JP2017122042A - Infrared-shielding transparent substrate and infrared-shielding optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an infrared-shielding transparent substrate using a boride particle which can be easily pulverized.SOLUTION: The present invention provides an infrared-shielding transparent substrate that has a coating layer on at least one side of a transparent substrate, where the coating layer has an infrared-shielding particle and a binder. The infrared-shielding particle is a boride particle represented by general formula XB(where, X is one or more metal element selected from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sr, and Ca, and m is a number showing an amount of boron in the composition formula) and has an amount of carbon of 0.2 mass% or less when measured by a combustion-infrared absorption method.SELECTED DRAWING: None

Description

  The present invention relates to an infrared shielding transparent base material and an infrared shielding optical member.

  Conventionally, rare earth element boride particles such as La are synthesized by a solid phase reaction method and then pulverized by a dry pulverization method, and in particular, a method of pulverizing particles by colliding with a high-speed air stream such as a jet mill. Is common. Among rare earth element boride particles, for example, lanthanum hexaboride is obtained by heating lanthanum oxide and boron oxide to a high temperature in the presence of carbon, and then pulverized by a dry pulverizer. A method for finely pulverizing powder using a jet mill is disclosed in Patent Document 1, for example.

  These boride particles have been conventionally used in thick film resistance pastes and the like, and when fine particles are used, they can be used as an optical material for solar radiation shielding. That is, a film in which boride particles are dispersed is suitable as a solar radiation shielding material to be applied to a window of a house or a car because it can efficiently block near infrared rays that transmit visible light and act as heat energy. It is known (see, for example, Patent Documents 2 and 3).

  However, since borides of rare earth elements such as La are hard, it is difficult to pulverize them into fine particles by a dry pulverization method using a jet mill or the like, and only relatively large particles of about 1 μm to 3 μm can be obtained. There was a problem. In addition, boride particles obtained by the dry pulverization method are difficult to suppress reaggregation.

  In subsequent studies, it was found that the average dispersed particle diameter of boride particles can be reduced to 200 nm or less by treating with a medium stirring mill (see, for example, Patent Document 4). Thereby, boride particles having an average dispersed particle diameter of about 200 nm can be obtained economically. If boride particles having an average dispersed particle size of 200 nm or less are used, geometrical scattering or Mie scattering that occurs when the particle size is larger than 200 nm can be reduced. For this reason, the phenomenon which scatters the light of the visible light region of 400 nm-780 nm, and becomes like a frosted glass can be prevented, and the optical member which attached importance to transparency came to be obtained.

  However, as an infrared shielding particle, the infrared shielding optical member in which the boride particles are dispersed is a phenomenon that turns blue-white when irradiated with strong light such as sunlight or a spotlight (hereinafter referred to as “blue”). May be described as “haze”). When such blue haze is generated, there is a problem that the beauty of the infrared shielding optical member may be impaired.

  It is known that when the average dispersed particle size of boride particles is 200 nm or less, geometrical scattering or Mie scattering is reduced, and most of the scattering follows Rayleigh scattering whose scattering coefficient is defined by the following formula (1). .

S = [16π ⁵ r ⁶ / 3λ ⁴ ] · [(m ² −1) / (m ² +2)] ² · [m] (1)
[In the above formula (1), S is the scattering coefficient, λ is the wavelength, r is the particle diameter, m = n ₁ / n ₀ , n ₀ is the refractive index of the substrate, and n ₁ is the refractive index of the dispersed material. Is]
The Rayleigh scattering is light scattering by particles having a size smaller than the wavelength of light. From the above formula (1), it is understood that Rayleigh scattering is inversely proportional to the fourth power of the wavelength (λ), and therefore, a large amount of blue light having a short wavelength is scattered and discolored to bluish white.

  In the Rayleigh scattering region, the scattered light is proportional to the sixth power of the particle diameter (r) from the above formula (1). Therefore, by reducing the particle diameter, the Rayleigh scattering is reduced and the generation of blue haze is reduced. Can be suppressed. Subsequent studies have shown that blue haze can be improved by reducing the average dispersed particle size to 85 nm or less.

Japanese Patent Laid-Open No. 2001-314776 JP 2000-096034 A JP-A-11-181336 JP 2004-237250 A

V. Domnich et al., J. Am. Ceram. Soc., (2011) vol.94, Issue 11, pp.3605-3628 X.H.Zhao et al., App. Mech. Mater., (2011) vol.55-57, pp.1436-1440

  However, if the conventionally used boride particles are pulverized until the average dispersed particle diameter is 85 nm or less by the pulverization method using a medium stirring mill disclosed in Patent Document 4, the viscosity of the slurry becomes In some cases, the pulverization was difficult due to the increase in the height.

  Therefore, in order to continue the pulverization process to further reduce the average dispersed particle size and suppress blue haze, it is necessary to extremely reduce the concentration of boride particles in the slurry to lower the viscosity, resulting in poor pulverization efficiency and uneconomical efficiency. There was a problem that it was.

  Then, in view of the problem of the above-described conventional technology, an object of one aspect of the present invention is to provide an infrared shielding transparent base material using boride particles that can be easily pulverized.

In order to solve the above problems, according to one aspect of the present invention,
Having a coating layer on at least one surface of the transparent substrate;
The coating layer includes infrared shielding particles and a binder,
The infrared shielding particles have the general formula XB _m (where X is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sr, and Ca. Infrared which is a boride particle represented by one or more selected metal elements, m is a number indicating the amount of boron in the general formula), and the carbon content is 0.2% by mass or less as measured by a combustion-infrared absorption method A shielding transparent substrate is provided.

  According to one embodiment of the present invention, an infrared shielding transparent base material using boride particles that can be easily pulverized can be provided.

Explanatory drawing (the 1) of the measurement principle of diffuse transmission profiles, such as an infrared shielding transparent base material which concerns on embodiment of this invention. Explanatory drawing (the 2) of the measurement principle of diffuse transmission profiles, such as an infrared shielding transparent base material concerning embodiment of this invention.

DESCRIPTION OF EMBODIMENTS 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 the following embodiments are not departed from the scope of the present invention. Various modifications and substitutions can be made.
(Infrared shielding transparent base material, infrared shielding optical member)
In the present embodiment, first, a configuration example of the infrared shielding transparent base material will be described.

The infrared shielding transparent substrate of the present embodiment has a coating layer on at least one surface of the transparent substrate, and the coating layer can contain infrared shielding particles and a binder.
The infrared shielding particles have the general formula XB _m (where X is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sr, Ca 1 or more types of metal elements selected from the above, m is a number representing the boron content in the general formula), and boride particles having a carbon content of 0.2% by mass or less as measured by a combustion-infrared absorption method. Can be used.

  As described above, the infrared shielding transparent substrate of the present embodiment can have a transparent substrate and a coating layer disposed on at least one surface of the transparent substrate. The coating layer can include infrared shielding particles and a binder.

First, the infrared shielding particles and the production method thereof will be described.
(1) Infrared shielding particles and production method thereof As the infrared shielding particles, as described above, the general formula XB _m (where X is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, One or more metal elements selected from Dy, Ho, Er, Tm, Yb, Lu, Sr, and Ca, m is a number indicating the amount of boron in the general formula), and measured by a combustion-infrared absorption method Boride particles having a carbon content of 0.2% by mass or less can be used.

  The inventors of the present invention have intensively studied boride particles that can be easily pulverized, that is, pulverized into fine particles. The inventors have found that boride particles that can be easily finely pulverized can be obtained by setting the carbon content (carbon concentration) of the boride particles to a predetermined value or less, thereby completing the present invention.

Boride particles of this embodiment may be particles of boride of the general formula XB _m as described above.

In the boride particles of the present embodiment represented by the above general formula XBm, _m , which is the elemental ratio (molar ratio) (B / X) of boron (B) to metal element (X), is particularly limited. Although it is not a thing, it is preferable that it is 3.0-20.0.

The boride constituting the boride particles represented by the general formula XB _m, e.g. _{XB 4, XB 6, XB 12,} and the like. However, from the viewpoint of selectively and efficiently reducing the light transmittance in the near-infrared region near the wavelength of 1000 nm, the boride particles of the present embodiment are preferably mainly composed of XB ₄ or XB _6. , XB ₁₂ may be partially included.

For this reason, in the general formula XBm, _m , which is an element ratio (B / X) of boron (B) to metal element (X), is more preferably 4.0 or more and 6.2 or less.

The above (B / X) if there is a 4.0 or higher, XB and, it is possible to suppress the formation of such XB _2, the reason is not clear, it is possible to improve the solar radiation shielding properties. Moreover, when (B / X) is 6.2 or less, the content ratio of hexaboride having particularly excellent solar radiation shielding properties can be increased, and the solar radiation shielding properties are improved, which is preferable.

