JPH06144874A - Heat ray reflective film and its production - Google Patents

Abstract

PURPOSE:To obtain a heat ray reflective film with radio wave transmissivity by coating a base with a liquid consisting mainly of electrically conductive oxide superfine particles, ruthenium oxide and specific metal oxide(s) followed by heating. CONSTITUTION:A coating liquid consisting mainly of (A) electrically conductive oxide superfine particles, (B) ruthenium oxide and (C) at least one kind of metal oxide selected from silicon oxide, titanium dioxide, zirconium oxide and aluminum oxide, is applied on a base followed by heating to obtain the objective heat ray reflective film. With this method, the final film has high surface resistivity, thereby being furnished with radio wave transmissivity. Therefore, decline in the advantages of radio wave receivers (e.g. antennas) due to the influence of conventional heat ray reflective films can be prevented, and incidence of heat rays into rooms can effectively be reduced without hampering the indoor use of communication equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat ray reflective film having a radio wave transmitting property which can be used for automobile glass, building glass and the like.

[0002]

2. Description of the Related Art Conventionally, a heat ray reflective film has been obtained by coating a relatively highly conductive substance such as titanium nitride, silver or aluminum by a dry method such as vapor deposition or sputtering. However, the heat ray reflective film coated by these methods has a high electric conductivity on the surface and has a high electromagnetic wave shielding property due to its nature, and it cannot be used for indoor antennas, glass print antennas, and mobile phones because it cannot transmit radio waves. There was a flaw.

Further, when titanium nitride, silver, or the like is coated, the reflectance in the visible light region is increased, and the visible light transmittance is lowered, and there is a problem that it cannot be used as it is for glass for automobiles. In practice, an antireflection film was applied and used.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a heat ray reflective film having radio wave transmission performance, and a method for manufacturing the same. .

[0005]

That is, the present invention provides ultrafine particles of a conductive oxide, ruthenium oxide, and at least one metal oxide selected from silicon oxide, titanium oxide, zirconium oxide, and aluminum oxide. And a heat ray reflective film having a surface resistance of 20 KΩ / □ or more, ultrafine particles of a conductive oxide, a ruthenium compound, and silicon. A method for producing a heat ray reflective film, which comprises producing a heat ray reflective film by applying a coating liquid containing at least one selected from a compound, a titanium compound, a zirconium compound and an aluminum compound as a main component, and then heating. Is provided.

In the present invention, in order to prevent the heat ray reflection film from blocking the radio waves entering the room or the radio waves emitted from the communication equipment in the room, the heat ray reflection film is 20 KΩ / □.
Above, it is necessary to have a surface resistance value of preferably 1 MΩ / □ or more. The transmitted and received radio waves are FM, AM, T
The required lower limit of the surface resistance value of the heat ray reflective film is slightly different depending on the purpose such as V, telephone, etc., but if it is 1 MΩ / □ or more, any of these purposes can be sufficiently satisfied.

The heat ray-reflecting film in the present invention contains ultrafine particles of a conductive oxide in the film in order to eliminate the electromagnetic wave shielding property of the conventional heat ray reflecting film of the Drude Mirror type in which the heat ray reflecting performance is expressed by the conductive thin film. It is characterized in that the highly dispersed particles limit the contact between the conductive particles, thereby increasing the surface resistance.

As the ultrafine particles of the conductive oxide in the present invention, antimony-containing tin oxide (ATO), tin-containing indium oxide (ITO) and the like can be used, but it is considered from the viewpoint of economical efficiency, chemical durability and reproducibility. Thus, tin oxide containing antimony can be used relatively favorably.

The dispersion medium and dispersion method of the ultrafine particles of the conductive oxide are not particularly limited, and various kinds can be used. For example, adding conductive oxide ultrafine particles to an organic solvent such as water or alcohol and adding acid or alkali to adjust the pH
After being adjusted, it can be obtained by dispersing with a commercially available pulverizer such as a colloid mill, a ball mill, a sand mill, a homomixer, or an ultrasonic disperser.

The average particle diameter of the conductive oxide ultrafine particles in the dispersion is preferably 100 nm or less. It is preferably 50 nm or less, particularly preferably 20 nm or less. If particles having a particle size of more than 100 nm are used, the transparency of the coating may be impaired and the strength of the coating may be adversely affected. Further, this dispersion can be used after being arbitrarily diluted with alcohol, water or the like.

