Infrared-shielding fibrous structure

Abstract

To provide an infrared-shielding fibrous structure capable of preventing secret photography with infrared radiation and having superior resistance to chemicals.SOLUTION: An infrared-shielding fibrous structure, comprises a fabric that includes organic-inorganic hybrid infrared-shielding particles and fibers, wherein the organic-inorganic hybrid infrared-shielding particles include infrared-shielding particles and a coating resin covering at least part of the surface of the infrared-shielding particles, and wherein the content of the infrared-shielding particles per unit area of the infrared-shielding fibrous structure is 0.10 g / m2 or more and 4.5 g / m2 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an infrared-shielding textile structure. [Background technology]

[0002] In recent years, it has become known that when natural light is used as a light source and an image of a human body is taken with an image sensor equipped with a special filter, the infrared rays contained in the natural light can penetrate through clothing and capture the image of the human body. Criminal acts exploiting this phenomenon, known as voyeurism, have become a social problem.

[0003] In order to solve the above problems, infrared-shielding fibers that absorb or reflect infrared rays have been produced, and clothing made from these infrared-shielding fibers has been studied and developed.

[0004] For example, Patent Document 1 discloses a knitted fabric obtained by adhering one or more infrared absorbers selected from anthraquinone-based, indigo-based, benzoquinone-based, naphthoquinone-based, and phthalocyanine-based materials to core-sheath synthetic fibers.

[0005] Patent Document 2 discloses a fabric or clothing for preventing fluoroscopy, in which a thin film made of metal, carbide, metal carbide, or ceramic is formed by an appropriate means on the surface of fabric used in underwear and the like that is worn in close contact with the human body, and the thin film reflects or absorbs infrared rays, making it possible to prevent fluoroscopy.

[0006] Patent Document 3 discloses near-infrared absorbing fibers containing tungsten oxide microparticles and / or composite tungsten oxide microparticles on the surface and / or inside thereof, and textile products obtained by processing the near-infrared absorbing fibers. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-223171 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-42252 [Patent Document 3] International Publication No. 2006 / 049025 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in both Patent Documents 1 and 2, the chemical resistance is insufficient, and there is a risk that the function of preventing surreptitious photography using infrared rays may be reduced by repeated contact with chemicals such as detergent during laundry, for example.

[0009] Patent Document 3 is an invention relating to a low-cost fiber with heat retention properties and a textile product using said fiber, and is not intended to prevent fluoroscopic photography using infrared rays, as in Patent Document 1, etc. Therefore, the near-infrared absorbing fiber and textile product of Patent Document 3 cannot be diverted to the purpose of preventing fluoroscopic photography using infrared rays.

[0010] Therefore, one aspect of the present invention aims to provide an infrared-shielding fiber structure that has the function of preventing surreptitious photography using infrared rays and also has excellent chemical resistance. [Means for solving the problem]

[0011] In one aspect of the present invention, there is provided an infrared shielding textile structure, comprising: The fabric includes organic-inorganic hybrid infrared shielding particles and fibers, The organic-inorganic hybrid infrared shielding particles include infrared shielding particles and a coating resin that covers at least a part of the surface of the infrared shielding particles, The content of the infrared-shielding particles per unit area of ​​the infrared-shielding fiber structure is 0.10 g / m 2 More than 4.5g / m 2 The following infrared-shielding textile structure is provided: [Effects of the Invention]

[0012] According to one aspect of the present invention, an infrared-shielding fiber structure can be provided that has a function of preventing surreptitious photography using infrared rays and also has excellent chemical resistance. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional schematic diagram of an infrared-shielding fiber that can be used in the infrared-shielding fiber structure of this embodiment. [Figure 2] FIG. 2 is a cross-sectional schematic diagram of an infrared-shielding fiber structure of this embodiment having a cured resin film. DETAILED DESCRIPTION OF THE INVENTION

[0014] Specific examples of an infrared-shielding fiber structure according to one embodiment of the present disclosure (hereinafter referred to as "the present embodiment") will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0015] In this specification, the names of components, etc., such as the first surface and the second surface, may be described with "first" or "second" added, but "first" or "second" is merely used to distinguish between the components and to prevent confusion during description. Therefore, "first" or "second" does not represent placement, priority, etc. Furthermore, when there is no particular risk of confusion or when referring to components collectively, they may be simply written as "surface," etc. [Infrared shielding textile structure] The infrared-shielding fiber structure of the present embodiment has a substrate including organic-inorganic hybrid infrared-shielding particles and fibers. The organic-inorganic hybrid infrared-shielding particles include infrared-shielding particles and a coating resin that covers at least a portion of the surface of the infrared-shielding particles.

[0016] The infrared-shielding fiber structure of this embodiment has an infrared-shielding particle content per unit area of ​​0.10 g / m 2 More than 4.5g / m 2It can be as follows:

[0017] The inventors of the present invention discovered that by using the above-mentioned organic-inorganic hybrid infrared-shielding particles, it is possible to produce an infrared-shielding fiber structure that has the function of preventing surreptitious photography using infrared rays and also has excellent chemical resistance, and thus completed the present invention.

[0018] Each component of the infrared shielding fiber structure of this embodiment will be described below. <Organic-inorganic hybrid infrared shielding particles> An example of a method for producing organic-inorganic hybrid infrared-shielding particles will be described below, followed by a description of the organic-inorganic hybrid infrared-shielding particles.

[0019] (1) Manufacturing method of organic-inorganic hybrid infrared shielding particles The method for producing the organic-inorganic hybrid infrared shielding particles may include, for example, the following dispersion preparation step, dispersion medium reduction step, raw material mixture preparation step, stirring step, and polymerization step.

[0020] In the dispersion preparation step, a dispersion containing infrared shielding particles, a dispersant, and a dispersion medium can be prepared.

[0021] In the dispersion medium reducing step, the dispersion medium can be evaporated from the dispersion liquid.

[0022] In the raw material mixture preparation step, the infrared shielding particles recovered after the dispersion medium reduction step, the coating resin raw material, the organic solvent, the emulsifier, water, and the polymerization initiator are mixed to prepare the raw material mixture.

[0023] In the stirring step, the raw material mixture can be stirred while being cooled.

[0024] In the polymerization step, a deoxidation treatment for reducing the amount of oxygen in the raw material mixture can be carried out, and then the polymerization reaction of the coating resin raw material can be carried out.

[0025] Each step will be described below. (1-1) Dispersion liquid preparation process In the dispersion preparation step, a dispersion containing infrared shielding particles, a dispersant, and a dispersion medium can be prepared.

[0026] Each material that can be suitably used when preparing the dispersion in the dispersion preparation step will be described below. (a) Infrared shielding particles In the dispersion preparation step, various infrared-shielding particles that are required to have improved chemical resistance, such as acid resistance or alkali resistance, can be used as the infrared-shielding particles. For example, it is preferable to use infrared-shielding particles containing various materials that contain free electrons, and it is more preferable to use infrared-shielding particles containing various inorganic materials that contain free electrons. (a-1) Compounds contained in infrared shielding particles The infrared shielding particles may contain various compounds having infrared shielding properties, but preferably contain at least one selected from tungsten oxides having oxygen deficiency and composite tungsten oxides.

[0027] The tungsten oxide having oxygen vacancies can be represented by the general formula W y O z (W: tungsten, O: oxygen, 2.2≦z / y≦2.999).

[0028] The composite tungsten oxide can be, for example, a compound represented by the general formula M x W y O zThe element M in the above general formula can be represented by H (hydrogen), He (helium), alkali metal elements, alkaline earth metal elements, rare earth elements, Mg (magnesium), Zr (zirconium), Cr (chromium), Mn (manganese), Fe (iron), Ru (ruthenium), Co (cobalt), Rh (rhodium), Ir (iridium), Ni (nickel), Pd (palladium), Pt (platinum), Cu (copper), Ag (silver), Au (gold), Zn (zinc), Cd (cadmium), Al (aluminum), Ga (gallium), In (indium), The element may be one or more elements selected from the group consisting of Tl (thallium), Si (silicon), Ge (germanium), Sn (tin), Pb (lead), Sb (antimony), B (boron), F (fluorine), P (phosphorus), S (sulfur), Se (selenium), Br (bromine), Te (tellurium), Ti (titanium), Nb (niobium), V (vanadium), Mo (molybdenum), Ta (tantalum), Re (rhenium), Be (beryllium), Hf (hafnium), Os (osmium), Bi (bismuth), and I (iodine).

[0029] Examples of alkali metal elements include Li (lithium), Na (sodium), K (potassium), Rb (rubidium), Cs (cesium), and Fr (francium).

[0030] Examples of alkaline earth metal elements include Ca (calcium), Sr (strontium), Ba (barium), and Ra (radium).

[0031] Examples of rare earth elements include Sc (scandium), Y (yttrium), La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), and Lu (lutetium).

[0032] The above composite tungsten oxide has the general formula M x W y Oz Preferably, x, y, and z satisfy the conditions 0.001≦x / y≦1 and 2.0≦z / y<4.0.

[0033] The infrared shielding particles are represented by the general formula M x W y O z The infrared shielding particles preferably contain a composite tungsten oxide represented by the general formula M x W y O z It may be made of a composite tungsten oxide, but even in this case, it does not exclude the inclusion of unavoidable impurities.

[0034] It is generally known that materials containing free electrons exhibit a reflection / absorption response to electromagnetic waves in the wavelength range of 200 nm to 2600 nm, around the wavelength of sunlight, due to plasma oscillation. Therefore, various materials containing free electrons can be suitably used as infrared-shielding particles. For example, infrared-shielding particles made smaller than the wavelength of light can reduce geometric scattering in the visible light range (wavelengths of 380 nm to 780 nm), which is preferable because they can achieve particularly high transparency in the visible light range.

[0035] In this specification, the term "transparency" is used to mean "high transmittance with little scattering of light in the visible light range."

[0036] Composite tungsten oxides, which are made by adding electropositive elements such as Na to WO3, are known to be conductive materials with free electrons. Analysis of single crystals of these materials with free electrons has suggested that the free electrons respond to light in the infrared region.

[0037] According to the investigations of the present inventors, there is a specific range within the composition range of tungsten and oxygen that is particularly effective as an infrared-shielding material, and it is possible to obtain a composite tungsten oxide that is transparent in the visible light region and has particularly strong shielding properties in the infrared region.

[0038] Therefore, the composite tungsten oxide, which is one type of material for infrared shielding particles that can be suitably used in the dispersion preparation step, will be further described below. (a-2) Composite tungsten oxide Composite tungsten oxide is made by adding element M to WO3.

[0039] By adding element M to form a composite tungsten oxide, free electrons are generated in the WO3, and strong shielding properties derived from the free electrons are manifested, particularly in the near-infrared region, making the particles effective at blocking near-infrared light with a wavelength of around 1000 nm.

[0040] That is, by controlling the amount of oxygen and adding the element M that generates free electrons to WO3 to form a composite tungsten oxide, it is possible to exhibit more efficient infrared shielding properties. The general formula of the composite tungsten oxide that controls the amount of oxygen and adds the element M that generates free electrons to WO3 is M x W y O z When the formula is written as follows, it is preferable to satisfy the relationships 0.001≦x / y≦1 and 2.0≦z / y<4.0. In the above general formula, M represents the element M already described, W represents tungsten, and O represents oxygen.

[0041] As described above, when the value of x / y, which indicates the amount of element M added, is 0.001 or more, a particularly sufficient amount of free electrons is generated in the composite tungsten oxide, and a high infrared shielding effect can be obtained. The greater the amount of element M added, the greater the supply of free electrons and the higher the infrared shielding efficiency, but this effect saturates when the value of x / y is about 1. Furthermore, when the value of x / y is 1 or less, this is preferable because it is possible to avoid the generation of impurity phases in the infrared shielding particles containing the composite tungsten oxide.

[0042] Elements suitable for use as element M in the general formula of the composite tungsten oxide have already been described, and therefore further description will be omitted. Furthermore, from the viewpoint of particularly enhancing the stability of the composite tungsten oxide, element M is more preferably one or more elements selected from 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, and Re. Furthermore, from the viewpoint of improving the optical properties and weather resistance of the infrared-shielding particles containing the composite tungsten oxide, element M is even more preferably one or more elements selected from alkali metal elements, alkaline earth metal elements, transition metal elements, Group 4B elements, and Group 5B elements.

