Infrared absorbing particles, infrared absorbing particle dispersion, infrared absorbing particle dispersion

Abstract

To provide an infrared absorption particle having photochromic properties.SOLUTION: An infrared absorption particle contains one or more selected from tungsten oxide having oxygen deficiency and composite tungsten oxide, and has a BET specific surface area of 200 m2 / g or less and a crystallite diameter of 60 nm or less, with the product of the BET specific surface area and the crystallite diameter being 1350 m2 nm / g or more and 2500 m2 nm / g or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to infrared absorbing particles, an infrared absorbing particle dispersion, and an infrared absorbing particle dispersion. [Background technology]

[0002] Various technologies have been proposed so far as solar radiation shading technologies that reduce solar radiation transmittance while maintaining transparency by having good visible light transmittance. Among them, solar radiation shading technologies using infrared absorbing fine particles or dispersions of such infrared absorbing fine particles have advantages over other technologies, such as superior solar radiation shading properties, low cost, radio wave transmittance, and high weather resistance.

[0003] In Patent Document 1, the inventors of the present invention proposed an infrared-shielding material microparticle dispersion in which infrared-shielding material microparticles are dispersed in a medium, the infrared-shielding material microparticles containing tungsten oxide microparticles and / or composite tungsten oxide microparticles, and the particle diameter of the infrared-shielding material microparticles is 1 nm or more and 800 nm or less.

[0004] The infrared-shielding material microparticle dispersion disclosed in Patent Document 1 exhibits excellent visible light transmittance and infrared-shielding properties, and Patent Document 1 also discloses an example in which the solar radiation transmittance is as extremely low as 36% when the visible light transmittance is 70%. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2005 / 037932 Summary of the Invention [Problem to be solved by the invention]

[0006] By applying the infrared shielding material fine particle dispersion disclosed in Patent Document 1 to, for example, window materials, it becomes possible to selectively shield infrared rays contained in sunlight and reduce the cooling load in summer.

[0007] However, in response to the recent increase in environmental awareness toward carbon neutrality, there is a demand for further reduction in the environmental load caused by air conditioning and the like. For this reason, it is sometimes necessary to actively transmit visible light and infrared rays contained in sunlight so as to reduce not only the cooling load in summer but also, for example, the heating load in winter. In other words, there is a demand for materials whose infrared-shielding properties can be changed depending on the situation, such as the season, and for example, there is a demand for infrared-shielding materials whose infrared-shielding properties are variable, i.e., that have chromic properties.

[0008] Therefore, one aspect of the present invention aims to provide infrared absorbing particles having photochromic properties. [Means for solving the problem]

[0009] In one aspect of the present invention, a tungsten oxide composition containing at least one selected from a tungsten oxide having an oxygen deficiency and a composite tungsten oxide is provided. BET specific surface area is 200m 2 / g or less, and the crystallite diameter is 60 nm or less, The product of BET specific surface area and crystallite diameter is 1350m 2 ·nm / g or more 2500m 2 nm / g or less the law of nature, The absorbance at a wavelength of 1300 nm changes by 20% or more after 20 minutes of UV irradiation. , infrared absorbing particles are provided. [Effects of the Invention]

[0010] In one aspect of the present invention, infrared absorbing particles with photochromic properties can be provided. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram of the hexagonal crystal structure of composite tungsten oxide. [Figure 2] FIG. 2 is an explanatory diagram of the infrared absorbing particle dispersion liquid. [Figure 3] FIG. 3 is an explanatory diagram of an infrared absorbing particle dispersion. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention. [Infrared absorbing particles] The present inventors have investigated infrared absorbing particles having photochromic properties, and have found that infrared absorbing particles having high infrared absorbing properties and photochromic properties can be obtained by controlling the particle size, shape, and crystallinity of the infrared absorbing particles, specifically the BET specific surface area and crystallite diameter, and have thus completed the present invention.

[0013] The infrared absorbing particles of this embodiment may contain one or more tungsten oxides selected from tungsten oxides having oxygen deficiency and composite tungsten oxides. The infrared absorbing particles of this embodiment may have a BET specific surface area of ​​200 m 2 / g or less, crystallite diameter of 60 nm or less, the product of BET specific surface area and crystallite diameter of 1350 m 2 ·nm / g or more 2500m 2 nm / g or less.

[0014] The infrared absorbing particles of this embodiment can have photochromic properties, that is, properties in which the color tone and light absorption properties change when irradiated with light of a specific wavelength.

[0015] As described above, the infrared absorbing particles of this embodiment can contain a tungsten oxide-based material that is one or more types selected from tungsten oxide having oxygen deficiency and composite tungsten oxide. Note that the infrared absorbing particles of this embodiment can also be composed of one or more types selected from tungsten oxide having oxygen deficiency (hereinafter sometimes simply referred to as "tungsten oxide") and composite tungsten oxide.

[0016] Tungsten oxide and composite tungsten oxide, like other hydrated tungsten oxides, are photochromic and electrochromic materials.

[0017] Tungsten oxides and composite tungsten oxides can be used as electrochromic materials because a light absorption region is created by inserting cationic species such as lithium through electrical action.

[0018] On the other hand, the infrared absorbing particles of this embodiment utilize a photochromic reaction that occurs in response to high-energy light such as ultraviolet light or visible light. Furthermore, when the threshold of the energy required for the reaction is low, the particles also respond to infrared light and exhibit a photochromic reaction.

[0019] In tungsten oxide-based photochromic materials, the light absorption region is created by adsorbing cationic species such as protons generated around infrared-absorbing particles in response to ultraviolet light, visible light, etc., onto the infrared-absorbing particles. For this reason, it is important for tungsten oxide-based photochromic materials to have an increased surface area so that more cationic species can be adsorbed. It is also important to increase the crystallinity so that the generation of the light absorption region due to the adsorption of cationic species can be further increased.

[0020] Examples of sources of protons that respond to ultraviolet light, visible light, or the like include organic substances, such as additives such as dispersants, surfactants, and coupling agents described below, and resins used as solid media for infrared absorbing particle dispersions. (1) BET specific surface area, crystallite size The infrared absorbing particles of this embodiment have a BET specific surface area of ​​200 m 2 / g or less, crystallite diameter of 60 nm or less, the product of BET specific surface area and crystallite diameter of 1350 m 2 ·nm / g or more 2500m 2 nm / g or less.

[0021] Generally, the higher the BET specific surface area, the more cationic species generated in response to ultraviolet light, visible light, etc. can be adsorbed, resulting in stronger photochromic properties. Also, the larger the crystallite size, the higher the crystallinity of the infrared-absorbing particles, which enhances the light-absorbing function and increases the infrared absorption properties.

[0022] However, assuming spherical particles, there is a trade-off between BET specific surface area and crystallite size, making it difficult to achieve both photochromic properties and infrared absorption by increasing both parameters. Therefore, the shape of infrared-absorbing particles should be far from spherical, and preferably be scaly or needle-like with a high aspect ratio. Furthermore, it is preferable for the surface to have large irregularities, and it is preferable to increase the load during the grinding and dispersion process aimed at microparticulation to generate these irregularities.

[0023] If the infrared absorbing particles are spherical particles, that is, if they are assumed to be spherical particles, the product of the BET specific surface area and the crystallite diameter is 1000 m 2 It will be about nm.

