JP5034272B2 - Tungsten-containing oxide fine particles, method for producing the same, and infrared shielding body using the same - Google Patents

Description

  The present invention provides tungsten-containing oxide fine particles obtained by further adding a specific element or a compound thereof to tungsten oxide fine particles or composite tungsten oxide fine particles that transmit light in the visible light region and absorb light in the near infrared region. The present invention relates to a manufacturing method thereof, and an infrared shielding body using the same.

  As light-shielding members used in window materials, etc., inorganic pigments such as carbon black and titanium black that have absorption characteristics from the visible light region to the near infrared region, and organic materials such as aniline black that have strong absorption properties only in the visible light region A light shielding film containing a black pigment including a pigment and the like, and a half mirror type light shielding member in which a metal such as aluminum is vapor-deposited have been proposed.

  In Patent Document 1, on a transparent glass substrate, at least one metal ion selected from the group consisting of Group IIIa, Group IVa, Group Vb, Group VIb and Group VIIb of the periodic table as a first layer from the substrate side. A composite tungsten oxide film containing, a transparent dielectric film as a second layer on the first layer, a third layer on the second layer as a group IIIa, IVa group, Vb group of the periodic table, A composite tungsten oxide film containing at least one metal ion selected from the group consisting of Group VIb and Group VIIb is provided, and the refractive index of the transparent dielectric film of the second layer is set to the first layer and the third layer. Infrared shielding glass that can be suitably used for parts requiring high visible light transmittance and good infrared shielding performance by lowering the refractive index of the composite tungsten oxide film of the layer is proposed. To have.

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

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

In Patent Document 4, tungsten trioxide (WO ₃ ), molybdenum trioxide (MoO ₃ ), niobium pentoxide (Nb ₂ O ₅ ), tantalum pentoxide (Ta) containing an additive material such as hydrogen, lithium, sodium, or potassium. ₂ O ₅ ), a metal oxide film selected from one or more of vanadium pentoxide (V ₂ O ₅ ) and vanadium dioxide (VO ₂ ) is coated by a CVD method or a spray method and thermally decomposed at about 250 ° C. There has been proposed a solar control glass sheet having solar light shielding properties formed in this manner.

  Further, the present inventor disclosed in Patent Document 5 an infrared shielding material fine particle dispersion in which infrared shielding material fine particles are dispersed in a medium, and the infrared shielding material fine particles have a general formula WyOz (where W is tungsten, O is oxygen, fine particles of tungsten oxide represented by 2.2 ≦ z / y ≦ 2.999, or / and general formula MxWyOz (where M is H, He, alkali metal, alkaline earth metal) , 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, One or more types selected from Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I Elements, W is tungsten, O is oxygen 0.001 ≦ x / y ≦ 1, 2.2 ≦ z / y ≦ 3.0), wherein the particle diameter of the infrared shielding material fine particles is 1 nm or more and 800 nm or less The optical properties, conductivity, and production method of the infrared shielding material fine particle dispersion characterized by the above are disclosed.

JP-A-8-59300 JP-A-8-12378 JP-A-8-283044 JP 2000-1119045 A International Publication WO2005 / 37932

Using an infrared shielding material in which tungsten oxide fine particles or composite tungsten oxide fine particles are dispersed, light in the visible light region is transmitted and light in the near infrared region is absorbed.
The tungsten oxide fine particles and / or the composite tungsten oxide fine particles are colored (however, this coloring has a property of returning to the original state when left for a long time (several days)), and the light transmittance in the visible light region is reduced. A problem has been found that may change (decrease).

The inventors of the present invention have studied the cause of the coloring, and have come up with the idea that the tungsten oxide fine particles and / or the composite tungsten oxide fine particles are colored by ultraviolet rays.
Therefore, the problem to be solved by the invention is to provide tungsten oxide fine particles, composite tungsten oxide fine particles that do not cause a coloring phenomenon even when irradiated with ultraviolet rays, a method for producing the same, and the tungsten oxide fine particles. The present invention provides an infrared shielding body using composite tungsten oxide fine particles.

  Tungsten trioxide is a wide bandgap oxide, hardly absorbs light in the visible light region, and has no free electrons (conduction electrons) in its structure. However, it is known that a small amount of oxygen is reduced from tungsten trioxide or a so-called tungsten bronze in which a positive element such as Na is added to tungsten trioxide, free electrons are generated and conductivity is exhibited. A small amount of oxygen is reduced from tungsten trioxide, and tungsten bronze with a positive element added to tungsten trioxide is recognized to absorb light in the visible light region. As it was not used.

  The present inventors, as shown in Patent Document 8, because tungsten trioxide has a wide band gap, using this tungsten trioxide skeleton structure, reducing the oxygen content of this tungsten trioxide, Alternatively, conduction electrons (free electrons) are generated by adding cations, and the particle diameter and shape of the tungsten oxide particles and composite tungsten oxide particles are controlled to transmit light in the visible light region. The particle | grains which have property were produced, and it came to obtain the visible light transmission type particle dispersion using this.

  However, in the fine particle dispersion using the tungsten oxide fine particles and / or the composite tungsten oxide fine particles, the tungsten oxide used and / or the composite tungsten oxide is colored by ultraviolet rays, and the dispersion There was a phenomenon that the transmittance changed (decreased) in the body.

The present inventors have conducted many tests to suppress the above coloring phenomenon, and have the general formula W _y O _z (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999). Tungsten oxide fine particles represented and / or general formula M _x WO ₃ (where M element is selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, Na) One or more kinds of elements, W is tungsten, O is oxygen, and in the crystal of composite tungsten oxide fine particles represented by 0.001 ≦ X ≦ 1) and / or on the surface of the fine particles, Cu, Fe, Mn The addition of at least one element selected from Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb or a compound thereof suppresses the coloring phenomenon. The headline, the present invention has been reached.

That is, in order to solve the above-described problem, the first configuration is
Tungsten oxide fine particles represented by the general formula W _y O _z (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999), or / and the general formula M _x WO ₃ (where , M is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, and Na, W is tungsten, O is oxygen, 0.001 ≦ One or more fine particles selected from composite tungsten oxide fine particles represented by X ≦ 1),
One or more elements selected from Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb, or compounds thereof exist on the surface of the fine particles. It is the tungsten containing oxide fine particle characterized by being.

The second configuration is
The tungsten-containing oxide fine particles according to the first configuration, wherein the tungsten oxide fine particles have a general formula W _y O _Z (W is tungsten, O is oxygen, 2.45 ≦ z / y ≦ 2. 999), a tungsten-containing oxide fine particle characterized by including a magnesium phase having a composition ratio represented by 999).

