JPS62180740A - Organoindium sol and composite for forming transparent electrically conductive membrane - Google Patents

Abstract

PURPOSE:To maintain membrane forming property and to improve dispersion stability by adding a specified chelating agent to the soln. of a specified indium compd. in a lower alcohol, and treating the soln. with a basic ion-exchange resin. CONSTITUTION:The chelating agent selected from beta-diketone and beta-keto ester is added to the soln. of the indium compd. expressed by the general formula InX3 (X shows a halogen or a nitrate group) in a water-soluble lower alcohol. The soln. is then treated with a basic ion-exchange resin to produce a chelated indium hydroxide-type organoindium sol. A tin compd. is added to the chelated indium hydroxide-type organoindium sol in 0.005-0.30 weight ratio of Sn/In to prepare the composition for forming a transparent electrically conductive membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a stable organoindium sol and a method for forming a transparent conductive film using the same.

Transparent conductive films are used as transparent electrodes of liquid crystal display elements, electroluminescent display elements, photovoltaic cells, photosensitive elements such as image pickup tubes, surface heating element electrodes, and the like.

Many materials are generally known as such transparent electrode materials, including indium oxide-tin oxide or tin oxide-antimony oxide, and transparent conductive films can be obtained by coating and baking them on glass or ceramic substrates. , is used industrially. Among these, indium oxide-tin oxide based oxide films are particularly widely used as ITO (Indium Tin Oxide) films.

The ITO film is formed by vacuum evaporation, sputtering, or CVD.
However, the processing technology is difficult, the processing area is limited, and the physical properties such as film hardness are not satisfactory. There is a need for a composition for

InC15゜I as a composition for ITO film that can be coated
Compositions using inorganic salts such as n(No3)3 and organic compounds such as indicum stone, indium chelate, and indium alkoxide have been proposed, but they have problems with film-forming properties and are difficult to form a uniform film. However, the formed film lacks transparency and becomes cloudy, and the film strength and adhesion are also insufficient. Furthermore, there was a problem of evaporation and transpiration of the ITO film material during firing, and the results were not satisfactory. A method using an inorganic indium sol as a composition for forming an ITO film that has film-forming properties and does not evaporate or dissipate during firing (Japanese Patent Application Laid-Open No.
Cotygto) has been proposed.

Sol compositions containing indium oxide sol as a main component lack stability, as is clear from the behavior of isomorphic sol compositions of aluminum, which is in the same group of the periodic table, and tend to aggregate and separate, resulting in uneven coatings and poor storage stability. The disadvantage was that it was difficult to apply to continuous work, so it was not satisfactory.

However, if an indium sol with stable dispersibility while maintaining film-forming properties is produced, it is expected that a practically preferable ITO film-forming composition will be obtained. As a result of extensive research in search of this, it was discovered that chelate indium hydroxide sol had favorable physical properties, and a method for producing the sol composition and an ITO film composition were also discovered, leading to the present invention.

Thus, the present invention uses β-diketone in a water-soluble lower alcohol solution of an indium compound represented by the general formula In X5 (X represents a halogen or nitric acid group).

Adding a chelating agent selected from β-ketoesters and treating this with a basic ion exchange resin,
The present invention provides a method for producing a chelate indium hydroxide type organoindium sol.

The present invention also provides this chelate indium hydroxide type organoindium sol with Sn/coating. A composition for forming a transparent conductive film obtained by adding a tin compound at a ratio of 0.2 to JO weight % is provided.

The present invention further provides a transparent conductive film obtained by applying a composition for forming a transparent conductive film obtained by adding a covalent tin chelate compound to a chelate indium hydroxide type organoindium sol onto a substrate and baking the composition. be.

To explain in detail, the coating film formed by the coating method is kept at room temperature or
An indium sol that forms a film substantially made of indium oxide containing a predetermined proportion of tin when heated and dried at a low temperature that cannot be fired is an indium sol having 2 or 3 hydroxyl groups. is preferred. but,
Indium sol represented by The efficiency was poor and it was difficult to apply it practically.

