JPH10101340A - Coating liquid for solar shading film and solar shading film using the same - Google Patents

Abstract

(57) [Summary] [Problems] To form a film on a substrate using an inexpensive coating method, control the visible light transmittance, have an efficient solar shading function, and also have an ultraviolet shading function. Shielding film,
And a coating liquid for a solar shading film therefor. SOLUTION: Ruthenium oxide, iridium oxide,
Alternatively, a coating liquid for a solar shading film in which one or two or more of rhodium oxide particles having an average particle diameter of 100 nm or less are dispersed in a dispersion medium. In addition, a coating liquid for a solar shading film in which fine particles having an average particle diameter of 100 nm or less of one or more of ruthenium oxide, iridium oxide, and rhodium oxide are dispersed in a resin binder is applied to a resin substrate. A solar shading film obtained after drying. Furthermore, a multilayer solar shading film in which a resin film is coated on the solar shading film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to vehicles, buildings, offices,
The present invention relates to a coating liquid for a solar shading film that can be used in a wide range for shielding solar heat rays, such as windows of general houses, telephone boxes, show windows, and parasols, and a solar shading film using the same.

[0002]

2. Description of the Related Art Sunlight is broadly divided into three types: near-infrared light (heat ray), visible light and ultraviolet light. A heat ray is a wavelength region that is felt by the human body as heat energy, and causes a rise in indoor temperature in summer. In addition, it has been pointed out that ultraviolet light has an adverse effect on the human body such as skin cancer. Furthermore, for visible light, for example, by controlling the transmittance of the window glass in that region, a privacy protection function can be provided.

Conventionally, noble metals (Au,
Ag, Cu) and metal materials having a large amount of conduction electrons, such as aluminum, have been used. These materials are
In addition to heat rays, it has the property of simultaneously reflecting or absorbing light in the visible light range, and has the disadvantage of reducing visible light transmittance. Therefore, when using these materials for transparent base materials such as building materials, vehicles, telephone boxes, etc., high transmittance in the visible light region is required, so operations such as extremely thin film thickness are required, It has been difficult to provide sufficient heat ray shielding characteristics. In addition, the pure metal material has a problem in terms of mutual diffusion with the base material and stability of the film.

[0004] Indium tin oxide (ITO), aluminum-added zinc oxide (AZO), and the like are known as materials having a visible light transmitting property and a heat ray shielding function. The amount of electrons was smaller than that of metal, and it was difficult to obtain a sufficient heat ray shielding function.

As a method of forming a film using the above-mentioned materials, a sputtering method or a vapor deposition method is used. However, these methods require a large-scale vacuum apparatus, so that productivity and large-area formation are required. There is a problem with the film, and there is a problem that the production cost of the film is high.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, forms a film on a substrate using a very inexpensive coating method, controls the visible light transmittance, and improves the efficiency. An object of the present invention is to provide a solar shading film having a good solar shading function and an ultraviolet shading function, and a coating solution for the solar shading film for producing the same.

[0007]

The present invention for solving the above-mentioned problems of the prior art is characterized in that the material itself has absorption in the ultraviolet region, transparency in the visible region, and freeness. Focusing on ruthenium oxide fine particles or iridium oxide fine particles or rhodium oxide fine particles, which are oxides that retain a large amount of electrons and have strong plasmon reflection,
This shows a solar shading film containing the same, characterized in that one or more of ruthenium oxide, iridium oxide, or rhodium oxide is dispersed in a dispersion medium in fine particles having an average particle diameter of 100 nm or less. It is a coating liquid for a solar shading film.

Further, the solar shading film of the present invention is a solar shading film in which fine particles of one or more of ruthenium oxide, iridium oxide and rhodium oxide having an average particle diameter of 100 nm or less are dispersed in a resin binder. The method is characterized in that the coating liquid for a film is applied to a resin substrate and then dried.

Further, the multilayer solar shading film of the present invention is characterized in that a resin film is further coated on the solar shading film.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Ruthenium oxide fine particles, iridium oxide fine particles, or rhodium oxide fine particles (hereinafter referred to as "oxide fine particles") include ruthenium dioxide (RuO ₂ ), bismuth ruthenate ( Bi ₂
Ru ₂ O ₇ ) lead ruthenate (Pb ₂ Ru ₂ O _6.5 ), rhodium dioxide (RhO ₂ ), iridium oxide (Ir)
O ₂ ), bismuth iridate (Bi ₂ Ir ₂ O ₇ ), lead iridate (Pb ₂ Ir ₂ O _6.5 ) and the like can be mentioned as typical examples.

