TWI888540B - Fiber products - Google Patents

Abstract

Provided is an infrared absorbing fiber, comprising: fiber; and organic-inorganic hybrid infrared absorbing particles, the organic-inorganic hybrid infrared absorbing particles having infrared absorbing particles and a coating resin covering at least a portion of the surface of the infrared absorbing particles, the organic-inorganic hybrid infrared absorbing particles being arranged in one or more portions selected from the interior and the surface of the fiber.

Description

Fiber products

The present invention relates to infrared absorbing fibers and fiber products.

Various cold-weather clothing, interior decoration, and leisure products that have improved thermal insulation effects have been studied and put into practical use. So far, the methods of improving the thermal insulation effects that have been put into practical use can be roughly divided into two methods.

The first method is to reduce the heat dissipation generated from the human body to maintain thermal insulation. Specifically, for example, a method is adopted to physically increase the air layer in the cold-proof clothing by controlling the weaving structure in the cold-proof clothing or making the fibers used hollow or porous.

The second method is to radiate the heat generated by the human body back to the human body, convert part of the sunlight received by the cold-proof clothing into heat, and store heat to improve thermal insulation. Specifically, for example, in cold-proof clothing, a method of chemically and physically processing the entire clothing or the fibers constituting the cold-proof clothing is adopted.

As mentioned above, as the first method, a method of increasing the air layer in the clothes, thickening the fabric, making the mesh finer, or darkening the color is adopted. As a specific example, winter clothes such as sweaters, which are widely used as clothes for winter sports, are filled with cotton between the fabric and the lining, and the thickness of the air layer of the cotton is used to maintain heat retention. However, if the air layer is increased by adding cotton, the clothes become heavier, which causes disadvantages when facing sports that require easy movement. In order to eliminate such disadvantages, in recent years, a method of actively and effectively utilizing the heat generated from the inside and the outside has begun to be adopted as the second method mentioned above.

As a method of implementing the second method, it is known to evaporate metals such as aluminum and titanium to the inside of clothes, etc., and reflect the radiant heat from the body on the metal evaporation surface to actively prevent the heat from radiating. However, in such a method, it costs a lot to evaporate the metal for clothes, and the yield rate is reduced due to the occurrence of evaporation spots, etc., resulting in an increase in the price of the product itself.

In addition, as another method for implementing the second method, a method of mixing ceramic particles such as aluminum oxide, zirconium oxide, and magnesium oxide into the fiber itself and utilizing the far-infrared radiation effect and the effect of converting light into heat possessed by these ceramic particles has been proposed, that is, a method of actively using external energy.

For example, Patent Document 1 discloses a heat radiating fiber characterized by containing one or more inorganic particles having heat radiating properties, including at least one metal or metal ion having a thermal conductivity of 0.3 kcal/m ² ‧sec‧℃ or more. Examples of the inorganic particles having heat radiating properties include silicon dioxide and barium sulfate.

Patent document 2 discloses a heat-retaining composite fiber, which is characterized in that it is a composite fiber containing a thermoplastic polymer A with a melting point of 110°C or above, and a thermoplastic polymer B with a melting point of 15-50°C, a cooling crystallization temperature of 40°C or below, and a crystallization heat of 10mJ/mg or above, and contains 0.1-20% by weight of ceramic particles with far-infrared radiation ability relative to the weight of the fiber, and the polymer A covers the fiber surface.

Patent document 3 discloses an infrared absorbing processed fiber product in which a binder resin containing an infrared absorber formed of at least one specified amino compound is dispersed and adhered in the fiber product.

Patent document 4 discloses a near-infrared absorption processing method for a cellulose-based fiber structure, in which a dye having a characteristic of greater absorption in the near-infrared region than a black dye is combined with other dyes to achieve a near-infrared absorption degree of 65% or less in the range of 750 to 1500 nm for the spectral reflectance of the fabric.

In addition, the applicant of the present invention proposed fibers containing boride particles, tungsten oxide particles, and composite tungsten oxide particles, as well as fiber products obtained by processing the fibers in patent documents 5, 6, and 7.

[Prior Art Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 11-279830

[Patent Document 2] Japanese Patent Publication No. 5-239716

[Patent Document 3] Japanese Patent Publication No. 8-3870

[Patent Document 4] Japanese Patent Publication No. 9-291463

[Patent Document 5] Japanese Patent Publication No. 2005-9024

[Patent Document 6] Japanese Patent Publication No. 2006-132042

[Patent Document 7] International Publication No. 2019/054476

For example, as disclosed in patent documents 5 to 7, infrared absorbing fibers containing infrared absorbing particles have been studied. However, according to the research of the inventors of the present invention, infrared absorbing particles such as tungsten oxide particles have insufficient chemical resistance, and infrared absorbing fibers and fiber products may have reduced infrared absorbing properties when exposed to a chemical environment such as high-temperature acid or alkali.

In one embodiment of the present invention, an object is to provide an infrared absorbing fiber having chemical resistance.

In one embodiment of the present invention, an infrared absorbing fiber is provided, comprising: a fiber; and organic-inorganic hybrid infrared absorbing particles, wherein the organic-inorganic hybrid infrared absorbing particles have infrared absorbing particles and a coating resin covering at least a portion of the surface of the infrared absorbing particles, and the organic-inorganic hybrid infrared absorbing particles are arranged in one or more portions selected from the interior and the surface of the fiber.

In one embodiment of the present invention, infrared absorbing fibers having chemical resistance can be provided.

10: Unit lattice

11: Octahedron formed by WO ₆ units

12: Gap

121: As an element of element M

21: Particles

22: membrane

23: Organic-inorganic hybrid infrared absorbing particles

24: Microgrid

[Figure 1] is a schematic diagram of the crystal structure of a complex tungsten oxide having hexagonal crystals.

[Figure 2] is a transmission electron microscope photograph of the organic-inorganic hybrid infrared absorbing particles obtained in Example 1.

[Infrared absorbing fibers]

In this embodiment, an example of the structure of infrared absorbing fiber is described.

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

Furthermore, the organic-inorganic hybrid infrared absorbing particles can have infrared absorbing particles and a coating resin that covers at least a portion of the surface of the infrared absorbing particles.

Furthermore, the organic-inorganic hybrid infrared absorbing particles can be arranged in one or more parts selected from the interior and the surface of the fiber.

As described above, infrared absorbing particles used in infrared absorbing fibers sometimes have insufficient chemical resistance. Therefore, the inventors of the present invention have conducted in-depth research on methods for making infrared absorbing particles with chemical resistance. As a result, it was found that organic materials such as resins are directly arranged on at least a portion of the surface of infrared absorbing particles to make organic-inorganic hybrid infrared absorbing particles, thereby being able to exert chemical resistance.

However, infrared absorbing particles are usually inorganic materials, and it is difficult to configure organic materials such as resin on at least a part of their surface. Therefore, organic-inorganic hybrid infrared absorbing particles and their manufacturing methods are still unknown. Therefore, the inventors of the present invention conducted further research and found organic-inorganic hybrid infrared absorbing particles with organic materials configured on the surface of infrared absorbing particles and their manufacturing methods.

Furthermore, it was found that by using such organic-inorganic hybrid infrared absorbing particles, infrared absorbing fibers having chemical resistance could be produced, thereby completing the present invention.

Therefore, first, the manufacturing method of organic-inorganic hybrid infrared absorbing particles and the organic-inorganic hybrid infrared absorbing particles are explained.

1. Method for manufacturing organic-inorganic hybrid infrared absorbing particles

As already described, the infrared absorbing fiber of this embodiment can contain organic-inorganic hybrid infrared absorbing particles. Moreover, the method for producing such organic-inorganic hybrid infrared absorbing particles can have, for example, the following steps.

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

A dispersion medium reduction step that allows the dispersion medium to evaporate from the dispersion liquid.

After the dispersion medium reduction step, the recovered infrared absorbing particles, the coating resin raw material, the organic solvent, the emulsifier, the water and the polymerization initiator are mixed to prepare the raw material mixed solution.

While cooling the raw material mixture, a stirring step is performed.

After deoxygenation treatment to reduce the oxygen content in the raw material mixture, a polymerization step of the coating resin raw material is performed.

The following describes each step.

(1) Dispersion preparation steps

In the dispersion preparation step, a dispersion containing infrared absorbing particles, a dispersant and a dispersion medium can be prepared.

