Infrared shielding film, and structure

Abstract

To provide a molecular film containing tungsten and oxygen.SOLUTION: Disclosed is a molecular film containing a tungsten-oxygen octahedral block.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a molecular film, a molecular film assembly, an infrared shielding film, and a structure.

Background Art

[0002] Patent Document 1 discloses an infrared shielding material fine particle dispersion in which infrared shielding material fine particles are dispersed in a medium, wherein the infrared shielding material fine particles contain tungsten oxide fine particles and / or composite tungsten oxide fine particles, and the particle diameter of the infrared shielding material fine particles is 1 nm or more and 800 nm or less.

[0003] Patent Document 2 discloses a laminated structure for solar radiation shielding, in which an intermediate layer containing fine particles having a solar radiation shielding function is interposed between two laminated plates selected from plate glass, plastic, and plastic containing fine particles having a solar radiation shielding function, and the fine particles having a solar radiation shielding function are composed of tungsten oxide fine particles and / or composite tungsten oxide fine particles.

[0004] Patent Document 3 discloses a transparent conductive film containing tungsten oxide and / or composite tungsten oxide, having a maximum transmittance of 10% or more and less than 92% in the wavelength range of 400 nm or more and 780 nm or less, and having a surface resistance (sheet resistance) of 1.0×10 10 Ω / □ or less.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Literature

[0006]

Non-Patent Literature 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] As disclosed in Patent Documents 1 to 3, tungsten oxides and composite tungsten oxides are known to function as infrared shielding materials, transparent conductive films, etc., and can be used for various applications.

[0008] And, for the purpose of expressing new functions and applying them to new uses, a new film-like body containing tungsten and oxygen has been demanded.

[0009] Therefore, in one aspect of the present invention, an object is to provide a molecular film containing tungsten and oxygen.

Means for Solving the Problems

[0010] In one aspect of the present invention, a molecular film containing a tungsten-oxygen octahedral block is provided.

Effects of the Invention

[0011] In one aspect of the present invention, a molecular film containing tungsten and oxygen can be provided.

Brief Description of the Drawings

[0012]

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DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention.

[0014] [Molecular film, molecular film assembly] (1) Regarding the structure (1-1) Molecular film The molecular film of this embodiment can contain tungsten-oxygen octahedron blocks. Note that the molecular film of this embodiment can also be composed only of tungsten-oxygen octahedron blocks, but even in this case, it does not exclude containing inevitable impurities mixed in during the manufacturing process or the like.

[0015] The molecular film of this embodiment and the tungsten-oxygen octahedron blocks contained in the molecular film will be described with reference to FIG. 1, which is a schematic plan view.

[0016] In FIG. 1, a crystal structure of hexagonal tungsten bronze having a plurality of tungsten-oxygen octahedron blocks 11 formed by WO6 units is shown. The tungsten-oxygen octahedron block 11 has a structure in which oxygen is arranged at the vertices of the octahedron and tungsten is arranged at the center of the octahedron. The molecular film of this embodiment can contain a plurality of tungsten-oxygen octahedron blocks 11, for example, as shown in FIG. 1, and a plurality of tungsten-oxygen octahedron blocks 11 can be arranged, for example, in a planar shape or in a linear shape.

[0017] The molecular film of this embodiment can also have a structure based on, for example, a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton.

[0018] As described later, the molecular film of the present embodiment can also contain a composite tungsten oxide. In this case, the composite tungsten oxide has, for example, a structure in which six of the above-described tungsten-oxygen octahedron blocks 11 are assembled to form a hexagonal void 12, and M13 contained in the composite tungsten oxide is arranged in the void 12 to form one unit, and a large number of these units are assembled.

[0019] For example, FIG. 2(B) shows an example of the structure of the molecular film obtained from Cs4W shown in FIG. 2(A). 11 O 35 FIG. 2(B) corresponds to the structure of the molecular film obtained in Examples 3, 4, 7, and 8 described later, for example.

[0020] Further, FIG. 3(B) shows an example of the structure of the molecular film obtained from Rb4W shown in FIG. 3(A). 11 O 35 FIG. 3(B) corresponds to the structure of the molecular film obtained in Example 5 described later, for example. FIGS. 2(B) and 3(B) have a structure in which M13 is arranged in the hexagonal void 12 as described above. In the case of FIG. 2(B), M13 is Cs, and in the case of FIG. 3(B), M13 is Rb.

[0021] On the other hand, for example, FIG. 4(B) shows an example of the structure of the molecular film obtained from Cs6W shown in FIG. 4(A). 11 O 36 FIG. 4(B) corresponds to the structure of the molecular film obtained in Examples 1 and 2 described later. The structure of the molecular film shown in FIG. 4(B) has a pyrochlore structure similar to CsW2O6, for example. Note that the molecular film obtained from Cs 8.5 W 15 O 48 also has a similar structure. Locally, these have a structure in which M13 is arranged in the hexagonal void formed by the tungsten-oxygen octahedron block 11, but the hexagon and M are stacked in the direction perpendicular to the bc plane while shifting in the c-axis direction of FIG. 4(B).

[0022] In addition, the molecular film of this embodiment can also contain tungsten oxide. In this case, the tungsten oxide can be formed by the above tungsten-oxygen octahedral blocks or the like. As a corresponding structure, for example, FIG. 5(B) shows an example of the structure of the molecular film obtained from Bi2W2O9 shown in FIG. 5(A). FIG. 5(B) corresponds to the structure of the molecular film obtained in Example 6 described later, for example.

[0023] By including tungsten-oxygen octahedral blocks, the molecular film of this embodiment can be made into a molecular film with excellent infrared shielding performance by infrared reflection. Further, by introducing oxygen deficiency into the tungsten-oxygen octahedral blocks, a molecular film with even more excellent infrared shielding performance by infrared reflection can be made.

[0024] Materials containing free electrons can exhibit a reflection absorption response to electromagnetic waves in the region around sunlight with wavelengths from 200 nm to 2600 nm due to plasma oscillation. And since the molecular film of this embodiment is a sheet-shaped conductive material, that is, a material containing free electrons, among the reflection absorption responses to electromagnetic waves such as infrared rays shown by the above plasma oscillation, the reflection response becomes more prominent than the absorption response. For this reason, the molecular film of this embodiment can exhibit the infrared shielding performance by infrared reflection as described above.

[0025] In addition, since the molecular film of this embodiment has a sheet shape, for example, even if the film thickness is thin, it can exhibit high infrared shielding performance. Furthermore, compared with the case of using infrared shielding material fine particles disclosed in Patent Documents 1, 2, etc., light scattering of visible light can be reduced and visible light transparency can be improved.

[0026] Note that as long as the molecular film of this embodiment contains the above tungsten-oxygen octahedral blocks, it can exhibit the above-described infrared shielding performance, and thus it may be crystalline or non-crystalline.

[0027] As will be described later, for example, the molecular film of the present embodiment can be produced by using a composite tungsten oxide having a layered crystal structure as a raw material and exfoliating it to a single layer, which is the basic minimum unit of the crystal structure, by means of soft chemical treatment. The molecular film of the present embodiment can have a sheet shape with a thickness of about 1 nm or more and 10 nm or less (corresponding to several to several tens of atoms). Depending on the conditions of the soft chemical treatment, the molecular film of the present embodiment can also be exfoliated into two or three layers and used for manufacturing.

[0028] As will be described later, a plurality of the molecular films of the present embodiment can be integrated to form a molecular film assembly. The molecular films contained in the molecular film assembly of the present embodiment may be expected to have infrared shielding performance as long as the length in the longitudinal direction is long and the anisotropy with respect to the thickness is large.

[0029] By adjusting the synthesis (firing) temperature of the composite tungsten oxide having a layered crystal structure before exfoliation by soft chemical treatment, or by using a single crystal of the composite tungsten oxide or tungsten oxide, the length in the longitudinal direction of the molecular film can be controlled. For example, it is possible to synthesize a molecular film with the length in the longitudinal direction adjusted in the range of 20 nm or more and 1 mm or less. Even for molecular films with various lengths in the longitudinal direction like this, in order to exhibit excellent infrared shielding performance, the molecular film assembly of the present embodiment containing the molecular film can be applied as, for example, a general-purpose window material.

[0030] The molecular film is flexible and may have a bent sheet shape in a liquid or the like. Since its flexibility is maintained even in a solid, for example, the molecular film can be bent together with a flexible substrate, and even when bent, the structure such as the atomic arrangement in the molecular film is maintained without being destroyed.

[0031] From the viewpoint of ensuring visible light transparency, the thickness of the molecular film is preferably 200 nm or less, more preferably 100 nm or less, still more preferably 50 nm or less, and even more preferably 10 nm or less.

[0032] (1-2) Molecular film assembly A plurality of the molecular films of the present embodiment can be integrated to form a molecular film assembly. That is, the molecular film assembly can contain a plurality of molecular films.

[0033] The molecular film assembly of the present embodiment can be composed only of molecular films, or can be composed of a laminate of molecular films or the like. Also, the molecular films may be in contact with each other or may be separated. That is, for convenience, the term "integration" is used, but it is not necessarily required to bring the molecular films into contact with each other. The molecular film assembly of the present embodiment can be configured by spreading the molecular film on a smooth substrate as shown in the AFM images of FIGS. 6(A) and 7(A), or can be configured by combining lamination and spreading. The molecular film assembly of the present embodiment can also be configured by combining a molecular film and infrared shielding material particles, among other things.

[0034] An AFM image of a molecular film assembly in which the molecular films of the present embodiment are spread on a large number of substrates is shown in FIG. 6(A). The molecular film assembly of the present embodiment can be made into a molecular film assembly excellent in infrared shielding performance by infrared reflection, for example, by spreading and arranging the molecular film 61A and the molecular film 61B on the same plane as shown in FIG. 6(A). Also, the molecular film assembly of the present embodiment can have a gap 62 between the adjacent molecular film 61A and the molecular film 61B as shown in FIG. 6(A), and radio waves can be transmitted through the gap, for example.

[0035] Here, FIG. 6(B) shows the cross-sectional profile of the X1-Y1 line portion of FIG. 6(A). As shown in FIG. 6(B), it was confirmed that the portion of the gap 62 between the molecular film 61A and the molecular film 61B is lower than other portions. That is, it was also confirmed from the measurement results of the AFM height that the molecular film assembly of the present embodiment has a gap between the molecular films.

[0036] In addition, FIG. 7(A) shows an AFM image when observed after passing through a heat treatment process described later from the molecular film assembly shown in FIG. 6(A). Similar to before the heat treatment, a plurality of molecular films are laid out and arranged on the same plane to form a molecular film assembly. Further, FIG. 7(B) shows a cross-sectional profile of the X2 - Y2 line portion of FIG. 7(A). It was confirmed that there is a gap between the molecular films because the portion of the gap 72 between the molecular film 71A and the molecular film 71B is lower than other portions.

[0037] Since the molecular film assembly of the present embodiment has a gap between the molecular films as described above, for example, the sheet resistance can be set to 10 7 Ω / □ or more, and a film excellent in radio wave permeability can be obtained. That is, the molecular film assembly of the present embodiment can have excellent performance in both infrared shielding performance and radio wave permeability.

[0038] The molecular film assembly of the present embodiment can be manufactured, for example, by laminating or laying out molecular films on a smooth substrate. Further, the molecular film assembly of the present embodiment can also be obtained by laminating or laying out molecular films on a smooth substrate and then performing heat treatment. At this time, from the viewpoint of introducing oxygen deficiency into the tungsten - oxygen octahedron block of the molecular film and exhibiting an excellent infrared shielding function, it is preferable to perform heat treatment in an inert gas atmosphere, a vacuum atmosphere, or a reducing atmosphere. Also, although the gap between the molecular films may disappear by heat treatment at a high temperature, it is also possible to retain radio wave permeability by partially leaving a region with low conductivity at the interface etc. of the molecular film.