In particular, the boride particles of the present embodiment are preferably mainly composed of XB ₆ because of the high absorption ability of near infrared rays in borides.

Therefore, in the boride particles of the present embodiment represented by the general formula XBm, _m , which is the element ratio (B / X) of boron (B) to metal element (X), is 5.8 or more and 6.2. More preferably, it is as follows.

In addition, when boride particles are produced, the obtained powder containing boride particles is not composed only of boride particles having a single composition, but is a particle containing boride having a plurality of compositions. be able to. Specifically, for example, particles of a mixture of borides such as XB ₄ , XB ₆ , and XB ₁₂ can be used.

  Therefore, for example, when X-ray diffraction measurement is performed on hexaboride particles, which are typical boride particles, even in the case of a single phase, a very small amount is actually measured. It is thought that other phases are included.

Therefore, _m in the general formula XB _m of the boride particles of the present embodiment is, for example, obtained by chemical analysis of the obtained powder containing boride particles by ICP emission spectroscopy (high frequency inductively coupled plasma emission spectroscopy) or the like. In this case, the atomic ratio of boron (B) to one atom of X element can be used.

  The metal element (X) of the boride particles of the present embodiment is not particularly limited as shown in the general formula. For example, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy , Ho, Er, Tm, Yb, Lu, Sr, Ca can be used as one or more metal elements.

  However, since lanthanum hexaboride, which is a hexaboride of lanthanum, has particularly high near-infrared absorptivity, the boride particles of this embodiment preferably include lanthanum hexaboride particles.

  As described above, according to the study by the inventors of the present invention, boride particles that can be easily pulverized can be obtained by setting the carbon amount (carbon concentration) in the boride particles to a predetermined value or less. be able to. The reason for this will be described below.

  According to the study of the inventors of the present invention, the carbon contained in the boride particles may form a carbon compound with the component of the boride particles, or the carbon compound contained in the raw material may remain.

Examples of such a carbon compound include LaB ₂ C ₂ , LaB ₂ C ₄ , B ₄ C, B _4.5 C, B _5.6 C, B _6.5 C, B _7.7 C, and B _9. C etc. are mentioned.

According to Non-Patent Document 1, among the above-mentioned carbon compounds, B ₄ C, B _4.5 C, B _5.6 C, B _6.5 C, B _7.7 C, and B ₉ C The Young's modulus as an index is a high hardness carbon compound of 472 GPa, 463 GPa, 462 GPa, 446 GPa, 352 GPa, and 348 GPa, respectively.

  On the other hand, Non-Patent Document 2 reports that, for example, the Young's modulus of lanthanum hexaboride is 194 GPa. In addition, it is presumed that other boride particles have similar Young's modulus.

  As described above, the carbon compound mixed as an impurity may have a higher Young's modulus than the target boride particles. For this reason, in order to obtain boride particles that can be easily pulverized, it is required to suppress the mixing of these carbon compounds.

  And since the mixing amount (content) of these carbon compounds has a correlation with the carbon amount in the boride particles, as described above, the carbon amount in the boride particles is set to a predetermined value or less, It is believed that boride particles can be easily pulverized.

  The amount of carbon contained in the boride particles of the present embodiment can be measured by a combustion-infrared absorption method. And it is preferable that it is 0.2 mass% or less, and, as for the carbon content contained in the boride particle | grains of this embodiment measured by the combustion-infrared absorption method, it is more preferable that it is 0.1 mass% or less.

Particularly, in the boride particles, B ₄ C (boron carbide) among the above-mentioned carbon compounds is easily generated, and therefore the boride particles of the present embodiment can suppress the amount of B ₄ C contained. preferable. For example, the B ₄ C content (content ratio) of the boride particles of the present embodiment is preferably 1.0% by mass or less.

By setting the amount of B ₄ C contained in the boride particles of the present embodiment, that is, the content ratio of B ₄ C to 1.0% by mass or less, the content of other carbon compounds can also be suppressed. The boride particles can be pulverized, which is preferable.

The amount of B ₄ C contained in the boride particles of the present embodiment can be measured by ICP analysis by performing a pretreatment of nitric acid dissolution and filtration separation.

It is known that B ₄ C hardly dissolves in nitric acid. On the other hand, boride particles are known to dissolve in nitric acid.

Therefore, when evaluating the amount of B ₄ C in the boride particles, the boride particles are added to nitric acid, the boride particles are dissolved, and then the undissolved residue is separated by filtration, whereby the B in the boride particles is separated. Only ₄ C particles can be removed. Then, the separated B _{4 C} particles were dissolved by sodium carbonate, by measuring the boron concentration by ICP analysis, it is possible to calculate the B 4 _C concentration.

At this time, in order to confirm that the undissolved residue obtained after the filtration and separation is B ₄ C, a sample that was processed in the same way until the filtration and separation was prepared in parallel, and the sample obtained after the filtration and separation was prepared. It is desirable to confirm that the undissolved residue is a B ₄ C single phase by XRD measurement.

  By the way, boride particles such as hexaboride particles are a powder colored dark blue-purple, etc., but pulverized so that the particle size is sufficiently smaller than the wavelength of visible light, and in the state dispersed in the film, Visible light transparency occurs. At the same time, an infrared shielding function appears.

  Although the reason for this has not been elucidated in detail, these boride materials have a relatively large number of free electrons, and absorption due to interband transition between 4f-5d and electron-electron and electron-phonon interaction is near-red. It is thought that it originates in existing in an outside field.

  According to the experiment, in a film in which these boride particles are sufficiently finely and uniformly dispersed, the transmittance of the film has a maximum value in a wavelength range of 400 nm to 700 nm and a wavelength range of 700 nm to 1800 nm. It is confirmed to have a local minimum. Considering that the visible light wavelength is 380 nm or more and 780 nm or less and the visibility is a bell-shaped peak with a peak at around 550 nm, such a film effectively transmits visible light and other sunlight is effectively used. It can be understood that it absorbs and reflects.

  The average dispersed particle size of the boride particles of this embodiment is preferably 100 nm or less, and more preferably 85 nm or less.

  The lower limit of the average dispersed particle size of the boride particles is not particularly limited, but is preferably 1 nm or more, for example. This is because it is industrially difficult to make the average dispersed particle diameter of boride particles less than 1 nm.

  The average dispersed particle diameter here can be measured by a particle size measuring apparatus based on a dynamic light scattering method.

  Since the boride particles of the present embodiment described above have a carbon content of a predetermined value or less, they can be easily pulverized so that, for example, the average dispersed particle diameter is 100 nm or less, particularly 85 nm or less. For this reason, the infrared shielding optical member in which the boride particles of the present embodiment are dispersed can suppress the occurrence of blue haze even when strong light such as sunlight or spotlight is irradiated.

  Next, one structural example of the boride particle manufacturing method of the present embodiment will be described.

As a method for producing boride particles of the present embodiment, the obtained boride particles are represented by the general formula XB _m (where X is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho). , Er, Tm, Yb, Lu, Sr, Ca), and the amount of carbon contained in the boride particles when the boride particles are measured by a combustion-infrared absorption method If (carbon concentration) is 0.2 mass% or less, it will not specifically limit.

  As one configuration example of the method for producing boride particles of the present embodiment, for example, a solid phase reaction method using carbon or boron carbide as a reducing agent can be mentioned. Hereinafter, a case where boride particles using lanthanum as a metal element is manufactured will be described as an example.

  For example, boride particles using lanthanum as a metal element can be produced by firing a mixture of a boron source, a reducing agent, and a lanthanum source.

  Specifically, for example, when producing lanthanum boride particles using boron carbide as a boron source and a reducing agent and lanthanum oxide as a lanthanum source, first, a raw material mixture of boron carbide and lanthanum oxide is prepared. Next, the raw material mixture is baked at a temperature of 1500 ° C. or higher in an inert atmosphere, whereby lanthanum oxide is reduced by carbon in boron carbide, carbon monoxide and carbon dioxide are generated, and carbon is removed. . Furthermore, lanthanum boride is obtained from the remaining lanthanum and boron.

  In addition, carbon derived from boron carbide is not completely removed as carbon monoxide and carbon dioxide, but part of it remains in the lanthanum boride particles and becomes impurity carbon. Therefore, when the proportion of boron carbide in the raw material is increased, the impurity carbon concentration in the obtained lanthanum boride particles is increased.

