Infrared absorbing fibers and textile products

Abstract

Provided is an infrared absorbing fiber comprising a fiber and organic / inorganic hybrid infrared absorbing particles. The organic / inorganic hybrid infrared absorbing particles include: infrared absorbing particles; and a coating resin coating at least a part of the surface of the infrared absorbing particles. The content ratio of the infrared absorbing particles is 15-55% by mass. The organic / inorganic hybrid infrared absorbing particles are provided to at least one section selected from the inside and the surface of the fibers.

Description

[Technical Field]

[0001] The present invention relates to infrared absorbing fibers and textile products. [Background technology]

[0002] Various cold weather clothing, interior goods, and leisure goods with enhanced thermal insulation have been devised and put to practical use. The methods for increasing thermal insulation that have been put to practical use so far can be broadly divided into two types.

[0003] The first method is to maintain warmth by reducing the dissipation of heat generated by the human body. Specifically, for example, methods have been adopted to physically increase the air space in the cold weather clothing by controlling the weaving and knitting structure of the cold weather clothing or by making the fibers used hollow or porous.

[0004] The second method is to improve heat retention by actively storing heat, such as by radiating the heat generated by the human body back towards the human body or by converting part of the sunlight received by the cold weather clothing into heat.Specifically, for example, in the case of cold weather clothing, methods have been used in which chemical or physical processing is applied to the entire clothing or to the fibers that make up the clothing.

[0005] As described above, the first method has been to increase the number of air layers in the clothing, thicken the fabric, make the weave finer, or darken the color. Specific examples include winter clothing such as sweaters, and clothing often used for winter sports, in which padding is placed between the outer and inner layers and the thickness of the air layer in the padding maintains warmth. However, increasing the number of air layers by adding padding makes the clothing heavy and bulky, which is inconvenient for sports that require ease of movement. To solve this problem, the second method described above, which actively and effectively utilizes heat generated internally or from the outside, has recently begun to be adopted.

[0006] One method for implementing the second method is to deposit a metal such as aluminum or titanium onto the lining of clothing, and reflect the radiant heat emitted from the body onto the metal-deposited surface, thereby actively preventing heat dissipation. However, this method not only requires considerable cost to deposit the metal onto the clothing, but also leads to poor yields due to uneven deposition, which ultimately leads to an increase in the price of the product itself.

[0007] Another method proposed for implementing the second method involves kneading ceramic particles such as alumina, zirconia, and magnesia into the fibers themselves, and utilizing the far-infrared radiation effect and the ability to convert light into heat of these ceramic particles, i.e., actively incorporating external energy.

[0008] For example, Patent Document 1 states that the thermal conductivity is 0.3 kcal / m 2 The document discloses a heat-emitting fiber characterized by containing one or more inorganic fine particles having heat-emitting properties, containing at least one metal or metal ion, with a heat-emitting property of at least 100 sq. ft. sec. ° C. The inorganic fine particles having heat-emitting properties include silica or barium sulfate.

[0009] Patent Document 2 discloses a heat-retaining composite fiber comprising a thermoplastic polymer A having a melting point of 110°C or higher and a thermoplastic polymer B having a melting point of 15 to 50°C, a cooling crystallization temperature of 40°C or lower, and a heat of crystallization of 10 mJ / mg or higher, wherein the composite fiber contains ceramic microparticles having far-infrared radiation capability in an amount of 0.1 to 20% by weight relative to the fiber weight, and the surface of the fiber is covered with polymer A.

[0010] Patent Document 3 discloses an infrared absorbing processed textile product obtained by dispersing and fixing a binder resin containing an infrared absorbing agent made of at least one or more predetermined amino compounds in a textile product.

[0011] Patent Document 4 discloses a near-infrared absorbing processing method for a cellulosic fiber structure in which the spectral reflectance of the fabric is 65% or less in the near-infrared absorption range of 750 to 1500 nm by dyeing the structure with a dye that has greater absorption in the near-infrared region than black dye in combination with another dye.

[0012] The applicant of the present invention has proposed in Patent Documents 5, 6 and 7 fibers containing boride microparticles, tungsten oxide microparticles and composite tungsten oxide microparticles, and textile products obtained by processing such fibers.

[0013] Furthermore, according to the investigations of the present inventors, infrared absorbing particles such as tungsten oxide microparticles do not have sufficient chemical resistance, and when infrared absorbing fibers or textile products are exposed to a high-temperature chemical environment such as an acid or alkali, the infrared absorbing properties may deteriorate.

[0014] Therefore, the inventors of the present invention have proposed in Patent Document 8 an infrared absorbing fiber with chemical resistance. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Japanese Patent Publication No. 11-279830 [Patent Document 2] Japanese Patent Application Publication No. 5-239716 [Patent Document 3] Japanese Patent Publication No. 8-3870 [Patent Document 4] Japanese Patent Application Publication No. 9-291463 [Patent Document 5] Japanese Patent Publication No. 2005-9024 [Patent Document 6] Japanese Patent Application Publication No. 2006-132042 [Patent Document 7] International Publication No. 2019 / 054476 [Patent Document 8] Japanese Patent Publication No. 2021-75825 Summary of the Invention [Problem to be solved by the invention]

[0016] However, there is a demand for infrared absorbing fibers that have chemical resistance and yet have even higher infrared absorbing properties.

[0017] Therefore, one aspect of the present invention aims to provide an infrared absorbing fiber that combines chemical resistance and excellent infrared absorbing properties. [Means for solving the problem]

[0018] In one aspect of the invention, a fiber; and organic-inorganic hybrid infrared absorbing particles, the organic-inorganic hybrid infrared absorbing particles have infrared absorbing particles and a coating resin that covers at least a part of the surface of the infrared absorbing particles, and the content of the infrared absorbing particles is 15% by mass or more and 55% by mass or less, In the particle size distribution based on scattering intensity measured by a dynamic light scattering method, there is one peak and the median diameter is 800 nm or less, The infrared absorbing particles are represented by the general formula W y O z (W: tungsten, O: oxygen, 2.2≦z / y≦2.999), and tungsten oxide represented by the general formula M x W y O z (Element M is one or more elements selected from H, He, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, 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, Hf, Os, Bi, and I; and 0.001≦x / y≦1, 2.0≦z / y<4.0) containing one or more elements selected from composite tungsten oxides, The organic-inorganic hybrid infrared absorbing particles are disposed in one or more portions selected from the interior and the surface of the fiber to provide an infrared absorbing fiber. [Effects of the Invention]

[0019] According to one aspect of the present invention, it is possible to provide an infrared absorbing fiber that combines chemical resistance and excellent infrared absorbing properties. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram of the crystal structure of a composite tungsten oxide having a hexagonal crystal structure. [Figure 2] FIG. 2 is a cross-sectional schematic diagram of an organic-inorganic hybrid infrared absorbing particle. [Figure 3] FIG. 3 is a cross-sectional schematic diagram of an infrared absorbing fiber. [Figure 4] FIG. 4 is a transmission electron microscope photograph of the organic-inorganic hybrid infrared absorbing particles obtained in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention. [Infrared absorbing fiber] In this embodiment, an example of the configuration of the infrared absorbing fiber will be described.

[0022] The infrared absorbing fiber of this embodiment can include fibers and organic-inorganic hybrid infrared absorbing particles.

[0023] The organic-inorganic hybrid infrared-absorbing particles may have infrared-absorbing particles and a coating resin that covers at least a part of the surface of the infrared-absorbing particles. The organic-inorganic hybrid infrared-absorbing particles may have a content of the infrared-absorbing particles of 15% by mass or more and 55% by mass or less.

[0024] The organic-inorganic hybrid infrared absorbing particles can be disposed in one or more portions selected from the interior and surface of the fiber.

[0025] As mentioned above, infrared absorbing particles such as tungsten oxide fine particles used in infrared absorbing fibers and the like sometimes do not have sufficient chemical resistance.

[0026] Therefore, the inventors of the present invention have conducted extensive research into a method for producing infrared absorbing particles that combine chemical resistance and excellent infrared absorbing properties.

[0027] As a result, the researchers focused on organic-inorganic hybrid infrared-absorbing particles by disposing an organic material such as a resin directly on at least a portion of the surface of the infrared-absorbing particles. Furthermore, they discovered that by forming organic-inorganic hybrid infrared-absorbing particles with an infrared-absorbing particle content of 15% by mass or more and 55% by mass or less, which was particularly difficult to achieve in the past, and by forming an infrared-absorbing fiber containing the organic-inorganic hybrid infrared-absorbing particles, it is possible to achieve both chemical resistance and excellent infrared absorption properties.