The above oxide fine particles are all black powders exhibiting metallic electrical conductivity. When dispersed in a thin film as fine particles having a particle diameter of 100 nm or less, visible light transmittance is generated, but near infrared light shielding ability can be sufficiently maintained, and light in the ultraviolet region is absorbed.

The average particle size of the oxide fine particles in the coating solution is 10
It is necessary that the thickness be 0 nm or less. Average particle is 100
When the diameter is larger than nm, the tendency of the fine particles in the dispersion liquid to agglomerate with each other becomes strong, which causes sedimentation of the fine particles in the coating solution. Also, the fine particles exceeding 100 nm or the aggregated coarse particles are caused by the light This is because scattering causes a decrease in visible light transmittance.

The dispersion medium of the oxide fine particles in the coating solution is not particularly limited, and the coating conditions, the chemical resistance of the substrate,
Compatibility with the resin binder, can be selected according to the coating environment, etc., for example, water, methyl alcohol, ethyl alcohol, isopropyl alcohol, isobutyl alcohol, diacetone alcohol, cyclohexane, cyclohexanone, toluene, isophorone, butyl acetate, ethyl Cellosolve, methyl cellosolve, butyl cellosolve,
Cellosolve acetate, methyl cellosolve acetate,
Methyl ethyl ketone, N-methyl-2-pyrrolidinone,
Various types such as N, N-dimethylformamide can be used, and the pH may be adjusted by adding an acid or an alkali as needed.

Further, in order to improve the dispersion stability of the oxide fine particles, various kinds of coupling agents, surfactants and the like can be used. % Or less, preferably 5% by weight or less. The method for dispersing the oxide fine particles may be any method as long as the fine particles are uniformly dispersed in the solution, and examples thereof include a ball mill, a sand mill, and an ultrasonic dispersion method.

The solar shading film of the present invention is a film in which oxide fine particles are deposited at high density on a substrate to form a film. The resin binder contained in the coating solution is solidified after drying, has a role of an adhesive for improving the binding property of the oxide fine particles to the substrate, and further has an effect of improving the hardness of the film. Also,
By further coating a resin as a second layer on the film obtained in this way, the binding force of the film containing the oxide fine particles as a main component to a substrate, and the hardness and weather resistance of the film are further improved. It is possible to do.

In the case where the coating solution does not contain a resin binder, a film obtained by applying the coating solution to a substrate and drying it is as follows:
A film structure in which oxide fine particles are deposited on the substrate is obtained. Although the solar radiation shielding function is exhibited as it is, the resin component in the coating liquid is formed by filling the gap where the oxide fine particles of the first layer are deposited by further applying a coating liquid containing a resin to this film. In addition, the haze of the film is reduced, the light transmittance in the visible light region is improved, and the binding of the oxide fine particles to the substrate is improved.

The coating liquid for coating (hereinafter referred to as "coating liquid") and the resin binder in the coating liquid include:
A liquid containing a resin such as a thermoplastic resin such as an acrylic resin, a thermosetting resin such as an epoxy resin, a vinyl resin, a urethane resin, a silicone resin, an ultraviolet ray, or an electron beam curable resin can be used.

The coating solution and the method of applying the coating solution are not particularly limited, and include a bar coating method, a blade coating method, a spin coating method, a spray coating method, a dip coating method, a screen printing method, a roll coating method and the like. Any method may be used as long as it can apply the liquid evenly and thinly.

The coating liquid of the present invention does not form a desired solar shading film by utilizing the decomposition or chemical reaction of ink components by heat. Therefore, it is possible to form a thin film having stable characteristics and a uniform thickness.

The thickness of the solar shading film of the present invention is determined by required transparency and solar shading ability, and is usually 0.05 μm.
About m to 5 μm is preferable. If the film thickness is less than 0.05 μm, an effective solar shading effect cannot be obtained, and the distribution of fine particles in the film tends to be non-uniform, which is not preferable. It is also possible to produce a thick film, but if the film thickness is 5 μm or more, it is difficult to maintain sufficient transparency, which is not preferable.

