JP7371638B2 - Surface-treated infrared absorbing fine particle dispersion and method for producing the same - Google Patents

Description

The present invention relates to a surface-treated infrared-absorbing fine particle dispersion in which surface-treated infrared-absorbing fine particles are dispersed in a solvent containing water, and a method for producing the same.

In recent years, the demand for infrared absorbers has increased rapidly, and many proposals regarding infrared absorbers have been made.
Let's look at these proposals from a functional perspective. For example, in the field of window materials for various buildings and vehicles, the aim is to block out light in the near-infrared region while allowing in sufficient visible light, thereby maintaining brightness and suppressing indoor temperature rises. There is something like that.

As a prior art document, for example, Patent Document 1 discloses that a layer selected from the group consisting of Group IIIa, Group IVa, Group Vb, Group VIb, and Group VIIb of the periodic table is placed on a transparent glass substrate as the first layer from the substrate side. A composite tungsten oxide film containing at least one kind of metal ion is provided, a transparent dielectric film is provided as a second layer on the first layer, and a third layer is formed from group IIIa of the periodic table. A composite tungsten oxide film containing at least one metal ion selected from the group consisting of IVa group, Vb group, VIb group, and VIIb group is provided, and the refractive index of the second transparent dielectric film is set to Infrared-shielding glass that can be suitably used in areas that require high visible light transmittance and good infrared-shielding performance by having a refractive index lower than that of the composite tungsten oxide films of the first layer and the third layer. is proposed.

In Patent Document 2, a first dielectric film is provided as a first layer on a transparent glass substrate from the substrate side, and a tungsten oxide film is formed as a second layer on the first layer using the same method as in Patent Document 1. An infrared shielding glass has been proposed in which a second dielectric film is provided as a third layer on the second layer.

In Patent Document 3, a composite tungsten oxide film containing the same metal element as in Patent Document 1 is provided as a first layer on a transparent glass substrate from the substrate side by a method similar to Patent Document 1, and then A heat ray blocking glass has been proposed in which a transparent dielectric film is provided as a second layer.

In Patent Document 4, tungsten trioxide (WO ₃ ), molybdenum trioxide (MoO ₃ ), niobium pentoxide (Nb ₂ O ₅ ), tantalum pentoxide ( A metal oxide film selected from one or more of Ta ₂ O ₅ ), vanadium pentoxide (V ₂ O ₅ ), and vanadium dioxide (VO ₂ ) is coated by a CVD method or a spray method, and then heated at about 250°C. A solar control glass sheet with solar shielding properties has been proposed, which is formed by pyrolysis at

Patent Document 5 proposes a solar variable dimming insulation material using tungsten oxide obtained by hydrolyzing tungstic acid and adding an organic polymer with a specific structure called polyvinylpyrrolidone to the tungsten oxide. . When the sunlight variable dimming insulation material is irradiated with sunlight, the ultraviolet rays in the light are absorbed by tungsten oxide, generating excited electrons and holes, and a small amount of ultraviolet rays causes a significant amount of pentavalent tungsten to appear. As the coloring reaction increases, the coloring reaction becomes faster, and the coloring density increases accordingly. On the other hand, when light is blocked, the pentavalent tungsten is very quickly oxidized to hexavalent tungsten, increasing the decoloring reaction. Using this coloring/decoloring characteristic, the coloring and decoloring reaction to sunlight is fast, and when coloring, an absorption peak appears at a wavelength of 1250 nm in the near-infrared region, making it possible to block the near-infrared rays of sunlight. It is proposed that a heat insulating material is obtained.

On the other hand, the present inventors have disclosed in Patent Document 6 that by dissolving tungsten hexachloride in alcohol and directly evaporating the medium, or heating under reflux, evaporating the medium, and then heating at 100°C to 500°C. disclosed obtaining tungsten oxide fine particle powder consisting of tungsten trioxide, its hydrate, or a mixture of both. They also disclosed that an electrochromic device can be obtained using the tungsten oxide fine particles, and that the optical properties of the film can be changed when a multilayer laminate is formed and protons are introduced into the film. .

Patent Document 7 discloses that a mixed aqueous solution of meta-ammonium tungstate and various water-soluble metal salts is used as a raw material, and a dried product of the mixed aqueous solution is heated at a heating temperature of about 300 to 700°C, and during this heating, an inert By supplying hydrogen gas to which gas (addition amount; approximately 50 vol% or more) or water vapor (addition amount; approximately 15 vol% or less) _is added, the general formula _M Methods for producing various tungsten bronzes represented by metal elements such as 0<x<1 have been proposed. It has been proposed that this operation be carried out on a support to produce various tungsten bronze coated composites for use as electrode catalyst materials for fuel cells and the like.

In Patent Document 8, the present inventors disclosed an infrared shielding material fine particle dispersion in which infrared shielding material fine particles are dispersed in a medium, and the optical properties, conductivity, and manufacturing method of the infrared shielding material fine particle dispersion. . The infrared shielding material fine particles are tungsten oxide fine particles expressed by the general formula WyOz (where W is tungsten, O is oxygen, 2.2≦z/y≦2.999), or/and the general formula MxWyOz (However, M is H, He, alkali metal, alkaline earth metal, 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, W is tungsten, O is oxygen, 0.001≦x/y≦1, 2.2≦z/y≦3.0) Composite tungsten oxide fine particles expressed by the following, and the particle diameter of the infrared shielding material fine particles is 1 nm or more and 800 nm or less.

Japanese Patent Application Publication No. 8-59300 Japanese Unexamined Patent Publication No. 8-12378 Japanese Patent Application Publication No. 8-283044 Japanese Patent Application Publication No. 2000-119045 Japanese Patent Application Publication No. 9-127559 Japanese Patent Application Publication No. 2003-121884 Japanese Patent Application Publication No. 8-73223 International Publication No. 2005/37932 International Publication No. 2010/55570

The present inventors used the infrared shielding material fine particle dispersion according to Patent Document 8 for use in vehicles and building materials, and shielded light in the near-infrared region while sufficiently incorporating visible light from the light contained in sunlight. The aim was to suppress the rise in indoor temperature while maintaining brightness. At this time, in order to obtain the infrared shielding material fine particle dispersion according to Patent Document 8, for example, an infrared absorbing material fine particle dispersion liquid in which infrared absorbing material fine particles are dispersed in a solvent is prepared, and a resin or the like is added to the infrared absorbing material fine particle dispersion liquid. A method may be adopted in which the coating liquid is dissolved to form a coating liquid, and the coating liquid is dried after being applied or sprayed onto a base material, for example.

However, according to the studies of the present inventors, optical members (transparent substrates, films, resin sheets, etc.) containing the above-mentioned tungsten oxide fine particles and/or composite tungsten oxide fine particles may be exposed to air depending on the usage conditions and method. It has been found that water vapor and moisture in the optical member gradually penetrate into the coating layer and solid resin of the optical member. When water vapor or moisture penetrates into the coating layer or solid resin, the surface of the tungsten oxide fine particles and/or composite tungsten oxide fine particles decomposes, and the transmittance of light with a wavelength of 200 to 2600 nm decreases over time. It has been found that there is a problem in that the infrared absorption characteristics of the optical member gradually decrease. In particular, it has been found that the higher the surface activity of tungsten oxide fine particles or composite tungsten oxide fine particles, the greater the rate of loss of infrared absorption properties due to the decomposition and deterioration.
In the present invention, the term "coating layer" refers to a medium film that is solid at room temperature and is formed on a substrate to a predetermined thickness by, for example, coating or spraying.

Under the above-mentioned circumstances, the present inventors disclosed in Patent Document 9 that tungsten oxide represented by the general formula WyOz and/or the general formula Composite tungsten oxide fine particles expressed as MxWyOz, the average primary particle size of the fine particles is 1 nm or more and 800 nm or less, and the surface of the fine particles is a tetrafunctional silane compound or a hydrolysis product thereof, and/or Infrared-shielding fine particles coated with an organometallic compound and a method for producing the same are disclosed.

The tungsten oxide fine particles and/or composite tungsten oxide fine particles according to Patent Document 9 described above had excellent moisture resistance. However, infrared absorbing materials used for vehicles and building materials are used for long periods of time under various environments including high humidity and high temperature environments. As demands in the market have increased year by year, improvements in heat and humidity resistance have been required for the infrared shielding fine particles disclosed in Patent Document 9. Furthermore, in recent years, there has been a demand for reducing the environmental impact of various industrial materials, and the above-mentioned coating liquids are required to contain no organic solvents that have a high environmental impact, and preferably have water as the main solvent. It is being That is, there is a need for an infrared absorbing fine particle dispersion liquid that is dispersed in a solvent containing water.

The present invention was made under the above circumstances, and its object is to provide a surface-treated infrared-absorbing fine particle dispersion in which surface-treated infrared-absorbing fine particles having excellent heat and humidity resistance are dispersed in a water-containing solvent. , and a manufacturing method thereof.

In order to solve the above-mentioned problems, the present inventors used infrared-absorbing fine particles with excellent optical properties, and created a structure that allows the infrared-absorbing fine particles to improve their chemical stability even in high-humidity and high-temperature environments. We conducted research on As a result, by using a compound that has excellent affinity with the surface of the infrared absorbing fine particles, and which uniformly adsorbs to the surface of each individual particle of the infrared absorbing fine particles to form a strong coating film, We realized that it is important to coat the surface of the infrared absorbing fine particles.

The present inventors continued their research and came up with a metal chelate compound or a metal cyclic oligomer compound as a compound that has excellent affinity for the above-mentioned infrared absorbing fine particles and forms a coating film. As a result of further research, it was found that the hydrolysis products of these compounds or the polymers of the hydrolysis products produced when the metal chelate compounds and metal cyclic oligomer compounds are hydrolyzed are infrared absorbing fine particles. It was found that this compound uniformly adsorbs to the surfaces of individual particles and forms a strong coating film.

That is, the surface of the infrared absorbing fine particles is a product of hydrolysis of a metal chelate compound, a polymer of a hydrolysis product of a metal chelate compound, a hydrolysis product of a metal cyclic oligomer compound, a hydrolysis product of a metal cyclic oligomer compound. Infrared absorbing fine particles (sometimes referred to as "surface-treated infrared absorbing fine particles" in the present invention) that are uniformly and strongly coated with a coating film containing one or more selected from polymers This is what I did. It was also discovered that the surface-treated infrared absorbing fine particles maintain their infrared absorbing properties even when exposed to high humidity and high temperature environments.

The present inventors further continued their research and came up with a surface-treated infrared-absorbing fine particle dispersion liquid in which the surface-treated infrared-absorbing fine particles are dispersed in a solvent containing water, resulting in the present invention.