[0028] Infrared absorbing particles are usually 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. For this reason, organic-inorganic hybrid infrared absorbing particles and methods for producing the same have not been known. In particular, methods for producing organic-inorganic hybrid infrared absorbing particles having a high content of infrared absorbing particles as described above have not been known. Therefore, the inventors of the present invention conducted research and discovered organic-inorganic hybrid infrared absorbing particles having a high content of infrared absorbing particles, in which an organic material is disposed on at least a portion of the surface of the infrared absorbing particles, and a method for producing the same.

[0029] The inventors have also found that by using such organic-inorganic hybrid infrared absorbing particles, it is possible to produce infrared absorbing fibers having chemical resistance and excellent infrared absorbing properties, and have completed the present invention.

[0030] First, a method for producing the organic-inorganic hybrid infrared absorbing particles and the organic-inorganic hybrid infrared absorbing particles will be described. 1. Manufacturing method for organic-inorganic hybrid infrared absorbing particles The infrared absorbing fiber of this embodiment can contain organic-inorganic hybrid infrared absorbing particles as described above. The method for producing such organic-inorganic hybrid infrared absorbing particles can include, for example, the following steps.

[0031] A dispersion liquid preparation step of preparing a dispersion liquid containing infrared absorbing particles, a dispersant, and a dispersion medium.

[0032] A dispersion medium reduction process in which the dispersion medium is evaporated from the dispersion liquid.

[0033] a raw material mixture preparation step of mixing the infrared absorbing particles recovered after the dispersion medium reduction step, a coating resin raw material, an organic solvent, an emulsifier, water, and a polymerization initiator to prepare a raw material mixture;

[0034] A stirring step in which the raw material mixture is stirred while being cooled.

[0035] A polymerization process in which a deoxidation treatment is carried out to reduce the amount of oxygen in the raw material mixture, followed by a polymerization reaction of the coating resin raw material.

[0036] Each step will be described below. (1) Dispersion liquid preparation process In the dispersion liquid preparation step, a dispersion liquid containing infrared absorbing particles, a dispersant, and a dispersion medium can be prepared.

[0037] Each material that can be suitably used when preparing the dispersion in the dispersion preparation step will be described below. (a) Infrared absorbing particles (Regarding composition, etc.) In the dispersion liquid preparation step, various infrared absorbing particles that are required to have improved chemical resistance, such as acid resistance or alkali resistance, can be used as the infrared absorbing particles. For example, it is preferable to use infrared absorbing particles containing various materials that contain free electrons, and it is more preferable to use infrared absorbing particles containing various inorganic materials that contain free electrons.

[0038] As the infrared absorbing particles, infrared absorbing particles containing one or more selected from tungsten oxide having oxygen deficiency and composite tungsten oxide can be particularly preferably used.When tungsten oxide having oxygen deficiency or composite tungsten oxide is used as the infrared absorbing particles, the organic-inorganic hybrid infrared absorbing particles containing the infrared absorbing particles can be light-colored and made inconspicuous.In this case, specifically, the infrared absorbing particles can be, for example, a compound represented by the general formula W y O z (W: tungsten, O: oxygen, 2.2≦z / y≦2.999), and tungsten oxide represented by the general formula M x W y O z (Element M is one or more elements selected from H, He, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, 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, Hf, Os, Bi, and I; and preferably contains one or more elements selected from composite tungsten oxides represented by the formula: 0.001≦x / y≦1, 2.0≦z / y<4.0).

[0039] It is generally known that materials containing free electrons exhibit a reflective / absorbent 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, as described above, can be suitably used as infrared-absorbing particles. For example, infrared-absorbing particles made smaller than the wavelength of light are preferred because they can reduce geometric scattering in the visible light range (wavelengths of 380 nm to 780 nm) and achieve particularly high transparency in the visible light range.

[0040] In this specification, the term "transparency" is used to mean "high transmittance with little scattering of light in the visible light range."

[0041] Generally, tungsten oxide (WO3) does not have any effective free electrons, so it has little absorption / reflection characteristics in the infrared region and is not effective as an infrared absorbing particle.

[0042] On the other hand, WO3 with oxygen deficiency and composite tungsten oxides in which electropositive elements such as Na are added to WO3 are known to be conductive materials with free electrons. Furthermore, analysis of single crystals of these materials with free electrons has suggested that the free electrons respond to light in the infrared region.

[0043] 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 absorbing material, and it is possible to obtain a tungsten oxide or composite tungsten oxide that is transparent in the visible light region and has particularly strong absorption in the infrared region.

[0044] Therefore, tungsten oxide and composite tungsten oxide, which are one type of material for infrared absorbing particles that can be suitably used in the dispersion preparation step, will be further described below. (a1) Tungsten oxide Tungsten oxide has the general formula W y O z (W is tungsten, O is oxygen, 2.2≦z / y≦2.999).

[0045] General formula W y O z In the tungsten oxide represented by the formula (1), the composition range of tungsten and oxygen is preferably such that the composition ratio of oxygen to tungsten (z / y) is less than 3, more preferably 2.2≦z / y≦2.999, and even more preferably 2.45≦z / y≦2.999.

[0046] If the value of z / y is 2.2 or more, it is possible to prevent the appearance of an undesired WO2 crystalline phase in the tungsten oxide, and the chemical stability of the material can be obtained, making the infrared absorbing particles particularly effective.

[0047] Furthermore, by making the z / y value preferably less than 3, more preferably 2.999 or less, a particularly sufficient amount of free electrons is generated to enhance the absorption and reflection characteristics in the infrared region, resulting in efficient infrared absorbing particles.

[0048] Furthermore, the so-called "Magnéli phase" having a composition ratio expressed as 2.45≦z / y≦2.999 is chemically stable and has excellent light absorption properties in the near-infrared region, so it can be more preferably used as an infrared absorbing material. Therefore, it is more preferable that the above z / y is 2.45≦z / y≦2.999, as described above. (a2) Composite tungsten oxide The composite tungsten oxide is obtained by adding element M to the above-mentioned WO3.

[0049] By adding element M to form a composite tungsten oxide, free electrons are generated in the WO3, and strong absorption characteristics resulting from the free electrons are manifested, particularly in the near-infrared region, making the particles effective at absorbing near-infrared light with a wavelength of around 1000 nm.

[0050] That is, by controlling the amount of oxygen in WO3 and adding element M, which generates free electrons, to form a composite tungsten oxide, it is possible to exhibit more efficient infrared absorption characteristics. The general formula of the composite tungsten oxide obtained by controlling the amount of oxygen in WO3 and adding element M, which generates free electrons, 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.

[0051] 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 absorption effect can be obtained. The greater the amount of element M added, the greater the supply of free electrons and the higher the infrared absorption 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, it is preferable because this can prevent the generation of impurity phases in the infrared absorbing particles containing the composite tungsten oxide.

[0052] The element M is preferably one or more elements selected from H, He, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, 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, Hf, Os, Bi, and I.

[0053] M x W y O z From the viewpoint of particularly enhancing the stability in the above range, the element M is more preferably one or more elements selected from Li, Na, K, Rb, Cs, Fr, Mg, Ca, Sr, Ba, Ra, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, 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. From the viewpoint of improving the optical properties and weather resistance of the infrared absorbing particles containing the composite tungsten oxide, it is more preferable that the element M is one or more elements selected from alkali metals, alkaline earth metal elements, transition metal elements, Group 4B elements, and Group 5B elements.

[0054] The z / y value, which indicates the amount of oxygen added, isx W y O z In the composite tungsten oxide represented by y O z In addition to the fact that the same mechanism as that of tungsten oxide, expressed as: works, 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. Therefore, 2.0≦z / y<4.0 is preferable, 2.2≦z / y<4.0 is more preferable, and 2.45≦z / y<4.0 is even more preferable.

[0055] In particular, when the composite tungsten oxide has a hexagonal crystal structure, the infrared absorbing particles containing the composite tungsten oxide have improved light transmittance in the visible light region and improved light absorption in the infrared region. This will be explained with reference to Fig. 1, which is a schematic plan view of a hexagonal crystal structure.

[0056] FIG. 1 shows a projection of the crystal structure of a composite tungsten oxide having a hexagonal crystal structure as viewed from the (001) direction, with a unit cell 10 indicated by a dotted line.

[0057] In Figure 1, six octahedra 11 formed by WO6 units are assembled to form a hexagonal void 12, and an element 121, which is element M, is placed in the void 12 to form one unit, and many of these units are assembled to form a hexagonal crystal structure.

