JPH11258417A - Coating liquid for forming heat-ray-shielding film and heat-ray-shielding film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating liquid from which a film having high transmittance and low reflectance in the visible light region and low transmittance and high reflectance in the near infrared region and film conductivity controllable to be about 10<6> Ω/(square) or higher can be formed by a simple coating method without requiring a costly physical film formation method and to provide a heat-ray shielding film produced from the coating liquid. SOLUTION: This coating liquid contains dispersed fine particles of carbides of one or more metals selected from Ti, V, Zr, Hf, Nb, Ta, W, and B with an average particle diameter of 100 nm or smaller and further a fine particle of ruthenium oxide or iridium oxide with an average particle diameter of 100 nm or smaller. This heat ray-shielding film is obtained by applying any of such a coating liquid to a substrate and then drying the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent or transparent glass or plastics or any other heat ray shielding function, such as a window for a vehicle, a building, an office or a general house, a telephone box, a show window, a lighting lamp and the like. The present invention relates to a coating liquid for applying to a translucent substrate to form a heat ray shielding film, and a heat ray shielding film obtained by the application liquid.

[0002]

2. Description of the Related Art Conventionally, as a method of removing or reducing a heat component from an external light source such as sunlight or a light bulb, a heat ray reflecting glass using a material which reflects a visible / infrared wavelength on a glass surface is used. Was being done. As materials for heat ray reflection, metal oxides such as FeO _x , CoO _x , CrO _x , and TiO _x and metal materials having a large amount of free electrons such as Ag, Au, Cu, Ni, and Al are selected. It has been.

However, these materials have the property of simultaneously reflecting or absorbing light in the visible light region in addition to near infrared rays which greatly contribute to the thermal effect, and have a drawback that the visible light transmittance is reduced. Transparent base materials used for building materials, vehicles, telephone boxes, etc., require high transmittance in the visible light region, and when using these materials, the thickness must be extremely thin to increase the visible light transmittance. Must be
Therefore, it has been generally practiced to form an extremely thin film having a thickness of 10 nm using a physical film forming method such as spray baking, a CVD method, or a sputtering method or a vacuum evaporation method.

[0004] These film forming methods require large-scale equipment and vacuum equipment, have problems in productivity and increase in area, and have a high film manufacturing cost.

[0005] Further, when these films are made thinner to increase the transmittance, the heat ray shielding characteristics are degraded. Conversely, when the film thickness is increased to increase the heat ray shielding characteristics, the films become darker. Further, when the heat ray shielding properties of these materials are to be enhanced, the reflectance in the visible light region tends to be increased at the same time, giving a glare-like appearance like a mirror and impairing the aesthetic appearance.

Further, many of these materials have high conductivity of the film. If the conductivity of the film is high, mobile phones and T
V, radio and other radio waves are reflected and become unreceivable,
There were drawbacks such as causing radio interference in the surrounding area.

[0007] In order to improve the above-mentioned drawbacks, the physical properties of the film are such that the reflectance of light in the visible light region is low, the reflectance of light in the near infrared region is high, and the conductivity of the film is low. Generally 1
0 ⁶ Ω / □ has been necessary to form a controllable membrane above. However, conventionally, such a film or a material for forming such a film has not been known.

As a material having a high visible light transmittance and a heat ray shielding function, antimony-containing tin oxide (ATO)
Also, tin-containing indium oxide (ITO) is known.
Although these materials have a relatively low visible light reflectance and do not give a glare-like appearance, the plasma wavelength is relatively long in the near infrared region, and these films have a near-infrared region close to visible light. The reflection and absorption effects were not sufficient. Further, when these films are formed by a physical film forming method, there is a disadvantage that the conductivity of the films is increased and radio waves are reflected.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and has a high transmittance of light in the visible light region, a low reflectance, and a low transmittance of light in the near infrared region. A coating solution that can form a film having high reflectivity and a film conductivity of approximately 10 ⁶ Ω / □ or more by a simple coating method without using an expensive physical film forming method; It is an object to provide a heat ray shielding film used.

[0010]

Means for Solving the Problems In order to achieve the above object, the present inventors have focused on a carbide having a large amount of free electrons as a characteristic of the material itself, and as a result of various studies, have found that this is converted into ultrafine particles. In addition, by obtaining a highly dispersed film, it has a maximum transmittance in the visible light region and a strong plasma reflection in the near infrared region near the visible light region to have a minimum transmittance. After finding the phenomenon, the present invention was completed.

