JP3154678B2 - Coating solution for forming a transparent conductive film and glass with a transparent conductive film using the coating solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent conductive metal oxide which is applied to glass, ceramics, etc. and becomes a transparent conductive metal oxide by firing, which can be stored for a long time and which does not generate corrosive gas such as chlorine during firing. The present invention relates to a coating liquid for forming a film and a method for forming the same, and further to a glass with a transparent conductive film having the film formed on a glass substrate.

[0002]

2. Description of the Related Art Transparent conductive films are used for display tubes such as liquid crystal displays, fluorescent display tubes and plasma displays, as well as transparent electrodes or antistatic films for solar cells and touch panels, and for automobiles and aircraft. Widely used for heaters for preventing icing of window glass, heat ray reflective films, etc. Indium oxide and tin oxide films are known as such transparent conductive films.

As a method of manufacturing these films, a physical film forming method such as chemical vapor deposition (CVD) or sputtering is used. However, this method requires a vacuum system, which increases the size of the film forming apparatus and the manufacturing cost. However, there is a drawback that the cost increases. Therefore, a coating method in which a solution of a metal compound of indium and tin is applied to a substrate and fired to adhere a metal oxide film of indium and tin has been considered separately from this method. As an example using this coating method, Japanese Patent Publication No. Sho 60-27
A transparent conductive film is obtained by using an application liquid obtained by reacting indium nitrate, tin and β-diketone described in 130. Japanese Patent Application Laid-Open No. 1-115010 discloses In (O
R ₁ ) _X Cl _3-X (where R ₁ represents an alkyl group or an alkoxyalkyl group having 1 to 10 carbon atoms, and 1.0 ≦ X ≦
2.5) and Sn (OR ₂ ) _Y Cl _nY (where R ₂ represents an alkyl group or an alkoxyalkyl group having 1 to 10 carbon atoms, n is 2 or 4, and when n = 2, 1. 0
In some cases, a transparent conductive film is obtained by applying a coating liquid using ≤Y≤1.8 and 2.5≤Y≤3.5 when n = 4 to a substrate, drying and firing. However, in the case of using these liquids, there is a problem that a large amount of a strong acid or corrosive gas is emitted at the time of drying and firing, and corrodes a device such as a firing furnace.

[0004]

SUMMARY OF THE INVENTION To solve the above-mentioned problems, an intensive study has been made to develop a method for easily and inexpensively producing a transparent conductive film on a glass substrate and to develop a material suitable for the method. As a result, we found an additive for dissolving these compounds in an organic solvent using an indium compound and a tin compound, which do not generate a strongly acidic corrosive gas during firing. The above problem could be solved by preparing the liquid.
Indium fatty acid as an indium compound, fatty acid tin as a tin compound and ethanolamine as an additive are used to add fatty acid indium and fatty acid tin to a form that can be dissolved in an organic solvent, and to hydrolyze the resulting solution. Prevention and long-term stabilization make it possible to prepare a coating solution. Further, this solution is applied to a glass substrate and baked at a temperature of 300 ° C. or higher to form a transparent conductive oxide film, which facilitates the purpose. And reached the present invention.

That is, the present invention provides a coating solution for forming an oxide film excellent in transparency and conductivity, which was not possible with the prior art, at low cost and easily without generating a corrosive gas, and a coating solution for the coating solution. It is an object of the present invention to provide a glass with a transparent conductive film in which a film is formed on a glass substrate by using the production method and the liquid.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The coating solution of the present invention is a coating solution prepared by a conventional method, that is, a coating solution obtained by reacting indium nitrate, tin and β-diketone, and In (OR ₁ ) _X Cl _3-X (here, R
₁ represents an alkyl group or an alkoxyalkyl group having 1 to 10 carbon atoms, and 1.0 ≦ X ≦ 2.5) and Sn (OR ₂ ) _Y
C1 _nY (where R ₂ represents an alkyl group or an alkoxyalkyl group having 1 to 10 carbon atoms, n is 2 or 4, and when n = 2, 1.0 ≦ Y ≦ 1.8, n = 4 In the case of (2.5 ≦ Y ≦ 3.5), there is no generation of a strong acid or a corrosive gas which occurs during drying and baking, and it is advantageous in that it does not corrode equipment such as a baking furnace. Further, since no atmosphere control or the like is required at the time of preparing the coating liquid, the production cost is very low and it is economically advantageous.

In the method for producing a coating solution of the present invention, first, indium fatty acid and tin fatty acid are mixed in an organic solvent so that the Sn concentration becomes 0.01 to 0.3 (molar ratio) with respect to the In concentration. . In consideration of conductivity, the ratio of the In amount and the Sn amount is preferably the above molar ratio.