The third configuration is
The tungsten-containing oxide fine particles according to the first or second configuration, wherein the composite tungsten oxide fine particles represented by M _x WO ₃ has an amorphous structure, a cubic structure, a tetragonal structure, or a hexagonal structure. A tungsten-containing oxide fine particle characterized by containing a tungsten bronze structure.

The fourth configuration is
The tungsten-containing oxide fine particles according to any one of the first to third configurations,
The tungsten-containing oxide fine particles are characterized in that the fine particles are blue, green, or black.

The fifth configuration is
An infrared shielding body, wherein the tungsten-containing oxide fine particles according to any one of the first to fourth configurations are dispersed in a medium.

The sixth configuration is
It is an infrared shielding body as described in 5th structure, Comprising: The said medium is transparent resin or glass, It is an infrared shielding body characterized by the above-mentioned.

The seventh configuration is
Tungsten oxide fine particles represented by the general formula W _y O _z (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999), or / and the general formula M _x WO ₃ (where , M is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, and Na, W is tungsten, O is oxygen, 0.001 ≦ In the composite tungsten oxide fine particles represented by X ≦ 1), one or more kinds selected from Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb A tungsten-containing oxide fine particle is produced by adding an element or a compound thereof and mixing them uniformly, followed by heat treatment in a reducing gas atmosphere at 600 ° C. or lower to produce a tungsten-containing oxide fine particle. Direction It is.

The eighth configuration is
Tungsten oxide fine particles represented by the general formula W _y O _z (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999), or / and the general formula M _x WO ₃ (where , M is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, and Na, W is tungsten, O is oxygen, 0.001 ≦ X ≦ 1) composite tungsten oxide fine particles, and one or more selected from Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb This is a method for producing tungsten-containing oxide fine particles, characterized in that an element or a compound thereof is vigorously mixed using a medium stirring mill to produce tungsten-containing oxide fine particles.

  The tungsten-containing oxide fine particles according to any one of the first to fourth configurations described above have UV resistance properties, and coloring when subjected to ultraviolet irradiation is suppressed. Therefore, the tungsten-containing oxide fine particles stably transmit light in the visible light region under the light containing various light rays such as ultraviolet rays, visible rays, and infrared rays like sunlight rays, and near infrared rays. Area light is industrially effective in the field of shielding.

  The infrared shielding body according to the fifth or sixth configuration has UV resistance characteristics, and coloring when subjected to ultraviolet irradiation is suppressed. Therefore, the infrared shielding body stably transmits light in the visible light region under light including various light rays such as ultraviolet rays, visible light rays, and infrared rays, like sunlight. Light is industrially effective in shielding applications.

All of the methods for producing tungsten-containing oxide fine particles according to the seventh or eighth configuration are industrially easy methods. Therefore, tungsten-containing oxide fine particles with improved UV resistance can be manufactured easily and with high productivity while transmitting light in the visible light region and absorbing light in the near infrared region.

Hereinafter, the tungsten-containing oxide fine particles will be described in detail.
1. Tungsten oxide, the composite tungsten oxide general, because there is no valid free electrons in WO _3, WO ₃ is less absorption reflection characteristics in the near infrared region, is not effective as an infrared-shielding material. Here, it is known that free electrons are generated in WO ₃ by reducing the ratio of oxygen to tungsten in WO ₃ from ₃ , and the inventors have proposed that the composition of tungsten and oxygen is as follows. It has been found that there is a particularly effective range as an infrared shielding material in a specific part of the range.

The composition range of tungsten and oxygen is such that the composition ratio of oxygen to tungsten is 3 or less, and 2.2 ≦ z / y ≦ 2.999 when the infrared shielding material is described as WyOz. Is preferred. 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 other than the objective in the infrared ray shielding material, and the chemical stability as the material. Therefore, it can be applied as an effective infrared shielding material. On the other hand, if the value of z / y is 2.999 or less, a required amount of free electrons is generated, and an efficient infrared shielding material is obtained.

  In addition, in the tungsten oxide fine particles represented by the general formula WyOz, a so-called “Magneli phase” having a composition ratio represented by 2.45 ≦ z / y ≦ 2.999 is chemically stable, and a near infrared ray. Since the region has good absorption characteristics, it is preferable as an infrared shielding material.

Further, the element M (wherein the M element is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, and Na) is added to the WO _3. Addition is preferable because free electrons are generated in WO ₃ and free electron-derived absorption characteristics are expressed in the near-infrared region, which is effective as a near-infrared absorbing material near 1000 nm. Here, from the viewpoint of stability in the WO ₃ to which the element M is added, the M element is selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, and Na. One or more elements are preferred.

The infrared shielding material to which the element M for generating free electrons is added has a general formula of M _x WO ₃ (where the M element is Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr). In addition, one or more elements selected from Na, W is tungsten, O is oxygen, and an infrared shielding material represented by 0.001 ≦ X ≦ 1) is desirable.

  First, the value x indicating the amount of element M added will be described. If the value of x is larger than 0.001, a sufficient amount of free electrons is generated, and the intended infrared shielding effect can be obtained. As the amount of the element M added is increased, the supply amount of free electrons is increased and the infrared shielding efficiency is increased. Further, it is preferable that the value of x is smaller than 1 because it is possible to avoid the generation of an impurity phase in the infrared shielding material. The element 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 are preferably at least one selected from the group consisting of

Here, from the viewpoint of stability in the MxWO ₃ to which the element M is added, the element M is an alkali metal, an alkaline earth metal, a rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, More preferably, it is one or more elements selected from Te, Ti, Nb, V, Mo, Ta, and Re. From the viewpoint of improving the optical properties and weather resistance as an infrared shielding material, More preferably, the element M belongs to an alkaline earth metal element, a transition metal element, a group 4B element, or a group 5B element.

Furthermore, when the composite tungsten oxide fine particles described above have a hexagonal crystal structure, transmission of the fine particles in the visible light region is improved, and absorption in the near infrared region is improved. This will be described with reference to FIG. 1, which is a schematic plan view of the hexagonal crystal structure. In FIG. 1, six octahedrons formed of WO ₆ units denoted by reference numeral 1 are assembled to form a hexagonal void, and an element M denoted by reference symbol 2 is arranged in the void to form one piece. The unit is composed of a large number of one unit and a hexagonal crystal structure is formed.