Describe the materials that can be used appropriately in preparing the dispersion in the dispersion preparation step.

(a) Infrared absorbing particles

In the dispersion preparation step, various infrared absorbing particles that require improved chemical resistance, such as acid resistance and alkali resistance, can be used as infrared absorbing particles. It is preferred to use infrared absorbing particles containing various materials such as free electrons as infrared absorbing particles, and it is more preferred to use infrared absorbing particles containing various inorganic materials containing free electrons.

As the infrared absorbing particles, infrared absorbing particles containing one or more selected from tungsten oxides and composite tungsten oxides having oxygen defects can be particularly preferably used. When tungsten oxides and composite tungsten oxides having oxygen defects are used as infrared absorbing particles, organic-inorganic hybrid infrared absorbing particles containing the infrared absorbing particles can be made light-colored and inconspicuous. In this case, specifically, the infrared absorbing particles preferably contain tungsten _oxides selected from, for example, those represented by the general formula _WyOz (W: tungsten, O: oxygen, 2.2≦ _z /y _≦ 2.999) and those represented by the general formula _MxWyOz (the element M is one or more selected from H, He, alkali metals, alkali earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I, 0.001≦x/y≦1, 2.0≦z/y≦3.0) of the composite tungsten oxide.

Generally speaking, it is known that materials containing free electrons show reflection and absorption responses to electromagnetic waves around the region of sunlight with a wavelength of 200nm to 2600nm through plasma oscillation. Therefore, various materials containing free electrons can be suitable for use as infrared absorbing particles. If infrared absorbing particles become particles smaller than the wavelength of light, for example, they can reduce geometric scattering in the visible light region (wavelength 380nm to 780nm), and can obtain particularly high transparency in the visible light region, so they are preferred.

In addition, the term "transparency" in this manual is used to mean "less scattering and higher transmittance relative to light in the visible light region."

Generally speaking, there are no effective free electrons in tungsten oxide (WO ₃ ), and therefore tungsten oxide has little absorption and reflection properties in the infrared region, and is not effective as infrared absorbing particles.

On the other hand, WO ₃ having oxygen defects and complex tungsten oxides in which positive elements such as Na are added to WO ₃ are known to be conductive materials and materials having free electrons. Furthermore, analysis of single crystals of these materials having free electrons has suggested that free electrons respond to infrared light.

According to the research of the inventors of the present invention, it is possible to obtain tungsten oxide and composite tungsten oxide that have a particularly effective range as an infrared absorbing material in a specific part of the composition range of tungsten and oxygen, are transparent in the visible light region, and have particularly strong absorption in the infrared region.

Therefore, tungsten oxide and composite tungsten oxide, which are a type of material for infrared absorbing particles that can be used appropriately in the dispersion preparation step, are further described below.

(a1)Tungsten oxide

Tungsten oxide is expressed by the general formula W _y O _z (wherein W is tungsten, O is oxygen, and 2.2≦z/y≦2.999).

In the tungsten oxide represented by _the general formula _WyOz , the composition range of tungsten and oxygen is such that the composition ratio (z/y) of oxygen to tungsten is preferably less than 3, more preferably 2.2≦z/y≦2.999, and particularly preferably 2.45≦z/y≦2.999.

When the value of z/y is 2.2 or more, the unintended WO ₂ crystal phase can be avoided in the tungsten oxide, and chemical stability as a material can be obtained, thereby becoming a particularly effective infrared absorbing particle.

Furthermore, by making the value of z/y preferably less than 3, and more preferably less than 2.999, the absorption-reflection characteristics in the infrared region are improved, and a particularly sufficient amount of free electrons is generated, so that infrared absorbing particles can be efficiently produced.

In addition, the so-called "Magneli phase" having a composition ratio of 2.45≦z/y≦2.999 is chemically stable and has excellent absorption properties for near-infrared light, so it can be more preferably used as an infrared absorption material. Therefore, the above z/y is further preferably 2.45≦z/y≦2.999 as already described.

(a2) Complex tungsten oxide

The composite tungsten oxide is a product obtained by adding the element M described later to the above WO ₃ .

By adding the element M to form a composite tungsten oxide, free electrons are generated in WO ₃ , and strong absorption characteristics derived from free electrons are exhibited, especially in the near-infrared region, making it effective as a particle that absorbs near-infrared rays with a wavelength of around 1000nm.

That is, by producing a composite tungsten oxide in which the amount of oxygen is controlled and an element M that generates free electrons is added to WO ₃ , the infrared absorption characteristics can be more efficiently exerted. When the general formula of the composite tungsten oxide in which the amount of oxygen is controlled and an element M that generates free electrons is added to WO ₃ is expressed as M _x W _y O _z , it is preferred to satisfy the relationship of 0.001 ≦ x/y ≦ 1, 2.0 ≦ z/y ≦ 3.0. In the above general formula, M represents the element M described above, W represents tungsten, and O represents oxygen.

As described above, when the value of x/y representing the addition amount of element M is 0.001 or more, a particularly sufficient amount of free electrons can be generated in the composite tungsten oxide, and a high infrared absorption effect can be obtained. Moreover, the more the addition amount of element M is, the more the supply of free electrons increases, and the infrared absorption efficiency also increases, but the effect is also saturated when the value of x/y is about 1. In addition, when the value of x/y is less than 1, it is possible to avoid the generation of impurity phases in the infrared absorption particles containing the composite tungsten oxide, so it is preferred.

In addition, the element M is preferably one or more selected from H, He, alkali metals, alkali earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I.

From the viewpoint of particularly improving the stability in _MxWyOz , the element M is more preferably one or more elements selected from alkali metals, alkali earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, _Ru , _Co , Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, and Re. Furthermore, from the viewpoint of improving the optical properties and weather resistance of the infrared absorbing particles containing the composite tungsten oxide, the element M is further preferably one or more elements selected from alkali metals, alkali earth metal elements, transition metal elements, 4B group elements, and 5B group elements.

Regarding the value of z/y indicating the amount _of oxygen added, in the composite tungsten oxide represented by _MxWyOz , in addition to the same mechanism as that _of the tungsten oxide represented _{by WyOz} , free electrons are supplied by the amount of addition of the element M at z/y=3.0. Therefore, 2.0≦z/y≦3.0 is preferred, 2.2≦z/y≦3.0 is more preferred, and 2.45≦z/y≦3.0 is further preferred.

Furthermore, when the composite tungsten oxide has a hexagonal crystal structure, the infrared absorbing particles containing the composite tungsten oxide have improved transmittance of light in the visible light region and improved absorption of light in the infrared region. This is explained with reference to FIG1 which is a schematic plan view of the hexagonal crystal structure.

FIG1 shows a projection diagram of the crystal structure of a complex tungsten oxide having a hexagonal crystal structure when observed from the (001) direction, with the unit cell 10 represented by a dotted line.

In FIG. 1 , six octahedrons 11 formed of WO ₆ units are assembled to form a hexagonal void 12. In the void 12, an element 121 as the element M is arranged to form one unit. A plurality of the units are assembled to form a hexagonal crystal structure.

Furthermore, in order to increase the transmission of light in the visible light region and the absorption of light in the infrared region, the composite tungsten oxide only needs to include the unit structure described using FIG. 1, and the composite tungsten oxide may be crystalline or amorphous.

When cations of element M are added and present in the above-mentioned hexagonal voids, the transmission of light in the visible light region is improved, and the absorption of light in the infrared region is improved. Generally speaking, when an element M with a large ion radius is added, the hexagonal crystal is easily formed. Specifically, when one or more selected from Cs, K, Rb, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn are added as the element M, hexagonal crystal is easily formed. Of course, even if it is an element other than these, as long as the above-mentioned element M exists in the hexagonal voids formed by the WO ₆ unit, it is not limited to the above-mentioned elements.

The composite tungsten oxide having a hexagonal crystal structure has a uniform crystal structure, so the amount of element M added is preferably 0.2 or more and 0.5 or less, and more preferably 0.33, based on the value of x/y in the general formula already described. It is believed that by setting the value of x/y to 0.33, the element M is arranged in all the gaps of the hexagon.