[0039] The molecular film included in the molecular film assembly of the present embodiment preferably contains a tungsten - oxygen octahedron block as described above and has the repeating structure of the block as a basic skeleton. That is, it is preferably crystalline. That the repeating structure of the tungsten - oxygen octahedron block is used as the basic skeleton can be confirmed by analyzing an electron diffraction pattern measured by a transmission electron microscope or by analyzing an XRD pattern measured by an X - ray diffraction (XRD) apparatus.

[0040] When measuring the structure of the molecular film or molecular film assembly of the present embodiment using an X-ray diffractometer, since the molecular film or molecular film assembly may be in the form of a sheet with a thickness of about 1 nm or more and 10 nm or less, it is necessary to measure the XRD pattern by the thin film X-ray diffraction method rather than the powder X-ray diffraction method. In the thin film X-ray diffraction method, since the incident angle of X-rays is fixed at a small angle of 0.5° or less near the total reflection critical angle for measurement, the penetration depth of X-rays into the sample is several tens of nm, and the signal of the diffracted X-rays can be detected with high precision with almost no influence from the substrate. There are methods such as grazing incidence X-ray diffraction (GI-XRD) and in-plane X-ray diffraction in the thin film X-ray diffraction method, but among them, it is preferable to use the in-plane X-ray diffraction method. In-plane X-ray diffraction is also called the φ-2θχ scan method, etc. Since the goniometer is scanned horizontally within the sample plane, it is important to accurately adjust the inclination and rocking axis within the plane of the sample. As a result, the angle of the incident X-rays can be controlled to 0.2° or less, and the crystal state of an ultrathin film with a film thickness of several nm or less and the orientation state of the crystal plane in the direction perpendicular to the substrate surface can be measured. Examples of devices that can be measured by the in-plane X-ray diffraction method include the Rigaku fully automatic multi-purpose X-ray diffractometer SmartLab, etc. (2) Regarding the composition

[0041] The molecular film of the present embodiment contains a tungsten-oxygen octahedron block, and it is desirable to introduce oxygen deficiency from the viewpoint of enhancing the infrared shielding performance. Further, it preferably contains one or more selected from composite tungsten oxides and tungsten oxides.

[0042] Hereinafter, the composite tungsten oxides and tungsten oxides that can be preferably contained in the molecular film of the present embodiment will be described.

[0043] (Composite tungsten oxide) Generally, materials containing free electrons are known to exhibit a reflection absorption response to electromagnetic waves in the region of sunlight with wavelengths from 200 nm to 2600 nm due to plasma oscillations. When the powder of such a material is made into particles smaller than the wavelength of light, it is known that geometric scattering in the visible light region (wavelengths from 380 nm to 780 nm) is reduced, and transparency in the visible light region is obtained. In this specification, "transparency" is used to mean "low scattering and high transmittance for light in the visible light region".

[0044] Since there are no effective free electrons in tungsten oxide (WO3), it has little absorption and reflection characteristics in the infrared region and is not effective as an infrared absorption material or an infrared reflection material.

[0045] On the other hand, WO with oxygen deficiency 3-δ and composite tungsten oxides obtained by adding positive elements such as Na to WO3 are known to be conductive materials and materials having free electrons. And through the analysis of single crystals and the like of these materials having free electrons, the response of free electrons to light in the infrared region is suggested.

[0046] By adding M, which is an element or atomic group (molecule) described later, to the above-mentioned WO3 to form a composite tungsten oxide, free electrons are generated in the WO3, and particularly strong absorption and reflection characteristics derived from free electrons are exhibited in the near-infrared region, making it effective as a near-infrared absorption material or a near-infrared reflection material around a wavelength of 1000 nm. Furthermore, by introducing oxygen deficiency, stronger absorption and reflection characteristics are exhibited.

[0047] That is, by using both control of the oxygen amount and addition of M that generates free electrons to the WO3, excellent infrared absorption materials and infrared reflection materials can be obtained. Therefore, it is preferable that the molecular film of this embodiment contains the above composite tungsten oxide. The general formula of the composite tungsten oxide using both control of the oxygen amount and addition of M that generates free electrons is M x W y O zWhen described as above, it is preferable that x, y, and z satisfy the relationship of 0.001 ≦ x / y ≦ 1 and 2.0 ≦ z / y ≦ 3.5. However, M in the above general formula can be one or more selected from the group of elements and the group of atomic groups. As the above group of elements, H, B, C, N, F, alkali metal elements, alkaline earth metal elements, rare earth elements, Be, 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, P, S, Se, Cl, Br, I, Te, Ti, Nb, V, Mo, Ta, Re, Hf, Os, Bi can be mentioned. As the above group of atomic groups, Bi2O2, OH, H2O, H3O can be mentioned. Further, W in the above general formula represents tungsten, and O represents oxygen. The molecular film of the present embodiment can also contain a composite tungsten oxide as described above. In this case, it is preferable that the composite tungsten oxide contained in the molecular film satisfies the above general formula.

[0048] First, the value of x / y indicating the addition amount of M will be described.

[0049] If the value of x / y is 0.001 or more, a sufficient amount of free electrons is generated in the composite tungsten oxide, and the desired infrared absorption effect and infrared reflection effect can be obtained. And the larger the addition amount of M, the more the supply amount of free electrons increases, and the infrared absorption efficiency and infrared reflection efficiency also increase. However, the effect also saturates when the value of x / y is about 1. Further, if the value of x / y is 1 or less, it is preferable because the generation of impurity phases can be suppressed.

[0050] Next, the value of z / y indicating the control of the oxygen amount will be described. General formula W y O z In the case of tungsten oxide represented by, free electrons can be generated by oxygen deficiency by making z / y smaller than 3. For this reason, in the case of tungsten oxide, near-infrared absorption ability and near-infrared reflection ability can be exhibited by making z / y less than 3.

[0051] On the other hand, general formula M x W y Oz In the composite tungsten oxide represented by the above formula, in addition to the same mechanism as that of the tungsten oxide represented by the general formula W y O z working, there is also the supply of free electrons due to the addition amount of M as described above when 3 ≤ z / y ≤ 3.5. In addition, in the molecular film, since its surface may be negatively charged, z / y may show a reflection absorption response due to the supply of free electrons even when it is 3.5. However, the crystal phase of WO2 may cause absorption and scattering of light in the visible light region and reduce the absorption and reflection of light in the near-infrared region. Therefore, from the viewpoint of suppressing the generation of WO2, it is preferable that z / y is 2.0 or more. From the above, 2.0 ≤ z / y ≤ 3.5 is preferable, more preferably 2.2 ≤ z / y ≤ 3.3, and still more preferably 2.45 ≤ z / y ≤ 3.3.

[0052] M is preferably at least one selected from the group consisting of H, B, C, N, F, alkali metal elements, alkaline earth metal elements, rare earth elements, Be, 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, P, S, Se, Cl, Br, I, Te, Ti, Nb, V, Mo, Ta, Re, Hf, Os, Bi, and the atomic group consisting of Bi2O2, OH, H2O, and H3O.

[0053] Here, from the viewpoint of the stability of M added to the M x W y O z it is more preferable that M is at least one selected from the group consisting of H, alkali metal elements, alkaline earth metal elements, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, and the atomic group consisting of Bi2O2, H2O, and H3O.

[0054] M more preferably contains one or more selected from H, an alkali metal, Ca, Sr, Ba, Fe, Cu, Ag, In, Tl, Sn, Pb, and Yb.

[0055] From the viewpoint of improving the optical properties and weather resistance as an infrared absorption material or an infrared reflection material, M preferably belongs to any one of an alkali metal element, an alkaline earth metal element, a transition metal element, a Group 4B element, and a Group 5B element.

[0056] The crystal structure of the composite tungsten oxide is not particularly limited, and for example, it can have one or more structures selected from a hexagonal crystal, a cubic crystal, a tetragonal crystal, etc. The composite tungsten oxide may be amorphous.

[0057] The composite tungsten oxide can have, for example, the atomic arrangement shown in FIG. 1 in the molecular film of the present embodiment.

[0058] As described above, six tungsten-oxygen octahedron blocks 11 aggregate to form a hexagonal void 12, and M13 contained in the composite tungsten oxide is arranged in the void 12 to form one unit, and a large number of these units can aggregate. Such a unit structure may be regularly arranged or randomly arranged in the molecular film of the present embodiment. By including such a structure in the molecular film of the present embodiment, the transmission of light in the visible light region is particularly improved, and the reflection absorption response of light in the infrared region is particularly improved.

[0059] When M is added and present in the hexagonal voids, the light transmission in the visible light region is particularly improved, and the light absorption and reflection in the infrared region are particularly improved. Generally, when M with a large ionic radius or molecular size (atomic group size) is added, the unit structure shown in FIG. 1 is likely to be formed. Specifically, when M contains one or more selected from the group of elements consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn, the unit structure shown in FIG. 1 is likely to be formed. Therefore, the composite tungstate preferably contains one or more elements selected from the group of elements consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn as M. Note that M can also be composed of one or more selected from the above group of elements.

[0060] Furthermore, among these elements M with a large ionic radius, in a composite tungstate containing one or more selected from Cs and Rb, the unit structure shown in FIG. 1 is likely to be formed, achieving both light absorption and reflection in the infrared region and light transmission in the visible light region, and particularly high performance can be exhibited. Therefore, it is more preferable that M contains one or more selected from Cs and Rb. Note that M can also be composed of one or more selected from Cs and Rb.

[0061] Of course, even when M contains elements or atomic groups other than the above, it is only necessary that M is present in the hexagonal voids formed by WO6 units, and it is not limited to the above-mentioned elements.

[0062] When the composite tungstate having the above structure has a uniform crystal structure, the addition amount of M is preferably 0.001 ≦ x / y ≦ 1, and more preferably 0.2 ≦ x / y ≦ 0.6 in terms of the value of x / y.

[0063] (Tungstate)

[0064] The molecular film of this embodiment can also contain tungstate. Tungstate has the general formula W y O z(However, W is tungsten, O is oxygen, and 2.0 ≦ z / y < 3.5). The general formula is W y O z In the tungsten oxide represented by the formula, the composition range of the tungsten and oxygen is preferably such that the composition ratio (z / y) of oxygen to tungsten is less than 3.5, more preferably 2.0 ≦ z / y < 3.5, and even more preferably 2.2 ≦ z / y < 3.5. Particularly preferably, 2.45 ≦ z / y ≦ 3.499.

[0065] If the value of z / y is 2.0 or more, it is possible to avoid the appearance of an unwanted WO2 phase in the tungsten oxide and enhance the chemical stability as a material, so it becomes a particularly effective infrared absorption material. Further, by setting the value of z / y to preferably less than 3.5, more preferably 3.499 or less, a sufficient amount of free electrons are generated due to oxygen deficiency to enhance the absorption and reflection characteristics in the infrared region, and an efficient infrared absorption material or infrared reflection material can be obtained. Here, in the molecular film, its surface may be negatively charged, so z / y may exceed 3. However, when z / y = 3.5, the molecular film of tungsten oxide has no oxygen deficiency, and a sufficient amount of free electrons are not generated, and the intended infrared absorption effect or infrared reflection effect may not be obtained sufficiently.