[0058] In order to improve the transmission of light in the visible light region and the absorption of light in the infrared region, the composite tungsten oxide needs to contain the unit structure explained with reference to Fig. 1. Therefore, the composite tungsten oxide may be crystalline or amorphous.

[0059] When cations of element M are added and present in the above-mentioned hexagonal voids, light transmission in the visible light region is improved and light absorption in the infrared region is improved. Generally, the hexagonal crystal is easily formed when an element M with a large ionic radius is added. Specifically, the hexagonal crystal is easily formed when one or more elements selected from Cs, K, Rb, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn are added as the element M. Of course, elements other than these may also be used as long as the above-mentioned element M is present in the hexagonal voids formed by the WO6 units, and the present invention is not limited to the above-mentioned elements.

[0060] 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.

[0061] In addition, infrared-absorbing particles containing composite tungsten oxides other than hexagonal crystals, such as tetragonal and cubic crystals, also have sufficiently effective infrared absorption properties. The absorption position in the infrared region tends to change depending on the crystal structure, with the absorption position tending to shift toward longer wavelengths in the order of cubic crystals < tetragonal crystals < hexagonal crystals. Concomitantly, the order of least absorption of light in the visible region is hexagonal, tetragonal, and cubic crystals. Therefore, for applications requiring greater transmission of light in the visible region and greater shielding of light in the infrared region, it is preferable to use a hexagonal composite tungsten oxide. However, the 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.

[0062] Infrared absorbing particles containing tungsten oxide or composite tungsten oxide have a high absorption rate in the near-infrared region, particularly in the vicinity of 1000 nm wavelength, and therefore often have a transmitted color tone ranging from blue to green. (Dispersed particle size) The dispersed particle size of the infrared absorbing particles is not particularly limited and can be selected depending on the intended use and the like.

[0063] First, when used in applications where transparency must be maintained, it is preferable that the infrared-absorbing particles have a dispersed particle diameter of 800 nm or less. This is because particles with a dispersed particle diameter of 800 nm or less do not completely block light due to scattering, and can maintain visibility in the visible light range while efficiently maintaining transparency. In particular, when transparency in the visible light range is important, it is preferable to further consider reducing scattering by the particles.

[0064] When reducing scattering by particles is important, the dispersed particle diameter is preferably 200 nm or less, and more preferably 100 nm or less. This is because a small dispersed particle diameter reduces scattering of light in the visible light region with wavelengths of 380 nm to 780 nm due to geometric scattering or Mie scattering, which can prevent, for example, an infrared absorbing film containing dispersed infrared absorbing particles from becoming like frosted glass and losing clear transparency. In other words, when the dispersed particle diameter is 200 nm or less, the geometric scattering or Mie scattering is reduced, resulting in the Rayleigh scattering region. In the Rayleigh scattering region, scattered light decreases in proportion to the sixth power of the particle diameter, so scattering decreases and transparency improves as the dispersed particle diameter decreases.

[0065] Furthermore, if the dispersed particle size is 100 nm or less, scattered light will be extremely reduced, which is preferable. From the viewpoint of avoiding light scattering, a small dispersed particle size is preferable.

[0066] There is no particular lower limit to the dispersed particle size of the infrared absorbing particles, but the dispersed particle size is preferably 1 nm or more, for example, in order to facilitate industrial production.

[0067] By setting the dispersed particle diameter of the infrared absorbing particles to 800 nm or less, the haze value of the infrared absorbing particle dispersion in which the infrared absorbing particles are dispersed in a medium can be set to 30% or less at a visible light transmittance of 85% or less. Setting the haze to 30% or less prevents the infrared absorbing particle dispersion from becoming like frosted glass, and particularly clear transparency can be obtained.

[0068] The dispersed particle size of the infrared absorbing particles can be measured using an instrument such as ELS-8000 manufactured by Otsuka Electronics Co., Ltd., which is based on the principle of dynamic light scattering. (crystallite diameter) Furthermore, from the viewpoint of exhibiting excellent infrared absorption properties, the crystallite diameter of the infrared absorbing particles is preferably 1 nm or more and 200 nm or less, more preferably 1 nm or more and 100 nm or less, and even more preferably 10 nm or more and 70 nm or less. The crystallite diameter can be measured by measuring an X-ray diffraction pattern by powder X-ray diffraction (θ-2θ method) and analyzing by the Rietveld method. The X-ray diffraction pattern can be measured using, for example, a powder X-ray diffractometer "X'Pert-PRO / MPD" manufactured by PANalytical, Spectris Co., Ltd. (b) Dispersant The dispersant is used for the purpose of hydrophobizing the surface of the infrared absorbing particles. The dispersant can be selected according to the dispersion system, which is a combination of the infrared absorbing 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 absorbing particles are tungsten oxide or composite tungsten oxide, it is more preferable that the dispersant have an amino group as the functional group.

[0069] 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.

[0070] Furthermore, since the dispersant is used for the purpose of hydrophobizing the surface of the infrared-absorbing 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, which can also be used as a coating resin raw material, can be used. 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.

[0071] The amount of dispersant added is not particularly limited and can be selected arbitrarily. A suitable amount of dispersant added can be selected depending on the type of dispersant and infrared-absorbing particles, the specific surface area of ​​the infrared-absorbing 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-absorbing particles, since this makes it easier to prepare a dispersion in a particularly good dispersion 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-absorbing particles. (c) Dispersion medium The dispersion medium may be any medium that can disperse the infrared absorbing particles and the dispersant described above to form a dispersion liquid, and for example, various organic compounds can be used.

[0072] As the dispersion medium, for example, one or more selected from aromatic hydrocarbons such as toluene and xylene can be suitably used.

[0073] In the dispersion preparation step, the dispersion can be prepared by mixing the infrared absorbing particles, the dispersant, and the dispersion medium. In order to reduce the dispersed particle size of the infrared absorbing particles and to disperse them uniformly in the dispersion, it is preferable to perform a pulverization treatment of the infrared absorbing particles at the same time as mixing.

[0074] The mixing means used when mixing and pulverizing the infrared absorbing 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 absorbing 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. (2) Dispersion medium reduction process In the dispersion medium reducing step, the dispersion medium can be evaporated and dried from the dispersion liquid.

[0075] In the dispersion medium reducing step, it is preferable that the dispersion medium is sufficiently evaporated from the dispersion liquid so that the infrared absorbing particles can be recovered.

[0076] 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.

[0077] 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 absorbing particles are obtained after the dispersion medium reduction step.

[0078] By evaporating the dispersion medium, the dispersant is disposed around the infrared absorbing particles, and infrared absorbing particles having hydrophobic surfaces can be obtained. This makes it possible to enhance adhesion between the hydrophobically treated infrared absorbing 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 absorbing particles by a polymerization step or the like described below. (3) Raw material mixture preparation process In the raw material mixture preparation step, the infrared absorbing 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.

[0079] The infrared absorbing particles recovered after the dispersion medium reduction step may have the dispersant supplied in the dispersion liquid preparation step attached to their surfaces, making them dispersant-containing infrared absorbing particles. Therefore, when the dispersant is attached to the infrared absorbing particles in this way, the dispersant-containing infrared absorbing particles recovered after the dispersion medium reduction step will be used as the infrared absorbing particles in the raw material mixture liquid preparation step.

[0080] Hereinafter, each material other than the infrared absorbing 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 absorbing 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] The photocurable resin may be, for example, a resin that is cured by irradiation with ultraviolet light, visible light, or infrared light.

[0085] 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 resin or a thermosetting polyurethane resin.

[0086] 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.

[0087] 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 a polystyrene resin, styrene can be used as the coating resin raw material.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] Examples of cationic emulsifiers include alkylamine salts and quaternary ammonium salts.

[0092] Examples of anionic emulsifiers include acid salts and ester salts.

[0093] Examples of nonionic emulsifiers include various esters, various ethers, various ester ethers, alkanolamides, and the like.

[0094] As the emulsifier, for example, one or more types selected from the above-mentioned materials can be used.

[0095] Among these, it is preferable to use a cationic emulsifier, that is, a surfactant exhibiting cationic properties, from the viewpoint of making it particularly easy to form the organic-inorganic hybrid infrared absorbing particles.

[0096] 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.

[0097] Furthermore, when an amine compound is used as a dispersant, it may be difficult to form organic-inorganic hybrid infrared-absorbing 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 it 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).

[0098] Furthermore, 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 according to the amount of emulsifier added, it is possible to make the content of infrared absorbing particles in the resulting organic-inorganic hybrid infrared absorbing particles 15% by mass or more. 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 content of infrared absorbing particles is 15% by mass or more. However, these conditions vary depending on the type of emulsifier, etc., so they are not particularly limited, and 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.

[0099] 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.