As described above, the obtained powder containing boride particles is not composed only of boride particles having a single composition, but particles of a mixture with LaB ₄ , LaB ₆ , LaB ₁₂ and the like. Become. Therefore, when X-ray diffraction measurement is performed on the obtained powder containing boride particles, even if it is a single phase of boride in the analysis of X-ray diffraction, the other phase is actually contained in a trace amount. It is considered to contain.

  Here, when producing boride particles using lanthanum as a metal element as described above, the element ratio B / La of boron in the raw material boron source and lanthanum in the lanthanum source is not particularly limited. However, it is preferably 3.0 or more and 20.0 or less.

In particular, when the element ratio B / La of boron in the source boron source and the lanthanum element in the lanthanum source is 4.0 or more, the production of LaB, LaB _{2 and the} like can be suppressed. Moreover, although the reason is not clear, the solar radiation shielding characteristic can be improved.

  On the other hand, when the element ratio B / La of boron in the raw material boron source and lanthanum in the lanthanum source is 6.2 or less, generation of boron oxide particles in addition to boride particles is suppressed. Since boron oxide particles are hygroscopic, if boron oxide particles are mixed into the powder containing boride particles, the moisture resistance of the powder containing boride particles decreases, and the solar radiation shielding characteristics deteriorate over time. .

  For this reason, it is preferable to suppress the generation of boron oxide particles by setting the element ratio B / La of boron in the raw material boron source and lanthanum in the lanthanum source to 6.2 or less. Further, when the element ratio B / La is 6.2 or less, the content ratio of the hexaboride having particularly excellent solar radiation shielding characteristics can be increased, and the solar radiation shielding characteristics are improved, which is preferable.

  In order to further reduce the impurity carbon concentration, it is effective to reduce the proportion of boron carbide in the raw material as much as possible. Thus, for example, by generating lanthanum boride particles with B / La of 6.2 or less, a powder containing lanthanum boride particles having an impurity carbon concentration of 0.2 mass% or less can be obtained more reliably.

  As described above, when boride particles using lanthanum as a metal element are produced, the element ratio (molar ratio) B / La between boron in the boron source and lanthanum in the lanthanum source is 4.0 or more and 6 .2 or less is more preferable. By making the composition of the raw material within the above range, the powder containing lanthanum boride particles that can suppress the impurity carbon concentration in the powder containing the lanthanum boride particles obtained and at the same time exhibits high solar shading properties is obtained. be able to.

In particular, the particles of lanthanum boride obtained is preferably LaB ₆ is in principal. This is because LaB ₆ has particularly high near infrared absorption ability.

  For this reason, the element ratio B / La of boron in the source boron source and the lanthanum element in the lanthanum source is more preferably 5.8 or more and 6.2 or less.

  In addition, although the case where the boron source and the reducing agent were used to produce the lanthanum boride particles by using boron carbide as the lanthanum source and the lanthanum oxide as the lanthanum source was described as an example, the embodiment is not limited thereto. For example, boron or boron oxide can be used as the boron source, carbon can be used as the reducing agent, and lanthanum oxide can be used as the lanthanum source. In this case, it is preferable to perform a preliminary test or the like so as to select a mixing ratio of each component so that excess carbon or oxygen does not remain in the product.

  For example, according to the metal element X which the boride particle | grains to manufacture contain, the compound containing the metal element X instead of a lanthanum oxide can also be used. Examples of the compound containing the metal element X include one or more selected from a hydroxide of the metal element X, a hydrate of the metal element X, and an oxide of the metal element X. The method for producing the compound containing the metal element X is not particularly limited. For example, a solution containing the compound containing the metal element X and an alkaline solution are reacted with stirring to generate a precipitate, and the precipitate is obtained from the precipitate. be able to.

  As described above, even in the case of using a compound containing the metal element X instead of lanthanum oxide, a preliminary test or the like is performed so that excess carbon or oxygen does not remain in the product, and the mixing ratio of each component Is preferably selected. For example, the element ratio of boron in the boron source and the metal element X in the metal element X source may be the same as the element ratio of the boron in the boron source and the lanthanum element in the lanthanum source. it can.

The obtained boride particles can be formed into boride particles having a desired average dispersed particle size by, for example, wet grinding.
(2) Binder Since the coating layer can contain a binder as described above, the binder will be described next.

  As the binder, for example, an ultraviolet (UV) curable resin, a thermoplastic resin, a thermosetting resin, an electron beam curable resin, a room temperature curable resin, or the like can be selected according to the purpose. In particular, the binder preferably contains one or more selected from ultraviolet (UV) curable resins, thermoplastic resins, thermosetting resins, and room temperature curable resins.

  Specific examples of the binder include polyethylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polystyrene resin, polypropylene resin, ethylene vinyl acetate copolymer, polyester resin, polyethylene terephthalate resin, fluorine resin, polycarbonate. Resin, acrylic resin, polyvinyl butyral resin, etc. are mentioned.

  As the binder, for example, one type selected from the above resin group, or a combination of two or more types can be used. However, as the binder for the coating layer, it is particularly preferable to use a UV curable resin from the viewpoints of productivity, apparatus cost, and the like among the resin group described above.

  Further, an inorganic binder using a metal alkoxide can be used instead of the resin-based binder. Examples of the metal alkoxide include alkoxides such as Si, Ti, Al, and Zr as typical materials. An inorganic binder using these metal alkoxides can be subjected to hydrolysis and polycondensation by heating or the like to form a coating layer of an oxide film.

Further, the resin binder and the inorganic binder may be mixed and used.
(3) Transparent base material The infrared shielding transparent base material of this embodiment can have a coating layer on at least one surface of a transparent base material. Then, the structural example of a transparent base material is demonstrated next.

  As the transparent substrate, for example, a transparent film substrate or a transparent glass substrate can be preferably used.

  The transparent film substrate is not limited to a film shape, and may be, for example, a board shape or a sheet shape. The material of the transparent film substrate is not particularly limited, but for example, one or more selected from polyester, acrylic, urethane, polycarbonate, polyethylene, ethylene vinyl acetate copolymer, vinyl chloride, fluorine resin, etc. Can be used. The transparent film substrate is preferably a polyester film, and more preferably a polyethylene terephthalate (PET) film.

  The transparent glass substrate is not particularly limited, and a transparent glass substrate such as silica glass or soda glass can be used.

  The surface of the transparent substrate is preferably subjected to a surface treatment in order to improve the coating property of the infrared shielding particle dispersion and the adhesion to the coating layer. Moreover, in order to improve the adhesiveness of a transparent base material and a coating layer, an intermediate | middle layer can be formed on a transparent base material and a coating layer can also be formed on an intermediate | middle layer. The configuration of the intermediate layer is not particularly limited, and may be composed of, for example, a polymer film, a metal layer, an inorganic layer (for example, an inorganic oxide layer such as silica, titania, zirconia), an organic / inorganic composite layer, or the like. .

  As described above, the infrared shielding transparent substrate of the present embodiment has a coating layer on at least one surface of the transparent substrate, and the coating layer can include infrared shielding particles and a binder.

  Although a coating layer may be comprised only from the infrared shielding particle and the binder, it can also contain another component. For example, as described later, the coating layer can be manufactured using an infrared shielding particle dispersion, and a solvent, a dispersant, a coupling agent, a surfactant, and the like are added to the infrared shielding particle dispersion. be able to. For this reason, the coating layer may contain an additive component to the infrared shielding particle dispersion and a component derived from the additive component.

  Further, in order to further impart an ultraviolet shielding function to the infrared shielding transparent substrate of the present embodiment, the coating layer is selected from particles such as inorganic titanium oxide, zinc oxide, cerium oxide, organic benzophenone, benzotriazole, and the like. At least one kind of ultraviolet shielding material may be added.

  In addition, the said ultraviolet shielding material is not limited to the form added to a coating layer, The layer containing a ultraviolet shielding material can also be formed separately. In the case of forming a layer containing an ultraviolet shielding material, the arrangement of the layer is not particularly limited. For example, the layer can be formed on a coating layer.

  In addition, in order to improve the visible light transmittance of the infrared shielding transparent base material according to this embodiment, one or more kinds of particles selected from ATO, ITO, aluminum-added zinc oxide, and indium tin composite oxide are applied to the coating layer. Further, it may be mixed. By adding these transparent particles to the coating layer, the transmittance near a wavelength of 750 nm is increased, while infrared light having a wavelength longer than 1200 nm is shielded, so that the transmittance of near infrared light is high, and heat rays A heat ray shield with high shielding properties can be obtained. Note that one or more types of particles selected from the ATO and the like are not limited to the form added to the coating layer, and a layer containing such particles can be formed separately from the coating layer.