[0066] Furthermore, the so-called "Magnéli phase" having a composition ratio represented by 2.45 ≦ z / y ≦ 3.499 (also considering the case where the molecular film surface is negatively charged) is chemically stable and has excellent absorption and reflection characteristics of light in the near-infrared region, so it can be more preferably used as an infrared absorption material. For this reason, the value of z / y is more preferably 2.45 ≦ z / y ≦ 3.499 as described above. (3) Regarding the characteristics of the molecular film and the molecular film assembly In addition to the infrared shielding function, the molecular film of the present embodiment can also have chromic properties. Tungsten oxide and composite tungsten oxides are photochromic materials like other hydrated tungsten oxides and are known as electrochromic materials. The molecular film of the present embodiment is also a photochromic material and an electrochromic material. The molecular film of the present embodiment exhibits a photochromic reaction in response to light such as high-energy ultraviolet rays and visible light. Also, when the threshold energy required for the reaction is low, it exhibits a photochromic reaction in response to infrared rays as well. Due to the response to ultraviolet rays, visible light, etc., cationic species such as protons generated around the molecular film are adsorbed onto the molecular film, creating a light absorption / reflection region. Therefore, in a photochromic material, it is important to increase the surface area so that more cationic species can be adsorbed. Also, it is important to enhance the crystallinity so that the generation of the light absorption region due to the adsorption of cationic species can be further increased. Note that examples of the proton supply source due to the response to ultraviolet rays, visible light, etc. include organic substances, such as additives like bulky guests typified by quaternary ammonium ions used in the soft chemical treatment described later, and resins used as the matrix of the structure.

[0067] As described above, by including a tungsten-oxygen octahedron block, the molecular film of the present embodiment can be made into a molecular film with excellent infrared shielding performance by infrared reflection. Also, by introducing oxygen deficiency, it can be made into a molecular film with even higher infrared shielding performance. That is, the molecular film of the present embodiment can be used as an infrared shielding material.

[0068] Also, the molecular film assembly of the present embodiment can contain the aforementioned molecular film. Therefore, the molecular film assembly of the present embodiment can also be used as an infrared shielding material.

[0069] [Manufacturing Method of Molecular Film] Next, the manufacturing method of the molecular film of the present embodiment will be described. According to the manufacturing method of the molecular film of the present embodiment, since the aforementioned molecular film can be manufactured, the description of matters already explained will be omitted.

[0070] In the method for producing a molecular film according to this embodiment, for example, a composite tungstate having a layered crystal structure can be used as a raw material. By subjecting a raw material having a layered crystal structure to a soft chemical treatment, it can be exfoliated into one or more layers, which are the basic minimum units of the crystal structure, to obtain a molecular film. Further, by subjecting it to a reduction treatment, a molecular film excellent in infrared shielding function can be obtained.

[0071] The soft chemical treatment is a treatment combining an acid treatment and a colloidization treatment. That is, when an acid aqueous solution such as hydrochloric acid is brought into contact with a composite tungstate powder or the like having a layered crystal structure, and the product is filtered, washed, and then dried, part or all of the alkali metal ions or the like present between the layers before the acid treatment are exchanged with hydrogen ions, and a hydrogen-type substance is obtained. Next, when the obtained hydrogen-type substance is put into an aqueous solution such as an amine and stirred, it is colloidalized. At this time, the layers constituting the layered crystal structure are exfoliated one by one. The layers constituting the layered crystal structure specifically mean, for example, those having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton.

[0072] Therefore, the method for producing a molecular film according to this embodiment can include the following acid treatment step and colloidization step.

[0073] In the acid treatment step, a raw material having a layered crystal structure is brought into contact with an acid aqueous solution, and the product is washed and dried to obtain a hydrogen-type substance.

[0074] In the colloidization step, a hydrogen-type substance and a liquid containing a bulky guest are mixed to obtain a molecular film.

[0075] As the raw material having a layered crystal structure as the raw material, for example, a composite tungstate can be used. The raw material is Rb4W 11 O 35 、Cs4W 11 O 35 、Cs 6+A W 11 O 36(0 ≦ A ≦ 0.31), Cs 8+B W 15 O 48 (0 ≦ B ≦ 0.5), preferably containing one or more composite tungsten oxides selected from (Bi2O2)W2O7. These composite tungsten oxides have alkali metal ions such as Rb and Cs and cations such as Bi2O2 present between the layers.

[0076] In the soft chemical treatment, for example, an acid aqueous solution is brought into contact with a composite tungsten oxide powder having a layered crystal structure to obtain a hydrogen-type substance. Specifically, for example, Rb 4-a H a W 11 O 35 (0 ≦ a ≦ 4), Cs 4-b H b W 11 O 35 (0 ≦ b ≦ 4), Cs 6+A-c H c W 11 O 36 (0 ≦ c ≦ 6.31), Cs 8+B-d H d W 15 O 48 (0 ≦ d ≦ 8.5), (Bi2O2) 1-e H 2e W2O7(0 ≦ e ≦ 1) hydrogen-type substances are obtained. These hydrogen-type substances are those in which some or all of the alkali metal ions and cations present between the layers before the acid treatment have been exchanged with hydrogen ions. The hydrogen-type substances are hydrated in an aqueous solution and retain the hydrate even after filtration, washing, and drying or air-drying at room temperature. Also, a substance in which hydrogen H is replaced with oxonium can be obtained.

[0077] The acid aqueous solution used for the acid treatment is not particularly limited as long as it does not dissolve the composite tungsten oxide, and hydrochloric acid, nitric acid, sulfuric acid, carbonic acid, etc. can be used. The ion exchange amount can be changed by the type, concentration, and number of treatments of the acid.

[0078] Next, for example, by inserting a bulky guest between the layers of a hydrogenated substance which is an acid-treated product, the hydrogenated substance can be exfoliated down to a single layer which is the basic minimum unit of the crystal structure, and a sheet-shaped molecular film can be obtained. Specifically, for example, Rb 4-a W 11 O 35 a- (0 ≦ a ≦ 4), Cs 4-b W 11 O 35 b- (0 ≦ b ≦ 4), Cs 6+A-c W 11 O 36 c- (0 ≦ c ≦ 6.31), Cs 8+B-d W 15 O 48 d- (0 ≦ d ≦ 8.5), (Bi2O2) 1-e W2O7 e- (0 ≦ e ≦ 1) molecular films can be obtained. Here, when the molecular film is precisely separated, all are obtained in a negatively charged state. However, since the bulky guest modifies the surface of the molecular film as a cation, it is considered that the whole including the bulky guest is in a state close to neutrality.

[0079] Bulky guests typified by quaternary ammonium ions are used by bringing them into contact with the hydrogenated substance in a liquid such as water or an organic solvent. For example, a material that supplies a bulky guest typified by a quaternary ammonium salt is dissolved in an appropriate liquid, the hydrogenated substance is added thereto, and the liquid is mixed and shaken to exfoliate the hydrogenated substance down to a single layer.

[0080] As the ions serving as the bulky guest, one or more quaternary ammonium ions selected from tetrabutylammonium ions, tetrapropylammonium ions, tetraethylammonium ions, tetramethylammonium ions, etc. can be preferably used. However, tetrabutylammonium ions (hereinafter, "TBA" +(also referred to as "」).) can be particularly preferably used. Further, as a material for supplying a bulky guest, the above quaternary ammonium salt can be preferably used, and tetrabutylammonium hydroxide can be particularly preferably used.

[0081] For example, consider the case of using a composite tungsten oxide having a layered crystal structure as a raw material, such as Rb4W 11 O 35 As shown in Fig. 3(A), Rb4W 11 O 35 has a layered crystal structure in which a layer 31 in which a six-membered ring structure is arranged as a repeating structure of tungsten-oxygen octahedron blocks and a plane 32 in which only Rb exists are alternately laminated. That is, it has a structure in which alkali metal Rb exists between the layers of layer 31. Note that the six-membered ring structure of the octahedron block is a hexagonal tungsten bronze structure, and a one-dimensional tunnel of Rb exists in the six-membered ring structure. When the acid treatment is performed on Rb4W 11 O 35 having this layered crystal structure, part or all of Rb existing on the plane 32 is extracted as ions into the acid aqueous solution, and hydrogen ions or oxonium ions are introduced into the voids to obtain a hydrogen-type substance. At this time, depending on the acid treatment conditions, Rb existing in the one-dimensional tunnel in the six-membered ring structure of layer 31 may also be extracted during the acid treatment. Next, the hydrogen-type substance is added to a liquid containing a quaternary ammonium ion or the like that functions as a bulky guest, and the liquid is mixed and shaken. Thus, while maintaining the six-membered ring structure of layer 31 and the one-dimensional tunnel of Rb, the hydrogen-type substance can be peeled off to a single layer, and a molecular film of layer 31 can be obtained. At this time, since the quaternary ammonium that functions as a bulky guest acts as a surface modifier and a dispersant of the molecular film, the molecular film is obtained in a dispersed state in the liquid, that is, a dispersion liquid containing the molecular film is obtained. The dispersion liquid can be used as a first coating liquid, for example, in the first coating step when manufacturing an infrared shielding film described later.

[0082] Depending on the acid treatment conditions such as the type, concentration, and number of treatments of the acid, for example, the general formula Rb 4-a H a W11 O 35 (0 ≦ a ≦ 4), the amount of a in the hydrogen-type substance represented by this, that is, the ion exchange amount, can be changed. For example, when all of the Rb present on surface 32 is ion-exchanged, a = 1 and Rb3HW 11 O 35 of the hydrogen-type substance is obtained, and Rb3W 11 O 35 - of the molecular film is obtained. In addition, when all of the Rb present in the one-dimensional tunnel within the six-membered ring structure of layer 31 is also ion-exchanged, H4W 11 O 35 of the hydrogen-type substance is obtained, and W 11 O 35 of the molecular film is obtained. Note that for both molecular films of Rb3W 11 O 35 - and W 11 O 35 4- their surfaces are negatively charged. Usually, since the maximum valence of W is 6+, the molecular films are in charge states of -1 and -4 respectively. However, since a bulky guest modifies the molecular film surface as a cation at the same time as the molecular film is obtained, it is considered that the whole including the bulky guest is in a state close to neutrality.

[0083] Here, from the viewpoint of allowing the reaction of peeling the hydrogen-type substance after acid treatment to a single layer to proceed sufficiently, it is preferable to perform ion exchange with a ≥ 1, which corresponds to the amount of ions of Rb present on surface 32, that is, the amount of ions of Rb present between the layers of layer 31. Therefore, it is preferable to perform acid treatment so that a ≥ 1 in the above general formula, and it is preferable to perform acid treatment at a solid / liquid ratio of hydrochloric acid, nitric acid, sulfuric acid, or carbonic acid with a concentration of 6 N or more of (solid) / (aqueous solution) = 1 g / 100 cm -3 or less. However, this is the preferable acid treatment condition when using Rb4W 11 O 35 as a raw material, and the preferable conditions change depending on the raw material used.

[0084] The addition amount of the bulky guest is not particularly limited. For example, Rb 4-a H a W 11 O35 TBA, which is an ion that becomes a bulky guest with respect to the amount of hydrogen ions of the hydrogen-type substance represented by (0 ≦ a ≦ 4) + is preferably added so that the molar ratio thereof is in the range of 0.5 or more and 2 or less. By setting the molar ratio to 0.5 or more, delamination between layers can proceed particularly sufficiently. Also, by setting the molar ratio to 2 or less, it is possible to prevent the crystal structures of the hydrogen-type substance and the molecular film from collapsing. More preferably, the molecular film can be obtained with the best yield when the molar ratio is about 1.

[0085] The size of the obtained molecular film is not particularly limited, but it can have the thickness of a single layer of layer 31, and can have a thickness of, for example, 2 nm or more and 3 nm or less. Also, the length (n) in the longitudinal direction of the obtained molecular film can be, for example, 20 nm or more and 1 mm or less. That is, the aspect ratio can be, for example, 7 or more and 500000 or less. This can be controlled by adjusting the synthesis (firing) temperature of the layered composite tungsten oxide having a crystal structure as a raw material, or by using a single crystal of the composite tungsten oxide or tungsten oxide. Also, the molecular film can be destroyed by stirring or ultrasonic irradiation of the dispersion containing the obtained molecular film. For example, by applying gentle stirring, it can be controlled to a length with a width of 1 μm or more, and by applying a strong shearing force such as ultrasonic irradiation, it can be controlled to a length with a width of 1 μm or less. However, it is difficult at present to synthesize a huge molecular film having a length of 1 mm or more.

