or more kinds. Furthermore, if necessary, an acid or alkali may be added to these liquid solvents to adjust the pH.

[0075] (v) Dispersants used In order to further improve the dispersion stability of the infrared absorbing fine particle powder and to prevent the dispersed particle size from increasing due to re-aggregation, it is also preferable to add various dispersants, surfactants, coupling agents, etc. to the infrared absorbing fine particle powder dispersion liquid according to the present invention. The dispersant, coupling agent, and surfactant can be selected depending on the application, but those having an amine-containing group, a hydroxyl group, a carboxyl group, a sulfo group, or an epoxy group as a functional group are preferred. These functional groups adsorb to the surface of the infrared-absorbing fine particles, preventing aggregation and allowing them to be dispersed uniformly. Polymeric dispersants having any of these functional groups in the molecule are even more preferred.

[0076] Additionally, acrylic-styrene copolymer dispersants having functional groups are also preferred dispersants. Among these, acrylic-styrene copolymer dispersants having a carboxyl group as the functional group and acrylic dispersants having an amine-containing group as the functional group are more preferred examples. Dispersants having an amine-containing group as the functional group preferably have a molecular weight Mw of 2000 to 200,000 and an amine value of 5 to 100 mgKOH / g. Furthermore, dispersants having a carboxyl group preferably have a molecular weight Mw of 2000 to 200,000 and an acid value of 1 to 50 mgKOH / g.

[0077] Preferred examples of commercially available dispersants include SOLSPERSE (registered trademark) manufactured by Lubrizol Japan Corporation (hereinafter the same) 3000, 5000, 9000, 11200, 12000, 13000, 13240, 13650, 13940, 16000, 17000, 18000, 20000, 21000, 24000SC, 24000GR, 26000, 27000, and 280 00, 31845, 32000, 32500, 32550, 32600, 33000, 33500, 34750, 35100, 35200, 36600, 37500, 38500, 39000, 41000, 41090, 53095, 55000, 56000, 71000, 76500, J180, J200, M387, etc.; SOLPLUS (registered trademark) (hereinafter the same) D5 10, D520, D530, D540, DP310, K500, L300, L400, R700, etc.; Disperbyk (registered trademark) manufactured by BYK Japan (hereinafter the same) - 101, 102, 103, 106, 107, 108, 109, 110, 111, 112, 116, 130, 140, 142, 145, 154, 161, 162, 163, 164, 165, 16 6, 167, 168, 170, 171, 174, 180, 181, 182, 183, 184, 185, 190, 191, 192, 2000, 2001, 2009, 2020, 2025, 2050, 2070, 2095, 2096, 2150, 2151, 2152, 2155, 2163, 2164, Anti-Terra (registered trademark) (hereinafter the same)-U, 203, 204, etc.;BYK (registered trademark) (hereinafter the same) - P104, P104S, P105, P9050, P9051, P9060, P9065, P9080, 051, 052, 053, 054, 055, 057, 063, 065, 066N, 067A, 077, 088, 141, 220S, 300, 302, 306, 307, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 340, 345, 346, 347, 348, 350, 354, 355, 358N, 361N, 370, 375, 377, 378, 380N, 381, 392, 410, 425, 430, 1752, 4510, 6919, 9076, 9077, W909, W935, W940, W961, W966, W969, W972, W980, W985, W995, W996, W9010, Dynwet80 0, Cyclean3700, UV3500, UV3510, UV3570, etc.; EFKA (registered trademark) manufactured by EFKA Additives (hereinafter the same) 2020, 2025, 3030, 3031, 3236, 4008, 4009, 4010, 4015, 4020, 4046, 4047, 4050, 4055, 4060, 4080, 4300, 4310, 4320, 4330, 4340, 4400, 440 1, 4402, 4403, 4500, 5066, 5220, 6220, 6225, 6230, 6700, 6780, 6782, 7462, 8503, etc.; JONCRYL (registered trademark) manufactured by BASF Japan Ltd. (hereinafter the same) 67, 678, 586, 611, 680, 682, 690, 819, -JDX5050, etc.; TERPLUS (registered trademark) manufactured by Otsuka Chemical Co., Ltd. (hereinafter the same) MD1000, D1180, D 1130, etc.; Ajinomoto Fine-Techno Co., Inc., Ajisper (registered trademark) (hereinafter the same) PB-711, PB-821, PB-822, etc.; Kusumoto Chemicals Co., Ltd., Disparlon (registered trademark) (hereinafter the same) 1751N, 1831, 1850, 1860, 1934, DA-400N, DA-703-50, DA-325, DA-375, DA-550, DA-705, DA-725, DA-1401, DA-7301, DN-900, NS-5210, NVI-8514L, etc.Examples of such products include Alphon (registered trademark) UH-2170, UC-3000, UC-3910, UC-3920, UF-5022, UG-4010, UG-4035, UG-4040, and UG-4070, and Reseda (registered trademark) GS-1015, GP-301, and GP-301S, manufactured by Toagosei Co., Ltd.; and Dianall (registered trademark) BR-50, BR-52, BR-60, BR-73, BR-80, BR-83, BR-85, BR-87, BR-88, BR-90, BR-96, BR102, BR-113, and BR-116, manufactured by Mitsubishi Chemical Corporation.