Since each of the above oxides is a highly conductive oxide exhibiting metallic conduction, when only these are coated on a substrate, they basically become a highly conductive film. However, the structure of the solar shading film according to the present invention is as follows. By mixing a resin having a high electrical insulating property in the film, each fine particle and its secondary aggregate can be present in the film in an electrically isolated state, resulting in a surface resistance of 1 MΩ / □. The above film can be manufactured. The solar shading film with such high surface resistance enables the use of radio wave communication devices such as mobile phones and radio wave receivers such as radios, televisions, pagers, etc. in the room where the solar shading film is applied, expanding the range of applications. . The oxide fine particles are a material that absorbs in the visible light region, and by reducing the thickness thereof, the transmittance in the visible light region can be improved. The color of each oxide fine particle dispersion film having the visible light transmittance is from bronze color to
Shows a dark green color. This is considered to be a manifestation of multiple effects such as absorption due to electron-to-band transition, particle size distribution and dispersion state of fine particles. For this reason, by coating the substrate with the oxide fine particle dispersion film of the present invention, not only ultraviolet and near-infrared rays are blocked, but also a bronze color
It is also possible to have a very beautiful dark green color tone. Further, when applied to a transparent substrate, it becomes possible to control the visible light transmittance by changing the film thickness and the like, and the application value as a privacy protective film is high.

The coating solution of the present invention may be further added with one or more organic ultraviolet materials such as titanium oxide, zinc oxide and cerium oxide as inorganic ultraviolet shielding materials, and one or more organic ultraviolet materials such as benzophenone and benzotriazole. It is possible to further improve the shielding ability.

The solar shading film of the present invention can be directly applied to various substrates and used as a solar ray filter. In addition, by selecting a solvent and a resin component in the coating solution, the coating can be applied at room temperature after application. After solidification, the function of the solar ray filter can be immediately given to the base material. Further, the film of the present invention can be formed on a thin film, and this film can be directly adhered to a target substrate with an adhesive or the like to be used as a solar ray filter or a privacy protection film.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail based on embodiments. Example 1 Ruthenium oxide (RuO ₂ ) fine particles having an average particle diameter of 30 nm: 15 g, N-methyl-2-pyrrolidone (NMP): 13 g, diacetone alcohol (DA)
A): 14 g, methyl cellosolve: 57.5 g, and titanate-based coupling agent (Preneact KR-44 manufactured by Ajinomoto Co., Inc.): 0.5 g were mixed, and the diameter was 4 mm.
Was mixed with a ball mill for 100 hours using a zirconia ball of No. 1 to prepare 100 g of a mixed solution of ruthenium oxide. This is designated as solution A.

On the other hand, an epoxy resin 50% by weight methyl ethyl ketone solution was prepared as a resin binder solution. This is designated as solution B.

The solution A and the solution B are each diluted with methyl cellosolve to a desired concentration, the solution A and the solution B are mixed and stirred, and the solid content of ruthenium oxide and epoxy resin is 4% by weight of the whole, Ruthenium to epoxy resin weight ratio of 7
5:25. This is designated as liquid C.

The solution C was applied on a 0.1 mm thick PET (polyethylene terephthalate) film using a bar coater. This was placed in a dryer at 100 ° C. and heat-cured for 1 hour, and the solvent was evaporated to obtain a target film.

The surface resistance of the formed film was measured using a surface resistance meter manufactured by Mitsubishi Yuka Corporation. Further, the spectral transmittance of the formed film at 340 to 1800 nm was measured, and JI was measured.
According to SR 3106, the solar radiation transmittance and the visible light transmittance were calculated. The haze value of the film was measured using a haze meter. The spectral transmittance of the sample in the ultraviolet region was measured, and
The UV transmittance was calculated according to 050. Table 1 shows the results. Table 1 also shows the characteristics of the films obtained in Examples 2 to 9 and Comparative Examples 1 and 2.

[0029]

[Table 1]

Example 2 A method similar to that of Example 1 except that the solid content in the liquid C was 1.2% by weight and the weight ratio of ruthenium oxide to epoxy resin was 75:25. The film was produced with. Table 1 shows the results of the same evaluation as in Example 1.

Example 3 A method similar to that of Example 1 except that the solid content concentration in the liquid C was 1.4% by weight and the weight ratio of ruthenium oxide to epoxy resin was 70:30. The film was produced with. Table 1 shows the results of the same evaluation as in Example 1.