In the present invention, ruthenium oxide is a conductor itself, but since it has a very strong absorption in the visible light region to the near infrared region, it does not affect the surface resistance value. Addition of a very small amount greatly contributes to the reduction of solar radiation transmittance (JIS-R3106).

It is important to use a ruthenium salt complexed with a chelate ligand such as β-diketone as the ruthenium compound in the coating solution in the present invention. When non-chelate-stabilized ruthenium compounds are used, these inorganic ruthenium compounds are easily decomposed and volatilized by heating, so the amount of ruthenium after heating becomes significantly lower than the charged amount, and the desired transmittance reduction effect. And the reproducibility of the effect becomes poor. Ruthenium salts to be used include ruthenium chloride and ruthenium nitrate, but ruthenium chloride can be used relatively favorably in consideration of economical efficiency and availability.

The chelate complex of a ruthenium compound can be easily obtained by reacting a ruthenium salt with an organic compound serving as a ligand. This reaction may be carried out without a solvent as long as the organic ligand is a liquid (such as acetylacetone), or may be carried out in an organic solvent which is a solvent for the product. When the reaction is difficult to proceed, the reaction can be promoted by heating.

The number of ligands (L) in the ruthenium chelate complex is preferably 1 to 3 in terms of L / Ru molar ratio. When the amount of the ligand is less than this, the ruthenium compound is liable to volatilize as described above, and when the amount of the ligand is more than that, it cannot be reacted with the ruthenium and is wasted.

The coating liquid of the present invention comprises a dispersion liquid of the above-mentioned ultrafine particles of the conductive oxide, a ruthenium chelate compound, and at least one selected from silicon compounds, titanium compounds, zirconium compounds and aluminum compounds as binder components. It is obtained by mixing with a solution containing seeds and diluting to a desired concentration with an organic solvent such as alcohol.

Specifically, Si (OR) _m R _n , Ti
(OR) _m L _n , Zr (OR) _m L _n Al (OR) _u L _v
(However, m + n = 4, m = 1 to 4, n = 0 to 3, u
+ V = 3, u = 1-3, v = 0-3, R = C ₁ -C ₄ alkyl group, L = chelate ligand such as β-diketone,
At least one kind of ligand selected from acylate ligands such as stearic acid), or a solution containing at least one kind of these polymers or a partial hydrolyzate thereof, and a chelate ligand and a complex. It is preferable to add the formed solution containing the ruthenium compound to the ultrafine particle dispersion liquid of the conductive oxide.

These metal-organic compounds not only act as a binder, but also bind to the hydroxyl groups on the surface of the oxide particles in the coating solution to coat the oxide particles, so that the oxide particles are dispersed in the solution. It also increases the resistance and effectively works to increase the resistance when it becomes a film.

When antimony-containing tin oxide is used as the conductive oxide ultrafine particles, a preferable film for forming a film having a surface resistance of 20 KΩ / □ or more to have radio wave transmission performance and heat ray reflection performance. As the composition ratio,
ATO: RuO ₂ : MO _x = 5 in terms of oxide (% by weight)
0 to 90: 3 to 10:10 to 47 (MO _x is SiO ₂ T)
The total of iO ₂ , ZrO ₂ , and Al ₂ O ₃ is shown. ). If the conductive particles are less than this composition ratio, effective heat ray reflection performance cannot be provided, and if the conductive particles are more than this composition ratio, the film strength will be reduced, such being undesirable. Further, if the amount of ruthenium oxide is less than this, the absorption of ruthenium cannot be contributed to the reduction of the solar radiation transmittance, and if it is more than this, the surface resistance value and the film strength may be reduced.

In the coating liquid for forming the radio wave transmission heat ray reflective film, the total solid content is preferably 1 to 30% by weight based on the solvent.

As the base glass in the present invention, ordinary plate glass or float plate glass made of soda lime silicate glass, which is usually used as glass for automobiles and construction, can be used. Absorption glass can also be used.

In the present invention, a coating liquid containing a metal organic compound as a binder component is applied to a dispersion liquid of the above-mentioned ultrafine particles of a conductive oxide, and then heated to heat ray reflection having a radio wave transmitting performance. Form a film. The method of coating the substrate is not particularly limited, and a spray method, a dip method, a roll coating method, a meniscus coating method, a spin coating method, a screen printing method, a flexo printing method, etc. can be used.

The thickness of the heat ray reflective film is from 500Å to 1
μm is preferable, and if it is less than this range, the heat ray reflection performance is inferior, and if it is more than 100 μm, the visible light transmittance of the coating decreases and the transparency is impaired.