[0078] (vi) Manufacturing method To produce the infrared-absorbing microparticle powder dispersion according to the present invention, the infrared-absorbing microparticle powder is added to a liquid solvent and dispersed. Examples of methods for redispersing include the specific pulverization and dispersion treatment methods described in "(2) Infrared-absorbing microparticle dispersion for mixing (3) Method for adding a deterioration inhibitor." However, if the infrared-absorbing microparticle powder is pulverized by excessive pulverization and dispersion treatment, the deterioration inhibitor may not be retained in the microscopic vicinity of the infrared-absorbing microparticles. Therefore, it is preferable to limit the pulverization and dispersion treatment to a minimum. However, if excessive pulverization and dispersion treatment causes the deterioration inhibitor to be unable to remain in the microscopic vicinity of the infrared-absorbing particles, the solvent can be removed again after the pulverization and dispersion treatment to produce the infrared-absorbing particle dispersion powder described below. By removing the solvent again, the deterioration inhibitor that had once left the microscopic vicinity of the infrared-absorbing particles reassembles and is again positioned in the microscopic vicinity of the infrared-absorbing particles.

[0079] (vii) Method of using the infrared absorbing fine particle powder dispersion Methods for using the infrared-absorbing microparticle powder dispersion according to the present invention will be described in the following order: (a) infrared-absorbing base material, (b) powdered infrared-absorbing microparticle dispersion, (c) curable ink composition, and (d) thermoplastic resin-containing ink composition.

[0080] (a) Infrared absorbing substrate The infrared absorbing microparticle powder dispersion according to the present invention can be used as an infrared absorbing substrate by applying it to the surface of a suitable substrate to form a dispersion film thereon. In other words, the dispersion film is a type of infrared absorbing microparticle dispersion, which will be described later, and is also a type of dried and solidified product of the infrared absorbing microparticle powder dispersion, which will also be described later.

[0081] (b) Powdered infrared absorbing microparticle dispersion The infrared-absorbing microparticle powder dispersion according to the present invention can be dried and pulverized to obtain the powdered infrared-absorbing microparticle dispersion according to the present invention (sometimes referred to as "dispersed powder" in the present invention). That is, the dispersed powder is a type of infrared-absorbing microparticle dispersion described later, and is also a type of dried and solidified infrared-absorbing microparticle powder dispersion described later.

[0082] The dispersed powder is a powdery dispersion in which infrared-absorbing fine particles are dispersed in a solid medium (such as a dispersant), and is a concept distinct from the infrared-absorbing fine particles described above. Because the dispersed powder contains a dispersant, the infrared-absorbing fine particles can be easily redispersed in a suitable medium by mixing it with the medium.

[0083] The configuration of mixing the dispersed powder with an appropriate medium and easily redispersing the infrared-absorbing microparticles into the medium is thought to relocate the deterioration inhibitors to the microscopic vicinity of the infrared-absorbing microparticles even if they have been temporarily removed from the microscopic vicinity of the infrared-absorbing microparticles during the pulverization and dispersion treatment of the infrared-absorbing microparticle powder dispersion. Therefore, it can be said that the infrared-absorbing microparticle dispersed powder is a particularly preferred application example among infrared-absorbing microparticle dispersions.

[0084] The dispersed powder can be used as a raw material for adding the infrared absorbing nanoparticles in a dispersed state to an infrared absorbing product. That is, the dispersed powder in which the infrared absorbing nanoparticles according to the present invention are dispersed in a solid medium may be dispersed again in a liquid medium and used as a dispersion liquid for an infrared absorbing product, or the dispersed powder may be kneaded into a resin as described below.

[0085] (c) Curable ink composition The infrared absorbing fine particle powder dispersion liquid obtained by mixing and dispersing the infrared absorbing fine particles according to the present invention in a liquid medium is used in various applications that utilize light-to-heat conversion. For example, a curable ink composition can be obtained by adding infrared absorbing particles to an uncured thermosetting resin, or by dispersing the infrared absorbing particles according to the present invention in an appropriate solvent and then adding an uncured thermosetting resin. The curable ink composition exhibits excellent adhesion to a substrate when applied to the substrate and cured by irradiation with infrared or other electromagnetic waves. The infrared-absorbing fine particles act as an auxiliary agent that increases the amount of heat generated by infrared irradiation. In addition to its use as a conventional ink, the curable ink composition is also ideal for stereolithography, in which a predetermined amount of ink is applied, cured by irradiation with infrared or other electromagnetic waves, and stacked to form a three-dimensional object.

[0086] (d) Thermoplastic resin-containing ink composition A thermoplastic resin-containing ink composition can be obtained by adding the infrared absorbing microparticle powder of the present invention to a heat-molten thermoplastic resin, or by dispersing the infrared absorbing microparticle powder of the present invention in a suitable solvent and then adding a thermoplastic resin that is highly soluble in the solvent. The thermoplastic resin-containing ink composition is applied to a predetermined substrate, and adheres to the substrate after solvent removal and resin heat fusion by irradiation with infrared or other electromagnetic waves. The infrared-absorbing fine particle powder acts as an auxiliary agent to increase the amount of heat generated by infrared irradiation. In addition to its use as a conventional ink, the thermoplastic resin-containing ink composition can also be applied in a predetermined amount and then repeatedly irradiated with infrared or other electromagnetic waves to remove the solvent and heat fusion the resin, making it an ideal thermoplastic resin-containing ink composition for stereolithography, a method for creating three-dimensional objects.

[0087] (2) Infrared absorbing particle dispersion The infrared absorbing nanoparticle dispersion according to the present invention is a dispersion in which the infrared absorbing nanoparticles according to the present invention and a deterioration inhibitor are dispersed in a solid medium in a state where they coexist in microscopic proximity. The solid medium may be a solid resin, glass, or the like. The infrared absorbing nanoparticle dispersions according to the present invention that are in the form of a film, a board, or a powder will be described in the order of (i) solid resin, (ii) production method, and (iii) moist heat resistance.

[0088] (i) Solid resin The solid resin that forms the matrix of the above-mentioned film, board, and powder is not particularly limited and can be selected according to the application. Low-cost, highly transparent, and versatile resins that can be used include PET resin, acrylic resin, polyamide resin, vinyl chloride resin, polycarbonate resin, olefin resin, epoxy resin, and polyimide resin. Fluorine resins can also be used in consideration of weather resistance. Two or more types selected from these solid resins can also be used.