[0024] On the other hand, the product of the BET specific surface area and the crystallite diameter is 1350m 2 ·nm / g or more 2500m 2 By setting the specific surface area to 1.420 m / g or less, the particle size is significantly different from a spherical shape, and the surface irregularities are sufficiently generated, achieving both photochromic properties and infrared absorption properties. The product of the BET specific surface area and the crystallite diameter is 1420 m 2 ·nm / g or more 2500m 2It is more preferable that the crystallite diameter is 60 nm or less. However, if the crystallite diameter is too high, the haze (cloudiness) caused by light scattering of the infrared absorbing particles themselves will increase, which may cause problems in window material applications that require visible light transparency. Therefore, the crystallite diameter is preferably 60 nm or less. Although there is no particular restriction on the lower limit of the crystallite diameter, it is preferably 1 nm or more, and more preferably 10 nm or more.

[0025] In addition, from the viewpoint of ease of industrial production, the BET specific surface area is 200 m 2 The lower limit of the BET specific surface area is preferably 10 m / g or less. 2 / g or more, and 25m 2 / g or more is more preferable.

[0026] The infrared absorbing particles of this embodiment contain one or more types selected from tungsten oxides having oxygen deficiencies and composite tungsten oxides, and satisfy the above-mentioned requirements for the BET specific surface area and crystallite size, thereby providing infrared absorbing particles with excellent infrared absorbing properties and photochromic properties.

[0027] The BET specific surface area can be measured by a gas adsorption method using a fully automatic specific surface area measuring device (such as Macsorb manufactured by Mountec Co., Ltd.). The crystallite size can be calculated by measuring an X-ray diffraction pattern by powder X-ray diffraction (θ-2θ method) using a powder X-ray diffractometer (such as X'Pert-PRO / MPD manufactured by PANalytical, Spectris Co., Ltd.) and analyzing it by the Rietveld method. When attempting to visually define the crystallite size, there are various definition methods such as the major axis diameter, minor axis diameter, and unidirectional diameter for scaly particles and needle-like particles. However, since the crystallite size in this embodiment is calculated by analysis using the X-ray diffraction pattern and the Rietveld method, it is not visually defined but is crystallographically defined. (2) Photochromic properties The photochromic properties of the infrared absorbing particles of this embodiment are not particularly limited, but for example, it is preferable that the rate of change in absorbance at a wavelength of 1300 nm after 20 minutes of UV (ultraviolet) light irradiation is 20% or more. That is, it is preferable that the rate of change in absorbance at a wavelength of 1300 nm after 20 minutes of UV light irradiation is 20% or more.

[0028] The rate of change before and after ultraviolet irradiation can be calculated, for example, by the following formula (1): In the following formula (1), all absorbances refer to absorbance at a wavelength of 1300 nm. (Rate of change) = 100 × [(absorbance after UV irradiation) - (absorbance before UV irradiation)] ÷ (absorbance before UV irradiation) (1) The photochromic properties of infrared absorbing particles, i.e., the rate of change in absorbance, vary depending on the wavelength, irradiation intensity, and irradiation time of the irradiated UV. Therefore, when measuring the rate of change in absorbance, a mercury lamp with a dominant wavelength of 365 nm was used as the UV source, and the irradiation intensity was 100 mW / cm. 2 It is also preferable to keep the irradiation time constant, for example, 20 minutes as described above.

[0029] Furthermore, when evaluating the absorbance of infrared-absorbing particles before and after ultraviolet irradiation, a film-, sheet-, or board-shaped infrared-absorbing particle dispersion containing infrared-absorbing particles is produced, and its transmittance can be measured using a spectrophotometer such as the U-4100 manufactured by Hitachi, Ltd. Then, the absorbance of the infrared-absorbing particles can be calculated using the transmittance. In this case, it is preferable to use a dispersion of the same film thickness that does not contain infrared-absorbing particles as the baseline for the transmittance, and to measure only the infrared-absorbing particle component as much as possible. (3) Tungsten oxide and composite tungsten oxide contained in infrared absorbing particles As described above, the infrared absorbing particles of this embodiment can contain one or more types selected from tungsten oxides having oxygen deficiencies and composite tungsten oxides. (3-1) Tungsten oxide Tungsten oxide, specifically tungsten oxide having oxygen deficiency, can be represented by the general formula W y O z (wherein W is tungsten, O is oxygen, and 2.2≦z / y≦2.999) is preferred. y O z In the tungsten oxide represented by the formula (1), the composition range of tungsten and oxygen is preferably such that the composition ratio of oxygen to tungsten (z / y) is less than 3. That is, the tungsten oxide may have oxygen deficiencies. As described above, the composition ratio of oxygen to tungsten (z / y) is preferably 2.2≦z / y≦2.999, more preferably 2.45≦z / y≦2.999, and even more preferably 2.60≦z / y≦2.999.

[0030] If the z / y value is 2.2 or more, it is possible to avoid the appearance of undesired WO2 crystalline phases in the tungsten oxide, and high photochromic properties can be obtained by the intensive grinding and dispersion treatment described below, making the infrared absorbing particles particularly effective. Furthermore, by making the z / y value preferably less than 3, more preferably 2.999 or less, a particularly sufficient number of free electrons are generated to enhance the absorption and reflection properties in the infrared region, making it possible to obtain efficient infrared absorbing particles.

[0031] Furthermore, the so-called "Magnéli phase" having a composition ratio expressed as 2.45≦z / y≦2.999 has excellent absorption properties for light in the near-infrared region, and is therefore more preferably used as an infrared absorbing material. For this reason, it is more preferable that the value of z / y is 2.45≦z / y≦2.999, as described above. (3-2) Composite tungsten oxide Composite tungsten oxide is obtained by adding the element M, which will be described later, to the above-mentioned tungsten oxide (WO3). By adding element M to tungsten oxide to form composite tungsten oxide, free electrons are generated in the WO3, and strong absorption characteristics resulting from the free electrons are expressed, particularly in the near-infrared region, making it effective as an infrared absorbing particle for wavelengths around 1000 nm.

[0032] That is, by using a composite tungsten oxide in which the control of the oxygen amount and the addition of an element M that generates free electrons are used in combination with respect to WO3, more efficient infrared absorption characteristics can be exhibited. A composite tungsten oxide in which the control of the oxygen amount and the addition of an element M that generates free electrons are used in combination with respect to WO3 has the general formula M x W y O z and can be expressed as such. In the general formula, it is preferable that x, y, and z satisfy the relationship of 0.001 ≦ x / y ≦ 1 and 2.4 < z / y ≦ 3.0. M in the general formula represents the element M, W represents tungsten, and O represents oxygen, respectively.

[0033] As described above, when the value of x / y indicating the addition amount of the element M is 0.001 or more, a particularly sufficient amount of free electrons is generated in the composite tungsten oxide, and a high infrared absorption effect can be obtained. And the larger the addition amount of the element M, the more the supply amount of free electrons increases and the infrared absorption efficiency also increases, but the effect also saturates when the value of x / y is about 1. Further, when the value of x / y is 1 or less, it is preferable because the generation of an impurity phase in the infrared absorption particles containing the composite tungsten oxide can be avoided.

[0034] Note that the element M is preferably one or more 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, Yb.

[0035] General formula M x W y O zFrom the perspective of particularly enhancing the stability in the composite tungsten oxide represented by [formula], 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, Re. And for the infrared absorbing particles containing the composite tungsten oxide, from the perspective of improving optical properties and weather resistance, element M is more preferably one or more elements selected from alkaline earth metal elements, transition metal elements, Group 4B elements, and Group 5B elements.