In addition, infrared absorbing particles of composite tungsten oxides including tetragonal and cubic crystals in addition to hexagonal crystals also have sufficiently effective infrared absorption characteristics. Depending on the crystal structure, there is a tendency for the absorption position in the infrared region to change, and there is a tendency for the absorption position to shift to the long wavelength side in the order of cubic crystal <tetragonal crystal <hexagonal crystal. In addition, along with this, the absorption of light in the visible light region is less in the order of hexagonal crystal, tetragonal crystal, and cubic crystal. Therefore, in the use of transmitting more light in the visible light region and shielding more light in the infrared region, it is preferred to use hexagonal composite tungsten oxide. However, the tendency of the optical characteristics described here is a rather rough tendency, which changes according to the type, amount, and oxygen amount of the added element, and the present invention is not limited to this.

Infrared absorbing particles containing tungsten oxide and composite tungsten oxide greatly absorb light in the near-infrared region, especially light with a wavelength of around 1000nm, so most of them have a transmission color tone ranging from blue to green.

In addition, the dispersed particle size of the infrared absorbing particles can be selected according to their purpose of use.

First, when used in applications where transparency is to be maintained, infrared absorbing particles preferably have a dispersed particle size of 800nm or less. This is because particles with a dispersed particle size of 800nm or less are not scattered and completely shield light, and can maintain visibility in the visible light region while efficiently maintaining transparency. In particular, when transparency in the visible light region is important, it is further preferred to consider the reduction of scattering caused by the particles.

When the reduction of scattering caused by particles is important, the dispersed particle size is preferably 200nm or less, and more preferably 100nm or less. This is because, if the dispersed particle size of the particles is small, the scattering of light in the visible light region with a wavelength of 400nm or more and 780nm or less due to geometric scattering or Mie scattering can be reduced, and as a result, it is possible to avoid, for example, the infrared absorbing film dispersed with infrared absorbing particles becoming a cloudy glass and failing to obtain clear transparency. That is, if the dispersed particle size is 200nm or less, the above-mentioned geometric scattering or Mie scattering is reduced, and it becomes a Rayleigh scattering region. This is because in the Rayleigh scattering region, the scattered light decreases in proportion to the sixth power of the particle size, so as the dispersed particle size decreases, the scattering decreases and the transparency improves.

Furthermore, if the dispersed particle size is less than 100nm, the scattered light becomes very small, which is preferred. From the perspective of avoiding light scattering, a small dispersed particle size is preferred.

There is no particular lower limit on the dispersed particle size of the infrared absorbing particles. For example, since they can be easily manufactured industrially, the dispersed particle size is preferably greater than 1 nm.

By making the dispersed particle size of the infrared absorbing particles less than 800nm, the haze value of the infrared absorbing particle dispersion in which the infrared absorbing particles are dispersed in the medium can be made less than 85% of visible light transmittance and less than 30% of haze. By making the haze less than 30%, the infrared absorbing particle dispersion is prevented from becoming like hazy glass, and particularly clear transparency can be obtained.

In addition, the dispersed particle size of infrared absorbing particles can be measured using the ELS-8000 manufactured by Otsuka Electronics Co., Ltd., which uses the dynamic light scattering method as its principle.

In addition, from the perspective of exerting excellent infrared absorption characteristics, the crystallite diameter of the infrared absorbing particles is preferably 1 nm to 200 nm, more preferably 1 nm to 100 nm, and further preferably 10 nm to 70 nm. The crystallite diameter can be measured by measuring the X-ray diffraction pattern using the powder X-ray diffraction method (θ-2θ method) and analyzing it using the Riedbold method. The X-ray diffraction pattern can be measured using, for example, the powder X-ray diffraction device "X'Pert-PRO/MPD" manufactured by Spectris Co., Ltd. PANalytical.

(b) Dispersant

The dispersant is used for the purpose of hydrophobizing the surface of the infrared absorbing particles. The dispersant can be selected based on the dispersion system as a combination of infrared absorbing particles, dispersion medium, coating resin raw materials, etc. Among them, a dispersant having one or more selected from amino, hydroxyl, carboxyl, sulfonic, phosphonyl, and epoxy groups as functional groups can be suitably used. When the infrared absorbing particles are tungsten oxide or composite tungsten oxide, the dispersant preferably has an amino group as a functional group.

As described above, the dispersant is preferably an amine compound having an amine group as a functional group. In addition, the amine compound is more preferably a tertiary amine.

In addition, the dispersant is used for the purpose of hydrophobizing the surface of the infrared absorbing particles, so it is preferably a polymer material. Therefore, the dispersant preferably has one or more selected from, for example, a long-chain alkyl group and a benzene ring, and it is more preferably possible to use a polymer dispersant of a copolymer of styrene and 2-(dimethylamino)ethyl methacrylate as a tertiary amine, which can be used as a side chain resin raw material. The long-chain alkyl group is preferably an alkyl group with more than 8 carbon atoms. In addition, for example, it can also be used as a polymer material and as a dispersant for an amine compound.

The amount of dispersant added is not particularly limited and can be selected arbitrarily. The appropriate amount of dispersant added can be selected according to the dispersant, the type of infrared absorbing particles, the specific surface area of the infrared absorbing particles, etc. For example, if the amount of dispersant added is 10 parts by mass or more and 500 parts by mass or less relative to 100 parts by mass of infrared absorbing particles, it is easy to prepare a dispersion liquid with a particularly good dispersion state, so it is preferred. The amount of dispersant added is more preferably 10 parts by mass or more and 100 parts by mass or less, and further preferably 20 parts by mass or more and 50 parts by mass or less.

(c) Dispersion medium

The dispersion medium can be any dispersion medium that can disperse the infrared absorbing particles and the dispersant described above to prepare a dispersion liquid, and various organic compounds can be used, for example.

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

In the dispersion preparation step, the infrared absorbing particles, the dispersant and the dispersion medium are mixed to prepare the dispersion. In order to reduce the dispersed particle size of the infrared absorbing particles and evenly disperse them in the dispersion, it is preferred to perform a crushing process on the infrared absorbing particles during the mixing process.

There is no particular limitation on the mixing method used when mixing and pulverizing the infrared absorbing particles, the dispersant, and the dispersion medium. For example, one or more selected from a bead mill, a ball mill, a sand mill, a paint shaker, an ultrasonic homogenizer, etc. can be used. In particular, as the mixing method, a medium stirring mill such as a bead mill, a ball mill, a sand mill, a paint shaker, etc. using a medium such as beads, balls, or Ottawa sand is more preferably used. This is because the use of a medium stirring mill can produce the desired dispersed particle size for the infrared absorbing particles in a short time, which is preferred from the perspective of productivity and suppression of impurities.

(2) Dispersing medium reduction step

In the dispersion medium reduction step, the dispersion medium can be evaporated from the dispersion liquid and dried.

In the dispersion medium reduction step, it is preferred to allow the dispersion medium to be fully evaporated from the dispersion liquid to recover the infrared absorbing particles.

The specific method for evaporating the dispersion medium is not particularly limited, and for example, a dryer such as an oven, an evaporator, a vacuum flow dryer such as a vacuum pounder, a spray dryer such as a spray dryer, etc. can be used.

In addition, there is no particular limitation on the degree of evaporation of the dispersion medium, but it is preferred that the content ratio of the dispersion medium be sufficiently reduced in such a way as to obtain powdered infrared absorbing particles, for example, after the dispersion medium reduction step.

By evaporating the dispersion medium, the dispersant is arranged around the infrared absorbing particles, and the infrared absorbing particles with hydrophobic surface treatment can be obtained. Therefore, it is possible to improve the adhesion between the infrared absorbing particles treated with hydrophobicity and the coating resin obtained by polymerizing the coating resin raw material, and it is possible to arrange the coating resin on at least a part of the surface of the infrared absorbing particles through the polymerization step described later.

(3) Raw material mixture preparation step

In the raw material mixed solution preparation step, the infrared absorbing particles recovered after the dispersion medium reduction step, the coating resin raw material, the organic solvent, the emulsifier, the water and the polymerization initiator can be mixed to prepare the raw material mixed solution.

The infrared absorbing particles recovered after the dispersion medium reduction step sometimes have the dispersant supplied in the dispersion liquid preparation step attached to the surface of the particles, becoming infrared absorbing particles containing the dispersant. Therefore, in this way, when the dispersant is attached to the infrared absorbing particles, the infrared absorbing particles containing the dispersant recovered after the dispersion medium reduction step are used as infrared absorbing particles in the raw material mixed liquid preparation step.