[0089] (ii) Manufacturing method When the infrared-absorbing microparticle powder according to the present invention is kneaded into a resin and molded into a film or board, the infrared-absorbing microparticle powder can be kneaded directly into the resin. Alternatively, the infrared-absorbing microparticle powder dispersion liquid described above can be mixed with the resin, or the powdered infrared-absorbing microparticle dispersion (dispersed powder) described above can be added to a liquid medium and then mixed with the resin. When a resin is used as the solid medium, a film or board having a thickness of, for example, 0.1 μm to 50 mm can be formed.

[0090] Generally, when the infrared absorbing fine particle powder according to the present invention is kneaded into a solid resin, it is mixed and kneaded while heating at a temperature near the melting point of the solid resin (around 200 to 300° C.). In this case, the infrared-absorbing fine particle powder can be further mixed with a solid resin and pelletized, and the pellets can be formed into a film or board by various methods. For example, they can be formed by extrusion molding, inflation molding, solution casting, casting, etc. The thickness of the film or board can be appropriately set depending on the intended use, and the amount of filler relative to the resin (i.e., the amount of infrared-absorbing fine particles blended according to the present invention) can be varied depending on the thickness of the substrate and the required optical and mechanical properties, but is generally preferably 50 mass % or less relative to the resin. When the amount of filler relative to the resin is 50% by mass or less, the particles in the solid resin can be prevented from agglomerating with each other, thereby maintaining good transparency.Furthermore, the amount of the infrared-absorbing particles according to the present invention used can be controlled, which is advantageous in terms of cost.

[0091] The infrared-absorbing microparticle dispersion in which the infrared-absorbing microparticle powder according to the present invention is dispersed in a solid medium can also be used in a powdered state by further pulverizing it. When this configuration is adopted, the infrared-absorbing microparticle powder according to the present invention is already sufficiently dispersed in a solid medium such as the above-mentioned solid resin in the powdered infrared-absorbing microparticle dispersion. Therefore, the powdered infrared-absorbing microparticle dispersion can be used as a so-called masterbatch and dissolved in an appropriate liquid medium or kneaded with resin pellets or the like, thereby easily producing a liquid or solid infrared-absorbing microparticle dispersion.

[0092] When various infrared absorbing microparticle dispersions (dispersed powders, masterbatches, etc.) in which the infrared absorbing microparticle powder according to the present invention is dispersed in a solid medium are kneaded with resin pellets, etc., it is considered that the deterioration inhibitor is unlikely to leave the microscopic vicinity of the infrared absorbing microparticles, because the shear force generated during the kneading is not so great. Furthermore, in order to ensure the dispersion of the infrared-absorbing microparticle powder, the above-mentioned dispersant is often used in combination. However, due to differences in the molecular structures of the dispersant and the resin to be kneaded, the two are rarely completely compatible with each other, and in many cases, the kneaded dispersant exists in the resin in the form of islands. As a result, the resin and the dispersant are microscopically separated. Here, the infrared-absorbing microparticles and the degradation inhibitor are modified by the functional groups of the dispersant, so they are retained within the separated islands of the dispersant. Therefore, when various infrared-absorbing microparticle dispersions are kneaded with resin pellets, etc., it is thought that the degradation inhibitor is located in the microscopic vicinity of the infrared-absorbing microparticles.

[0093] (iii) Moisture and heat resistance When the infrared-absorbing nanoparticle dispersion according to the present invention is exposed to a moist heat atmosphere at a temperature of 85°C and a relative humidity of 90% for 1000 hours, the change in the average light transmittance in the wavelength range of 800 nm to 1000 nm before and after the exposure is 1.8% or less, and the dispersion has excellent moist heat resistance.

[0094] (3) Infrared absorbing substrate, which is an example of an infrared absorbing nanoparticle dispersion The infrared absorbing substrate, which is one example of the infrared absorbing fine particle dispersion according to the present invention, is a substrate having a dispersion film containing the infrared absorbing fine particle powder according to the present invention formed on the surface thereof. By forming a dispersion film containing the infrared-absorbing microparticle powder of the present invention on the surface of a specified substrate, the infrared-absorbing substrate of the present invention has excellent moist heat resistance and chemical stability, and can be suitably used as an infrared-absorbing material. The infrared absorbing substrate according to the present invention will be described in the order of (i) the production method and (ii) the moist heat resistance.

[0095] (i) Manufacturing method For example, an infrared-absorbing substrate in which the infrared-absorbing microparticle powder according to the present invention is mixed with an organic solvent such as alcohol or a liquid medium such as water, a resin binder, and optionally a dispersant, is coated on the surface of a suitable substrate, and the liquid medium is then removed or cured, thereby obtaining an infrared-absorbing substrate in which the infrared-absorbing microparticle dispersion is directly laminated on the surface of the substrate.

[0096] The resin binder component can be selected depending on the application, and examples thereof include ultraviolet-curable resins, thermosetting resins, room-temperature-curable resins, thermoplastic resins, etc. On the other hand, an infrared-absorbing fine particle powder dispersion liquid containing no resin binder component may be laminated on the surface of a substrate, or after the lamination, a liquid medium containing a binder component may be applied onto the layer of the infrared-absorbing fine particle dispersion.