That is, the coating liquid for a heat ray shielding film of the present invention comprises Ti, V, Zr, Hf, Nb, Ta, W, and
Fine particles having an average particle diameter of 100 nm or less made of carbide of one or more metals selected from the group B are dispersed.

Further, another coating liquid for forming a heat ray shielding film according to the present invention may include one or more metals selected from the group consisting of Ti, V, Zr, Hf, Nb, Ta, W, and B. And fine particles of an average particle size of 100 nm or less, and at least one kind of ruthenium oxide particles with an average particle size of 100 nm or less or iridium oxide particles with an average particle size of 100 nm or less.

[0013] In another aspect of the present invention, the coating solution for forming a heat ray shielding film further comprises a metal alkoxide of silicon, zirconium, titanium or aluminum or a partially hydrolyzed polymer of metal alkoxide. Characterized in that it contains one or more of these.

The coating solution for forming a heat ray shielding film having any one of the above constitutions may contain a resin binder.

Further, the heat ray shielding film of the present invention is a fine particle dispersion film obtained by applying any one of the above-mentioned coating solutions for forming a heat ray shielding film to a substrate and then heating the substrate. , Ti, V, Zr, Hf, Nb, Ta, W, and
B is carbide fine particles of one or more kinds of metals in B, and the fine particles are one or more kinds of metal oxides of silicon, zirconium, titanium, and aluminum in a resin binder. It is characterized by being dispersed in a binder of an oxide to be contained.

Further, the heat ray shielding film is further coated with an oxide film containing one or more of metal oxides of silicon, zirconium, titanium and aluminum, or , On the heat ray shielding film,
A multilayer heat ray shielding film may be formed by coating a resin film.

Any one of the above heat ray shielding films has a transmittance of
A maximum value at a wavelength of 400 to 700 nm and a wavelength of 700 to 18
It is characterized in that it has a minimum value at 00 nm, the difference between the maximum value and the minimum value is 15 points or more in percentage, and the surface resistance value is 10 ⁶ Ω / □ or more.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The fine carbide particles used in the present invention include titanium carbide (TiC), zirconium carbide (ZrC), hafnium carbide (HfC), vanadium carbide (VC), niobium carbide (NbC), and tantalum carbide. (T
aC), tungsten carbide (WC), boron carbide (B
₄ C) fine particles such as are mentioned as a representative. In addition, the carbide fine particles used in the present invention are preferably not oxidized on the surface, but are usually slightly oxidized, and the surface is oxidized in the fine particle dispersion step to some extent. Unavoidable. However, even in that case, there is no change in the effectiveness of exhibiting the heat ray shielding effect. In addition, these carbide fine particles can obtain a large heat ray shielding effect as the crystal perfection is high. However, even if such carbide fine particles have a low crystallinity and cause an extremely broad diffraction peak in X-ray diffraction, the inside of the fine particles can be reduced. If the basic bond is composed of the bond between each metal and carbon, a heat ray shielding effect is exhibited.

The fine particles of ruthenium oxide or iridium oxide used in the present invention include ruthenium dioxide (RuO ₂ ) and lead ruthenate (Pb ₂ Ru).
₂ O _6.5 ), bismuth ruthenate (Bi ₂ Ru ₂ O ₇ ),
Iridium dioxide (IrO ₂ ), bismuth iridate (Bi ₂ Ir ₂ O ₇ ), lead iridate (Pb ₂ Ir)
_Fine particles such as ₂ O _6.5 ) are typical examples. These fine particles are stable as oxides, retain a large amount of free electrons, and have an extremely effective heat ray shielding function.

These fine particles of carbide, fine particles of ruthenium oxide and fine particles of iridium oxide are powders colored in gray black, brown black, green black or the like, but have a particle size sufficiently smaller than the wavelength of visible light, and are dispersed in a thin film. In this state, the film has visible light transmittance. However, the infrared light shielding ability can be maintained sufficiently strong.