Examples of the indium fatty acid used as the In raw material include indium acetate, indium propionate, and the like. Fatty acid salts having a large number of carbon atoms have a large weight loss during thermal decomposition. preferable.

As the fatty acid tin used as the Sn raw material, tin acetate, tin propionate, tin caproate,
And tin ethylhexanoate.

The organic solvents used include methanol, ethanol, n-propanol, i-propanol and n-propanol.
Examples thereof include alcohol solvents such as butanol, i-butanol and 2-butanol, glycols such as ethylene glycol and propylene glycol, and glycol ethers such as methoxyethanol, ethoxyethanol and isopropoxyethanol. Of these organic solvents,
One kind may be used, or two or more kinds may be used in combination. As the amount of the organic solvent, the In concentration was 0.0
An amount of 5 to 2 mol / l is preferred. This amount is to maintain the indium concentration in the liquid at an appropriate value and to make the viscosity suitable for coating.If the solvent is large, the indium concentration will be low, and the coating thickness will be small and the conductive film will not be sufficient. Is not preferred. On the other hand, if the amount of the solvent is small, the viscosity becomes high, which makes the composition unsuitable as a coating liquid, which causes cracks in the coating film or a film having low visible light transmittance.

The mixed solution of the fatty acid indium, the fatty acid tin and the organic solvent exists in a state where the fatty acid indium is not dissolved but is dispersed or precipitated as a solid, and cannot be used as a coating solution as it is. By adding an appropriate amount of ethanolamine to this, all of the fatty acid indium is dissolved, and a homogeneous and stable transparent solution is obtained. In addition, the fatty acid tin is rapidly hydrolyzed, and if used as a solution as it is and used as a coating solution, the coating film is rapidly hydrolyzed by moisture in the air during drying and whitens. Therefore,
By adding ethanolamine and coordinating ethanolamine to the fatty acid tin, the amount of fatty acid tin hydrolyzed by atmospheric moisture was successfully reduced, and this problem was solved to arrive at the present invention. . Therefore, ethanolamine completely dissolves the fatty acid indium in the organic solvent,
In addition, it suppresses the hydrolysis of the fatty acid tin oxide and plays a role of keeping the film coated with this solution transparent and homogeneous.

The amount of ethanolamine to be added is 1 (mol) based on the total mole of fatty acid indium and fatty acid tin.
Ratio), the dissolution of fatty acid indium is insufficient.
At the time of application, undissolved fatty acid indium particles were precipitated,
A coating film having a rough surface is not obtained, and hydrolysis of fatty acid tin is not sufficiently suppressed. The coating film is hydrolyzed by moisture in the air, and the coating film is whitened. On the other hand, if the amount of ethanolamine to be added is more than 8 (mol ratio) with respect to the total mole of fatty acid indium and fatty acid tin, the coating film will be uneven, and the film thickness will not be uniform. Therefore, the amount of ethanolamine to be added is preferably 1 to 8 (molar ratio) with respect to the total mole of fatty acid indium and fatty acid tin.

The ethanolamine to be added includes monoethanolamine, diethanolamine, and triethanolamine. One of them may be used, or two or more of them may be used.

The solution obtained by the above-described production method is optimal as a coating solution for forming a dense indium oxide-based oxide film having transparent conductivity.

[0015] Spraying, roll coating, spin coating, dipping, and the like are excellent methods for easily producing a uniform film. After a coating film is formed on the surface of the glass substrate by the above method, drying is performed at 70 to 200 ° C. for 10 to 30 minutes to remove the organic solvent, and firing is performed at a temperature of 300 ° C. or more for 10 minutes to 2 hours. . The firing may be performed in the air or oxygen, and in some cases, the firing may be performed in an inert atmosphere (eg, nitrogen or argon) or a reducing atmosphere. By this method, a transparent and highly conductive indium oxide-based oxide film can be obtained.

As described above, since the coating solution of the present invention does not contain ions such as Cl, NO ₃ and SO _{4 in the} solution, the gas generated upon drying and firing does not show strong acidity and corrosiveness.
A glass with a transparent conductive film can be produced easily at low cost and with good productivity without corroding equipment such as a drying and firing furnace. Further, since the glass with a transparent conductive film obtained by the present invention has both excellent visible light transmittance and conductivity, it is widely used in the fields of transparent electrodes for displays, antistatic films, anti-fog glass, touch switches, and the like. It is thought that there is.