[0036] Regarding the value of z / y indicating the oxygen addition amount, in the composite tungsten oxide represented by the general formula M x W y O z In addition to the same mechanism as that of the tungsten oxide represented by the above-mentioned W y O z working, at z / y = 3.0, there is also the supply of free electrons due to the addition amount of the above-mentioned element M. Also, if 2.4 < z / y, high photochromic properties can be obtained by the strong pulverization and dispersion treatment described later, so 2.4 < z / y ≦ 3.0 is preferable, and 2.45 ≦ z / y ≦ 3.0 is more preferable.

[0037] Furthermore, when the composite tungsten oxide has a hexagonal crystal structure, the light transmission in the visible light region of the infrared absorbing particles containing the composite tungsten oxide is improved, and the light absorption in the infrared region is improved. Therefore, the infrared absorbing particles of the present embodiment preferably contain a hexagonal crystal structure. This will be described while referring to FIG. 1 which is a schematic plan view of this hexagonal crystal structure. FIG. 1 shows a projection view when the crystal structure of the composite tungsten oxide having a hexagonal crystal structure is viewed from the (001) direction.

[0038] In Fig. 1, six octahedra 11 formed by WO6 units are assembled to form a hexagonal void, and element 12, which is element M, 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 improve light transmission in the visible light region and light absorption in the infrared region, it is sufficient that the composite tungsten oxide contains the unit structure explained with reference to Fig. 1, and the composite tungsten oxide may be crystalline or amorphous. However, the higher the crystallinity, the better the light absorption characteristics.

[0039] When cations of element M are added and present in the above-mentioned 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, the hexagonal crystal is easily formed when one or more elements selected from Cs, K, Rb, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn are added as the element M. 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.

[0040] In order for the composite tungsten oxide having a hexagonal crystal structure to have a uniform crystal structure, the amount of element M added is preferably such that the value of x / y in the general formula described above is 0.2 or more and 0.5 or less, more preferably 0.33. It is believed that when the value of x / y is 0.33, the element M described above is arranged in all of the hexagonal voids.

[0041] In addition, infrared-absorbing particles containing composite tungsten oxides other than hexagonal crystals, such as tetragonal and cubic crystals, also have sufficiently effective infrared absorption. The absorption position in the infrared region tends to change depending on the crystal structure, with the absorption position tending to shift toward longer wavelengths in the order of cubic crystals < tetragonal crystals < hexagonal crystals. Concomitantly, the order of least absorption of light in the visible region is hexagonal, tetragonal, and cubic crystals. Therefore, for applications requiring greater transmission of light in the visible region and greater shielding of light in the infrared region, it is preferable to use a 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.

[0042] The surfaces of the infrared absorbing particles may be coated with an oxide containing one or more of Si, Ti, Zr, Al, and Zn. By coating with such an oxide, the weather resistance of the infrared absorbing particles can be improved. Although the coating method is not particularly limited, the surfaces of the infrared absorbing particles can be coated by adding an alkoxide of the above-mentioned metal to a solution in which the infrared absorbing particles are dispersed. [Method of manufacturing infrared absorbing particles] Next, a method for producing infrared absorbing particles according to this embodiment will be described. Since the method for producing infrared absorbing particles according to this embodiment can produce the infrared absorbing particles already described, some overlapping descriptions will be omitted.

[0043] The method for producing the infrared absorbing particles of the present embodiment is not particularly limited, but may include a pulverization step of pulverizing infrared absorbing particles containing one or more selected from tungsten oxides having oxygen deficiencies and composite tungsten oxides.

[0044] In the pulverization process, one or more powders selected from tungsten oxide powder and composite tungsten oxide powder, which are to be pulverized into infrared-absorbing particles, are prepared, along with a liquid medium and, if necessary, other additives such as a dispersant, surfactant, and coupling agent. These are then mixed to form a slurry. This slurry is then introduced into a pulverization processing device, where the powder is pulverized to form infrared-absorbing particles, which are then dispersed in the liquid medium. In other words, by performing the pulverization process, an infrared-absorbing particle dispersion liquid, which will be described later, is obtained. For this reason, the pulverization process can also be referred to as a pulverization-dispersion process.

[0045] In the method for producing infrared absorbing particles according to the present embodiment, it is preferable to apply a strong load to the infrared absorbing particles during pulverization in order to activate the surfaces of the particles and enhance their photochromic properties. Therefore, it is preferable to use, as the pulverization treatment device, devices such as a bead mill, a ball mill, a sand mill, a paint shaker, or an ultrasonic homogenizer. Among these, it is more preferable to use, as the pulverization treatment device, a media-agitating mill such as a bead mill, a ball mill, a sand mill, or a paint shaker, which uses a medium such as beads, balls, or Ottawa sand.

[0046] However, because it is preferable that the energy applied during the milling and dispersion treatment results in the milled infrared-absorbing particles being uniformly dispersed in the dispersion liquid without agglomeration, it is preferable not to apply too much load during the milling process. Particular attention is paid to the selection of milling media and milling conditions. Specifically, it is preferable to use fine milling media with an outer diameter (ball diameter) of 0.09 mm or less and perform the milling and dispersion treatment under a high load at a milling media speed of 15 m / s or more. By performing the milling process under such milling conditions, infrared-absorbing particles with the desired properties can be easily produced. Furthermore, a bead mill such as the Star Mill ZRS manufactured by Ashizawa Finetech Co., Ltd. is a preferred example of an apparatus capable of performing the milling and dispersion treatment under such conditions.

[0047] When dispersing infrared-absorbing particles in a plasticizer, an organic solvent having a boiling point of 120°C or less may be added as necessary. Specific examples of organic solvents having a boiling point of 120°C or less include toluene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, isopropyl alcohol, and ethanol. Any organic solvent can be selected as long as it has a boiling point of 120°C or less and can uniformly disperse infrared-absorbing particles.

[0048] After the pulverization step is completed, the liquid medium may be removed as needed to recover the infrared absorbing particles. The method for removing the liquid medium is not particularly limited, and the liquid medium can be removed, for example, by drying under reduced pressure. [Infrared absorbing particle dispersion] The infrared absorbing particle dispersion liquid of this embodiment can contain a liquid medium and the above-described infrared absorbing particles disposed in the liquid medium.

[0049] The liquid medium can be one or more selected from water, organic solvents, oils and fats, liquid resins, liquid plasticizers for plastics, and polymeric monomers.

[0050] The infrared absorbing particles of this embodiment can take the form of an infrared absorbing particle dispersion during processing, for example, when they are made into an infrared absorbing particle dispersion or the like.

[0051] For example, as shown in FIG. 2, the infrared absorbing particle dispersion 20 of this embodiment can contain the infrared absorbing particles 21 described above and a liquid medium 22, and the infrared absorbing particles 21 are preferably dispersed in the liquid medium 22. Note that FIG. 2 is a schematic diagram, and the infrared absorbing particle dispersion of this embodiment is not limited to this form. For example, although the infrared absorbing particles 21 are depicted as spherical particles in FIG. 2, the shape of the infrared absorbing particles 21 is not limited to this form and can have any shape, such as the aforementioned scale-like or needle-like shape. The infrared absorbing particles 21 can also have, for example, a coating on their surfaces. In addition to the infrared absorbing particles 21 and the liquid medium 22, the infrared absorbing particle dispersion 20 can also contain other additives as needed.

[0052] (1) Ingredients contained in the infrared absorbing particle dispersion Hereinafter, each component contained in the infrared absorbing particle dispersion liquid of this embodiment will be described. (1-1) Infrared absorbing particles As the infrared absorbing particles, the infrared absorbing particles already described can be used, and therefore a description thereof will be omitted here.