  Although the thickness of the coating layer on a transparent base material is not specifically limited, It is preferable that it is 20 micrometers or less practically, and it is more preferable that it is 6 micrometers or less. If the thickness of the coating layer is 20 μm or less, in addition to exhibiting sufficient pencil hardness and scratch resistance, the substrate film warps when the coating layer is stripped of the solvent and the binder is cured. This is because occurrence of process abnormality such as occurrence can be avoided.

  In addition, the lower limit value of the thickness of the coating layer is not particularly limited, but for example, is preferably 10 nm or more, and more preferably 50 nm or more.

The content of the infrared shielding particles contained in the coating layer is not particularly limited, but the content per projected area of the transparent substrate / coating layer is 0.01 g / m ² or more and 1.0 g / m ² or less. Is preferred. If the content is 0.01 g / m ² or more, the heat ray shielding characteristic can be exhibited significantly as compared with the case where the infrared shielding particles are not contained, and if the content is 1.0 g / m ² or less, the infrared ray is exhibited. This is because the shielding transparent substrate can sufficiently maintain the transmittance of visible light.

  In addition, the infrared shielding transparent base material of the present embodiment has a wavelength region of 360 nm to 500 nm when the visible light (wavelength 400 nm to 780 nm) transmittance of the coating layer is set to 45% to 55%. It is preferable that the maximum value of the diffuse transmission profile is 1.5% or less.

  In addition, when a transparent base material having sufficient visible light transmittance is used and the transparent base material hardly affects the visible light transmittance of the infrared shielding transparent base material, that is, for example, a visible light transmittance of 90% or more. When using the transparent base material which has, you may read the visible light transmittance | permeability of the said coating layer with the visible light transmittance | permeability of an infrared shielding transparent base material.

  Here, a blue haze evaluation method will be described.

  There is no known method for directly measuring blue haze. However, the applicant of the present invention pays attention to linear incident light and scattered light as components of transmitted light when light is applied to the infrared shielding particle dispersion as a sample, and obtains diffuse transmittance for each wavelength. A method for evaluating "blue haze" has already been proposed (see Japanese Patent Application Laid-Open No. 2009-150979). Hereinafter, the principle of measuring the diffuse transmittance for each wavelength, that is, the diffuse transmission profile will be described with reference to FIGS.

  First, a measuring apparatus for measuring a diffuse transmission profile will be described with reference to FIGS. 1 and 2.

  As shown in FIGS. 1 and 2, the measuring apparatus 10 includes an integrating sphere 14. The integrating sphere 14 has a diffused reflectivity on the inner surface of the spherical body, and a second opening 141 to which the measurement sample 12 (see FIG. 2) is attached, the standard reflector 15 or the light trap component 16 is attached. It has the opening part 142 and the 3rd opening part 143 to which the light receiver 13 is attached.

  A light source 11 that emits linear light that enters the spherical space through the first opening 141; and a spectroscope (not shown) that is attached to the light receiver 13 and that separates the received reflected or scattered light. A data storage means (not shown) that is connected to the spectrometer and stores spectral data of the reflected or scattered light that is spectrally dispersed, and the diffuse transmitted light intensity from the stored spectral data of the blank transmitted light intensity and the diffuse transmitted light intensity. And a calculation means (not shown) that obtains the diffuse transmittance for each wavelength by calculating the ratio of each of the transmitted light intensity and the blank transmitted light intensity.

  Here, the integrating sphere 14 has a diffuse reflection property by applying barium sulfate or Spectralon (registered trademark) or the like to the inner surface of the spherical main body, and the incident angle to the standard reflector 15 is the standard side, the control. Both sides can be, for example, 10 °. As the light receiver 13, for example, a photomultiplier tube (ultraviolet / visible region) or a cooled lead sulfide (near infrared region) can be used. In addition, a spectroscope (not shown) attached to the light receiver 13 requires a wavelength measurement range in the ultraviolet / visible region and photometric accuracy (± 0.002 Abs).

  Next, as the light source 11 that emits linear light that enters the spherical space, for example, a deuterium lamp can be applied in the ultraviolet region, and a 50 W halogen lamp can be applied in the visible / near infrared region.

  The standard reflector 15 can be a white plate made of, for example, Spectralon, and the light trap component 16 must have a function of trapping incident linear light without reflecting it. For example, a dark box that absorbs incident linear light almost completely is used.

  Then, using the diffuse transmission profile measuring device, the maximum value of the diffuse transmission profile of the infrared shielding transparent base material or the like that is the measurement sample is determined as the blank transmitted light intensity measuring step, the diffuse transmitted light intensity measuring step, and the diffuse transmission. It can evaluate by each process with a rate calculation process.

  First, in the blank transmitted light intensity measurement step, the standard reflector 15 is attached to the second opening 142 of the integrating sphere 14 and the measurement sample is not attached to the first opening 141 as shown in FIG. Are incident on the spherical space through the first opening 141. Then, the reflected light reflected by the standard reflecting plate 15 is received by the light receiver 13 and dispersed by a spectroscope (not shown) attached to the light receiver 13 to obtain spectral data of the reflected light. The spectral data at this time is the blank transmitted light intensity.

  Next, in the diffuse transmitted light intensity measurement step, the light trap component 16 is attached to the second opening 142 of the integrating sphere 14 as shown in FIG. Then, with the measurement sample 12 attached to the first opening 141, linear light from the light source 11 enters the spherical space through the measurement sample 12 and the first opening 141 and is trapped by the light trap component 16. The scattered light other than the received light is received by the light receiver 13. At this time, the spectral data of the scattered light is obtained by performing spectroscopy with a spectroscope (not shown) attached to the light receiver 13. The spectral data at this time is the diffused transmitted light intensity.

  Then, in the diffuse transmittance calculation step, based on the spectral data of the blank transmitted light intensity and the diffuse transmitted light intensity stored by the data storage means (not shown) not shown, While calculating the ratio of the blank transmitted light intensity for each wavelength to obtain the diffuse transmittance for each wavelength, the maximum in the wavelength range of 360 nm to 500 nm in the diffuse transmission profile of the measurement sample 12 from the obtained diffuse transmittance for each wavelength. The value can be determined.

  Here, in the measuring apparatus that measures the diffuse transmission profile, an optical system for adjusting the light beam may be provided between the light source 11 and the measurement sample 12. In this optical system, for example, parallel light is adjusted by combining a plurality of lenses, and the amount of light is adjusted by a diaphragm. In some cases, a specific wavelength may be cut by a filter.

  And the infrared shielding transparent base material of this embodiment has a wavelength of 360 nm when the visible light (wavelength of 400 nm or more and 780 nm or less) transmittance of the coating layer is set to any of 45% or more and 55% or less as described above. The maximum value of the diffuse transmission profile in the region of 500 nm or less is preferably 1.5% or less. This is because it has been confirmed that almost no blue haze is observed in the infrared shielding transparent base material that satisfies the above conditions.

  The reason why the visible light transmittance of the coating layer is set to 45% or more and 55% or less is to specify the measurement condition of the diffuse transmittance (diffuse transmittance profile), and the diffuse transmittance is the visible light transmittance. The range is set to be proportional to. The reason why the diffuse transmittance (diffuse transmittance profile) in the region of wavelength 360 nm or more and 500 nm or less is measured is that scattering in that region is the cause of blue haze. If the maximum value of the diffuse transmittance in the above range is 1.5% or less, no blue haze is experimentally observed.

  The infrared shielding transparent substrate of the present embodiment can be used for various optical members, for example, and can be an infrared shielding optical member including the infrared shielding transparent substrate of the present embodiment.

  As an infrared shielding optical member here, the window of a building, the window of a motor vehicle, etc. are mentioned, for example.

According to the infrared shielding transparent base material of the present embodiment described above and the infrared shielding optical member including the infrared shielding transparent base material, the infrared shielding transparent base using boride particles that can be easily pulverized. It can be a material. For this reason, the average dispersed particle diameter of the infrared shielding particles contained in the coating layer can be made sufficiently small, and the occurrence of blue haze can be suppressed.
(Infrared shielding transparent substrate manufacturing method)
The infrared shielding transparent base material of this embodiment can be manufactured using, for example, an infrared shielding particle dispersion. Therefore, here, the infrared shielding particle dispersion and the manufacturing method thereof will be described first.
(1) Infrared shielding particle dispersion and method for producing the same As described above, the infrared shielding transparent substrate according to the present embodiment uses an infrared shielding particle dispersion containing boride particles, which are infrared shielding particles described so far. Can be manufactured. For this reason, here, a configuration example of the infrared shielding particle dispersion and the manufacturing method thereof will be described.