[0086] Note that unreacted substances generated in the above reaction can be removed by further centrifuging the dispersion containing the obtained molecular film.

[0087] The molecular film of this embodiment can also enhance its infrared shielding function by introducing oxygen deficiency through reduction treatment. The method of reduction treatment is not particularly limited. For example, a wet method in which an appropriate reducing agent is added simultaneously with the peeling of the aforementioned hydrogen-type substance, or an appropriate reducing agent is added after obtaining a dispersion containing the molecular film, or a dry method in which heat treatment is performed in a reducing gas can be mentioned. It is also possible to use both the wet method and the dry method in combination. When using a substrate, after spreading a large number of molecular films on the substrate, it is desirable to complete the reduction treatment as the aforementioned molecular film assembly. Further, by adding an appropriate reducing agent when obtaining the structure described later, the reduction treatment can also be completed as the structure. [Infrared shielding film] The infrared shielding film of this embodiment can include a molecular film assembly, specifically, a molecular film assembly containing the aforementioned molecular film. The infrared shielding film can be composed of only the molecular film assembly alone, only the molecular film alone, only the laminated structure described later, etc., and can exhibit infrared shielding performance even in a free-standing state without a substrate and locally supported.

[0088] Further, the infrared shielding film of this embodiment can also include a substrate and a molecular film assembly disposed on the substrate.

[0089] As an example of the case where the infrared shielding film of this embodiment has a substrate, a schematic cross-sectional view of a plane perpendicular to the substrate is shown in FIG. 8. As shown in FIG. 8, the infrared shielding film 80, which is an example of this embodiment, can have, for example, a substrate 81 and a molecular film assembly 82 disposed on at least one surface 81A of the substrate 81. Note that the molecular film assembly 82 can contain a molecular film and can have a film shape.

[0090] FIG. 8 shows an example in which the molecular film laminate 82 is provided only on one surface 81A of the base material 81, but the molecular film laminate can also be arranged on the other surface 81B of the base material 81. The molecular film laminate provided on one surface 81A and the molecular film laminate provided on the other surface 81B may be different, and either one of them may be composed of a high refractive index material described later. Further, as shown in FIG. 9, the infrared shielding film may have a laminated structure of the molecular film laminate 82 and the high refractive index material 83, but the laminated structure will be described in detail later.

[0091] Also, like the infrared shielding film 100 shown in FIG. 10, it can also have the molecular film laminate 82 and infrared shielding material particles 101 other than the molecular film. In the infrared shielding film 100, the molecular film laminate 82 and the infrared shielding material particles 101 are combined to form one layer. Note that the infrared shielding film 100 including the composite layer of the molecular film laminate 82 and the infrared shielding material particles 101 may also have the base material 81 as shown in FIG. 10, or may have a configuration without the base material 81.

[0092] Furthermore, like the infrared shielding film 110 shown in FIG. 11, the infrared shielding film may have a laminated structure of the molecular film laminate 82 containing the infrared shielding material particles 101 and the high refractive index material 83. Also in this case, the infrared shielding film may have a base material or may have a configuration without a base material. In addition, as shown in FIGS. 12 to 14, the infrared shielding film can also have a matrix, but the matrix will be described in detail later.

[0093] Hereinafter, the infrared shielding film of the present embodiment will be described for each of (1) the case where the infrared shielding film has a base material and (2) the case where the infrared shielding film has a laminated structure. (1) When the infrared shielding film has a base material

[0094] The base material 81 may be any base material that can support the molecular film laminate, and the material and its shape are not particularly limited. Since the infrared shielding film is often used for window materials, films for greenhouses, etc., the infrared shielding film preferably has any one of a sheet shape, a board shape, and a film shape. For this reason, the base material 81 also preferably has any one of a sheet shape, a board shape, and a film shape.

[0095] The material of the base material 81 is not particularly limited and can be selected according to the wavelength range of light that the infrared shielding film is required to transmit, absorb, and reflect, and the strength, thickness, etc. required for the infrared shielding film.

[0096] The base material 81 can include one or more selected from single crystal materials, polycrystalline materials, glass, metals, alloys, ceramics, and resins. The base material 81 can also be composed of any of the above materials, and can be any one of a single crystal material base, a polycrystalline material base, a glass base, a metal base, an alloy base, a ceramic base, and a resin base. Further, the base material 81 may be provided with a coating on the surface as necessary.

[0097] When the base material 81 includes a single crystal material, the single crystal material is not particularly limited, but it can be a silicon substrate, a silicon substrate with an oxide film, a silver substrate, an aluminum substrate, a gold substrate, a bismuth substrate, a cadmium substrate, a cobalt substrate, a chromium substrate, a copper substrate, a dysprosium substrate, an erbium substrate, an iron substrate, a germanium substrate, a gadolinium substrate, a hafnium substrate, a holmium substrate, an indium substrate, an iridium substrate, a lithium substrate, a magnesium substrate, a molybdenum substrate, a niobium substrate, a nickel substrate, a nickel-aluminum substrate, a lead substrate, a palladium substrate, a platinum substrate, a rhenium substrate, a rhodium substrate, a ruthenium substrate, an antimony substrate, a tin substrate, a tantalum substrate, a terbium substrate, a tellurium substrate, a titanium substrate, a vanadium substrate, a tungsten substrate, a yttrium substrate, a zinc substrate, a zirconium substrate, an alloy crystal substrate, a silicon carbide substrate, a gallium nitride substrate, a gallium phosphide substrate, an indium phosphide substrate, a lithium fluoride substrate, a lanthanum fluoride substrate, a magnesium fluoride substrate, a strontium fluoride substrate, a potassium bromide substrate, a potassium chloride substrate, a sodium chloride substrate, a mica substrate, an aluminum oxide substrate, a titanium oxide substrate, a cobalt oxide substrate, a chromium oxide substrate, a manganese oxide substrate, a nickel oxide substrate, a tin oxide substrate, a zinc oxide substrate, a copper oxide substrate, an iron oxide substrate, a strontium titanate substrate, a lithium niobate substrate, a lithium tantalate substrate, a potassium tantalate substrate, a yttrium aluminate substrate, a lanthanum aluminate substrate, a lanthanum strontium aluminate substrate, a strontium gallium lanthanum substrate, a dysprosium scandate substrate, a gadolinium scandate substrate, a neodymium scandate substrate, a gadolinium gallium garnet substrate, a yttrium aluminum garnet substrate, and one or more selected therefrom.

[0098] When the base material 81 includes a polycrystalline material, a substrate of the same material as the above-described single crystal material can be preferably used, except that the constituent material is polycrystalline.

[0099] When the substrate 81 contains glass, the glass material is not particularly limited, but it is preferably at least one selected from various functional glasses such as fused quartz glass, synthetic quartz glass, soda-lime glass, borosilicate glass, crystal glass, alkali-free glass, lead glass, uranium glass, tempered glass, heat-resistant glass, heat-ray absorbing glass, and Low-E glass.

[0100] When the substrate 81 contains metal, its specific material is not particularly limited. For example, it is preferably at least one selected from silver, aluminum, gold, bismuth, cadmium, cobalt, chromium, copper, dysprosium, erbium, iron, gallium, germanium, gadolinium, hafnium, holmium, indium, iridium, lithium, magnesium, molybdenum, niobium, nickel, lead, palladium, platinum, rhenium, rhodium, ruthenium, antimony, scandium, tin, tantalum, terbium, titanium, vanadium, tungsten, yttrium, zinc, zirconium, and SUS (stainless steel).

[0101] When the substrate 81 contains an alloy, its material is not particularly limited. For example, it is preferably at least one selected from aluminum alloys, gold alloys, cobalt alloys, chromium alloys, copper alloys, iron-based alloys, germanium alloys, magnesium alloys, manganese alloys, nickel alloys, palladium alloys, platinum alloys, titanium alloys, tungsten alloys, and zirconium alloys.

[0102] When the substrate 81 contains ceramics, its specific material is not particularly limited. For example, it is preferably at least one selected from borides, carbides, and nitrides in addition to oxides. Note that ceramics have some overlap with single-crystal materials, polycrystalline materials, and glass.

[0103] When the base material 81 contains a resin, the resin to be used is not particularly limited, but it is preferably one that does not cause problems in the surface state and durability of the base material containing the resin. Examples of the resin include polyester-based polymers such as polyethylene terephthalate, polyethylene naphthalate, and polyethylene-2,6-naphthalate; cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose; carbonate-based polymers such as polycarbonate; acrylic-based polymers such as polymethyl methacrylate; styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymer; olefin-based polymers such as polyethylene, polypropylene, and polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymer; vinyl chloride-based polymers; amide-based polymers such as aromatic polyamide; ether-based polymers such as polyethersulfone and polyetheretherketone; imide-based polymers; sulfone-based polymers; phenylene sulfide-based polymers; vinylidene chloride-based polymers; oxymethylene-based polymers; epoxy-based polymers; vinyl alcohol-based polymers; polyvinyl acetals such as polyvinyl butyral; and any resin selected from binary, ternary, and other various copolymers, graft copolymers, and blends of two or more resins selected from these resin groups. When the base material 81 contains a resin, the resin is particularly preferably one or more selected from polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polycarbonate, polymethyl methacrylate, and polyvinyl butyral. In particular, it is more preferable that the base material 81 is a biaxially oriented polyester film such as the above-mentioned polyethylene terephthalate in terms of mechanical properties, optical properties, heat resistance, and economy. The biaxially oriented polyester film may be a copolymerized polyester-based one.

[0104] The thickness of the base material 81 is not particularly limited and can be selected according to the strength required for the infrared shielding film, optical properties, etc. For example, it is preferably 0.001 mm or more and 100 mm or less, and more preferably 0.01 mm or more and 30 mm or less.

[0105] (2) When the infrared shielding film has a laminated structure The infrared shielding film may have a laminated structure, and from the viewpoint of exhibiting excellent infrared shielding performance by infrared reflection, it is preferably a laminated structure of a layer containing a molecular film aggregate and a layer containing a high refractive index material.

[0106] That is, in the infrared shielding film 80 shown in FIG. 8, instead of the region 801 where the molecular film aggregate 82 is arranged, it can also have a laminated structure. Specifically, for example, like the infrared shielding film 90 shown in FIG. 9, it can also have a laminated structure 91 on at least one surface 81A of the substrate 81. The laminated structure 91 can also include a high refractive index material 83 as part of the laminated structure 91 in addition to the aforementioned molecular film aggregate 82. Note that FIG. 9 is a schematic cross-sectional view of the infrared shielding film 90 of this embodiment in a plane along the lamination direction. Even when the infrared shielding film has a laminated structure, as shown in FIG. 9, the infrared shielding film may have a substrate, or may not have a substrate, that is, it may be composed only of the laminated structure 91.

[0107] In FIG. 9, an example is shown in which the infrared shielding film 90 with a laminated structure has two layers each of a layer containing the molecular film aggregate 82 and a layer containing the high refractive index material 83 alternately, but it is not limited to such a form. The infrared shielding film 90 with a laminated structure can also contain one layer each, or three or more layers each, of a layer containing the molecular film aggregate 82 and a layer containing the high refractive index material 83. Also, two or more types of molecular film aggregates and two or more types of high refractive index materials can be contained in the same layer or separate layers respectively. Furthermore, it can also have a layer containing a material other than the molecular film aggregate 82 and the high refractive index material 83. Also, like the infrared shielding film 110 shown in FIG. 11, it can also have an infrared shielding material such as infrared shielding material particles 101 different from the molecular film aggregate 82 and the high refractive index material 83.

[0108] In FIG. 9, although the example in which the laminated structure 91 including the molecular film aggregate 82 is disposed only on one surface 81A of the base material 81 is shown, the present invention is not limited to such a form. For example, the laminated structure 91 may be further disposed on the other surface 81B side of the base material 81. Further, a layer made of a molecular film aggregate 82 that is not a laminated structure, or a layer made of a high refractive index material 83 that is not a laminated structure may be disposed on the other surface 81B side of the base material 81.