[0100] Examples of the ionic polymerization initiator include nucleophiles such as n-butyllithium, and electrophiles such as protonic acids, Lewis acids, halogen molecules, and carbocations.

[0101] 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.

[0102] 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.

[0103] In the raw material mixture preparation step, the infrared absorbing 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. 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 absorbing particles recovered after the dispersion medium reduction step are dispersed in an organic solvent.

[0104] 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.

[0105] Then, the organic phase is added to the aqueous phase and mixed to prepare a raw material mixture.

[0106] In order to distribute the coating resin more uniformly on the surfaces of the infrared absorbing 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 absorbing particles recovered after the dispersion medium reduction step, the coating resin raw material, the organic solvent, the emulsifier, water, and the polymerization initiator.

[0107] 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 perform stirring so that, for example, oil-in-water droplets in which the infrared absorbing particles encapsulated in the coating resin raw material are dispersed in the aqueous phase are formed. Note that the stirring step may be omitted and may be performed together with the stirring process described below.

[0108] 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, and the ratio of the amount of coating resin raw material to the amount of infrared-absorbing particles added. 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-absorbing particles are sufficiently coated with the coating resin. The amount of polymerization initiator added is more preferably 0.1 mol% to 200 mol% of the coating resin raw material, and even more preferably 0.2 mol% to 100 mol%. (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.

[0109] 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 of a predetermined size.

[0110] 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.

[0111] 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 absorbing particles.

[0112] In the stirring step, specifically, for example, 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, it is preferable that the particle size distribution of the miniemulsion obtained 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-absorbing particles produced using the miniemulsion have excellent dispersibility in various media such as dispersion media, making it easy to form infrared-absorbing dispersions, infrared-absorbing dispersions, and infrared-absorbing fibers. Furthermore, the infrared absorption properties of the obtained infrared-absorbing dispersions, infrared-absorbing dispersions, and infrared-absorbing fibers can be particularly improved.

[0113] The mini-emulsion obtained in the stirring step preferably has a median diameter D50 of 1 μm or less and a standard deviation of 500 or less in particle size distribution based on scattering intensity measured by dynamic light scattering.

[0114] By setting D50 to 1 μm or less, the dispersibility of the organic-inorganic hybrid infrared-absorbing particles produced using the miniemulsion can be particularly improved when they are made into an infrared-absorbing dispersion, an infrared-absorbing dispersion, infrared-absorbing fibers, etc. Furthermore, by setting the standard deviation to 500 or less, the broadening of the particle size distribution of the organic-inorganic hybrid infrared-absorbing particles produced using the miniemulsion can be particularly suppressed. Therefore, when the organic-inorganic hybrid infrared-absorbing particles are used to make an infrared-absorbing dispersion, an infrared-absorbing dispersion, infrared-absorbing fibers, etc., they are easily dispersed uniformly in the infrared-absorbing dispersion, infrared-absorbing dispersion, or infrared-absorbing fibers, and the infrared absorption properties can be particularly improved.

[0115] The D50 is more preferably 800 nm or less, and even more preferably 500 nm or less. The lower limit of D50 is not particularly limited, but from the viewpoint of containing a sufficient amount of infrared absorbing particles, it is preferably 100 nm or more, and more preferably 150 nm or more.

[0116] The standard deviation is more preferably 400 or less, even more preferably 300 or less, and particularly preferably 250 or less. There are no particular restrictions on the lower limit of the standard deviation, but it is, for example, preferably 20 or more, more preferably 50 or more, and even more preferably 100 or more. By making the standard deviation 20 or more, the productivity of the mini-emulsion can be increased.

[0117] In the stirring step, the specific conditions for obtaining a mini-emulsion having the above particle size characteristics 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.

[0118] 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.

[0119] 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. (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.

[0120] 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 absorbing particle. In this case, it is preferable that the polymerization step results in organic-inorganic hybrid infrared absorbing particles in which the infrared absorbing particles are disposed in resin capsules.

[0121] 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.

[0122] The specific conditions for carrying out the polymerization reaction are not particularly limited, as they can be selected arbitrarily depending on the coating resin raw material added to the raw material mixture, etc., but the polymerization reaction can be advanced, for example, by heating the raw material mixture or irradiating it with light of a predetermined wavelength.

[0123] According to the method for producing organic-inorganic hybrid infrared-absorbing particles of the present embodiment described above, it is possible to obtain organic-inorganic hybrid infrared-absorbing particles by disposing an organic material such as a resin on at least a portion of the surface of the infrared-absorbing 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, it is possible to prevent the infrared-absorbing particles from coming into direct contact with the chemical component such as an acid or alkali, thereby achieving excellent chemical resistance and preventing a decrease in the infrared absorption properties.

[0124] Furthermore, the method for producing organic-inorganic hybrid infrared-absorbing particles of this embodiment makes it possible to produce organic-inorganic hybrid infrared-absorbing particles having a high content of infrared-absorbing particles of 15 mass% or more, which has been particularly difficult to produce in the past, and therefore makes it possible to obtain organic-inorganic hybrid infrared-absorbing particles that are excellent not only in chemical resistance but also in infrared-shielding properties. 2. Organic-inorganic hybrid infrared absorbing particles The organic-inorganic hybrid infrared absorbing particles of this embodiment preferably have infrared absorbing particles and a coating resin that covers at least a part of the surface of the infrared absorbing particles. It is more preferable that the coating resin forms a resin capsule and the infrared absorbing particles are disposed in the resin capsule. That is, it is more preferable that the entire surface of the infrared absorbing particles is covered with the coating resin.

[0125] The organic-inorganic hybrid infrared absorbing particles may have a content of infrared absorbing particles of 15% by mass or more and 55% by mass or less.

[0126] As mentioned above, infrared-absorbing 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-absorbing particles, organic-inorganic hybrid infrared-absorbing particles with a high infrared-absorbing particle content can be produced. By disposing a coating resin on at least a portion of the surface of the infrared-absorbing particles, even when the organic-inorganic hybrid infrared-absorbing particles are exposed to a high-temperature acid, alkali, or other chemical environment, the infrared-absorbing particles are prevented from coming into direct contact with chemical components such as acid or alkali, thereby imparting chemical resistance. As described above, by disposing the infrared-absorbing particles in a resin capsule, chemical resistance can be particularly enhanced.

[0127]

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

[0128] Fig. 2 shows a cross-sectional schematic diagram of an organic-inorganic hybrid infrared absorbing particle 20 of this embodiment. As shown in Fig. 2, in the organic-inorganic hybrid infrared absorbing particle 20 of this embodiment, a coating resin 22 is disposed on at least a part of the surface of an infrared absorbing particle 21.

[0129] In particular, as shown in Fig. 2, the organic-inorganic hybrid infrared absorbing particles 20 of this embodiment preferably have a configuration in which the infrared absorbing particles 21 are disposed in a resin capsule 221 formed by a coating resin 22. As shown in Fig. 2, a plurality of infrared absorbing particles 21 may be disposed in one resin capsule 221, or only one infrared absorbing particle 21 may be disposed in one resin capsule 221. Furthermore, the infrared absorbing particles 21 may be unevenly distributed in the resin capsule 221, but are preferably dispersed.

[0130] It is sufficient that at least a portion of the infrared absorbing particles 21 is covered by the resin capsules 221, and a portion of the infrared absorbing particles 21 may be exposed to the outer surface of the resin capsules 221. However, it is preferable that the infrared absorbing particles 21 are completely covered by the resin capsules 221, that is, encapsulated in the resin capsules 221. This is because, by completely covering the infrared absorbing particles 21 with the resin capsules 221, even when the organic-inorganic hybrid infrared absorbing particles come into contact with various chemical components, the infrared absorbing particles 21 can be more reliably prevented from coming into contact with the chemicals, thereby particularly improving chemical resistance.

[0131] 2 is merely a schematic illustration for the purpose of explanation, and the organic-inorganic hybrid infrared-absorbing particles of this embodiment are not limited to this form. For example, the shape, size, arrangement, and distribution of the infrared-absorbing particles 21 and the shape and arrangement of the coating resin 22 are not limited to this form. (1) Components of the organic-inorganic hybrid infrared absorbing particles The components of the organic-inorganic hybrid infrared absorbing particles of this embodiment will be described below. (1-1) 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 absorbing 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.

[0132] 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.

[0133] 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.

[0134] The photocurable resin may be, for example, a resin that is cured by irradiation with ultraviolet light, visible light, or infrared light.

[0135] 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.

[0136] 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.