[0017]

【Example】

Example 1 0.1 mol of indium acetate and 0.001 mol to 0.03 mol of tin 2-ethylhexanoate were mixed and stirred in 1000 ml of n-propanol, and 0.2 mol of diethanolamine and 0.2 mol of monoethanolamine were added to the mixture. And mix for 1 hour. Indium acetate was completely dissolved by the reaction with diethanolamine and monoethanolamine, and a transparent coating solution for forming an indium oxide-based composite oxide film was obtained. These coating solutions were very stable, and remained transparent without any precipitation or cloudiness of the solution after being left at room temperature for one year. The slide glass was immersed in the thus-prepared coating solution for forming an indium oxide-based composite oxide film, and pulled up at a rate of 10 cm / min to form a coating film. These coating films are
After drying at 30 ° C. for 30 minutes, the organic solvent was removed and the film was cured. Then, firing was performed in an electric furnace at 550 ° C. for 30 minutes in the air, and further firing was performed at 300 ° C. for 30 minutes in a nitrogen atmosphere to obtain an indium oxide-based composite oxide film. FIG. 1 shows the surface resistance value of the glass with a transparent conductive film of this example. Further, it was found that all of the obtained glasses with a transparent conductive film had a very high visible light transmittance of 90%.

Example 2 0.5 mol of indium acetate and 0.027 mol, 0.075 mol, 0.133 m of tin 2-ethylhexanoate
ol was mixed and stirred in 1000 ml of n-propanol, and 1.0 mol of diethanolamine was added to the mixture.
And 1.0 mol of monoethanolamine were added.
Mix for hours. Indium acetate was completely dissolved by the reaction with diethanolamine and monoethanolamine, and a transparent coating solution for forming an indium oxide-based composite oxide film was obtained. These coating solutions were very stable, and remained transparent without any precipitation or cloudiness of the solution after being left at room temperature for one year. The slide glass was immersed in the coating solution for forming an indium oxide-based composite oxide film prepared in this manner,
It was pulled up at a speed of 0 cm / min to form a coating film.
After drying these coating films at 180 ° C. for 30 minutes to remove the organic solvent and cure the films, the coating films were dried at 550 ° C. in an electric furnace.
Firing was performed in the air for 30 minutes, and further, in a nitrogen atmosphere at 300 ° C. for 30 minutes to obtain an indium oxide-based composite oxide film. FIG. 1 shows the surface resistance value of the glass with a transparent conductive film of this example. Further, it was found that all of the obtained glasses with a transparent conductive film had a very high visible light transmittance of 88% or more. A cross cut tape test was performed to examine the adhesion of the obtained transparent conductive film. As a result, it was found that all the films were 100/100 and had good adhesion without any peeling.

Example 3 0.5 mol of indium acetate and 0.038 mol of tin 2-ethylhexanoate were added to 1000 ml of n-propanol.
The mixture was stirred and mixed, and 1.0 mol of diethanolamine and 1.0 mol of monoethanolamine were added to the mixture.
And mix for 1 hour. Indium acetate reacts with diethanolamine and monoethanolamine,
A completely dissolved and transparent coating solution for forming an indium oxide-based composite oxide film was obtained. This coating solution is very stable,
Even after standing at room temperature for one year, no precipitation or cloudiness of the solution was observed, and the solution remained transparent. The slide glass was immersed in the thus-prepared coating solution for forming an indium oxide-based composite oxide film, and pulled up at a rate of 10 cm / min to form a coating film. This coating film was dried at 180 ° C. for 30 minutes to remove the organic solvent and cure the film, and then 550 in an electric furnace.
Calcination was carried out in the air at 30 ° C. for 30 minutes to obtain a uniform indium oxide-based composite oxide film having a thickness of 0.1 μm on one side. The surface resistance of the glass with a transparent conductive film of this example was 500 Ω /
It was □. Further, it was found that the visible light transmittance was as high as 90%. A cross cut tape test was performed to examine the adhesion of the obtained transparent conductive film. The result is 100 /
100 was found to be a film having good adhesion without any peeling.

Example 4 0.5 mol of indium octylate and 0.027 mol of tin 2-ethylhexanoate were added to 1-propanol 1000
The mixture was stirred and mixed with 1.0 mol of diethanolamine and 1.0 mol of monoethanolamine.
1 and mix for 1 hour. Indium octylate was completely dissolved by the reaction with diethanolamine and monoethanolamine, and a transparent coating solution for forming an indium oxide-based composite oxide film was obtained. This coating solution was very stable, and remained clear without any precipitation or cloudiness of the solution after being left at room temperature for one year. The slide glass was immersed in the thus-prepared coating solution for forming an indium oxide-based composite oxide film, and pulled up at a rate of 10 cm / min to form a coating film. This coating film was dried at 180 ° C. for 30 minutes to remove the organic solvent and cure the film, and then fired in an electric furnace at 550 ° C. for 30 minutes in the air to form a film having a thickness on one side of 0.1.
A uniform indium oxide-based composite oxide film having a thickness of μm was obtained.
The surface resistance of the glass with a transparent conductive film of this example is 1
000Ω / □. Further, it was found that the visible light transmittance was as high as 90%. A cross cut tape test was performed to examine the adhesion of the obtained transparent conductive film. The result was 100/100, indicating that the film had good adhesion without any peeling.