[0109] Since the infrared shielding film of the laminated structure has a layer containing a high refractive index material, light of a specific wavelength corresponding to the refractive index difference is reflected at the interface of each layer, and it is possible to particularly shield light in the infrared region by controlling the film thickness of each layer.

[0110] The layer containing the high refractive index material only needs to contain the high refractive index material as described above, and may further contain a dispersion medium or a binder in which the high refractive index material is dispersed when forming the layer containing the high refractive index material. The layer containing the high refractive index material can also be composed only of the high refractive index material, but this case does not exclude the case of containing inevitable impurities.

[0111] The high refractive index material is not particularly limited, and for example, it is preferable to use a material having a refractive index of 2 or more.

[0112] As the high refractive index material, for example, one or more selected from titanium oxide, manganese oxide, tantalum oxide, niobium oxide, titanate, tantalate, niobate, and boron nitride can be preferably used. Since these materials have high visible light transparency, they do not reduce the infrared shielding performance. Further, since these materials can be obtained as a film having a thickness of about 1 nm by a soft chemical treatment similar to the molecular film of the present embodiment, the same process as the molecular film of the present embodiment can be adopted, which is advantageous in terms of cost. Furthermore, by laminating the molecular films, the film thickness of each layer can be easily controlled in units of 1 nm, and light of an arbitrary wavelength can be particularly shielded. (3) Regarding the characteristics of the infrared shielding film The optical properties of the infrared shielding film of the present embodiment are not particularly limited. For example, it is preferable that the maximum value of the light transmittance in the region of wavelengths from 400 nm to 780 nm is 50% or more, and the maximum value of the light reflectance in the region of wavelengths from 780 nm to 2600 nm is 50% or more.

[0113] By setting the maximum value of the light transmittance in the region of wavelengths from 400 nm to 780 nm, which is the visible light region, to 50% or more, visible light can be sufficiently transmitted. Also, by setting the maximum value of the light reflectance in the region of wavelengths from 780 nm to 2600 nm, which is the infrared region, to 50% or more, the light in the infrared region can be sufficiently shielded. Therefore, the infrared shielding film of the present embodiment having the above characteristics has excellent infrared shielding performance. [Manufacturing Method of Infrared Shielding Film] Next, the manufacturing method of the infrared shielding film of the present embodiment will be described. According to the manufacturing method of the infrared shielding film of the present embodiment, the above-described infrared shielding film can be manufactured. Therefore, the description of matters already explained will be omitted.

[0114] The manufacturing method of the infrared shielding film of the present embodiment can include the following first coating step and heat treatment step.

[0115] In the first coating step, a dispersion liquid containing a molecular film can be applied to the surface of the substrate.

[0116] In the heat treatment step, the substrate after the completion of the first coating step can be heat-treated in an atmosphere containing one or more selected from an inert gas and a reducing gas, or in a vacuum.

[0117] According to the manufacturing method of the infrared shielding film of the present embodiment, an infrared shielding film having a molecular film aggregate containing a molecular film of tungsten-oxygen octahedron blocks can be manufactured. The molecular film is, as described above, a composite tungsten oxide represented by the general formula M x W y O z or a tungsten oxide represented by the general formula W y O zIt can also contain tungsten oxide represented by . Also, the molecular film can have oxygen deficiency as described above.

[0118] Hereinafter, each step will be described. (1) First coating step In the first coating step, as described above, a dispersion containing a molecular film can be applied onto at least one surface of the substrate to obtain a molecular film assembly. Here, the dispersion containing the molecular film is referred to as the first coating solution.

[0119] In the dispersion containing the molecular film obtained as described above in the method for producing a molecular film, for example, for the purpose of applying it particularly uniformly onto the substrate during coating, a surfactant may be added to make the first coating solution. As the surfactant, various types such as nonionic, anionic, cationic, and amphoteric types can be used depending on the purpose and the material of the substrate.

[0120] The method for applying the first coating solution onto the substrate surface is not particularly limited, but it is preferable to apply it uniformly so that the substrate surface and the main surface of the molecular film are parallel. For example, wet methods such as the bar coating method, dip coating method, electrophoresis method, spray coating method, spin coating method, Langmuir-Blodgett method (LB method), layer-by-layer method, and the single-droplet deposition method (Single-Droplet method) described in Non-Patent Document 1 can be used to apply the first coating solution onto the substrate surface. Since the molecular film contained in the dispersion has a large aspect ratio, it is easy for the substrate surface and the main surface of the molecular film to be parallel with any coating method, and it is easy to apply it uniformly. Also, from the viewpoint of applying only a single layer of the molecular film over a wide range while integrating the molecular film, it is more preferable to adopt one or more selected from the spin coating method, Langmuir-Blodgett method, layer-by-layer method, and single-droplet deposition method. Among them, the single-droplet deposition method is particularly excellent in simplicity and the consumption amount of the molecular film can be minimized, so it can be particularly preferably used.

[0121] Note that after applying the first coating solution onto the substrate surface, drying or heat treatment can be performed at a temperature lower than the heat treatment temperature in the heat treatment step described later, if necessary. (2) Heat treatment process As described above, in the heat treatment process, after the first coating process, heat treatment can be performed in an atmosphere containing one or more selected from an inert gas and a reducing gas, or in a vacuum.

[0122] The reducing gas is not particularly limited, but H2 (hydrogen) is preferred. When using H2 as the reducing gas, as the composition of the reducing atmosphere, for example, it is preferable to mix H2 with an inert gas such as Ar or N2 in a volume ratio of more than 0% and 5.0% or less. The inert gas is not particularly limited, but one or more selected from the above-mentioned Ar and N2 are preferred from the viewpoint of cost.

[0123] The heat treatment temperature is not particularly limited either, but for example, 400 °C or higher and 900 °C or lower is preferable, and 500 °C or higher and 800 °C or lower is more preferable. By performing heat treatment at 400 °C or higher, oxygen deficiency can be introduced into the tungsten-oxygen octahedron block, and high infrared shielding performance can be exhibited. Also, by performing heat treatment at 900 °C or lower, generation of by-products, reaction between the molecular film and the substrate, sublimation of the molecular film, etc. can be suppressed. (3) Second coating process

[0124] As described above, the infrared shielding film of the present embodiment can also have a laminated structure containing a high refractive index material. Therefore, the manufacturing method of the infrared shielding film of the present embodiment can further include a second coating process of coating a second coating liquid containing a high refractive index material on the coating film of the first coating liquid before or after the heat treatment process, if necessary, after the first coating process.

[0125] Also, the above-mentioned first coating process and the second coating process can be repeatedly performed according to the number of layers to be laminated. And the above-mentioned heat treatment process can be arbitrarily performed before and after the coating process or between the first coating process and the second coating process.

[0126] The second coating liquid can contain a high refractive index material as described above. As described above, the high refractive index material is not particularly limited, but for example, it is preferable to use a material having a refractive index of 2 or more.

[0127] Also in the second coating liquid, the high refractive index material preferably has a sheet shape and more preferably is a molecular film. Therefore, the high refractive index material is preferably obtained by peeling from a material having a layered crystal structure. For example, one or more selected from titanium oxide, manganese oxide, tantalum oxide, niobium oxide, titanate, tantalate, niobate, and boron nitride can be suitably used.

[0128] Particularly, the high refractive index material is preferably titanium oxide, and the titanium oxide is, for example, Ti 1-α It is more preferably O2 (0.09 ≦ α ≦ 0.13). When preparing the second coating liquid, similar to the case of the first coating liquid, for example, first, composite titanium oxide having a layered crystal structure can be acid-treated with an acidic aqueous solution such as hydrochloric acid to be converted into a hydrogen-type substance or the like.

[0129] Next, for example, by inserting a bulky guest between the layers, it is possible to peel it into a single layer while maintaining the crystal structure of the high refractive index material to obtain a sheet-shaped molecular film. Specifically, a material that functions as a bulky guest can be mixed with the acid-treated product. Examples of the material that functions as a bulky guest include quaternary ammonium ions.

[0130] Therefore, the preparation process of the second coating liquid can include the following acid treatment process and a colloidalization process.

[0131] In the acid treatment process, a raw material having a layered crystal structure is brought into contact with an acid aqueous solution, and the product is washed and dried to obtain a hydrogen-type substance.

[0132] In the colloidalization process, a hydrogen-type substance and a liquid containing a bulky guest are mixed to obtain a molecular film of a high refractive index material.

[0133] And the dispersion liquid obtained after the colloidalization process can be used as the second coating liquid.

[0134] The case where the high refractive index material is titanium oxide will be described as an example, but the mechanism is the same as that of the composite tungsten oxide exemplified in the method for producing the molecular film. As the raw material of the titanium oxide, for example, a composite titanate having a layered crystal structure such as lithium potassium titanate is used. When this is subjected to acid treatment, lithium ions and potassium ions between the layers are exchanged with hydrogen ions and oxonium ions. Then, by adding a quaternary ammonium ion or the like that functions as a bulky guest, a titanium oxide molecular film peeled to one layer is obtained in a state of being dispersed in a liquid, that is, a dispersion containing the titanium oxide molecular film is obtained. Note that the raw material of the high refractive index material is not limited to the above form, and when it has a layered crystal structure, a dispersion containing a molecular film can be obtained by the same mechanism.

[0135] As the ions serving as the bulky guest, one or more selected from tetrabutylammonium ions, tetrapropylammonium ions, tetraethylammonium ions, tetramethylammonium ions, etc. can be used. As the ions serving as the bulky guest, tetrabutylammonium ion (TBA + ) can be particularly preferably used.

[0136] By subjecting the raw material of the high refractive index material that becomes titanium oxide to acid treatment, for example, a hydrogen-type substance represented by the general formula H β Ti 1-α O2·H2O (0 ≦ β ≦ 1, 0.09 ≦ α ≦ 0.13) can be obtained. And it is preferable to add so that the molar ratio of TBA + , which is an ion serving as a bulky guest, becomes 0.5 or more and 2 or less with respect to the amount of hydrogen ions in the above hydrogen-type substance.

[0137] The size of the resulting molecular film is not particularly limited, but it can have the thickness of a single layer of the layered compound, for example, it can have a thickness of about 1 nm or more and 2 nm or less. Further, the length in the longitudinal direction of the resulting molecular film can be, for example, 20 nm or more and 1 mm or less. That is, the aspect ratio can be, for example, 10 or more and 1,000,000 or less. The length of the molecular film can be adjusted by the synthesis conditions of the composite titanate having a layered crystal structure as a raw material, stirring of the dispersion containing the molecular film, ultrasonic irradiation, and the like.

[0138] In the second coating solution obtained as described above, for the purpose of, for example, coating particularly uniformly on the substrate when coating, a surfactant may be added. As the surfactant, various types such as nonionic, anionic, cationic, and amphoteric can be used depending on the purpose and the material of the substrate.

[0139] The method of applying the second coating solution to the substrate surface is the same as that of the first coating solution, so the description is omitted.

[0140] Further, after applying the second coating solution, drying or heat treatment at a temperature lower than the heat treatment temperature in the heat treatment step can be performed as necessary.

[0141] Further, the order of the first coating step and the second coating step can be reversed, and the second coating solution containing the high refractive index material can be applied directly onto the substrate.

[0142] (4) Separation step The method for manufacturing the infrared shielding film of the present embodiment can further have an arbitrary step, for example, it can have a separation step of separating the infrared shielding film from the substrate. Depending on the material of the substrate, for example, the infrared shielding film can be separated from the substrate by dissolving only the substrate or peeling the infrared shielding film from the substrate. The separated infrared shielding film can be placed on another substrate or disposed in the structure described later. [Structure] Next, the structure of the present embodiment will be described.