[0053] The content of the infrared absorbing particles contained in the infrared absorbing particle dispersion liquid of this embodiment is not particularly limited, but is preferably, for example, from 0.01% by mass to 80% by mass.

[0054] This is because a content of the infrared absorbing particles of 0.01% by mass or more can provide sufficient infrared shielding properties, and a content of the infrared absorbing particles of 80% by mass or less can easily disperse the infrared absorbing particles in a liquid medium. (1-2) Liquid medium The liquid medium may be, for example, one or more selected from water, organic solvents, oils and fats, liquid resins, liquid plasticizers for plastics, and polymeric monomers. (organic solvent) Examples of the organic solvent include alcohol-based, ketone-based, ester-based, glycol-based, amide-based, and hydrocarbon-based organic solvents.

[0055] Specifically, alcoholic 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.

[0056] 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. (Oils and fats) Examples of oils and fats include vegetable oils and fats, plant-derived compounds, and petroleum-based solvents.

[0057] 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 oil; and non-drying oils such as olive oil, coconut oil, palm oil, and dehydrated castor oil.

[0058] Examples of compounds derived from vegetable oils include fatty acid monoesters and ethers obtained by directly esterifying fatty acids of vegetable oils with monoalcohols.

[0059] Commercially available petroleum-based solvents can also be used as oils and fats.

[0060] Examples of 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). (liquid resin) As the liquid resin, for example, one or more types selected from liquid acrylic resin, liquid epoxy resin, liquid polyester resin, liquid urethane resin, etc. can be used. (liquid plasticizer) Examples of plasticizers for liquid plastics include plasticizers that are compounds of monohydric alcohols and organic acid esters, ester-based plasticizers such as polyhydric alcohol organic acid ester compounds, and phosphoric acid-based plasticizers such as organic phosphoric acid-based plasticizers. Preferably, all of these are liquid at room temperature.

[0061] Among them, 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 decylic acid.

[0062] Other examples include ester compounds of tetraethylene glycol or tripropylene glycol with a monobasic organic compound.

[0063] 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. (polymer monomer) Examples of the polymer monomer include monomers and oligomers that form polymers by polymerization, etc. Specific examples include methyl methacrylate monomers, acrylate monomers, and styrene resin monomers.

[0064] The liquid medium described above may be used alone or in combination of two or more. If necessary, the pH may be adjusted by adding an acid or alkali to the liquid medium. (1-3) Other additives The infrared absorbing particle dispersion liquid of this embodiment may contain other additives, such as a dispersant, a surfactant, a coupling agent (hereinafter, sometimes referred to as a "compound such as a dispersant"), etc. The compound such as a dispersant can further improve the dispersion stability of the infrared absorbing particles and suppress an increase in light scattering and haze due to re-aggregation.

[0065] The dispersant or other compound preferably has one or more functional groups selected from an amine-containing group, a hydroxyl group, a carboxyl group, a sulfo group, and an epoxy group. These functional groups adsorb to the surface of the infrared-absorbing particles to prevent aggregation and particularly promote uniform dispersion. The dispersant or other compound is more preferably a polymeric dispersant having one of the above functional groups in its molecule. Furthermore, these additives, which are dispersants or other compounds, often act as surface modifiers for the infrared-absorbing particles of this embodiment, and can therefore be organic substances that supply protons in response to visible light or ultraviolet light. Furthermore, dispersants that have a low glass transition temperature and are liquid at room temperature can be used as a substitute for the liquid medium described in the previous section, i.e., as a liquid medium.

[0066] Acrylic-styrene copolymer dispersants having functional groups are also preferred dispersants. Among these, acrylic-styrene copolymer dispersants having a carboxyl group as a functional group and acrylic dispersants having an amine-containing group as a functional group are more preferred. Dispersants having an amine-containing group as a functional group preferably have a molecular weight Mw of 2000 to 200,000 and an amine value of 5 mgKOH / g 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 mgKOH / g to 50 mgKOH / g.

[0067] 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, 28000, 31845, 32000, 32500, 3 2550, 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) D510, 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, 166, 167, 168, 170, 171, 174, 180, 181, 182, 183, 184, 185, 19 0, 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, P 9065, P9080, 051, 052, 053, 054, 055, 057, 063, 065, 066N, 067A, 077, 088, 141, 220S, 300, 302, 306, 30 7, 310, 315, 320, 322, 323, 325, 330, 331, 333, 337, 340, 345, 346, 347, 348, 350, 354, 355, 358N, 361N, 3 70, 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, Dynwet800, Siclean3700, UV3500, UV3510, UV3570 etc; EFKA Additives (registered trademark) 2020, 2025, 3030, 3031, 3236, 4008, 4009, 4010, 4015, 4020, 4046, 4047, 4050, 4055, 4060, 4080, 4300, 4310, 4320, 4330, 4340, 4400, 4401, 4402, 4403, 4500, 5066, 5220, 6220, 6225, 6230, 6700, 6780, 6782, 7462, 8503, etc. JONCRYL (registered trademark) (hereinafter the same) 67, 678, 586, 611, 680, 682, 690, 819, -JDX5050, etc., manufactured by BASF Japan Ltd.; TERPLUS (registered trademark) (hereinafter the same) MD1000, D1180, D1130, etc. manufactured by Otsuka Chemical Co., Ltd.; Ajinomoto Fine-Techno Co., Inc., AJISPER (registered trademark) (hereinafter the same) PB-711, PB-821, PB-822, etc.; 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, and the like, manufactured by Kusumoto Chemicals Co., Ltd.; Alphon (registered trademark) (hereinafter the same) UH-2170, UC-3000, UC-3910, UC-3920, UF-5022, UG-4010, UG-4035, UG-4040, UG-4070, and Reseda (registered trademark) (hereinafter the same) GS-1015, GP-301, GP-301S, etc., manufactured by Toagosei Co., Ltd. Examples include Mitsubishi Chemical Corporation's Dianale (registered trademark) BR-50, BR-52, BR-60, BR-73, BR-80, BR-83, BR-85, BR-87, BR-88, BR-90, BR-96, BR-102, BR-113, and BR-116. (2) Uses of infrared absorbing particle dispersion liquid The use of the infrared absorbing particle dispersion liquid of this embodiment is not particularly limited, and it can be used for various purposes that require, for example, infrared absorbing properties or chromic properties.

[0068] The dispersion liquid of the present embodiment can be used as an infrared absorbing substrate by, for example, applying it to the surface of an appropriate substrate to form a dispersion film. The dispersion film is a type of infrared absorbing particle dispersion and a type of dried and solidified product of the infrared absorbing particle dispersion liquid.

[0069] Furthermore, the infrared absorbing particle dispersion liquid of this embodiment containing a compound such as the dispersant described above can be dried and, if necessary, pulverized to form a powdered infrared absorbing particle dispersion (sometimes referred to as a "dispersed powder" in this specification). In other words, the dispersed powder is a type of infrared absorbing particle dispersion, and also a type of dried and solidified infrared absorbing particle dispersion liquid. The dispersed powder is a powdered dispersion in which infrared absorbing particles are dispersed in a solid medium such as a dispersant. Because the dispersed powder contains a dispersant, the infrared absorbing particles can be easily redispersed in an appropriate medium by mixing it with the medium.

[0070] The dispersed powder can also be used as a raw material for adding the infrared absorbing particles in a dispersed state to an infrared absorbing product. That is, the dispersed powder in which the infrared absorbing particles of this embodiment 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 and used as an infrared absorbing particle dispersion, as described below.

[0071] The infrared absorbing particle dispersion liquid of this embodiment can be used in various applications that utilize light-to-heat conversion.