[0137] 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. (1-2) Infrared absorbing particles The infrared absorbing particles have already been described in the method for producing organic-inorganic hybrid infrared absorbing particles, and therefore further description will be omitted. For example, it is preferable to use infrared absorbing particles containing various materials that contain free electrons, and it is more preferable to use infrared absorbing particles containing various inorganic materials that contain free electrons.

[0138] The infrared absorbing particles are particularly preferably infrared absorbing particles containing one or more selected from tungsten oxides having oxygen deficiency and composite tungsten oxides. In this case, specifically, the infrared absorbing particles are, for example, those represented by the general formula W y O z (W: tungsten, O: oxygen, 2.2≦z / y≦2.999), and tungsten oxide represented by the general formula M x W y O z (Element M is one or more elements selected from H, He, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, 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, Hf, Os, Bi, and I; and preferably contains one or more elements selected from composite tungsten oxides represented by the formula: 0.001≦x / y≦1, 2.0≦z / y<4.0).

[0139] The organic-inorganic hybrid infrared-absorbing 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, such as an acid or alkali, the infrared-absorbing particles are prevented from coming into direct contact with chemical components such as acid or alkali, thereby providing excellent chemical resistance and preventing a deterioration in infrared absorption properties. Furthermore, infrared-absorbing fibers using the organic-inorganic hybrid infrared-absorbing particles can also be provided with chemical resistance. (2) Content of infrared absorbing particles According to the investigations of the inventors of the present invention, the use of organic-inorganic hybrid infrared absorbing particles can improve chemical resistance, but in order to exhibit particularly high infrared shielding properties, it is necessary to increase the content of infrared absorbing particles.

[0140] Therefore, the content of the infrared absorbing particles in the organic-inorganic hybrid infrared absorbing particles of this embodiment is preferably 15% by mass or more, and more preferably 20% by mass or more.

[0141] However, if the content of the infrared absorbing particles is too high, the degree to which the infrared absorbing particles are covered with the coating resin may decrease. Therefore, the content of the infrared absorbing particles is preferably 55% by mass or less, and more preferably 50% by mass or less. (3) Particle size distribution of organic-inorganic hybrid infrared absorbing particles According to the inventors' investigations, the organic-inorganic hybrid infrared-absorbing particles of this embodiment preferably have one peak in the particle size distribution based on scattering intensity measured by dynamic light scattering. That is, the particle size distribution preferably does not have two or more peaks. When the particle size distribution of the organic-inorganic hybrid infrared-absorbing particles is represented by one peak, they have excellent dispersibility in various media such as dispersion media, making it easy to form infrared-absorbing dispersions, infrared-absorbing dispersions, and infrared-absorbing fibers. Furthermore, the infrared absorption properties of the resulting infrared-absorbing dispersions, infrared-absorbing dispersions, and infrared-absorbing fibers can be particularly improved.

[0142] The organic-inorganic hybrid infrared absorbing particles of this embodiment preferably have a median diameter D50 of 1 μm or less and a standard deviation of 500 or less in a particle size distribution based on scattering intensity measured by a dynamic light scattering method.

[0143] By making D50 1 μm or less, it is possible to particularly improve dispersibility when preparing an infrared absorbing dispersion containing the organic-inorganic hybrid infrared absorbing particles, an infrared absorbing dispersion, an infrared absorbing fiber, etc. Furthermore, by making the standard deviation 500 or less, it is possible to particularly suppress the broadening of the particle size distribution of the organic-inorganic hybrid infrared absorbing particles, and when preparing an infrared absorbing dispersion, an infrared absorbing dispersion, an infrared absorbing fiber, etc., the particles are easily dispersed uniformly in the infrared absorbing dispersion, the infrared absorbing dispersion, or the infrared absorbing fiber, and it is possible to particularly improve the infrared shielding properties.

[0144] 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 containing a sufficient amount of infrared absorbing particles, it is preferably 30 nm or more, more preferably 50 nm or more, and even more preferably 100 nm or more.

[0145] The standard deviation is more preferably 400 or less, even more preferably 300 or less, and particularly preferably 250 or less. There are no particular restrictions on the lower limit of the standard deviation, but it is, for example, preferably 20 or more, more preferably 50 or more, and even more preferably 100 or more. By making the standard deviation 20 or more, the productivity of the organic-inorganic hybrid infrared-absorbing particles can be increased.

[0146] The infrared absorbing fiber of this embodiment can contain fibers in addition to the organic-inorganic hybrid infrared absorbing particles described above.

[0147] The infrared absorbing fiber of this embodiment can be produced by dispersing the organic-inorganic hybrid infrared absorbing particles described above in an appropriate medium and incorporating the dispersion into one or more portions selected from the interior and surface of the fiber. The fiber etc. will be described below. 3. Fiber The infrared absorbing fiber of this embodiment may be selected from a variety of fibers depending on the application.

[0148] The fibers contained in the infrared-absorbing fiber of this embodiment may include, for example, one or more types selected from synthetic fibers, semi-synthetic fibers, natural fibers, regenerated fibers, and inorganic fibers. Specifically, the fibers may be, for example, one or more types selected from the 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-absorbing particles can be incorporated into the fibers and the durability of heat retention, the fibers preferably include synthetic fibers, and more preferably are synthetic fibers.

[0149] When the infrared-absorbing fiber of this embodiment contains synthetic fibers as fibers, the specific type of the synthetic fibers is not particularly limited. For example, the synthetic fibers may be one or more types selected from polyurethane fibers, polyamide fibers, acrylic fibers, polyester fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, polyether ester fibers, etc.

[0150] 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.

[0151] Examples of acrylic fibers include one or more types selected from polyacrylonitrile, acrylonitrile-vinyl chloride copolymer, modacrylic, and the like.

[0152] Examples of polyester fibers include one or more types selected from polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and the like.

[0153] The polyolefin fiber may be one or more types selected from, for example, polyethylene, polypropylene, polystyrene, and the like.

[0154] Examples of polyvinyl alcohol fibers include vinylon.

[0155] Examples of polyvinylidene chloride fibers include vinylidene.

[0156] Examples of polyvinyl chloride fibers include polyvinyl chloride.

[0157] The polyetherester fiber may be one or more types selected from, for example, Rexe, Success, and the like.

[0158] When the infrared absorbing fiber of this embodiment 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.

[0159] The cellulosic fibers include, for example, one or more types selected from acetate, triacetate, acetate oxide, and the like.

[0160] Examples of protein-based fibers include Promix.

[0161] When the infrared absorbing fiber of this embodiment 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.

[0162] 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.

[0163] 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.

[0164] The mineral fiber may be one or more types selected from, for example, asbestos.

[0165] When the infrared absorbing fiber of this embodiment 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.

[0166] The cellulosic fibers include, for example, one or more types selected from rayon, viscose rayon, cupro, polynosic, cuprammonium rayon, and the like.

[0167] 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.

[0168] When the infrared absorbing fiber 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.

[0169] The metal fibers include, for example, one or more types selected from fibers of various metals, gold thread, silver thread, heat-resistant alloy fiber, and the like.

[0170] Examples of silicate fibers include one or more types selected from glass fibers, slag fibers, rock fibers, and the like.

[0171] The cross-sectional shape of the infrared-absorbing fiber of this embodiment is not particularly limited, and examples thereof include one or more types selected from circular, triangular, hollow, flat, Y-shaped, star-shaped, core-sheath, etc. The infrared-absorbing fiber of this embodiment may also contain fibers of different cross-sectional shapes.

[0172] The organic-inorganic hybrid infrared-absorbing particles can be arranged in one or more selected portions from 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 fiber shape of the infrared-absorbing fiber of this embodiment may be either filament (long fiber) or staple (short fiber). 4. Additives The infrared absorbing fiber of this embodiment may contain antioxidants, flame retardants, deodorizers, insect repellents, antibacterial agents, ultraviolet absorbers, etc. depending on the purpose, within the range that does not impair the performance of the fiber.

[0173] Furthermore, the infrared-absorbing fiber of this embodiment may further contain particles capable of emitting far-infrared rays in addition to the infrared-absorbing material. The particles capable of emitting far-infrared rays may be disposed, for example, in one or more portions selected from the interior and surface of the fiber. Suitable particles capable of emitting far-infrared rays include, for example, one or more selected from metal oxides such as ZrO2, SiO2, TiO2, Al2O3, MnO2, MgO, Fe2O3, and CuO; carbides such as ZrC, SiC, and TiC; and nitrides such as ZrN, Si3N4, and AlN.

[0174] The organic-inorganic hybrid infrared-absorbing particles, which are an infrared-absorbing material and a near-infrared-absorbing material possessed by the infrared-absorbing fiber of this embodiment, have the property of absorbing solar light energy with a wavelength of 0.3 μm or more and 3 μm or less, and in particular selectively absorb the near-infrared region with a wavelength of around 0.9 μm or more and 2.2 μm or less, and convert it into heat or re-radiate it.