That is, the invention for solving the above problems is:
A surface-treated infrared-absorbing fine particle dispersion liquid in which surface-treated infrared-absorbing fine particles are dispersed in a solvent containing water,
The surface-treated infrared absorbing fine particles have a surface containing a hydrolyzed product of a metal chelate compound, a polymer of a hydrolyzed product of a metal chelate compound, a hydrolyzed product of a metal cyclic oligomer compound, or a metal cyclic oligomer compound. is coated with a coating film containing one or more selected from the following:
The surface-treated infrared-absorbing fine particle dispersion is characterized in that the surface-treated infrared-absorbing fine particles have a dispersed particle diameter of 20 nm or more and 400 nm or less.
Furthermore, the invention for solving the above-mentioned problems is
A step of dispersing infrared absorbing fine particles in a solvent containing water to obtain an aqueous dispersion for forming a coating film; and adding a metal chelate compound and/or a metal cyclic oligomer compound to the aqueous dispersion for forming a coating film; The surface of the absorption fine particles is made of a hydrolysis product of a metal chelate compound, a polymer of a hydrolysis product of a metal chelate compound, a hydrolysis product of a metal cyclic oligomer compound, a polymer of a hydrolysis product of a metal cyclic oligomer compound. A step of obtaining a surface-treated infrared-absorbing fine particle dispersion in which the surface-treated infrared-absorbing fine particles are dispersed in a solvent containing water by coating the surface-treated infrared-absorbing fine particles with a coating film containing one or more of the selected types. A method for producing a surface-treated infrared absorbing fine particle dispersion, comprising:

According to the present invention, it is possible to obtain a dispersion of surface-treated infrared-absorbing fine particles in which surface-treated infrared-absorbing fine particles that maintain excellent infrared absorption characteristics even when exposed to high humidity and high temperature environments are dispersed in a water-containing solvent. Ta.

FIG. 2 is a schematic plan view of the crystal structure of a composite tungsten oxide having a hexagonal crystal structure.

The surface-treated infrared-absorbing fine particle dispersion according to the present invention has surface-treated infrared-absorbing fine particles dispersed in a solvent containing water.
The surface-treated infrared-absorbing fine particles according to the present invention have surfaces of the infrared-absorbing fine particles containing a hydrolyzed product of a metal chelate compound, a polymer of a hydrolyzed product of a metal chelate compound, a hydrolyzed product of a metal cyclic oligomer compound, etc. , a polymer of a hydrolysis product of a metal cyclic oligomer compound. The dispersed particle diameter in the dispersion liquid is 20 nm or more and 400 nm or less. Further, the infrared absorbing fine particles are preferably tungsten oxide fine particles and/or composite tungsten oxide fine particles.

Hereinafter, the surface-treated infrared absorbing fine particle dispersion according to the present invention will be described as [1] infrared absorbing fine particles, [2] a surface treatment agent for infrared absorbing fine particles, [3] a method for surface treatment of infrared absorbing fine particles, [4] a dispersion solvent, [5] Surface-treated infrared absorbing fine particle dispersion according to the present invention will be explained in detail in this order.
In addition, in the present invention, "in order to impart heat and humidity resistance to infrared absorbing fine particles, a hydrolysis product of a metal chelate compound, a polymer of a hydrolysis product of a metal chelate compound, a metal cyclic oligomer compound is added to the surface of the fine particles. A coating film formed using one or more selected from hydrolysis products of metal cyclic oligomer compounds and polymers of hydrolysis products of metal cyclic oligomer compounds may be simply referred to as a "coating film."

[1] Infrared absorbing fine particles The infrared absorbing fine particles used in the surface-treated infrared absorbing fine particle dispersion according to the present invention have the general formula WyOz (where W is tungsten, O is oxygen, and 2.2≦z/y≦2.999. ), or/and the general formula MxWyOz (where M is H, He, alkali metal, alkaline earth metal, 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, One or more elements selected from V, Mo, Ta, Re, Be, Hf, Os, Bi, I, Yb, W is tungsten, O is oxygen, 0.001≦x/y≦1, 2 The infrared absorbing particles are preferably infrared absorbing fine particles expressed by the following formula: .0≦z/y≦3.0).

Infrared absorbing fine particles will be described below using tungsten oxide fine particles and composite tungsten oxide fine particles as examples.
In general, it is known that materials containing free electrons exhibit a reflection/absorption response to electromagnetic waves around the solar radiation region with a wavelength of 200 nm to 2600 nm due to plasma vibration. It is known that when powder of such a substance is made into particles smaller than the wavelength of light, geometric scattering in the visible light region (wavelengths from 380 nm to 780 nm) is reduced and transparency in the visible light region can be obtained.
In the present invention, "transparency" is used to mean "less scattering and high transparency for light in the visible light region."

Generally, tungsten oxide (WO ₃ ) does not have effective free electrons, so it has poor absorption/reflection properties in the infrared region and is not effective as an infrared absorbing fine particle. However, by forming WO ₃ with oxygen vacancies or composite tungsten oxide in which a positive element such as Na is added to WO ₃ , free electrons are generated in the tungsten oxide or composite tungsten oxide, and the infrared region It is known that absorption characteristics derived from free electrons appear in Analysis of single crystals of materials containing these free electrons suggests that the free electrons respond to light in the infrared region.
The present inventors discovered that there is a specific range of the composition of tungsten and oxygen that is particularly effective as infrared absorbing fine particles. We came up with composite tungsten oxide particles.
Here, regarding infrared absorbing fine particles, using tungsten oxide fine particles and composite tungsten oxide fine particles as examples, (1) tungsten oxide fine particles, (2) composite tungsten oxide fine particles, (3) properties and characteristics of infrared absorbing fine particles, It will be explained in this order.

(1) Tungsten oxide fine particles Tungsten oxide fine particles are tungsten oxide fine particles expressed by the general formula WyOz (where W is tungsten, O is oxygen, and 2.2≦z/y≦2.999). .

In the tungsten oxide represented by the general formula WyOz, the composition range of tungsten and oxygen is such that the composition ratio of oxygen to tungsten is less than 3, and furthermore, when the infrared absorbing fine particles are written as WyOz, the composition range of tungsten and oxygen is 2. It is preferable that 2≦z/y≦2.999.
If the value of z/y is 2.2 or more, it is possible to avoid the appearance of a crystal phase of WO ₂ which is not the intended purpose in the tungsten oxide, and the chemical stability as a material is improved. can be obtained, making it an effective infrared absorbing fine particle. On the other hand, if the value of z/y is 2.999 or less, the required amount of free electrons will be generated, resulting in efficient infrared absorbing fine particles.

(2) Composite tungsten oxide fine particles Composite tungsten oxide is obtained by adding element M, which will be described later, to the above-described composite tungsten oxide (WO ₃ ). By controlling the amount of oxygen and adding element M that generates free electrons to the WO ₃ , more efficient infrared absorbing fine particles can be obtained. By adopting this configuration, free electrons are generated in the composite tungsten oxide, and strong absorption characteristics derived from free electrons are expressed particularly in the near-infrared region, making it effective as a near-infrared absorbing fine particle at a wavelength of around 1000 nm.
When the general formula of infrared absorbing fine particles that combines this control of the amount of oxygen and the addition of the element M that generates free electrons is written as MxWyOz (where M is the element M, W is tungsten, and O is oxygen). , 0.001≦x/y≦1, and 2.0≦z/y≦3.

Here, the element M in the composite tungsten oxide is H, He, alkali metal, alkaline earth metal, 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, Preferably, it is one or more selected from Mo, Ta, Re, Be, Hf, Os, Bi, I, and Yb.

Furthermore, from the viewpoint of stability in the MxWyOz to which element M is added, element M may include 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, More preferably, it is one or more elements selected from Nb, V, Mo, Ta, and Re. From the viewpoint of improving the optical properties and moist heat resistance as infrared absorbing fine particles, it is further preferred that element M belongs to an alkali metal, an alkaline earth metal element, a transition metal element, a group 4B element, or a group 5B element. preferable.

Regarding the value of x/y indicating the amount of addition of element M, if the value of x/y is greater than 0.001, a sufficient amount of free electrons will be generated in the composite tungsten oxide to obtain the desired infrared absorption characteristics. I can do it. As the amount of element M added increases, the amount of free electrons supplied increases and the infrared absorption efficiency also increases, but this effect is saturated when the value of x/y is about 1. Furthermore, it is preferable that the value of x/y be smaller than 1, since it is possible to avoid generation of an impurity phase in the infrared absorbing fine particles.

Regarding the value of z/y, which indicates the control of the amount of oxygen, in addition to the fact that the same mechanism works in the composite tungsten oxide expressed as MxWyOz as in the tungsten oxide expressed as WyOz mentioned above, the value of z/y Even when y=3.0 or 2.0≦z/y≦2.2, free electrons are supplied depending on the amount of element M added above. Therefore, 2.0≦z/y≦3.0 is preferable, more preferably 2.2≦z/y≦3.0, still more preferably 2.45≦z/y≦3.0.

Furthermore, when the composite tungsten oxide fine particles have a hexagonal crystal structure, the fine particles have improved transmission in the visible light region and improved absorption in the infrared region. This will be explained with reference to FIG. 1, which is a schematic plan view of this hexagonal crystal structure.
In FIG. 1, six octahedrons formed by WO ₆ units, indicated by reference numeral 11, are assembled to form a hexagonal void, and an element M indicated by reference numeral 12 is arranged in the void, forming one element. It constitutes a unit, and a large number of this one unit aggregate to form a hexagonal crystal structure.
In order to obtain the effect of improving light transmission in the visible light region and improving light absorption in the infrared region, the unit structure explained using FIG. 1 is included in the composite tungsten oxide fine particles. The composite tungsten oxide fine particles may be crystalline or amorphous.

When the composite tungsten oxide fine particles having a hexagonal crystal structure have a uniform crystal structure, the amount of element M added is preferably 0.2 or more and 0.5 or less in terms of x/y, more preferably 0. It is 33. Since the value of x/y is 0.33, it is considered that the above-mentioned element M is arranged in all the hexagonal voids.
When cations of element M are added and present in the hexagonal voids, the transmission of light in the visible light region is improved, and the absorption of light in the infrared region is improved. Generally, when an element M having a large ionic radius is added, the hexagonal crystal is likely to be formed. Specifically, one or more elements selected from Cs, K, Rb, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn, more preferably Cs, K, Rb, Tl, and In. When one or more elements selected from , Ba are added, hexagonal crystals are likely to be formed. Typical examples are Cs _0.33 WO _z , Cs _0.03 Rb _0.30 WO _z , Rb _0.33 WO _z , K _0.33 WO _z , Ba _0.33 WO _z (2.0≦z ≦3.0) and the like can be preferably mentioned. Of course, elements other than these may be used as long as the above-mentioned element M is present in the hexagonal void formed by WO ₆ units, and the element is not limited to the above-mentioned elements.