[0043] General formula W y O z In the case of tungsten oxide represented by the formula (1), by making z / y less than 3 and causing oxygen deficiency, a particularly sufficient number of free electrons are generated to enhance the absorption and reflection characteristics in the infrared region, resulting in efficient infrared absorbing particles.

[0044] General formula M x W y O z In the composite tungsten oxide expressed as y O z However, in the composite tungsten oxide, in addition to the above mechanism, even when z / y=3.0 or when the amount of added oxygen is excessive and exceeds 3.0, free electrons are supplied by the amount of added element M as described above. Therefore, the value of z / y, which indicates the amount of added oxygen in the composite tungsten oxide, is preferably 2.0≦z / y<4.0, more preferably 2.2≦z / y<4.0, and even more preferably 2.45≦z / y<4.0.

[0045] In particular, when the composite tungsten oxide has a hexagonal crystal structure, the infrared-shielding particles containing the composite tungsten oxide have improved light transmission in the visible light range, and improved light shielding in the infrared range.

[0046] When the composite tungsten oxide has a hexagonal crystal structure, six octahedra formed by WO units are assembled to form a hexagonal void, and an element M is placed in the void to form one unit. A large number of these units are assembled to form the hexagonal crystal structure.

[0047] In order to improve the transmission of light in the visible light region and the blocking of light in the infrared region, it is sufficient for the composite tungsten oxide to contain the above-mentioned unit structure, and therefore the composite tungsten oxide may be crystalline or amorphous.

[0048] When cations of element M are added and present in the above-mentioned hexagonal voids, light transmission in the visible light region is improved, and light shielding properties in the infrared region are improved. Generally, the hexagonal crystal is easily formed when an element M with a large ionic radius is added. Specifically, the hexagonal crystal is easily formed when one or more elements selected from Cs, K, Rb, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn are added as the element M. Of course, elements other than these may also be used as long as the above-mentioned element M is present in the hexagonal voids formed by the WO6 units, and the present invention is not limited to the above-mentioned elements.

[0049] In order for the composite tungsten oxide having a hexagonal crystal structure to have a uniform crystal structure, the amount of element M added is preferably such that the value of x / y in the general formula described above is 0.2 or more and 0.5 or less, more preferably 0.33. It is believed that when the value of x / y is 0.33, the element M described above is arranged in all of the hexagonal voids.

[0050] In addition, infrared shielding particles containing composite tungsten oxides other than hexagonal crystals, such as tetragonal and cubic crystals, also have sufficiently effective infrared shielding properties. The shielding position in the infrared region tends to change depending on the crystal structure, with the shielding position tending to shift toward longer wavelengths in the order of cubic crystals < tetragonal crystals < hexagonal crystals. Concomitantly, the order of crystals with the least shielding properties for visible light is hexagonal, tetragonal, and cubic crystals. Therefore, for applications requiring greater transmission of visible light and greater shielding of infrared light, it is preferable to use a hexagonal composite tungsten oxide. However, the optical properties described here are merely rough trends, and may vary depending on the type and amount of added element and the amount of oxygen, and the present invention is not limited thereto. (a-3) Particle size of infrared shielding particles The particle size of the infrared shielding particles is not particularly limited and can be selected depending on the intended use and the like.

[0051] First, when used in applications where colorlessness must be maintained, that is, when used in applications where high transparency is required, the infrared-shielding particles preferably have a particle size of 800 nm or less. Considering the design properties, such as dyeability, of an infrared-shielding fiber structure in which organic-inorganic hybrid infrared-shielding particles are arranged at one or more positions selected from the surface and the interior of a fiber, it is preferable that the infrared-shielding particles be able to efficiently absorb and shield near-infrared rays while maintaining transparency.

[0052] When infrared-shielding particles contain tungsten oxide or composite tungsten oxide, they transmit light in the visible light region (wavelengths of 380 nm to 780 nm) and significantly absorb light in the near-infrared region, particularly light in the wavelength range of 780 nm to 2200 nm. Therefore, the transmitted color tone is often blue to green. Therefore, it is preferable to increase transparency by making the particle size (particle diameter) of the infrared-shielding particles smaller than 800 nm. However, when transparency is particularly important and particularly high transparency is required, it is more preferable to make the particle size 200 nm or less, and even more preferably 100 nm or less. On the other hand, since industrial production is easier if the particle size is 1 nm or more, the particle size of the infrared-shielding particles may be 1 nm or more to 800 nm or less.

[0053] The number average particle size of the infrared shielding particles preferably also satisfies the above range.

[0054] Furthermore, since the infrared-shielding particles are processed into organic-inorganic hybrid infrared-shielding particles, the particle size of the infrared-shielding particles affects particle size characteristics such as the median particle size of the organic-inorganic hybrid infrared-shielding particles. Since it is desirable for the D50, which is the median particle size of the particle size distribution of the organic-inorganic hybrid infrared-shielding particles, to be 1 μm or less, the particle size of the infrared-shielding particles is preferably 800 nm or less. The particle size of the infrared-shielding particles is more preferably 200 nm or less, and even more preferably 100 nm or less.

[0055] If the particle size of the infrared-shielding particles is 800 nm or less, when they are processed into organic-inorganic hybrid infrared-shielding particles having a median diameter D50 of the particle size distribution of 1 μm or less, the surfaces of the infrared-shielding particles can be covered with a coating resin.

[0056] The particle size of the infrared shielding particles can be measured using a TEM (transmission electron microscope) image.

[0057] The particle size of the infrared shielding particle can be the diameter of the smallest circle that can be drawn around the infrared shielding particle. (a-4) Manufacturing method of infrared shielding particles Next, regarding the method for producing infrared shielding particles, the general formula WO z and tungsten oxide particles represented by the general formula M x W y O z The method for producing composite tungsten oxide particles represented by the formula (I) will be described below as an example.

[0058] Tungsten oxide particles and composite tungsten oxide particles can be obtained, for example, by heat treating the starting material of the oxide particles in an inert gas atmosphere or a reducing gas atmosphere. In the case of tungsten oxide particles, a tungsten source, which is a material containing tungsten, can be used as the starting material. In the case of composite tungsten oxide particles, a tungsten-element M-containing material, which is a material containing tungsten and element M, can be used as the starting material. As the tungsten-element M-containing material, for example, a mixture of a tungsten source, which is a material containing tungsten, and an element M source, which is a material containing element M, can also be used. As the tungsten-element M-containing material, a compound containing tungsten and element M at the same time can be used.

[0059] The tungsten source and the element M source used as starting materials may contain tungsten and the element M, respectively, as a single element or in the form of a compound or the like.

[0060] The tungsten source used as the starting material may be one or more selected from the group consisting of tungsten trioxide powder, tungsten dioxide powder, tungsten oxide hydrate, tungsten hexachloride powder, ammonium tungstate powder, tungsten oxide hydrate powder obtained by dissolving tungsten hexachloride in alcohol and then drying, tungsten oxide hydrate powder obtained by dissolving tungsten hexachloride in alcohol and then adding water to precipitate and then drying the precipitate, tungsten compound powder obtained by drying an aqueous solution of ammonium tungstate, and metallic tungsten powder.

[0061] From the viewpoint of ease of the production process, it is more preferable to use, as the tungsten source, one or more types selected from the group consisting of tungsten oxide hydrate powder, tungsten trioxide, and tungsten compound powder obtained by drying an aqueous solution of ammonium tungstate.

[0062] When producing composite tungsten oxide particles, if the starting material is a solution, each element can be easily mixed uniformly. Therefore, when producing composite tungsten oxide particles, one or more tungsten sources selected from an ammonium tungstate aqueous solution, a tungsten hexachloride solution, etc. can be used.

[0063] The starting material for the composite tungsten oxide particles may further contain an element M source that supplies the element M. It is preferable that the tungsten source and the element M source are thoroughly mixed, and it is more preferable that the components are uniformly mixed at the molecular level. The starting material for the composite tungsten oxide particles may be a compound containing the element M and tungsten.

[0064] For this reason, the starting material for the composite tungsten oxide particles is preferably a mixture of a tungsten source and an element M source in a solution, and the tungsten compound containing element M may be soluble in a solvent such as water or an organic solvent. For example, the element M source used as the starting material for the composite tungsten oxide particles may be one or more selected from tungstates, chlorides, nitrates, sulfates, oxalates, oxides, carbonates, hydroxides, etc., containing element M. However, the element M source is not limited to these, and any source that can be in solution form can be suitably used.

[0065] The raw materials for producing the above-mentioned tungsten oxide particles and composite tungsten oxide particles will be described in detail again below.

[0066] General formula WO zThe tungsten source, which is the starting material for obtaining the tungsten oxide particles represented by the formula (I), can be one or more selected from tungsten trioxide powder, tungsten dioxide powder, tungsten oxide hydrate, tungsten hexachloride powder, ammonium tungstate powder, tungsten oxide hydrate powder obtained by dissolving tungsten hexachloride in alcohol and then drying, tungsten oxide hydrate powder obtained by dissolving tungsten hexachloride in alcohol and then adding water to precipitate and then drying the precipitate, tungsten compound powder obtained by drying an aqueous solution of ammonium tungstate, metallic tungsten powder, and tungstic acid. From the viewpoint of ease of production process, it is more preferable to use, as the tungsten source, tungsten oxide hydrate powder, tungsten trioxide powder, or tungsten compound powder obtained by drying an aqueous solution of ammonium tungstate.

[0067] General formula M containing element M x W y O z The starting material for obtaining the composite tungsten oxide particles represented by the formula (I) can be a powder obtained by mixing one or more powders selected from tungsten trioxide powder, tungsten dioxide powder, tungsten oxide hydrate, tungsten hexachloride powder, ammonium tungstate powder, tungsten oxide hydrate powder obtained by dissolving tungsten hexachloride in alcohol and then drying, tungsten oxide hydrate powder obtained by dissolving tungsten hexachloride in alcohol and then adding water to precipitate and then drying the precipitate, tungsten compound powder obtained by drying an aqueous solution of ammonium tungstate, metallic tungsten powder, and tungstic acid with a powder of a simple substance or compound containing the above-mentioned M element.

[0068] Furthermore, when the tungsten compound, which is the starting material for obtaining the composite tungsten oxide particles, is in the form of a solution or dispersion, the elements can be easily mixed uniformly.

[0069] From this perspective, the starting material for the composite tungsten oxide particles may be a powder obtained by mixing an alcohol solution of tungsten hexachloride or an aqueous solution of ammonium tungstate with a solution of the compound containing the M element, followed by drying.

[0070] Similarly, the starting material for the composite tungsten oxide particles may be a dispersion obtained by dissolving tungsten hexachloride in alcohol, adding water to form a precipitate, and mixing this dispersion with a powder of a simple substance or compound containing the M element, or a solution of a compound containing the M element, followed by drying the resulting powder.

[0071] Examples of compounds containing the element M include, but are not limited to, tungstates, chlorides, nitrates, sulfates, oxalates, oxides, carbonates, and hydroxides of the element M. Any compound that can be formed into a solution may be used. Furthermore, when producing composite tungsten oxide particles industrially, using tungsten oxide hydrate powder or tungsten trioxide and a carbonate or hydroxide of the element M is a preferred production method, since no harmful gases are generated during heat treatment or other steps.

[0072] The raw materials described above can be used and heat-treated in an inert gas atmosphere or a reducing gas atmosphere to obtain infrared-shielding particles containing one or more tungsten oxides and composite tungsten oxides having infrared-shielding properties.

[0073] Here, the heat treatment conditions in an inert atmosphere when producing tungsten oxide or composite tungsten oxide are preferably 650°C or higher. Starting materials heat-treated at 650°C or higher have sufficient infrared shielding function and are efficient as particles with infrared shielding function. The heat treatment temperature in the inert atmosphere may be, for example, 650°C or higher and 1200°C or lower. As the inert gas, it is preferable to use an inert gas such as Ar or N2.