[0175] Meanwhile, the particles capable of emitting far-infrared rays described above have the ability to receive the energy absorbed by the organic-inorganic hybrid infrared-absorbing particles, which are near-infrared absorbing materials, and convert this energy into thermal energy with mid- to far-infrared wavelengths, which can then be radiated. For example, ZrO2 particles convert this energy into thermal energy with a wavelength of 2 μm or more and 20 μm or less, and then radiate it. Therefore, when the particles capable of emitting far-infrared rays and the organic-inorganic hybrid infrared-absorbing particles coexist within or on the surface of a fiber, for example, the solar energy absorbed by the organic-inorganic hybrid infrared-absorbing particles is efficiently consumed within and on the surface of the fiber, resulting in more effective heat retention.

[0176] Fig. 3 shows a cross-sectional schematic diagram of an infrared absorbing fiber 30 of this embodiment taken along a plane passing through the central axis thereof. As shown in Fig. 3, the infrared absorbing fiber 30 of this embodiment can have organic-inorganic hybrid infrared absorbing particles 32 disposed in one or more portions selected from the interior 31B and the surface 31A of the fiber 31. That is, in the infrared absorbing fiber 30 of this embodiment, the organic-inorganic hybrid infrared absorbing particles can be disposed in both the interior 31B and the surface 31A of the fiber 31, or in either the interior 31B or the surface 31A of the fiber 31.

[0177] 3 shows an example in which the organic-inorganic hybrid infrared-absorbing particles 32 are arranged on both the surface 31A and the interior 31B of the fiber 31, but as described above, the present invention is not limited to this configuration and the particles may be arranged on only one of the surfaces 31A and the interior 31B of the fiber 31. FIG. 3 merely shows a schematic diagram of the infrared-absorbing fiber 30, and the distribution, shape, size, etc. of the organic-inorganic hybrid infrared-absorbing particles 32 are not limited to this configuration.

[0178] As described above, the organic-inorganic hybrid infrared absorbing particles have both chemical resistance and excellent infrared absorbing properties, and therefore the infrared absorbing fiber of the present embodiment containing the organic-inorganic hybrid infrared absorbing particles can also have both chemical resistance and excellent infrared absorbing properties. [Infrared absorbing fiber manufacturing method]

[0179] The method for producing the infrared absorbing fiber of this embodiment is not particularly limited, and the fiber can be produced by disposing organic-inorganic hybrid infrared absorbing particles in one or more portions selected from the surface and the interior of the fiber.

[0180] For example, the infrared absorbing fiber of this embodiment can be produced by the following production methods (a) to (d).

[0181] (a) A method of spinning organic-inorganic hybrid infrared absorbing particles directly into the raw polymer of synthetic fibers.

[0182] (b) A method in which a masterbatch is prepared in advance by incorporating a high concentration of organic-inorganic hybrid infrared absorbing particles into a portion of the raw polymer, and this is diluted and adjusted to the desired concentration before spinning.

[0183] (c) A method in which the organic-inorganic hybrid infrared-absorbing particles are uniformly dispersed in a raw material monomer or oligomer solution in advance, and the target raw material polymer is synthesized using this dispersion, and at the same time, the organic-inorganic hybrid infrared-absorbing particles are dispersed in the raw material polymer, and then the polymer is spun.

[0184] (d) A method in which organic-inorganic hybrid infrared absorbing particles are attached to the surface of fibers obtained by spinning in advance using a binder or the like.

[0185] Here, the above-mentioned manufacturing methods (a) to (d) for incorporating organic-inorganic hybrid infrared-absorbing particles into the fibers of the infrared-absorbing fiber of this embodiment will be described with specific examples.

[0186] Method (a): For example, a case where polyester fibers are used as the fibers will be described.

[0187] A dispersion of organic-inorganic hybrid infrared-absorbing particles 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 organic-inorganic hybrid infrared-absorbing particles. This masterbatch containing organic-inorganic hybrid infrared-absorbing particles is melt-mixed at a temperature near the melting temperature of the resin and spun, for example, according to various known methods.

[0188] In this case, a dispersant can be added to improve the dispersibility of the organic-inorganic hybrid infrared-absorbing particles in the polyethylene terephthalate resin. The dispersant is not particularly limited as long as it can disperse the organic-inorganic hybrid infrared-absorbing 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.

[0189] 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-absorbing particles, thereby more reliably preventing the aggregation of the organic-inorganic hybrid infrared-absorbing particles. Therefore, they can be used advantageously because they can disperse the organic-inorganic hybrid infrared-absorbing particles more uniformly.

[0190] 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.

[0191] Method (b): A masterbatch containing organic-inorganic hybrid infrared-absorbing particles is prepared using a method similar to that in (a), and the masterbatch is melt-mixed with a masterbatch of polyethylene terephthalate to which no organic-inorganic hybrid infrared-absorbing particles have been added at a desired mixing ratio near the melting temperature of the resin, followed by spinning according to a known method.

[0192] Method (c): For example, a case where urethane fibers are used as the fibers will be described.

[0193] A polymeric diol containing organic-inorganic hybrid infrared-absorbing 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.

[0194] Method (d): For example, a case where organic-inorganic hybrid infrared absorbing particles are attached to the surface of natural fibers will be described.

[0195] First, a treatment liquid is prepared by mixing organic-inorganic hybrid infrared absorbing particles, one or more binder resins selected from acrylic, epoxy, urethane, and polyester, and a solvent such as water.

[0196] 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-absorbing particles to adhere to the natural fibers. Furthermore, method (d) can be applied to synthetic fibers, semi-synthetic fibers, regenerated fibers, inorganic fibers, or blends, doubling, or mixed fibers thereof, in addition to the natural fibers described above.

[0197] When carrying out the methods (a) to (d), the method for dispersing the organic-inorganic hybrid infrared-absorbing particles in the dispersion medium (solvent) is not particularly limited, and any method that can uniformly disperse the organic-inorganic hybrid infrared-absorbing particles in the liquid, i.e., the dispersion medium, can be used. For example, methods such as a medium stirring mill, a ball mill, a sand mill, and ultrasonic dispersion can be suitably used.

[0198] The dispersion medium for the organic-inorganic hybrid infrared-absorbing particles is not particularly limited and can be selected according to the fibers to be mixed. For example, one or more types selected from various common organic solvents such as alcohols, ethers, esters, ketones, and aromatic compounds, and water can be used.

[0199] Furthermore, when the organic-inorganic hybrid infrared-absorbing particles are attached to or mixed with fibers or the polymers that are their raw materials, a dispersion of the organic-inorganic hybrid infrared-absorbing particles may be directly mixed with the fibers or the polymers that are their raw materials. If necessary, the pH of the dispersion of the organic-inorganic hybrid infrared-absorbing particles may be adjusted by adding an acid or alkali to the dispersion, and various surfactants, coupling agents, etc. may also be added to further improve the dispersion stability of the organic-inorganic hybrid infrared-absorbing particles.

[0200] The content of the organic-inorganic hybrid infrared-absorbing particles contained in the infrared-absorbing fiber of this embodiment is not particularly limited. For example, the content of the organic-inorganic hybrid infrared-absorbing particles in the infrared-absorbing fiber of this embodiment is preferably 0.001% by mass or more and 80% by mass or less. Furthermore, when taking into consideration the weight of the infrared-absorbing fiber after the addition of the organic-inorganic hybrid infrared-absorbing particles and the raw material cost, the content of the organic-inorganic hybrid infrared-absorbing particles in the infrared-absorbing fiber is more preferably 0.005% by mass or more and 50% by mass or less.

[0201] When the content of the organic-inorganic hybrid infrared-absorbing particles in the infrared-absorbing fiber is 0.001% by mass or more, a sufficient infrared absorbing effect can be obtained even if the fabric using the infrared-absorbing fiber is thin.

[0202] Furthermore, if the content of the organic-inorganic hybrid infrared-absorbing particles in the infrared-absorbing fiber is 80% 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-absorbing particles added can be small, and the physical properties of the fiber are hardly impaired.