When the composite tungsten oxide fine particles having a hexagonal crystal structure have a uniform crystal structure, the amount of element M added is preferably 0.2 or more and 0.5 or less in terms of x/y, more preferably 0. It is 33. Since the value of x/y is 0.33, it is considered that the above-mentioned element M is arranged in all the hexagonal voids.

Further, composite tungsten oxides other than hexagonal crystals, such as tetragonal crystals and cubic crystals, are also effective as infrared absorbing fine particles. The absorption position in the infrared region tends to change depending on the crystal structure, and the absorption position tends to move toward longer wavelengths in the order of cubic < tetragonal < hexagonal. In addition, the hexagonal crystal, tetragonal crystal, and cubic crystal have a correspondingly low absorption in the visible light region, in that order. Therefore, it is preferable to use hexagonal composite tungsten oxide for applications that transmit more light in the visible region and absorb more light in the infrared region. However, the trends in the optical properties described here are just general trends and vary depending on the type of additive element, the amount added, and the amount of oxygen, and the present invention is not limited thereto.

(3) Properties and characteristics of infrared absorbing fine particles The infrared absorbing fine particles preferably contain the above-mentioned tungsten oxide fine particles and/or composite tungsten oxide fine particles. In this case, the infrared-absorbing fine particles according to the present invention largely absorb light in the near-infrared region, particularly in the vicinity of a wavelength of 1000 nm, so that the transmitted color tone thereof often ranges from blue to green.

From the viewpoint of exhibiting excellent infrared absorption characteristics, 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. To measure the crystallite diameter, measurement of an X-ray diffraction pattern by powder X-ray diffraction method (θ-2θ method) and analysis by Rietveld method are used. The X-ray diffraction pattern can be measured using, for example, a powder X-ray diffractometer "X'Pert-PRO/MPD" manufactured by PANalytical, Inc., Spectris Co., Ltd.

On the other hand, the dispersed particle size of the infrared absorbing fine particles can be selected depending on the intended use. The dispersed particle size is a concept that includes the particle size of aggregates, unlike the crystallite size of infrared absorbing fine particles.
When infrared absorbing fine particles are used for applications where transparency is desired to be maintained, it is preferable that the fine particles have a dispersed particle diameter of 800 nm or less. This is because particles with a dispersed particle size smaller than 800 nm do not completely block light due to scattering, maintain visibility in the visible light range, and at the same time efficiently maintain transparency. . Particularly when emphasis is placed on transparency in the visible light region, it is preferable to further consider scattering by particles.

When placing importance on reducing scattering caused by these particles, the dispersed particle diameter is preferably 200 nm or less, preferably 100 nm or less. The reason for this is that if the dispersed particle size of the particles is small, the scattering of light in the visible light range of wavelengths from 400 nm to 780 nm due to geometric scattering or Mie scattering is reduced, and as a result, the infrared absorbing film becomes like frosted glass. It is possible to avoid not being able to obtain clear transparency. That is, when the dispersed particle diameter becomes 200 nm or less, the above-mentioned geometric scattering or Mie scattering decreases and becomes a Rayleigh scattering region. This is because in the Rayleigh scattering region, scattered light is proportional to the sixth power of the particle diameter, so as the dispersed particle diameter decreases, scattering decreases and transparency improves.
Further, it is preferable that the dispersed particle diameter is 100 nm or less, since the amount of scattered light will be very small. From the viewpoint of avoiding light scattering, it is preferable that the dispersed particle size is small, and if the dispersed particle size is 1 nm or more, industrial production is easy.

By setting the dispersed particle size to 800 nm or less, the haze value of the infrared absorbing fine particle dispersion in which the infrared absorbing fine particles are dispersed in a medium can be 30% or less with a visible light transmittance of 85% or less. If the haze is greater than 30%, it will look like frosted glass and clear transparency will not be obtained.
The dispersed particle diameter of the infrared absorbing fine particles can be measured using an ELS-8000 manufactured by Otsuka Electronics Co., Ltd., which is based on the dynamic light scattering method.
Further, the dispersed particle size of the infrared absorbing fine particles is different from the dispersed particle size of the surface-treated infrared absorbing fine particles according to the present invention. Specifically, the dispersed particle size of the infrared absorbing fine particles was measured before surface treatment (surface coating), and the dispersed particle size of the surface-treated infrared absorbing fine particles was measured after the surface treatment. .

In addition, in tungsten oxide fine particles and composite tungsten oxide fine particles, the so-called "Magneli phase", which has a composition ratio expressed as 2.45≦z/y≦2.999, is chemically stable and has a composition ratio of 2.45≦z/y≦2.999. Since they have good absorption properties, they are preferred as infrared absorbing fine particles.

[2] Surface treatment agent for infrared absorbing fine particles Surface treatment agents used for surface coating of infrared absorbing fine particles include hydrolysis products of metal chelate compounds, polymers of hydrolysis products of metal chelate compounds, and hydrolysis of metal cyclic oligomer compounds. It is one or more selected from decomposition products and polymers of hydrolysis products of metal cyclic oligomer compounds.
The metal chelate compound and metal cyclic oligomer compound are preferably one or more selected from ether bonds, ester bonds, alkoxy groups, and acetyl groups, from the viewpoint that they are preferably metal alkoxides, metal acetylacetonates, and metal carboxylates. It is preferable to have.
Here, regarding the surface treatment agent, (1) metal chelate compounds, (2) metal cyclic oligomer compounds, (3) hydrolysis products of metal chelate compounds and metal cyclic oligomer compounds, and polymers thereof, (4) The amount of addition of the surface treatment agent will be explained in this order.

(1) Metal chelate compound The metal chelate compound used in the present invention is preferably one or more selected from Al-based, Zr-based, Ti-based, Si-based, and Ti-based chelate compounds containing an alkoxy group.

Examples of aluminum-based chelate compounds include aluminum alcoholates such as aluminum ethylate, aluminum isopropylate, aluminum sec-butyrate, and mono-sec-butoxyaluminum diisopropylate, or polymers thereof, ethyl acetoacetate aluminum diisopropylate, and aluminum tris. (ethylacetoacetate), octylacetoacetate aluminum diisoproplate, stearyl acetoaluminum diisopropylate, aluminum monoacetylacetonate bis(ethylacetoacetate), aluminum tris(acetylacetonate), and the like.
These compounds are produced by dissolving aluminum alcoholate in an aprotic solvent, petroleum solvent, hydrocarbon solvent, ester solvent, ketone solvent, ether solvent, amide solvent, etc., and adding β- This is an alkoxy group-containing aluminum chelate compound obtained by adding diketone, β-ketoester, monohydric or polyhydric alcohol, fatty acid, etc., heating under reflux, and performing a ligand substitution reaction.

Examples of zirconium-based chelate compounds include zirconium alcoholates such as zirconium ethylate and zirconium butyrate, or polymers thereof, zirconium tributoxystearate, zirconium tetraacetylacetonate, zirconium tributoxyacetylacetonate, zirconium dibutoxybis(acetyl acetonate), zirconium tributoxyethylacetoacetate, zirconium butoxyacetylacetonate bis(ethylacetoacetate), and the like.

Examples of titanium-based chelate compounds include titanium alcoholates and polymers thereof such as methyl titanate, ethyl titanate, isopropyl titanate, butyl titanate, and 2-ethylhexyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate, and titanium octylene glycolate. , titanium ethyl acetoacetate, titanium lactate, titanium triethanolaminate, and the like.

Examples of silicon-based chelate compounds include tetrafunctional silane compounds 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 partially hydrated thereof. Decomposition products can be used. Specific examples of the tetrafunctional silane compound include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane. Furthermore, the application of silane monomers (or oligomers) in which part or all of the alkoxy groups of these alkoxysilane monomers are hydrolyzed to become silanol (Si-OH) groups, and polymers that are self-condensed through a hydrolysis reaction. is also possible.

In addition, as a partial hydrolysis product of a tetrafunctional silane compound (there is no appropriate terminology that indicates the entire intermediate of a tetrafunctional silane compound), a part or all of the alkoxy group is hydrolyzed, Examples include silane monomers with silanol (Si-OH) groups, oligomers of tetramers and pentamers, and polymers (silicone resins) with a weight average molecular weight (Mw) of about 800 to 8,000. Note that not all of the alkoxysilyl groups (Si-OR) in the alkoxysilane monomer are hydrolyzed into silanol (Si-OH) during the hydrolysis reaction process.

Examples of zinc-based chelate compounds include zinc salts of organic carboxylic acids such as zinc octylate, zinc laurate, and zinc stearate, zinc acetylacetone chelate, zinc benzoylacetone chelate, zinc dibenzoylmethane chelate, and zinc ethyl acetoacetate chelate. I can give an example.

(2) Metal cyclic oligomer compound The metal cyclic oligomer compound is preferably one or more selected from Al-based, Zr-based, Ti-based, Si-based, and Zn-based cyclic oligomer compounds. Among these, cyclic aluminum oligomer compounds such as cyclic aluminum oxide octylate can be preferably exemplified.

(3) Hydrolysis products of metal chelate compounds and metal cyclic oligomer compounds, and polymers thereof In the present invention, some of the alkoxy groups, ether bonds, and ester bonds in the metal chelate compounds and metal cyclic oligomer compounds mentioned above are Alternatively, the surface of the infrared absorbing fine particles is coated with a hydrolysis product whose entire amount is hydrolyzed to become a hydroxyl group or a carboxyl group, and/or a polymer that is self-condensed through the hydrolysis reaction to form a coating film. , surface-treated infrared absorbing fine particles according to the present invention are obtained.

However, for example, in a reaction system where an organic solvent such as alcohol is present, even if sufficient water is present in the system due to the stoichiometric composition, the type and concentration of the organic solvent may vary. Therefore, not all of the alkoxy groups, ether bonds, and ester bonds of the metal chelate compound or metal cyclic oligomer compound that are the starting materials are hydrolyzed. Therefore, depending on the conditions of the surface treatment method described below, even after hydrolysis, the material may become an amorphous state in which carbon C is incorporated into the molecules of the hydrolyzable organism.
As a result, the coating film may contain undecomposed metal chelate compounds and/or metal cyclic oligomer compounds.

That is, the coating film that covers the surface of the infrared absorbing fine particles is formed by hydrolyzing some or all of the alkoxy groups, ether bonds, and ester bonds in the metal chelate compounds and metal cyclic oligomer compounds mentioned above, and forming hydroxyl groups and carboxyl groups. It is preferable that the resulting hydrolysis product is a polymer that is self-condensed through the hydrolysis reaction.