[0074] The heat treatment conditions in a reducing atmosphere are preferably as follows: first, the starting material is heat-treated in a reducing gas atmosphere at 100°C to 850°C, and then in an inert gas atmosphere at 650°C to 1200°C. The reducing gas used here is not particularly limited, but H2 (hydrogen) is preferred. When H2 is used as the reducing gas, the composition of the reducing atmosphere preferably contains 0.1% or more H2 by volume, more preferably 2% or more. If the volume ratio of H2 is 0.1% or more, reduction can proceed efficiently. Since the reducing gas can also be composed of hydrogen, the reducing atmosphere can contain 100% or less H2 gas by volume. (b) Dispersant The dispersant is used for the purpose of hydrophobizing the surface of the infrared shielding particles. The dispersant can be selected according to the dispersion system, which is a combination of the infrared shielding particles, the dispersion medium, the coating resin raw material, etc. Among them, a dispersant having one or more functional groups selected from an amino group, a hydroxyl group, a carboxyl group, a sulfo group, a phospho group, and an epoxy group can be preferably used. When the infrared shielding particles contain a composite tungsten oxide, it is more preferable that the dispersant have an amino group as the functional group.

[0075] As described above, the dispersant preferably has an amino group as a functional group, i.e., is an amine compound, and the amine compound is more preferably a tertiary amine.

[0076] Furthermore, since the dispersant is used for the purpose of hydrophobizing the surface of the infrared shielding particles, it is preferably a polymeric material. Therefore, the dispersant preferably has one or more selected from, for example, a long-chain alkyl group and a benzene ring, and more preferably, a polymeric dispersant having a copolymer of styrene and 2-(dimethylamino)ethyl methacrylate, a tertiary amine, in the side chain, which can also be used as a coating resin raw material. The long-chain alkyl group preferably has 8 or more carbon atoms. For example, a dispersant that is both a polymeric material and an amine compound can also be used.

[0077] The amount of dispersant added is not particularly limited and can be selected arbitrarily. The suitable amount of dispersant added can be selected depending on the type of dispersant and infrared-shielding particles, the specific surface area of ​​the infrared-shielding particles, and the like. For example, it is preferable to add 10 parts by mass or more and 500 parts by mass or less of the dispersant relative to 100 parts by mass of the infrared-shielding particles, since this makes it easier to prepare a dispersion in a particularly well-dispersed state. The amount of dispersant added is more preferably 10 parts by mass or more and 100 parts by mass or less, and even more preferably 15 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the infrared-shielding particles. (c) Dispersion medium The dispersion medium may be any medium that can disperse the infrared shielding particles and the dispersant described above to form a dispersion liquid, and for example, various organic compounds can be used.

[0078] As the dispersion medium, for example, one or more selected from aromatic hydrocarbons such as toluene and xylene can be suitably used.

[0079] In the dispersion preparation step, the dispersion can be prepared by mixing the infrared-shielding particles, the dispersant, and the dispersion medium. However, in order to reduce the dispersed particle size of the infrared-shielding particles and to disperse them uniformly in the dispersion, it is preferable to perform a pulverization treatment of the infrared-shielding particles at the same time as mixing.

[0080] The mixing means used when mixing and pulverizing the infrared shielding particles, dispersant, and dispersion medium is not particularly limited, and may be one or more selected from, for example, a bead mill, a ball mill, a sand mill, a paint shaker, an ultrasonic homogenizer, etc. In particular, it is more preferable to use a media agitation mill such as a bead mill, a ball mill, a sand mill, or a paint shaker that uses a medium such as beads, balls, or Ottawa sand as the mixing means. This is because the use of a media agitation mill allows the infrared shielding particles to have a desired dispersed particle size in a particularly short time, and is preferable from the viewpoints of productivity and suppressing the inclusion of impurities. (1-2) Dispersion medium reduction process In the dispersion medium reducing step, the dispersion medium can be evaporated and dried from the dispersion liquid.

[0081] In the dispersion medium reducing step, it is preferable that the dispersion medium is sufficiently evaporated from the dispersion liquid so that the infrared shielding particles can be recovered.

[0082] The specific means for evaporating the dispersion medium is not particularly limited, but for example, a dryer such as an oven, an evaporator, a vacuum fluidized dryer such as a vacuum crusher, or a spray dryer such as a spray dryer can be used.

[0083] The degree to which the dispersion medium is evaporated is not particularly limited, but it is preferable that the content ratio of the dispersion medium be reduced sufficiently so that powdery infrared shielding particles are obtained after the dispersion medium reduction step.

[0084] By evaporating the dispersion medium, the dispersant is disposed around the infrared shielding particles, and infrared shielding particles having hydrophobic surfaces can be obtained. This makes it possible to enhance adhesion between the hydrophobically treated infrared shielding particles and the coating resin obtained by polymerizing the coating resin raw material, and makes it possible to dispose the coating resin on at least a part of the surface of the infrared shielding particles by a polymerization step or the like, which will be described later. (1-3) Raw material mixture preparation process In the raw material mixture preparation step, the infrared shielding particles recovered after the dispersion medium reduction step, the coating resin raw material, the organic solvent, the emulsifier, water, and the polymerization initiator are mixed together to prepare the raw material mixture.

[0085] The infrared-shielding particles recovered after the dispersion medium reduction step may have the dispersant supplied in the dispersion liquid preparation step attached to their surfaces, forming dispersant-containing infrared-shielding particles. Therefore, when the dispersant is attached to the infrared-shielding particles in this way, the dispersant-containing infrared-shielding particles recovered after the dispersion medium reduction step are used as the infrared-shielding particles in the raw material mixture preparation step.

[0086] Hereinafter, each material other than the infrared shielding particles used in the raw material mixture preparation step will be described. (a) Coating resin raw material The coating resin raw material is polymerized in a polymerization step described below to become a coating resin disposed on at least a part of the surface of the infrared shielding particle, and can form, for example, a resin capsule. Therefore, as the coating resin raw material, various monomers that can form a desired coating resin by polymerization can be selected.

[0087] The resin for coating after polymerization is not particularly limited, and may be, for example, one or more resins selected from thermoplastic resins, thermosetting resins, photocurable resins, and the like.

[0088] Examples of thermoplastic resins include polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, polyamide resin, vinyl chloride resin, olefin resin, fluororesin, polyvinyl acetate resin, thermoplastic polyurethane resin, acrylonitrile butadiene styrene resin, polyvinyl acetal resin, acrylonitrile-styrene copolymer resin, ethylene-vinyl acetate copolymer resin, and the like.

[0089] Examples of thermosetting resins include phenolic resins, epoxy resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, thermosetting polyurethane resins, polyimide resins, and silicone resins.

[0090] The photocurable resin may be, for example, a resin that is cured by irradiation with ultraviolet light, visible light, or near-infrared light.

[0091] The coating resin preferably contains one or more selected from polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, polyamide resin, vinyl chloride resin, olefin resin, fluororesin, polyvinyl acetate resin, polyurethane resin, acrylonitrile butadiene styrene resin, polyvinyl acetal resin, acrylonitrile-styrene copolymer resin, ethylene-vinyl acetate copolymer resin, phenolic resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyimide resin, and silicone resin. The polyurethane resin may be either a thermoplastic polyurethane or a thermosetting polyurethane.

[0092] Furthermore, a photocurable resin can also be suitably used as the coating resin, and as the photocurable resin, a resin that is cured by irradiation with any of ultraviolet light, visible light, and infrared light can be suitably used, as described above.

[0093] Among these, the coating resin is preferably a resin to which the mini-emulsion polymerization method can be applied, and more preferably contains, for example, a polystyrene resin. When the coating resin is polystyrene, styrene can be used as the coating resin raw material.

[0094] Furthermore, polyfunctional vinyl monomers such as divinylbenzene and ethylene glycol dimethacrylate can also be added as crosslinking agents. (b) Organic solvent The organic solvent has the effect of stabilizing the oil droplets, and can also be called a stabilizer, an additive, or the like.

[0095] The organic solvent is not particularly limited, and any water-insoluble organic solvent may be used. Among them, low-molecular-weight organic solvents are preferred, and examples thereof include one or more selected from long-chain alkyl compounds such as hexadecane, alkyl methacrylates with long alkyl chains such as dodecyl methacrylate and stearyl methacrylate, higher alcohols such as cetyl alcohol, and oils such as olive oil.

[0096] As the organic solvent, particularly, a long-chain alkyl compound is more preferable, and hexadecane is even more preferable. (c) Emulsifier The emulsifier, i.e., surfactant, may be any of cationic, anionic, nonionic, etc., and is not particularly limited.

[0097] Examples of cationic emulsifiers include alkylamine salts and quaternary ammonium salts.

[0098] Examples of anionic emulsifiers include acid salts and ester salts.

[0099] Examples of nonionic emulsifiers include various esters, various ethers, various ester ethers, alkanolamides, and the like.

[0100] As the emulsifier, for example, one or more types selected from the above-mentioned materials can be used.

[0101] Among these, it is particularly preferable to use a cationic emulsifier, that is, a surfactant exhibiting cationic properties, from the viewpoint of easily forming organic-inorganic hybrid infrared-shielding particles.

[0102] In particular, when an amine compound is used as a dispersant, it is preferable to use one or more cationic emulsifiers selected from dodecyltrimethylammonium chloride (DTAC), cetyltrimethylammonium chloride (CTAC), etc.

[0103] Furthermore, when an amine compound is used as a dispersant, it may be difficult to form organic-inorganic hybrid infrared-shielding particles if an anionic emulsifier such as sodium dodecyl sulfate (SDS) is used. When preparing the raw material mixture, the emulsifier can be added as an aqueous solution, for example, by adding it to water that is added at the same time. In this case, it is preferable to add the emulsifier as an aqueous solution adjusted to a concentration of 10 to 1,000 times, more preferably 10 to 500 times, even more preferably 10 to 300 times, and particularly preferably 10 to 150 times the critical micelle concentration (CMC).

[0104] According to the studies of the present inventors, by adding a predetermined proportion of an emulsifier to the coating resin raw material to be added and thoroughly stirring the mixture in accordance with the amount of emulsifier added, it is possible to achieve an infrared-shielding particle content of 15% by mass or more in the resulting organic-inorganic hybrid infrared-shielding particles. That is, by selecting the proportion of emulsifier added to the coating resin raw material and the stirring conditions, it is possible to perform resin coating or encapsulation even when the infrared-shielding particle content is 15% by mass or more. However, these conditions vary depending on the type of emulsifier, etc., and are not particularly limited. It is preferable to conduct preliminary tests and select appropriate conditions. (d) Polymerization initiator The polymerization initiator is not particularly limited and may be one or more selected from various polymerization initiators such as radical polymerization initiators and ionic polymerization initiators.

[0105] Examples of radical polymerization initiators include azo compounds, dihalogens, organic peroxides, etc. Also included are redox initiators that combine an oxidizing agent and a reducing agent, such as hydrogen peroxide and iron (II) salts, or persulfates and sodium hydrogen sulfite.

[0106] Examples of the ionic polymerization initiator include nucleophiles such as n-butyllithium, and electrophiles such as protonic acids, Lewis acids, halogen molecules, and carbocations.

[0107] As the polymerization initiator, for example, one or more selected from 2,2'-azobisisobutyronitrile (AIBN), potassium peroxodisulfate (KPS), 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V-50), 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamidine) (VA-086), and the like can be suitably used.

[0108] When preparing the raw material mixture, the polymerization initiator can be added to the organic phase or the aqueous phase depending on the type of initiator. For example, when 2,2'-azobisisobutyronitrile (AIBN) is used, it can be added to the organic phase, and when potassium peroxodisulfate (KPS) or 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V-50) is used, it can be added to the aqueous phase.

[0109] In the raw material mixture preparation step, the infrared shielding particles recovered after the dispersion medium reduction step, the coating resin raw material, an organic solvent, an emulsifier, water, and a polymerization initiator are mixed to prepare the raw material mixture. Therefore, the preparation procedure of the raw material mixture is not particularly limited, but for example, a mixed liquid containing an emulsifier can be prepared in advance as the aqueous phase. Also, a mixed liquid can be prepared in advance as the organic phase, in which the coating resin raw material and the infrared shielding particles recovered after the dispersion medium reduction step are dispersed in an organic solvent.

[0110] The polymerization initiator may be added to the aqueous phase or the organic phase depending on the type of polymerization initiator used, as described above.

[0111] Then, the organic phase is added to the aqueous phase and mixed to prepare a raw material mixture.