[0097] Specifically, examples of such an infrared-absorbing substrate include a substrate surface coated with a liquid infrared-absorbing microparticle dispersion in which infrared-absorbing microparticle powder is dispersed in one or more liquid media selected from organic solvents, organic solvents in which resins are dissolved, organic solvents in which resins are dispersed, and water, and the resulting coating film is solidified by an appropriate method. Other examples include an infrared-absorbing substrate obtained by coating a substrate surface with a liquid infrared-absorbing microparticle dispersion containing a resin binder component and solidifying the resulting coating film by an appropriate method. Still other examples include an infrared-absorbing substrate obtained by mixing an infrared-absorbing microparticle dispersion in which infrared-absorbing microparticle powder is dispersed in a powdery solid medium with a predetermined medium, coating the substrate surface with a liquid infrared-absorbing microparticle dispersion, and solidifying the resulting coating film by an appropriate method. Of course, examples of such an infrared-absorbing substrate include a substrate surface coated with an infrared-absorbing microparticle powder dispersion in which two or more of the various liquid infrared-absorbing microparticle powder dispersions are mixed, and solidifying the resulting coating film by an appropriate method.

[0098] The material of the substrate is not particularly limited as long as it is transparent, but glass, a resin board, a resin sheet, or a resin film is preferably used. The resins used for resin boards, resin sheets, and resin films are not particularly limited as long as they do not cause problems in the surface condition or durability of the required boards, sheets, or films. Examples include boards, sheets, and films made of transparent polymers such as polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, polycarbonate polymers, acrylic polymers such as polymethyl methacrylate, styrene polymers such as polystyrene and acrylonitrile-styrene copolymers, polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers. These include vinyl chloride polymers, amide polymers such as aromatic polyamides, imide polymers, sulfone polymers, polyethersulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, and epoxy polymers, as well as various binary and ternary copolymers, graft copolymers, and blends thereof. In particular, biaxially oriented polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate are preferred in terms of mechanical properties, optical properties, heat resistance, and cost efficiency. The biaxially oriented polyester film may be a copolymer polyester film.

[0099] (ii) Moisture and heat resistance When the infrared-absorbing base material, which has a visible light transmittance of 80%, is exposed to a moist and hot atmosphere of 85°C and 90% humidity for 1000 hours, the change in the average light transmittance in the wavelength range of 800 nm to 1000 nm before and after the exposure is 1.8% or less, and the base material has excellent moist and heat resistance.

[0100] (4) Articles using infrared absorbing nanoparticle dispersions or infrared absorbing substrates As described above, the infrared absorbing nanoparticle dispersion according to the present invention and the infrared absorbing article such as a film or board, which is an infrared absorbing substrate, are excellent in moist heat resistance and chemical stability. Therefore, these infrared-absorbing articles can be suitably used, for example, in window materials in various buildings and vehicles that allow sufficient visible light in while blocking light in the infrared region, thereby suppressing temperature increases inside the room while maintaining brightness, and in filters used in PDPs (plasma display panels) that block infrared rays emitted forward from the PDP.

[0101] Furthermore, since the infrared-absorbing microparticle powder according to the present invention has absorption in the infrared region, when an infrared laser is irradiated onto a printed surface containing the infrared-absorbing microparticle powder, the infrared light having a specific wavelength is absorbed. Therefore, an anti-counterfeit printed matter obtained by printing an anti-counterfeit ink containing this infrared-absorbing microparticle powder onto one or both sides of a printing substrate can be irradiated with infrared light having a specific wavelength and the reflection or transmission thereof measured, allowing the authenticity of the printed matter to be determined from the difference in the amount of reflection or transmission. The anti-counterfeit printed matter is an example of the infrared-absorbing microparticle dispersion according to the present invention.

[0102] Furthermore, a photothermal conversion layer can be formed by mixing the infrared-absorbing microparticle powder dispersion of the present invention with a binder component to produce an ink, applying the ink to a substrate, drying the applied ink, and then curing the dried ink. The photothermal conversion layer can generate heat only at desired locations with high positional precision when irradiated with an electromagnetic laser such as infrared light, and is applicable to a wide range of fields, including electronics, medicine, agriculture, and machinery. For example, it can be suitably used as a donor sheet used in forming organic electroluminescence elements by laser transfer, thermal paper for thermal printers, or ink ribbons for thermal transfer printers. The photothermal conversion layer is an example of the infrared-absorbing microparticle dispersion of the present invention.

[0103] Furthermore, infrared-absorbing fibers can be obtained by dispersing the infrared-absorbing microparticle powder according to the present invention in a suitable medium and incorporating the dispersion into the surface and / or interior of fibers. This configuration allows the infrared-absorbing fiber to efficiently absorb near-infrared rays from sunlight and other sources, resulting in an infrared-absorbing fiber with excellent heat retention properties. At the same time, the infrared-absorbing fiber transmits light in the visible light range, resulting in an infrared-absorbing fiber with excellent design properties. As a result, the infrared-absorbing fiber can be used in a variety of applications, including textile products that require heat retention, such as cold weather clothing, sportswear, stockings, and curtains, as well as other industrial textile products. This infrared-absorbing fiber is an example of the infrared-absorbing microparticle dispersion according to the present invention.

[0104] Furthermore, the film- or board-shaped infrared-absorbing nanoparticle dispersion according to the present invention can be applied to materials used for the roofs or exterior walls of agricultural and horticultural greenhouses. The film- or board-shaped infrared-absorbing nanoparticle dispersion according to the present invention can be used as a heat-insulating material for agricultural and horticultural facilities, which transmits visible light to ensure the light necessary for photosynthesis of plants in the agricultural and horticultural greenhouses, while efficiently absorbing other light, such as near-infrared light, contained in sunlight. This heat-insulating material for agricultural and horticultural facilities is an example of the infrared-absorbing nanoparticle dispersion according to the present invention.