[0143] The structure of this embodiment can include the aforementioned molecular film. In the structure of this embodiment, the molecular film can also have the form of the aforementioned molecular film assembly or an infrared shielding film. Therefore, the structure of this embodiment can include one or more selected from a molecular film, a molecular film assembly, and an infrared shielding film.

[0144] The structure of this embodiment can also have, for example, a matrix such as a solid medium and the aforementioned molecular film disposed in the matrix. Also in this case, in the matrix, the molecular film can have the form of the aforementioned molecular film assembly or an infrared shielding film. Therefore, the structure of this embodiment can include a matrix and one or more selected from the molecular film, the molecular film assembly, and the infrared shielding film disposed in the matrix.

[0145] As described above, the structure of this embodiment can have a matrix of an appropriate solid medium such as resin and the aforementioned molecular film, which is a filler, disposed by kneading or the like in the matrix. The matrix generally refers to the base material, but here it refers to the solid medium in which a molecular film or the like, which is a filler, is kneaded.

[0146] The structure of this embodiment can have, for example, like the structure 120 shown in FIG. 12, a matrix 122 and an infrared shielding body 121 disposed in the matrix 122. The infrared shielding body 121 can be, for example, the aforementioned molecular film alone. Also, the infrared shielding body 121 can be the molecular film assembly 82 as illustrated in FIG. 12 or an infrared shielding film as will be described later.

[0147] The structure of this embodiment can have, for example, a structure similar to the structure 130 shown in FIG. 13, including a matrix 122 and an infrared shielding body 121 disposed within the matrix 122. In the case of the structure 130 shown in FIG. 13, an example is shown in which an infrared shielding film including a molecular film laminate 82 and a high refractive index material 83 is disposed on a substrate 81 as the infrared shielding body 121. When an infrared shielding film is used as the infrared shielding body 121, various infrared shielding films described with reference to FIGS. 8, 10, and 11 can be used as the infrared shielding body instead of the structure shown in FIG. 13.

[0148] Thus, the infrared shielding body 121 of the structure of this embodiment can also be kneaded into the matrix together with the substrate, such as an infrared shielding film like a molecular film laminate disposed on the substrate. That is, the structure can also include a substrate in the matrix, and more specifically, can include a substrate and an infrared shielding film having a molecular film laminate or the like disposed on the substrate.

[0149] Like the structure 140 shown in FIG. 14, the structure of this embodiment can also have a substrate. That is, the structure 140 can have a substrate 141 and a matrix 122 containing the above-described infrared shielding body 121 such as a molecular film provided on the substrate 141.

[0150] The configuration of the infrared shielding body 121 is not particularly limited. For example, as in the case of the structure 150 shown in FIG. 15, it can be a substrate 81 and an infrared shielding film having a molecular film laminate on the substrate 81. When an infrared shielding film is used as the infrared shielding body 121, various infrared shielding films described with reference to FIGS. 9 to 11 can be used as the infrared shielding body instead of the infrared shielding film of the structure shown in FIG. 15.

[0151] Also, like the structure 160 shown in FIG. 16, the structure of this embodiment can further contain infrared shielding material particles 161. The infrared shielding material particles 161 can be disposed, for example, within the matrix 122. The infrared shielding material particles 161 are members other than the molecular film, the molecular film laminate, and the infrared shielding film.

[0152] In the structure 160 as well, the infrared shielding material particles 161 and the matrix 122 containing the infrared shielding body 121 can be provided on the base material 141. Note that the structure 160 may not have the base material 141.

[0153] Since the structures shown in FIGS. 14 to 16 are formed on a base material, they can be classified as an infrared shielding film instead of a structure.

[0154] The matrix may be a molecular film or a molecular film aggregate or a matrix into which an infrared shielding film can be kneaded, and the material and its shape are not particularly limited. Since a structure in which a molecular film or the like is disposed in a solid medium is often used for a window material, a film for a vinyl greenhouse, etc., it preferably has any one of a sheet shape, a board shape, and a film shape. For this reason, the matrix also preferably has any one of a sheet shape, a board shape, and a film shape.

[0155] The material of the matrix is not particularly limited and can be selected according to the wavelength range of light to be transmitted, absorbed, and reflected required for the window material, and the strength, thickness, etc. required for the window material.

[0156] The matrix can contain the same material as the above-described base material in the infrared shielding film. However, from the viewpoints of simplicity and processability when kneading a molecular film or the like, and the light weight, economy, and durability as a window material, it preferably contains a resin. Since the resin has a low softening point, it is easy to obtain a matrix in a sheet shape, a board shape, or a film shape in which a filler such as a molecular film is kneaded by melt mixing and stretching.

[0157] The resin to be used is not particularly limited, but it is preferably one that does not cause problems in the surface state and durability of the matrix containing the resin. As the resin, for example, it can be suitably selected from the materials described in the case where the base material 81 contains resin in the "(1) When the infrared shielding film has a base material" of the above-described infrared shielding film. In particular, the resin is preferably one or more selected from polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polycarbonate, polymethyl methacrylate, and polyvinyl butyral, which is more suitable in terms of mechanical properties, optical properties, heat resistance, and economy. The polyester-based resin may be a copolymerized polyester-based resin.

Example

[0158] Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples.

[0159] [Example 1] (Preparation of the first coating liquid) First, the first coating liquid was prepared according to the following procedure.

[0160] 16.1 g of cesium carbonate and 40.0 g of tungsten(VI) oxide were mixed so that the Cs:W molar ratio was 6.3:11, and fired in an air atmosphere at 900 °C for 5 hours. From the powder X-ray diffraction pattern of the fired product, it was confirmed that Cs6W 11 O 36 was obtained. At the same time, it was also confirmed that the obtained Cs6W 11 O 36 has a repeating structure of tungsten-oxygen octahedron blocks as the basic skeleton. The powder X-ray diffraction pattern was measured by the powder X-ray diffraction method (θ-2θ method) using an X-ray diffractometer (Rigaku Corporation's fully automatic multi-purpose X-ray diffractometer SmartLab).

[0161] The obtained Cs6W 11 O 360.5 g was taken and immersed in 50 mL of 6 N hydrochloric acid. Then, it was mixed and shaken for 1 day at a shaking speed of 150 rpm using a shaker (Lab Shaker SR-1 manufactured by AS ONE Corporation), and acid treatment was performed at room temperature, that is, without heat treatment such as heating or cooling. Further, after removing the hydrochloric acid by decantation, it was replaced with fresh hydrochloric acid and the same acid treatment was additionally performed for 1 day, followed by filtration, washing with water, and air drying to recover the solid residue of the hydrogen-type substance which is the acid-treated product (acid treatment step).

[0162] When the Cs and W concentrations of the obtained solid residue were analyzed using an ICP emission spectrometer (ICPE-9000 manufactured by Shimadzu Corporation), they were 17 wt% and 64 wt%, respectively. Also, from the results, the chemical formula was calculated, and it was confirmed that the solid residue had a molar ratio of Cs / W = 4 / 11. In Table 1, in the column of the hydrogen-type substance, the mass ratios of the respective elements of the obtained hydrogen-type substance in the columns of the respective elements shown by Cs, Rb, and W are shown in the columns of Cs / W and Rb / W, and the molar ratios of Cs or Rb to W are shown respectively.

[0163] To 0.4 g of the obtained solid residue, 100 cm of an aqueous solution of tetrabutylammonium hydroxide with a concentration of 0.0029 mol / L 3 was added. Then, after mixing and shaking for 14 days at a shaking speed of 150 rpm using a shaker, the sediment components were removed by centrifugation, and a dispersion containing the molecular film of Cs4W 11 O 36 2- which is the first coating solution according to Example 1 was obtained (colloid formation step). Here, although the molecular film is obtained in a negatively charged state, the surface of the molecular film is modified with TBA of tetrabutylammonium ion + and is considered to be in a state close to neutral as a whole.

[0164] The obtained Cs4W 11 O 36 2-The molecular film dispersion was dropped onto a microgrid for transmission electron microscopy imaging, and the molecular film was transferred for morphological observation using a transmission electron microscope. For 10 molecular films subjected to morphological observation, it was confirmed that the average length in the longitudinal direction of the molecular film was 5 μm. Further, when the crystal structure was analyzed from the electron diffraction pattern of the molecular film, the obtained molecular film was found to have a molecular film with a repeating structure of tungsten-oxygen octahedron blocks as the basic skeleton, similar to Cs6W before acid treatment. 11 O 36 As for the above, it was confirmed that the molecular film has a repeating structure of tungsten-oxygen octahedron blocks as the basic skeleton. (Preparation of the second coating solution)

[0165] Potassium carbonate, lithium carbonate, titanium oxide, and molybdenum trioxide were mixed at a molar ratio of 1.67:0.13:1.73:1.27, fired at 1200 °C for 10 hours, and then slowly cooled at a rate of 4 °C per hour to 950 °C. Then, potassium molybdate, which is a flux component, was removed in pure water and air-dried to obtain a potassium lithium titanate single crystal, which is a precursor of a high refractive index material.

[0166] Next, 30 g of this single crystal was acid-treated in 2 dm of a 0.5 N hydrochloric acid solution at room temperature to obtain layered titanic acid crystals (H 3 Ti 0.54 Ti 0.87 O2·1.0H2O) with a size of 100 μm to 1 mm (acid treatment step).

[0167] Next, 100 cm of an aqueous solution of tetrabutylammonium hydroxide was added to 0.4 g of this layered titanic acid crystal, and the mixture was reacted at room temperature for 2 weeks in a stationary state, and the sediment component was removed by centrifugation (colloidization step). As a result, a milky white sol solution in which rectangular molecular films with a length of about 70 μm and a width of about 20 μm, represented by the general formula Ti 3 O2 0.87 O2 0.52- were dispersed was prepared. The molecular films in the second coating solution were morphologically observed using a transmission electron microscope. Here, although the molecular films are obtained in a negatively charged state, the surface of the molecular films is modified with TBA of tetrabutylammonium ions, and it is considered that the whole is in a state close to neutrality. + ions, and the whole is considered to be in a state close to neutrality.

[0168] The obtained sol was diluted 50-fold and adjusted to pH 9 to prepare a molecular film dispersion of titanium oxide, which is the second coating solution. The above dilution was performed by adding a dilution solution containing 2 wt% of polydiallyldimethylammonium chloride; polydiallyldimethylammonium chloride solution (hereinafter referred to as PDDA solution) 100 cm 3 to 0.5 moldm -3 corresponding amount of NaCl was added, and the pH was adjusted to 9.

[0169] The obtained first coating solution, Cs4W 11 O 36 2- of the molecular film dispersion was diluted 50-fold, coated on a quartz substrate with a thickness of 1 mm by a spin coater (ACT-300AII manufactured by Active Corporation), air-dried, and then heat-treated at 200 °C for 3 minutes in the atmosphere. This operation was repeated 5 times (the first coating step).

[0170] The X-ray diffraction pattern of the molecular film aggregate, which is a coating film of the molecular film formed on the quartz substrate, was measured by the in-plane X-ray diffraction method using an X-ray diffractometer. When the X-ray diffraction pattern was analyzed, it was confirmed that the molecular film aggregate contained a molecular film having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton. Also, since all the diffraction peaks were derived from the molecular film, it was confirmed that the obtained coating film contained the molecular film as the main component of the crystalline substance.

[0171] Next, the obtained second coating solution, Ti 0.87 O2 0.52- of the molecular film dispersion was coated, air-dried, and then heat-treated at 200 °C for 3 minutes in the atmosphere in the same manner. This operation was repeated 5 times (the second coating step).

[0172] A series of coating operations including the first coating step and the second coating step were alternately repeated one more time, and finally the first coating step was repeated one more time. Cs4W 11 O 362- A layer composed of 3 layers and Ti 0.87 O2 0.52- A precursor of an infrared shielding film in which two layers of a high refractive index material layer composed of were stacked was prepared.