In order to improve the transmittance in the visible light region and improve the absorption characteristics in the near infrared region in this embodiment, the unit structure (WO ₆₎ described in FIG. It is sufficient that six octahedrons formed as a unit are assembled to form a hexagonal void, and the element M is arranged in the void), and the composite tungsten oxide fine particles are crystalline. Or amorphous.

When the cation of the element M is added to the hexagonal void, the transmittance in the visible light region is improved, and the absorption characteristics in the near infrared region are improved. Here, generally, the hexagonal crystal is formed when the element M having a large ionic radius is added, and specifically, the hexagonal crystal is formed when Cs, K, Rb, Tl, In, Ba, Sn is added. It is preferable because it is easily formed. Of course, there is no problem with the above-described elements other than these because the additive element M can exist in the hexagonal void formed by the WO ₆ unit.

  When the composite tungsten oxide fine particles having a hexagonal crystal structure have a uniform crystal structure, the addition amount of the additive element M is preferably 0.2 or more and 0.5 or less, more preferably 0.33 in terms of x. It is. When the value of x is 0.33, it is considered that the additive element M is arranged in all of the hexagonal voids.

  Besides hexagonal crystals, tetragonal and cubic tungsten bronzes are also effective as infrared shielding materials. The absorption position in the near infrared region tends to change depending on the crystal structure, and the absorption position tends to move the tetragonal crystal to the longer wavelength side than the cubic crystal and the hexagonal crystal to move to the longer wavelength side than the tetragonal crystal. There is. Concomitantly, the absorption characteristic in the visible light region is the smallest in hexagonal crystals, followed by tetragonal crystals, and cubic crystals are the largest among them. Therefore, hexagonal tungsten bronze is preferably used for the purpose of transmitting light in the visible light region and shielding light in the infrared region. However, the tendency of the optical characteristics described here is merely a rough tendency, and changes depending on the kind of additive element, the amount of addition, and the amount of oxygen, and the present invention is not limited to this.

  In the present embodiment, the tungsten oxide fine particles and / or the composite tungsten oxide fine particles absorb a large amount of light in the near-infrared region, particularly in the vicinity of 1000 nm, so that the transmitted color tone is often from blue to green. . Moreover, the particle diameter of the particle | grains of the said infrared shielding material can each be selected according to the intended purpose. First, when using for the application which maintained transparency, it is preferable to have a particle diameter of 800 nm or less. This is because particles smaller than 800 nm do not completely block light due to scattering, and can maintain visibility in the visible light region and at the same time efficiently maintain transparency. In particular, when importance is attached to transparency in the visible light region, it is preferable to further consider scattering by particles.

  When importance is attached to the reduction of scattering by the particles, the particle diameter is 200 nm or less, preferably 100 nm or less. The reason is that if the particle size of the particles is small, the scattering of light in the visible light region of 400 nm to 780 nm due to geometric scattering or Mie scattering is reduced, and as a result, the infrared shielding film becomes like a frosted glass and is clear and transparent. This is because it is possible to avoid the loss of sex. That is, when the particle diameter is 200 nm or less, the geometric scattering or Mie scattering is reduced, and a Rayleigh scattering region is obtained. This is because in the Rayleigh scattering region, the scattered light is reduced in inverse proportion to the sixth power of the particle diameter, so that the scattering is reduced and the transparency is improved as the particle diameter is reduced. Further, when the particle diameter is 100 nm or less, the scattered light is preferably extremely small. From the viewpoint of avoiding light scattering, a smaller particle diameter is preferable. If the particle diameter is 1 nm or more, industrial production is easy.

  By selecting the particle size to be 800 nm or less, the haze value of the infrared shielding material fine particle dispersion in which the infrared shielding material fine particles are dispersed in the medium can be set to a visible light transmittance of 85% or less and a haze of 30% or less. . If the haze is greater than 30%, it becomes like frosted glass, and clear transparency cannot be obtained.

  Since the above tungsten oxide and composite tungsten oxide have little absorption in the visible light region and large absorption in the near infrared region, they are effective as a visible light transmission type infrared shielding material for heat insulation of windows and the like.

2. Tungsten oxide, method for producing composite tungsten oxide, tungsten oxide fine particles represented by the above general formula W _y O _z (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999), And / or MxWO ₃ (wherein M element is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, Na, W is tungsten, O is oxygen, and composite tungsten oxide fine particles represented by 0.001 ≦ X ≦ 1) can be obtained by heat-treating a tungsten compound starting material in an inert gas atmosphere or a reducing gas atmosphere.

  As the tungsten compound starting material, tungsten trioxide powder, tungsten dioxide powder, or hydrated tungsten oxide, tungsten hexachloride powder, ammonium tungstate powder, or tungsten hexachloride was dissolved in alcohol. Tungsten oxide hydrate powder obtained by post-drying, or tungsten oxide hydrate powder obtained by dissolving tungsten hexachloride in alcohol and then adding water to precipitate it and drying it Or any one or more selected from a tungsten compound powder obtained by drying an ammonium tungstate aqueous solution and a metal tungsten powder.

  Here, in the case of producing tungsten oxide fine particles, from the viewpoint of ease of the production process, tungsten oxide hydrate powder, tungsten trioxide, or tungsten compound powder obtained by drying ammonium tungstate aqueous solution, More preferably, is used. Further, when producing composite tungsten oxide fine particles, it is more preferable to use an ammonium tungstate aqueous solution or a tungsten hexachloride solution from the viewpoint that each element whose starting material is a solution can be easily mixed uniformly. These raw materials are used and heat-treated in an inert gas atmosphere or a reducing gas atmosphere to obtain infrared shielding material fine particles containing tungsten oxide fine particles having the above-mentioned particle diameter and / or composite tungsten oxide fine particles. be able to.

The infrared shielding material fine particles containing the composite tungsten oxide fine particles represented by the general formula M _x WO ₃ containing the element M are the infrared shielding material containing the tungsten oxide fine particles represented by the general formula WyOz described above. The starting material is a tungsten compound containing the element M in the form of a single element or a compound.

  Here, in order to produce a starting material in which each component is uniformly mixed at the molecular level, it is preferable to mix each material with a solution, and the tungsten compound starting material containing the element M is dissolved in a solvent such as water or an organic solvent. Preferably it is possible. Examples include tungstate, chloride, nitrate, sulfate, oxalate, oxide, carbonate, hydroxide, etc. containing element M, but are not limited to these and are in solution form Is preferable.