[0112] In order to distribute the coating resin more uniformly on the surfaces of the infrared-shielding particles, it is preferable to thoroughly stir the mixture after adding the organic phase to the aqueous phase. That is, it is preferable that the raw material mixture preparation step further includes a stirring step of stirring the obtained mixture, in addition to the mixing step of mixing the infrared-shielding particles recovered after the dispersion medium reduction step, the coating resin raw material, the organic solvent, the emulsifier, water, and the polymerization initiator.

[0113] In the stirring step, stirring can be performed using, for example, a stirrer. When the stirring step is performed, the degree of stirring is not particularly limited, but it is preferable to stir so that, for example, oil-in-water droplets in which the infrared-shielding particles encapsulated in the coating resin raw material are dispersed in the aqueous phase are formed.

[0114] The amount of polymerization initiator added is not particularly limited and can be selected arbitrarily. The amount of polymerization initiator added can be selected depending on the type of coating resin raw material and polymerization initiator, the size of the oil droplets in the mini-emulsion, the ratio of the coating resin raw material to the infrared-shielding particles, and other factors. For example, it is preferable to add the polymerization initiator in an amount of 0.01 mol% to 1000 mol% of the coating resin raw material, as this makes it easier to obtain organic-inorganic hybrid infrared-absorbing particles in which the infrared-shielding particles are sufficiently coated with the coating resin. The amount of polymerization initiator added is more preferably 0.1 mol% to 200 mol%, and even more preferably 0.2 mol% to 100 mol% of the coating resin raw material. (1-4) Stirring process In the stirring step, the raw material mixture obtained in the raw material mixture preparation step can be stirred while being cooled.

[0115] The degree of stirring in the stirring step is not particularly limited and can be selected as desired. For example, it is preferable to stir the mixture so that the size of the oil-in-water droplets, which is an O / W type emulsion in which the infrared-absorbing particles encapsulated in the coating resin raw material are dispersed in the aqueous phase, becomes a mini-emulsion with a predetermined size.

[0116] The miniemulsion can be obtained by adding a substance that is practically insoluble in water, i.e., a hydrophobe, to the organic phase and applying a strong shear force. Examples of the hydrophobe include the organic solvents already mentioned in the raw material mixture preparation step.

[0117] In the stirring step, it is preferable to stir the obtained mini-emulsion so that it has particle size characteristics corresponding to the desired organic-inorganic hybrid infrared-shielding particles.

[0118] In the stirring step, specifically, stirring is preferably performed so that the miniemulsion has a single peak in the particle size distribution based on scattering intensity measured by dynamic light scattering. That is, in the stirring step, the particle size distribution of the resulting miniemulsion preferably does not have two or more peaks. When the particle size distribution of the miniemulsion obtained in the stirring step is represented by a single peak, the organic-inorganic hybrid infrared-shielding particles produced using the miniemulsion have excellent dispersibility in various media, such as dispersion media. Therefore, the organic-inorganic hybrid infrared-shielding particles can be easily used to form infrared-shielding dispersions, infrared-shielding dispersions, infrared-shielding fibers, infrared-shielding structures, clothing, and the like. Furthermore, the infrared-shielding properties and infrared-shielding effects of the resulting infrared-shielding dispersions, infrared-shielding dispersions, infrared-shielding fibers, infrared-shielding structures, clothing, and the like can be particularly enhanced.

[0119] In the stirring step, the specific conditions for obtaining the desired mini-emulsion are not particularly limited. For example, depending on the type and amount of emulsifier, etc., stirring conditions such as the capacity of the stirring tank, the presence or absence of a baffle, the stirring power, and the type of stirring means used can be selected so that an appropriate stirring force can be applied to the raw material mixture. The stirring step can also be carried out multiple times while changing the stirring conditions. It is also preferable to conduct a preliminary test for the stirring step and select appropriate conditions.

[0120] In the stirring step, it is preferable to stir the raw material mixture while cooling it as described above, because by cooling the raw material mixture, it is possible to form a mini-emulsion while suppressing the progress of the polymerization reaction.

[0121] The mini-emulsion obtained in the stirring step desirably has a median diameter D50 of 1 μm or less in the particle size distribution based on scattering intensity measured by dynamic light scattering. The median diameter of the mini-emulsion is maintained in the polymerization step and becomes the median diameter of the organic-inorganic hybrid infrared-shielding particles. The median diameter of the organic-inorganic hybrid infrared-shielding particles affects the feel during the production of infrared-shielding fibers and when touching the resulting infrared-shielding fiber structure. For this reason, it is preferable to select the median diameter of the organic-inorganic hybrid infrared-shielding particles depending on the feel, etc., required for the infrared-shielding fiber structure.

[0122] The median diameter of the miniemulsion obtained in the stirring step is more preferably 800 nm or less, and even more preferably 500 nm or less. The lower limit of the median diameter of the miniemulsion obtained in the stirring step is not particularly limited, but from the viewpoint of containing a sufficient amount of infrared absorbing particles, it is preferably 30 nm or more, more preferably 50 nm or more, even more preferably 100 nm or more, and particularly preferably 150 nm or more.

[0123] The degree to which the raw material mixture is cooled is not particularly limited, but it is preferable to cool it using a refrigerant at 0° C. or below, for example, in an ice bath. (1-5) Polymerization process In the polymerization step, a deoxidation treatment for reducing the amount of oxygen in the raw material mixture can be carried out, and then the polymerization reaction of the coating resin raw material can be carried out.

[0124] In the polymerization step, the coating resin raw material is polymerized to dispose the coating resin on at least a part of the surface of the infrared shielding particle. In this case, it is preferable to obtain organic-inorganic hybrid infrared absorbing particles in which the infrared absorbing particles are disposed in resin capsules by the polymerization step.

[0125] The conditions for the polymerization step are not particularly limited, but a deoxidation treatment for reducing the amount of oxygen in the raw material mixture can be performed before the start of polymerization. The specific method for the deoxidation treatment is not particularly limited, but examples include a method of irradiating the raw material mixture with ultrasonic waves and a method of blowing an inert gas into the raw material mixture.

[0126] The specific conditions for carrying out the polymerization reaction are not particularly limited and can be arbitrarily selected depending on the coating resin raw material added to the raw material mixture, etc. In the polymerization step, the polymerization reaction can be advanced by, for example, heating the raw material mixture or irradiating it with light of a predetermined wavelength.

[0127] According to the method for producing organic-inorganic hybrid infrared-shielding particles described above, it is possible to obtain organic-inorganic hybrid infrared-shielding particles by disposing an organic material such as a resin on at least a portion of the surface of the infrared-shielding particles, which has been difficult to do in the past. Therefore, even when exposed to a high-temperature environment containing a chemical such as an acid or alkali, the infrared-shielding particles can be prevented from coming into direct contact with the chemical component such as an acid or alkali, and the infrared-shielding particles have excellent chemical resistance and can be prevented from decreasing in infrared-shielding properties and infrared-transmission preventing effect.

[0128] Furthermore, according to the method for producing organic-inorganic hybrid infrared-shielding particles of the present embodiment, it is possible to produce organic-inorganic hybrid infrared-shielding particles in which the content of the infrared-shielding particles can be increased to a high concentration of up to 55 mass%, which has been particularly difficult in the past. As a result, it is possible to obtain organic-inorganic hybrid infrared-shielding particles that are excellent not only in chemical resistance but also in infrared-shielding properties and infrared-transmission prevention effect. (2) Organic-inorganic hybrid infrared shielding particles The organic-inorganic hybrid infrared-shielding particles of this embodiment preferably have infrared-shielding particles and a coating resin that covers at least a portion of the surface of the infrared-shielding particles. It is more preferable that the coating resin forms a resin capsule, and the infrared-shielding particles are disposed in the resin capsule. That is, it is more preferable that the entire surface of the infrared-shielding particles is covered with the coating resin. The organic-inorganic hybrid infrared-shielding particles may have, for example, a spherical shape and a circular cross section. The spherical shape and circular shape do not have a strict geometrical meaning, and for example, the particles may be partially deformed.

[0129] The organic-inorganic hybrid infrared shielding particles can have a high concentration of infrared shielding particles, up to 55% by mass.

[0130] As mentioned above, infrared-shielding particles are typically made of inorganic materials, and it has been difficult to dispose an organic material such as a resin on at least a portion of their surface. However, the inventors of the present invention conducted research and discovered that by disposing a resin on at least a portion of the surface of infrared-shielding particles, organic-inorganic hybrid infrared-shielding particles with a high content of infrared-shielding particles can be produced. By disposing a coating resin on at least a portion of the surface of the infrared-shielding particles, even if the organic-inorganic hybrid infrared-shielding particles are exposed to a high-temperature environment containing chemicals such as acids or alkalis, the infrared-shielding particles can be prevented from coming into direct contact with chemical components such as acids or alkalis. Therefore, chemical resistance can be imparted by forming the organic-inorganic hybrid infrared-shielding particles. As described above, by disposing the infrared-shielding particles in a resin capsule, chemical resistance can be particularly enhanced.

[0131]

[0013] Furthermore, as described above, it is difficult to arrange an organic material such as a resin on the surface of infrared-shielding particles, and no study has been conducted on increasing the content ratio of the infrared-shielding particles in particular. Therefore, the inventors of the present invention conducted studies and found that by using organic-inorganic hybrid infrared-shielding particles with a content ratio of the infrared-shielding particles of a predetermined amount or more, an infrared-shielding material can be obtained that has chemical resistance, infrared-shielding properties, and an infrared-transmission prevention effect, and have completed the present invention.

[0132] In the organic-inorganic hybrid infrared shielding particles of this embodiment, a coating resin is disposed on at least a part of the surface of the infrared shielding particle.

[0133] In particular, the organic-inorganic hybrid infrared-shielding particles of this embodiment preferably have a configuration in which the infrared-shielding particles are disposed in a resin capsule formed by a coating resin. A plurality of infrared-shielding particles may be disposed in one resin capsule, or only one may be disposed in one resin capsule. The infrared-shielding particles may be unevenly distributed in the resin capsule, but are preferably dispersed.

[0134] It is sufficient that the infrared-shielding particles are at least partially coated with the resin capsule, and some of the infrared-shielding particles may be exposed on the outer surface from the resin capsule. However, it is preferable that the infrared-shielding particles are completely coated with the resin capsule, i.e., encapsulated in the resin capsule. This is because, when the infrared-shielding particles are completely coated with the resin capsule, even when the organic-inorganic hybrid infrared-shielding particles come into contact with various chemical components, the infrared-shielding particles can be more reliably prevented from coming into contact with the chemicals, thereby particularly improving chemical resistance.

[0135] The organic-inorganic hybrid infrared shielding particles of the present embodiment are not limited to the above-described form. For example, the shape, size, arrangement, and distribution of the infrared shielding particles, and the shape and arrangement of the coating resin are not limited to the above-described form. (2-1) Components of the organic-inorganic hybrid infrared shielding particles The components of the organic-inorganic hybrid infrared shielding particles of this embodiment will be described below. (a) Coating resin The material of the coating resin is not particularly limited, but may contain, for example, a resin component. The resin component may be selected depending on the optical properties required for the organic-inorganic hybrid infrared-shielding particles, and is not particularly limited. The coating resin may be, as the resin component, one or more resins selected from, for example, thermoplastic resins, thermosetting resins, photocurable resins, etc.

[0136] Examples of thermoplastic resins include polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, polyamide resin, vinyl chloride resin, olefin resin, fluororesin, polyvinyl acetate resin, thermoplastic polyurethane resin, acrylonitrile butadiene styrene resin, polyvinyl acetal resin, acrylonitrile-styrene copolymer resin, ethylene-vinyl acetate copolymer resin, and the like.

[0137] Examples of thermosetting resins include phenolic resins, epoxy resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, thermosetting polyurethane resins, polyimide resins, and silicone resins.

[0138] The photocurable resin may be, for example, a resin that is cured by irradiation with ultraviolet light, visible light, or infrared light.

[0139] The coating resin preferably contains, as a resin component, one or more resins selected from polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, polyamide resin, vinyl chloride resin, olefin resin, fluororesin, polyvinyl acetate resin, polyurethane resin, acrylonitrile butadiene styrene resin, polyvinyl acetal resin, acrylonitrile-styrene copolymer resin, ethylene-vinyl acetate copolymer resin, phenolic resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyimide resin, and silicone resin. The polyurethane resin may be either a thermoplastic polyurethane resin or a thermosetting polyurethane resin. The resin component of the coating resin may also be composed of one or more resins selected from the above group of resins.