Although the reason for this is not understood in detail,
Since the amount of free electrons in these fine particles is large and the plasma frequency due to free electron plasmons inside and on the fine particles is just in the vicinity of visible to near infrared, heat rays in this wavelength region are selectively reflected and absorbed. It is thought that. According to experiments, in a film in which these fine particles are sufficiently finely and uniformly dispersed, the transmittance has a maximum value at a wavelength of 400 to 700 nm, a minimum value at a wavelength of 700 to 1800 nm, and a maximum value of the transmittance. The difference between the minimum value and the minimum value is 1
It is observed that more than 5 points. Considering that the visible light wavelength is 380 to 780 nm and that the visibility is a bell-shaped peak with a peak around 550 nm, such a film effectively transmits visible light and effectively reflects other heat rays. It can be understood that it is absorbed.

In the present invention, the average particle size of the carbide fine particles, ruthenium oxide fine particles, and iridium oxide fine particles in the coating solution is preferably 100 nm or less. Particle size 100
When it is larger than nm, the specific transmittance profile as described above, that is, the transmittance is 400 to 700 wavelengths
nm with a maximum value and a wavelength of 700 to 1800 nm
A profile having a minimum value and a difference between the maximum value and the minimum value of 15 points or more in percentage cannot be obtained, and a grayish film having a monotonously reduced transmittance is obtained.

When the particle diameter is larger than 100 nm, the tendency of the fine particles in the dispersion to agglomerate becomes stronger,
It causes sedimentation of fine particles. Further, the fine particles having a size of 100 nm or more or the aggregated coarse particles serve as a light scattering source, causing clouding (haze) in the film and causing a decrease in visible light transmittance. Therefore, the average particle size of the inorganic fine particles needs to be 100 nm or less. The lowest particle size economically available is about 2 nm, but the lower limit is not limited to this.

The dispersion medium of the fine particles in the coating solution is not particularly limited, and can be selected in accordance with the coating conditions and coating environment, the alkoxide in the coating solution, the synthetic resin binder, and the like. Various organic solvents such as ethers, ethers, esters and ketones can be used, and the pH may be adjusted by adding an acid or an alkali as needed. Further, in order to further improve the dispersion stability of the fine particles in the coating liquid, it is possible to add various surfactants, coupling agents and the like. The amount of each addition at that time is 30% by weight or less, preferably 5% by weight or less based on the inorganic fine particles.

When the film is formed by using this coating solution, the conductivity of the film is formed along the conductive path passing through the contact portion of the fine particles. Therefore, for example, the amount of the surfactant or the coupling agent is adjusted. , The conductive path can be partially cut, and the conductivity of the film can be easily reduced to a surface resistance value of 10 ⁶ Ω / □ or more. The conductivity can also be controlled by adjusting the content of a metal alkoxide of silicon, zirconium, titanium, or aluminum, or a partially hydrolyzed polymer of these metals, or a synthetic resin binder.

The method for dispersing the fine particles can be arbitrarily selected as long as the fine particles are uniformly dispersed in the solution. Examples of the method include a bead mill, a ball mill, a sand mill, and an ultrasonic dispersion method. .

The heat ray shielding film in the present invention is a film in which the above-mentioned fine particles are deposited at a high density on a substrate to form a film, and a metal alkoxide of silicon, zirconium, titanium or aluminum contained in a coating solution or The metal partially hydrolyzed polymer or synthetic resin binder is applied,
After curing, there is an effect of improving the binding property of the fine particles to the base material and further improving the hardness of the film. Further, a film containing a metal alkoxide such as silicon, zirconium, titanium, and aluminum or a hydrolyzed polymer of these metal alkoxides or a synthetic resin is further applied as a second layer on the film thus obtained. In addition, it is possible to further improve the binding force of the film containing fine particles as a main component to the substrate, and the hardness and weather resistance of the film.

Silicon, zirconium, titanium,
When a metal alkoxide of aluminum, or a hydrolyzed polymer of these metals, or a synthetic resin binder is not contained, a film obtained after applying this coating solution to a substrate has a film structure in which only the fine particles are deposited on the substrate. Become. Although it shows a heat ray shielding effect as it is, a coating solution containing a metal alkoxide of silicon, zirconium, titanium, aluminum, or a hydrolyzed polymer of these metals, or a synthetic resin binder is further applied to the film as described above. By forming a multi-layered film, the coating solution components are formed to fill the gaps where the fine particles of the first layer are deposited, so that the haze of the film is reduced, the visible light transmittance is improved, and the base of the fine particles is reduced. The binding to the material is improved.