[0023]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.
In the following examples and comparative examples, the evaluation methods of the obtained films are as follows.

1) Surface resistance value The surface resistance value of the film surface was measured with a Hiresta resistance measuring instrument (manufactured by Mitsubishi Yuka). 2) Radio wave transmission performance The attenuation factor due to the film in the frequency band of 45 MHz to 1 GHz was measured using a network analyzer (manufactured by Hewlett Packard).

3) Heat ray shielding performance: 340-1800n by spectrophotometer (manufactured by Hitachi Ltd.)
The transmittance of m is measured, the solar radiation transmittance (T _E ) and the visible light transmittance (T _V ) are calculated according to JIS-R3106, and the difference in the transmittance with the base glass (ΔT _E , ΔT _V ), and The ratio (ΔT _E / ΔT _V ) was evaluated.

[Example 1] Tin oxide ultrafine particles containing 9 mol% of Sb (hereinafter referred to as ATO; the same applies hereinafter; average particle size: 10 n)
m) 30 g was added to 70 g of KOH aqueous solution, stirred and dispersed in a sand mill for 4 hours, then deflocculated by heating at 90 ° C. for 1 hour, and after dilution, ion-exchanged was concentrated to a solid content of 20% by weight (solution A). . Acetylacetone was added to a ruthenium chloride crystal (ruthenium content: 38%) in an amount of twice the molar amount of ruthenium, and the mixture was heated at 90 ° C. for 1 hour to obtain a ruthenium chelate complex (solution B).

Ethyl silicate polymer (manufactured by Tama Chemical Industry,
Trade name: Silicate 40) 10 parts by weight of ethanol (61
(Parts by weight), H ₂ O (9 parts by weight), and HCl (0.02 parts by weight) were added for hydrolysis (solution C). A liquid, B liquid,
Liquid C is ATO: RuO ₂ : SiO ₂ = 60: 7: 33
The mixture was mixed so as to have a (weight ratio), and diluted with ethanol to a total solid content of oxides of 5% by weight to obtain a coating liquid.

This coating solution was applied to a float glass plate having a thickness of 2 mm using a spin coater at 500 rpm and 3
After applying for 0 seconds, it is dried in a dryer at 180 ℃ for 10 minutes, and
A coat film was obtained by baking in an electric furnace at 00 ° C for 30 minutes.
The thickness of the obtained coating film is 2200Å and the surface resistance value is 4
MΩ / □, ΔT _E = 22%, ΔT _V = 11% (ΔT _E / ΔT _V = 2.0). In addition, the radio wave permeability is 4
When the attenuation rate at 5 MHz to 1 GHz was measured, it was 0 dB over the entire band.

Examples 2 to 5 Solution A was concentrated to a solid content of 40% by an ultrafiltration device (solution D). Zirconium acetylacetonate butoxide _{(Zr (C 5 H 7 O} 2)
_In an ethanol solution of ₂ (OC ₄ H ₉ ) ₂ , H ₂ O was added to Zr in a 16 mol ratio, and HCl (36.5%) was added to ZrO ₂
5% by weight was added to prepare a solution of 10% by weight in terms of ZrO ₂ (solution E).

Liquids B, C, and D shown in Example 1,
A liquid E was mixed with ATO: RuO ₂ ZrO ₂ : SiO ₂ so as to have a composition shown in Table 1 and diluted with isopropanol to a solid content of 10% by weight to obtain a coating liquid. Using the obtained coating liquid, FIG.
20 cm on a float glass plate with a thickness of 4 mm with one side masked by a dip coating device as shown in
The coating was pulled up at a speed of / min, dried in a dryer at 150 ° C. for 5 minutes, and then baked at 600 ° C. for 5 minutes. The results are shown in Table 2.

[0031]

[Table 1]

Example 6 Titanium acetylacetone isopropoxide (Ti (C ₅ H ₇ O ₂ ) ₂ (OC ₃ H
₇ ) ₂ and aluminum ethyl acetoacetate diisopropoxide Al (C ₆ H ₉ O ₃ ) (OC ₃ H ₇ ) ₂
After mixing so that i / Al = 1/4 (molar ratio) and diluting with ethanol, H ₂ O was converted to Ti + Al in an 8 molar ratio, and HCl (36.5%) was converted to TiO ₂ + Al ₂ O ₃ . On the other hand, 20% by weight was added to obtain a solution having a solid content of oxide of 10% by weight (F liquid). The same procedure as in Example 2 was performed except that the F liquid was used instead of the E liquid shown in the 2nd embodiment.