(4) Addition amount of surface treatment agent The addition amount of the above-mentioned metal chelate compound and metal cyclic oligomer compound is 0.05 parts by weight or more and 1000 parts by weight or less in terms of metal element, based on 100 parts by weight of the infrared absorbing fine particles. It is preferable that there be. The content is more preferably 5 parts by weight or more and 500 parts by weight or less, and most preferably 50 parts by weight or more and 250 parts by weight or less.

This is due to the effect that if the metal chelate compound or metal cyclic oligomer compound is 0.05 parts by weight or more, the hydrolysis products of those compounds or the polymers of the hydrolysis products coat the surface of the infrared absorbing fine particles. This is because the effect of improving heat and humidity resistance is achieved.
Further, if the amount of the metal chelate compound or the metal cyclic oligomer compound is 1000 parts by weight or less, it is possible to avoid an excessive amount of adsorption onto the infrared absorbing fine particles. In addition, the effect of improving heat and humidity resistance due to surface coating does not become saturated, and an improvement in the coating effect can be expected.
Furthermore, if the metal chelate compound or metal cyclic oligomer compound is 1000 parts by weight or less, the amount of adsorption to the infrared absorbing fine particles becomes excessive, and when the medium is removed, hydrolysis products of the metal chelate compound or metal cyclic oligomer compound, This is because it is possible to avoid easy granulation of fine particles together via the polymerized product of the hydrolysis product. Good transparency can be ensured by avoiding undesired granulation between the fine particles.
In addition, an increase in production costs due to an increase in the amount added and processing time due to an excess of the metal chelate compound or metal cyclic oligomer compound can also be avoided. Therefore, from an industrial standpoint, the amount of the metal chelate compound or metal cyclic oligomer compound added is preferably 1000 parts by weight or less.

[3] Surface treatment method for infrared absorbing fine particles There are several methods for surface treatment (surface coating method) for infrared absorbing fine particles. (A) Adding a surface treatment agent to an aqueous dispersion for forming a coating film. Two methods will be described: (B) a treatment method in which a surface treatment agent and water are added to a water-soluble organic solvent dispersion.

(A) Treatment method of adding a surface treatment agent to an aqueous dispersion for forming a coating film In a treatment method of adding a surface treatment agent to an aqueous dispersion for forming a coating film, first, infrared absorbing fine particles are An aqueous dispersion of infrared absorbing fine particles for forming a coating film dispersed in certain water (sometimes referred to as "aqueous dispersion for forming a coating film" in the present invention) is prepared. Then, a surface treatment agent is added to the prepared aqueous dispersion for forming a coating film, and the mixture is mixed and stirred. Then, the surface of the infrared absorbing fine particles becomes a product of hydrolysis of a metal chelate compound, a polymer of a hydrolysis product of a metal chelate compound, a hydrolysis product of a metal cyclic oligomer compound, a hydrolysis product of a metal cyclic oligomer compound. It is coated with a coating film containing one or more selected from polymers.

Here, regarding the treatment method of adding a surface treatment agent to an aqueous dispersion for forming a coating film, (1) preparation of an aqueous dispersion for forming a coating film, (2) infrared rays using an aqueous dispersion for forming a coating film, The method for surface treatment of absorbent particles and (3) treatment after mixing and stirring in the aqueous dispersion for forming a coating film will be explained in this order.

(1) Preparation of aqueous dispersion for forming a coating film In order to coat the surface of infrared absorbing fine particles and produce surface-treated infrared absorbing fine particles, first, the infrared absorbing fine particles are dispersed in water and the concentration is adjusted to an appropriate range. In addition, an aqueous dispersion for forming a coating film having a pH within an appropriate range is prepared.
Then, while mixing and stirring the coating film-forming aqueous dispersion having the concentration and pH, a surface treatment agent (see section "[2] Surface treatment agent for infrared absorbing fine particles") is added thereto. Then, while the dispersibility of the infrared absorbing fine particles is maintained due to the electrostatic repulsion between the fine particles, the surface of the fine particles becomes a product of hydrolysis products of metal chelate compounds, polymers of hydrolysis products of metal chelate compounds, metals, etc. It is coated with a coating film containing one or more selected from a hydrolysis product of a cyclic oligomer compound and a polymer of a hydrolysis product of a metal cyclic oligomer compound.

In preparing an aqueous dispersion for forming a coating film with a specific concentration and pH, infrared absorbing fine particles, such as tungsten oxide and/or composite tungsten oxide, are finely ground in advance and dispersed in water to form a monodisperse state. It is preferable to keep it.

At this time, the concentration range of the tungsten oxide and/or composite tungsten oxide to be dispersed is preferably 0.01% by mass or more and 80% by mass or less. Within this concentration range, the liquid stability of the dispersion is excellent. Furthermore, if an appropriate liquid medium, dispersant, coupling agent, and surfactant are selected, gelation of the dispersion and precipitation of particles will not occur for more than 6 months even when placed in a constant temperature bath at a temperature of 40°C. First, the dispersed particle size can be maintained within the range of 1 to 800 nm.

More preferably, the concentration range is 3% by mass or more and 80% by mass or less. This allows the pH of the aqueous dispersion for coating film formation to be 8 or less, and when a surface treatment agent is added later, the dispersibility of the infrared absorbing fine particles is maintained due to the electrostatic repulsion between the fine particles. Because it will be. However, even if the concentration range is 0.01% by mass or more and less than 3% by mass, the solvent replacement treatment described in "[5] Surface-treated infrared-absorbing fine particle dispersion (ii) Other manufacturing methods" By performing the drying treatment, it is possible to obtain a surface-treated infrared absorbing fine particle dispersion liquid with good dispersibility.
During this pulverization and dispersion treatment process, it is important to maintain a dispersed state and to prevent the fine particles from agglomerating each other. This is because during the next process of surface treatment of the infrared absorbing fine particles, the infrared absorbing fine particles aggregate and are coated on the surface in the form of aggregates, and as a result, the aggregates also form in the infrared absorbing fine particle dispersion described below. This is to avoid a situation in which the transparency of the infrared absorbing fine particle dispersion and the infrared absorbing base material, which will be described later, is reduced due to the presence of residual particles.

Specific methods for the pulverization and dispersion treatment include, for example, pulverization and dispersion treatment methods using devices such as bead mills, ball mills, sand mills, paint shakers, and ultrasonic homogenizers. Among them, pulverization and dispersion treatment using media such as beads, balls, and ottawa sand with agitation mills such as bead mills, ball mills, sand mills, and paint shakers is necessary to reach the desired dispersed particle size. This is preferable because it takes a short time.

The pH range of the aqueous dispersion for coating film formation is preferably 8 or less. This is because the dispersibility of the infrared absorbing fine particles is maintained by the electrostatic repulsion between the surface-treated infrared absorbing fine particles.

Here, when a surface treatment agent is added to the aqueous dispersion for forming a coating film, the pH of the aqueous dispersion for forming a coating film swings slightly toward the alkaline side. As a result, if the pH of the aqueous dispersion for forming a coating film exceeds 8, the surface-treated infrared absorbing fine particles will aggregate, and dispersion stability will not be ensured. On the other hand, since tungsten oxide and/or composite tungsten oxide are slightly dissolved in water, the pH of the aqueous dispersion for forming a coating film before addition of the surface treatment agent is shifted to the acid side. In addition, it is particularly easy to dissolve in an alkaline solution, and the more it dissolves, the more acidic the pH becomes. Because of this effect, as long as the tungsten oxide and/or composite tungsten oxide is dissolved, the pH can be maintained at 8 or lower even if a surface treatment agent is added. As a result, if the concentration range of tungsten oxide and/or composite tungsten oxide before addition of the surface treatment agent is 3% by mass or more, the amount of tungsten oxide that can be dissolved increases, so even after the addition of the surface treatment agent, the pH is 8 or less. is maintained. The dispersibility of the infrared absorbing fine particles is maintained by the electrostatic repulsion between the fine particles.
On the other hand, if the concentration range of tungsten oxide or/and composite tungsten oxide before adding the surface treatment agent is 80% by mass or less, aggregation due to interparticle interaction will not occur, and infrared absorbing fine particles will be dispersed due to electrostatic repulsion. Maintains sexuality.
For the above reasons, the concentration range of tungsten oxide and/or composite tungsten oxide before addition of the surface treatment agent is preferably 3% by mass or more and 80% by mass or less.

(2) Method for surface treatment of infrared absorbing fine particles using an aqueous dispersion for forming a coating film The present inventors added a surface treatment agent to the aqueous dispersion for forming a coating film while stirring and mixing the aqueous dispersion for forming a coating film, and It has been found that it is preferable to immediately complete the hydrolysis reaction of the added metal chelate compound or metal cyclic oligomer compound.
In addition, from the viewpoint of uniformly covering the surface of the infrared absorbing fine particles, it is preferable to add the surface treatment agent dropwise.
This is considered to be influenced by the reaction order of the added surface treatment agent. That is, in the aqueous dispersion for forming a coating film, the hydrolysis reaction of the surface treatment agent always takes place first, followed by the polymerization reaction of the generated hydrolysis product. As a result, the amount of carbon C remaining in the surface treatment agent molecules present in the coating film can be reduced compared to when using an aqueous dispersion for coating film formation that does not use water as a medium. it is conceivable that. We believe that by reducing the residual amount of carbon C in the surface treatment agent molecules present in the coating film, we were able to form a coating film that densely covers the surface of each infrared absorbing fine particle. .

When adding the surface treatment agent while mixing and stirring the prepared aqueous dispersion for forming a coating film, the aqueous dispersion for forming a coating film is mixed with water or an appropriate amount containing water in order to uniformly coat the infrared absorbing fine particles. It is also desirable to dilute it to an appropriate concentration with an organic solvent. If the dispersion concentration of tungsten oxide or/and composite tungsten oxide, which is infrared absorbing fine particles, is diluted to 3% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 20% by mass or less, infrared absorbing fine particles This is because all the surfaces are uniformly coated, the pH of the dispersion liquid can be set to 8 or less, and the dispersibility of the infrared absorbing fine particles is maintained due to the electrostatic repulsion between the fine particles.

When adding this surface treatment agent dropwise, in order to uniformly cover the infrared absorbing fine particles, the surface treatment agent itself is diluted with an appropriate solvent and added dropwise to adjust the amount of the surface treatment agent added per hour. It is also preferable to do so. The solvent used for dilution is preferably one that does not react with the surface treatment agent and is highly compatible with water, which is the medium of the aqueous dispersion for forming a coating film. Specifically, alcohol-based, ketone-based, glycol-based solvents, and the like can be preferably used.

The dilution ratio of the surface treatment agent is not particularly limited. However, from the viewpoint of ensuring productivity, the dilution ratio is preferably 100 times or less.