When an indium sol is synthesized from an inorganic indium salt, it is treated with an anion exchange resin in the presence of a chelating agent to form an organosol containing monochelate indium dihydroxide as the main component.The resulting sol has good stability and can be heated at room temperature or at room temperature. The primary film forming property when drying by heating at low temperature was also good (excellent as a composition material for ITO film formation). In the production of this organoindium sol, an inorganic indium compound represented by the general formula InX3 is used. X is chlorine, bromine, etc.) or a nitric acid group, and indium chloride and indium nitrate are preferably used. A solution is prepared by dissolving this compound in a water-soluble lower alcohol.

Such alcohols include methanol, ethanol, glopanol, and isopropanol.1. Buta, nol, sec-butanol, tertiary-butanol, etc. may be used alone or in combination of two or more thereof.

A chelating agent selected from β-diketones and β-ketoesters is added to the water-soluble lower alcohol solution of the inorganic indium compound represented by the general formula InX3 thus obtained. Examples of the β-diketone chelating agent include acetylacetone, acetyl methyl ethyl ketone, trifluoroacetylacetone, hexafluoroacetylacetone, benzoylacetone, dibenzoylmethane, benzoylfluoroacetone, and the like. Examples include methyl acetate, ethyl acetoacetate, isopropyl acetoacetate, butyl acetoacetate, and the like. This chelating agent is added in the same molar amount or more to the inorganic indium compound.

After the chelating agent is added to the alcohol solution of the indium compound in this way, it is treated with a basic ion exchange resin. Preferably, a medium or weakly basic ion exchange resin having either a tertiary amine or a quaternary amine as an exchange group is used.

When a chelating agent is added to this 5 and further treated with an ion exchange resin, a chelate reaction and a hydroxide reaction occur, resulting in an organoindium sol containing chelated indium hydroxide as a main component.

The obtained chelate indium hydroxide can be used alone as a material for forming indium oxide and for modifying surface properties.

Further, as the composition for forming an ITO film, it is necessary to use a tin compound that can coexist stably with the organosol and forms a composite oxide with indium hydroxide during coating and drying. As tin compounds, metal soaps and general formula S n
When an inorganic tin compound represented by 4 ・n H2O (X: halogen) is used, a good I
A TO film cannot be formed.

Thus, in the present invention, it is preferable to use a hydrolyzable covalent tin chelate compound which the present inventor has previously researched and developed and applied for a patent. This tin chelate compound has the general formula S n Y 2
It is a compound represented by Here KY is β-diketone,
Indicates a β-keto ester or an amino alcohol substituted with an N alkyl group.

Therefore, in the present invention, the chelate indium hydroxide type organoindium sol includes β-diketones represented by acetylacetone, hexafluoroacetylacetone, trifluoroacetylacetone, pentafluorobenzoylacetone, etc., methyl acetoacetate, ethyl acetoacetate, and acetoacetic acid. β-keto esters represented by isopropyl, butyl acetoacetate, etc., N,N-dimethylamine alcohol, N-methyl N-ethylaminoethanol, N
When a monovalent tin chelate compound chelated with an N-alkyl group-substituted amino alcohol such as N-cy()lyfluoromethyl)aminoethanol is used as the tin component, a transparent conductive film with good film-forming properties and excellent stability can be obtained. A forming composition can be obtained.

Incidentally, the ratio of In-8n can be determined depending on the physical properties, but for forming a transparent ring IT film, it is Sn/N. The ratio is preferably O0S to 30% by weight, and when preparing the composition, if desired, stabilizers such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, succinic acid, maleic acid, Acetylacetone, benzoylacetone, benzoylmethane, methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, butyl acetoacetate, methyl lactate, ethyl lactate, butyl lactate, etc. can also be used.

In some cases, methylcellulose may also be used as a viscosity modifier.
Ethyl cellulose etc. can also be added.

The ITO film can be formed on a substrate by a general method such as a spray method, a dipping method, a bar code method, a roll coating method, a casting method, or a spinner method.

The coated substrate is heated and dried at room temperature or at a low temperature below the firing temperature to form an indium oxide-tin oxide secondary film. This is eoo - in air or under an inert gas atmosphere.
Transparent conductive ITO is formed when baked at zoo℃ for 3θ minutes to 7 hours.
A membrane can be obtained.

The physical properties of the formed transparent conductive ITO film are industrially useful, as the film hardness is a pencil hardness of 4 (H-?H, visible part transmittance is qo% or more, and KΩ sheet resistance is /1).