[0072] For example, a curable ink composition can be prepared by adding an infrared-absorbing particle dispersion to an uncured thermosetting resin, or by adding an uncured thermosetting resin to an infrared-absorbing particle dispersion. The curable ink composition contains the infrared-absorbing particles described above, which function as an auxiliary agent that increases the amount of heat generated by irradiation with electromagnetic waves such as infrared rays. Because the curable ink composition contains a thermosetting resin, the infrared-absorbing particles function as an auxiliary agent that increases the amount of heat generated by irradiation with electromagnetic waves such as infrared rays, as described above, and the thermosetting resin can be cured. By providing the curable ink composition on, for example, a substrate, it is possible to increase the adhesion between the cured product of the curable ink composition and the substrate when irradiated with electromagnetic waves such as infrared rays.

[0073] Therefore, in addition to being used as a conventional ink, the curable ink composition can also be suitably used in applications such as stereolithography, in which a three-dimensional object is formed by repeatedly applying a coating and curing it by irradiating it with electromagnetic waves such as infrared rays.

[0074] Alternatively, a thermoplastic resin-containing ink composition can be obtained by adding the infrared absorbing particles of this embodiment to a heat-melted thermoplastic resin, or by dispersing the infrared absorbing particles of this embodiment in an appropriate solvent and then adding a thermoplastic resin that is highly soluble in the solvent.

[0075] For example, by applying a thermoplastic resin-containing ink composition to a substrate and irradiating it with electromagnetic waves such as infrared rays, the solvent is removed and the resin is heat-fused, allowing the cured product of the thermoplastic resin-containing ink composition to adhere to the substrate. In this case, in the thermoplastic resin-containing ink composition, as in the case of the curable ink composition described above, the infrared-absorbing particles function as an auxiliary agent that increases the amount of heat generated by irradiation with electromagnetic waves such as infrared rays.

[0076] Therefore, in addition to its use as a conventional ink, the thermoplastic resin-containing ink composition can also be suitably used in applications such as photolithography, which involves repeatedly applying a coating, removing the solvent by irradiating with electromagnetic waves such as infrared rays, and heat-fusing the resin to form a three-dimensional object.

[0077] Furthermore, when an infrared-absorbing particle dispersion liquid is dropped onto a spread of thermoplastic resin powder, or immediately thereafter, electromagnetic waves such as infrared rays can be irradiated to remove the solvent and heat-fuse the resin, allowing the cured product to adhere to a substrate or form a three-dimensional object.

[0078] The following are some examples of how photochromic properties can be utilized in various applications that utilize these photothermal conversions. When photothermal conversion function is required, the photothermal conversion properties can be improved by irradiating with ultraviolet light immediately before or at the same time. This means that the function can be achieved with a smaller amount of additive than before. Furthermore, when the function is not required, the infrared absorption properties can be reduced, which also reduces the visible light absorption properties. This can further improve the transparency and whiteness of objects that adhere to substrates or three-dimensional objects.

[0079] The curable ink composition and the thermoplastic resin-containing ink composition described above are also examples of the infrared absorbing particle dispersion liquid of this embodiment. [Infrared absorbing particle dispersion] The infrared absorbing particle dispersion of this embodiment can contain a solid medium and the above-described infrared absorbing particles disposed in the solid medium.

[0080] For example, as shown in FIG. 3 , an infrared absorbing particle dispersion 30 of this embodiment can contain the above-described infrared absorbing particles 31 and a solid medium 32, and the infrared absorbing particles 31 are preferably dispersed in the solid medium 32. Note that FIG. 3 is a schematic diagram, and the infrared absorbing particle dispersion of this embodiment is not limited to this form. For example, while the infrared absorbing particles 31 are depicted as spherical particles in FIG. 3 , the shape of the infrared absorbing particles 31 is not limited to this form and can have any shape, such as the above-described scale-like or needle-like shape. The infrared absorbing particles 31 can also have, for example, a coating on their surfaces. In addition to the infrared absorbing particles 31 and the solid medium 32, the infrared absorbing particle dispersion 30 can also contain other additives as needed.

[0081] The infrared absorbing particle dispersion (hereinafter also referred to as "dispersion") can be produced, for example, by processing the above-mentioned infrared absorbing particle dispersion liquid. (1) Ingredients contained in the infrared absorbing particle dispersion Hereinafter, each component contained in the infrared absorbing particle dispersion of this embodiment will be described. (1-1) Infrared absorbing particles As the infrared absorbing particles, the infrared absorbing particles already described can be used, and therefore a description thereof will be omitted here.

[0082] The proportion of infrared-absorbing particles contained in the dispersion of this embodiment is not particularly limited and can be selected as desired depending on the thickness and the optical and mechanical properties required of the dispersion. The amount of filler relative to the solid medium, i.e., the blending ratio of infrared-absorbing particles, is preferably 50% by mass or less relative to the solid medium. When the content ratio of infrared-absorbing particles relative to the solid medium is 50% by mass or less, aggregation of the infrared-absorbing particles in the solid medium can be particularly suppressed, and particularly good transparency can be maintained. Furthermore, the amount of infrared-absorbing particles used can be controlled, which is advantageous in terms of cost.

[0083] The lower limit of the content ratio of the infrared-absorbing particles relative to the solid medium is not particularly limited, but is preferably, for example, 0.00001% by mass or more. Even if the content ratio is reduced, the desired infrared-shielding performance can be achieved by increasing the thickness of the infrared-absorbing particle dispersion. However, since window materials are often used in thicknesses of 100 cm or less, particularly high infrared-shielding performance can be achieved by setting the content ratio of the infrared-absorbing particles relative to the solid medium to 0.00001% by mass or more. (1-2) Solid medium The solid medium is preferably a medium resin, that is, a resin can be suitably used as the solid medium.

[0084] The medium resin is not particularly limited, but is preferably any one selected from the group consisting of polyethylene terephthalate resin, polycarbonate resin, acrylic resin, styrene resin, polyamide resin, polyethylene resin, vinyl chloride resin, olefin resin, epoxy resin, polyimide resin, fluororesin, ethylene-vinyl acetate copolymer resin, and polyvinyl acetal resin; a mixture of two or more resins selected from the above group; and a copolymer of two or more resins selected from the above group. (2) Shape, thickness, etc. The shape and thickness of the dispersion of this embodiment can be selected arbitrarily depending on the intended use and are not particularly limited. When the dispersion of this embodiment is formed, for example, as an optical component for solar radiation shielding, a transparent resin can be used as the solid medium, and the thickness can be, for example, 0.1 μm or more and 50 mm or less. As described above, the shape of the dispersion of this embodiment is not particularly limited, but it can be in the form of a sheet, board, or film. The dispersion may also be configured as a filter formed on the surface of a transparent substrate such as glass, a resin board, a resin sheet, or a resin film. (3) Uses of infrared absorbing particle dispersions The use of the infrared absorbing particle dispersion of this embodiment is not particularly limited, and it can be used in various applications where infrared absorbing properties or chromic properties are required, for example.

[0085] The dispersion of this embodiment can be suitably used, for example, in window materials in various buildings and vehicles, intended to sufficiently let in visible light while blocking light in the infrared region, thereby suppressing an increase in indoor temperature while maintaining brightness. This reduces the cooling load in summer. The following examples are possible examples of utilizing photochromic properties. Because of the shorter hours of sunlight in winter, the infrared absorption properties of infrared-absorbing particles are reduced compared to summer. At this time, the visible light absorption properties are also reduced. Therefore, more visible light and infrared rays contained in sunlight can be let into the room, thereby reducing the heating load in winter. Of course, if no material is used in window materials, etc., maximum sunlight can be let in, but in that case, the cooling load in summer will increase significantly. In other words, compared to conventional infrared-shielding materials that do not have photochromic properties, the heating load in winter can be further reduced, thereby further reducing annual energy consumption.