  The infrared shielding particle dispersion is obtained by dispersing the aforementioned infrared shielding particles in a solvent. The infrared shielding particle dispersion is prepared by adding the above-described infrared shielding particles, that is, boride particles, an appropriate amount of a dispersant, a coupling agent, a surfactant, and the like to a solvent for dispersion treatment. It can be obtained by dispersing the infrared shielding particles in a solvent.

  The solvent of the infrared shielding particle dispersion liquid is required to have a function for maintaining the dispersibility of the infrared shielding particles and a function for preventing application defects when the dispersion liquid is applied.

  Specifically, alcohol solvents such as methanol (MA), ethanol (EA), 1-propanol (NPA), isopropanol (IPA), butanol, pentanol, benzyl alcohol, diacetone alcohol, acetone, methyl ethyl ketone (MEK) , Ketone solvents such as methyl propyl ketone, methyl isobutyl ketone (MIBK), cyclohexanone, isophorone, ester solvents such as 3-methyl-methoxy-propionate (MMP), ethylene glycol monomethyl ether (MCS), ethylene glycol monoethyl ether (ECS), ethylene glycol isopropyl ether (IPC), propylene glycol methyl ether (PGM), propylene glycol ethyl ether (PE), propylene glycol methyl Glycol derivatives such as ether acetate (PGMEA), propylene glycol ethyl ether acetate (PE-AC), formamide (FA), N-methylformamide, dimethylformamide (DMF), dimethylacetamide, N-methyl-2-pyrrolidone ( Amides such as NMP), aromatic hydrocarbons such as toluene and xylene, and halogenated hydrocarbons such as ethylene chloride and chlorobenzene, etc., one or more selected from these Can be used in combination.

  Among the above, as the solvent, those having high hydrophobicity such as ketones such as MIBK and MEK, aromatic hydrocarbons such as toluene and xylene, glycol ether acetates such as PGMEA and PE-AC are more preferable. . For this reason, it is more preferable to use a combination of one or more selected from these.

  In order to form a coating layer on a transparent substrate such as a transparent film substrate or a transparent glass substrate, it is preferable to select an organic solvent having a low boiling point as a solvent. This is because if the solvent is an organic solvent having a low boiling point, the solvent can be easily removed in the drying step after coating, and properties of the coating layer, such as hardness and transparency, are not impaired.

  Specifically, it is preferable to use one kind selected from ketones such as methyl isobutyl ketone and methyl ethyl ketone, and aromatic hydrocarbons such as toluene and xylene, or a combination of two or more kinds.

  Dispersing agents, coupling agents, and surfactants can be selected according to the application, but have amine-containing groups, hydroxyl groups, carboxyl groups, or epoxy groups as functional groups. Is preferred. These functional groups are adsorbed on the surface of the infrared shielding particles and prevent aggregation of the infrared shielding particles, so that when the coating layer is formed on the transparent substrate, the infrared shielding particles are uniformly distributed in the coating layer. Demonstrate the effect of dispersing.

  As a dispersant, a coupling agent, and a surfactant, a phosphate ester compound, a polymer dispersant, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, and the like can be suitably used. .

  Examples of the polymer dispersant include acrylic polymer dispersants, urethane polymer dispersants, acrylic / block copolymer polymer dispersants, polyether dispersants, and polyester polymer dispersants. .

  However, the dispersant, the coupling agent, and the surfactant are not limited to these, and various dispersants, coupling agents, and surfactants can be used.

  The addition amount of one or more materials selected from a dispersant, a coupling agent, and a surfactant to the infrared shielding particle dispersion is 10 parts by weight or more and 1000 parts by weight per 100 parts by weight of boride particles that are infrared shielding particles. The range is preferably not more than parts by weight, more preferably not less than 20 parts by weight and not more than 200 parts by weight.

  If the added amount of the dispersant or the like is within the above range, the infrared shielding particles will not aggregate in the dispersion, and dispersion stability is maintained.

  The method for dispersing boride particles, which are infrared shielding particles, in the liquid medium is not particularly limited. For example, a method of dispersing the raw material mixture of the infrared shielding particle dispersion using a wet medium mill such as a bead mill, a ball mill, or a sand mill can be used. In particular, the infrared shielding particle dispersion of the present embodiment preferably has a state in which infrared shielding particles having an average dispersed particle diameter of 100 nm or less are dispersed in a liquid medium, and the average dispersed particle diameter of the infrared shielding particles is 85 nm. The following is more preferable. Therefore, it is preferable to prepare a dispersion by dispersing boride particles by a wet pulverization method using a medium stirring mill such as a bead mill.

  In order to obtain a uniform infrared shielding particle dispersion, various additives and dispersants may be added or the pH may be adjusted.

  The content of the infrared shielding particles in the infrared shielding particle dispersion described above is preferably 0.01% by mass or more and 30% by mass or less. This is because if the content of the infrared shielding particles is 0.01% by mass or more, a coating layer having an infrared shielding ability can be formed on the transparent substrate. Moreover, if the content of the infrared shielding particles is 30% by mass or less, the infrared shielding dispersion liquid can be easily applied onto the transparent substrate, and the productivity of the coating layer can be increased.

  The infrared shielding particles in the infrared shielding particle dispersion are preferably dispersed with an average dispersed particle size of 100 nm or less, and more preferably 85 nm or less. If the average dispersed particle diameter of the infrared shielding particles is 100 nm or less, the generation of blue haze in the infrared shielding transparent substrate produced using the infrared shielding particle dispersion according to the present embodiment is suppressed, and the optical characteristics are improved. Because it can. Moreover, it is because generation | occurrence | production of the blue haze in an infrared shielding transparent base material can be suppressed especially when this average dispersed particle diameter is 85 nm or less.

  When an infrared shielding particle dispersion is prepared using the boride particles described above, the average dispersed particle size is 100 nm efficiently without causing problems such as gelation of the infrared shielding particle dispersion (slurry). In the following, the inventors of the present invention infer that the reason why pulverization is possible to 85 nm or less is as follows.

  Since the boride particles are hard, when they are pulverized using a wet medium agitation mill, wear debris such as fine powder with worn media beads and fine bead pieces with broken media beads are mixed in the slurry. At this time, since the hardness of boride particles increases with an increase in carbon concentration, when boride particles having a carbon concentration higher than 0.2% by mass are used as raw materials, a large amount of media beads wear residue is slurried. It gets mixed in. The wear debris of the media beads increases the viscosity of the slurry.

On the other hand, by using boride particles having a carbon concentration of 0.2% by mass or less as a raw material, when the average dispersed particle size is pulverized to 100 nm or less, particularly 85 nm or less, media beads wear debris is mixed. Since the amount is greatly reduced, it is assumed that the slurry can be efficiently pulverized without deteriorating the viscosity of the slurry. However, there are many unexplained points about the increase in the viscosity of the slurry, and there is a possibility that actions other than those described above are working, and therefore, it is not limited to the above actions.
(2) Manufacturing method of infrared shielding transparent base material Next, one structural example of the manufacturing method of the infrared shielding transparent base material of this embodiment is demonstrated.

  The infrared shielding transparent substrate of the present embodiment can be produced by forming a coating layer containing infrared shielding particles on the transparent substrate using the above-described infrared shielding particle dispersion. An example of a specific procedure will be described below.

  A binder is added to the above-described infrared shielding particle dispersion to obtain a coating solution.

  After coating the obtained coating liquid on the surface of the transparent substrate, the coating layer in which the infrared shielding particles are dispersed in the medium can be formed by evaporating the solvent and curing the binder by a predetermined method.

  In addition, without adding a binder to the infrared shielding particle dispersion, to prepare a coating solution having a concentration adjusted, coated on a transparent substrate, evaporate the solvent, and then overcoat the coating solution containing the binder, The coating layer may be formed by evaporating the solvent.

  Since the binder and the transparent substrate that can be suitably used for the coating layer have already been described, the description thereof is omitted here.

  The surface of the transparent substrate is preferably subjected to a surface treatment in order to improve the coating property of the infrared shielding particle dispersion and the adhesion to the coating layer. Moreover, in order to improve the adhesiveness of a transparent base material and a coating layer, an intermediate | middle layer can be formed on a transparent base material and a coating layer can also be formed on an intermediate | middle layer. The configuration of the intermediate layer is not particularly limited, and may be composed of, for example, a polymer film, a metal layer, an inorganic layer (for example, an inorganic oxide layer such as silica, titania, zirconia), an organic / inorganic composite layer, or the like. .

  The method of providing the coating layer on the transparent substrate is not particularly limited as long as the infrared shielding particle dispersion can be uniformly applied to the surface of the transparent substrate. Examples thereof include a bar coating method, a gravure coating method, a spray coating method, and a dip coating method.