The following is an explanation of the materials other than the infrared absorbing particles used in the raw material mixture preparation step.

(a) Resin raw materials for coating

The coating resin raw material is a coating resin that is polymerized by the polymerization step described later and arranged on at least a portion of the surface of the infrared absorbing particle. Therefore, as the coating resin raw material, various monomers that can form the desired coating resin can be selected by polymerization.

The coating resin after polymerization is not particularly limited, and one or more resins selected from, for example, thermoplastic resins, thermosetting resins, photocurable resins, etc. can be used.

In addition, as thermoplastic resins, there can be cited polyester resins, polycarbonate resins, acrylic resins, polystyrene resins, polyamide resins, vinyl chloride resins, olefin resins, fluororesins, polyvinyl acetate resins, thermoplastic polyurethane resins, acrylonitrile butadiene styrene resins, polyvinyl acetal resins, acrylonitrile-styrene copolymer resins, ethylene-vinyl acetate copolymer resins, etc.

As thermosetting resins, for example, phenolic resins, epoxy resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, thermosetting polyurethane resins, polyimide resins, polysilicone resins, etc. can be cited.

Examples of photocurable resins include resins that cure by irradiation with any of ultraviolet rays, visible rays, and near-infrared rays.

As the coating resin, it is particularly preferred to contain 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 polysilicone resin. In addition, as the above-mentioned polyurethane resin, both thermoplastic polyurethane and thermosetting polyurethane can be used.

In addition, as the coating resin, a photocurable resin can also be suitably used. As already described, the photocurable resin can include a resin that is cured by irradiation with any of ultraviolet light, visible light, and infrared light.

Among them, as the coating resin, it is preferred to use a resin to which the mini-emulsion polymerization method can be applied, for example, a polystyrene resin is more preferably contained. In addition, when the coating resin is polystyrene, styrene can be used as the coating resin raw material.

In addition, multifunctional vinyl monomers such as divinylbenzene and ethylene glycol dimethacrylate can also be added as crosslinking agents.

(b) Organic solvents

There is no particular limitation on the organic solvent. Any organic solvent can be used as long as it is non-water-soluble. Among them, low molecular weight organic solvents are preferred, for example, one or more selected from long-chain alkyl compounds such as hexadecane, alkyl methacrylates with long-chain alkyl moieties such as dodecyl methacrylate and stearyl methacrylate, higher alcohols such as cetyl alcohol, and oils such as olive oil.

As the organic solvent, a long-chain alkyl compound is particularly preferred, and hexadecane is further preferred.

(c) Emulsifier

The emulsifier, i.e., surfactant, may be any of cationic emulsifiers, anionic emulsifiers, nonionic emulsifiers, etc., without any particular limitation.

As cationic emulsifiers, alkylamine salts, quaternary ammonium salts, etc. can be cited.

As anionic emulsifiers, acid salts or ester salts can be cited.

As non-ionic emulsifiers, various esters, various ethers, various ester ethers, and alkanolamides can be cited.

As an emulsifier, for example, one or more selected from the above materials can be used.

Among them, from the perspective that infrared absorbing particles are particularly easy to form organic-inorganic hybrid infrared absorbing particles, it is preferred to use a cationic emulsifier, that is, a surfactant showing cationic properties.

In particular, when an amine compound is used as a dispersant, it is preferred to use one or more cationic dispersants selected from dodecyltrimethylammonium chloride (DTAC), cetyltrimethylammonium chloride (CTAC), etc. as an emulsifier.

In addition, when using an amine compound as a dispersant, it is sometimes difficult to form organic-inorganic hybrid infrared absorbing particles if sodium dodecyl sulfate (SDS) is used as an anionic emulsifier. When preparing the raw material mixture, the emulsifier can be added to the water added at the same time as an aqueous solution. In this case, it is preferably added as an aqueous solution adjusted to a concentration of 1 to 10 times the critical micelle concentration (CMC).

(d)Polymerization initiator

As the polymerization initiator, one or more polymerization initiators selected from various polymerization initiators such as free radical polymerization initiators and ionic polymerization initiators can be used without particular limitation.

As free radical polymerization initiators, azo compounds, dihalogens, organic peroxides, etc. can be cited. In addition, redox initiators that combine an oxidizing agent and a reducing agent, such as hydrogen peroxide and iron (II) salt, persulfate and sodium hydrogen sulfite, can also be cited.

As initiators of ionic polymerization, there are nucleophiles such as n-butyl lithium, electrophiles such as protonic acids, Lewis acids, halogen molecules, and carbon cations.

As the polymerization initiator, 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), etc. can be suitably used.

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

In the raw material mixed solution 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 can be mixed to prepare the raw material mixed solution. Therefore, the preparation step of the raw material mixed solution is not particularly limited. For example, a mixed solution containing an emulsifier can be prepared in advance as an aqueous phase. In addition, as an organic phase, a mixed solution 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 can be prepared.

In addition, the polymerization initiator can be added to the aqueous phase or the organic phase as described above, depending on the type of the polymerization initiator used.

Furthermore, by adding an organic phase to an aqueous phase and mixing them, a raw material mixed solution can be prepared.

It is preferred that the organic phase is added to the aqueous phase and then stirred sufficiently in such a manner that the coating resin can be more evenly arranged on the surface of the infrared absorbing particles. That is, the raw material mixed solution preparation step preferably includes a stirring step of stirring the obtained mixed solution in addition to a 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, the water and the polymerization initiator.

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, and for example, stirring is preferably performed in a manner such that infrared absorbing particles enclosed by the coating resin raw material are dispersed in water droplets in the aqueous phase.

The amount of polymerization initiator added is not particularly limited and can be selected arbitrarily. The amount of polymerization initiator added can be selected according to the coating resin raw material, the type of polymerization initiator, the size of the oil droplets as the fine emulsion, the ratio of the coating resin raw material to the infrared absorbing particles, etc. For example, as long as the amount of polymerization initiator added is 0.01 mol% to 1000 mol% relative to the coating resin raw material, it is easy to obtain organic-inorganic hybrid infrared absorbing particles in which the infrared absorbing particles are fully covered with the coating resin, so it is preferred. The amount of polymerization initiator added is more preferably 0.1 mol% to 200 mol% relative to the coating resin raw material, and further preferably 0.2 mol% to 100 mol%.

(4) Stirring step

In the stirring step, the raw material mixed solution obtained from the raw material mixed solution preparation step can be stirred while being cooled.

The degree of stirring in the stirring step is not particularly limited and can be selected arbitrarily. For example, it is preferred to stir in such a manner that the size of the oil droplets in water of the O/W type emulsion in which the infrared absorbing particles contained in the coating resin raw material are dispersed in the water phase, that is, the diameter becomes a fine emulsion of about 50 nm to 500 nm.

Miniemulsion is obtained by adding a substance that is basically insoluble in water, i.e., a hydrophobe, to the organic phase and applying a strong shear force. As the hydrophobe, for example, the organic solvent described in the step of preparing the raw material mixture can be cited. In addition, as a method of applying a strong shear force, for example, a method of applying ultrasonic vibration to the raw material mixture by a homogenizer can be cited.

In the stirring step, as described above, it is preferred to stir while cooling the raw material mixture. This is because by cooling the raw material mixture, the polymerization reaction can be suppressed and a mini-emulsion can be formed.

In addition, the degree to which the raw material mixture is cooled is not particularly limited, and it is preferably cooled using a cooling medium below 0°C, such as an ice bath.

(5) Polymerization step

In the polymerization step, after deoxygenation treatment is performed to reduce the amount of oxygen in the raw material mixed solution, the polymerization reaction of the coating resin raw material can be carried out.

In the polymerization step, the coating resin raw material can be polymerized, and the coating resin is arranged on at least a portion of the surface of the infrared absorbing particles.

The conditions in the polymerization step are not particularly limited, and a deoxidation treatment can be performed to reduce the amount of oxygen in the raw material mixed solution before starting the polymerization. The specific method of the deoxidation treatment is not particularly limited, and examples thereof include a method of irradiating with ultrasonic waves, a method of blowing an inert gas into the raw material mixed solution, and the like.