As a method of bonding a film containing the above fine particles as a main component with a film made of a metal alkoxide of silicon, zirconium, titanium, or aluminum, or a hydrolyzed polymer of these metals, a sputtering method and a vapor deposition method are also available. Although it is possible, the coating method is effective because of advantages such as easiness of the film forming process and low cost. The coating liquid for coating contains one or more kinds of metal alkoxides of silicon, zirconium, titanium, and aluminum, or a hydrolyzed polymer of these metals in water or alcohol, and the liquid containing the alkoxide is obtained after heating. It is preferably 40% by weight or less in the total solution in terms of oxides to be obtained. If necessary, the pH can be adjusted by adding an acid or an alkali. Such a liquid is further applied as a second layer on a film containing the fine particles as a main component, and heated, so that silicon, zirconium, titanium,
An oxide film of aluminum or the like can be easily formed.

The method of applying the coating liquid and the coating liquid for forming a coating film is not particularly limited, and treatment liquids such as spin coating, spray coating, dip coating, screen printing, roll coating, and flow coating can be used. Any method can be used as appropriate as long as it is a method that can be applied uniformly and thinly.

The substrate heating temperature after application of the coating solution containing the metal alkoxide and its hydrolyzed polymer is 100 ° C.
If it is less than 1, the polymerization reaction of the alkoxide or its hydrolyzed polymer contained in the coating film often remains uncompleted, and water and organic solvents remain in the film, reducing the visible light transmittance of the film after heating. Therefore, the heating is preferably carried out at a temperature of 100 ° C. or higher, more preferably at a temperature higher than the boiling point of the solvent in the coating solution.

When a synthetic resin binder is used, it may be cured according to the respective curing method. For example, an ultraviolet curable resin may be appropriately irradiated with ultraviolet rays, and a room temperature curable resin may be left as it is after application. Since it is sufficient to apply it, it can be applied to an existing window glass or the like on site, and the versatility is expanded.

An organosilazane solution may be used as a binder component used in the coating solution of the present invention or as a coating solution for overcoating. As organosizaran solutions, those having a polymerization curing temperature of 100 ° C. or less due to modification of a side chain group or addition of an oxidation catalyst are commercially available. By using these, the film forming temperature can be considerably lowered. As the room temperature curable binder, a commercially available silicate-based binder can be used. In both cases, an inorganic film of SiO ₂ is formed after curing, and is superior to a resin film in weather resistance and film strength.

Since the film of the present invention is a film in which the above-mentioned ultrafine particles are dispersed, a film having a mirror-like surface in which crystals are densely filled like a thin oxide film produced by a physical film-forming method. The reflection in the visible light region is less than that of the above, and it is possible to avoid giving a glare-like appearance. On the other hand, since the plasma frequency is in the visible to near-infrared region as described above, the accompanying plasma reflection increases in the near-infrared region,
It has very favorable characteristics. When it is desired to further suppress the reflection in the visible light region, a film having a low refractive index such as SiO ₂ or MgF can be easily formed on the fine particle dispersion film to have a luminous reflectance of 1% or less. Multilayer films can be manufactured.

The coating liquid of the present invention may further contain ultrafine particles such as ATO, ITO and aluminum-added zinc oxide in order to improve the transmittance. As the amount of these transparent ultrafine particles increases, the absorption in the near infrared region close to visible light increases, so that a heat ray shielding film having high visible light transmittance can be obtained. And ATO and I
It is also possible to add the coating liquid of the present invention to a liquid in which ultrafine particles such as TO or aluminum-added zinc oxide are dispersed, to color the film and at the same time assist its heat ray shielding effect. In this case, since the heat ray shielding effect can be assisted with a very small addition amount to ITO or the like as a main component, the required amount of ITO can be greatly reduced, and there is an advantage that the cost of the liquid can be reduced.

The coating solution of the present invention also contains inorganic titanium oxide, zinc oxide, and inorganic oxide in order to improve the function of shielding ultraviolet rays harmful to the human body at the same time as the ability to shield infrared rays when the coating film is formed. Fine particles such as cerium and one or more kinds of organic benzophenone and benzotriazole can be added.

The coating liquid according to the present invention is a dispersion in which the above-mentioned inorganic fine particles are dispersed, and does not form a target heat ray shielding film by utilizing decomposition or a chemical reaction of coating components due to heat during baking. A permeable film having a stable and uniform film thickness can be formed.