Example 5 0.5 ml of indium acetate and 0.038 mol of tin 2-ethylhexanoate were added to 1000 ml of n-propanol.
The mixture is stirred and mixed in the mixture, and 0.75 mol of diethanolamine and 0.25 m
and mix for 1 hour. Indium acetate was completely dissolved by the reaction with diethanolamine and monoethanolamine, and a transparent coating solution for forming an indium oxide-based composite oxide film was obtained. This coating solution was very stable, and remained clear without any precipitation or cloudiness of the solution after being left at room temperature for one year. The slide glass was immersed in the thus-prepared coating solution for forming an indium oxide-based composite oxide film, and pulled up at a speed of 20 cm / min to form a coating film. The coated film was dried at 180 ° C. for 30 minutes to remove the organic solvent and cure the film, and then fired in an electric furnace at 550 ° C. for 30 minutes in an oxygen atmosphere. Thereafter, the resultant was fired at 550 ° C. for 30 minutes in a nitrogen atmosphere to obtain a uniform indium oxide-based composite oxide film having a thickness of 0.1 μm on one side. The surface resistance of the glass with a transparent conductive film of this example was 80 Ω / □. Further, it was found that the visible light transmittance was as high as 89%. A cross cut tape test was performed to examine the adhesion of the obtained transparent conductive film. The result was 100/100, indicating that the film had good adhesion without any peeling.

From the results of the above Examples, the coating solution of the present invention is stable for a long time, and the glass with a transparent conductive film obtained from the coating solution is excellent in terms of visible light transmittance and conductivity. It became clear that there was.

[0023]

The coating solution for forming an indium oxide-based oxide film of the present invention is stable for a long time without being affected by moisture or the like, and can be applied to a glass substrate, dried and fired to obtain a visible light region. Shows high transmission characteristics for light,
In addition, it becomes a dense film having excellent conductivity. In addition, since the coating solution of the present invention does not contain ions such as Cl, NO ₃ , and SO ₄ in the solution, the gas generated during drying and firing does not show strong acid and corrosiveness. This makes it possible to produce a glass with a transparent conductive film easily at low cost and with good productivity without corroding the apparatus.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the amount of Sn / In and the surface resistance of a fired film.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuyuki Ohara 2-9-29 Kamimaezu, Naka-ku, Nagoya-shi, Aichi Tsuchi Indoor Co., Ltd. (56) References JP-A-54-9792 (JP, A) JP-A Sho 57-27504 (JP, A) JP-A-60-97504 (JP, A) JP-A-60-117503 (JP, A) JP-A-57-67048 (JP, A) JP-A-1-115010 (JP, A) A) JP-A-10-324820 (JP, A) JP-A-11-49990 (JP, A) JP-A-9-194826 (JP, A) JP-A-60-49509 (JP, A) JP-A-56 JP-A-5-5356 (JP, A) JP-A-56-5357 (JP, A) JP-A-60-184577 (JP, A) JP-A-63-46274 (JP, A) JP-A-1-159910 (JP, A) JP-A-59-27965 (JP, A) JP-A-1-246396 (JP, A) JP-A-2-267812 (JP, A) JP-A-2-281505 (JP, A) JP-A-6-234522 (JP, A) JP-A-6-247716 (JP, A) JP-A-7-144917 (JP, A) JP-A-8-143792 (JP) , A) JP-A-9-161561 (JP, A) JP-A-11-61005 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 1/00-201/10 C03C 17/00-17/44 H01B 1/00-1/24 H01B 13/00 C01G 15/00 C01G 19/02 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] The present invention relates to a fatty acid of the formula In (OCOR) ₃ (wherein R represents a linear or branched alkyl group having 1 to 8 carbon atoms) relative to the molar concentration of indium and indium.
1-0.3 molar concentration of the formula Sn (OCOR ') ₂ (where
R ′ represents a straight-chain or branched-chain alkyl group having 1 to 8 carbon atoms) and 1 to 8 per mole of the total thereof.
A coating liquid for forming an indium oxide-based transparent conductive film comprising a molar ratio of ethanolamine. 2. The fatty acid of the formula In (OCOR) ₃ (wherein R represents a straight-chain or branched-chain alkyl group having 1 to 8 carbon atoms) and the molar concentration of indium and indium are 0.0
1-0.3 molar concentration of the formula Sn (OCOR ') ₂ (where
R ′ represents a linear or branched alkyl group having 1 to 8 carbon atoms) with a fatty acid tin in an organic solvent, and further adding ethanolamine to form a clear solution. A method for producing a coating liquid for forming an indium oxide-based transparent conductive film.