Here, the heat treatment condition in the inert atmosphere is preferably 650 ° C. or higher. The starting material heat-treated at 650 ° C. or higher has a sufficient near-infrared absorbing power and is efficient as infrared shielding fine particles. As the inert gas, an inert gas such as Ar or N ₂ is preferably used. As the heat treatment conditions in the reducing atmosphere, first, the starting material is heat-treated at 100 ° C. to 650 ° C. in the reducing gas atmosphere, and then heat-treated at a temperature of 650 ° C. to 1200 ° C. in an inert gas atmosphere. Good to do. The reducing gas at this time is not particularly limited, but H ₂ is preferable. When H ₂ is used as the reducing gas, the composition of the reducing atmosphere is preferably such that, for example, H ₂ is mixed with an inert gas such as Ar or N _{2 at a} volume ratio of 0.1% or more. Is preferably mixed at 0.2% or more. H ₂ can be advanced efficiently reduced if more than 0.1% by volume.

The raw material powder reduced with hydrogen contains a magnetic phase, exhibits good infrared shielding properties, and can be used as infrared shielding particles in this state. However, since hydrogen contained in tungsten oxide is unstable, application may be limited in terms of weather resistance. Therefore, a more stable infrared shielding fine particle can be obtained by heat-treating the tungsten oxide compound containing hydrogen at 650 ° C. or higher in an inert atmosphere. The atmosphere during the heat treatment at 650 ° C. or higher is not particularly limited, but N ₂ and Ar are preferable from an industrial viewpoint. By the heat treatment at 650 ° C. or higher, a Magneli phase is obtained in the infrared shielding fine particles, and the weather resistance is improved.

3. Coloring of tungsten oxide and composite tungsten oxide with ultraviolet rays When the above tungsten oxide or composite tungsten oxide is irradiated with light in the ultraviolet region (sometimes referred to as UV light), the visible light region changes to the near infrared region. The transmittance across the area is reduced. The cause of this is not clear, but it is thought that the so-called optical intercalation effect has an influence. Since the band gap of the material is in the ultraviolet region, electrons and holes are generated on the surface of the material when irradiated with ultraviolet light. This alone does not cause a significant change, but the adsorbed water on the surface of this (composite) tungsten oxide is protonated by holes, and the generated electrons and H + are taken into the (composite) tungsten oxide, thereby conducting electrons. It is considered that light in the visible to near-infrared region is more absorbed by the plasma absorption, and the transmittance is reduced.

  The inventors have found that when an ultraviolet curable resin or the like is used as a binder, coloring by ultraviolet rays appears remarkably. This is presumed to be because radicals are generated in the resin by ultraviolet rays, and these radicals become the generation sources of electrons and holes, and the coloring phenomenon is promoted.

4). In order to suppress the above-mentioned coloring by ultraviolet rays, in the present embodiment, the general formula W _y O _z (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999). ) And / or a general formula M _x WO ₃ (wherein M element is Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, Na) One or more elements selected from the group consisting of W, tungsten, O, oxygen, 0.001 ≦ X ≦ 1) in the crystal of the composite tungsten oxide fine particles or / and on the surface of the fine particles, Cu, Fe One or more elements selected from Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb or a compound thereof are added.

In addition, the tungsten oxide fine particles include a magnesium phase having a composition ratio represented by the general formula W _y O _Z (W is tungsten, O is oxygen, 2.45 ≦ z / y ≦ 2.999). It is characterized by.

Further, the composite tungsten oxide fine particles represented by M _x WO ₃ are characterized in that the crystal structure includes an amorphous structure or a cubic, tetragonal or hexagonal tungsten bronze structure.

The reason for improving the UV resistance by adding the above additive element or its compound has not been elucidated, but when the above additive element or its compound is present on the (composite) tungsten oxide surface, these cause the entry of H ⁺ . It is thought that there is an effect to prevent. In addition, when the additive element is present on the surface of the (composite) tungsten oxide in a metal state, it is considered that there is an effect of neutralizing radicals and H + by catalytic action. In addition, when the additive element is present in the crystal of the (composite) tungsten oxide fine particles, it is considered that coloring due to ultraviolet rays is reduced due to an effect of structurally or electrostatically preventing the entry of H ⁺ or the like. .

5. Method for Producing Tungsten Oxide and Composite Tungsten Oxide with Additive Element Added Tungsten-containing oxide fine particles that are suppressed from being colored by ultraviolet rays have a general formula W _y O _z (W is tungsten, O is oxygen, 2. 2 ≦ z / y ≦ 2.999) or / and the general formula M _x WO ₃ (wherein the M element is Cs, Rb, K, Tl, Ba, In, Li, One or more elements selected from Sn, Ca, Sr, and Na, W is tungsten, O is oxygen, and in the crystal of the composite tungsten oxide fine particles represented by 0.001 ≦ X ≦ 1) and / or The fine particle surface contains one or more elements selected from Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb or compounds thereof. The features.

  1) The tungsten-containing oxide fine particles of the present embodiment are obtained by adding Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In to the raw materials for the above-described tungsten oxide fine particles and composite tungsten oxide fine particles. One or more elements selected from Sn, Cs, and Rb or a compound thereof are added, and the mixture is heat-treated at 100 ° C. or higher and 850 ° C. or lower in a reducing gas atmosphere. It is obtained by heat treatment at a temperature of 450 ° C. or higher and 1200 ° C. or lower in an inert gas atmosphere.

If the heat treatment in the reducing gas atmosphere is 100 ° C. or higher, the tungsten oxide and composite tungsten oxide fine particles of the present invention are obtained, and if it is 850 ° C. or lower, the formation of tungsten dioxide other than the object of the present invention is suppressed. Therefore, it is preferable. The reducing gas is not particularly limited preferably H _2. When H ₂ is used as the reducing gas, it is preferable that the composition of the reducing atmosphere includes, for example, 0.1% or more by volume of H _{2 in} an inert gas such as Ar or N _2. More preferably, 2% or more is good. H ₂ can be advanced efficiently reduced if more than 0.1% by volume.

In an atmosphere containing oxygen, tungsten oxide fine particles and composite tungsten oxide fine particles are not generated, and WO ₃ is generated. This is not preferable because there is no absorption characteristic in the near infrared region. Further, if the heat treatment in an inert gas atmosphere to be performed next is 450 ° C. or higher, crystallinity is improved, and it is preferable to be 1200 ° C. or lower because coarse particle growth and volatilization of additive elements are suppressed. As the inert gas atmosphere, Ar, N ₂ or the like is preferable.