The fine particle-dispersed film of the present invention is a film in which fine particles are deposited at a high density on a substrate to form a film, and a metal alkoxide of silicon, zirconium, titanium, or aluminum contained in a coating solution or a hydrate thereof. The decomposed polymer or the synthetic resin binder has an effect of improving the binding property of the fine particles to the substrate after the coating film is cured, and further improving the strength of the film.

As described above, according to the present invention, it is possible to produce a film having a heat ray shielding effect by appropriately mixing the above-mentioned inorganic fine particles. Weather resistance is very high compared to materials,
For example, even if it is used in the area where sunlight (ultraviolet rays) hits,
Deterioration of color and functions hardly occurs.

[0040]

EXAMPLES Examples of the present invention will be described below together with comparative examples.

Example 1 TaC having an average particle size of 72 nm
8 g of fine particles, 80 g of diacetone alcohol (DAA),
An appropriate amount of water and a dispersant were mixed, and the mixture was ball-milled using zirconia balls having a diameter of 4 mm for 100 hours to prepare 100 g of a TaC dispersion. This is designated as solution A. 50 g of an ethyl silicate solution prepared from 6 g of ethyl silicate 40 (manufactured by Tama Chemical Industry Co., Ltd.) having an average degree of polymerization of 4 to pentamer, 31 g of ethanol, 8 g of 5% aqueous hydrochloric acid, and 5 g of water
Well mixed with 800 g of water and 300 g of ethanol
The mixture was stirred to prepare 1150 g of an ethyl silicate mixed solution. This is designated as solution B.

The solution A and the solution B were mixed at a TaC concentration of 1.0%
The mixture was mixed and stirred at a ratio such that the aC / SiO ₂ ratio was 4: 1 to prepare a coating solution. This is designated as liquid C. Rotate 15 g of this solution at 145 rpm 200 × 200 × 3m
m from a beaker onto a soda lime glass substrate,
After shaking for 3 minutes, the rotation was stopped. This one
The resultant was heated in an electric furnace at 80 ° C. for 30 minutes to obtain a target film.

The spectral characteristics of the formed film were measured using a spectrophotometer manufactured by Hitachi, Ltd. FIG. 1 shows a transmission profile of the film of this example using TaC fine particles. The maximum value of the transmittance is 497 nm and the minimum value is 864 nm, the difference between the maximum value and the minimum value is sufficiently large as 27 points, and JI
Based on SR-3106, a visible light transmittance of 53.5% was obtained as a net value of the film.

The transmission color of the film according to this example was a beautiful blue-violet color. Further, the visible light reflectance was as low as 4.6%, and no glare was observed on the film surface as in a commercially available heat ray reflective glass.

Further, the surface resistance value of this film was measured using a surface resistance meter manufactured by Mitsubishi Chemical Corporation and found to be 2.7 × 10 ¹³ Ω /.
□ was obtained, and it was found that there was no problem in radio wave transmission because the film resistance was sufficiently high.

(Comparative Example 1) A commercially available heat-reflective bronze glass produced by a physical film forming method which is more expensive than the coating method was measured for a spectral transmittance of 340 to 1800 nm, and was visible according to JIS-R-3106. The light transmittance was determined to be 38.8%. Further, the visible light reflectance was as high as 34.2%, and the appearance was a mirror-like appearance. The surface resistance of the film surface is 83Ω /
It is clear that there is a problem in radio wave transmission and reflection, as low as □.

(Example 2) After spin-coating the liquid C prepared in Example 1 as the first layer of the sheet glass, the rotation was continued for 3 minutes, and then the liquid B was 0.9% in terms of SiO ₂ solid content. Then, 15 g of a silicate solution diluted with ethanol was dropped from a beaker onto a plate glass, and the rotation was further continued for 3 minutes. Then, the rotation was stopped. The glass substrate of the two-layer film coated in this manner is placed in an electric furnace at 180 ° C.
After heating for 0 minutes, the desired two-layer film was obtained.

The spectral characteristics of the formed film were evaluated in the same manner as in Example 1. Although the visible light transmittance increased to 57.6%, the visible light reflectance became 2.8%, and the reflected light was further suppressed. Further, when a black tape was stuck on the back surface and the measurement was performed without reflection from the back surface, the visible light reflectance was 0.6%, and the appearance was close to that of non-reflective glass. The positions of the maximum value and the minimum value of the transmittance of this film are almost the same as those of the single-layer film in Example 1, and it is apparent that the film has the same heat ray shielding effect.