  For example, when a UV curable resin is used as the binder contained in the infrared shielding particles and the coating layer is formed using the bar coating method, the liquid concentration and additives are appropriately adjusted so that the infrared shielding particle dispersion has an appropriate leveling property. It is preferable to keep it. Then, the wire number of the bar number is selected so that the thickness of the coating layer and the content of the infrared shielding particles can achieve the purpose of the obtained infrared shielding transparent substrate, and a coating film is formed on the transparent substrate. be able to.

  Next, after removing the organic solvent contained in the coating film by drying, the coating layer can be formed on the transparent substrate by irradiating and curing with ultraviolet rays. At this time, although the drying conditions of the coating film vary depending on the components, the types of solvents and the use ratio, for example, the coating can be performed by heating at a temperature of 60 ° C. to 140 ° C. for about 20 seconds to 10 minutes. There is no restriction | limiting in particular in the irradiation method of an ultraviolet-ray, For example, UV exposure machines, such as an ultrahigh pressure mercury lamp, can be used suitably.

  In addition, the adhesiveness between the transparent substrate and the coating layer, the smoothness of the coating film during coating, the drying property of the organic solvent, and the like can be manipulated by the steps before and after the formation of the coating layer. Examples of the pre- and post-process include a surface treatment process for a transparent substrate, a pre-bake (substrate pre-heating) process, a post-bake (substrate post-heating) process, and the like, and can be selected as appropriate. The heating temperature in the pre-bake process and / or the post-bake process is preferably 80 ° C. or higher and 200 ° C. or lower, and the heating time is preferably 30 seconds or longer and 240 seconds or shorter.

  Since the preferred range of the thickness of the coating layer to be formed and the content of the infrared shielding particles in the coating layer has already been described, the description thereof is omitted here.

  In addition, in order to further impart an ultraviolet shielding function to the infrared shielding transparent base material of this embodiment, the coating layer has at least one particle such as inorganic titanium oxide, zinc oxide, cerium oxide, organic benzophenone, benzotriazole, or the like. More than one type may be added.

  In addition, in order to improve the visible light transmittance of the infrared shielding transparent base material according to this embodiment, one or more kinds of particles selected from ATO, ITO, aluminum-added zinc oxide, and indium tin composite oxide are applied to the coating layer. Further, it may be mixed. By adding these transparent particles to the coating layer, the transmittance near a wavelength of 750 nm is increased, while infrared light having a wavelength longer than 1200 nm is shielded, so that the transmittance of near infrared light is high, and heat rays A heat ray shield with high shielding properties can be obtained.

  According to the manufacturing method of the infrared shielding transparent base material of this embodiment demonstrated above, the infrared shielding transparent base material using the boride particle | grains which can be pulverized easily can be manufactured. According to the infrared shielding transparent base material, the average dispersed particle diameter of the infrared shielding particles contained in the coating layer can be sufficiently reduced, and the generation of blue haze can be suppressed.

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

Here, first, evaluation methods of samples in the following examples and comparative examples will be described.
(Boride particle composition)
The following examples, the boride particles obtained in Comparative Example, ICP (Shimadzu Model: ICPE9000) was analyzed using a boron to metal element X when expressed by the general formula XB _m in (B) The value of m, which is the element ratio (B / X) of boron (B) and metal element X in the boride particles, was calculated.
(Carbon concentration in boride particles)
The amount of carbon (carbon concentration) in the boride particles produced in the following examples and comparative examples was measured by a combustion-infrared absorption method.
(B ₄ C concentration in boride particles)
Among the obtained boride particles, the sample for measuring the B ₄ C concentration was divided into two, each weighed in a platinum crucible, 7N nitric acid was added and heated to 50 ° C. to dissolve the boride particles. . After standing to cool, pure water was added, and the undissolved residue (B ₄ C) was separated by filtration through a cellulose acetate membrane filter having a pore size of 0.2 μm.

  One undissolved residue obtained was put in the original platinum crucible, wetted with a saturated aqueous solution of calcium hydroxide to prevent volatilization of boron, and then dried in a dryer at about 80 ° C. After drying, sodium carbonate was added and mixed well before melting. After standing to cool, the molten salt in the crucible was dissolved in warm water and transferred to a Teflon (registered trademark) beaker. After adding nitric acid, the sample was heated and boiled to remove carbon dioxide, and then used as a sample solution for ICP. The boron concentration in the obtained sample solution was analyzed by ICP.

Also, other undissolved residue obtained subjected to XRD measurement for undissolved residue was confirmed whether the B _{4 C} single phase. When it was a B ₄ C single phase, the B ₄ C concentration was calculated from the boron concentration analyzed by ICP.
(Visible light transmittance)
The visible light transmittance in the following examples and comparative examples is the ratio of the transmitted light beam to the incident light beam with respect to the daylight beam perpendicularly incident on the sample. Here, the daylight means CIE daylight defined by the International Lighting Commission. In this CIE daylight, the spectral illuminance distribution of daylight having the same color temperature as the color temperature of blackbody radiation is shown as a relative value with respect to the value of wavelength 560 nm based on the observation data. The luminous flux is obtained by integrating the numerical value of the product of the value of the radiant flux for each wavelength of radiation and the visibility (sensitivity to the light of the human eye) with respect to the wavelength. That is, the visible light transmittance is a value that means the brightness perceived by the human eye by the integrated value of the transmitted light amount obtained by standardizing the light transmission amount in the wavelength region of 380 nm or more and 780 nm or less by the visibility of the human eye. .

The transmittance is measured using a spectrophotometer (Model: U-4100 manufactured by Hitachi, Ltd.) at an interval of 1 nm in a wavelength range of 300 nm to 2600 nm.
(Maximum diffuse transmission profile)
About the infrared shielding transparent base materials produced in the following examples and comparative examples, a spectrophotometer (Hitachi, Ltd. model: U-4100) was used as a spectroscope, and the method described with reference to FIGS. The diffuse transmittance was measured at intervals of 1 nm in the wavelength range of 300 nm to 800 nm. And the maximum value was calculated | required from the obtained diffuse transmission profile.
(Haze)
The haze value of the infrared shielding transparent base material was measured based on JIS K 7105-1981 using a haze meter (Murakami Color Research Laboratory Model: HM-150).
(Average dispersed particle size)
The average dispersed particle size was measured by a particle size measuring device based on a dynamic light scattering method (model: ELS-8000 manufactured by Otsuka Electronics Co., Ltd.). The particle refractive index was 1.81, and the particle shape was non-spherical. The background was measured with toluene, and the solvent refractive index was 1.50.
(Blue haze)
The blue haze was confirmed by irradiating an artificial solar lamp [XC-100 manufactured by Celic Co., Ltd.] to the infrared shielding transparent base material produced in the following examples and comparative examples.

Hereinafter, sample preparation conditions and evaluation results in each example and comparative example will be described.
[Example 1]
Boron carbide was used as a boron source and a reducing agent, and lanthanum oxide was used as a lanthanum source. These were weighed and mixed so that B / La, which is the element ratio of lanthanum and boron, was 5.90. Thereafter, it was calcined for 6 hours under a temperature condition of 1600 ± 50 ° C. in an argon atmosphere to obtain a powder containing lanthanum hexaboride particles.

The carbon content of the obtained lanthanum hexaboride particle-containing powder was measured by a combustion-infrared absorption method, and the carbon content was 0.05% by mass. Further, when the composition of the obtained lanthanum hexaboride particles was evaluated by ICP, m, which is the elemental ratio (B / La) of boron (B) to lanthanum element (La) in the general formula LaB _m , It was confirmed that it was 5.8.

Further, the obtained lanthanum hexaboride particle-containing powder was measured for the B ₄ C concentration of the lanthanum hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above. It was 2 mass%.

  Next, the produced lanthanum hexaboride particle-containing powder (infrared shielding material) is in a ratio of 10 parts by weight, toluene 80 parts by weight, and dispersant (acrylic polymer dispersant having an amino group) 10 parts by weight. Weighed and mixed to prepare 3 kg slurry. This slurry was put into a medium stirring mill together with the beads, and the slurry was circulated, and pulverized and dispersed for 20 hours.

The medium stirring mill used was a horizontal cylindrical annular type (manufactured by Ashizawa Corporation), and the material of the inner wall of the vessel and the rotor (rotating stirring portion) was ZrO ₂ . In addition, beads made of YSZ (Ytria-Stabilized Zirconia) having a diameter of 0.3 mm were used as the beads. The rotation speed of the rotor was 13 m / sec, and the slurry was pulverized at a slurry flow rate of 1 kg / min. The average dispersed particle size of boride particles in the obtained dispersion was measured and found to be 70 nm.