  Thus, when a compound containing an additive element is added during the production of tungsten oxide fine particles and composite tungsten oxide fine particles, the additive element precipitates on the particle surface when the tungsten oxide fine particles and composite tungsten oxide fine particles are produced. Further, the additive element enters the tungsten oxide fine particles and the composite tungsten oxide fine particles, which is effective in improving the UV resistance.

2) As another method, the above-described tungsten oxide fine particles and composite tungsten oxide fine particles may be added to Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb. One or more elements selected from the above or a compound thereof are added and mixed uniformly, and then heat-treated at 100 ° C. to 1000 ° C. in a reducing gas atmosphere, whereby the tungsten-containing oxide of the present embodiment Fine particles can be obtained. If the heat treatment in a reducing gas atmosphere is 100 ° C. or higher, the above element is preferably diffused on the surface of the tungsten oxide or composite tungsten oxide fine particles, whereas if it is 1000 ° C. or lower, the element generates a compound other than the intended compound. It is preferable. The reducing gas is not particularly limited preferably H _2. When H ₂ is used as the reducing gas, the composition of the reducing atmosphere is preferably such that, for example, H ₂ is mixed with an inert gas such as Ar or N _{2 at a} volume ratio of 0.1% or more. More preferably, 2% or more is good. H ₂ can be advanced efficiently reduced if more than 0.1% by volume.

  When the tungsten oxide fine particles and / or the composite tungsten oxide fine particles are produced in advance by the above method and dispersed or pulverized with a bead mill or the like, the addition of an additive element or a compound of the additive element improves the UV resistance. A tungsten oxide is obtained. This is because the additive element diffuses into the fine particles of tungsten oxide and / or composite tungsten oxide fine particles in the process of being pulverized and mixed with strong energy, and both compounds are formed on the fine particle surface. It is thought that it is effective in improving the UV resistance.

  3) Further, as another method, the above-mentioned tungsten oxide fine particles, composite tungsten oxide fine particles, and Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb are used. One or more selected additive elements or compounds thereof can be obtained by vigorously mixing using a medium stirring mill. As described above, tungsten oxide fine particles and composite tungsten oxide fine particles are manufactured in advance, and the additive element or a compound containing the same is further added to this, followed by heat treatment, whereby the additive element compound or The additive element metal is deposited.

  As a mixing method, tungsten oxide fine particles, composite tungsten oxide fine particles, and solid additive element compounds may be directly mixed, and the additive element compound is dispersed in a dispersion of tungsten oxide fine particles and composite tungsten oxide fine particles. It may be dissolved. In addition, when dispersed and pulverized by a medium agitating mill such as a bead mill as shown in the above method, tungsten oxide fine particles and composite tungsten oxide are added in the process of adding additive elements and compounds of the additive elements and pulverizing and mixing with strong energy. The above additive element diffuses into the material fine particles, both compounds are formed on the surface of the fine particles, and further heat treated to obtain the effect of UV resistance.

6). Color tone of tungsten oxide fine particles and / or composite tungsten oxide fine particles In the present embodiment, in the crystal of tungsten oxide fine particles or composite tungsten oxide fine particles or / and on the surface of the fine particles, Cu, Fe, Mn, Ni , Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb, tungsten-containing oxide fine particles to which one or more elements selected from the group or a compound thereof are added are in the near-infrared region, particularly 1000 to 1000. In order to absorb light around 1500 nm greatly, even if UV-resistant treatment is applied, the transmitted color tone often changes from blue to green. However, those containing Cu or noble metals change from green to achromatic (gray). Or black). Gray or black is particularly preferred as a thermal insulation material for windows.

  Although the cause of the color change is unknown in detail, the additive metal precipitates on the surface of the tungsten oxide fine particles and / or the composite tungsten oxide fine particles or forms a composite compound. The resonance frequency is affected, the absorption position is shifted to the longer wavelength side, and the color tone is expected to change.

  Further, it is known that when the so-called tungsten bronze voids are filled with metal ions on the surface of tungsten oxide fine particles and / or composite tungsten oxide fine particles, the dielectric constant decreases. For this reason, the dielectric constant (refractive index) of the surface of a particle with a metal element added to the surface decreases, and when dispersed in the medium, the difference in refractive index between the medium and the particle surface decreases, further reducing the amount of scattered light. In addition, it is possible to form an appearance that is very excellent in transparency.

7). Particle diameter of tungsten-containing oxide fine particles The particle diameter of the tungsten-containing oxide fine particles can be selected according to the purpose of use. First, when using for the application which maintained transparency, it is preferable to have a particle diameter of 800 nm or less. This is because particles smaller than 800 nm do not completely block light due to scattering, and can maintain visibility in the visible light region and at the same time efficiently maintain transparency. In particular, when importance is attached to transparency in the visible light region, it is preferable to further consider scattering by particles.

  When importance is attached to the reduction of scattering by the particles, the particle diameter is 200 nm or less, preferably 100 nm or less. The reason is that if the particle size of the particles is small, the scattering of light in the visible light region of 400 nm to 780 nm due to geometric scattering or Mie scattering is reduced, and as a result, the infrared shielding film becomes like a frosted glass and is clear and transparent. This is because it is possible to avoid the loss of sex. That is, when the particle diameter is 200 nm or less, the geometric scattering or Mie scattering is reduced, and a Rayleigh scattering region is obtained. This is because in the Rayleigh scattering region, the scattered light is reduced in inverse proportion to the sixth power of the particle diameter, so that the scattering is reduced and the transparency is improved as the particle diameter is reduced. Further, when the particle diameter is 100 nm or less, the scattered light is preferably extremely small. From the viewpoint of avoiding light scattering, a smaller particle diameter is preferable. If the particle diameter is 1 nm or more, industrial production is easy.

  By selecting the particle size to be 800 nm or less, the haze value of the infrared shielding material in which the tungsten-containing oxide fine particles are dispersed in the medium can be set to a visible light transmittance of 85% or less and a haze of 30% or less. If the haze is greater than 30%, it becomes like frosted glass, and clear transparency cannot be obtained.

8). Infrared shield As an application method of tungsten-containing oxide fine particles in the present embodiment, there is a method in which the fine particles are dispersed in an appropriate medium and formed on the surface of a desired substrate to form an infrared shield. This method allows the infrared shielding material fine particles fired at a high temperature in advance to be bound to the surface of the base material in the base material or with a binder, so that it can be applied to a base material having a low heat resistance temperature such as a resin material. There is an advantage that it is possible and inexpensive because it does not require a large-scale device for forming.