Furthermore, the specific conditions for carrying out the polymerization reaction can be arbitrarily selected according to the coating resin raw material added to the raw material mixture, and therefore are not particularly limited. For example, the polymerization reaction can be carried out by heating the raw material mixture or irradiating light of a specified wavelength.

According to the method for producing organic-inorganic hybrid infrared absorbing particles of the present embodiment described above, an organic material such as resin is arranged on at least a part of the surface of the infrared absorbing particles, which was difficult in the past, so that organic-inorganic hybrid infrared absorbing particles can be obtained. Therefore, even when exposed to a high-temperature chemical environment such as acid or alkali, the infrared absorbing particles can be prevented from directly contacting with chemical components such as acid or alkali, and the chemical resistance is excellent, and the reduction of infrared absorbing characteristics can be prevented.

2. Organic-inorganic hybrid infrared absorbing particles

The organic-inorganic hybrid infrared absorbing particles that can be suitably used in the infrared absorbing fiber of the present embodiment are described. The organic-inorganic hybrid infrared absorbing particles can have infrared absorbing particles and a coating resin that covers at least a portion of the surface of the infrared absorbing particles. The organic-inorganic hybrid infrared absorbing particles can be manufactured by, for example, the method for manufacturing organic-inorganic hybrid infrared absorbing particles that has been described. Therefore, the description of some of the matters that have been described is omitted.

In this way, by configuring the coating resin covering at least a portion of the surface of the infrared absorbing particles, which was difficult in the past, it is possible to suppress the infrared absorbing particles from directly contacting chemical components such as acids or alkalis even when exposed to a high-temperature acid or alkali chemical environment. Therefore, the infrared absorbing fiber of this embodiment including such organic-inorganic hybrid infrared absorbing particles has excellent chemical resistance and can suppress the reduction of infrared absorbing characteristics.

As for infrared absorbing particles, they have been described in the method for producing organic-inorganic hybrid infrared absorbing particles, so the description is omitted. For example, it is preferred to use infrared absorbing particles containing various materials containing free electrons, and it is more preferred to use infrared absorbing particles containing various inorganic materials containing free electrons.

Infrared absorbing particles including one or more selected from tungsten oxides and composite tungsten oxides having oxygen vacancies can be particularly preferably used. In this case, specifically, the infrared absorbing particles preferably contain, for example, tungsten oxide represented by the general formula _WyOz (W: tungsten, O: oxygen, 2.2≦z/y _≦ 2.999) and _at least one member represented by the general formula _MxWyOz (the element M is one _or more selected from H, He, alkali metals, alkali earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, I, 0.001≦x/y≦1, 2.0≦z/y≦3.0) or more of the composite tungsten oxides.

The coating resin has been described in the method for producing the organic-inorganic hybrid infrared absorbing particles, so its description is omitted here. For example, one or more resins selected from thermoplastic resins, thermosetting resins, photocurable resins, etc. can be used. As the coating resin, it is particularly preferred to contain 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 polysilicone resin. In addition, as the above-mentioned polyurethane resin, both thermoplastic polyurethane and thermosetting polyurethane can be used.

In addition, as the coating resin, a photocurable resin can also be suitably used. As described above, the photocurable resin can be a resin that is cured by irradiation with any of ultraviolet rays, visible rays, and infrared rays.

Among them, as the coating resin, it is preferred to use a resin to which the mini-emulsion polymerization method can be applied, for example, a polystyrene resin is more preferred.

The organic-inorganic hybrid infrared absorbing particles described above are provided with a coating resin as an organic material on at least a portion of the surface of the infrared absorbing particles, which was difficult in the past. Therefore, even when exposed to a high-temperature acid or alkali chemical environment, the infrared absorbing particles can be prevented from directly contacting chemical components such as acid or alkali, so the chemical resistance is excellent and the reduction of the infrared absorbing characteristics can be suppressed. In addition, the infrared absorbing fiber using the organic-inorganic hybrid infrared absorbing particles can also have chemical resistance.

The infrared absorbing fiber of this embodiment can include fibers other than the organic-inorganic hybrid infrared absorbing particles described so far.

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 including the dispersion in one or more parts selected from the inside and the surface of the fiber. The fiber, etc., will be described below.

3. Fiber

The fiber of the infrared absorbing fiber of this embodiment can be selected in various ways depending on the application.

The fiber of the infrared absorbing fiber of the present embodiment can include, for example, one or more selected from synthetic fibers, semi-synthetic fibers, natural fibers, regenerated fibers, and inorganic fibers. Specifically, as the fiber, for example, one or more selected from the fiber group consisting of synthetic fibers, semi-synthetic fibers, natural fibers, regenerated fibers, and inorganic fibers, one or more selected from the mixed yarns formed by blending, combining, and blending of one or more selected from the above fiber groups, etc., are not a problem. Considering the use of a simple method to contain organic-inorganic hybrid infrared absorbing particles in the fiber and the thermal insulation sustainability, the fiber preferably includes synthetic fibers, and more preferably synthetic fibers.

When the infrared absorbing fiber of the present embodiment includes synthetic fibers as fibers, the specific type of the synthetic fibers is not particularly limited. For example, the synthetic fibers can be suitably selected from one or more of polyurethane fibers, polyamide fibers, acrylic fibers, polyester fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, polyether ester fibers, etc.

As polyamide-based fibers, for example, one or more selected from nylon, nylon 6, nylon 66, nylon 11, nylon 610, nylon 612, aromatic nylon, aromatic polyamide, etc. can be cited.

As acrylic fibers, for example, one or more selected from polyacrylonitrile, acrylonitrile-vinyl chloride copolymer, modified polyacrylonitrile, etc. can be cited.

As polyester-based fibers, for example, one or more selected from polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, etc. can be cited.

As polyolefin fibers, for example, one or more selected from polyethylene, polypropylene, polystyrene, etc. can be cited.

Examples of polyvinyl alcohol-based fibers include vinyl and the like.

Examples of polyvinylidene chloride-based fibers include polyvinylidene chloride fibers.

Examples of polyvinyl chloride-based fibers include polyvinyl chloride.

As polyetherester-based fibers, one or more selected from REXE, SUCCESS, etc. can be cited.

When the infrared absorbing fiber of the present embodiment includes semi-synthetic fiber as the fiber, the semi-synthetic fiber preferably includes one or more selected from cellulose-based fiber, protein-based fiber, chlorinated rubber, hydrochloric acid rubber, etc.

As cellulose-based fibers, for example, one or more selected from acetate, triacetate, oxyacetate, etc. can be cited.

As protein fibers, for example, Promix can be cited.

When the infrared absorbing fiber of the present embodiment includes natural fibers as fibers, the natural fibers preferably include, for example, one or more selected from plant fibers, animal fibers, mineral fibers, etc.

As plant fibers, for example, one or more selected from cotton, kapok, linen, hemp, jute, abaca, ramie, ramie, ramie, coconut, juncea, wheat, etc. can be cited.

As animal fibers, for example, one or more selected from wool, goat hair, angora goat hair, cashmere, alpaca, mohair, camel hair, lanolin, etc., silk, down, feathers, etc. can be cited.

As mineral fibers, for example, one or more selected from asbestos, asbestos, etc. can be cited.

When the infrared absorbing fiber of the present embodiment includes regenerated fiber as the fiber, the regenerated fiber preferably includes one or more selected from cellulose-based fiber, protein-based fiber, alginate fiber, rubber fiber, chitin fiber, mannan fiber, etc.

As cellulose-based fibers, for example, one or more selected from rayon, viscose rayon, capro, polynosic, capro, etc. can be cited.

As the protein-based fiber, for example, one or more selected from casein fiber, peanut protein fiber, corn protein fiber, soybean protein fiber, regenerated silk, etc. can be cited.

When the infrared absorbing fiber of the present embodiment includes inorganic fibers as fibers, the inorganic fibers preferably include one or more selected from metal fibers, carbon fibers, silicate fibers, etc., for example.

As the metal fiber, for example, one or more selected from metal fibers, gold wires, silver wires, heat-resistant alloy fibers, etc. can be cited.

As silicate fibers, for example, one or more selected from glass fibers, slag fibers, rock fibers, etc. can be cited.