[0173] Then, it was heated under the supply of a gas containing 4% H2 gas by volume with Ar gas as a carrier, and a reduction heat treatment was performed at 500 °C for 10 minutes. On one surface of the substrate, Cs4W 11 O z (z < 36) was obtained, which had a laminated structure of a layer having a molecular film aggregate and a layer having a high refractive index material made of titanium oxide. (Heat treatment step)

[0174] The X-ray diffraction pattern of the infrared shielding film according to Example 1 was measured by the grazing incidence X-ray diffraction method using an X-ray diffractometer. When the X-ray diffraction pattern was analyzed, it was confirmed that the infrared shielding film according to Example 1 contained a molecular film aggregate containing a molecular film having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton and a high refractive index material.

[0175] The infrared shielding film according to Example 1 was analyzed by X-ray photoelectron spectroscopy (XPS-Versa Probe II manufactured by Ulvac-PHI). Photoelectrons excited by irradiating with 25 W of Al-Kα X-rays were measured, and the W4f spectrum observed in the vicinity of 30 to 45 eV was separated into five peaks of W4f 7 / 2 6+ W4f 5 / 2 6+ W4f 7 / 2 5+ W4f 5 / 2 5+ W5p 3 / 2 . From the intensity area of each peak, the ratios of W valences of 6+ and 5+ were determined respectively. For W 6+ it was 95.03%, and for W 5+ it was 4.97%. Calculating the composition from this, z of Cs4W 11 O z was 35.7. That is, the composition of the molecular film constituting the molecular film aggregate in the infrared shielding film according to Example 1 was Cs4W11 O 35.7 It was confirmed that it is.

[0176] Here, the calculation method of z will be explained. Cs4W 11 O z The charged state of is not clear, but assuming that z takes the maximum value, similar to before heat treatment, Cs4W 11 O z is negatively charged with a charge state of -2. Since the valence of Cs is +1, considering the charge balance, 4×1 + 11×(95.03×6 + 4.97×5) / 100 - 2×z = -2. Solving this equation gives z = 35.7. The same calculation method was adopted in the following examples.

[0177] The transmittance and reflectance of the obtained infrared shielding film were evaluated using a spectrophotometer (U - 4100 manufactured by Hitachi, Ltd.).

[0178] When the light transmittance of the infrared shielding film was measured, it was 84% at a wavelength of 500 nm, 38% at a wavelength of 1300 nm, and 29% at a wavelength of 2000 nm.

[0179] Also, when the light reflectance of the infrared shielding film was measured, it was 28% at a wavelength of 1300 nm and 56% at a wavelength of 2000 nm.

[0180] That is, it was confirmed that the maximum value of the light transmittance in the region of wavelengths from 400 nm to 780 nm is 50% or more, and the maximum value of the light reflectance in the region of wavelengths from 780 nm to 2600 nm is 50% or more. Therefore, it was confirmed that the infrared shielding film obtained in this example has excellent infrared shielding performance.

[0181] The evaluation results are shown in Table 1. The evaluation results for the following other examples are also shown in Table 1 in the same manner.

[0182]

Table 1

[0183] Then, through the same heat treatment process as in Example 1, on one surface of the substrate, an infrared shielding film according to Example 2 having a molecular film assembly containing a molecular film composed of Cs4W 11 O z (z < 36) was obtained.

[0184] By evaluating the obtained molecular film assembly containing the molecular film in the same manner as in Example 1, it was confirmed that the molecular film having a repeating structure of tungsten-oxygen octahedron blocks as the basic skeleton was contained. Further, when analyzed by X-ray photoelectron spectroscopy, W 6+ was 95.12% and W 5+ was 4.88%. It was confirmed that the composition of the molecular film constituting the molecular film assembly in the infrared shielding film according to Example 2 was Cs4W 11 O 35.7 . In addition, in the calculation of the oxygen amount z, it was assumed that Cs4W 11 O z was negatively charged in a charge state of -2, as before the heat treatment.

[0185] The transmittance and reflectance of the obtained infrared shielding film were evaluated using a spectrophotometer (U-4100 manufactured by Hitachi, Ltd.).

[0186] When measuring the light transmittance of the infrared shielding film, it was 84% at a wavelength of 500 nm, 40% at a wavelength of 1300 nm, and 31% at a wavelength of 2000 nm.

[0187] Also, when measuring the light reflectance of the infrared shielding film, it was 25% at a wavelength of 1300 nm and 51% at a wavelength of 2000 nm.

[0188] The sheet resistance of the infrared shielding film according to Example 2 was measured using a sheet resistance measuring instrument (Mitsubishi Chemical's Loresta MP MCP-T350 or Highresista IP MCP-HT260), and it was 2.1×10 7 Ω / □ (ohm per square). [Example 3] (Preparation of the first coating solution)

[0189] 10.2 g of cesium carbonate and 40.0 g of tungsten(VI) oxide were mixed so that the Cs:W molar ratio was 4:11, and calcination was performed at 850 °C for 5 hours in an air atmosphere. From the powder X-ray diffraction pattern of the calcined product, it was confirmed that Cs4W 11 O 35 was obtained. At the same time, it was also confirmed that the obtained Cs4W 11 O 35 has a repeating structure of tungsten-oxygen octahedron blocks as the basic skeleton.

[0190] 0.5 g of the obtained Cs4W 11 O 35 was taken and added to 50 mL of 12N hydrochloric acid, and mixed and stirred at room temperature for 1 day, that is, without performing heat treatment such as heating or cooling, to perform acid treatment. Further, after removing the hydrochloric acid by decantation, it was replaced with fresh hydrochloric acid and the same acid treatment was additionally performed for 2 days (a total of 3 days of acid treatment), and filtration, washing with water, and air drying were performed to recover a solid residue that was the acid-treated product (acid treatment step).

[0191] The Cs and W concentrations of the obtained solid residue were analyzed by an ICP emission spectroscopic analyzer (ICPE-9000 manufactured by Shimadzu Corporation), and they were 13 wt% and 66 wt%, respectively. Also, from the results, the chemical formula was calculated, and it was confirmed that the solid residue had a molar ratio of Cs / W = 3 / 11.

[0192] To 0.4 g of the obtained solid residue, 100 cm 3 of a 0.0016 mol / L aqueous solution of tetrabutylammonium hydroxide was added, and after mixing and stirring at 200 rpm for 14 days, the precipitated components were removed by centrifugation, and Cs3W, which is the first coating solution according to Example 3, 11O 35 - A molecular film dispersion was obtained (colloid formation step). Here, although the molecular film is obtained in a negatively charged state, the surface of the molecular film is modified with TBA of tetrabutylammonium ion, and it is considered that the whole is in a state close to neutrality. +

[0193] The obtained Cs3W 11 O 35 - The molecular film dispersion of was dropped onto a microgrid for transmission electron microscope image observation, and the molecular film was transferred and the morphology was observed by a transmission electron microscope. For 10 molecular films subjected to morphology observation, it was confirmed that the average length in the longitudinal direction of the molecular film was 5 μm. Further, when the crystal structure was analyzed from the electron diffraction pattern of the molecular film, the obtained molecular film was the same as Cs4W before acid treatment 11 O 35 It was confirmed that the molecular film has a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton.

[0194] An infrared shielding film according to Example 3 having a molecular film assembly containing a molecular film composed of Cs3W 11 O z (z < 35) and a high refractive index material was obtained in the same manner as in Example 1 except that the first coating liquid according to Example 3 was used instead of the first coating liquid according to Example 1. When the first coating step in the middle was completed, it was confirmed that the molecular film assembly, which is a coating film of the molecular film formed on the quartz substrate, contains a molecular film having a repeating structure of tungsten-oxygen octahedron blocks as a main component of the crystalline substance.

[0195] By evaluating in the same manner as in Example 1, it was also confirmed that the infrared shielding film according to Example 3 contains a molecular film assembly containing a molecular film having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton and a high refractive index material. Further, when analyzed by X-ray photoelectron spectroscopy, W 6+ was 93.67% and W 5+ was 6.33%. The composition of the molecular film constituting the molecular film assembly in the infrared shielding film according to Example 3 was Cs3W 11 O​34.7 It was confirmed that it is. In the calculation of the oxygen amount z, similar to before the heat treatment, Cs3W 11 O z was assumed to be negatively charged with a charge state of -1.

[0196] Regarding the transmittance and reflectance of the infrared shielding film according to Example 3, evaluation was performed using a spectrophotometer.

[0197] When the light transmittance of the infrared shielding film was measured, it was 84% at a wavelength of 500 nm, 36% at a wavelength of 1300 nm, and 26% at a wavelength of 2000 nm.

[0198] Also, when the light reflectance of the infrared shielding film was measured, it was 32% at a wavelength of 1300 nm and 57% at a wavelength of 2000 nm. [Example 4] The series of coating operations in the first coating step according to Example 3 was repeated 5 times, and a precursor of an infrared shielding film composed only of Cs3W 11 O 35 was fabricated on a quartz substrate.

[0199] Then, through the same heat treatment process as in Example 3, on one surface of the substrate, Cs3W 11 O z (z < 35), an infrared shielding film according to Example 4 having a molecular film assembly containing a molecular film was obtained.

[0200] By evaluating the obtained molecular film assembly containing the molecular film in the same manner as in Example 1, it was confirmed that it contains a molecular film having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton. Also, when analyzed by X-ray photoelectron spectroscopy, W 6+ was 93.15% and W 5+ was 6.85%. It was confirmed that the composition of the molecular film constituting the molecular film assembly in the infrared shielding film according to Example 4 is Cs3W 11 O 34.6 . In the calculation of the oxygen amount z, similar to before the heat treatment, Cs3W 11 O z was assumed to be negatively charged with a charge state of -1.

[0201] The transmittance and reflectance of the obtained infrared shielding film were evaluated using a spectrophotometer (U-4100 manufactured by Hitachi, Ltd.).

[0202] When the light transmittance of the infrared shielding film was measured, it was 84% at a wavelength of 500 nm, 37% at a wavelength of 1300 nm, and 28% at a wavelength of 2000 nm.

[0203] Also, when the light reflectance of the infrared shielding film was measured, it was 30% at a wavelength of 1300 nm and 55% at a wavelength of 2000 nm.

[0204] When the sheet resistance of the infrared shielding film according to Example 4 was measured, it was 4.3×10 7 Ω / □ (ohm per square). [Example 5] Instead of 10.2 g of cesium carbonate, 7.24 g of rubidium carbonate was used, and instead of the acid treatment for 3 days, the acid treatment was carried out for 10 days. Instead of 100 cm 3 of 0.0016 mol / L tetrabutylammonium hydroxide aqueous solution, 100 cm 3 of 0.0014 mol / L tetrabutylammonium hydroxide aqueous solution was used. Except for the above points, in the same manner as in Example 3, Rb4W 11 O 35 having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton was synthesized as a fired product, and a molecular film dispersion liquid of Rb3W 11 O 35 - was obtained as the first coating liquid according to Example 5, and an infrared shielding film according to Example 5 having a molecular film assembly containing a molecular film composed of Rb3W 11 O z (z < 35) and a high refractive index material was produced. When the solid residue, which is the acid-treated product in the middle of the process, was recovered and the Rb and W concentrations were analyzed, they were 9 wt% and 70 wt%, respectively. Also, from the results, the chemical formula was calculated, and it was confirmed that the solid residue had a molar ratio of Rb / W = 3 / 11.

[0205] By evaluating in the same manner as in Example 1, it was also confirmed that the infrared shielding film according to Example 5 contains a molecular film integrated body including a molecular film having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton and a high refractive index material. Further, when analyzed by X-ray photoelectron spectroscopy, W 6+ was 95.57% and W 5+ was 4.43%. It was confirmed that the composition of the molecular film constituting the molecular film integrated body in the infrared shielding film according to Example 5 was Rb3W 11 O 34.8 . In the calculation of the oxygen amount z, it was assumed that Rb3W 11 O z was negatively charged with a charge state of -1, similar to before the heat treatment.