In addition, in the above-mentioned aqueous dispersion for forming a coating film, the metal chelate compound, the metal cyclic oligomer compound, their hydrolysis products, and the polymers of the hydrolysis products are decomposed into metal ions immediately after addition. However, when the solution becomes a saturated aqueous solution, the decomposition of the metal ions ends. That is, after the decomposition of metal ions is completed, the added surface treatment agent becomes a hydrolyzed product or a polymer thereof, forming a coating film that covers the surface of the infrared absorbing fine particles.
On the other hand, in the aqueous dispersion for forming a coating film using water as a medium, the infrared absorbing fine particles maintain their dispersion due to electrostatic repulsion.
As a result, the surfaces of all infrared absorbing fine particles are formed by hydrolysis products of metal chelate compounds, polymers of hydrolysis products of metal chelate compounds, hydrolysis products of metal cyclic oligomer compounds, and hydrolysis products of metal cyclic oligomer compounds. It is considered that the surface-treated infrared absorbing fine particles according to the present invention are produced by being coated with a coating film containing one or more types selected from polymerized products.

(3) Treatment after mixing and stirring in the aqueous dispersion for forming a coating film The surface-treated infrared absorbing fine particles according to the present invention obtained by the above-mentioned surface treatment method can be used as a raw material for an infrared absorbing fine particle dispersion or an infrared absorbing base material. It can be used in the form of fine particles or dispersed in a liquid or solid medium.
Here, the generated surface-treated infrared absorbing fine particles do not require further heat treatment to increase the density and chemical stability of the coating film. This is because the density and adhesion of the coating film are sufficiently high that the desired heat and humidity resistance can already be obtained without the heat treatment.

(B) A treatment method in which a surface treatment agent and water are added to a water-soluble organic solvent dispersion In a treatment method in which a surface treatment agent and water are added to a water-soluble organic solvent dispersion, first, the water-soluble A dispersion liquid is prepared by dispersing infrared absorbing fine particles in an organic solvent. Then, a surface treatment agent and water are added in parallel to the prepared dispersion while mixing and stirring is performed. As a result, the surface of the infrared absorbing fine particles is formed by a hydrolysis product of a metal chelate compound, a polymer of a hydrolysis product of a metal chelate compound, a hydrolysis product of a metal cyclic oligomer compound, a hydrolysis product of a metal cyclic oligomer compound. It is coated with a coating film containing one or more selected from the following.

In this treatment method, the respective addition speeds of the surface treatment agent and water, which are added in parallel, are important. As mentioned above, it is desirable that the surface treatment agent undergoes a hydrolysis reaction immediately after addition, so when the surface treatment agent is added, sufficient water must be added to complete the hydrolysis reaction. On the other hand, if too much water is added first, some infrared absorbing fine particles may agglomerate or the infrared absorbing properties may deteriorate. For example, when the infrared absorbing fine particles are cubic sodium tungsten bronze, it reacts with water, resulting in a decrease in infrared absorbing properties. Therefore, it is important to add a small amount of water to an extent that does not adversely affect the infrared absorbing fine particles, and to allow the added water to react with the surface treatment agent and be consumed in sequence. Since it is important to adjust the rate of addition of the surface treatment agent and water, it is preferable to add both of them dropwise, that is, to add them in parallel.
However, if excessive addition of water does not adversely affect the infrared absorbing fine particles, water may be added first and the surface treatment agent may be added later.

Above, (A) a treatment method of adding a surface treatment agent to an aqueous dispersion for forming a coating film, and (B) a treatment method of adding a surface treatment agent and water to a water-soluble organic solvent dispersion. As described above with reference to the method, the surface-treated infrared absorbing fine particles according to the present invention do not require heat treatment after mixing and stirring, and therefore do not cause agglomeration, and therefore require no dispersion treatment to break up the agglomeration. is not necessary or takes only a short time. As a result, the coating film of the surface-treated infrared absorbing fine particles according to the present invention uniformly and firmly covers the individual infrared absorbing fine particles without damaging them. Infrared absorbing fine particle dispersions and infrared absorbing substrates produced using the surface-treated infrared absorbing fine particles are considered to exhibit superior moist heat resistance than those obtained by conventional methods.

[4] Dispersion Solvent The dispersion solvent of the surface-treated infrared absorbing fine particle dispersion according to the present invention is a solvent containing water, and furthermore, a solvent consisting essentially of water.
That is, when the dispersion solvent contains a trace amount of organic solvent resulting from the manufacturing process of the surface-treated infrared absorbing fine particle dispersion according to the present invention, and when it contains one or more types of water-soluble organic substances as desired. There is. The organic solvents and water-soluble organic substances include alcohols, glycols, water-soluble resins, etc., but they are preferably ones with low toxicity to the human body.

[5] Surface-treated infrared-absorbing fine particle dispersion The surface-treated infrared-absorbing fine particle dispersion according to the present invention is one in which the surface-treated infrared-absorbing fine particles according to the present invention are dispersed in water, which is a dispersion solvent.
The surface-treated infrared-absorbing fine particle dispersion according to the present invention will be described in the following order: (1) surface-treated infrared-absorbing fine particle dispersion; and (2) method for producing the surface-treated infrared-absorbing fine particle dispersion.

(1) Surface-treated infrared-absorbing fine particle dispersion The pH value of the surface-treated infrared-absorbing fine particle dispersion according to the present invention is preferably 4 or more and 10 or less. Further, it is preferable that the concentration of the surface-treated infrared absorbing fine particles is 0.01% by mass or more and 80% by mass or less. If the concentration is within this range, the surface-treated infrared absorbing fine particles can maintain dispersibility in water.

The surface-treated infrared-absorbing fine particle dispersion according to the present invention may further contain a dispersant in order to improve the dispersibility of the surface-treated infrared-absorbing fine particles and to avoid coarsening of the dispersed particle size due to reaggregation. Additionally, additives can be used when adjusting the pH.

When adding a dispersant or an additive to the surface-treated infrared absorbing fine particle dispersion according to the present invention, a water-soluble dispersant is preferable. Furthermore, those having an acidic functional group and having an acid value of 10 mg/KOH or more are preferable. An ammonium salt or an acrylic polymer dispersant can be preferably used.
Preferred specific examples of commercially available dispersants include SOLSPERSE (registered trademark) manufactured by Lubrizol (hereinafter the same) 20000, 27000, 40000, 41000, 41090, 43000, 44000, 46000, 47000, 53095, 54000, 64000, 65000, 66000 etc.; DISPERBYK (registered trademark) manufactured by BYK Chemie Japan (same below) -102, 180, 184, 185, 187, 190, 191, 192, 193, 194N, 2010, 2012, 2015, 2060, 2096, Anti- Terra (registered trademark)-250, etc.; JONCRYL (registered trademark) (hereinafter the same) 67, 678, 586, 611, 682, 683, 690, etc. manufactured by BASF Japan;

Furthermore, in order to improve dispersion stability, two or more types of dispersants can be used in combination. For example, when two types of dispersants are used, one type is a dispersant that has an acidic functional group, and the other type is a nonionic dispersant that does not have acidic or basic functional groups. , may exhibit excellent dispersion stability. Of course, even when a dispersant having all acidic functional groups is used as a dispersant, excellent dispersion stability may be exhibited in some cases.

(2) Method for producing surface-treated infrared-absorbing fine particle dispersion The surface-treated infrared-absorbing fine particle dispersion according to the present invention is obtained by dispersing the surface-treated infrared-absorbing fine particles according to the present invention in water, which is a dispersion solvent. However, the surface-treated infrared-absorbing fine particle dispersion obtained immediately after the surface treatment of the infrared-absorbing fine particles may contain organic solvents such as alcohol produced by the hydrolysis reaction of the surface treatment agent, or the surface treatment Depending on the type of agent, it may contain an organic solvent having a boiling point higher than water.

Depending on the use of the surface-treated infrared absorbing fine particle dispersion according to the present invention, it may be preferable to reduce the content of the organic solvent as much as possible. Therefore, in such a case, the content of the organic solvent can be reduced by appropriate methods such as solvent replacement treatment, washing treatment, drying treatment, etc.

Hereinafter, the method for producing a dispersion of surface-treated infrared-absorbing fine particles will be described. (i) A method of producing a dispersion of surface-treated infrared-absorbing fine particles directly after the surface treatment of the surface-treated infrared-absorbing fine particles according to the present invention. and (ii) other manufacturing method, which includes a step of removing an organic solvent after the surface treatment of the surface-treated infrared absorbing fine particles according to the present invention.

(i) Manufacturing method for directly forming a dispersion The surface-treated infrared-absorbing fine particle dispersion according to the present invention is produced by the method described in [3] Surface treatment method for infrared-absorbing fine particles (A) Surface treatment for forming an aqueous dispersion for forming a coating film. When the method described in the section ``(2) Surface treatment method of infrared absorbing fine particles using an aqueous dispersion for coating film formation'' is adopted, a dispersion containing surface treated infrared absorbing fine particles and water is used. Therefore, this can be used as it is as a surface-treated infrared absorbing fine particle dispersion according to the present invention. At this time, in order to reduce the content of organic solvent, it is desirable that the amount of organic components derived from the surface treatment agent be as small as possible. Therefore, it is preferable to use a low-molecular-weight surface treatment agent without diluting it with an organic solvent. for example,
In this case, a dispersant or an additive may be added to the surface-treated infrared-absorbing fine particle dispersion as necessary to improve and stabilize the dispersibility of the surface-treated infrared-absorbing fine particles.

Specific methods for dispersing the surface-treated infrared absorbing fine particles include methods similar to the above-mentioned pulverization and dispersion treatment methods, such as using equipment such as bead mills, ball mills, sand mills, paint shakers, and ultrasonic homogenizers. The methods used are listed below.
During the dispersion treatment, it is preferable to consider redispersion conditions so that the coating film on the surface of the surface-treated infrared absorbing fine particles is not damaged or peeled off. For example, it is preferable that the time required for distributed processing be extremely short.

(ii) Other manufacturing methods As mentioned above, the surface-treated infrared-absorbing fine particle dispersion according to the present invention contains an organic solvent in the dispersion immediately after the surface treatment of the infrared-absorbing fine particles according to the present invention, depending on the manufacturing method. Sometimes.
For example, if the method described in the section "[3] Surface treatment method for infrared absorbing fine particles (B) treatment method of adding a surface treatment agent and water to a water-soluble organic solvent dispersion" is adopted, the surface treatment Examples include cases where aluminum ethyl acetoacetate diisopropylate is used as the agent.

In particular, when aluminum ethyl acetoacetate diisopropylate is used as the surface treatment agent, ethyl acetoacetate with a boiling point of 181° C. remains due to the hydrolysis reaction and is contained in the dispersion immediately after surface treatment. Since these solvents have a boiling point higher than the boiling point of water, it is extremely difficult to evaporate and remove only the solvent while leaving water by heat treatment.