The cross-sectional shape of the infrared absorbing fiber of the present embodiment is not particularly limited, and for example, one or more of the shapes selected from circular, triangular, hollow, flat, Y-shaped, star-shaped, core-sheath, etc. can be cited. In addition, the infrared absorbing fiber of the present embodiment can also contain fibers of different cross-sectional shapes at the same time.

The configuration of the organic-inorganic hybrid infrared absorbing particles in one or more parts selected from the inside and the surface of the fiber can adopt various forms according to 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 can be contained in the core of the fiber or in the sheath of the fiber. In addition, the shape of the fiber possessed by the infrared absorbing fiber of this embodiment can be a filament (long fiber) or a chemical staple fiber (short fiber).

4. Additives

The infrared absorbing fiber of this embodiment can contain antioxidants, flame retardants, deodorants, insect repellents, antibacterial agents, ultraviolet absorbers, etc. according to the purpose within the range that does not damage the performance of the contained fiber.

In addition, the infrared absorbing fiber of the present embodiment may further contain particles capable of radiating far infrared rays in addition to the infrared absorbing material. The particles capable of radiating far infrared rays may be arranged in one or more parts selected from, for example, the inside and the surface of the fiber. As the particles capable of radiating far infrared rays, 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 _can be suitably used.

The infrared absorbing fiber of this embodiment has an infrared absorbing material, and the organic-inorganic hybrid infrared absorbing particles as a near-infrared absorbing material have the property of absorbing solar energy with a wavelength of 0.3μm to 3μm, and in particular selectively absorbs the near-infrared region with a wavelength of 0.9μm to 2.2μm, converts it into heat, or re-dissipates it.

On the other hand, the particles radiating far infrared rays receive the energy absorbed by the organic-inorganic hybrid infrared absorbing particles as near infrared absorbing materials, and have the ability to convert the energy into heat energy of mid- and far infrared wavelengths and radiate it. For example, _ZrO2 particles convert the energy into heat energy of wavelengths of 2 μm to 20 μm, and radiate it. Therefore, the particles having the ability to radiate far infrared rays and the organic-inorganic hybrid infrared absorbing particles coexist in the fiber and on the surface, so that, for example, the solar energy absorbed by the organic-inorganic hybrid infrared absorbing particles is efficiently consumed in the fiber and on the surface, and more effective heat preservation is performed.

As described above, the infrared absorbing fiber of this embodiment can be configured with organic-inorganic hybrid infrared absorbing particles in one or more parts selected from the inside and the surface of the fiber. That is, the organic-inorganic hybrid infrared absorbing particles can be configured in both the inside and the surface of the fiber, or in either the inside or the surface of the fiber.

Furthermore, as already described, the organic-inorganic hybrid infrared absorbing particles have excellent chemical resistance, so the infrared absorbing fiber of the present embodiment containing the organic-inorganic hybrid infrared absorbing particles can also have excellent chemical resistance.

[Manufacturing method of infrared absorbing fiber]

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

For example, the infrared absorbing fiber of this embodiment can be manufactured by the following manufacturing methods (a) to (d).

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

(b) A method of pre-producing a masterbatch containing organic-inorganic hybrid infrared absorbing particles at a high concentration in a part of the raw polymer, and then diluting it to a predetermined concentration during spinning before spinning.

(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 the dispersion, and the organic-inorganic hybrid infrared absorbing particles are dispersed in the raw material polymer before spinning.

(d) A method in which organic-inorganic hybrid infrared absorbing particles are attached to the surface of pre-spun fibers using an adhesive or the like.

Here, the above-mentioned production methods (a) to (d) for making the infrared absorbing fiber of the present embodiment contain organic-inorganic hybrid infrared absorbing particles are described with specific examples.

(a) Method:

For example, the case where polyester fiber is used as the fiber will be explained.

An organic-inorganic hybrid infrared absorbing particle dispersion is added to polyethylene terephthalate resin particles as a thermoplastic resin, and after uniformly mixing with a stirrer, the solvent is removed. The mixture from which the solvent has been removed is melt-kneaded with a double-screw extruder to obtain a masterbatch containing organic-inorganic hybrid infrared absorbing particles. The masterbatch containing organic-inorganic hybrid infrared absorbing particles is melt-mixed at a temperature near the melting temperature of the resin and spun according to various known methods, for example.

At this time, in order to improve the dispersibility of the organic-inorganic hybrid infrared absorbing particles in the polyethylene terephthalate resin, a dispersant can be added. The dispersant is not limited as long as it can disperse the organic-inorganic hybrid infrared absorbing particles in the polyethylene terephthalate resin or the fiber obtained by spinning the masterbatch containing the resin. For example, the dispersant used for the polyethylene terephthalate resin is not particularly limited, for example, it is preferably a polymer dispersant, and more preferably a dispersant having any main chain selected from polyester, polyether, polyacrylic acid, polyurethane, polyamine, polystyrene, and aliphatic series, or a main chain formed by copolymerization of two or more unit structures selected from polyester, polyether, polyacrylic acid, polyurethane, polyamine, polystyrene, and aliphatic series.

In addition, the dispersant preferably has one or more selected from an amine-containing group, a hydroxyl group, a carboxyl group, a carboxyl group, a sulfonic group, a phosphoric acid group or an epoxy group as a functional group. In particular, a polyacrylic acid system having an amine-containing group as a functional group is preferred. A dispersant having any of the above functional groups can be adsorbed on the surface of the organic-inorganic hybrid infrared absorbing particles to more reliably prevent the aggregation of the organic-inorganic hybrid infrared absorbing particles. Therefore, the organic-inorganic hybrid infrared absorbing particles can be dispersed more uniformly, so it can be used appropriately.

Examples of such dispersants include SOLSPERSE (registered trademark) (hereinafter the same) 9000, 12000, 17000, 20000, 21000, 24000, 26000, 27000, 28000, 32000, 35100, 54000, SOLTHIX250, EFKA manufactured by Japan Lubrizol Co., Ltd. EFKA (registered trademark) (hereinafter the same) manufactured by Additives Co., Ltd. 4008, EFKA4009, EFKA4010, EFKA4015, EFKA4046, EFKA4047, EFKA4060, EFKA4080, EFKA7462, EFKA4020, EFKA4050, EFKA4055, EFKA4585, EFKA4400, EFKA4401, EFKA4402, EFKA4403, EFKA4300, EFKA4320, EFKA4330, EFKA4340, EFKA6220, EFKA6225, EFKA6700, EFKA6780, EFKA6782, EFKA8503, Ajinomoto Fine Techno Co., Ltd. ajisper (registered trademark) (hereinafter the same) PB821, ajisper PB822, ajisper PB824, ajisper PB881, FAMEXL-12, BYKJapan Co., Ltd. DisperBYK (registered trademark) (hereinafter the same) 101, DisperBYK106, DisperBYK108, DisperBYK116, DisperBYK130, DisperBYK140, DisperBYK142, DisperBYK145, DisperBYK161, DisperBYK162, DisperBYK163, DisperBYK164, DisperBYK166, DisperBYK167, Di sperBYK168、DisperBYK171、DisperBYK180、DisperBYK182、DisperBYK2000、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) manufactured by Kusumoto Chemicals Co., Ltd. 1831、DISPARLON 1850, DISPARLON 1860, 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, TERPLUS (registered trademark) MD1000, D 1180, D 1130 manufactured by Otsuka Chemical Co., Ltd.

(b) Method:

A masterbatch containing organic-inorganic hybrid infrared absorbing particles is prepared by effectively using the same method as (a), and the masterbatch and a masterbatch formed by polyethylene terephthalate without adding organic-inorganic hybrid infrared absorbing particles are melt-mixed at a desired mixing ratio near the melting temperature of the resin, and spinning is performed according to a known method.

(c) Method:

For example, the case where urethane fiber is used as the fiber will be explained.

A high molecular weight diol containing organic-inorganic hybrid infrared absorbing particles is reacted with an organic diisocyanate in a double-screw extruder to synthesize an isocyanate-terminated prepolymer, and then a chain extender is reacted therein to produce a polyurethane solution (raw polymer). The polyurethane solution is spun according to various known methods.

(d) Method:

For example, the case where organic-inorganic hybrid infrared absorbing particles are attached to the surface of natural fibers will be explained.

First, prepare a treatment solution that contains mixed organic and inorganic infrared absorbing particles, one or more adhesive resins selected from acrylic, epoxy, amine, and polyester, and a solvent such as water.

