JPH05120921A - Transparent conductive film and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a transparent conductive film without needing any complicated device at a comparatively low temperature. CONSTITUTION:Coating liquid, which contains at least one kind of aluminum complexes (aluminum salt, aluminum alkoxide, hydrolyzed stuff of aluminum alkoxide), for instance, Al(C6H9O3) (OR)2 and the ultrafine particles of conductive oxide, is applied onto a substrate, and is cured so as to form a transparent film.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a transparent conductive film formed on the surface of a glass or transparent plastic substrate.

[0002]

2. Description of the Related Art Conventionally, in order to form a transparent conductive film on a transparent substrate, a physical process such as a CVD method using a metal chloride or an organometallic compound as a raw material, a thermal decomposition method, a sputtering method or an evaporation method is used. Techniques have been used. However, these methods have problems that they cannot be used for plastics and glass products that require dimensional accuracy because they require high-temperature treatment, and that complicated devices are required.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks of the prior art, and to newly provide a transparent conductive film which can be heat-treated at a low temperature without requiring a complicated apparatus. It is intended to be provided.

[0004]

The present invention has been made to solve the above-mentioned problems, and is a coating containing an aluminum complex having a chelate ligand coordinated to aluminum and ultrafine particles of a conductive oxide. The present invention provides a method for producing a transparent conductive film, which comprises applying a liquid onto a substrate and curing the liquid.

Ultrafine particles of conductive oxide include SnO ₂ doped with Sb and F, conductive titanium oxide, and ITO.
(Sn-doped In ₂ O ₃ ), RuO ₂ , and Sn
Examples thereof include composite oxides such as O ₂ —RuO ₂ and TiO ₂ —RuO ₂ .

The average particle size of the conductive oxide ultrafine particles is 1
It is preferably 000Å or less. More preferably 5
It is desirable that it is 00 Å or less, and particularly preferably 200 Å or less. The use of particles having a particle size of 1000Å or more may impair the transparency of the transparent conductive film.
It also adversely affects the film strength.

It is important that these conductive oxide ultrafine particles are uniformly dispersed in water to form an aqueous sol. When dispersing, it is desirable to stir to facilitate contact between the solution and the powder. In this case, a commercially available crusher such as a colloid mill, a ball mill, a sand mill or a homomixer can be used. Also, when dispersing, 20 to
It is also possible to heat in the range of 200 ° C. When stirring above the boiling point of the solution, pressurize to maintain the liquid layer. Thus, an aqueous sol in which the conductive oxide is dispersed as colloidal particles can be obtained.

The liquid in which the ultrafine particles of the conductive oxide are dispersed contains an aluminum complex having a chelate ligand coordinated with aluminum in order to prevent the fine particles from aggregating and precipitating and forming a stable sol. It is preferable to add it.

Examples of such an aluminum complex include at least one selected from an aluminum salt, an aluminum alkoxide, and a hydrolyzate of an aluminum alkoxide in which a chelate ligand is coordinated with aluminum to form a complex. Further, as the chelate ligand,
Examples thereof include enol type anions of β-diketone and β-keto acid ester. As a typical example of the aluminum complex, Al (C ₆ H ₉ O ₃ ) (OR) ₂ (C ₆ H ₉ O ₃ is an enol type anion of ethyl acetoacetate, R = C
₁ alkyl group -C ₄₎ can be mentioned.

By doing so, the chelate ligand such as β-diketone wraps around the fine particles, and the steric hindrance effect is formed, and the outermost surface of the chelate ligand such as β-diketone is positively charged. Due to the electric double layer, fine particles repel each other and a stable sol liquid can be formed. In order to obtain this effect, the addition amount of such an aluminum complex is SnO ₂ : Al in terms of oxide (weight ratio).
₂ O ₃ = 1: 0.05 to 1.0, preferably 1: 0.1
It is better to set it to 0.3. By adding this to the sol of conductive fine particles, the sol of conductive fine particles can be stabilized.

The enol type anion of β-diketone or β-keto acid ester, which is a typical example of the chelating ligand, is acetylacetone, trifluoroacetylacetone, benzoylacetone, hexafluoroacetylacetone, benzoyltrifluoroacetylacetone, dibenzoylmethane. And anions such as acetoacetic acid methyl ester, acetoacetic acid ethyl ester, and acetoacetic acid butyl ester.

The aqueous sol in the present invention can be used as it is, but it can also be used by dispersing or substituting it in an organic solvent in order to enhance the coating property on the substrate. As the hydrophilic organic solvent, alcohols such as methanol, ethanol, 2-propanol and ethylene glycol, and ethers such as ethyl cellosolve can be arbitrarily used.