In such a case, regarding the method for producing the surface-treated infrared-absorbing fine particle dispersion according to the present invention by removing the organic solvent from the dispersion of infrared-absorbing fine particles immediately after the surface treatment, <1> Surface-treated infrared absorbing by solvent replacement treatment A method for producing a fine particle dispersion, <2> a method for producing a surface-treated infrared-absorbing fine particle dispersion by washing treatment, and <3> a method for producing a surface-treated infrared-absorbing fine particle dispersion by drying treatment will be explained in this order.

<1> Method for producing a dispersion of surface-treated infrared-absorbing fine particles by solvent substitution treatment To produce the dispersion of surface-treated infrared-absorbing fine particles according to the present invention by solvent substitution treatment, first, the dispersion of surface-treated infrared-absorbing fine particles immediately after surface treatment is performed. Separate liquid into solid and liquid. In order to perform the solid-liquid separation, the dispersion concentration of the infrared absorbing fine particles in the aqueous dispersion for coating film formation before surface treatment must be less than 3% by mass, or the dispersion of the surface treated infrared absorbing fine particles immediately after the surface treatment must be carried out. A pH adjuster may be added to the liquid to adjust the pH value to 9 or higher.

Then, by repeating the removal of the supernatant by decantation using pure water from the solid-liquid separated dispersion and the solid-liquid separation operation (solvent replacement treatment) by adding pure water and a pH adjuster, organic Solvent content can be reduced. The more times the decantation and addition of pure water are performed, the more the content of the organic solvent can be reduced, but by repeating the process three or more times, the content can be reduced to a practical level.

<2> Method for producing a dispersion of surface-treated infrared-absorbing fine particles by solvent replacement treatment or cleaning treatment Solid-liquid separated dispersion as explained in the section "<1> Method for producing a dispersion of surface-treated infrared-absorbing fine particles by solvent replacement treatment" By filtering the liquid, a slurry of surface-treated infrared absorbing fine particles is extracted. The organic solvent content can also be reduced by repeating dehydration treatment using a filter press or the like and washing treatment by adding pure water to the extracted slurry. The more times the dehydration treatment and addition of pure water are performed, the more the content of the organic solvent can be reduced, but by repeating the dehydration treatment three times or more, the residual amount can be reduced to a practical level.

<3> Method for producing a dispersion of surface-treated infrared-absorbing fine particles by drying treatment Immediately after the surface treatment, the dispersion of surface-treated infrared-absorbing fine particles is subjected to drying treatment under conditions that do not cause strong aggregation of the surface-treated infrared-absorbing fine particles. Obtain infrared absorbing fine particle powder. Then, by adding the surface-treated infrared-absorbing fine particle powder to pure water and dispersing it by an appropriate method, a surface-treated infrared-absorbing fine particle dispersion according to the present invention can be obtained.

In the drying process, it may also be necessary to evaporate organic solvents that have a boiling point higher than water. In that case, the surface-treated infrared absorbing fine particle dispersion liquid will be dried at a temperature higher than the boiling point of water (100° C. at 1 atmosphere). In such a case, the atmosphere for the drying treatment is preferably a reduced pressure atmosphere from the viewpoint of being able to remove all the solvent at a lower temperature. Further, from the viewpoint of preventing oxidative deterioration of the infrared absorbing fine particles (for example, tungsten oxide and/or composite tungsten oxide), the atmosphere for the drying treatment is preferably a reduced pressure inert gas atmosphere or a vacuum atmosphere.

On the other hand, it is important to take care that the temperature of the drying treatment does not exceed the temperature at which the surface-treated infrared absorbing fine particles aggregate to form strong aggregates. This is because transparency is required in most cases in the infrared absorbing fine particle dispersion and infrared absorbing substrate produced using the surface-treated infrared absorbing fine particle dispersion according to the present invention.

Once the surface-treated infrared absorbing fine particles form a strong aggregate, redispersion thereof becomes extremely difficult. When an infrared absorbing fine particle dispersion or an infrared absorbing base material is produced using an aggregate of surface-treated infrared absorbing fine particles, a product with a high degree of haze may be obtained.

Therefore, in order to avoid this situation, the surface-treated infrared-absorbing fine particles should be dried at a temperature that does not exceed the temperature at which they form strong aggregates, and the obtained surface-treated infrared-absorbing fine particles should be decomposed in a dry and/or wet manner. After crushing, it is preferable to redisperse it in pure water. Specific methods for crushing and redispersing treatment include methods similar to the crushing and dispersing treatment methods described above, such as methods using equipment such as bead mills, ball mills, sand mills, paint shakers, and ultrasonic homogenizers. Can be mentioned. At this time, it is necessary to consider redispersion conditions so that the coating film on the surface of the surface-treated infrared absorbing fine particles is not damaged or peeled off. For example, it is desirable that the time required for crushing and redispersion treatment be extremely short.

(3) Method of using the surface-treated infrared-absorbing fine particle dispersion The surface-treated infrared-absorbing fine particle dispersion according to the present invention produced as described above is applied to the surface of an appropriate base material and cured to form an infrared absorbing fine particle dispersion. It can be used as a material. Furthermore, since the infrared absorbing fine particles have the function of absorbing infrared rays and converting them into heat, the formed cured film can also be used as a light-to-heat conversion layer. At this time, since the surface-treated infrared absorbing fine particle dispersion according to the present invention contains almost no organic solvent component, the coating treatment can be performed without harming the health of the workers in the process.

In addition, if the surface-treated infrared-absorbing fine particle dispersion contains a dispersant, it can be dried and pulverized to form a powdery surface-treated infrared-absorbing fine particle dispersion (in the present invention, "surface-treated infrared-absorbing fine particles"). It can also be used as a raw material added to infrared absorption products and photothermal conversion products. That is, a surface-treated infrared-absorbing fine particle dispersion powder in which the surface-treated infrared-absorbing fine particles according to the present invention is dispersed in a solid medium is obtained, and the surface-treated infrared-absorbing fine particle dispersion powder is redispersed into a liquid. It may be dispersed in a medium and used as a dispersion for infrared absorbing products, or it may be kneaded into a resin as described below. At this time, since the surface-treated infrared absorbing fine particle dispersion according to the present invention contains almost no organic solvent component, the drying process can be carried out without harming the health of the workers in the process. In addition, the surface-treated infrared absorbing fine particle dispersion powder obtained by the drying process contains almost no organic components as a residual solvent, so the crushing process, dispersion process, and resin kneading process can be performed without harming the health of process workers. I can do it.

(4) Dispersed particle size of surface-treated infrared-absorbing fine particles The surface-treated infrared-absorbing fine particles in the surface-treated infrared-absorbing fine particle dispersion according to the present invention produced as described above are known to be dispersed due to the method of use thereof. desirable. In terms of the dispersed particle diameter of the surface-treated infrared absorbing fine particles, it is desirable that the diameter is 20 nm or more and 400 nm or less.

(5) Moisture and heat resistance of surface-treated infrared-absorbing fine particle dispersion When the surface-treated infrared-absorbing fine particle dispersion according to the present invention is exposed, for example, to an air atmosphere of 85°C for 24 hours, the amount of change in solar transmittance before and after the exposure is Satisfy 4.0% or less. From this, it was found that the surface-treated infrared absorbing fine particle dispersion according to the present invention maintains excellent infrared absorbing properties even when exposed to high humidity and high heat environments.

The present invention will be specifically described below with reference to Examples. However, the present invention is not limited to the following examples.
The dispersed particle size of the fine particles in the dispersion liquid in Examples and Comparative Examples is shown as an average value measured by a particle size measuring device (ELS-8000 manufactured by Otsuka Electronics Co., Ltd.) based on a dynamic light scattering method. In addition, the crystallite diameter was measured by powder X-ray diffraction method (θ-2θ method) using a powder X-ray diffraction device (X'Pert-PRO/MPD manufactured by PANalytical, Spectris Co., Ltd.), and by Rietveld method. Calculated.

The optical properties of the surface-treated infrared absorbing fine particle dispersion were determined by diluting it with pure water so that the visible light transmittance was 80% in a measurement glass cell of a spectrophotometer. -4100) in the wavelength range of 200 nm to 2600 nm at intervals of 5 nm, and the visible light transmittance and solar transmittance were calculated according to JISR3106.

Furthermore, the method for evaluating the heat and humidity resistance of the surface-treated infrared-absorbing fine particle dispersion is to expose the surface-treated infrared-absorbing fine particle dispersion to an air atmosphere at 85° C. for 24 hours.
For example, when hexagonal cesium tungsten bronze particles are used as infrared absorbing particles, those with a change in solar transmittance of 4.0% or less before and after the exposure are judged to have good heat and humidity resistance; If it exceeds 4.0%, it is judged that the moisture and heat resistance is insufficient. When cubic sodium tungsten bronze particles are used, those with a change in solar transmittance of 6.0% or less before and after exposure are considered to have good moist heat resistance, and those with a change of more than 6.0% are considered to have good heat and humidity resistance. It was judged that the moisture and heat resistance was insufficient.

[Example 1]
Cs/W (molar ratio) = 0.33 hexagonal cesium tungsten bronze (Cs _0.33 WO _z , 2.2≦z≦3.0) powder (YM-01 manufactured by Sumitomo Metal Mining Co., Ltd.) 25% by mass The mixed solution obtained by mixing 75% by mass of pure water was loaded into a paint shaker containing 0.3 mmφ ZrO ₂ beads, and pulverized and dispersed for 10 hours to obtain Cs _0.33 WO _z according to Example 1. A dispersion of fine particles was obtained. The dispersed particle diameter of the Cs _0.33 WO _z fine particles in the obtained dispersion was measured and found to be 100 nm. In addition, as settings for particle size measurement, the particle refractive index was set to 1.81, and the particle shape was set to be non-spherical. Further, the background was measured using pure water, and the solvent refractive index was set to 1.33. After removing the solvent from the obtained dispersion, the crystallite diameter of the obtained Cs _0.33 WO _z fine particles was measured and found to be 32 nm.

The obtained dispersion of Cs _0.33 WO _z fine particles and pure water were mixed to prepare the aqueous dispersion A for coating film formation according to Example 1 in which the concentration of Cs _0.33 WO _z fine particles was 2% by mass. Obtained.
On the other hand, 2.5% by mass of aluminum ethyl acetoacetate diisopropylate as an aluminum-based chelate compound and 97.5% by mass of isopropyl alcohol (IPA) were mixed to obtain a surface treatment agent diluted liquid a.

890 g of the obtained aqueous dispersion A for forming a coating film was placed in a beaker, and 360 g of the surface treatment agent diluted liquid A was added dropwise thereto over 3 hours while stirring strongly with a stirrer equipped with blades. After the surface treatment agent dilution liquid a was added dropwise, stirring was further performed at a temperature of 20° C. for 24 hours to produce a ripening liquid according to Example 1. Next, a drying process was performed at a temperature of 120° C. for 24 hours using vacuum fluidized drying to evaporate the medium from the ripening solution to obtain the powder containing the surface-treated infrared-absorbing fine particles according to Example 1 (surface-treated infrared-absorbing fine particle powder). ) was obtained.