[Example-7] 700 parts by weight of indium chloride / θ t aqueous ethanol
Dissolve in 20 parts by weight, add parts by weight of acetylacetone SO and 30 Mfk parts of lactic acid, and dissolve uniformly. This solution is mixed with a medium basic ion exchange resin (product name: Amberlite rRA).
-4Ir) /100 parts by volume at a flow rate of S
Treatment with Vλ0H gave a pale yellow transparent effluent. No residual chlorine was detected in the effluent using the silver nitrate method. A portion of the effluent was taken and dried under vacuum to obtain a white amorphous solid. The engineering n203 analysis value of this solid is jt5, Kuchi, I n
(Crystal) (OH)2 (In2O3: 5 j 0g%
), and also from infrared analysis, In(AA)(OH
) It turned out to be 2. This infrared spectrum is shown in the drawing. In the above formula, AA represents acetylacetone. The resulting alcohol solution was applied to a glass plate by roll coating and dried at room temperature, forming a uniform transparent primary oxide film.

[Example-1]

100 parts by weight of indium nitrate was added to ion-exchanged water.

The mixture is dissolved in a mixed solvent of 110 parts by weight of methanol, 110 parts by weight of isopropyl alcohol, and 30 parts by weight of ethyl acetoacetate SO and 30 parts by weight of acetic acid are added thereto and uniformly dissolved. This solution was applied to a column filled with 00 parts by volume of a weakly basic ion exchange resin (trade name: Amberlite IRA-Guyo) at a flow rate of 5v20H to obtain a pale yellow transparent effluent. No residual Nol was found in the effluent when analyzed using an ion meter.

When vacuum-dried and analyzed for In2O5% in the same manner as in Example-1! ? , r % and In(EA)(Of()2(
EA: Ethyl acetoacetate In2O3: ewo, 9%)
In agreement with the results of IR analysis, I n (EA )
It turned out to be (OH)2.

This organosol solution formed a transparent indium oxide film when applied to a glass plate and dried.

[Example 3] To 100 parts by weight of the chelate indium hydroxide sol solution synthesized in Example 7, 10 parts by weight of tin acetylacetone chelate compound (an (AA)2) -10 parts by weight of maleic acid and 1 part by weight of methyl acetoacetate The composition obtained by adding and uniformly dissolving the solution was pale yellow and transparent, and the coating film applied to soda glass by the roll coating method was easily dried at room temperature to obtain a uniform oxide film. When this is fired for q minutes at 1Iro℃, there is no iris, the sheet resistance is 2/D, the visible part transmittance is over 'io%, and the film hardness is pencil hardness? An ITO film with good H content was obtained.

[Example-da]

Chelated indium hydroxy synthesized in Example-1,
To 100 parts by weight of the Tosyl solution, parts by weight of a tin acetoacetate methyl chelate compound (s n (cs H703)2) and parts by weight of acetylacetone were added to 100 parts by weight of the tosyl solution. Transparent, ・By dipping method on soda glass-AI) CrlL 7m
The coating film applied at a pulling speed of 1.5 in. was easily dried at room temperature and a uniform oxide film was obtained. This 1 (3 at ttso℃
After firing for θ minutes, there is no iris, sheet resistance, small mouth at 3,
I'rO with visible part transmittance of 90 cm or more and good film hardness & H
A membrane was obtained.

[Brief explanation of drawings]

The figure is an infrared spectrum of the organoindium sol obtained in Example/.

Claims (1)

[Claims] 1. A chelating agent selected from β-diketones and β-ketoesters is added to a water-soluble lower alcohol solution of an indium compound represented by the general formula InX_3 (X represents a halogen or nitric acid group). , a method for producing a chelate indium hydroxide type organoindium sol, which comprises treating this with a basic ion exchange resin. 2. A composition for forming a transparent conductive film obtained by adding a tin compound to a chelate indium hydroxide type organoindium sol at a Sn/In ratio of 0.5 to 30% by weight. 3. The tin compound has the general formula SnY_2 (Y is β-diketone,
The composition for forming a transparent conductive film according to claim 2, which is a divalent tin chelate compound represented by β-ketoester or N-alkyl group-substituted amino alcohol. 4. A transparent conductive film obtained by applying a composition for forming a transparent conductive film obtained by adding a divalent tin chelate compound to a chelate indium hydroxide type organo-indium sol onto a substrate and baking the composition.