[0206] The transmittance and reflectance of the infrared shielding film according to Example 5 were evaluated using a spectrophotometer.

[0207] When the light transmittance of the infrared shielding film was measured, it was 80% at a wavelength of 500 nm, 39% at a wavelength of 1300 nm, and 29% at a wavelength of 2000 nm.

[0208] Also, when the light reflectance of the infrared shielding film was measured, it was 29% at a wavelength of 1300 nm and 50% at a wavelength of 2000 nm. [Example 6]

[0209] 5.01 g of bismuth(III) oxide and 4.99 g of tungsten(VI) oxide were mixed and heat-treated at 700 °C for 5 hours in an air atmosphere. It was confirmed from the powder X-ray diffraction pattern of the fired product that Bi2W2O9 was obtained.

[0210] 0.5 g of the obtained Bi2W2O9 was taken and added to 50 mL of 6 N hydrochloric acid, and mixed and stirred at room temperature for 3 days, that is, without performing heat treatment such as heating or cooling, to perform acid treatment. Further, after removing hydrochloric acid by filtration, it was replaced with fresh hydrochloric acid and the same acid treatment was additionally performed for 4 days, followed by decantation, washing with water, and air drying to recover a solid residue which was an acid-treated product (acid treatment step).

[0211] When the W concentration of the obtained solid residue was analyzed, it was 75 wt%. Also, Bi was not detected.

[0212] To 0.4 g of the obtained solid residue, 100 cm of an aqueous solution of tetrabutylammonium hydroxide with a concentration of 0.017 mol / L 3 was added, and in the same manner as in Example 1 except for this point, a molecular film dispersion of W2O7 2- which is the first coating liquid according to Example 6 was obtained (colloidization step), and an infrared shielding film according to Example 6 having a molecular film assembly containing a molecular film composed of W2O z (z < 7) and a high refractive index material was produced.

[0213] By evaluating in the same manner as in Example 1, it was also confirmed that the infrared shielding film according to Example 6 contains a molecular film assembly containing a molecular film having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton and a high refractive index material. Also, when analyzed by X-ray photoelectron spectroscopy, W 6+ was 93.80% and W 5+ was 6.20%, and it was confirmed that the composition of the molecular film constituting the molecular film assembly in the infrared shielding film according to Example 6 was W2O 6.94 . In the calculation of the composition, it was assumed that W2O z was negatively charged with a charge state of -2, as before the heat treatment.

[0214] The transmittance and reflectance of the infrared shielding film according to Example 6 were evaluated using a spectrophotometer.

[0215] When the light transmittance of the infrared shielding film was measured, it was 72% at a wavelength of 500 nm, 38% at a wavelength of 1300 nm, and 27% at a wavelength of 2000 nm.

[0216] Also, when the light reflectance of the infrared shielding film was measured, it was 23% at a wavelength of 1300 nm and 50% at a wavelength of 2000 nm.

[0217] [Example 7] 0.25 mL of the first coating liquid according to Example 3, 3.5 mL of pure water, and 0.042 mL of ethanol were mixed to prepare the first coating liquid according to Example 7. Using this, coating work was performed by the single droplet accumulation method. After heating a quartz substrate to a temperature of 120°C on a hot plate, the first coating liquid according to Example 7 was dropped onto the substrate and slowly sucked up with a pipette to prepare Cs3W 11 O 35 - A molecular film assembly composed of the above was fabricated on a quartz substrate.

[0218] Cs3W fabricated on a quartz substrate 11 O 35 - The surface of the molecular film assembly composed of the above was observed using an atomic force microscope (AFM) (AFM5100N, Hitachi High-Tech Corporation). Figure 6(A) shows an AFM image, and Figure 6(B) shows a cross-sectional profile taken along line X1-Y1 in Figure 6(A). Figure 6(A) shows that a molecular film coating with a size of about 100 to 1000 nm in the planar direction was obtained over the entire surface of the substrate with almost no gaps. Figure 6(B) shows that the thickness of the molecular film in the cross-sectional direction was about 3 nm.

[0219] Next, the substrate was subjected to the same heat treatment process as in Example 3, and an AFM image was observed. Fig. 7(A) shows an AFM image after the heat treatment, and Fig. 7(B) shows a cross-sectional profile taken along line X2-Y2 in Fig. 7(A). Fig. 7(A) shows that a molecular film coating having a size of about 100 to 1000 nm in the planar direction was obtained on the entire surface of the substrate with almost no gaps, as before the heat treatment. Fig. 7(B) shows that the thickness of the molecular film in the cross-sectional direction was about 3 nm.

[0220] After the coating process was repeated four more times, the substrate was subjected to a heat treatment process similar to that in Example 3, and then a Cs3W 11 O zAn infrared-shielding film according to Example 7 having a molecular film assembly including a molecular film composed of (z < 35) was obtained. When the first coating step in the middle thereof was completed, it was confirmed that the coating film of the molecular film formed on the quartz substrate contained, as a main component of the crystalline substance, a molecular film having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton.

[0221] By evaluating the obtained molecular film assembly containing the molecular film in the same manner as in Example 1, it was confirmed that the molecular film having a repeating structure of tungsten-oxygen octahedron blocks as a basic skeleton was contained. Further, when analyzed by X-ray photoelectron spectroscopy, W 6+ was 93.21%, and W 5+ was 6.79%. It was confirmed that the composition of the molecular film constituting the molecular film assembly in the infrared-shielding film according to Example 7 was Cs3W 11 O 34.6 . In the calculation of the composition, it was assumed that Cs3W 11 O z was negatively charged with a charge state of -1, as in the case before heat treatment.

[0222] The transmittance and reflectance of the infrared-shielding film according to Example 7 were evaluated using a spectrophotometer. When the light transmittance of the infrared-shielding film was measured, it was 82% at a wavelength of 500 nm, 33% at a wavelength of 1300 nm, and 24% at a wavelength of 2000 nm.

[0223] Also, when the light reflectance of the infrared-shielding film was measured, it was 32% at a wavelength of 1300 nm and 58% at a wavelength of 2000 nm.

[0224] When the sheet resistance of the infrared-shielding film according to Example 7 was measured, it was 3.6 × 10 7 Ω / □ (ohm per square).

[0225] [Example 8] First, the solvent of the first coating liquid according to Example 3 was replaced with toluene. 3 mL of toluene and 90 mL of methanol were added to 30 mL of the first coating liquid according to Example 3, and the solvent was evaporated using an evaporator until the liquid volume became 6 mL. Next, 30 mL of toluene and 90 mL of methanol were added, and the solvent was evaporated in the same manner until the liquid volume became 6 mL. Next, 90 mL of toluene and 30 mL of methanol were added, and the solvent was evaporated in the same manner until the liquid volume became 6 mL. Next, 120 mL of toluene and 0.4 g of a polymer dispersant were added, and the solvent (mostly toluene) was evaporated until it became 2% by mass to obtain a powder containing the molecular film according to Example 8. Note that as the polymer dispersant, a modified acrylic block copolymer having a group containing an amine as a functional group was used.

[0226] To 100 parts by mass of the obtained powder containing the molecular film, 1000 parts by mass of polyethylene terephthalate resin pellets and 10 parts by mass of a phosphorus-based antioxidant having a reducing action were mixed, melt-kneaded using a twin-screw extruder to obtain a kneaded product, and extruded into a string shape to obtain a string-like material. Note that the melting temperature during melt-kneading was 270°C. At this time, the string-like material was colored blue by melt-kneading, suggesting that oxygen deficiency was introduced into the molecular film by the reducing action of the phosphorus-based antioxidant.

[0227] The obtained string-like material was cut into pellets having a length of 4 mm to obtain a masterbatch.

[0228] After the obtained masterbatch was put into a single-screw extruder at 270°C, it was extruded onto a cooling roll through which a refrigerant at 65°C circulated by a melt extrusion molding method using a T-die to obtain a sheet having a thickness of 300 μm. The obtained sheet was cut into squares with sides of 5 cm, and biaxially stretched to form a film having a thickness of 40 μm to obtain a structure according to Example 8 having an infrared shielding function with polyethylene terephthalate as a matrix and the molecular film as a filler.

[0229] The transmittance and reflectance of the structure according to Example 8 were evaluated using a spectrophotometer. When the light transmittance of the structure was measured, it was 85% at a wavelength of 500 nm, 46% at a wavelength of 1300 nm, and 36% at a wavelength of 2000 nm.

[0230] Also, when the light reflectance of the infrared shielding film was measured, it was 21% at a wavelength of 1300 nm and 41% at a wavelength of 2000 nm.

[0231] Next, UV irradiation was performed for 20 minutes using a UV conveyor device (ECS-401GX, manufactured by Eye Graphic) to color the structure according to Example 8. At this time, a mercury lamp having a main wavelength of 365 nm was used as the UV source in the UV conveyor device, and the UV irradiation intensity was 100 mW / cm 2 . Thereafter, the transmittance was measured with a spectrophotometer in the same manner as before irradiation. It was 81% at a wavelength of 500 nm, 37% at a wavelength of 1300 nm, and 27% at a wavelength of 2000 nm, showing high chromic characteristics.

Explanation of Signs

[0232] 11 Tungsten-oxygen octahedron block 12 Void 13 M 31 Layer 32 Surface 61A, 61B, 71A, 71B Molecular film 62, 72 Gap 80, 90, 100, 110 Infrared shielding film 81 Substrate 81A One side 81B The other side 82 Molecular film assembly 83 High refractive index material 91 Laminated structure 101, 161 Infrared shielding material particles 120, 130, 140, 150, 160 Structure 121 Infrared shielding body 122 Matrix 141 Substrate

Claims

1. An infrared shielding film comprising a molecular film assembly containing a molecular film including tungsten-oxygen octahedron blocks, wherein the molecular film contains a composite tungsten oxide represented by the general formula MxWyOz (where M includes one or more selected from H, alkali metal elements, Ca, Sr, Ba, Fe, Cu, Ag, In, Tl, Sn, Pb, Yb, W is tungsten, O is oxygen, 0.001 ≦ x / y ≦ 1, 2.0 ≦ z / y ≦ 3.5), the maximum value of the light transmittance in the region of a wavelength of 400 nm or more and 780 nm or less is 50% or more, and the maximum value of the light reflectance in the region of a wavelength of 780 nm or more and 2600 nm or less is 50% or more.

2. The infrared shielding film according to Claim 1, wherein M includes one or more selected from Cs and Rb.

3. An infrared shielding film comprising a molecular film assembly containing a molecular film including tungsten-oxygen octahedron blocks, wherein the molecular film contains a tungsten oxide represented by the general formula WyOz (where W is tungsten, O is oxygen, 2.0 ≦ z / y < 3.5), the maximum value of the light transmittance in the region of a wavelength of 400 nm or more and 780 nm or less is 50% or more, and the maximum value of the light reflectance in the region of a wavelength of 780 nm or more and 2600 nm or less is 50% or more.

4. The infrared shielding film according to any one of Claims 1 to 3, wherein the molecular film has chromic properties.

5. A substrate, and the molecular film assembly disposed on the substrate, and the infrared shielding film according to any one of Claims 1 to 4.

6. The infrared shielding film according to Claim 5, wherein the substrate includes one or more selected from single crystal materials, polycrystalline materials, glass, metals, alloys, ceramics, and resins.

7. The infrared shielding film according to any one of Claims 1 to 6, having a laminated structure.

8. The infrared shielding film according to Claim 7, containing a high refractive index material as a part of the laminated structure.

9. The infrared shielding film according to Claim 8, wherein the high refractive index material is one or more selected from titanium oxide, manganese oxide, tantalum oxide, niobium oxide, titanates, tantalates, niobates, and boron nitride.

10. A structure including the infrared shielding film according to any one of Claims 1 to 9.

11. A matrix, and the infrared shielding film disposed in the matrix, and the structure according to Claim 10.

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