The coating solution used in the present invention contains Si (OR) _y R _4-y (y = 3 or 4, as a binder to improve the adhesion strength and hardness of the film.
It is also possible to add a silicon compound such as R: alkyl group). Further, various surfactants can be added to improve the wettability with the substrate. It is also possible to obtain a film having a high refractive index by mixing a Ti compound, a Zr compound or the like with the coating liquid.

As a coating method of the coating liquid thus synthesized on the substrate, there have been conventionally used methods such as spin coating method, dip coating method, spray coating method, roll coating method, meniscus coating method and screen printing. Method, flexographic printing method, etc. can be used.

When the coating liquid of the present invention uses a solvent having a low boiling point, a uniform film can be obtained by drying at room temperature. However, when a solvent having a high boiling point is used or the strength of the film is desired to be improved,
Heat the coated substrate (if the substrate is glass, room temperature to 6
It is preferable to cure by irradiating with ultraviolet rays and / or about 50 ° C.). The upper limit of the heating temperature is determined by the softening point of glass, plastic, etc. used for the substrate.

As the substrate for forming the transparent conductive film of the present invention, in addition to ordinary ordinary plate glass or float plate glass, a cathode ray tube panel, a glass plate for a copying machine, a CRT or an LCD.
It is possible to use various kinds of glass such as a front plate of a display device such as, and a plastic substrate.

The transparent conductive film according to the present invention, in addition to its function as an antistatic film utilizing its conductivity, is made of an ultrafine particle of a conductive oxide, such as ITO or Sb-SnO _2, which has a heat ray reflecting property. If used, it can have a function as a heat ray reflective film. Furthermore, since it is a discontinuous film in which conductive particles are highly dispersed in the film, electromagnetic waves can be transmitted by controlling the film thickness and adjusting the resistance value, etc., and it can be used as an indoor antenna or a glass antenna for automobiles. And the like can be used as a heat ray reflective film that can be used in combination.

Similarly, a liquid containing a material having a low refractive index such as MgF ₂ or SiO ₂ is coated on the transparent conductive film of the present invention so as to have an appropriate optical film thickness, and a multilayer interference effect is obtained. It is also possible to use a low-reflection transparent conductive film.

[0019]

The present invention will be further described below with reference to examples of the present invention, but the present invention is not limited thereto.

Example 1 A SnO ₂ sol liquid obtained by crushing Sb-doped SnO ₂ having an average particle size of 100 Å with a sand mill was diluted with ethanol to 3% by weight. In (A _{solution) Al (C 6 H 9 O} 3) (OC 3 H 7) 2 ethanol _{solution, Al (C 6 H 9 O} 3) a (OC ₃ H ₇₎ aqueous hydrochloric acid relative to the ₂ 5 parts by weight 2 parts by weight was added and stirred for 30 minutes to prepare an Al ₂ O ₃ conversion solid content concentration of 3% by weight. (Solution B) Solution A and Solution B were mixed in a ratio of Solution A: Solution B = 10: 1 by weight. (C liquid)

The ethanol solution of _{Si (OC 2 H 5) 4} , Si (OC 2 H 5) aqueous solution of hydrochloric acid, 4 parts by weight was added with respect to ₄ 5 parts by weight, SiO ₂ in terms of solid concentration of 3 wt% Was prepared as follows. (D liquid) C liquid and D liquid were mixed in a ratio of C liquid: D liquid = 17: 8 weight ratio, and this solution was 750 rp on the surface of a 2 mm thick glass plate.
The coating was performed by a spin coating method for 5 seconds and then heated at 200 ° C. for 30 minutes.

[Example 2] Liquid A and liquid B were liquid A: liquid B = 1
Same as Example 1 except that the mixture was mixed at a ratio of 0: 2 (solution E), and the solution E was used instead of the solution C so that the solution E: solution D was mixed at a ratio of 3: 2 by weight. Went to.

[0023] [Example _{3] Al (OC 4 H 9} ) 3 in ethanol in acetylacetone Al (OC ₄ H _{9) 3}
After adding 1 mol ratio to and stirring for 1 hour, Al (O
1 part by weight of an aqueous solution of hydrochloric acid was added to 5 parts by weight of C ₄ H ₉ ) ₃ , and the mixture was further stirred for 1 hour so that the solid content concentration became 3% by weight in terms of Al ₂ O ₃ . (F liquid)

Solution D and solution F shown in Example 1 were prepared as solution D:
Liquid F was mixed so that the weight ratio was 8: 2. (Solution G) The same operation as in Example 2 was carried out except that instead of the solution D, the solution G was used and mixed so that the solution E: the solution G was 3: 2.