[0086] The dispersion of this embodiment can be used in a PDP (plasma display panel) and is suitable for use in filters that block infrared rays emitted forward from the PDP. The photochromic properties can be utilized in the following cases, for example. When an infrared blocking function is required, the situation is often one in which light from the sun or indoor electric lights is irradiated, and therefore the infrared absorption properties of the infrared-absorbing particles can be improved. This allows the function to be achieved with a smaller amount added than before. Furthermore, when this function is not required, the infrared absorption properties can be reduced, but in this case, the visible light absorption properties also decrease. This allows the transparency of filters and the like to be further improved.

[0087] Furthermore, because infrared-absorbing particles have absorption in the infrared region, when an infrared laser is irradiated onto a printed surface containing the infrared-absorbing particles, they absorb infrared rays having a specific wavelength. Therefore, an anti-counterfeit printed material obtained by printing an anti-counterfeit ink containing these infrared-absorbing particles on one or both sides of a printed substrate can be irradiated with infrared rays having a specific wavelength and the reflection or transmission thereof measured, thereby determining the authenticity of the printed material from the difference in the amount of reflection or transmission. Furthermore, because infrared-absorbing particles do not absorb in the visible region, the printed material appears white or transparent except when authenticity is being determined, thereby concealing the presence of the infrared-absorbing particles. The photochromic properties can be utilized in the following examples: By irradiating the printed material with ultraviolet light immediately before or simultaneously with infrared authentication, infrared absorption characteristics can be improved, resulting in more advanced authentication. In other words, the printed material cannot be read by infrared light alone; it can only be read by irradiating it with ultraviolet light. Furthermore, while infrared absorption characteristics are reduced outside of authentication times, visible light absorption characteristics are also reduced at this time. That is, the anti-counterfeit printed matter appears more transparent or white except when authenticity is being determined, thereby further concealing the presence of the infrared absorbing particles. The anti-counterfeit printed matter is an example of an infrared absorbing particle dispersion.

[0088] Furthermore, a photothermal conversion layer can be formed by mixing an infrared-absorbing particle dispersion with a binder component to prepare an ink, applying the ink to a substrate, drying the applied ink, and then curing the dried ink. This photothermal conversion layer can generate heat only at the desired location with high positional precision when irradiated with an electromagnetic laser such as infrared light, making it 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 electroluminescent elements using a laser transfer method, thermal paper for thermal printers, or ink ribbons for thermal transfer printers. The photochromic properties can be utilized in the following cases: When photothermal conversion function is required, ultraviolet light can be irradiated immediately before or simultaneously to improve the photothermal conversion properties. This allows the function to be achieved with a smaller additive amount than conventional methods. Furthermore, when this function is not required, the infrared absorption properties can be reduced, but this also reduces the visible light absorption properties. This can further improve the transparency and whiteness of donor sheets, thermal paper, and ink ribbons. The light-to-heat conversion layer is an example of an infrared absorbing particle dispersion.

[0089] Infrared-absorbing fibers can also be obtained by dispersing infrared-absorbing particles in a suitable medium and incorporating the dispersion into one or more portions selected from the surface and interior of the fiber. 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. At the same time, the fiber transmits visible light, resulting in an infrared-absorbing fiber with excellent design. As a result, it can be used in a variety of applications, including textile products requiring heat retention, such as cold weather clothing, sportswear, stockings, and curtains, as well as other industrial textile products. The photochromic properties can be utilized in the following examples: When moisture retention is required, most people are active outdoors, and sunlight is radiating immediately before or at the same time, improving the infrared absorption properties of the infrared-absorbing particles. This allows the fiber to perform its function with a smaller additive amount than conventionally. Furthermore, when this function is not required, the infrared absorption properties can be reduced, but this also reduces the visible light absorption properties. This can further improve the whiteness and design properties of textile products. Furthermore, by using infrared-absorbing fibers with photochromic properties in a part of a textile product, it is possible to clearly show the change in absorption characteristics when irradiated with sunlight or to make characters stand out. Therefore, this part can be used as a moisture-retaining indicator or mark. The infrared-absorbing fibers are an example of an infrared-absorbing particle dispersion.

[0090] The infrared-absorbing particle dispersion of this embodiment can also be applied to materials used for the roofs and exterior walls of agricultural and horticultural greenhouses. It can be used as an insulating material for agricultural and horticultural facilities, providing thermal insulation by transmitting visible light to ensure the light necessary for photosynthesis of plants in the greenhouse while efficiently absorbing other light, such as near-infrared light contained in sunlight. The photochromic properties can be utilized in the following cases, for example: When thermal insulation is required, sunlight is often irradiated, and the infrared absorption properties of the infrared-absorbing particles are improved. Therefore, the function can be achieved with a smaller amount than conventionally added. Furthermore, when this function is not required, the infrared absorption properties can be reduced, but at the same time, the visible light absorption properties are also reduced. Therefore, the transparency of the insulating material can be further improved. Furthermore, when considering the daily cycle, the photochromic properties work more favorably. Because sunlight is not irradiated at night, the absorption properties are reduced, and the transparency of the insulating material is improved. In the morning, when the temperature does not rise as much, thermal insulation is not required as much, but at this time, the high transparency of the thermal insulation material can maximize the amount of photosynthesis by plants. As the temperature rises toward noon, thermal insulation becomes necessary. At this time, the infrared absorption characteristics have already been increased by sunlight irradiation from the morning, and thermal insulation is improved. In other words, when thermal insulation is not required, the thermal insulation material should be as transparent as possible to increase the amount of photosynthesis by plants. The thermal insulation material for agricultural and horticultural facilities is an example of an infrared-absorbing particle dispersion.

[0091] The infrared absorbing particle dispersion of this embodiment can also be sandwiched between transparent substrates (transparent base materials) to form an infrared absorbing laminated transparent base material.

[0092] The transparent substrate is not particularly limited and can be arbitrarily selected in consideration of visible light transmittance, etc. For example, the transparent substrate can be one or more types selected from glass plates, plastic plates, plastic boards, plastic films, etc. It is preferable that the transparent substrate is transparent in the visible light region.

[0093] When a transparent plastic substrate is used, the plastic material is not particularly limited and can be selected depending on the application, and polycarbonate resin, acrylic resin, polyethylene terephthalate resin, polyamide resin, vinyl chloride resin, olefin resin, epoxy resin, polyimide resin, fluororesin, etc. can be used.

[0094] In addition, two or more transparent substrates can be used as the infrared-absorbing laminated transparent substrate of this embodiment, and when two or more transparent substrates are used, for example, transparent substrates made of different materials can be used in combination as the constituent transparent substrates. In addition, the thicknesses of the constituent transparent substrates do not need to be the same, and transparent substrates of different thicknesses can be used in combination.

[0095] In the infrared absorbing laminated transparent substrate of this embodiment, the above-described infrared absorbing particle dispersion can be used as an intermediate layer.

[0096] Furthermore, the above-described infrared-absorbing particle dispersion can be used to form a coating layer containing infrared-absorbing particles on a transparent substrate (transparent substrate) selected from a film substrate and a glass substrate, and by such an operation, an infrared-absorbing film or an infrared-absorbing glass, which is an infrared-absorbing transparent substrate, can be produced.