[0105] [6] The deterioration inhibitor is placed in the microscopic vicinity of the infrared absorbing particles. In the state where the degradation inhibitor is disposed in the microscopic vicinity of the infrared-absorbing nanoparticles, a larger amount of degradation inhibitor is disposed in the infrared-absorbing nanoparticles and the region surrounding them within 50 nm, preferably 30 nm, and more preferably 10 nm, compared to other regions. This can be confirmed by taking a TEM image of the infrared-absorbing nanoparticles, an elemental mapping image of the elements contained in the infrared-absorbing nanoparticles (e.g., tungsten) in the same field of view as the TEM image, and an elemental mapping image of the elements contained in the degradation inhibitor (e.g., aluminum) in the same field of view as the TEM image, and analyzing these images. This can be confirmed by preparing a degradation inhibitor-containing liquid obtained by hydrolyzing a metal chelate compound or a cyclic metal oligomer compound, which is the degradation inhibitor raw material, and uniformly mixing it with the infrared-absorbing nanoparticles, thereby allowing the degradation inhibitor to be observed in a concentrated state. Furthermore, when a metal oxide hydrate or metal oxide that does not undergo hydrolysis is used as the degradation inhibitor, the degradation inhibitor can be observed in a concentrated state by uniformly mixing it with the infrared-absorbing nanoparticles together with a specified solvent. Examples of a method for uniformly mixing include a method of vigorously mixing for a long period of time, such as 24 hours or more, using a stirrer with blades, or a method of mixing using a media stirring mill.

[0106] 2, (a) is a TEM image of the infrared absorbing particles in Example 1 described below, (b) is an elemental mapping image of the element (tungsten) contained in the infrared absorbing particles in the same field of view as the TEM image, and (c) is an elemental mapping image of the element (aluminum) contained in the degradation inhibitor. Also, FIG. 3 is a similar image in Example 2, and FIG. 4 is a similar image in Comparative Example 1. The elemental mapping images were measured by energy dispersive X-ray analysis (EDX or EDS). In the infrared absorbing nanoparticles of Examples 1 and 2, the degradation inhibitor is disposed in the microscopic vicinity thereof, and therefore a large amount of the degradation inhibitor, as shown in the aluminum elemental mapping image, is disposed in the vicinity (within a range of 10 nm or less) of the infrared absorbing nanoparticles, as shown in the TEM image and the tungsten elemental mapping image. On the other hand, it can be seen that the amount of the degradation inhibitor present is small in the region where the infrared absorbing nanoparticles are not present. In contrast, in the infrared absorbing nanoparticles of Comparative Example 1, the degradation inhibitor is not located in large amounts in the microscopic vicinity thereof, and therefore it can be seen that the degradation inhibitor, as shown in the aluminum elemental mapping image, is not located in the vicinity of the infrared absorbing nanoparticles, as shown in the TEM image and the tungsten elemental mapping image. It can also be seen that the degradation inhibitor is present and dispersed almost uniformly throughout the entire field of view. [Example]

[0107] The present invention will be specifically described below with reference to examples, although the present invention is not limited to the following examples. The particle size of the dispersed particles in the dispersions in the examples and comparative examples is shown as an average value measured using a particle size analyzer based on dynamic light scattering (ELS-8000 manufactured by Otsuka Electronics Co., Ltd.) The crystallite size was measured by powder X-ray diffraction (θ-2θ method) using a powder X-ray diffractometer (X'Pert-PRO / MPD manufactured by PANalytical, Spectris Inc.), and calculated using the Rietveld method.

[0108] The optical properties of the infrared-absorbing sheet were measured using a spectrophotometer (U-4100 manufactured by Hitachi, Ltd.) in the wavelength range of 200 nm to 2600 nm at 5 nm intervals, and the visible light transmittance was calculated in accordance with JIS R 3106. The average value of the light transmittance in the wavelength range of 800 nm to 1000 nm was calculated as the solar transmittance. The haze value of the infrared-absorbing sheet was measured using a haze meter (HM-150 manufactured by Murakami Color Co., Ltd.) and calculated in accordance with JIS K 7105.

[0109] The moist heat resistance of an infrared-absorbing sheet was evaluated by exposing the sheet, which had a visible light transmittance of about 80%, to a moist heat atmosphere at a temperature of 85°C and a relative humidity of 90% for 1000 hours. Sheets with a change in solar radiation transmittance of 1.8% or less before and after exposure were judged to have good moist heat resistance, and sheets with a change of more than 1.8% were judged to have insufficient moist heat resistance. The optical property values ​​(visible light transmittance, haze value) of the infrared absorbing sheet referred to here include the optical property values ​​of the resin sheet that is the substrate.

[0110] [Example 1] Hexagonal cesium tungsten bronze (Cs / W (molar ratio) = 0.33) 0.33 WO z 2.0≦z≦3.0) powder CWO (registered trademark) (YM-01 manufactured by Sumitomo Metal Mining Co., Ltd.) 25% by mass and 75% by mass of pure water were mixed to obtain a mixture, which was then loaded into a paint shaker containing 0.3 mm diameter ZrO2 beads and subjected to a pulverization and dispersion treatment for 10 hours to obtain the Cs according to Example 1. 0.33 WO z A dispersion of fine particles was obtained.

[0111] Cs in the obtained dispersion 0.33 WO z The dispersed particle diameter of the fine particles was measured to be 100 nm. The particle diameter measurement settings were a particle refractive index of 1.81 and a non-spherical particle shape. The background was measured using pure water, and the solvent refractive index was 1.33. After removing the solvent from the resulting dispersion, the crystallite diameter was measured to be 32 nm. The obtained Cs 0.33 WO z The dispersion of fine particles was mixed with pure water, and Cs 0.33 WO z A mixing dispersion A according to Example 1 was obtained, which contained 2% by mass of fine particles.