[0140] Photocurable resins can also be suitably used as the resin component, and as mentioned above, resins that are cured by irradiation with any of ultraviolet, visible, and infrared light can be suitably used as the photocurable resin. Therefore, the coating resin can also contain a photocurable resin as the resin component, and the photocurable resin preferably contains a resin that is cured by irradiation with any of ultraviolet, visible, and infrared light. The resin component contained in the coating resin can also be composed of the above-mentioned photocurable resin.

[0141] The coating resin may be composed of only the resin component, but may also contain, for example, an emulsifier, a polymerization initiator, and the like that are added during the production process. (b) Infrared shielding particles The infrared-shielding particles have already been described in the method for producing organic-inorganic hybrid infrared-shielding particles, and therefore further description thereof will be omitted. For the organic-inorganic hybrid infrared-shielding particles, it is preferable to use infrared-shielding particles containing, for example, various materials having free electrons, and it is more preferable to use infrared-shielding particles containing various inorganic materials having free electrons.

[0142] The infrared shielding particles may contain various compounds having infrared shielding properties, but preferably contain at least one selected from tungsten oxides having oxygen deficiency and composite tungsten oxides. In particular, the infrared shielding particles are preferably those having a general formula M x W y O z (Element M is one or more elements selected from H, He, 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, Be, Hf, Os, Bi, and I; 0.001≦x / y≦1, 2.0≦z / y<4.0) is preferred.

[0143] The organic-inorganic hybrid infrared-shielding particles described above have a coating resin, which is an organic material, disposed on at least a portion of the surface of the infrared-absorbing particles, which has been difficult to achieve in the past. Therefore, even when exposed to a high-temperature chemical environment containing an acid, alkali, or the like, the infrared-shielding particles are prevented from coming into direct contact with the chemical component, such as an acid or alkali, and therefore excellent chemical resistance is achieved, and a deterioration in the infrared-shielding properties can be prevented. Furthermore, infrared-absorbing fibers using the organic-inorganic hybrid infrared-shielding particles can also be provided with chemical resistance. (2-2) Content of infrared shielding particles in organic-inorganic hybrid infrared shielding particles The content ratio of the infrared-shielding particles in the organic-inorganic hybrid infrared-shielding particles is not particularly limited. For example, in the infrared-shielding fiber structure of the present embodiment using the organic-inorganic hybrid infrared-shielding particles, the content of the infrared-shielding particles per unit area is 0.10 g / m. 2 More than 4.5g / m 2 It is sufficient if the configuration is as follows.

[0144] In the organic-inorganic hybrid infrared shielding particles, for example, the content of the infrared shielding particles is preferably 2% by mass or more, and more preferably 3% by mass or more.

[0145] However, if the content of the infrared-shielding particles in the organic-inorganic hybrid infrared-shielding particles is too high, the degree to which the infrared-shielding particles are covered with the coating resin may decrease. Therefore, the content of the infrared-shielding particles in the organic-inorganic hybrid infrared-shielding particles is preferably 55% by mass or less, and more preferably 50% by mass or less. (2-3) Particle size of organic-inorganic hybrid infrared shielding particles In the particle size distribution of the organic-inorganic hybrid infrared shielding particles based on scattering intensity measured by a dynamic light scattering method, it is desirable that the median diameter D50 is 1 μm or less.

[0146] The D50 is more preferably 800 nm or less, and even more preferably 500 nm or less. Although the lower limit of D50 is not particularly limited, from the viewpoint of incorporating a sufficient amount of infrared-shielding particles, it is preferably 30 nm or more, more preferably 50 nm or more, and even more preferably 100 nm or more.

[0147] If the D50 of the organic-inorganic hybrid infrared-shielding particles is 1 μm or less, it is possible to avoid deterioration in spinnability such as clogging of the spinneret (nozzle) and thread breakage when spinning an infrared-shielding fiber containing the organic-inorganic hybrid infrared-shielding particles therein. Even if spinning can be carried out, problems such as thread breakage may occur in the drawing step, and it may be difficult to uniformly mix and disperse the particles in the spinning raw material. From this viewpoint, it is preferable that the D50 is 1 μm or less.

[0148] Furthermore, when organic-inorganic hybrid infrared-shielding particles are attached to the surface of a fiber to form an infrared-shielding fiber, if the D50 of the organic-inorganic hybrid infrared-shielding particles is 1 μm or less, the particles will not cause discomfort when the fiber comes into contact with the human body. The same applies to the case where an infrared-shielding fiber structure is formed by attaching organic-inorganic hybrid infrared-shielding particles to a fabric such as a woven fabric or knitted fabric to form an infrared-shielding fiber having organic-inorganic hybrid infrared-shielding particles attached to the surface of the fiber. (3) Infrared shielding textile structure The infrared-shielding fiber structure of this embodiment has a fabric containing organic-inorganic hybrid infrared-shielding particles and fibers.

[0149] The content of infrared shielding particles per unit area is set to 0.10 g / m 2 More than 4.5g / m 2 It can be as follows: (3-1) Infrared shielding fiber The fabric may include an infrared-shielding fiber containing organic-inorganic hybrid infrared-shielding particles and fibers. The fabric may be a woven or knitted fabric of the infrared-shielding fiber, or may be a nonwoven fabric. Note that the fabric may also contain fibers that do not have organic-inorganic hybrid infrared-shielding particles disposed therein, in addition to the infrared-shielding fiber.

[0150] Fig. 1 shows a schematic diagram of the fibers included in the infrared-shielding fiber structure of this embodiment. Fig. 1 shows a schematic cross-sectional view of a fiber 11 taken along a plane passing through a central axis CA. As shown in Fig. 1, the organic-inorganic hybrid infrared-shielding particles 12 can be disposed at one or more positions selected from the surface 11A and the interior 11B of the fiber 11. As described above, the fiber 11 having the organic-inorganic hybrid infrared-shielding particles 12 disposed at one or more positions selected from the surface 11A and the interior can also be referred to as an infrared-shielding fiber 10.

[0151] 1 is a schematic diagram showing an example in which the organic-inorganic hybrid infrared-shielding particles 12 are arranged on both the surface 11A and the interior 11B of the fiber 11, but the present invention is not limited to this form. The organic-inorganic hybrid infrared-shielding particles 12 may be arranged on only one of the surface 11A and the interior 11B of the fiber 11. Furthermore, while the organic-inorganic hybrid infrared-shielding particles 12 are depicted as spherical particles in FIG. 1, the shape of the organic-inorganic hybrid infrared-shielding particles 12 is not limited to this form and may have any shape. (3-2) Resin cured film 2, the infrared-shielding fiber structure 20 of this embodiment may further include, in addition to a fabric 21 containing organic-inorganic hybrid infrared-shielding particles and fibers, a cured resin film 22 disposed at one or more positions selected from a surface 21A and an interior 21B of the fabric 21. Note that FIG. 2 is a cross-sectional view of the fabric 21 and the cured resin film 22 taken along the lamination direction.

[0152] 2 shows an example in which a continuous cured resin film 22 is disposed over the entire first surface 211 of the fabric 21, but the present invention is not limited to this. The cured resin film 22 may be disposed so as to cover only a portion of the first surface 211 of the fabric 21. Furthermore, the cured resin film 22 may be provided not only on the first surface 211 of the fabric 21 but also on the second surface 212, etc.

[0153] The cured resin film 22 may contain organic-inorganic hybrid infrared shielding particles, and the cured resin film 22 may also have an infrared shielding function.

[0154] The organic-inorganic hybrid infrared-shielding particles used in the cured resin film 22 can be produced by the same production method as the organic-inorganic hybrid infrared-shielding particles used in the infrared-shielding fiber, for example. Therefore, the description already given for the organic-inorganic hybrid infrared-shielding particles used in the cured resin film 22 will be omitted. Note that the organic-inorganic hybrid infrared-shielding particles used in the infrared-shielding fiber and the organic-inorganic hybrid infrared-shielding particles used in the cured resin film 22 may be the same as or different from each other in terms of composition, particle size, and other physical properties.

[0155] The cured resin film 22 can be formed by applying a coating liquid containing organic-inorganic hybrid infrared-shielding particles to the fabric 21, and then drying and curing the applied film. By the above-mentioned operation, the cured resin film 22 can be disposed at one or more positions selected from the surface and the interior of the fabric 21, which may be, for example, a woven fabric, knitted fabric, or nonwoven fabric made of infrared-shielding fibers.

[0156] Alternatively, the base material 21 may not contain the organic-inorganic hybrid infrared-shielding particles, and the cured resin film 22 may contain the organic-inorganic hybrid infrared-shielding particles.

[0157] A coating liquid that can be suitably used when producing a cured resin film will be described below.

[0158] The coating liquid can be prepared by mixing the organic-inorganic hybrid infrared shielding particles, one or more binder resins selected from acrylic, epoxy, urethane, polyester, etc., and a solvent such as water or an organic solvent. When stirring the raw materials for the coating liquid, known methods such as a media stirring mill, a ball mill, a sand mill, a planetary mixer, and ultrasonic dispersion can be suitably used.

[0159] The coating liquid can be applied to fabric 21, including woven fabric, knitted fabric, nonwoven fabric, etc., by known printing methods such as screen printing, letterpress printing, intaglio printing, and inkjet printing, or known coating methods using an applicator or coater.

[0160] The coating film obtained by applying the coating liquid is dried and cured by a known method such as heat drying to form a cured resin film.

[0161] Microscopic observation of the fibers constituting the infrared-shielding fiber structure 20 provided with the cured resin film 22 may reveal that organic-inorganic hybrid infrared-shielding particles are attached to the surfaces of the constituent fibers. Therefore, the infrared-shielding fiber is similar to the infrared-shielding fiber obtained by the method (d) described later in the infrared-shielding fiber manufacturing method, in which organic-inorganic hybrid infrared-shielding particles are attached to the surfaces of fibers obtained by prior spinning using a binder or the like. Therefore, by arranging the cured resin film 22 on the surface of the fabric 21, the organic-inorganic hybrid infrared-shielding particles can be arranged on the surfaces of the fibers of the fabric 21, even if the fabric 21 did not contain organic-inorganic hybrid infrared-shielding particles before the cured resin film 22 was arranged.

[0162] That is, the infrared shielding fiber structure 20 of this embodiment can also be produced by forming the cured resin film 22 on a fiber fabric 21 that does not contain organic-inorganic hybrid infrared shielding particles.

[0163] The content of infrared shielding particles per unit area of ​​the infrared shielding fiber structure is 0.10 g / m 2 More than 4.5g / m 2 or less, preferably 0.15 g / m 2More than 4.5g / m 2 More preferably, it is 0.20 g / m or less. 2 More than 4.5g / m 2 The content of infrared-shielding particles per unit area of ​​the infrared-shielding fiber structure is 0.10 g / m or less. 2 If this is the case, the average reflectance of the infrared-shielding fiber structure in the infrared region at wavelengths of 800 nm or more and 1300 nm or less can be 65% or less. If the average reflectance of the infrared-shielding fiber structure is 65% or less, it is possible to prevent infrared surreptitious photography (viewing with an imaging device such as a CCD camera) in clothing using woven or knitted fabrics that are infrared-shielding fiber structures. It is more preferable that the average reflectance of the infrared-shielding fiber structure in the infrared region at wavelengths of 800 nm or more and 1300 nm or less (hereinafter also referred to as the "specific infrared wavelength range") is 60% or less, and even more preferably 55% or less.

[0164] In order to make the average reflectance of the infrared-shielding fiber structure in a specific infrared wavelength range 60% or less, the content of the infrared-shielding particles per unit area of ​​the infrared-shielding fiber structure must be 0.15 g / m 2 In order to make the average reflectance of the infrared-shielding fiber structure in a specific infrared wavelength range 55% or less, the content of the infrared-shielding particles can be set to 0.20 g / m or more. 2 It can be more than that.