  Furthermore, the obtained dispersion, UV curable resin, and toluene were mixed at a weight ratio of dispersion: UV curable resin: toluene = 2: 1: 1 to prepare a coating solution. This was coated on a transparent glass substrate with a bar coater to form a coating film. At this time, the bar used for coating was selected so that the visible light transmittance of the resulting coating layer was about 50%. The IMC-700 manufactured by Imoto Seisakusho was used as the bar coater, and the thickness of the coating layer obtained was about 10 μm.

  Next, the solvent was evaporated from the coating film by holding at 70 ° C. for 1 minute, and then the coating film was cured by irradiation with ultraviolet rays. And the optical characteristic of the obtained infrared shielding transparent base material was measured. The measurement results are shown in Table 1 below.

The haze of the obtained infrared shielding transparent base material was 0.2%, and it was confirmed that the transparency was extremely high. Moreover, the maximum value of the diffuse transmission profile in the region of wavelengths from 360 nm to 500 nm was 0.6%, and no blue haze was observed when artificial sunlight was irradiated.
[Example 2]
A lanthanum hexaboride particle-containing powder was obtained in the same manner as in Example 1 except that boron carbide and lanthanum oxide were weighed and mixed so that the element ratio B / La between lanthanum and boron was 5.95. .

When the carbon content of the obtained lanthanum hexaboride particle-containing powder was measured by a combustion-infrared absorption method, the carbon content was 0.1% by mass. Further, when the composition of the obtained lanthanum hexaboride particles was evaluated by ICP, m, which is the elemental ratio (B / La) of boron (B) to lanthanum element (La) in the general formula LaB _m , It was confirmed that it was 5.9.

Further, the obtained lanthanum hexaboride particle-containing powder was measured for the B ₄ C concentration of the lanthanum hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above. It was 5 mass%.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the lanthanum hexaboride particle-containing powder was used. Moreover, the infrared shielding transparent base material was produced using the obtained dispersion liquid.

Evaluation similar to Example 1 was performed about the obtained dispersion liquid and an infrared shielding transparent base material. The results are shown in Table 1.
[Example 3]
A lanthanum hexaboride particle-containing powder was obtained in the same manner as in Example 1 except that boron carbide and lanthanum oxide were weighed and mixed so that the element ratio B / La of lanthanum and boron was 6.00. .

When the carbon concentration of the obtained lanthanum hexaboride particle-containing powder was measured by a combustion-infrared absorption method, the carbon content was 0.2% by mass. Further, when the composition of the obtained lanthanum hexaboride particles was evaluated by ICP, m, which is the elemental ratio (B / La) of boron (B) to lanthanum element (La) in the general formula LaB _m , It was confirmed that it was 5.9.

Further, the obtained lanthanum hexaboride particle-containing powder was measured for the B ₄ C concentration of the lanthanum hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above. It was 9% by mass.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the lanthanum hexaboride particle-containing powder was used. Moreover, the infrared shielding transparent base material was produced using the obtained dispersion liquid.

Evaluation similar to Example 1 was performed about the obtained dispersion liquid and an infrared shielding transparent base material. The results are shown in Table 1.
[Example 4]
A lanthanum hexaboride particle-containing powder was obtained in the same manner as in Example 1 except that boron carbide and lanthanum oxide were weighed and mixed so that the element ratio B / La of lanthanum and boron was 6.10. .

When the carbon concentration of the obtained lanthanum hexaboride particle-containing powder was measured by a combustion-infrared absorption method, the carbon content was 0.2% by mass. Further, when the composition of the obtained lanthanum hexaboride particles was evaluated by ICP, m, which is the elemental ratio (B / La) of boron (B) to lanthanum element (La) in the general formula LaB _m , It was confirmed that it was 6.0.

Further, the obtained lanthanum hexaboride particle-containing powder was measured for the B ₄ C concentration of the lanthanum hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above. It was 9% by mass.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the lanthanum hexaboride particle-containing powder was used. Moreover, the infrared shielding transparent base material was produced using the obtained dispersion liquid.

Evaluation similar to Example 1 was performed about the obtained dispersion liquid and an infrared shielding transparent base material. The results are shown in Table 1.
[Example 5]
Boron carbide and lanthanum oxide were weighed and mixed so that the element ratio B / La of lanthanum to boron was 6.20, and the same as in Example 1 except that it was fired at a temperature of 1650 ± 50 ° C. A powder containing lanthanum hexaboride particles was obtained.

When the carbon concentration of the obtained lanthanum hexaboride particle-containing powder was measured by a combustion-infrared absorption method, the carbon content was 0.2% by mass. Further, when the composition of the obtained lanthanum hexaboride particles was evaluated by ICP, m, which is the elemental ratio (B / La) of boron (B) to lanthanum element (La) in the general formula LaB _m , It was confirmed that it was 6.0.

Further, the obtained lanthanum hexaboride particle-containing powder was measured for the B ₄ C concentration of the lanthanum hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above. It was 9% by mass.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the lanthanum hexaboride particle-containing powder was used. Moreover, the infrared shielding transparent base material was produced using the obtained dispersion liquid.

Evaluation similar to Example 1 was performed about the obtained dispersion liquid and an infrared shielding transparent base material. The results are shown in Table 1.
[Example 6]
Example 1 except that boron oxide was used as the boron source, lanthanum oxide was used as the lanthanum source, carbon (graphite) was used as the reducing agent, and the element ratio B / La between lanthanum and boron was 6.10. In the same manner as above, a powder containing lanthanum hexaboride particles was obtained. However, 60 parts by weight of carbon was weighed and mixed with 100 parts by weight of boron oxide.

When the carbon content of the obtained lanthanum hexaboride particle-containing powder was measured by a combustion-infrared absorption method, the carbon content was 0.1% by mass. Further, when the composition of the obtained lanthanum hexaboride particles was evaluated by ICP, m, which is the elemental ratio (B / La) of boron (B) to lanthanum element (La) in the general formula LaB _m , It was confirmed that it was 6.0.

Further, the obtained lanthanum hexaboride particle-containing powder was measured for the B ₄ C concentration of the lanthanum hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above. It was 4% by mass.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the lanthanum hexaboride particle-containing powder was used. Moreover, the infrared shielding transparent base material was produced using the obtained dispersion liquid.

Evaluation similar to Example 1 was performed about the obtained dispersion liquid and an infrared shielding transparent base material. The results are shown in Table 1.
[Example 7]
A cerium hexaboride particle-containing powder was obtained in the same manner as in Example 1 except that cerium oxide was used instead of lanthanum oxide so that the element ratio B / Ce of cerium and boron was 6.10. It was.

When the carbon concentration of the obtained cerium hexaboride particle-containing powder was measured by a combustion-infrared absorption method, the carbon content was 0.2% by mass. Also were evaluated by ICP for the composition of the obtained cerium hexaboride particles, in the general formula CeB _m, an element ratio of boron (B) with respect to the cerium element (Ce) (B / Ce) m, It was confirmed that it was 6.0.

Further, the cerium hexaboride particles containing powder obtained, where the evaluation method of B _{4 C} concentration in aforementioned boride particles were measured B _{4 C} concentration of cerium hexaboride particles containing powder, 0. It was 9% by mass.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the cerium hexaboride particle-containing powder was used. Moreover, the infrared shielding transparent base material was produced using the obtained dispersion liquid.

Evaluation similar to Example 1 was performed about the obtained dispersion liquid and an infrared shielding transparent base material. The results are shown in Table 1.
[Comparative Example 1]
Boron carbide was used as a boron source and a reducing agent, and lanthanum oxide was used as a lanthanum source. These were weighed and mixed so that the element ratio B / La of lanthanum and boron was 6.10. Thereafter, it was calcined in an argon atmosphere at a temperature of 1480 ± 50 ° C. for 6 hours to obtain a lanthanum hexaboride particle-containing powder.

When the carbon content of the obtained lanthanum hexaboride particle-containing powder was measured by a combustion-infrared absorption method, the carbon content was 0.6% by mass. Further, when the composition of the obtained lanthanum hexaboride particles was evaluated by ICP, m, which is the elemental ratio (B / La) of boron (B) to lanthanum element (La) in the general formula LaB _m , It was confirmed that it was 6.0.

Further, the obtained lanthanum hexaboride particle-containing powder was measured for the B ₄ C concentration of the lanthanum hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above. It was 6% by mass.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the lanthanum hexaboride particle-containing powder was used.

  Evaluation similar to Example 1 was performed about the obtained dispersion liquid. The results are shown in Table 1.