10% by mass of the surface-treated infrared absorbing fine particle powder according to Example 1 and 90% by mass of pure water were mixed. The obtained mixed solution was loaded into a paint shaker containing 0.3 mmφZrO ₂ beads and crushed for 1 hour to obtain a surface-treated infrared absorbing fine particle dispersion according to Example 1.

The dispersed particle diameter of the obtained surface-treated infrared absorbing fine particle dispersion according to Example 1 was measured and found to be 180 nm. In addition, as settings for particle size measurement, the particle refractive index was set to 1.81, and the particle shape was set to be non-spherical. Further, the background was measured using pure water, and the solvent refractive index was set to 1.33.

Further, when the optical properties of the surface-treated infrared absorbing fine particle dispersion according to Example 1 were measured, the visible light transmittance was 79.6% and the solar transmittance was 56.6%.

After exposing the obtained surface-treated infrared absorbing fine particle dispersion according to Example 1 to an air atmosphere at 85° C. for 24 hours, the optical properties were measured, and the visible light transmittance was 80.2% and the solar transmittance was 58. It was .5%.
It was also found that the amount of change in visible light transmittance before and after exposure to an atmospheric atmosphere at 85° C. was 0.6%, and the amount of change in solar radiation transmittance was 1.9%, both of which were small.

[Example 2, 3]
Surface-treated infrared absorbing fine particle dispersions according to Examples 2 and 3 were obtained by performing the same operations as in Example 1, except that the amount of surface treatment agent diluted liquid a and the dropwise addition time were changed. , the same evaluation as in Example 1 was performed. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Example 4]
The aging liquid according to Example 1 was allowed to stand for 1 hour to perform solid-liquid separation between the surface-treated infrared absorbing fine particles and the medium. Next, only the supernatant medium was removed by decantation using pure water to obtain an infrared absorbing fine particle slurry. Pure water was added to the resulting infrared absorbing fine particle slurry, and 0.5% by mass of cesium carbonate was added as a pH adjuster to the total, stirred for 1 hour, left to stand for 1 hour, and surface treated for infrared absorption again. Solid-liquid separation was performed between the fine particles and the medium.
This decantation and addition of pure water were repeated two more times (decantation and addition of pure water were performed three times in total) to obtain a surface-treated infrared absorbing fine particle dispersion according to Example 4.
The same evaluation as in Example 1 was performed on the surface-treated infrared absorbing fine particle dispersion according to Example 4. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Example 5]
Aqueous dispersion A for coating film formation according to Example 5, in which the dispersion of Cs _0.33 WO _z fine particles according to Example 1 and pure water are mixed, and the concentration of Cs _0.33 WO _z fine particles is 6% by mass. I got -6.
Put 890 g of the obtained aqueous dispersion A-6 for coating film formation into a beaker, and add aluminum ethyl acetoacetate diisopropylene, an aluminum-based chelate compound, as a surface treatment agent while stirring strongly with a stirrer equipped with blades. 133.5 g of chloride was added dropwise over 1 hour. After the surface treatment agent was added dropwise, stirring was further performed at a temperature of 20° C. for 24 hours to prepare a surface treated infrared absorbing fine particle dispersion according to Example 5.
Regarding the surface-treated infrared absorbing fine particle dispersion according to Example 5, the same evaluation as in Example 1 was performed. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Example 6]
A diluted surface treatment agent solution b according to Example 6 was obtained by mixing 2.4% by mass of zirconium tributoxyacetylacetonate and 97.6% by mass of isopropyl alcohol. A surface-treated infrared absorbing fine particle dispersion according to Example 6 was prepared in the same manner as in Example 1, except that diluted surface treatment agent b was used instead of diluted surface treatment agent a.
The same evaluation as in Example 1 was performed on the surface-treated infrared absorbing fine particle dispersion according to Example 6. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Example 7]
A diluted surface treatment agent liquid c according to Example 7 was obtained by mixing 2.6% by mass of diisopropoxytitanium bisethyl acetoacetate and 97.4% by mass of isopropyl alcohol. A surface-treated infrared absorbing fine particle dispersion according to Example 7 was prepared in the same manner as in Example 1, except that diluted surface treatment agent c was used instead of diluted surface treatment agent a.
The same evaluation as in Example 1 was performed on the surface-treated infrared absorbing fine particle dispersion according to Example 7. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Example 8]
25% by mass of cubic sodium tungsten bronze powder (manufactured by Sumitomo Metal Mining Co., Ltd.) with Na/W (molar ratio) = 0.33 and 75% by mass of isopropyl alcohol were mixed, and the resulting mixture was mixed into a 0.3mmφ ZrO The mixture was loaded into a paint shaker containing ₂ beads and subjected to pulverization and dispersion treatment for 10 hours to obtain a dispersion of Na _0.33 WO _z fine particles according to Example 8. The dispersed particle diameter of the Na _0.33 WO _z fine particles in the obtained dispersion was measured and found to be 100 nm. In addition, as settings for particle size measurement, the particle refractive index was set to 1.81, and the particle shape was set to be non-spherical. Further, the background was measured using isopropyl alcohol, and the solvent refractive index was set to 1.38. Further, after removing the solvent of the obtained dispersion, the crystallite diameter was measured and found to be 32 nm.

A dispersion of Na _0.33 WO _z fine particles according to Example 8 and isopropyl alcohol were mixed to prepare an aqueous dispersion B for forming a coating film in which the concentration of infrared absorbing fine particles (cubic sodium tungsten bronze fine particles) was 2%. Obtained. Put 520 g of the obtained aqueous dispersion B for coating film formation into a beaker, and while stirring strongly with a stirrer equipped with blades, 360 g of surface treatment agent diluted solution A and 100 g of pure water as diluent d were mixed in parallel over 3 hours. Added dropwise. After the dropwise addition, stirring was performed at a temperature of 20° C. for 24 hours to prepare a ripening liquid according to Example 8. Next, the medium was evaporated from this aged liquid by vacuum fluidized drying at a temperature of 120° C. for 24 hours to obtain a surface-treated infrared absorbing fine particle powder according to Example 8.

The surface according to Example 8 was prepared by performing the same operation as in Example 1, except that the surface treated infrared absorbing fine particle powder according to Example 8 was used instead of the surface treated infrared absorbing fine particle powder according to Example 1. A treated infrared absorbing fine particle dispersion was prepared.
The same evaluation as in Example 1 was performed on the surface-treated infrared absorbing fine particle dispersion according to Example 8. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Examples 9 to 11]
Instead of hexagonal cesium tungsten bronze powder, hexagonal potassium tungsten bronze powder with K/W (molar ratio) = 0.33 (Example 9) or hexagonal rubidium with Rb/W (molar ratio) = 0.33 Dispersed particle diameters of infrared absorbing fine particles according to Examples 9 to 11 were determined in the same manner as in Example 1 except that tungsten bronze powder (Example 10) and Magnelli phase W ₁₈ O ₄₉ (Example 11) were used. and the crystallite diameter was measured. Then, an aqueous dispersion for forming a coating film C according to Example 9, an aqueous dispersion for forming a coating film D according to Example 10, and an aqueous dispersion for forming a coating film E according to Example 11 were obtained.

The surface treatment infrared rays according to Examples 9 to 11 were obtained by performing the same operation as in Example 1, except that the aqueous dispersions C to E for forming a coating film were used instead of the aqueous dispersion liquid A for forming a coating film. An absorbent particle dispersion was prepared. Then, the same evaluation as in Example 1 was performed on the surface-treated infrared absorbing fine particle dispersions according to Examples 9 to 11. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Example 12, 13]
25% by mass of hexagonal cesium tungsten bronze (Cs _0.33 WO _z ) powder (YM-01 manufactured by Sumitomo Metal Mining Co., Ltd.) with Cs/W (molar ratio) = 0.33 and 75% by mass of pure water were mixed. The resulting mixed solution was loaded into a paint shaker containing 0.3 mmφ ZrO ₂ beads and subjected to pulverization and dispersion treatment for 4 hours (Example 12) or 6 hours (Example 13). A dispersion liquid of Cs _0.33 WO _z fine particles was obtained. When the dispersed particle diameter of the Cs _0.33 WO _z fine particles in the obtained dispersion was measured, it was 140 nm in Example 12 and 120 nm in Example 13. In addition, as settings for particle size measurement, the particle refractive index was set to 1.81, and the particle shape was set to be non-spherical. Further, the background was measured using pure water, and the solvent refractive index was set to 1.33.
After removing the solvent from the resulting dispersion, the crystallite diameter was measured, and found to be 42 nm in Example 12 and 50 nm in Example 13.

A coating according to Example 12 in which the obtained dispersion of Cs _0.33 WO _z particles according to Examples 12 and 13 was mixed with pure water, and the concentration of Cs _0.33 WO _z particles was 2% by mass. A film-forming aqueous dispersion F and a coating film-forming aqueous dispersion G according to Example 13 were obtained.
By performing the same operation as in Example 1, except that the aqueous dispersions F and G for forming a coating film were used instead of the aqueous dispersion liquid A for forming a coating film, and the dropping time of the surface treatment diluent was changed. Surface-treated infrared absorbing fine particle dispersions according to Examples 12 and 13 were prepared. Then, the same evaluation as in Example 1 was performed on the surface-treated infrared absorbing fine particle dispersions according to Examples 12 and 13. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Examples 14 to 18]
10% by mass of the surface-treated infrared absorbing fine particle powder according to Example 2, 85% by mass of pure water, and a dispersant α to ε (α in Example 14, β in Example 15, γ in Example 16, and γ in Example 17) (in Example 18, δ and ε in Example 18, respectively) were mixed with 5% by mass, and the resulting mixture was loaded into a paint shaker containing 0.3 mmφ ZrO ₂ beads and crushed for 1 hour. Aqueous dispersion for forming a coating film A-α according to Example 14, aqueous dispersion for forming a coating film A-β according to Example 15, aqueous dispersion for forming a coating film A-γ according to Example 16, Examples An aqueous dispersion A-δ for forming a coating film according to Example 17 and an aqueous dispersion A-ε for forming a coating film according to Example 18 were obtained.

Here, the dispersant α has a functional group of phosphoric acid, an acid value of 60 mgKOH/g, and a base value of 0 mgKOH/g.
The dispersant β has a carboxylic acid functional group, an acid value of 70 mgKOH/g, and a base value of 0 mgKOH/g.
The dispersant γ has a carboxylic acid functional group, an acid value of 15 mgKOH/g, and a base value of 0 mgKOH/g.
The dispersant δ has a carboxylic acid functional group, an acid value of 110 mgKOH/g, and a base value of 0 mgKOH/g.
The dispersant ε contains phosphoric acid as a functional group, and has an acid value of 85 mgKOH/g and a base value of 85 mgKOH/g.