[0165] On the other hand, the content of infrared shielding particles per unit area of ​​the infrared shielding fiber structure is 4.5 g / m 2 If the average reflectance exceeds 0.07%, the effect of preventing surreptitious photography by infrared rays will not be further improved even if the average reflectance is adjusted to a lower value. Therefore, the upper limit of the content of infrared shielding particles per unit area of ​​the infrared shielding fiber structure is preferably 3.5 g / m. 2 The content of infrared shielding particles per unit area is 3.5 g / m or less. 2If the average reflectance is less than 0.2%, the effect of preventing surreptitious photography by infrared rays will be fully demonstrated. However, if the infrared-shielding fiber structure contains too many infrared-shielding particles per unit area, it may be difficult to dye the infrared-shielding fiber structure with certain colors.

[0166] Furthermore, the average reflectance in a specific infrared wavelength range of a fiber structure that does not contain infrared-shielding particles is 77%, as confirmed in Comparative Example 1, and this reflectance makes it possible to take surreptitious photographs using infrared light (see-through using an imaging device such as a CCD camera).

[0167] In addition, the average reflectance of an infrared-shielding fiber structure in the infrared region is the average value of the reflectance of the infrared-shielding fiber structure measured with a spectrophotometer when the wavelength is increased in 5 nm intervals in the wavelength region of 800 nm or more and 1300 nm or less.

[0168] Here, with regard to a solution to prevent surreptitious photography using infrared rays (viewing using an imaging device such as a CCD camera), this specification will explain that attention is focused on the reflectance of the infrared-shielding fiber structure.

[0169] When we look at an object with our eyes, we can recognize it because the light that hits the object is reflected and our eyes form an image of the object, and the same is true for images captured by a camera.

[0170] In the infrared-shielding fiber structure of this embodiment, the organic-inorganic hybrid infrared-shielding particles that absorb infrared rays are arranged at one or more locations selected from the surface and the interior of the fiber. Therefore, when the infrared-shielding fiber structure is irradiated with light, the infrared-shielding particles absorb the infrared rays, thereby reducing the reflectance in a specific infrared wavelength range. In other words, the reflectance of the infrared rays among the light components irradiated onto the infrared-shielding fiber structure of this embodiment is reduced. As a result, even if an attempt is made to photograph the infrared-shielding fiber structure of this embodiment with an imaging device such as a CCD camera, the image will be unclear due to the reduced reflectance in the specific infrared wavelength range.

[0171] It is known that the wavelength range of widely used CCD sensors is 400 nm or more and 1200 nm or less. The infrared-shielding fiber structure of this embodiment reduces the reflectance of a specific infrared wavelength range (wavelength of 800 nm or more and 1300 nm or less) among the irradiated light components, making it possible to prevent surreptitious photography using infrared rays (see-through by an imaging device such as a CCD camera).

[0172] On the other hand, the infrared-shielding particles used in the infrared-shielding fiber structure of this embodiment absorb only a small amount of light in the visible light range compared to their absorption of light in a specific infrared wavelength range (wavelengths of 800 nm or more and 1300 nm or less). In other words, because the infrared-shielding particles of the present invention absorb only a small amount of light in the visible light range, the infrared-shielding fiber structure can be freely colored by dyeing or the like. Furthermore, when the infrared-shielding fiber structure of this embodiment is used in clothing, the amount of infrared light contained in natural light that reaches human skin can be reduced, thereby reducing damage to the skin. (3-3) Fiber The fibers contained in the infrared shielding fiber structure of this embodiment can be selected from a variety of types depending on the application.

[0173] The infrared-shielding fiber structure of this embodiment may contain, as the fiber, one or more types selected from, for example, synthetic fibers, semi-synthetic fibers, natural fibers, regenerated fibers, and inorganic fibers. Specifically, the fiber may be, for example, one or more types selected from the fiber group consisting of synthetic fibers, semi-synthetic fibers, natural fibers, regenerated fibers, and inorganic fibers, or one or more types selected from blended yarns obtained by blending, doubling, or blending one or more types selected from the above fiber group. Considering the ease with which the organic-inorganic hybrid infrared-shielding particles can be incorporated into the fiber, the fiber preferably contains synthetic fibers, and more preferably is synthetic fibers.

[0174] When the infrared-shielding fiber structure of this embodiment contains synthetic fibers, the specific type of the synthetic fibers is not particularly limited, and the synthetic fibers may be one or more types selected from, for example, polyurethane fibers, polyamide fibers, acrylic fibers, polyester fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, polyether ester fibers, etc.

[0175] Examples of polyamide fibers include one or more types selected from nylon, nylon 6, nylon 66, nylon 11, nylon 610, nylon 612, aromatic nylon, aramid, and the like.

[0176] Examples of acrylic fibers include one or more types selected from polyacrylonitrile, acrylonitrile-vinyl chloride copolymer, modacrylic, and the like.

[0177] Examples of polyester fibers include one or more types selected from polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and the like.

[0178] The polyolefin fiber may be one or more types selected from, for example, polyethylene, polypropylene, polystyrene, and the like.

[0179] Examples of polyvinyl alcohol fibers include vinylon.

[0180] Examples of polyvinylidene chloride fibers include vinylidene.

[0181] Examples of polyvinyl chloride fibers include polyvinyl chloride.

[0182] The polyetherester fiber may be one or more types selected from, for example, Rexe, Success, and the like.

[0183] When the infrared absorbing fiber contains semi-synthetic fibers as fibers, the semi-synthetic fibers preferably contain one or more types selected from, for example, cellulosic fibers, protein-based fibers, chlorinated rubber, hydrochloric rubber, and the like.

[0184] The cellulosic fibers include, for example, one or more types selected from acetate, triacetate, acetate oxide, and the like.

[0185] Examples of protein-based fibers include Promix.

[0186] When the infrared absorbing fiber contains natural fibers as fibers, the natural fibers preferably contain one or more types selected from, for example, plant fibers, animal fibers, mineral fibers, and the like.

[0187] Examples of plant fibers include one or more selected from cotton, kapok, flax, hemp, jute, Manila hemp, sisal, New Zealand hemp, ramie, palm, rush, and wheat straw.

[0188] Examples of animal fibers include one or more types selected from wool such as sheep's wool, goat's hair, mohair, cashmere, alpaca, angora, camel, and vicuna, silk, down, and feathers.

[0189] The mineral fiber may be one or more types selected from, for example, asbestos.

[0190] When the infrared absorbing fiber contains recycled fibers as fibers, the recycled fibers preferably contain one or more types selected from, for example, cellulose-based fibers, protein-based fibers, alginate fibers, rubber fibers, chitin fibers, mannan fibers, etc.

[0191] The cellulosic fibers include, for example, one or more types selected from rayon, viscose rayon, cupro, polynosic, cuprammonium rayon, and the like.

[0192] Examples of protein fibers include one or more types selected from casein fiber, peanut protein fiber, corn protein fiber, soy protein fiber, regenerated silk, and the like.

[0193] When the infrared shielding fiber structure of this embodiment contains inorganic fibers as fibers, the inorganic fibers preferably contain one or more types selected from, for example, metal fibers, carbon fibers, silicate fibers, and the like.

[0194] The metal fiber may be one or more types selected from metal fibers, gold threads, silver threads, heat-resistant alloy fibers, and the like.

[0195] Examples of silicate fibers include one or more types selected from glass fibers, slag fibers, rock fibers, and the like.

[0196] The cross-sectional shape of the fibers in the infrared-shielding fiber structure of this embodiment is not particularly limited, and may be, for example, one or more types selected from circular, triangular, hollow, flat, Y-shaped, star-shaped, core-sheath, etc. The infrared-absorbing fiber structure of this embodiment may also contain fibers of different cross-sectional shapes.

[0197] The organic-inorganic hybrid infrared-absorbing particles can be arranged in one or more selected portions of the interior and surface of the fiber in various ways depending on the cross-sectional shape of the fiber. For example, when the cross-sectional shape of the fiber is a core-sheath type, the organic-inorganic hybrid infrared-absorbing particles may be contained in the core or sheath of the fiber. Furthermore, the shape of the fiber possessed by the infrared-absorbing fiber structure of this embodiment may be either filament (long fiber) or staple (short fiber). (4) Additives The infrared-shielding fiber structure of this embodiment may contain antioxidants, flame retardants, deodorizers, insect repellents, antibacterial agents, ultraviolet absorbers, etc. depending on the purpose, as long as the performance of the contained fiber is not impaired.

[0198] The organic-inorganic hybrid infrared-shielding particles have excellent chemical resistance and water resistance, and can maintain their infrared-shielding properties. Water resistance means that the properties do not change significantly even when the particles come into contact with or are immersed in water. The organic-inorganic hybrid infrared-shielding particles have at least a portion of their surface covered with a coating resin, preventing direct contact of the infrared-shielding particles with water even when immersed in water. Therefore, the infrared-shielding fiber structure of this embodiment, which contains the organic-inorganic hybrid infrared-shielding particles, also has excellent chemical resistance and water resistance and can maintain its infrared-shielding properties, preventing surreptitious infrared photography (viewing with an imaging device such as a CCD camera). The infrared-shielding fiber structure of this embodiment has excellent chemical resistance. For example, even when immersed in a 0.01 mol / L aqueous sodium hydroxide solution maintained at 80°C for 30 minutes, there is almost no change in the infrared reflectance properties.

[0199] Due to the chemical resistance of the organic-inorganic hybrid infrared-shielding particles, the effect of preventing surreptitious infrared photography (viewing by imaging devices such as CCD cameras) is maintained even after washing of clothing containing the infrared-shielding fiber structure of this embodiment. Furthermore, when the infrared-shielding fiber structure of this embodiment is used in swimsuits, the water-resistant organic-inorganic hybrid infrared-shielding particles maintain the effect of preventing surreptitious infrared photography (viewing by imaging devices such as CCD cameras) of the infrared-shielding fiber structure even when the infrared-shielding fiber structure is immersed in water. [Infrared shielding fiber manufacturing method] The method for producing the infrared-shielding fiber contained in the infrared-shielding fiber structure of this embodiment is not particularly limited, and the fiber can be produced by arranging organic-inorganic hybrid infrared-shielding particles in one or more areas selected from the surface and interior of the fiber.

[0200] For example, the infrared shielding fiber of the present embodiment can be produced by any one of the production methods (a) to (d) below.

[0201] (a) A method of directly mixing organic-inorganic hybrid infrared shielding particles into the raw polymer of synthetic fibers and spinning them.

[0202] (b) A method in which a master batch is produced in advance by incorporating a high concentration of organic-inorganic hybrid infrared-shielding particles into a portion of the raw polymer, and this is diluted and adjusted to a predetermined concentration before spinning.

[0203] (c) A method in which the organic-inorganic hybrid infrared-shielding particles are uniformly dispersed in a raw material monomer or oligomer solution to prepare a dispersion in advance, and then the target raw material polymer is synthesized using this dispersion, and the organic-inorganic hybrid infrared-shielding particles are dispersed in the raw material polymer and then spun.

[0204] (d) A method in which organic-inorganic hybrid infrared shielding particles are attached to the surface of fibers obtained by spinning in advance using a binder or the like.

[0205] Here, the above-mentioned manufacturing methods (a) to (d) for incorporating organic-inorganic hybrid infrared-shielding particles into the fibers of the infrared-absorbing fiber of this embodiment will be described with specific examples.

[0206] Method (a): For example, a case where polyester fibers are used as the fibers will be described.

[0207] The organic-inorganic hybrid infrared-shielding particle dispersion is added to polyethylene terephthalate resin pellets, which are a thermoplastic resin, and the mixture is mixed uniformly in a blender. The solvent is then removed. The mixture from which the solvent has been removed is melt-kneaded in a twin-screw extruder to obtain a masterbatch containing the organic-inorganic hybrid infrared-shielding particles. This masterbatch containing the organic-inorganic hybrid infrared-shielding particles is melt-mixed at a temperature near the melting temperature of the resin and spun, for example, according to various known methods.