  In addition, since the tungsten-containing oxide fine particles in the present embodiment are conductive materials, when used as a continuous film, the tungsten-containing oxide fine particles have conductivity, and therefore, there is a risk of absorbing and reflecting radio waves from mobile phones and the like. is there. However, when the tungsten-containing oxide fine particles in the present embodiment are dispersed in the medium, the particles are dispersed in an isolated state, and the film loses its conductivity and exhibits radio wave permeability. Therefore, it has versatility as a window material for buildings and vehicles.

(A) Method for Dispersing Tungsten-Containing Oxide Fine Particles in Medium and Forming on Substrate Surface For example, after dispersing tungsten-containing oxide fine particles in this embodiment in an appropriate solvent and adding a binder resin thereto If the substrate surface is coated, the solvent is evaporated and the resin is cured by a predetermined method, a thin film in which the tungsten-containing oxide fine particles having infrared shielding properties are dispersed in the medium can be formed. Here, the medium is preferably a transparent resin (transparent binder resin) or glass.

  The coating method is not particularly limited as long as the resin containing tungsten-containing oxide fine particles can be uniformly coated on the surface of the substrate, and examples thereof include a bar coating method, a gravure coating method, a spray coating method, and a dip coating method. . In addition, those in which tungsten-containing oxide fine particles are directly dispersed in a binder resin do not require evaporation of the solvent after coating on the surface of the base material, and are environmentally and industrially preferable.

  As the transparent binder resin, for example, an ultraviolet curable resin, a thermosetting resin, an electron beam curable resin, a room temperature curable resin, a thermoplastic resin, or the like can be selected according to the purpose. Specifically, polyethylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polystyrene resin, polypropylene resin, ethylene vinyl acetate copolymer, polyester resin, polyethylene terephthalate resin, fluorine resin, polycarbonate resin, acrylic resin And polyvinyl butyral resin.

  Further, a binder using a metal alkoxide can be used as the glass. Representative examples of the metal alkoxide include alkoxides such as Si, Ti, Al, and Zr. A binder using these metal alkoxides can be hydrolyzed and heated to form an oxide film.

  The substrate may be a film or a board as desired, and the shape is not limited. As the transparent substrate material, PET, acrylic, urethane, polycarbonate, polyethylene, ethylene vinyl acetate copolymer, vinyl chloride, fluorine resin, and the like can be used according to various purposes. Moreover, glass other than resin can be used.

  The method for dispersing the tungsten-containing oxide fine particles in the resin is not particularly limited. For example, ultrasonic irradiation, bead mill, sand mill, or the like can be used. In order to obtain a uniform dispersion, it is also preferable to add various additives or adjust the pH.

Example 1
Tungstic acid, cesium carbonate, and copper acetate were mixed so that the molar ratio of each element was Cu: Cs: W = 0.2: 0.33: 1. This was heated at 800 ° C. for 1 hour in an atmosphere of 3% hydrogen and 97% nitrogen. The obtained composite tungsten oxide was Cs hexagonal tungsten bronze. Cu was partially deposited as a metal.
8 parts by weight of this composite tungsten oxide powder, 84 parts by weight of toluene, and 8 parts by weight of a dispersing agent were mixed and subjected to dispersion treatment with a bead mill to prepare a dispersion.
Here, the primary particle diameter of the powder after dispersion was defined as the dispersed particle diameter. The primary particle diameter was about 20 nm as a result of calculation by the Scherrer method from the measurement result of the half-value width of the X-ray diffraction measurement. .
10 parts by weight of this liquid and 5 parts by weight of an ultraviolet curable resin for hard coat (solid content: 100%) were mixed and applied onto a glass substrate using a bar coater. This film was dried at 60 ° C. for 30 seconds to evaporate the solvent, and then cured with light from a high-pressure mercury lamp to obtain an infrared shielding film.

The optical characteristics of the infrared shielding film were measured.
First, measurement was performed based on JIS R3106, and visible light transmittance and solar radiation transmittance were calculated. The haze value was measured based on JIS K 7105. The glass substrate described above is a transparent glass (thickness 2 mm) having a visible light transmittance of 92%, a solar radiation transmittance of 88%, and a haze of 0%.
As a result of the optical characteristics, it was found that the visible light transmittance was 72.44%, and the light in the visible light region was sufficiently transmitted. Further, the solar radiation transmittance was 42.44%, and the direct incident light of solar radiation. It was found that the heat insulation effect was high. Furthermore, the haze was 0.4%, and the transparency was extremely high, and the internal situation could be clearly confirmed from the outside. The transmission color tone was beautiful blue.

Next, UV resistance characteristics of the infrared shielding film were measured.
The ultraviolet irradiation test was performed using an eye UV tester (manufactured by Iwasaki Electric Co., Ltd.). The exposure conditions were an ultraviolet intensity of 100 mV / cm ² , an exposure time of 2 hours, and an exposed surface from the film surface of the sample. And the visible light transmittance difference before and behind the said exposure was measured, and it was set as UV-resistant characteristic. In addition, as mentioned above, since it is considered that coloring by ultraviolet rays returns to the original state when left for a long time, the measurement after the exposure was performed within 30 minutes from the end of the exposure.
Then, the visible light transmittance after exposure was 69.75%, and the transmittance difference before and after exposure was 2.69 points, which proved to have sufficient UV resistance characteristics.

(Example 2)
Tungstic acid and copper acetate were mixed so that the molar ratio of each element was Cu: W = 0.2: 1. This was heated at 800 ° C. for 1 hour in an atmosphere of 3% hydrogen and 5% nitrogen. The obtained tungsten oxide was a W ₁₈ O ₄₉ magnetic phase. Cu was partially deposited as a metal.
8 parts by weight of this tungsten oxide powder, 84 parts by weight of toluene, and 8 parts by weight of a dispersant were mixed and subjected to dispersion treatment with a bead mill to prepare a dispersion. It was about 20 nm as a result of calculating the primary particle diameter of the powder after dispersion | distribution from the result of the X-ray diffraction measurement by the Scherrer method. 10 parts by weight of this liquid and 5 parts by weight of an ultraviolet curable resin for hard coat (solid content: 100%) were mixed and applied onto a glass substrate using a bar coater. This film was dried at 60 ° C. for 30 seconds to evaporate the solvent, and then cured with light from a high-pressure mercury lamp to obtain an infrared shielding film.