Example 4 A SnO ₂ sol liquid obtained by crushing Sb-doped SnO ₂ having an average particle size of 100Å with a sand mill was diluted with ethanol to 10% by weight. To (H _{solution) Al (C 6 H 9 O} 3) (OC 3 H 7) 2 ethanol _{solution, Al (C 6 H 9 O} 3) a (OC ₃ H ₇₎ nitric acid aqueous solution for _two 5 parts by weight 2 parts by weight was added and stirred for 30 minutes to prepare an Al ₂ O ₃ conversion solid content concentration of 10% by weight. (Liquid I)

Solution H and solution I were mixed so that the ratio of solution H: solution I was 10: 3 by weight, and this solution was applied onto a surface of a 2 mm thick glass plate by a spin coating method at 750 rpm for 5 seconds, and then 600 Heated at 0 ° C for 5 minutes.

[Example 5] Acetylacetone was added to Al (O) in an isopropyl alcohol solution of Al (OC ₄ H ₉ ) _3.
After adding 1 mol ratio to C ₄ H ₉ ) _{3 and} stirring for 30 minutes, 2 parts by weight of hydrochloric acid aqueous solution was added to 5 parts by weight of Al (OC ₄ H ₉ ) ₃ and further stirred for 1 hour, and Al ₂ It was prepared so that the solid content concentration in terms of O ₃ would be 10% by weight. (J
Solution) Solution H and Solution J shown in Example 4 were prepared as Solution H: Solution J = 10:
It mixed so that it might become 1 weight ratio. (K liquid)

Ethyl silicate polymer (solid content of SiO ₂ 4
0% by weight) of ethanol solution was added with 4 parts by weight of hydrochloric acid aqueous solution to 5 parts by weight of ethyl silicate polymer to prepare a solid content concentration of 10% by weight in terms of SiO ₂ . (L
Liquid) The L liquid and the K liquid were mixed so as to have a L liquid: K liquid = 11: 4 weight ratio to form a coating liquid, and a transparent conductive film was obtained in the same manner as in Example 4.

[Example 6] The same procedure as in Example 5 was repeated except that the solution I was used instead of the solution J.

Example 7 The coating solution used in Example 3 was stored in a thermostatic oven at 35 ° C. for 2 weeks and then coated in the same manner as in Example 3.

[Comparative Example 1] The same procedure as in Example 1 was carried out except that the liquid A was used instead of the liquid C.

[Comparative Example 2] The same operation as in Example 5 was carried out except that the H solution was used instead of the K solution.

The films obtained in the above Examples and Comparative Examples were evaluated for the surface resistance value of the film surface, visible light transmittance, and haze. The results of Examples and Comparative Examples are shown in Table 1. Also, for Example 5, 300 nm
The spectral transmittance of ˜2600 nm was measured, and the heat ray reflection performance was evaluated. The result is shown in FIG. Compared with the spectral transmittance of the glass before forming the film, the spectral transmittance after forming the film of Example 5 is considerably low in the near infrared to infrared region. It can be seen that the heat ray reflection performance is high.

[0034]

[Table 1]

[0035]

According to the present invention, an excellent transparent conductive film can be efficiently provided by a simple method such as spraying, spin coating or immersing a substrate in a solution. Since the present invention is excellent in productivity and does not require a vacuum, the device may be relatively inexpensive. In particular, it has a very high industrial value because it can be sufficiently applied to large-area substrates such as plate glass for buildings and buildings, glass for automobiles, and panel face surfaces of CRTs, and mass production is possible.

By adding an aluminum complex in which a chelate ligand is coordinated to aluminum, conductive particles such as SnO ₂ are stably dispersed in the coating liquid, and a high performance film with less haze can be obtained.

[Brief description of drawings]

FIG. 1 is a graph showing the spectral transmittance of the film obtained in Example 5.

Claims (8)

[Claims] 1. A method for producing a transparent conductive film, which comprises applying a coating solution containing an aluminum complex having a chelate ligand coordinated to aluminum and ultrafine particles of a conductive oxide to a substrate and curing the coating solution. .. 2. The aluminum complex is at least one selected from an aluminum salt, an aluminum alkoxide, and a hydrolyzate of an aluminum alkoxide in which a chelate ligand is coordinated with aluminum. 1. The method for producing a transparent conductive film of 1. 3. The chelate ligand is β-diketone or β-
3. The method for producing a transparent conductive film according to claim 1, which is an enol type anion of keto acid ester. 4. The method for producing a transparent conductive film according to claim 1, wherein the coating liquid contains a silicon compound. 5. A transparent conductive film obtained by the manufacturing method according to claim 1. 6. A glass article having a transparent conductive film formed on a glass substrate by the manufacturing method according to claim 1. 7. A glass comprising a transparent conductive film formed on the surface by the manufacturing method according to any one of claims 1 to 4 and having heat ray reflection performance thereby. 8. A CRT having a transparent conductive film formed on its surface by the manufacturing method according to any one of claims 1 to 4, thereby providing antistatic performance.