[0112] On the other hand, as a deterioration inhibitor, 13 mass% of aluminum ethyl acetoacetate diisopropylate, an aluminum-based chelate compound, 4 mass% of isopropyl alcohol (IPA), and 83 mass% of pure water were mixed, and the hydrolysis reaction of the chelate compound was carried out to obtain deterioration inhibitor-containing liquid a.

[0113] 890 g of the resulting dispersion A for mixing was placed in a beaker, and while vigorously stirring with a bladed stirrer for 48 hours, 69 g of deterioration inhibitor-containing solution a was added thereto. After the addition, the solvent was evaporated from the aged solution by vacuum fluidized drying, and the infrared absorbing fine particle powder of Example 1 was obtained.

[0114] In this case, since the molecular weight of aluminum ethyl acetoacetate diisopropylate is 274.3 and the atomic weight of aluminum is 26.98, the metal amount (aluminum amount) in aluminum ethyl acetoacetate diisopropylate is 9.8 mass%. Therefore, the metal amount in 69 g of deterioration inhibitor-containing liquid a containing 9 g of deterioration inhibitor is 0.89 g.

[0115] On the other hand, in 890 g of dispersion A for forming a coating film, Cs 0.33 WO z Since the content of the fine particles is 2% by mass, the amount of the infrared absorbing fine particles is 17.8 g. From the above, the amount of deterioration inhibitor per 100 parts by mass of infrared absorbing fine particles is 5 parts by mass in terms of metal element.

[0116] 8% by mass of the infrared absorbing fine particle powder according to Example 1, 24% by mass of a polyacrylate dispersant, and 68% by mass of toluene were mixed. The resulting mixture was loaded into a paint shaker containing 0.3 mmφ ZrO2 beads and subjected to a pulverization and dispersion treatment for 1 hour to obtain an infrared absorbing fine particle powder dispersion according to Example 1. Next, the solvent was evaporated from this infrared absorbing fine particle powder dispersion by vacuum fluidization drying, to obtain an infrared absorbing fine particle dispersion according to Example 1.

[0117] The infrared-absorbing microparticle dispersion powder according to Example 1 and a polycarbonate resin were dry-blended so that the visible light transmittance of the resulting infrared-absorbing sheet would be around 80% (in this example, the content of the infrared-absorbing microparticles was blended to be 0.06% by mass). The resulting blend was kneaded at 290°C using a twin-screw extruder, extruded through a T-die, and formed into a 0.75 mm-thick sheet material by a calendar roll method, thereby obtaining the infrared-absorbing sheet according to Example 1. The infrared-absorbing sheet is an example of the infrared-absorbing microparticle dispersion according to the present invention.

[0118] The optical properties of the obtained infrared-absorbing sheet of Example 1 were measured, and the visible light transmittance was 79.7%, the solar radiation transmittance (average value of transmittance at wavelengths of 800 nm to 1000 nm) was 32.4%, and the haze was 1.1%.

[0119] The obtained infrared-absorbing sheet according to Example 1 was exposed to a humid and hot atmosphere at a temperature of 85°C and a relative humidity of 90% for 1000 hours, and then its optical properties were measured. The results were a visible light transmittance of 80.5%, a solar radiation transmittance (average value of transmittance at wavelengths of 800nm ​​to 1000nm) of 33.8%, and a haze of 1.1%. The change in visible light transmittance due to exposure to the humid and hot atmosphere was small, at 0.8%, and a change in the average value of transmittance at wavelengths of 800nm ​​to 1000nm of 1.4%, both of which were small, and it was found that the haze did not change. The production conditions are shown in Table 1, and the evaluation results are shown in Table 2.

[0120] A thinned sample of the infrared-absorbing sheet according to Example 1 was prepared using a microtome and observed using a transmission electron microscope (HF-2200, manufactured by Hitachi, Ltd.). The TEM image of the infrared-absorbing particles shown in FIG. 2(a) was obtained, as was the elemental mapping image of tungsten atoms in the same field of view as in (a) shown in (b), and the elemental mapping image of aluminum atoms in the same field of view as in (a) shown in (c). As is clear from FIGS. 2(a), (b), and (c), a large amount of deterioration inhibitor containing aluminum atoms is located in the microscopic vicinity (within a range of 10 nm or less) of the infrared-absorbing particles containing tungsten atoms. On the other hand, it can be seen that the amount of deterioration inhibitor present is small in areas where no infrared-absorbing particles are present. The elemental mapping was carried out using an energy dispersive X-ray analyzer (NORAN System SIX manufactured by Thermo Fisher Scientific Co., Ltd.) attached to a transmission electron microscope.

[0121] [Example 2] The same operations as in Example 1 were carried out except that the amount of deterioration inhibitor-containing liquid a added was changed from 69 g to 345 g, thereby obtaining an infrared absorbing microparticle powder, an infrared absorbing microparticle dispersion liquid, an infrared absorbing microparticle dispersion powder, and an infrared absorbing sheet according to Example 2, and the same evaluations were carried out as in Example 1. The conditions are shown in Table 1, and the evaluation results are shown in Table 2.

[0122] As in Example 1, a thinned sample of the infrared-absorbing sheet according to Example 2 was prepared using a microtome and observed using a transmission electron microscope. The resulting TEM image of the infrared-absorbing particles shown in Figure 3(a), the elemental mapping image of tungsten atoms in the same field of view as in (a) shown in (b), and the elemental mapping image of aluminum atoms in the same field of view as in (a) shown in (c) were obtained. As is clear from Figures 3(a), (b), and (c), a large amount of deterioration inhibitor containing aluminum atoms is located in the microscopic vicinity (within a range of 10 nm or less) of the infrared-absorbing particles containing tungsten atoms. On the other hand, it can be seen that the amount of deterioration inhibitor present is small in areas where no infrared-absorbing particles are present.