[0203] As explained above, the infrared-absorbing fiber according to this embodiment can provide a fiber with excellent heat retention, by disposing infrared-absorbing particles inside or on the surface of the fiber, which efficiently absorbs infrared rays from sunlight and the like. Furthermore, the infrared-absorbing fiber according to this embodiment has high chemical resistance, so its infrared absorption properties do not deteriorate even when exposed to a chemical environment containing high-temperature acids or alkalis. As a result, the infrared-absorbing fiber according to this embodiment can be used in a variety of applications, such as textile products that require heat retention, such as cold weather clothing, sports clothing, stockings, curtains, and other industrial textile products. [Textile products] The textile product of this embodiment is produced by processing the infrared absorbing fiber described above and may contain the infrared absorbing fiber described above. Note that the textile product of this embodiment may also be made of the infrared absorbing fiber described above.

[0204] The textile product of this embodiment containing the above-mentioned infrared-absorbing fiber has excellent properties, with a visible light absorptance of 20% or less and a solar radiation absorptance of 57% or more. A visible light absorptance of 20% or less and a solar radiation absorptance of 57% or more means that the textile product is light in color and has a superior infrared absorption effect.

[0205] The textile product of this embodiment containing the infrared-absorbing fiber of this embodiment has excellent chemical resistance, and for example, even when immersed for 30 minutes in a 0.01 mol / L aqueous sodium hydroxide solution maintained at 80° C., the solar absorptance remains at 57% or more. In other words, the textile product of this embodiment has chemical resistance. [Example]

[0206] The present invention will be specifically described below with reference to examples, although the present invention is not limited to the following examples.

[0207] The optical properties of the textile products obtained in the examples and comparative examples were measured using a spectrophotometer U-4100 (manufactured by Hitachi, Ltd.) Visible light transmittance, visible light reflectance, solar transmittance, and solar reflectance were measured in accordance with JIS R 3106 (2019).

[0208] The crystallite size of the infrared-absorbing particles was measured using a dry powder of infrared-absorbing particles obtained by removing the solvent from a dispersion of the infrared-absorbing particles. The X-ray diffraction pattern of the infrared-absorbing particles was measured by powder X-ray diffraction (θ-2θ method) using a powder X-ray diffractometer (X'Pert-PRO / MPD manufactured by PANalytical, Spectris Co., Ltd.). The crystalline structure contained in the infrared-absorbing particles was identified from the obtained X-ray diffraction pattern, and the crystallite size was calculated using the Rietveld method.

[0209] In addition, the particle size distribution based on scattering intensity was measured for the mini-emulsion obtained in the stirring process and the organic-inorganic hybrid infrared-absorbing particles obtained after the polymerization process using a particle size measuring device based on dynamic light scattering (ELSZ-2000 manufactured by Otsuka Electronics Co., Ltd.), and D50 and standard deviation were calculated. [Example 1] Infrared absorbing fibers and textile products were prepared and evaluated according to the following procedures. 1. Production of organic-inorganic hybrid infrared absorbing particles Organic-inorganic hybrid infrared absorbing particles for use in infrared absorbing fibers were produced according to the following steps. (Dispersion liquid preparation process) In the dispersion liquid preparation step, a dispersion liquid containing infrared absorbing particles, a dispersant, and a dispersion medium was prepared.

[0210] The infrared absorbing particles are hexagonal cesium tungsten bronze (Cs), with a mass ratio of cesium (Cs) to tungsten (W) of Cs / W = 0.33. 0.33 WO z A composite tungsten oxide powder (YM-01 manufactured by Sumitomo Metal Mining Co., Ltd.) containing tungsten oxide (2.0≦z<4.0) was prepared.

[0211] As the dispersant, a polymer dispersant, which is a copolymer of styrene and 2-(dimethylamino)ethyl methacrylate, was prepared.

[0212] Toluene was used as the dispersion medium.

[0213] Then, a mixture obtained by mixing 20 mass% of infrared absorbing particles, 3 mass% of dispersant, and 77 mass% of dispersion medium was loaded into a paint shaker containing 0.3 mmφ ZrO2 beads and subjected to a pulverization and dispersion treatment for 21 hours to obtain Cs according to Example 1. 0.33 WO z A dispersion of particles was obtained. (Dispersion medium reduction process) Cs obtained in the dispersion preparation process 0.33 WO zThe dispersion medium, toluene, was removed from the particle dispersion using an evaporator, and the infrared absorbing particles were recovered. The recovered infrared absorbing particles were Cs containing a polymer dispersant. 0.33 WO z The particles become a dry powder.

[0214] The recovered infrared absorbing particles, namely Cs 0.33 WO z The crystallite diameter of the particles was measured to be 16 nm.

[0215] The crystallite diameter was measured and calculated by the method already described. (Raw material mixture preparation process) 13.2 g of the infrared absorbing particles obtained in the dispersion medium reduction step, 10 g of styrene as a raw material for the coating resin, 0.5 g of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 0.7 g of hexadecane as an organic solvent were mixed to form an organic phase.

[0216] Separately from the organic phase, 1.0 g of dodecyltrimethylammonium chloride as an emulsifier and 100 g of water were mixed to form an aqueous phase.

[0217] Thereafter, the organic phase was added to the aqueous phase to prepare a raw material mixture. (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 mini-emulsion measured by dynamic light scattering showed a single peak. At this time, the particle size distribution had a D50 of 188 nm and a standard deviation of 119. (Polymerization process) After the stirring step, the raw material mixture was subjected to nitrogen bubbling in an ice bath for 15 minutes to perform deoxidation treatment.

[0218] Thereafter, the mixture was heated at 70°C for 6 hours in a nitrogen atmosphere to promote the polymerization reaction of styrene, thereby obtaining a dispersion containing organic-inorganic hybrid infrared-absorbing particles.

[0219] The obtained dispersion containing the organic-inorganic hybrid infrared-absorbing particles was diluted and transferred to a microgrid for TEM observation, and the transferred product was observed by TEM. The TEM image is shown in Figure 4. From the TEM image, it was confirmed that particles containing composite tungsten oxide, which are infrared-absorbing particles 401 and appear black, are encapsulated in a coating of polystyrene resin, which is coating resin 402 and appear gray, forming organic-inorganic hybrid infrared-absorbing particles 40. Note that the microgrid 41 in the TEM image in Figure 4 does not constitute organic-inorganic hybrid infrared-absorbing particles.

[0220] The content of infrared absorbing particles in the organic-inorganic hybrid infrared absorbing particles obtained in Example 1 was 45.4% by mass. To calculate the content of infrared absorbing particles in the organic-inorganic hybrid infrared absorbing particles, the organic-inorganic hybrid infrared absorbing particles were subjected to TGA (thermogravimetry), and the resin component was removed by heating until the weight loss stopped, and the mass of the infrared absorbing particles in the obtained organic-inorganic hybrid infrared absorbing particles was measured. The content of the measured infrared absorbing particles in the organic-inorganic hybrid infrared absorbing particles used for evaluation was then calculated. Calculations were made in the same manner in the other examples and comparative examples below.

[0221] Furthermore, the obtained organic-inorganic hybrid infrared-absorbing particles had one peak in the particle size distribution based on scattering intensity measured by a dynamic light scattering method, and the D50 calculated from the particle size distribution was 188 nm and the standard deviation was 119. 2. Manufacturing of infrared absorbing fibers The obtained dispersion containing the organic-inorganic hybrid infrared-absorbing particles was mixed with a water-soluble acrylic binder resin to prepare a treatment liquid. Next, a polyester fiber was impregnated with the treatment liquid and dried to produce the infrared-absorbing fiber according to Example 1 to which the organic-inorganic hybrid infrared-absorbing particles were attached. 3. Textile manufacturing The obtained infrared-absorbing fiber was cut to prepare polyester staples, which were then used to produce spun yarn. This spun yarn was then used to obtain the knit product of Example 1. The solar absorptance of the produced knit product sample was adjusted to be around 60%. Similar adjustments were made in the other examples and comparative examples below. 4. Evaluation of textile products The optical properties of the textile product according to Example 1 were measured by the above-mentioned method. The visible light absorptance and solar radiation absorptance were calculated from the following equation: visible light absorptance (%) = 100% - visible light transmittance (%) - visible light reflectance (%) and solar radiation absorptance (%) = 100% - solar radiation transmittance (%) - solar radiation reflectance (%). The calculated visible light absorptance and solar radiation absorptance were 20% and 60%, respectively. Furthermore, when the color tone of the knitted product was visually confirmed, it was found to be light in color. 5. Evaluation of alkali resistance properties An alkalinity test was carried out by immersing the textile product of Example 1 in a 0.01 mol / L aqueous solution of sodium hydroxide maintained at 80° C. for 30 minutes, after which the optical properties were measured again.

[0222] The visible light absorptance and solar radiation absorptance after the alkaline test were 20% and 60%, respectively. When comparing the visible light absorptance and solar radiation absorptance before and after the alkaline test, the difference was 0% in both cases. The evaluation results are shown in Table 1.