[0097] The coating layer can be prepared using a coating liquid obtained by mixing the above-mentioned infrared absorbing particle dispersion liquid with a plastic or a monomer, for example.

[0098] For example, the infrared absorbing film can be prepared as follows.

[0099] A coating liquid is obtained by adding a medium resin that becomes a solid medium after curing to the above-mentioned infrared-absorbing particle dispersion liquid. After this coating liquid is coated on the surface of a film substrate, the liquid medium contained in the coating liquid is evaporated. Then, by curing the medium resin using a method appropriate for the medium resin used, a coating layer (coating film) in which the infrared-absorbing particles are dispersed in the solid medium is formed, and an infrared-absorbing film can be obtained.

[0100] In addition, infrared absorbing glass can be similarly produced by using a glass substrate as the transparent substrate.

[0101] The medium resin of the coating layer can be selected depending on the purpose from, for example, UV-curable resins, thermosetting resins, electron beam-curable resins, room temperature-curable resins, thermoplastic resins, etc. Specific examples of the medium resin include polyethylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polystyrene resin, polypropylene resin, ethylene-vinyl acetate copolymer, polyester resin, polyethylene terephthalate resin, fluororesin, polycarbonate resin, acrylic resin, polyvinyl butyral resin, etc.

[0102] These medium resins may be used alone or in combination, but among the medium resins for the coating layer, it is particularly preferable to use a UV-curable resin binder from the viewpoints of productivity, equipment costs, etc.

[0103] It is also possible to use binders that use metal alkoxides. Typical examples of such metal alkoxides include alkoxides of Si, Ti, Al, and Zr. Binders that use these metal alkoxides can be hydrolyzed and condensed by heating, etc., to form a coating layer in which the solid medium is an oxide film.

[0104] Materials for the above-mentioned film substrate can be selected from polyester, acrylic, urethane, polycarbonate, polyethylene, ethylene-vinyl acetate copolymer, vinyl chloride, fluororesin, etc. depending on various purposes. However, as the film substrate of the infrared absorbing film, a polyester film is preferred, and a polyethylene terephthalate (PET) film is more preferred.

[0105] In addition, to facilitate adhesion of the coating layer, the surface of the film substrate is preferably surface-treated. Furthermore, to improve adhesion between the glass substrate or film substrate and the coating layer, it is also preferable to form an intermediate layer on the glass substrate or film substrate and then form the coating layer on the intermediate layer. The configuration of the intermediate layer is not particularly limited, and it can be composed of, for example, a polymer film, a metal layer, an inorganic layer (e.g., an inorganic oxide layer such as silica, titania, or zirconia), an organic / inorganic composite layer, or the like.

[0106] The method for providing a coating layer on a film substrate or a glass substrate is not particularly limited as long as it can uniformly apply the infrared absorbing particle dispersion onto the surface of the substrate, and examples thereof include bar coating, gravure coating, spray coating, and dip coating.

[0107] As described above, the infrared absorbing particle dispersion of the present embodiment has chromic properties. Therefore, when used for the various applications described above, the optical properties can be changed by irradiation with ultraviolet light, visible light, or the like as necessary, to provide an infrared absorbing particle dispersion having optical properties suited to the application. [Method for producing infrared absorbing particle dispersion] Next, a method for producing the infrared absorbing particle dispersion of this embodiment will be described. Since the method for producing the infrared absorbing particle dispersion of this embodiment can produce the infrared absorbing particle dispersion described above, some overlapping descriptions will be omitted.

[0108] The method for producing the infrared absorbing particle dispersion of this embodiment is not particularly limited, and the dispersion can be produced by any method.

[0109] The infrared absorbing particle dispersion of this embodiment can be produced, for example, by mixing a solid medium or a raw material thereof with the above-described infrared absorbing particles, molding the mixture into a desired shape, and then curing the mixture.

[0110] The infrared absorbing particle dispersion can also be produced using, for example, the above-described infrared absorbing particle dispersion liquid.

[0111] When an infrared absorbing particle dispersion is used for production, the method for producing the dispersion of this embodiment can include, for example, a mixing step of first mixing the infrared absorbing particle dispersion described above with a solid medium. It is also possible to remove the solvent from the mixture of the infrared absorbing particle dispersion and the solid medium obtained in the mixing step, thereby producing a powdery or pellet-like dispersion in which the infrared absorbing particles are temporarily dispersed in the solid medium. The powdery or pellet-like dispersion may be further mixed with a resin, if necessary.

[0112] The resulting mixture can then be melt mixed at a temperature near the melting point of the resin, which is the solid medium (around 100°C to 400°C), and molded to form a dispersion.

[0113] Alternatively, the dispersion may be processed into a powder or pellet form to prepare a so-called masterbatch, which may then be molded into a film, sheet, or board by various methods, such as extrusion molding, inflation molding, solution casting, or the like.

[0114] Alternatively, for example, an infrared absorbing particle dispersion for forming a coating film can be prepared by mixing the infrared absorbing particle dispersion with a liquid medium such as an organic solvent (e.g., alcohol) or water, a resin serving as a binder, and, if desired, an additive such as a surfactant (coating liquid preparation step).The infrared absorbing particle dispersion for forming a coating film can then be applied to a suitable substrate surface, and then the liquid medium can be removed or the resin serving as a binder can be cured, thereby forming a dispersion on the substrate surface.

[0115] For example, the infrared absorbing particle dispersion thus produced can be disposed between a plurality of transparent substrates to form the above-described infrared absorbing laminated transparent substrate. [Example]

[0116] The present invention will be specifically described below with reference to examples, although the present invention is not limited to the following examples. [Example 1] (Preparation of infrared absorbing particles and infrared absorbing particle dispersion) In Example 1, first, 2.16 g of Cs2CO3 was dissolved in 3.3 g of water, and this was added to 10 g of H2WO4 and thoroughly stirred, and then dried to obtain a mixed powder with the target composition of Cs / W (molar ratio) = 0.33.

[0117] The mixed powder was heated in a supply of 0.6% by volume of H gas with N gas as a carrier, and reduced at 550°C for 3 hours. It was then fired in a N gas atmosphere at 800°C for 1 hour. Through these operations, the cesium tungsten bronze powder having a hexagonal crystal structure according to Example 1 was obtained.

[0118] The crystal structure of cesium tungsten bronze, i.e., composite tungsten oxide, was identified by measuring the X-ray diffraction pattern by powder X-ray diffraction (θ-2θ method) using Cu-Kα radiation with a Spectris X'Pert-PRO / MPD device.

[0119] The resulting cesium tungsten bronze was chemically analyzed for W (tungsten) by inductively coupled plasma (ICP) optical emission spectroscopy (ICP-OES). Furthermore, O was analyzed by using a light element analyzer (LECO, Model ON-836) to melt the sample in He gas and quantify the CO gas that reacted with carbon in the crucible using IR absorption spectroscopy. The results confirmed that the O / W (molar ratio) of the resulting cesium tungsten bronze was 2.5. In other words, the resulting cesium tungsten bronze contained Cs 0.33 WO 2.5 We were able to confirm that this is the case.

[0120] A mixed liquid (slurry) obtained by mixing 10% by mass of the cesium tungsten bronze powder according to Example 1 with 90% by mass of water was placed in a bead mill (Star Mill ZRS manufactured by Ashizawa Finetech Co., Ltd.) together with φ0.07 mm ZrO2 beads and subjected to a pulverization and dispersion treatment for 40 hours (pulverization step). Thereafter, the slurry was taken out once to obtain infrared absorbing particles according to Example 1 containing cesium tungsten bronze as a main component and an infrared absorbing particle dispersion according to Example 1 containing the same.