[0123] [Example 3] The solvent was evaporated from the deterioration inhibitor-containing liquid a by vacuum fluidized drying, and the resulting solution was then heat-treated in a nitrogen atmosphere at 400° C. for 1 hour to obtain a deterioration inhibitor-containing powder according to Example 3.

[0124] The components of the resulting degradation inhibitor-containing powder were analyzed using an ICP optical emission spectrometer (Shimadzu Corporation, Model: ICPE9000), revealing that it contained 53% aluminum by mass. Furthermore, the oxygen content of the degradation inhibitor-containing powder was measured using an inert gas fusion oxygen analyzer (LECO Corporation, Model: TC436), revealing that it contained 47% oxygen by mass. Furthermore, analysis using a thermal analyzer consisting of a thermobalance (Bruker AXS) connected to a mass spectrometer (Q-MS, Bruker AXS) revealed that the water content was below the detection limit (less than 0.1% by mass). The thermal analyzer analysis was performed by heating from room temperature to 1300°C at a rate of 10°C / min with an Ar carrier gas flow rate of 130 cc / min. Gas components with mass-to-charge ratios of m / z = 17 and 18 were considered to be all water, and the amount of water generated was evaluated. From the above, it was confirmed that the deterioration inhibitor-containing powder according to Example 3 was anhydrous aluminum oxide.

[0125] Next, we investigated the hexagonal cesium tungsten bronze (Cs) with a Cs / W (molar ratio) of 0.33. 0.33 WO z , 2.0≦z≦3.0) powder CWO (registered trademark) (YM-01 manufactured by Sumitomo Metal Mining Co., Ltd.) 7.31 mass %, 0.69 mass % of the deterioration inhibitor-containing powder according to Example 3 (i.e., anhydrous aluminum oxide), 24 mass % of a polyacrylate-based dispersant, and 68 mass % of toluene were mixed. The resulting mixture was placed in a paint shaker containing 0.3 mm diameter ZrO2 beads and subjected to a pulverization and dispersion treatment for 10 hours to obtain an infrared absorbing fine particle powder dispersion according to Example 3. After removing the solvent from the resulting dispersion, Cs 0.33 WO z The crystallite diameter of the powder containing the deterioration inhibitor was measured and found to be 32 nm. At this time, the metal content (aluminum content) in the deterioration inhibitor-containing powder was 53 mass %. Therefore, the metal content in the deterioration inhibitor-containing powder was 53 mass %. 0.33 WO zThis is 0.37% by mass compared to 7.31% by mass. From the above, the amount of deterioration inhibitor per 100 parts by mass of infrared absorbing fine particles is 5 parts by mass in terms of metal element. Next, the solvent was evaporated from this infrared ray absorbing fine particle powder dispersion liquid by vacuum fluidized drying, and an infrared ray absorbing fine particle dispersion powder according to Example 3 was obtained.

[0126] An infrared absorbing sheet was obtained by the same operation as in Example 1, except that the infrared absorbing microparticle dispersion powder of Example 3 was used instead of the infrared absorbing microparticle dispersion powder of Example 1, and evaluations were carried out in the same manner as in Example 1. The evaluation results are shown in Table 2. Furthermore, in the infrared-absorbing sheet according to Example 3, a large amount of deterioration inhibitor containing aluminum atoms is disposed in the microscopic vicinity (within a range of 10 nm or less) of the infrared-absorbing particles containing tungsten atoms, while it was confirmed that the amount of deterioration inhibitor present is small in the region where the infrared-absorbing particles are not present.

[0127] [Comparative Example 1] Hexagonal cesium tungsten bronze (Cs / W (molar ratio) = 0.33) 0.33 WO z , 2.0≦z≦3.0) powdered CWO (registered trademark) (YM-01 manufactured by Sumitomo Metal Mining Co., Ltd.) 7% by mass, 24% by mass of a polyacrylate-based dispersant, and 69% by mass of toluene were mixed, and the resulting mixture was loaded into a paint shaker containing 0.3 mmφ ZrO2 beads and subjected to a pulverization and dispersion treatment for 4 hours, thereby obtaining an infrared absorbing nanoparticle dispersion according to Comparative Example 1.

[0128] The dispersed particle diameter of the infrared-absorbing nanoparticles in the obtained infrared-absorbing nanoparticle dispersion was measured and found to be 100 nm. The particle diameter measurement settings were a particle refractive index of 1.81 and a non-spherical particle shape. The background was measured using toluene, and the solvent refractive index was set to 1.50. After removing the solvent from the obtained dispersion, the crystallite diameter was measured and found to be 32 nm. The solvent was evaporated from the infrared absorbing nanoparticle dispersion liquid according to Comparative Example 1 by vacuum fluidized drying, to obtain an infrared absorbing nanoparticle dispersion powder according to Comparative Example 1.

[0129] Next, the solvent was evaporated from the deterioration inhibitor-containing liquid a according to Example 1 by vacuum fluidized bed drying to obtain a deterioration inhibitor-containing powder. 7% by mass of the obtained deterioration inhibitor-containing powder, 24% by mass of a polyacrylate dispersant, and 69% by mass of toluene were mixed, and the resulting mixture was loaded into a paint shaker containing 0.3 mm diameter ZrO2 beads and subjected to a pulverization and dispersion treatment for 4 hours in the same manner as for the above-mentioned infrared absorbing microparticle dispersion, to obtain a deterioration inhibitor microparticle dispersion. The solvent was then evaporated from the degradation inhibitor fine particle dispersion by vacuum fluidized drying to obtain a degradation inhibitor fine particle dispersion powder.

[0130] The infrared absorbing fine particle dispersion powder according to Comparative Example 1 and the degradation inhibitor fine particle dispersion powder were mixed in a weight ratio of 10:1, and then dry-blended with polycarbonate resin to determine the content of the infrared absorbing fine particles. The obtained blend was kneaded at 290°C using a twin-screw extruder, extruded through a T-die, and formed into a sheet material with a thickness of 0.75 mm using a calendar roll method, thereby obtaining an infrared absorbing sheet according to Comparative Example 1.