Next, the natural fiber is immersed in the prepared treatment liquid, or the prepared treatment liquid is impregnated into the natural fiber by filling, printing or spraying, and then dried. In this way, the organic-inorganic hybrid infrared absorbing particles can be attached to the natural fiber. In addition to the above-mentioned natural fiber, the method (d) can be applied to semi-synthetic fiber, regenerated fiber, inorganic fiber, or any of their blends, filaments, and blends.

In addition, when implementing methods (a) to (d), the dispersion method of the organic-inorganic hybrid infrared absorbing particles in the solvent (dispersion medium) is not particularly limited, and any method can be used as long as it can make the organic-inorganic hybrid infrared absorbing particles uniformly dispersed in the liquid, that is, the solvent. For example, methods that can be suitable for applying medium stirring mills, ball mills, sand mills, ultrasonic dispersion, etc.

In addition, the solvent of the organic-inorganic hybrid infrared absorbing particles is not particularly limited and can be selected according to the mixed fibers. For example, one or more of various general organic solvents such as alcohols, ethers, esters, ketones, aromatic compounds, and water can be used.

Furthermore, when the organic-inorganic hybrid infrared absorbing particles are attached to the fibers and the polymers as raw materials and mixed, the dispersion of the organic-inorganic hybrid infrared absorbing particles can be directly mixed with the fibers and the polymers as raw materials. In addition, as needed, acid and alkali can be added to the dispersion of the organic-inorganic hybrid infrared absorbing particles to adjust the pH, and various surfactants, coupling agents, etc. can also be added to further improve the dispersion stability of the organic-inorganic hybrid infrared absorbing particles.

The content of the organic-inorganic hybrid infrared absorbing particles contained in the infrared absorbing fiber of the present embodiment is not particularly limited. For example, the content of the organic-inorganic hybrid infrared absorbing particles in the infrared absorbing fiber of the present embodiment is preferably 0.001 mass % to 80 mass %. Furthermore, considering the weight of the infrared absorbing fiber after the addition of the organic-inorganic hybrid infrared absorbing particles and the cost of raw materials, the content of the organic-inorganic hybrid infrared absorbing particles in the infrared absorbing fiber is more preferably 0.005 mass % to 50 mass %.

When the content ratio of the organic-inorganic hybrid infrared absorbing particles in the infrared absorbing fiber is 0.001 mass % or more, for example, even if the fabric using the infrared absorbing fiber becomes thinner, a sufficient infrared absorbing effect can be obtained.

In addition, if the content ratio of the organic-inorganic hybrid infrared absorbing particles in the infrared absorbing fiber is 80% by mass or less, it is preferred because the reduction in spinnability caused by filter mesh clogging and wire breakage during the spinning step can be avoided. In particular, if it is 50% by mass or less, it is further preferred. In addition, since the addition amount of the organic-inorganic hybrid infrared absorbing particles is small, it basically does not damage the physical properties of the fiber, which is preferred.

As described above, according to the infrared absorbing fiber involved in this embodiment, by configuring infrared absorbing particles inside and on the surface of the fiber, it is possible to provide a fiber that efficiently absorbs infrared rays from sunlight and the like and has excellent heat preservation. In addition, the infrared absorbing fiber involved in this embodiment has high chemical resistance, so even if exposed to a chemical environment such as high-temperature acid or alkali, the infrared absorbing property does not decrease. As a result, the infrared absorbing fiber involved in this embodiment can be used for various purposes such as fiber products that require heat preservation, such as winter clothing, sports clothing, stockings, curtains, and other industrial fiber products.

[Fiber products]

The fiber product of this embodiment is processed from the infrared absorbing fiber already described, and can include the infrared absorbing fiber already described. In addition, the fiber product of this embodiment can also be formed from the infrared absorbing fiber already described.

The fiber product of this embodiment including the infrared absorbing fiber described above has excellent properties of a visible light absorption rate of less than 20% and a sunlight absorption rate of more than 47%. The so-called visible light absorption rate of less than 20% and a sunlight absorption rate of more than 47% means that the fiber product is light in color and has an excellent infrared absorption effect.

The fiber product of the present embodiment including the infrared absorbing fiber of the present embodiment has excellent chemical resistance. For example, even when immersed in a 0.01 mol/L sodium hydroxide aqueous solution maintained at 80°C for 30 minutes, the above-mentioned solar absorption rate is maintained at more than 47%. That is, the fiber product of the present embodiment can have chemical resistance.

[Implementation example]

Hereinafter, the present invention will be described in detail with reference to the embodiments. However, the present invention is not limited to the following embodiments.

In addition, the optical properties of the fiber products obtained from the embodiments 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.

The measurement of the crystallite diameter of the infrared absorbing particles uses dry powder of the infrared absorbing particles obtained by removing the solvent from the dispersion of the infrared absorbing particles. The X-ray diffraction pattern of the infrared absorbing particles is measured using a powder X-ray diffraction device (X'Pert-PRO/MPD manufactured by Spectris PANalytical Co., Ltd.) using the powder X-ray diffraction method (θ-2θ method). The crystal structure contained in the infrared absorbing particles is specified from the obtained X-ray diffraction pattern, and the crystallite diameter is further calculated using the Rydberg method.

[Implementation Example 1]

Infrared absorbing fibers and fiber products were produced and evaluated through the following steps.

1. Manufacture of organic-inorganic hybrid infrared absorbing particles

According to the following steps, the organic-inorganic hybrid infrared absorbing particles used in infrared absorbing fibers are manufactured.

(Dispersion preparation steps)

In the dispersion preparation step, a dispersion containing infrared absorbing particles, a dispersant and a dispersion medium is prepared.

As infrared absorbing particles, composite tungsten oxide powder (YM-01 manufactured by Sumitomo Metal Mining Co., Ltd.) containing hexagonal cesium tungsten bronze (Cs _0.33 WO _z , 2.0≦z≦3.0) having a mass ratio of cesium (Cs) to tungsten (W) of Cs/W=0.33 was prepared.

As a dispersant, a polymer dispersant of a copolymer of styrene and 2-(dimethylamino)ethyl methacrylate was prepared.

In addition, as a dispersion medium, toluene was prepared.

Then, a mixed solution of 10 mass % of infrared absorbing particles, 3 mass % of dispersant and 87 mass % of dispersion medium was placed in a paint shaker containing 0.3 mmφ ZrO ₂ beads, and the mixture was crushed and dispersed for 10 hours to obtain a dispersion of Cs _0.33 WO _z particles according to Example 1.

(Dispersing medium reduction step)

From the dispersion of Cs _0.33 WO _z particles obtained in the dispersion preparation step, toluene as a dispersion medium is removed using an evaporator to recover infrared absorbing particles. The recovered infrared absorbing particles become dry powder of Cs _0.33 WO _z particles containing a polymer dispersant.

The crystallite diameter of the recovered infrared absorbing particles, namely Cs _0.33 WO _z particles, was measured and found to be 16 nm.

In addition, the crystallite diameter was measured and calculated by the method already described.

(Raw material mixture preparation steps)

0.05 g of infrared absorbing particles obtained from the dispersion medium reduction step, 1.0 g of styrene as a coating resin raw material, and 0.065 g of hexadecane as an organic solvent were mixed to form an organic phase.

In addition, separately from the above-mentioned organic phase, dodecyltrimethylammonium chloride as an emulsifier, 0.013g of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V-50) as a polymerization initiator, and water were mixed to form 10g of an aqueous phase. In addition, when forming the aqueous phase, dodecyltrimethylammonium chloride as an emulsifier was added to the water in a concentration 1.5 times the critical micelle concentration. In addition, the polymerization initiator was added in a manner to become 0.5mol% relative to the styrene added to the organic phase.

Then, the raw material mixture is prepared by adding the organic phase to the aqueous phase.

(Stirring step)

The raw material mixture prepared in the raw material mixture preparation step was irradiated with high-output ultrasound for 15 minutes while being cooled in an ice bath to obtain a fine emulsion.

(Aggregation step)

After the stirring step, the raw material mixture was deoxygenated by bubbling nitrogen for 15 minutes in an ice bath.

Then, a heat treatment was carried out at 70°C for 6 hours in a nitrogen atmosphere to polymerize styrene and obtain an organic-inorganic hybrid infrared absorbing particle dispersion.