When the optical properties of the infrared shielding film were measured in the same manner as in Example 1, it was found that the visible light transmittance was 62.30% and the light in the visible light region was sufficiently transmitted. Furthermore, the solar radiation transmittance was 47.65%, and it was found that 52% of direct incident light of sunlight was shielded and the heat insulation effect was high. Further, the haze was 0.4%, and the transparency was extremely high, and the internal situation could be clearly confirmed from the outside. The transmission color tone was beautiful blue.
As a result of investigating the UV resistance of this film in the same manner as in Example 1, the visible light transmittance after exposure was 60.92%, and the transmittance difference before and after exposure was 1.38 points. It was found to have UV characteristics.

(Example 3)
Ammonium metatungstate aqueous solution, cesium chloride, and tetrachloroauric acid tetrahydrate were mixed so that the molar ratio of each element was Au: Cs: W = 0.2: 0.33: 1. This was heated at 600 ° C. for 1 hour in an atmosphere of 3% hydrogen and 5% nitrogen, and further heat-treated at 800 ° C. for 1 hour in a nitrogen atmosphere. The obtained composite tungsten oxide was Cs hexagonal tungsten bronze. Au was partially deposited as a metal.
8 parts by weight of this composite tungsten oxide powder, 84 parts by weight of toluene, and 8 parts by weight of a dispersing agent were mixed and subjected to dispersion treatment with a bead mill to prepare a dispersion. It was about 20 nm as a result of calculating the primary particle diameter of the powder after dispersion | distribution from the result of the X-ray diffraction measurement by the Scherrer method. 10 parts by weight of this liquid and 5 parts by weight of an ultraviolet curable resin for hard coat (solid content: 100%) were mixed and applied onto a glass substrate using a bar coater. This film was dried at 60 ° C. for 30 seconds to evaporate the solvent, and then cured with light from a high-pressure mercury lamp to obtain an infrared shielding film.

When the optical properties of the infrared shielding film were measured in the same manner as in Example 1, it was found that the visible light transmittance was 72.87% and the light in the visible light region was sufficiently transmitted. Furthermore, the solar radiation transmittance was 41.62%, and it was found that about 58% of the direct incident light of sunlight was shielded, and the heat insulation effect was high. Further, the haze was 0.4%, and the transparency was extremely high, and the internal situation could be clearly confirmed from the outside. The transmission color tone was beautiful blue.
As a result of investigating the UV resistance of this film in the same manner as in Example 1, the visible light transmittance after exposure was 70.61%, and the transmittance difference before and after exposure was 2.26 points, which was sufficient. It was found to have UV characteristics.

Example 4
Ammonium metatungstate aqueous solution, cesium chloride, and hexachloroplatinic acid hexahydrate were mixed so that the molar ratio of each element was Pt: Cs: W = 0.2: 0.33: 1. This was heated at 600 ° C. for 1 hour in an atmosphere of 3% hydrogen and 5% nitrogen, and further heat-treated at 800 ° C. for 1 hour in a nitrogen atmosphere. The obtained composite tungsten oxide was Cs hexagonal tungsten bronze. Pt was partially deposited as a metal.
8 parts by weight of this composite tungsten oxide powder, 84 parts by weight of toluene, and 8 parts by weight of a dispersing agent were mixed and subjected to dispersion treatment with a bead mill to prepare a dispersion. It was about 20 nm as a result of calculating the primary particle diameter of the powder after dispersion | distribution from the result of the X-ray diffraction measurement by the Scherrer method. 10 parts by weight of this liquid and 5 parts by weight of an ultraviolet curable resin for hard coat (solid content: 100%) were mixed and applied onto a glass substrate using a bar coater. This film was dried at 60 ° C. for 30 seconds to evaporate the solvent, and then cured with light from a high-pressure mercury lamp to obtain an infrared shielding film.

The optical properties of the infrared shielding film were measured in the same manner as in Example 1. As a result, it was found that the visible light transmittance was 53.00% and sufficiently transmitted in the visible light region. Further, the solar radiation transmittance was It was 12.52%, and it was found that about 87% of the direct incident light of sunlight was shielded, and the heat insulation effect was high. Further, the haze was 0.8%, and the transparency was extremely high, and the internal situation could be clearly confirmed from the outside. The transmission color tone was bluish black.
As a result of investigating the UV resistance of this film in the same manner as in Example 1, the visible light transmittance after exposure was 48.64%, and the difference in transmittance before and after exposure was 4.36 points. It was found to have UV characteristics.

(Example 5)
Hexagonal tungsten bronze Cs _0.33 WO ₃ and sodium carbonate were mixed so that the molar ratio of each element was Na: W = 0.6: 1.
This mixture was mixed so that Cs _0.33 WO ₃ was 8 parts by weight, a dispersant was 8 parts by weight, and toluene was 80 parts by weight, and was subjected to dispersion treatment with a bead mill to prepare a dispersion. It was about 20 nm as a result of calculating the primary particle diameter of the powder after dispersion | distribution from the result of the X-ray diffraction measurement by the Scherrer method. 10 parts by weight of this liquid and 5 parts by weight of an ultraviolet curable resin for hard coat (solid content: 100%) were mixed and applied onto a glass substrate using a bar coater. This film was dried at 60 ° C. for 30 seconds to evaporate the solvent, and then cured with light from a high-pressure mercury lamp to obtain an infrared shielding film.

When the optical properties of the infrared shielding film were measured in the same manner as in Example 1, it was found that the visible light transmittance was 74.78% and the light in the visible light region was sufficiently transmitted. Further, the solar radiation transmittance was It was 38.52%, and it was found that about 61% of direct incident light of sunlight was shielded, and the heat insulation effect was high. Furthermore, the haze was 0.3%, and the transparency was extremely high, and the internal situation could be clearly confirmed from the outside. The transmitted color tone was light blue.
As a result of investigating the UV resistance of this film in the same manner as in Example 1, the visible light transmittance after exposure was 73.68%, and a transmittance difference of 1.1 before and after exposure was the point. It was found to have UV characteristics.