Except that the aqueous dispersions A-α to A-ε for forming a coating film according to Examples 14 to 18 were used instead of the aqueous dispersion A for forming a coating film, and the dropping time of the surface treatment diluent was changed. By performing the same operations as in Example 1, surface-treated infrared absorbing fine particle dispersions according to Examples 14 to 18 were prepared. Then, the same evaluation as in Example 1 was performed on the surface-treated infrared absorbing fine particle dispersions according to Examples 14 to 18. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Example 19]
10% by mass of the surface-treated infrared absorbing fine particle powder according to Example 2, 80% by mass of pure water, 5% by mass of dispersant α, and 5% by mass of dispersant ζ were mixed, and the resulting mixture was mixed with 0.3 mmφ ZrO ₂ beads. The mixture was loaded into a paint shaker and subjected to crushing treatment for 1 hour to obtain a coating film-forming aqueous dispersion A-ζ according to Example 19.
Here, the dispersant ζ is a nonionic dispersant that does not have acidic or basic functional groups and has an acid value of less than 1 mgKOH/g and a base value of less than 1 mgKOH/g.

The procedure was the same as in Example 1, except that the aqueous dispersion A-ζ for forming a coating film according to Example 19 was used instead of the aqueous dispersion A for forming a coating film, and the dropping time of the surface treatment diluent was changed. By performing the operations, a surface-treated infrared absorbing fine particle dispersion according to Example 19 was prepared. Then, the same evaluation as in Example 1 was performed on the surface-treated infrared absorbing fine particle dispersion according to Example 19. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Comparative example 1]
10% by mass of hexagonal cesium tungsten bronze powder and 90% by mass of pure water were mixed, and the resulting mixture was loaded into a paint shaker containing 0.3mmφZrO ₂ beads, and pulverized and dispersed for 4 hours to obtain a comparative example. An aqueous dispersion for forming a coating film according to No. 1 was obtained.
The dispersed particle diameter of the infrared absorbing fine particles in the obtained dispersion was measured in the same manner as in Example 1, and was found to be 100 nm. In addition, as settings for particle size measurement, the particle refractive index was set to 1.81, and the particle shape was set to be non-spherical. Further, the background was measured using water, and the solvent refractive index was set to 1.33. Further, the solvent of the obtained dispersion was removed to obtain hexagonal cesium tungsten bronze fine particles according to Comparative Example 1. The crystallite diameter of the obtained hexagonal cesium tungsten bronze fine particles according to Comparative Example 1 was measured in the same manner as in Example 1, and was found to be 32 nm.

The infrared absorbing fine particle dispersion according to Comparative Example 1 was directly used without adding the surface treatment diluent dropwise to the aqueous dispersion for forming a coating film according to Comparative Example 1.
The infrared absorbing fine particle dispersion liquid according to Comparative Example 1 was evaluated in the same manner as in Example 1. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Comparative Examples 2 to 5]
Instead of hexagonal cesium tungsten bronze powder, cubic sodium tungsten bronze powder with Na/W (molar ratio) = 0.33 (Comparative Example 2), hexagonal potassium tungsten with K/W (molar ratio) = 0.33 Except for using bronze powder (Comparative Example 3), hexagonal rubidium tungsten bronze powder with Rb/W (molar ratio) = 0.33 (Comparative Example 4), and W ₁₈ O ₄₉ in Magneli phase (Comparative Example 5). By performing the same operation as in Comparative Example 1, aqueous dispersions for forming coating films according to Comparative Examples 2 to 5 were obtained.

The infrared absorbing fine particle dispersions according to Comparative Examples 2 to 5 were directly used without adding the surface treatment diluent dropwise to the aqueous dispersions for forming coating films according to Comparative Examples 2 to 5.
The obtained infrared absorbing fine particle dispersions according to Comparative Examples 2 to 5 were evaluated in the same manner as in Example 1. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[Comparative example 6]
10% by mass of hexagonal cesium tungsten bronze powder and 90% by mass of pure water were mixed, and the resulting mixed solution was loaded into a paint shaker containing 0.3mmφZrO ₂ beads, and pulverized and dispersed for 2 hours to obtain a comparative example. An aqueous dispersion for forming a coating film according to No. 6 was obtained.
The dispersed particle diameter of the infrared absorbing fine particles in the obtained dispersion was measured and found to be 180 nm. In addition, as settings for particle size measurement, the particle refractive index was set to 1.81, and the particle shape was set to be non-spherical. The background was measured using water, and the solvent refractive index was set to 1.33.
Further, the solvent of the obtained dispersion was removed to obtain hexagonal cesium tungsten bronze fine particles according to Comparative Example 6. The crystallite diameter of the obtained hexagonal cesium tungsten bronze fine particles according to Comparative Example 6 was measured in the same manner as in Example 1, and was found to be 60 nm.

A surface treatment diluent was not added dropwise to the aqueous dispersion for forming a coating film according to Comparative Example 6, and the infrared absorbing fine particle dispersion according to Comparative Example 6 was directly used.
The same evaluation as in Example 1 was performed on the infrared absorbing fine particle dispersion according to Comparative Example 6. The manufacturing conditions and evaluation results are shown in Tables 1 to 3.

[summary]
Surface-treated infrared absorbing fine particle dispersions using hexagonal cesium tungsten bronze with visible light transmittance set to 80% according to Examples 1 to 7 and 12 to 19 of the present invention were exposed to an air atmosphere at 85°C for 24 hours. As a result, it was found that the film had excellent heat and humidity resistance, with the amount of change in solar transmittance before and after the exposure being 2.0% or less.
In addition, a surface-treated infrared absorbing fine particle dispersion using cubic sodium tungsten bronze, hexagonal potassium tungsten bronze, hexagonal rubidium tungsten bronze, and Magnelli phase W ₁₈ O ₄₉ according to Examples 8 to 11 as the infrared absorbing fine particles, It was found to have excellent heat and humidity resistance.

On the other hand, infrared absorbing fine particle dispersions using hexagonal cesium tungsten bronze with visible light transmittance set to 80% according to Comparative Examples 1 to 6 using infrared absorbing fine particles without surface treatment were heated at 85°C. When exposed to the atmosphere for 24 hours, the amount of change in solar transmittance before and after the exposure was 7.4% or more, indicating that the heat and humidity resistance was poor.

11. WO Octahedron formed by ₆ units 12. element M

Claims (13)

A surface-treated infrared-absorbing fine particle dispersion liquid in which surface-treated infrared-absorbing fine particles are dispersed in a solvent containing water,
The surface-treated infrared absorbing fine particles have a surface containing a hydrolyzed product of a metal chelate compound, a polymer of a hydrolyzed product of a metal chelate compound, a hydrolyzed product of a metal cyclic oligomer compound, or a metal cyclic oligomer compound. is coated with a coating film containing one or more selected from the following:
The dispersed particle diameter of the surface-treated infrared absorbing fine particles is 20 nm or more and 400 nm or less,
The surface-treated infrared absorbing fine particle dispersion further contains one or more dispersants,
A surface-treated infrared absorbing fine particle dispersion, wherein the dispersant has an acid value of 10 mgKOH/g or more and contains a phosphoric acid or carboxylic acid functional group . The surface-treated infrared absorbing fine particle dispersion liquid according to claim 1, wherein the dispersant further includes a nonionic dispersant having an acid value of less than 1 mgKOH/g. The surface-treated infrared-absorbing fine particle dispersion according to claim 1 or 2, wherein the surface-treated infrared-absorbing fine particle dispersion has a pH value of 4 or more and 10 or less. The surface-treated infrared ray according to any one of claims 1 to 3, wherein the concentration of the surface-treated infrared-absorbing fine particles in the surface-treated infrared-absorbing fine particle dispersion is 0.01% by mass or more and 80% by mass or less. Absorbent fine particle dispersion. The surface according to any one of claims 1 to 4, wherein the metal chelate compound and the metal cyclic oligomer compound contain one or more metal elements selected from Al, Zr, Ti, Si, and Zn. Treated infrared absorbing fine particle dispersion. The surface treatment according to any one of claims 1 to 5, wherein the metal chelate compound and the metal cyclic oligomer compound have one or more selected from ether bonds, ester bonds, alkoxy groups, and acetyl groups. Infrared absorbing fine particle dispersion. The infrared absorbing fine particles have the general formula WyOz (where W is tungsten, O is oxygen, 2.2≦z/y≦2.999), or/and the general formula MxWyOz (where M is 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 One or more elements selected from the following: W is tungsten, O is oxygen, infrared absorbing fine particles expressed as 0.001≦x/y≦1, 2.0≦z/y≦3.0 The surface-treated infrared absorbing fine particle dispersion according to any one of claims 1 to 6, characterized in that: The surface-treated infrared absorbing fine particle dispersion according to claim 7, wherein the M is one or more elements selected from Cs, K, Rb, Tl, In, and Ba. The surface-treated infrared absorbing fine particle dispersion according to claim 1 , wherein the infrared absorbing fine particles are tungsten oxide fine particles and/or composite tungsten oxide fine particles having a hexagonal crystal structure. liquid. The surface-treated infrared-absorbing fine particle dispersion according to any one of claims 1 to 9, wherein the surface-treated infrared-absorbing fine particle dispersion further contains one or more water-soluble organic substances. 11. The surface-treated infrared absorbing fine particle dispersion according to claim 1, wherein the water-soluble organic substance is one or more selected from alcohols, glycols, and water-soluble resins. a step of dispersing infrared absorbing fine particles in a solvent containing water to obtain an aqueous dispersion for forming a coating film;
A metal chelate compound and/or a metal cyclic oligomer compound is added to the aqueous dispersion for coating film formation, and the surface of the infrared absorbing fine particles is polymerized with a hydrolysis product of the metal chelate compound and a hydrolysis product of the metal chelate compound. The surface-treated infrared absorbing fine particles are coated with a coating film containing one or more selected from the group consisting of a hydrolyzed product of a metal cyclic oligomer compound, a polymer of a hydrolyzed product of a metal cyclic oligomer compound, and then treated with water. and obtaining a surface-treated infrared-absorbing fine particle dispersion in which the surface-treated infrared-absorbing fine particles are dispersed in a solvent containing a dispersant .
However, the dispersant has an acid value of 10 mgKOH/g or more and contains a phosphoric acid or carboxylic acid functional group. 13. The method for producing a surface-treated infrared absorbing fine particle dispersion according to claim 12, wherein the dispersant further includes a nonionic dispersant having an acid value of less than 1 mgKOH/g.