Example 4 The concentration of solids in the liquid C was 0.8% by weight, the weight ratio of ruthenium oxide to epoxy resin was 100: 0, and this solution was coated on a 0.1 mm PET film with a bar coater. It was applied using. This is 80
After drying in a drier at 30 ° C. for 30 minutes, solution B diluted with methyl cellosolve to a solid content of 15% by weight is further applied to this substrate in the same manner as described above to form a two-layer film. did. Table 1 shows the results of the same evaluation as in Example 1.

Example 5 An acrylic resin was used in place of the epoxy resin in the liquid B, the solid content concentration in the liquid C was 3.0% by weight, and the weight ratio of ruthenium oxide to the acrylic resin was 85:15. And a heating step at 80 ° C. for 1
A film was produced in the same manner as in Example 1 except that the time was 5 minutes. Table 1 shows the results of the same evaluation as in Example 1.

Example 6 A membrane was prepared in the same manner as in Example 5, except that the solid content in the solution C was adjusted to 4.8% by weight. Table 1 shows the results of the same evaluation as in Example 1.

Example 7: Ruthenium oxide (Ru)
Liquid A was prepared in the same manner as in Example 1, except that iridium oxide (IrO ₂ ) was used instead of the O ₂ ) fine particles and a silane coupling agent was used instead of the titanate coupling agent. 1.3% by weight of solids concentration in liquid C
A film was produced in the same manner as in Example 1 except that the above conditions were satisfied. Table 1 shows the results of the same evaluation as in Example 1.

Example 8: Ruthenium oxide (Ru)
O ₂₎ in place of the fine particles, lead ruthenate (Pb ₂ Ru ₂
O _6.5 ) and a film was prepared in the same manner as in Example 7 except that the weight ratio of lead ruthenate to epoxy resin in the solution C was 80:20. Table 1 shows the results of the same evaluation as in Example 1.
Shown in

Example 9: Ruthenium oxide (Ru)
O ₂ ) fine particles, instead of lead iridate (Pb ₂ Ir)
₂ O _6.5 ) to _reduce the total solid concentration in solution C to 1.2% by weight.
A film was produced in the same manner as in Example 7, except that Table 1 shows the results of the same evaluation as in Example 1.

Comparative Example 1 A film was prepared in the same manner as in Example 1, except that the average particle size of the ruthenium oxide fine particles used was 140 nm. The obtained film with a film had a very high haze value of 45, and became like a cloudy glass. In addition, a large amount of precipitate was generated in the ink, and the desired film and ink could not be obtained.

COMPARATIVE EXAMPLE 2 The solid content concentration in the liquid C was 1% by weight, and the weight ratio between ruthenium oxide and epoxy resin was 8
A film was produced in the same manner as in Comparative Example 1, except that the ratio was set to 0:20. As in Comparative Example 1, the obtained film with a film had a very high haze value of 29 and became like a cloudy glass. In addition, a large amount of precipitate was generated in the ink, and the desired film and ink could not be obtained.

[0040]

As shown in the above embodiments, the solar shading film of the present invention has a high heat-shielding efficiency particularly in the near infrared region (780 to 1400 nm) where the intensity of the solar spectrum is high. Extremely effective. In addition, it absorbs light in the ultraviolet region, which has an adverse effect on the human body, and can control the transmittance in the visible light region, making it a material that can comprehensively control the ultraviolet, visible, and near-infrared light of sunlight. Is wide. In addition, since the surface resistance of the film can be increased to 1 MΩ / □ or more despite the use of highly conductive fine particles, a radio communication device such as a mobile phone, a radio, a television, A radio receiver such as a pager can be used, which is suitable for the current radio situation. Further, as compared with a heat ray shielding film formed by a high-cost physical film formation method, a film can be formed by a simple and inexpensive coating method, and the industrial utility is high in terms of cost and large-area film formation.

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Claims (3)

[Claims] 1. A ruthenium oxide, an iridium oxide,
Alternatively, a coating liquid for a solar shading film in which one or two or more of rhodium oxide particles having an average particle diameter of 100 nm or less are dispersed in a dispersion medium. 2. Ruthenium oxide, iridium oxide,
Alternatively, a solar shading film obtained by applying a solar shading film coating liquid in which one or two or more kinds of rhodium oxide particles having an average particle diameter of 100 nm or less are dispersed in a resin binder to a resin substrate and then drying. 3. A multilayer solar shading film, wherein a resin film is further coated on the solar shading film according to claim 2.