  In addition, in order to prepare the dispersion, the average dispersed particle size was 105 nm and larger than 100 nm at the time when the grinding treatment was performed for 20 hours. It was judged that it was difficult to obtain a particle size of 100 nm or less even if the process was continued.

  Using the obtained dispersion, a coating layer was formed on a transparent glass substrate in the same manner as in Example 1 to obtain an infrared shielding transparent substrate. And the optical characteristic of the obtained infrared shielding transparent base material was measured. The measurement results are shown in Table 1 below.

The haze of the obtained infrared shielding transparent base material was 1.6%, and it was confirmed that the transparency was very low. Moreover, the maximum value of the diffuse transmission profile in the wavelength region of 360 nm or more and 500 nm or less was 1.9%, and when the artificial sunlight was irradiated, blue haze was clearly confirmed visually.
[Comparative Example 2]
A lanthanum hexaboride particle-containing powder is obtained under the same conditions as in Comparative Example 1 except that boron carbide and lanthanum oxide are weighed and mixed so that the element ratio B / La between lanthanum and boron is 6.20. It was.

When the carbon content of the obtained lanthanum hexaboride particle-containing powder was measured by a combustion-infrared absorption method, the carbon content was 0.8% by mass. Further, when the composition of the obtained lanthanum hexaboride particles was evaluated by ICP, m, which is the elemental ratio (B / La) of boron (B) to lanthanum element (La) in the general formula LaB _m , It was confirmed to be 6.1.

Further, the obtained lanthanum hexaboride particle-containing powder was measured for the B ₄ C concentration of the lanthanum hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above. It was 7 mass%.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the lanthanum hexaboride particle-containing powder was used. Moreover, the coating layer was formed on the glass substrate similarly to the case of Example 1 using the obtained dispersion liquid. And the optical characteristic of the obtained infrared shielding transparent base material was measured. The measurement results are shown in Table 1 below.

The haze of the obtained infrared shielding transparent base material was 1.8%, and it was confirmed that the transparency was very low. Moreover, the maximum value of the diffuse transmission profile in the wavelength region of 360 nm or more and 500 nm or less is 2.4%, and when irradiated with artificial sunlight, blue haze is clearly visible as in Comparative Example 1. confirmed.
[Comparative Example 3]
Comparative Example, except that boron oxide was used as the boron source, lanthanum oxide was used as the lanthanum source, carbon (graphite) was used as the reducing agent, and the element ratio B / La between lanthanum and boron was 6.10. In the same manner as in No. 1, a powder containing lanthanum hexaboride particles was obtained. However, 60 parts by weight of carbon was weighed and mixed with 100 parts by weight of boron oxide.

The carbon content of the obtained lanthanum hexaboride particle-containing powder was measured by a combustion-infrared absorption method, and the carbon content was 0.7% by mass. Further, when the composition of the obtained lanthanum hexaboride particles was evaluated by ICP, m, which is the elemental ratio (B / La) of boron (B) to lanthanum element (La) in the general formula LaB _m , It was confirmed that it was 6.0.

Further, the obtained lanthanum hexaboride particle-containing powder was measured for the B ₄ C concentration of the lanthanum hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above. It was 4% by mass.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the lanthanum hexaboride particle-containing powder was used. Moreover, the coating layer was formed on the glass substrate similarly to the case of Example 1 using the obtained dispersion liquid. And the optical characteristic of the obtained infrared shielding transparent base material was measured. The measurement results are shown in Table 1 below.

The haze of the obtained infrared shielding transparent base material was 1.7%, and it was confirmed that the transparency was very low. Moreover, the maximum value of the diffuse transmission profile in the wavelength region of 360 nm or more and 500 nm or less is 2.2%, and when irradiated with artificial sunlight, blue haze is clearly visible as in Comparative Example 1. confirmed.
[Comparative Example 4]
A cerium hexaboride particle-containing powder was obtained in the same manner as in Comparative Example 1 except that cerium oxide was used instead of lanthanum oxide so that the element ratio B / Ce of cerium and boron was 6.10. It was.

When the carbon concentration of the obtained cerium hexaboride particle-containing powder was measured by a combustion-infrared absorption method, the carbon content was 0.9% by mass. Also were evaluated by ICP for the composition of the obtained cerium hexaboride particles, in the general formula CeB _m, an element ratio of boron (B) with respect to the cerium element (Ce) (B / Ce) m, It was confirmed that it was 6.0.

Furthermore, when the obtained cerium hexaboride particle-containing powder was measured for the B ₄ C concentration of the cerium hexaboride particle-containing powder by the method for evaluating the B ₄ C concentration in the boride particles described above, 4. It was 4% by mass.

  A boride particle dispersion was prepared in the same manner as in Example 1 except that the cerium hexaboride particle-containing powder was used. Moreover, the coating layer was formed on the glass substrate similarly to the case of Example 1 using the obtained dispersion liquid. And the optical characteristic of the obtained infrared shielding transparent base material was measured. The measurement results are shown in Table 1 below.

  The haze of the obtained infrared shielding transparent base material was 1.9%, and it was confirmed that the transparency was very low. Moreover, the maximum value of the diffuse transmission profile in the wavelength region of 360 nm or more and 500 nm or less is 2.5%, and when irradiated with artificial sunlight, blue haze is clearly visible as in Comparative Example 1. confirmed.

実施例１〜実施例７では、固相反応等により得られたホウ化物粒子を、比較的簡単かつ経済的に、平均分散粒子径を１００ｎｍ以下、特に８５ｎｍ以下にまで粉砕して微細化することができることが確認できた。また、実施例１〜実施例７では、得られるホウ化物粒子は平均分散粒子径が１００ｎｍ以下、特に８５ｎｍ以下となるため、その粒子または分散液を用いて作製したコーティング層を備えた赤外線遮蔽透明基材に人口太陽光を照射しても青白色に着色しない、すなわち、ブルーヘイズが抑制できることが確認される。

In Examples 1 to 7, boride particles obtained by a solid phase reaction or the like are pulverized and refined relatively easily and economically to an average dispersed particle size of 100 nm or less, particularly 85 nm or less. I was able to confirm. In Examples 1 to 7, since the boride particles obtained have an average dispersed particle size of 100 nm or less, particularly 85 nm or less, the infrared shielding transparent provided with a coating layer prepared using the particles or dispersion liquid It is confirmed that even if artificial sunlight is applied to the base material, it is not colored bluish white, that is, blue haze can be suppressed.

  Therefore, it turns out that the infrared shielding optical member which has the infrared shielding transparent base material of Example 1- Example 7 is applicable to the window glass for construction materials, the window glass of a car, etc.

  In all of Examples 1 to 7, the thickness of the coating layer is about 10 μm and is 20 μm or less.

  On the other hand, in Comparative Examples 1 to 4 using boride particles having a carbon concentration higher than 0.2% by mass as a raw material, the average dispersed particle diameter is larger than 100 nm in 20 hours of pulverization, and the diffusion transmission profile is maximum The value is also higher than 1.5%. For this reason, there is a problem in applying it to window glass for building materials, window glass for cars, etc., such as blue haze.

Claims (9)

Having a coating layer on at least one surface of the transparent substrate;
The coating layer includes infrared shielding particles and a binder,
The infrared shielding particles have the general formula XB _m (where X is Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sr, and Ca. Infrared which is a boride particle represented by one or more selected metal elements, m is a number indicating the amount of boron in the general formula), and the carbon content is 0.2% by mass or less as measured by a combustion-infrared absorption method Shielding transparent substrate. The infrared shielding transparent substrate according to claim 1, wherein _m in the general formula XBm is 4.0 or more and 6.2 or less. The infrared shielding transparent substrate according to claim 1 or 2, wherein the amount of B ₄ C contained in the boride particles is 1.0 mass% or less.   4. The infrared shielding transparent base material according to claim 1, wherein the boride particles have an average dispersed particle diameter of 1 nm to 100 nm.   The infrared shielding transparent substrate according to any one of claims 1 to 4, wherein the binder includes one or more selected from an ultraviolet curable resin, a thermoplastic resin, a thermosetting resin, and a room temperature curable resin.   The infrared shielding transparent substrate according to claim 1, wherein the coating layer has a thickness of 20 μm or less.   The maximum value of the diffuse transmission profile in a region of a wavelength of 360 nm or more and 500 nm or less is 1.5% or less when the visible light transmittance of the coating layer is set in a range of 45% or more and 55% or less. The infrared shielding transparent base material according to any one of the above.   The infrared shielding transparent substrate according to any one of claims 1 to 7, wherein the transparent substrate is a transparent film substrate or a transparent glass substrate.   The infrared shielding optical member containing the infrared shielding transparent base material as described in any one of Claims 1 thru | or 8.

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