The coating film thus obtained had a thickness of 2000Å, a surface resistance of 2 MΩ / □, a heat ray shielding performance of ΔT _E = 25%,
ΔT _V = 12% (ΔT _E / ΔT _V = 2.1).
Regarding the radio wave permeability, the attenuation rate was 0 dB over the entire measured band of 45 MHz to 1 GHz (see Table 2).

Comparative Example 1 TiN is formed by reactive sputtering using a titanium target in a nitrogen / Ar atmosphere.
A film was formed. The thickness of the obtained film is 200Å, the surface resistance is 500Ω / □, the heat ray shielding performance is ΔT _E = 14%, ΔT
_V = 13% (ΔT _E / ΔT _V = 1.1). Radio wave permeability is 80MHz (FM radio wave band), 220MH
The attenuation rates at z (VHF TV wave band), 620 MHz (UHF TV wave band) and 900 MHz (cell phone band) were measured to be -0.5 dB and -1.0 d, respectively.
B, -2.5 dB, -4.0 dB (see Table 2).

[Comparative Example 2] A solution prepared by dissolving ruthenium chloride in ethanol instead of the solution B as a ruthenium source in the coating solution shown in Example 2 (ruthenium content: 10).
%) Was performed in the same manner as in Example 2. The obtained coating film has uneven visible light transmittance so that it can be visually discerned, the film thickness is 2000Å, and the surface resistance is 25M.
Ω / □, heat ray shielding performance ΔT _E = 5-8%, ΔT _V = 3
Was ˜5% (ΔT _E / ΔT _V = 1.6 to 1.7)
(See Table 2).

[0036]

[Table 2]

As is clear from the above test results, the heat ray reflective film according to the present invention can effectively shield heat rays without lowering the surface resistance value. Further, since the visible light transmittance does not decrease as compared with the solar radiation transmittance, it can be applied to a portion where the visible light transmittance is desired to be secured (for example, window glass for an automobile).

[0038]

As described above, according to the present invention, it is possible to form a heat ray reflective film having a high surface resistance, so that radio wave transmission characteristics can be provided. Therefore, it is possible to prevent a decrease in the gain of the radio wave receiver (antenna, etc.) due to the influence of the heat ray reflective film, and to effectively reduce the incidence of heat rays into the room without hindering the use of indoor communication equipment. You can

[Brief description of drawings]

FIG. 1 is a dip coating apparatus used in Examples 2 to 5.

[Explanation of symbols]

 1: Glass substrate 2: Liquid reservoir 3: Coating liquid 4: Hood 5: Pulley

Claims (6)

[Claims] 1. Main components are ultrafine particles of a conductive oxide, ruthenium oxide, and at least one metal oxide selected from silicon oxide, titanium oxide, zirconium oxide, and aluminum oxide. A heat ray reflective film having a surface resistance of 20 KΩ / □ or more. 2. An ultrafine particle of a conductive oxide is 100 n.
Antimony-containing tin oxide fine particles or / and tin-containing indium oxide fine particles having an average particle size of m or less, and in terms of oxide, antimony-containing tin oxide or / and tin-containing indium oxide are contained in an amount of 50% by weight or more and ruthenium oxide. Three
The heat ray reflective film according to claim 1, wherein the heat ray reflective film contains 10% by weight or more of a total of silicon oxide, titanium oxide, zirconium oxide, and aluminum oxide in an amount of 10% by weight or more. 3. A coating liquid containing ultrafine particles of a conductive oxide, a ruthenium compound, and at least one selected from a silicon compound, a titanium compound, a zirconium compound, and an aluminum compound as main components. After that, the heat ray reflective film is produced by heating, which is a method for producing the heat ray reflective film. 4. The method for producing a heat ray reflective film according to claim 3, wherein the ruthenium compound contains a ruthenium salt complexed with a chelate ligand. 5. The coating liquid is Si (OR) _m R _n ,
Ti (OR) _m L _n , Zr (OR) _m L _n , Al (O
R) _u L _v (where m + n = 4, m = 1 to 4, n = 0
˜3, u + v = 3, u = 1 to 3, v = 0 to 3, R = C ₁
To C ₄ alkyl group, L = ligand), or at least one kind of these polymers, The method for producing a heat ray reflective film according to claim 3. 6. A glass article having a surface coated with the heat ray reflective film according to claim 1 or 2.