[0208] In this case, a dispersant can be added to improve the dispersibility of the organic-inorganic hybrid infrared-shielding particles in the polyethylene terephthalate resin. The dispersant is not particularly limited as long as it can disperse the organic-inorganic hybrid infrared-shielding particles in the polyethylene terephthalate resin or in fibers obtained by spinning a masterbatch containing the resin. For example, the dispersant used in the polyethylene terephthalate resin is not particularly limited, and is preferably, for example, a polymer dispersant. More preferably, the dispersant has a main chain selected from polyesters, polyethers, polyacrylics, polyurethanes, polyamines, polystyrenes, and aliphatics, or a main chain in which two or more unit structures selected from polyesters, polyethers, polyacrylics, polyurethanes, polyamines, polystyrenes, and aliphatics are copolymerized.

[0209] Furthermore, the dispersant preferably has one or more functional groups selected from an amine-containing group, a hydroxyl group, a carboxyl group, a carboxyl-containing group, a sulfo group, a phosphate group, or an epoxy group. Polyacrylic dispersants having an amine-containing group as a functional group are particularly preferred. Dispersants having any of the above functional groups adsorb to the surface of the organic-inorganic hybrid infrared-shielding particles, thereby more reliably preventing aggregation of the organic-inorganic hybrid infrared-shielding particles. Therefore, they can be used advantageously because they can disperse the organic-inorganic hybrid infrared-shielding particles more uniformly.

[0210] Examples of such dispersants include Solsperse (registered trademark) 9000, 12000, 17000, 20000, 21000, 24000, 26000, 27000, 28000, 32000, 35100, 54000, and Solsix 250 manufactured by Lubrizol Japan Co., Ltd., and EFKA (registered trademark) 4008, EFKA4009, EFKA4010, EFKA4015, EFKA4046, EFKA4047, EFKA4060, EFKA4080, EFKA7462, EFKA4020, EFKA4050, and E FKA4055, EFKA4585, EFKA4400, EFKA4401, EFKA4402, EFKA4403, EFKA4300, EFKA4320, EFKA4330, EFKA4340, EFKA6220, EFKA6225, EFKA6700, EFKA6780, EFKA6782, EFKA8503, Ajinomoto Fine-Techno Co., Ltd. Ajisper (registered trademark) PB821, Ajisper PB822, Ajisper PB824, Ajisper PB881, Famex L-12, and BYK Japan Co., Ltd. Disper BYK (registered trademark) (hereinafter the same) 101, DisperBYK106, DisperBYK108, DisperBYK116, DisperBYK130, DisperBYK140, DisperBYK142, DisperBYK145, DisperBYK161, DisperBYK162, DisperBYK163, DisperBYK164, DisperBYK166, DisperBYK167, DisperBYK168DisperBYK171, DisperBYK180, DisperBYK182, DisperBYK 2000, DisperBYK2001, DisperBYK2009, DisperBYK2013, DisperBYK2022, DisperBYK2025, DisperBYK2050, DisperBYK2155, DisperBYK2164, BYK350, BYK354, BYK355, BYK356, BYK358, BYK361, BYK381, BYK392, BYK394, BYK300, BYK3441, Disparlon (registered trademark) (hereinafter the same) 1831, Disparlon 1850, Disparlon 1860 manufactured by Kusumoto Chemicals Co., Ltd.Examples of such polyethers include Disparlon DA-400N, Disparlon DA-703-50, Disparlon DA-725, Disparlon DA-705, Disparlon DA-7301, Disparlon DN-900, Disparlon NS-5210, Disparlon NVI-8514L, and TERPLUS (registered trademark) MD1000, D 1180, and D 1130 manufactured by Otsuka Chemical Co., Ltd.

[0211] Method (b): The organic-inorganic hybrid infrared-shielding particle-containing masterbatch can be produced by utilizing a method similar to that in (a). Then, the masterbatch and a masterbatch of polyethylene terephthalate to which the organic-inorganic hybrid infrared-shielding particles are not added are melt-mixed at a desired mixing ratio near the melting temperature of the resin, and spun according to a known method.

[0212] Method (c): For example, a case where urethane fibers are used as the fibers will be described.

[0213] A polymeric diol containing organic-inorganic hybrid infrared shielding particles is reacted with an organic diisocyanate in a twin-screw extruder to synthesize an isocyanate-terminated prepolymer, which is then reacted with a chain extender to produce a polyurethane solution (raw polymer).The polyurethane solution is then spun according to various known methods.

[0214] Method (d): For example, a case where organic-inorganic hybrid infrared shielding particles are attached to the surface of natural fibers will be described.

[0215] First, a treatment liquid is prepared by mixing organic-inorganic hybrid infrared shielding particles, one or more binder resins selected from acrylic, epoxy, urethane, and polyester, and a solvent such as water.

[0216] Next, natural fibers are immersed in the prepared treatment solution, or the natural fibers are impregnated with the prepared treatment solution by padding, printing, spraying, or the like, and then dried. This allows the organic-inorganic hybrid infrared-shielding particles to adhere to the natural fibers. Method (d) can be applied to semi-synthetic fibers, regenerated fibers, inorganic fibers, or blends, doubling, or mixed fibers thereof, in addition to the natural fibers described above.

[0217] When carrying out the methods (a) to (d), the method for dispersing the organic-inorganic hybrid infrared-shielding particles in the dispersion medium is not particularly limited, and any method may be used as long as it can uniformly disperse the organic-inorganic hybrid infrared-shielding particles in the liquid, i.e., the dispersion medium. For example, methods such as a medium stirring mill, a ball mill, a sand mill, and ultrasonic dispersion can be suitably applied.

[0218] The dispersion medium for the organic-inorganic hybrid infrared-shielding particles is not particularly limited and can be selected according to the fibers to be mixed in. The dispersion medium can be, for example, one or more selected from various common organic solvents such as alcohols, ethers, esters, ketones, and aromatic compounds, and water.

[0219] Furthermore, when the organic-inorganic hybrid infrared-shielding particles are attached to or mixed with fibers or the polymer that is the raw material thereof, a dispersion of the organic-inorganic hybrid infrared-shielding particles may be directly mixed with the fibers or the polymer that is the raw material thereof. If necessary, an acid or alkali may be added to the dispersion of the organic-inorganic hybrid infrared-shielding particles to adjust the pH, and various surfactants, coupling agents, etc. may also be added to further improve the dispersion stability of the organic-inorganic hybrid infrared-shielding particles.

[0220] The content of the organic-inorganic hybrid infrared-shielding particles in the infrared-shielding fiber is not particularly limited. For example, the content of the organic-inorganic hybrid infrared-shielding particles in the infrared-absorbing fiber is preferably 0.001% by mass or more and 60% by mass or less. Furthermore, when taking into consideration the weight of the infrared-shielding fiber after the addition of the organic-inorganic hybrid infrared-shielding particles and the raw material cost, the content of the organic-inorganic hybrid infrared-shielding particles in the infrared-shielding fiber is more preferably 0.005% by mass or more and 50% by mass or less.

[0221] When the content of the organic-inorganic hybrid infrared-shielding particles in the infrared-shielding fiber is 0.001% by mass or more, a sufficient infrared-shielding effect can be obtained even if the fabric using the infrared-shielding fiber is thin.

[0222] Furthermore, if the content of the organic-inorganic hybrid infrared-shielding particles in the infrared-shielding fiber is 60% by mass or less, it is possible to avoid a decrease in spinnability due to clogging of the filter or thread breakage during the spinning process, and it is particularly preferable if it is 50% by mass or less. Furthermore, it is preferable because the amount of organic-inorganic hybrid infrared-shielding particles that can be added is small, and the physical properties of the fiber are hardly impaired.

[0223] As described above, the infrared-shielding fiber that can be used in the infrared-shielding fiber structure of this embodiment is capable of shielding infrared rays by containing organic-inorganic hybrid infrared-shielding particles on the surface and inside of the fiber.

[0224] The infrared-shielding fibers are processed into long fibers or short fibers depending on the application, and then spun into woven fabrics or knitted fabrics by known methods to form infrared-shielding fiber structures. The infrared-shielding fibers are also processed by known methods to form nonwoven fabrics, which then become infrared-shielding fiber structures. Of course, the yarns spun from the infrared-shielding fibers (spun yarns) may be colorless or dyed. In addition, infrared-shielding fiber structures such as woven fabrics, knitted fabrics, and nonwoven fabrics may also be dyed partially or entirely.

[0225] The infrared-shielding fiber structure according to the present embodiment described above has high chemical resistance, and therefore its infrared-shielding properties do not change significantly even when exposed to a chemical environment such as high-temperature alkali. Therefore, the infrared-shielding fiber structure according to the present embodiment is particularly suitable for use in clothing worn in direct contact with the skin, such as innerwear, stockings, swimwear, skating wear, leotards, marine sportswear, and fitness wear. By using the infrared-shielding fiber structure according to the present embodiment in various types of clothing, the infrared-shielding properties do not change significantly even after repeated washing, and the fabric can be highly effective in continuously preventing surreptitious infrared photography, something that has been difficult to achieve with conventional methods.

[0226] When the organic material disclosed in Patent Document 1 is used as an infrared absorber, the organic infrared absorber has problems with weather resistance and discoloration over time. In contrast, the infrared-shielding fiber structure of this embodiment can protect the infrared-shielding particles by coating them with a coating resin. The infrared-shielding particles can also contain, for example, inorganic composite tungsten oxide. Therefore, the infrared-shielding fiber structure of this embodiment can improve weather resistance and prevent discoloration over time of infrared-shielding fiber structures such as woven fabrics, knitted fabrics, and nonwoven fabrics.

[0227] In addition, in the case of the anti-camera photography fabric disclosed in Patent Document 2, a thin film of metal or the like is arranged, which causes coloring due to the metal, etc., and there are problems such as a decrease in the degree of freedom in color. Furthermore, in the case of the anti-camera photography fabric disclosed in Patent Document 2, the thin film of metal or the like can sometimes affect the texture and stretchability.

[0228] In contrast, according to the infrared-shielding fiber structure of the present embodiment, by using organic-inorganic hybrid infrared-shielding particles and arranging them on the surface or inside of the fiber, coloring is suppressed more than when a thin film of metal or the like is used, and the impact on the texture, etc. can also be reduced.

[0229] In addition, the content of infrared shielding particles per unit area in the infrared shielding fiber structure is set to 0.10 g / m2 More than 4.5g / m 2 By setting the average reflectance of the infrared-shielding fiber structure to 65% or less in the infrared region (wavelengths of 800 nm or more and 1300 nm or less), the infrared-shielding fiber structure can exhibit a function to prevent surreptitious photography using infrared rays, and this function can be maintained for a long period of time.

[0230] Furthermore, the composite tungsten oxide that can be used for the infrared-shielding particles in the infrared-shielding fiber structure of this embodiment has a higher infrared absorption capacity per unit mass than other inorganic infrared-shielding materials (ITO, ATO, etc.), and sufficient infrared-shielding effect can be obtained with a small content. Therefore, when the infrared-shielding particles contain the composite tungsten oxide, the physical properties of the fiber, etc. are not impaired, and the design freedom of the infrared-shielding fiber structure can be increased. [Example]

[0231] The present invention will be explained below by giving specific examples, but the present invention is not limited to these examples.

[0232] The present invention will be specifically described below with reference to examples, although the present invention is not limited to the following examples.

[0233] The optical properties of the infrared-shielding fiber structures obtained in the examples and comparative examples were measured using a spectrophotometer U-4100 (manufactured by Hitachi, Ltd.). [Example 1] Infrared-shielding fibers and infrared-shielding fiber structures were produced and evaluated according to the following procedures. (1) Manufacturing of organic-inorganic hybrid infrared shielding particles Organic-inorganic hybrid infrared shielding particles for use in infrared absorbing fibers were produced according to the following steps.

[0234] 10.8 g of Cs2CO3 was dissolved in 16.5 g of water, and this was added to 450 g of H2WO and dried in a vacuum dryer while stirring. The resulting dried powder was heated while feeding 2% H2 gas by volume using N2 gas as a carrier, and calcined at 800°C for 0.5 hours, and then calcined at 800°C for 1 hour in an N2 gas atmosphere to obtain infrared shielding particles a. Powder X-ray diffraction revealed hexagonal Cs 0.3 It was WO3. (Dispersion liquid preparation process) As the dispersant, a polymer dispersant, which is a copolymer of styrene and 2-(dimethylamino)ethyl methacrylate, was prepared.

[0235] Toluene was used as the dispersion medium.