[0223] That is, it was confirmed that there was no significant change in the light absorptance of the infrared absorbing fiber before and after the alkaline test. Therefore, it was confirmed that the infrared absorbing fiber and the textile product obtained in this example have chemical resistance, particularly alkali resistance. [Example 2] In the raw material mixture preparation step, 4.0 g of the infrared absorbing particles obtained in the dispersion medium reduction step of Example 1, 16 g of styrene as a coating resin raw material, 0.8 g of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 1.0 g of hexadecane as an organic solvent were mixed to form an organic phase.

[0224] In addition to the organic phase, 0.5 g of cetyltrimethylammonium chloride as an emulsifier and 80 g of water were mixed to form an aqueous phase. Except for the above, the infrared-absorbing fiber and textile product of Example 2 were obtained in the same manner as in Example 1.

[0225] The content of the infrared absorbing particles in the organic-inorganic hybrid infrared absorbing particles obtained in Example 2 was 16.0% by mass.

[0226] Furthermore, in the stirring step, the raw material mixture was stirred in an ice bath until the particle size distribution of the resulting mini-emulsion based on scattering intensity measured by dynamic light scattering showed a single peak, and the D50 and standard deviation were the same as those in Example 1. Furthermore, the particle size distribution of the resulting organic-inorganic hybrid infrared-absorbing particles based on scattering intensity measured by dynamic light scattering showed a single peak, and the D50 and standard deviation were also the same as those in Example 1.

[0227] The obtained textile product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. [Comparative Example 1] In the dispersion liquid preparation step, a dispersion liquid containing infrared absorbing particles and a dispersion medium was prepared.

[0228] The infrared absorbing particles are hexagonal cesium tungsten bronze (Cs), with a mass ratio of cesium (Cs) to tungsten (W) of Cs / W = 0.33. 0.33 WO z A composite tungsten oxide powder (YM-01 manufactured by Sumitomo Metal Mining Co., Ltd.) containing tungsten oxide (2.0≦z<4.0) was prepared.

[0229] As the dispersion medium, pure water was prepared.

[0230] Then, a mixture obtained by mixing 10 mass % of the infrared absorbing particles and 90 mass % of the dispersion medium was loaded into a paint shaker containing 0.3 mm diameter ZrO2 beads and subjected to a pulverization and dispersion treatment for 10 hours. 0.33 WO zA dispersion of particles was obtained.

[0231] Cs obtained in the dispersion preparation process 0.33 WO z The pure water dispersion medium was removed from the particle dispersion using an evaporator, and the infrared absorbing particles were recovered. 0.33 WO z The particles become a dry powder.

[0232] The recovered infrared absorbing particles, namely Cs 0.33 WO z The crystallite diameter of the particles was measured to be 16 nm.

[0233] The crystallite diameter was measured and calculated by the method already described.

[0234] Instead of the dispersion liquid containing the organic-inorganic hybrid infrared-absorbing particles of Example 1, Cs according to Comparative Example 1 prepared in the above dispersion liquid preparation step was used. 0.33 WO z The same operations as in Example 1 were carried out except that a particle dispersion liquid was used, to obtain an infrared absorbing fiber and a textile product according to Comparative Example 1. The obtained textile product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. Comparative Example 2 In the raw material mixture preparation step, 3.9 g of the infrared absorbing particles obtained in the dispersion medium reduction step of Example 1, 20.9 g of styrene as a coating resin raw material, 0.8 g of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 2.0 g of hexadecane as an organic solvent were mixed to form an organic phase.

[0235] In addition to the organic phase, 0.5 g of cetyltrimethylammonium chloride as an emulsifier and 80 g of water were mixed to form an aqueous phase. Except for the above, the infrared absorbing fiber and textile product according to Comparative Example 2 were obtained in the same manner as in Example 1.

[0236] The content of the infrared absorbing particles in the organic-inorganic hybrid infrared absorbing particles obtained in Comparative Example 2 was 12.7% by mass.

[0237] The obtained textile product was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1. Comparative Example 3 In the raw material mixture preparation step, 3.9 g of the infrared absorbing particles obtained in the dispersion medium reduction step of Example 1, 0.8 g of styrene as a coating resin raw material, 0.8 g of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 2.0 g of hexadecane as an organic solvent were mixed to form an organic phase.

[0238] Separately from the organic phase, 0.5 g of cetyltrimethylammonium chloride as an emulsifier and 80 g of water were mixed to form an aqueous phase.

[0239] After that, the organic phase was added to the aqueous phase to prepare a raw material mixture, but gelation occurred and the organic-inorganic hybrid infrared-absorbing particles could not be obtained.

[0240] [Table 1] From the results of the evaluation of the optical properties of the textile products before and after the alkaline test shown in Table 1 above, it was confirmed that there was no significant change in the light absorption properties before and after the test for the textile products using the organic-inorganic hybrid infrared-absorbing particles of each Example, in which a coating resin was disposed on at least a part of the surface of the infrared-absorbing particles.

[0241] Therefore, it was confirmed that the infrared-absorbing fibers using the organic-inorganic hybrid infrared-absorbing particles of each Example and the textile products containing the infrared-absorbing fibers have excellent alkali resistance, i.e., chemical resistance, and also excellent infrared absorption properties. Although only an alkali test was conducted here, these organic-inorganic hybrid infrared-absorbing particles also have acid resistance because the coating resin is disposed on at least a portion of the surface of the infrared-absorbing particles.

[0242] On the other hand, the textile product using the infrared absorbing particles of Comparative Example 1 lost its infrared absorbing properties after the alkaline test, confirming that it did not have alkali resistance. Furthermore, the textile product using the infrared absorbing particles of Comparative Example 2 could not achieve a solar absorptance of around 60%. Furthermore, gelation occurred in the raw material mixture preparation step in Comparative Example 3, and the organic-inorganic hybrid infrared absorbing particles and textile products could not be produced.

[0243] This application claims priority based on Patent Application No. 2021-165319 filed with the Japan Patent Office on October 7, 2021, and the entire contents of Patent Application No. 2021-165319 are incorporated by reference into this international application. [Explanation of symbols]

[0244] 20, 32, 40 Organic-inorganic hybrid infrared absorbing particles 21,401 Infrared absorbing particles 22, 402 Coating resin 221 Resin Capsule 30 Infrared absorbing fiber 31 Fiber 31A surface 31B Internal

Claims

1. Fiber and and organic-inorganic hybrid infrared absorbing particles, the organic-inorganic hybrid infrared-absorbing particles comprise infrared-absorbing particles and a coating resin covering at least a part of the surface of the infrared-absorbing particles, the content of the infrared-absorbing particles being 15% by mass or more and 55% by mass or less, the particles having one peak in a particle size distribution based on scattering intensity measured by a dynamic light scattering method, and a median diameter of 800 nm or less, The infrared absorbing particles are selected from the group consisting of tungsten oxide represented by the general formula WyOz (W: tungsten, O: oxygen, 2.2≦z / y≦2.999), tungsten oxide represented by the general formula MxWyOz (element M is H, He, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, one or more elements selected from Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Hf, Os, Bi, and I; and one or more elements selected from composite tungsten oxides represented by the formula: 0.001≦x / y≦1, 2.0≦z / y<4.0), The organic-inorganic hybrid infrared absorbing particles are disposed in one or more portions selected from the interior and the surface of the fiber.

2. 2. The infrared-absorbing fiber according to claim 1, wherein the coating resin comprises one or more resins selected from the group consisting of 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.

3. 3. The infrared absorbing fiber 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.

4. 3. The infrared absorbing fiber according to claim 1, wherein the fiber comprises at least one type selected from the group consisting of synthetic fibers, semi-synthetic fibers, natural fibers, regenerated fibers, and inorganic fibers.

5. 5. The infrared absorbing fiber according to claim 4, wherein the synthetic fiber comprises 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.

6. 5. The infrared absorbing fiber according to claim 4, 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.

7. 5. The infrared absorbing fiber according to claim 4, wherein the natural fibers include at least one type selected from the group consisting of plant fibers, animal fibers, and mineral fibers.

8. 5. The infrared absorbing fiber according to claim 4, wherein the regenerated fiber comprises at least one fiber selected from the group consisting of cellulose-based fiber, protein-based fiber, alginate fiber, rubber fiber, chitin fiber, and mannan fiber.

9. 5. The infrared absorbing fiber according to claim 4, wherein the inorganic fiber comprises at least one type selected from the group consisting of metal fiber, carbon fiber, and silicate fiber.

10. A textile product comprising the infrared-absorbing fiber according to claim 1 or 2.

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