In the films formed in Examples 3 to 13 and Comparative Examples 2 to 3 below, the visible light transmittance, the maximum and minimum values of the transmittance, and the surface resistance were the same as those described in Example 1. Table 1 shows the results of Examples 1 and 2
It was shown to.

Example 3 TaC having an average particle size of 72 nm
8 g of the fine particles, 80 g of isophorone, water and an appropriate amount of a dispersant were mixed, and the mixture was ball-milled using zirconia balls for 100 hours to prepare 100 g of a TaC isophorone dispersion. This is designated as solution D. As a binder, 50% by weight of an epoxy resin was dissolved in isophorone to prepare an epoxy resin binder solution. This is designated as solution E. The solution D, the solution E and the ethanol were mixed and stirred vigorously so that the solid content of TaC and the epoxy resin was 1.4% by weight and the weight ratio of TaC to the epoxy resin was 70:30 and applied. A liquid was prepared, and a coating liquid was prepared in the same manner as in Example 1.
The film was formed and heated to obtain a film.

(Example 4) As a binder, a cold-setting silicate liquid X-40-9740 manufactured by Shin-Etsu Silicone Co., Ltd.
Was used in place of the B solution to prepare a coating solution in the same manner as in Example 1, and formed into a film. However, without heating, 2
A film that was dried at room temperature of 5 ° C. for 2 days was evaluated.

Example 5 A low-temperature-curable polyperhydrosilazane solution manufactured by NE Chemcat Co., Ltd. was used as a binder in place of the solution E, and the TaC shown in Example 3 was used.
The isophorone dispersion (D solution) and xylene were mixed and stirred to obtain a TaC concentration of 1.0% and a TaC / SiO ₂ ratio of 4:
This was used as a coating liquid so as to be 1. Using this, a film was formed in the same manner as in Example 1, and heated in an electric furnace at 80 ° C. to obtain a film.

Example 6 In the preparation of solution A, TaC
Was used in the same manner as in Example 1 except that WC fine particles having an average particle size of 81 nm were used, and a coating film was formed and heated to obtain a target film.

Example 7 In the preparation of solution A, TaC
Was used in the same manner as in Example 1 except that TiC fine particles having an average particle diameter of 64 nm were used in place of the above, and a coating film was prepared and heated to obtain a target film.

Example 8 In the preparation of solution A, TaC
Was used in the same manner as in Example 1 except that ZrC fine particles having an average particle size of 53 nm were used in place of the above, and a coating film was prepared and heated to obtain a target film.

Example 9 In the preparation of solution A, TaC
Was used in the same manner as in Example 1 except that HfC fine particles having an average particle size of 70 nm were used in place of the above, and a coating film was prepared and heated to obtain a target film.

Example 10 In the preparation of solution A, Ta was used.
A coating solution was prepared in exactly the same manner as in Example 1 except that NbC fine particles having an average particle size of 82 nm were used instead of C, and this was formed and heated to obtain a target film.

Example 11 In the preparation of solution A, Ta was used.
A coating solution was prepared in exactly the same manner as in Example 1 except that VC fine particles having an average particle size of 54 nm were used instead of C, and a coating film was formed and heated to obtain a target film.

(Example 12) 15 g of ruthenium oxide (RuO ₂ ) fine particles having an average particle diameter of 30 nm, N-methyl-2
-Mix 23 g of pyrrolidone (NMP), 57 g of diacetone alcohol (DAA), water and an appropriate amount of dispersant,
Using a zirconia ball having a diameter of 100 mm, ball mill mixing was carried out for 100 hours to prepare 100 g of a RuO ₂ dispersion. This R
In the uO ₂ dispersion, a RuO ₂ concentration of 1%, RuO ₂ : SiO ₂
= 4: 1, and the silicate liquid of the liquid B was mixed and stirred to obtain a RuO ₂ dispersed silicate liquid. This is designated as solution F. The solution A was mixed with the solution F so that the weight ratio of RuO ₂ : TaC was 1.0: 1.0, and the mixture was sufficiently stirred to prepare a coating solution. Using this coating solution, a film was formed and heated in exactly the same manner as in Example 1 to obtain a target film.

Example 13 Ir having an average particle size of 28 nm
A mixed dispersion silicate coating liquid of IrO ₂ : TaC = 1: 1 was prepared in the same manner as in Example 11 except that O ₂ fine particles were used, and this was formed and heated to obtain a target film. .