Example 6
Hexagonal tungsten bronze Cs _0.22 WO ₂ and copper acetate were mixed so that the molar ratio of each element was Cu: W = 0.2: 1.
Cs _0.22 WO ₂ was mixed with 20 parts by weight of Cs _0.22 WO _{2 and} 75 parts by weight of isopropyl alcohol (copper acetate was added so that Cu might be 0.2 mol with respect to W) and dispersed by a bead mill. Processed. As a result of calculating the primary particle diameter of the dispersed powder from the result of X-ray diffraction measurement by the Scherrer method, it was about 15 nm. The dispersion was dried at 120 ° C. and then heat-treated at 600 ° C. in an atmosphere of 3% hydrogen and 97% nitrogen. From the result of X-ray diffraction measurement of the obtained powder, the obtained powder was Cs hexagonal tungsten bronze and a small amount of Cu.
8 parts by weight of this Cs hexagonal tungsten bronze powder, 84 parts by weight of toluene, and 8 parts by weight of a dispersing agent were mixed and subjected to dispersion treatment with a bead mill to prepare a dispersion. It was about 20 nm as a result of calculating the primary particle diameter of the powder after dispersion | distribution from the result of the X-ray diffraction measurement by the Scherrer method. 10 parts by weight of this liquid and 5 parts by weight of an ultraviolet curable resin for hard coat (solid content: 100%) were mixed and applied onto a glass substrate using a bar coater. This film was dried at 60 ° C. for 30 seconds to evaporate the solvent, and then cured with light from a high-pressure mercury lamp to obtain an infrared shielding film.

The optical properties of the infrared shielding film were measured in the same manner as in Example 1. As a result, it was found that the visible light transmittance was 72.66% and the light in the visible light region was sufficiently transmitted. It was 37.00%, and it was found that approximately 63% of direct incident light of sunlight was shielded, and the heat insulation effect was high. Further, the haze was 0.4%, and the transparency was extremely high, and the internal situation could be clearly confirmed from the outside. The transmitted color tone was black with a faint green color. This was a good color tone close to an achromatic color.
As a result of investigating the UV resistance of this film in the same manner as in Example 1, the visible light transmittance after exposure was 71.01%, and the transmittance difference before and after exposure was 1.65 points. It was found to have UV characteristics.

(Example 7)
The _{Cs 0.22} WO ₂ hexagonal tungsten _{bronze, Cs 0.22} WO ₂ 20 parts by weight, were mixed as 80 parts by weight of isopropyl alcohol, it was Tsu was dispersed pulverized with a bead mill. As a result of calculating the primary particle diameter of the dispersed powder from the result of X-ray diffraction measurement by the Scherrer method, it was about 15 nm. Copper acetate was added to this dispersion so that Cu / W = 0.2 (molar ratio) and mixed well. This was dried at 120 ° C. and then heat-treated at 600 ° C. in an atmosphere of 3% hydrogen and 97% nitrogen. From the result of X-ray diffraction measurement of the obtained powder, the obtained powder was Cs hexagonal tungsten bronze and a small amount of Cu.
8 parts by weight of this Cs hexagonal tungsten bronze powder, 84 parts by weight of toluene, and 8 parts by weight of a dispersing agent were mixed and subjected to dispersion treatment with a bead mill to prepare a dispersion. It was about 20 nm as a result of calculating the primary particle diameter of the powder after dispersion | distribution from the result of the X-ray diffraction measurement by the Scherrer method. 10 parts by weight of this liquid and 5 parts by weight of an ultraviolet curable resin for hard coat (solid content: 100%) were mixed and applied onto a glass substrate using a bar coater. This film was dried at 60 ° C. for 30 seconds to evaporate the solvent, and then cured with light from a high-pressure mercury lamp to obtain an infrared shielding film.

The optical properties of the infrared shielding film were measured in the same manner as in Example 1. As a result, it was found that the visible light transmittance was 75.06% and the light in the visible light region was sufficiently transmitted. It was 41.85%, and it was found that about 58% of direct incident light of sunlight was shielded, and the heat insulation effect was high. Further, the haze was 0.4%, and the transparency was extremely high, and the internal situation could be clearly confirmed from the outside. The transmitted color tone was black with a faint green color. This was a good color tone close to an achromatic color.
As a result of investigating the UV resistance of this film in the same manner as in Example 1, the visible light transmittance after exposure was 73.03%, and the difference in transmittance before and after exposure was 2.03 points. It was found to have UV characteristics.

It is a schematic diagram which shows the crystal structure of the composite tungsten oxide fine particle which has a hexagonal crystal which concerns on this embodiment.

Explanation of symbols

1 WO ₆ units 2 M element

Claims (8)

Tungsten oxide fine particles represented by the general formula W _y O _z (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999), or / and the general formula M _x WO ₃ (where , M is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, and Na, W is tungsten, O is oxygen, 0.001 ≦ One or more fine particles selected from composite tungsten oxide fine particles represented by X ≦ 1),
One or more elements selected from Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb, or compounds thereof exist on the surface of the fine particles. tungsten-containing oxide fine particles, characterized in that there. The tungsten oxide fine particles include a magnesium phase having a composition ratio represented by a general formula W _y O _Z (W is tungsten, O is oxygen, 2.45 ≦ z / y ≦ 2.999). The tungsten-containing oxide fine particles according to claim 1. _{3. The} tungsten according to claim 1, wherein a crystal structure of the composite tungsten oxide fine particles represented by M _x WO _{3 includes an} amorphous structure or a cubic, tetragonal or hexagonal tungsten bronze structure. Contains fine oxide particles. The tungsten-containing oxide fine particles according to any one of claims 1 to 3,
A tungsten-containing oxide fine particle, wherein the fine particle is blue, green, or black.   An infrared shielding body comprising the tungsten-containing oxide fine particles according to any one of claims 1 to 4 dispersed in a medium.   The infrared shielding body according to claim 5, wherein the medium is a transparent resin or glass. Tungsten oxide fine particles represented by the general formula W _y O _z (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999), or / and the general formula M _x WO ₃ (where , M is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, and Na, W is tungsten, O is oxygen, 0.001 ≦ In the composite tungsten oxide fine particles represented by X ≦ 1), one or more kinds selected from Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb A tungsten-containing oxide fine particle is produced by adding an element or a compound thereof and mixing them uniformly, followed by heat treatment in a reducing gas atmosphere at 600 ° C. or lower to produce a tungsten-containing oxide fine particle. Direction . Tungsten oxide fine particles represented by the general formula W _y O _z (W is tungsten, O is oxygen, 2.2 ≦ z / y ≦ 2.999), or / and the general formula M _x WO ₃ (where , M is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Sn, Ca, Sr, and Na, W is tungsten, O is oxygen, 0.001 ≦ X ≦ 1) composite tungsten oxide fine particles, and one or more selected from Cu, Fe, Mn, Ni, Co, Pt, Au, Ag, Na, In, Sn, Cs, and Rb A method for producing tungsten-containing oxide fine particles, wherein an element or a compound thereof is vigorously mixed using a medium stirring mill to produce tungsten-containing oxide fine particles.

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