[0131] The optical properties of the obtained infrared absorbing sheet according to Comparative Example 1 were measured, and it was found that the visible light transmittance was 79.2%, the average transmittance at wavelengths of 800 nm to 1000 nm was 32.6%, and the haze was 1.0%.

[0132] The obtained infrared-absorbing sheet according to Comparative Example 1 was exposed to a humid and hot atmosphere of 85°C and 90% humidity for 1000 hours, and then its optical properties were measured. The visible light transmittance was 80.9%, the average transmittance at wavelengths of 800nm ​​to 1000nm was 37.7%, and the haze was 1.2%. The change in visible light transmittance due to exposure to the humid and hot atmosphere was 1.7%, and the change in the average transmittance at wavelengths of 800nm ​​to 1000nm was 5.1%, both of which were larger than those of the Examples. The change in haze was 0.2%. The manufacturing conditions are shown in Table 1, and the evaluation results are shown in Table 2.

[0133] As in Example 1, a thin-sectioned sample of the infrared-absorbing sheet according to Comparative Example 1 was prepared using a microtome and observed using a transmission electron microscope, resulting in a TEM image of the infrared-absorbing particles shown in Figure 4(a), an elemental mapping image of tungsten atoms in the same field of view as that of (a) shown in (b), and an elemental mapping image of aluminum atoms in the same field of view as that of (a) shown in (c). As is clear from Figures 4(a), (b), and (c), it can be seen that the deterioration inhibitor containing aluminum atoms is not present in large amounts in the microscopic vicinity of the infrared-absorbing particles containing tungsten atoms, and the deterioration inhibitor is present almost uniformly throughout the entire field of view.

[0134] [Table 1] [Table 2]

Claims

1. The present invention comprises infrared absorbing fine particles and one or more deterioration inhibitors selected from the group consisting of hydrolysis products of metal chelate compounds, hydrates of metal oxides, and metal oxides, the deterioration inhibitor is a powder or fine particles, the deterioration inhibitor is disposed in the microscopic vicinity of the infrared-absorbing fine particles, The phrase "the deterioration inhibitor is disposed in the microscopic vicinity of the infrared absorbing fine particles" means that, in the infrared absorbing fine particles and in a region of 50 nm or less surrounding the infrared absorbing fine particles, the deterioration inhibitor in contact with the infrared absorbing fine particles and the deterioration inhibitor not in contact with the infrared absorbing fine particles are disposed at a higher density than in other regions; The infrared absorbing fine particles are tungsten oxide fine particles represented by the general formula WyOz (wherein W is tungsten, O is oxygen, and 2.2≦z / y≦2.999), or / and tungsten oxide fine particles represented by the general formula MxWyOz (wherein M is H, He, an alkali metal, an alkaline earth metal, a rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al , Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb, W is tungsten, O is oxygen, 0.001≦x / y≦1, 2.0≦z / y≦3.0).

2. 2. The infrared absorbing fine particle powder according to claim 1, wherein the deterioration inhibitor contains one or more metal elements selected from the group consisting of Al, Zr, Ti, Si and Zn.

3. 3. An infrared absorbing fine particle powder dispersion liquid, comprising the infrared absorbing fine particle powder according to claim 1 or 2 dispersed in a predetermined liquid solvent.

4. 4. The infrared absorbing fine particle powder dispersion according to claim 3, wherein the liquid solvent is one or more liquid solvents selected from the group consisting of organic solvents, oils and fats, liquid plasticizers, compounds that are polymerized by curing, and water.

5. 3. An infrared absorbing fine particle dispersion, comprising the infrared absorbing fine particle powder according to claim 1 or 2 dispersed in a predetermined solid resin.

6. 6. The infrared absorbing nanoparticle dispersion according to claim 5, wherein the solid resin is one or more resins selected from the group consisting of fluororesin, PET resin, acrylic resin, polyamide resin, vinyl chloride resin, polycarbonate resin, olefin resin, epoxy resin, and polyimide resin.

7. The infrared absorbing microparticle powder dispersion according to claim 3 or 4 is a dried and solidified infrared absorbing microparticle powder dispersion further containing a dispersant, The infrared absorbing microparticle dispersion is a powdery dispersion in which the infrared absorbing microparticle powder is dispersed in a solid medium which is a dried and solidified product of the dispersant.

8. 7. The infrared absorbing nanoparticle dispersion according to claim 5, The visible light transmittance of the infrared absorbing nanoparticle dispersion is set to 80%; When the infrared absorbing nanoparticle dispersion is exposed to a humid and hot atmosphere at a temperature of 85°C and a relative humidity of 90% for 1000 hours, the amount of change in the average value of light transmittance in the wavelength range of 800 nm to 1000 nm before and after the exposure is 1.8% or less.

9. 2. A method for producing the infrared absorbing fine particle powder according to claim 1, a step of mixing the infrared absorbing nanoparticles with water or a water-soluble solvent and dispersing the mixture to obtain an infrared absorbing nanoparticle dispersion; a step of mixing the metal chelate compound with a liquid solvent containing water to obtain a deterioration inhibitor-containing liquid; a step of adding the deterioration inhibitor-containing liquid to the infrared absorbing nanoparticle dispersion while stirring the infrared absorbing nanoparticle dispersion to obtain an infrared absorbing nanoparticle dispersion containing the deterioration inhibitor; and a step of drying the infrared absorbing nanoparticle dispersion liquid containing the deterioration inhibitor to remove the liquid solvent, thereby obtaining infrared absorbing nanoparticle powder.

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