In the above Examples 1 to 13, for all the films, the transmittance maximum is between 400 and 700 nm, the minimum value is between 700 and 1800 nm, and the difference between the maximum value and the minimum value is It was observed that the percentage was 15 points or more, and it was confirmed that these films were useful as heat ray shielding films. In addition, all the films have a reflectance of 8% or less in the visible light region, no glare in a mirror shape, and a surface resistance value of 6 × 10 ¹¹ Ω / □ or more, so that there is no problem in radio wave transmission. Was confirmed.

Comparative Example 2 Ta having an average particle size of 157 nm
Except for using C, a TaC-dispersed silicate coating solution was prepared in exactly the same manner as in Example 1, and this was formed and heated to obtain a target film. However, since this film has too large a particle diameter, the film has a large haze (haze value of 23%), lacks transparency, becomes slightly greenish gray, and has a small difference of 8% between the maximum value and the minimum value. Therefore, it was judged that it was difficult to practically use as a heat ray shielding film.

Comparative Example 3 ITO having an average particle size of 22 nm
Except for using ultrafine particles, I
A TO-dispersed silicate coating solution was prepared, formed into a film, and heated to obtain a target film. However, this film has a transmittance of 90% or more from the visible light region to the infrared region of 1500 nm.
%) Cannot be used.

[0064]

[Table 1]

[0065]

As shown in the above embodiments, according to the present invention, the transmittance of light in the visible light region is high and the reflectance is low, and the transmittance of light in the near infrared region is low and the reflection is low. A coating solution that can form a film having a high rate and a film conductivity of approximately 10 ⁶ Ω / □ or more by a simple coating method without using a high-cost physical film forming method; A heat ray shielding film could be provided.
The film of the present invention is a heat ray shielding film which has less glare on the surface and is excellent in radio wave permeability as compared with the conventional film. The use of the coating liquid of the present invention has high industrial utility in terms of cost and large-area film.

[Brief description of the drawings]

FIG. 1 is a graph showing transmittance of Example 1 and Comparative Example 2 of the present invention.

Claims (9)

[Claims] 1. Ti, V, Zr, Hf, Nb, Ta,
A coating liquid for forming a heat ray shielding film, in which fine particles having an average particle diameter of 100 nm or less made of a carbide of one or more metals selected from the group consisting of W and B are dispersed. 2. Ti, V, Zr, Hf, Nb, Ta,
W and a fine particle having an average particle diameter of 100 nm or less made of a carbide of one or more metals selected from the group of B and ruthenium oxide fine particles having an average particle diameter of 100 nm or less, or an average particle diameter of 100 nm or less A coating solution for forming a heat ray shielding film, comprising at least one of iridium oxide fine particles. 3. The coating solution for forming a heat ray shielding film according to claim 1, further comprising a metal alkoxide of silicon, zirconium, titanium, or aluminum, or a partial hydrolysis polymerization of a metal alkoxide. A coating liquid for forming a heat ray shielding film, which contains one or more of the above-mentioned materials. 4. The coating solution for forming a heat ray shielding film according to claim 1, further comprising a resin binder. 5. A fine particle dispersed film obtained by applying the coating solution for forming a heat ray shielding film according to any one of claims 1 to 4 to a substrate, followed by heating. , T
i, V, Zr, Hf, Nb, Ta, W, and B are carbide fine particles of one or more of metals.
A heat ray shielding film in which the fine particles are dispersed in a resin binder or a binder of an oxide containing one or more of metal oxides of silicon, zirconium, titanium, and aluminum. 6. A heat ray shielding film obtained by applying the coating solution for forming a heat ray shielding film according to any one of claims 1 to 4 to a substrate and then heating, further comprising silicon, zirconium, titanium, And one of the metal oxides of aluminum
A multilayer heat ray shielding film coated with an oxide film containing one or more species. 7. A resin film is further coated on the heat ray shielding film obtained by applying the heat ray shielding film forming coating liquid according to any one of claims 1 to 4 to a substrate and heating the same. Multilayer heat ray shielding film. 8. The transmittance has a maximum value at a wavelength of 400 to 700 nm, a minimum value at a wavelength of 700 to 1800 nm, and a difference between the maximum value and the minimum value is 15 points or more in percentage. The heat ray shielding film according to claim 7. 9. The heat ray shielding film according to claim 5, which has a surface resistance value of 10 ⁶ Ω / □ or more.