The obtained dispersion containing organic-inorganic hybrid infrared absorbing particles was diluted and transferred to a microgrid for TEM observation, and TEM observation of the transferred material was performed. The TEM image is shown in FIG2. From the TEM image, it was confirmed that the particles 21 containing the composite tungsten oxide, which appeared black, as infrared absorbing particles, were encapsulated in the film 22 of polystyrene, which appeared gray, as a coating resin, to form organic-inorganic hybrid infrared absorbing particles 23. In addition, the organic-inorganic hybrid infrared absorbing particles were visually confirmed to be light-colored. In addition, the microgrids 24 also appeared in FIG2, but they did not constitute the organic-inorganic hybrid infrared absorbing particles.

2. Manufacturing of infrared absorbing fibers

The obtained organic-inorganic hybrid infrared absorbing particle dispersion and a water-soluble acrylic adhesive resin are mixed to prepare a treatment solution. Next, the polyester fiber is immersed in the prepared treatment solution and dried to produce the infrared absorbing fiber involved in Example 1 with organic-inorganic hybrid infrared absorbing particles attached thereto.

3. Manufacturing of fiber products

The obtained infrared absorbing fiber is cut to produce polyester short fibers, and the fibers are used to produce short fiber yarns. And, using the short fiber yarns, the woven product involved in Example 1 is obtained. In addition, the solar absorption rate of the woven product sample is adjusted to be about 50%. The following comparative examples are also adjusted in the same way.

4. Evaluation of fiber products

The optical properties of the fiber product involved in Example 1 were measured by the above method. The visible light absorptivity and sunlight absorptivity were calculated by visible light absorptivity (%) = 100% - visible light transmittance (%) - visible light reflectance (%) and sunlight absorptivity (%) = 100% - sunlight transmittance (%) - sunlight reflectance (%). The calculated visible light absorptivity and sunlight absorptivity were 18% and 51%, respectively. In addition, the color tone of the woven product was visually confirmed, and the result was a light color.

5. Evaluation of alkali resistance

The fiber product involved in Example 1 was immersed in a 0.01 mol/L sodium hydroxide aqueous solution maintained at 80°C for 30 minutes to conduct an alkali resistance test. Then, the optical properties were measured again.

The visible light absorption rate and sunlight absorption rate after the alkali resistance test were 17% and 49% respectively. When comparing before and after the alkali resistance test, the difference in visible light absorption rate and sunlight absorption rate was 1% and 2% respectively. The evaluation results are shown in Table 1.

That is, it can be confirmed that the light absorption rate of the infrared absorbing fiber before and after the alkali resistance test does not change significantly. Therefore, it can be confirmed that the infrared absorbing fiber and fiber products obtained by this embodiment have chemical resistance, especially alkali resistance.

[Comparative example 1]

In the dispersion preparation step, a dispersion containing infrared absorbing particles and a dispersion medium is prepared.

As infrared absorbing particles, composite tungsten oxide powder (YM-01 manufactured by Sumitomo Metal Mining Co., Ltd.) containing hexagonal cesium tungsten bronze (Cs _0.33 WO _z , 2.0≦z≦3.0) having a mass ratio of cesium (Cs) to tungsten (W) of Cs/W=0.33 was prepared.

Prepare pure water as a dispersion medium.

Then, a mixed solution of 10 mass % of infrared absorbing particles and 90 mass % of a dispersion medium was placed in a paint shaker containing 0.3 mmφ ZrO ₂ beads, and the mixture was crushed and dispersed for 10 hours to obtain a dispersion of Cs _0.33 WO _z particles according to Comparative Example 1.

Pure water as a dispersion medium is removed from the dispersion of Cs _0.33 WO _z particles obtained in the dispersion preparation step using an evaporator to recover infrared absorbing particles. The recovered infrared absorbing particles become dry powder of Cs _0.33 WO _z particles.

The crystallite diameter of the recovered infrared absorbing particles, namely Cs _0.33 WO _z particles, was measured and found to be 16 nm.

In addition, the crystallite diameter was measured and calculated by the method already described.

The same operation as in Example 1 was performed except that the dispersion of Cs _0.33 WO _z particles involved in Comparative Example 1 prepared in the above-mentioned dispersion preparation step was used instead of the organic-inorganic hybrid infrared absorbing particle dispersion of Example 1, thereby obtaining infrared absorbing fibers and fiber products involved in Comparative Example 1. The obtained fiber products were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

[Table 1]

From the evaluation results of the optical properties of the fiber products before and after the alkali resistance test shown in Table 1 above, it can be confirmed that in the fiber product using the organic-inorganic hybrid infrared absorbing particles of Example 1 in which a coating resin is arranged on at least a portion of the surface of the infrared absorbing particles, the light absorption properties do not change significantly before and after the test.

Therefore, it can be confirmed that the infrared absorbing fiber using the organic-inorganic hybrid infrared absorbing particles of Example 1 and the fiber product containing the infrared absorbing fiber have excellent alkali resistance, that is, chemical resistance, and excellent infrared absorption characteristics. Only the alkali resistance test was performed here, but at least a part of the surface of the infrared absorbing particles of these organic-inorganic hybrid infrared absorbing particles is provided with a coating resin, so they also have acid resistance characteristics.

On the other hand, it was confirmed that the infrared absorption property of the fiber product using the infrared absorbing particles of Comparative Example 1 disappeared after the alkali resistance test, indicating that the fiber product did not have alkali resistance.

In the above, the infrared absorbing fiber and fiber products are described using the embodiments and examples, but the present invention is not limited to the above embodiments and examples. Various modifications and changes can be made within the scope of the main purpose of the present invention described in the claims.

21: Particles 22: Coating 23: Organic-inorganic hybrid infrared absorbing particles 24: Microgrid

Claims (10)

A fiber product, comprising an infrared absorbing fiber, the infrared absorbing fiber comprising: fiber, and organic-inorganic hybrid infrared absorbing particles, the organic-inorganic hybrid infrared absorbing particles having infrared absorbing particles and a covering resin covering at least a portion of the surface of the infrared absorbing particles, the organic-inorganic hybrid infrared absorbing particles being arranged in one or more portions selected from the interior and the surface of the fiber, the fiber product having a solar absorption rate of 47% or more after being immersed in a 0.01 mol/L sodium hydroxide aqueous solution maintained at 80°C for 30 minutes. A fiber product as claimed in claim 1, wherein the coating resin contains one or more selected from polyester resins, polycarbonate resins, acrylic resins, polyamide resins, vinyl chloride resins, olefin resins, fluororesins, polyvinyl acetate resins, polyurethane resins, acrylonitrile butadiene styrene resins, polyvinyl acetal resins, acrylonitrile-styrene copolymer resins, ethylene-vinyl acetate copolymer resins, phenolic resins, epoxy resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, polyimide resins, and polysilicone resins. A fiber product as claimed in claim 2, 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. The fiber product of any one of claims 1 to 3, wherein the infrared absorbing particles contain tungsten oxides selected from _the group consisting of _WyOz (W: tungsten, O: oxygen, 2.2≦ _z /y≦2.999) _{and MxWyOz} (the element M is one or more selected from H, He, alkali metals, alkali earth metals, rare earth elements, 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, 0.001≦x/y≦1, 2.0≦z/y≦3.0) of the composite tungsten oxide. The fiber product according to any one of claims 1 to 3, wherein the fiber comprises one or more selected from synthetic fibers, semi-synthetic fibers, natural fibers, regenerated fibers, and inorganic fibers. A fiber product as claimed in claim 5, wherein the synthetic fiber comprises at least one selected from polyurethane fibers, polyamide fibers, acrylic fibers, polyester fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, and polyetherester fibers. The fiber product of claim 5, wherein the semi-synthetic fiber comprises at least one selected from the group consisting of cellulose-based fibers, protein-based fibers, chlorinated rubber, and hydrochloric acid rubber. The fiber product of claim 5, wherein the natural fiber comprises at least one selected from plant fiber, animal fiber, and mineral fiber. The fiber product of claim 5, wherein the regenerated fiber comprises one or more selected from cellulose-based fibers, protein-based fibers, alginate fibers, rubber fibers, chitin fibers, and mannan fibers. The fiber product of claim 5, wherein the inorganic fiber comprises at least one selected from metal fiber, carbon fiber, and silicate fiber.