[0236] The mixture was then crushed and dispersed for 21 hours in a paint shaker containing 0.3 mm diameter ZrO2 beads. A composite tungsten oxide particle dispersion (Liquid A) was obtained by crushing and dispersing 20 mass% of infrared shielding particles a, 3 mass% of polymer dispersant, and 77 mass% of toluene. (Dispersion medium reduction process) The toluene was removed from the dispersion (liquid A) obtained in the dispersion preparation step using an evaporator, and the infrared-shielding particles were recovered. The recovered infrared-shielding particles A were a dry powder of infrared-shielding particles containing a polymer dispersant.

[0237] The number average particle size of the recovered infrared shielding particles A was measured by TEM observation and was found to be 16 nm.

[0238] The number average particle size was calculated by observing and measuring 100 composite tungsten oxide particles by TEM observation. (Raw material mixture preparation process) An organic phase was prepared by mixing 25.8 g of the dispersant-surface-modified infrared absorbing particles obtained in the dispersion medium reduction step with 60 g of styrene, which is a raw material for the coating resin. In this example, the infrared absorbing particles and other components were added and mixed so that the content (target content) of the infrared absorbing particles in the finally obtained organic-inorganic hybrid infrared absorbing particles was 20 mass%.

[0239] In order to disperse the infrared absorbing particles whose surface had been modified with a dispersant in styrene, the organic phase was mixed and subjected to a dispersion treatment.

[0240] Next, 4.18 g of hexadecane, an organic solvent, was added to this organic phase and further dispersed.

[0241] Separately from the organic phase, 6 g of the emulsifier cetyltrimethylammonium chloride, 600 g of water, and 3.12 g of the polymerization initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride were mixed to form an aqueous phase. When forming the aqueous phase, the emulsifier cetyltrimethylammonium chloride was added to water to achieve a concentration 24 times the critical micelle concentration. The polymerization initiator was added at 2.0 mol% relative to the styrene.

[0242] The organic phase was then added to the aqueous phase to prepare a raw material mixture. The amounts of each component added in the raw material mixture preparation step are summarized in Table 1. (stirring process) The raw material mixture prepared in the raw material mixture preparation step was stirred in an ice bath until the particle size distribution of the resulting emulsion measured by dynamic light scattering showed a single peak, with a D50 of 201 nm.

[0243] After the stirring step, the raw material mixture was subjected to nitrogen bubbling in an ice bath for 15 minutes to perform deoxidation treatment.

[0244] The mixture was then heated at 70°C for 15 hours in a nitrogen atmosphere to promote the polymerization of styrene, yielding an organic-inorganic hybrid infrared-absorbing particle dispersion. Water was then removed to obtain organic-inorganic hybrid infrared-shielding particles A.

[0245] The content of infrared-shielding particles in the organic-inorganic hybrid infrared-shielding particles A obtained in Example 1 was 20% by mass. To calculate the content of infrared-shielding particles in the organic-inorganic hybrid infrared-shielding particles A, the organic-inorganic hybrid infrared-shielding particles A were subjected to TGA (thermogravimetry) and heated until the weight loss became constant to remove the resin component. Then, the concentration of infrared-shielding particles in the obtained organic-inorganic hybrid infrared-shielding particles A was measured. (2) Manufacturing of infrared shielding textile structures The obtained organic-inorganic hybrid infrared shielding particle dispersion liquid and a polyurethane resin as a binder resin were mixed to prepare a coating liquid.

[0246] Specifically, 55 parts by mass of a colorless polyurethane resin solution (16 mass% resin, manufactured by Dainichiseika Chemicals), 45 parts by mass of methyl ethyl ketone (MEK), and 0.4 parts by mass of organic-inorganic hybrid infrared-shielding particles A were mixed in a planetary mixer to prepare coating solution A according to Example 1. The mass ratio of the organic-inorganic hybrid infrared-shielding particles A added when forming the coating solution is shown in the column "Amount of organic-inorganic hybrid infrared-shielding particles added to coating solution" in Table 1. The cured resin film A obtained from a coating film thickness of 200 μm from coating solution A contained 0.13 g / m per unit area. 2 The formulation contains infrared shielding particles.

[0247] The solution was applied to a 350 μm thick polyester knit fabric dyed brown with a cationic dye using a 30 cm wide applicator, and dried in a drying oven at 100° C. for 10 minutes to prepare evaluation sample A according to Example 1.

[0248] Using a spectrophotometer manufactured by Hitachi, Ltd., the reflectance of evaluation sample A was measured at 5 nm intervals in the wavelength range of 800 nm to 1300 nm, and the average reflectance of evaluation sample A in the wavelength range of 800 nm to 1300 nm was 62%. (3) Evaluation of infrared shielding textile structures [Evaluation of infrared transmission prevention] Next, the evaluation of the "prevention of surreptitious photography by infrared (viewing by CCD camera)" of the evaluation sample A of Example 1 was carried out according to the following test method in accordance with the Japan Spinners Inspection Association's Boken standard "BQE A 033" in accordance with steps 1 to 5 below. (Step 1) Place the test (fabric) over the transparency test board (eye chart) and place it on the test table. (Step 2) Using an infrared projector, irradiate the test surface with approximately 7 mW / cm 2 The light is projected at an intensity of . (Step 3) Take a normal photograph of the sample with a digital camera. (Step 4) Photograph the sample through infrared light using an infrared camera. (Step 5) Check the transmitted image and determine whether or not there is transmission.

[0249] The test criteria are as follows: 〇: Cannot be seen through. ×: Can be seen through.

[0250] The above evaluation is the evaluation of infrared transmission prevention property.

[0251] As a result, it was confirmed that the infrared ray transmission prevention property of the evaluation sample A according to Example 1 did not allow transmission of infrared rays. The evaluation results are shown in Table 1. [Evaluation of alkali resistance characteristics] Evaluation sample A of Example 1 was immersed in a 0.01 mol / L aqueous sodium hydroxide solution maintained at 80°C for 30 minutes, then rinsed with pure water to remove the alkali, dried at room temperature, and then evaluated for infrared transmission prevention ability again. The results of the infrared shielding fiber structure of Example 1 for infrared transmission prevention ability evaluation did not change before and after the alkali resistance property test, confirming that it was not visible through the infrared shielding fiber structure.

[0252] That is, it was confirmed that the infrared-shielding fiber structure of Example 1 did not change in the evaluation of its infrared transmission prevention ability before and after the alkaline test. Therefore, it was confirmed that the infrared-shielding particle structure, which is the infrared-shielding clothing obtained in this example, has chemical resistance, particularly alkali resistance. [Example 2] to [Example 5] When producing an infrared-shielding fiber structure, the mass ratio of the organic-inorganic hybrid infrared-shielding particles added to the coating solution was changed to the value shown in Table 1. Except for the above, the coating solution was prepared in the same manner as in Example 1, and an infrared-shielding fiber structure was produced and evaluated in the same manner. [Comparative Example 1] When a polyester knit fabric having a thickness of 350 μm and dyed brown with a cationic dye was evaluated for infrared transmission blocking ability in the same manner as in Example 1, infrared transmission was observed, so evaluation of infrared transmission blocking ability after alkali immersion was not performed. Comparative Example 2 Raw materials were prepared as follows: 23 mass% infrared shielding particles a, 18.4 mass% acrylic polymer dispersant having an amine-containing group (acrylic dispersant with an amine value of 48 mg KOH / g and a decomposition temperature of 250°C), and the remainder MEK. The raw materials were then stirred and mixed using 0.3 mm zirconia beads in a paint shaker (manufactured by Asada Iron Works Co., Ltd.) to prepare an infrared shielding particle dispersion liquid according to Comparative Example 2. The number average particle size of the infrared shielding particles contained in the infrared shielding particle dispersion liquid according to Comparative Example 2 was 20 nm.

[0253] In Comparative Example 2, no organic-inorganic hybrid infrared-shielding particles were used, and the infrared-shielding particle dispersion liquid prepared in Comparative Example 2 was used. That is, in Comparative Example 2, the infrared-shielding particles were not coated with a coating resin. 55 parts by mass of a colorless polyurethane resin solution (resin 16% by mass, manufactured by Dainichiseika Chemicals), 44.7 parts by mass of MEK, and 0.34 parts by mass of the infrared-shielding particle dispersion liquid according to Comparative Example 2 were mixed in a planetary mixer to prepare Coating Solution G according to Comparative Example 2. The resin cured film G obtained from a 200 μm-thick coating of Coating Solution G had a density of 0.13 g / m per unit area. 2 The formulation contains infrared shielding particles.

[0254] Coating Solution G was evaluated in the same manner as in Example 1. Comparative Example 3 The evaluation was carried out in the same manner as in Example 1, except that 0.8 parts by mass of the organic-inorganic hybrid infrared-shielding particles were added. When the infrared transmission prevention property was evaluated, infrared transmission was confirmed. Therefore, the infrared transmission prevention property after alkali immersion was not evaluated.

[0255] [Table 1] [Explanation of symbols]

[0256] 10. Infrared shielding fibers 11. Fiber 11A surface 11B Inside 12 Organic-inorganic hybrid infrared shielding particles 20 Infrared shielding textile structure 21 Fabric 21A surface 211 1st surface 212 2nd surface 21B Inside 22 Resin cured film

Claims

1. An infrared shielding fiber structure, A fabric including organic-inorganic hybrid infrared shielding particles and fibers, The organic-inorganic hybrid infrared shielding particles include infrared shielding particles and a coating resin that covers at least a part of the surface of the infrared shielding particles, The content of the infrared-shielding particles per unit area of ​​the infrared-shielding fiber structure is 0.10 g / m ２ 4.5g / m or more ２ The following is an infrared shielding fiber structure.

2. The infrared-shielding fiber structure according to claim 1 , wherein the organic-inorganic hybrid infrared-shielding particles are disposed at one or more positions selected from the surface and the interior of the fiber.

3. Further, a cured resin film is disposed at one or more positions selected from the surface and the interior of the fabric, The infrared shielding fiber structure according to claim 1 , wherein the cured resin film contains the organic-inorganic hybrid infrared shielding particles.

4. 2. The infrared-shielding fiber structure according to claim 1, wherein the coating resin contains one or more resins selected from polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, polyamide resin, vinyl chloride resin, olefin resin, fluororesin, polyvinyl acetate resin, polyurethane resin, acrylonitrile butadiene styrene resin, polyvinyl acetal resin, acrylonitrile-styrene copolymer resin, ethylene-vinyl acetate copolymer resin, phenol resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, polyimide resin, and silicone resin.

5. 2. The infrared-shielding fiber structure according to claim 1, wherein the coating resin is a photocurable resin, and the photocurable resin contains a resin that is cured by irradiation with any one of ultraviolet light, visible light, and infrared light.

6. The infrared shielding particles are represented by the general formula M ｘ W ｙ O ｚ 6. The infrared-shielding fiber structure according to any one of claims 1 to 5, comprising a composite tungsten oxide represented by the formula: (wherein the element M is one or more elements selected from H, He, 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, Be, Hf, Os, Bi, and I; and 0.001≦x / y≦1, 2.0≦z / y<4.0).

7. The infrared shielding fiber structure according to claim 1 , wherein the fibers include at least one type selected from the group consisting of synthetic fibers, semi-synthetic fibers, natural fibers, regenerated fibers, and inorganic fibers.

8. 8. The infrared-shielding fiber structure according to claim 7, wherein the synthetic fibers include one or more fibers selected from the group consisting of polyurethane fibers, polyamide fibers, acrylic fibers, polyester fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, and polyether ester fibers.

9. The infrared shielding fiber structure according to claim 7, wherein the semi-synthetic fiber comprises at least one type selected from the group consisting of cellulose-based fiber, protein-based fiber, chlorinated rubber, and hydrochloric rubber.

10. The infrared shielding fiber structure according to claim 7, wherein the natural fibers include at least one type selected from the group consisting of plant fibers, animal fibers, and mineral fibers.

11. The infrared shielding fiber structure according to claim 7, wherein the recycled fibers include at least one type selected from the group consisting of cellulose-based fibers, protein-based fibers, alginate fibers, rubber fibers, chitin fibers, and mannan fibers.

12. The infrared shielding fiber structure according to claim 7, wherein the inorganic fibers include at least one type selected from the group consisting of metal fibers, carbon fibers, and silicate fibers.

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