[0121] Next, the obtained infrared absorbing particle dispersion liquid according to Example 1 was placed in a vacuum dryer (LCV-234 manufactured by Espec), the solvent was evaporated, and only the infrared absorbing particles were taken out. The drying temperature was 70°C, and the drying time was 24 hours. The BET specific surface area was measured by a gas adsorption method using a fully automatic specific surface area measuring device (Macsorb manufactured by Mountec Co., Ltd.), and was found to be 62 m 2 The gas used for adsorption was nitrogen gas.

[0122] In addition, the X-ray diffraction pattern of the extracted infrared absorbing particles was measured by powder X-ray diffraction (θ-2θ method) using a powder X-ray diffractometer (X'Pert-PRO / MPD manufactured by PANalytical, Spectris Co., Ltd.), and the crystallite diameter was calculated by Rietveld analysis, which was found to be 23 nm. Therefore, the product of the BET specific surface area and the crystallite diameter was 1426 m 2 nm / g. (Preparation of Infrared-Absorbing Particle Dispersion) A water-soluble ultraviolet curable resin and an ethanol solvent were added to and mixed with the infrared absorbing particle dispersion liquid obtained according to Example 1, and the mixture was applied to a glass substrate having a thickness of 3 mm using a bar coater (IMC-700 manufactured by Imoto Machinery Co., Ltd.) to form a coating film. Next, the solvent was evaporated from the obtained coating film, and then the coating film was cured by irradiating it with ultraviolet light for 1 minute. By the above operations, an infrared absorbing particle dispersion according to Example 1 was obtained.

[0123] At this time, the infrared absorbing particles turned blue due to their photochromic properties after one minute of irradiation with ultraviolet light, so the dispersion was left to stand in a dark place in the atmosphere for one day to discolor it, thereby obtaining an infrared absorbing particle dispersion according to Example 1. Here, the ultraviolet curable resin is the solid medium of the infrared absorbing particle dispersion, and generates protons in response to visible light or ultraviolet light.

[0124] The transmittance of the decolorized infrared-absorbing particle dispersion was measured at 5 nm intervals using a spectrophotometer (Hitachi U-4100) in the wavelength range of 200 nm to 2600 nm. The baseline was a 3 mm thick glass substrate coated and cured with a UV-curable resin film of the same thickness that did not contain infrared-absorbing particles, and the transmittance of the infrared-absorbing particle component alone was measured. The transmittance was 92.1% at a wavelength of 500 nm and 34.8% at a wavelength of 1300 nm, and the absorbance at 1300 nm was 0.458. These results confirmed the high visible light transparency and infrared absorption. (Evaluation of photochromic properties) Next, UV irradiation was carried out for 20 minutes using a UV conveyor device (ECS-401GX, manufactured by Eye Graphics) to color the infrared absorbing particle dispersion according to Example 1. At this time, a mercury lamp having a dominant wavelength of 365 nm was used as the UV source in the UV conveyor device, and the UV irradiation intensity was 100 mW / cm. 2The transmittance was then measured using a spectrophotometer in the same manner as before irradiation. It was 89.7% at a wavelength of 500 nm and 27.1% at a wavelength of 1300 nm, confirming high visible light transparency and infrared absorption. The absorbance at a wavelength of 1300 nm was 0.567, a change in absorbance of 24%.

[0125] [Comparative Example 1] A mixed liquid (slurry) obtained by mixing 10% by mass of the cesium tungsten bronze powder according to Example 1 with 90% by mass of water was placed in a bead mill (Star Mill ZRS manufactured by Ashizawa Finetech Co., Ltd.) together with φ0.3 mm ZrO2 beads and subjected to a pulverization and dispersion treatment for 10 hours (pulverization step). Thereafter, the slurry was removed once to obtain infrared absorbing particles according to Comparative Example 1 containing cesium tungsten bronze as a main component, and an infrared absorbing particle dispersion according to Comparative Example 1 containing the same.

[0126] Next, the obtained infrared absorbing particle dispersion liquid according to Comparative Example 1 was placed in a vacuum dryer (LCV-234 manufactured by Espec), the solvent was evaporated, and only the infrared absorbing particles were taken out. The drying temperature was 70°C, and the drying time was 24 hours. Then, the BET specific surface area and the crystallite diameter were measured, and they were found to be 44 m 2 / g and 23nm, the product of which is 1012m 2 nm / g.

[0127] An infrared absorbing dispersion according to Comparative Example 1 was obtained in the same manner as in Example 1, except that the infrared absorbing particle dispersion according to Comparative Example 1 was used. Evaluation was then performed in the same manner as in Example 1, and the transmittance was 91.9% at a wavelength of 500 nm and 34.6% at a wavelength of 1300 nm, and the absorbance at a wavelength of 1300 nm was 0.461. Furthermore, after UV irradiation, the transmittance was 89.3% at a wavelength of 500 nm and 28.9% at a wavelength of 1300 nm, and the absorbance at a wavelength of 1300 nm was 0.539. At this time, the rate of change in absorbance was 17%. [Explanation of symbols]

[0128] 20 Infrared absorbing particle dispersion 21, 31 Infrared absorbing particles 22 Liquid Media 32 Solid medium

Claims

1. The tungsten oxide contains at least one material selected from a tungsten oxide having an oxygen deficiency and a composite tungsten oxide, BET specific surface area is 200m ２ / g or less, and the crystallite diameter is 60 nm or less, The product of the BET specific surface area and the crystallite diameter is 1350 m ２ ・nm / g or more 2500m ２ nm / g or less, Infrared absorbing particles whose absorbance at a wavelength of 1,300 nm changes by 20% or more after 20 minutes of UV irradiation.

2. The tungsten oxide having oxygen deficiency is represented by the general formula W ｙ O ｚ (wherein W is tungsten, O is oxygen, and 2.2≦z / y≦2.999), The composite tungsten oxide is represented by the general formula M ｘ W ｙ O ｚ 2. The infrared absorbing particle according to claim 1, wherein M is 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; W is tungsten; O is oxygen; and 0.001≦x / y≦1, 2.4<z / y≦3.

0.

3. 3. The infrared absorbing particle according to claim 1, which comprises a hexagonal crystal structure.

4. A liquid medium; The infrared absorbing particles according to any one of claims 1 to 3, which are disposed in the liquid medium; The liquid medium is at least one selected from the group consisting of water, organic solvents, oils and fats, liquid resins, liquid plasticizers for plastics, and polymer monomers.

5. 5. The infrared absorbing particle dispersion liquid according to claim 4, wherein the content of the infrared absorbing particles is 0.01% by mass or more and 80% by mass or less.

6. a solid medium; An infrared absorbing particle dispersion comprising the infrared absorbing particles according to claim 1 disposed in the solid medium.

7. 7. The infrared absorbing particle dispersion according to claim 6, wherein the solid medium is a medium resin.

8. 8. The infrared absorbing particle dispersion according to claim 7, wherein the medium resin is any one selected from the group consisting of polyethylene terephthalate resin, polycarbonate resin, acrylic resin, styrene resin, polyamide resin, polyethylene resin, vinyl chloride resin, olefin resin, epoxy resin, polyimide resin, fluororesin, ethylene-vinyl acetate copolymer resin, and polyvinyl acetal resin; a mixture of two or more resins selected from the group; and a copolymer of two or more resins selected from the group.

9. The infrared absorbing particle dispersion according to any one of claims 6 to 8, which has a sheet-like, board-like or film-like shape.

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