JPH05234433A - Manufacture of conductive film - Google Patents

Abstract

PURPOSE:To obtain a high characteristic conductive film to which low- temperature thermal treatment is applicable, by applying an application liquid including a rhenium compound and other metal compounds to a base body and then subjecting to heating. CONSTITUTION:An application liquid including a rhenium compound and other metal compounds is applied to a base body and then heated to make a condutive film containing rhenium oxide. As a metal compound except for the rhenium compound, at least one kind selected from Si compounds, Zr compounds Ti compounds and Al compounds which make respectively SiO2, ZrO2, TiO2 and Al2O3 by heating, can be listed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive film applied on the surface of a glass substrate such as a cathode ray tube panel.

[0002]

2. Description of the Related Art Since a cathode ray tube operates at a high voltage, static electricity is induced on its surface at the time of starting or ending. This static electricity often causes dust to adhere to the surface to cause a reduction in contrast, or causes discomfort due to a slight electric shock when directly touched.

In the past, many attempts have been made to provide an antistatic film on the surface of a cathode ray tube panel in order to prevent the above-mentioned problems. For example, as described in JP-A-63-76247, the surface of the cathode ray tube panel is heated to about 350 ° C. to perform CV.
A method of providing a conductive oxide layer such as tin oxide and indium oxide by the D method has been adopted. However, in this method, there is a problem in that in addition to the cost of the apparatus, since the CRT is heated to a high temperature, the fluorescent substance in the CRT falls off and the dimensional accuracy decreases. Further, tin oxide is the most common material used for the conductive layer, but in this case, there is a drawback that it is difficult to obtain a high performance film by low temperature treatment.

In recent years, radio wave interference to electronic equipment due to electromagnetic noise has become a social problem, and standards have been created and regulated to prevent them. Electromagnetic noise is considered to be a problem in various countries in the human body, such as fear of skin cancer due to electrostatic charge on the CRT, influence on the fetus due to low-frequency electromagnetic field (ELF), and harm due to X-rays and ultraviolet rays. In this case, when an electromagnetic wave hits the conductive coating film due to the presence of the conductive coating film, an eddy current is induced in the coating film and the electromagnetic wave is reflected by this action. However, for this purpose, it is necessary to have good conductivity having electric characteristics comparable to those of metals capable of withstanding high electric field strength, but it has been more difficult to obtain a film having such good conductivity.

[0005]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks of the prior art, and an object thereof is to newly provide a high-performance conductive film which can be heat-treated at a low temperature. To do.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, in which a coating solution containing a rhenium compound and another metal compound is applied on a substrate and then heated. And a method for manufacturing a conductive film containing rhenium oxide.

The coating liquid used in the present invention contains a rhenium compound as an essential component. Examples of such rhenium compounds include rhenium salts such as rhenium chloride,
Examples thereof include acid chlorides such as rhenium oxytetrachloride and salts such as sodium perrhenate.

The rhenium compound such as rhenium chloride can be used as it is after being dissolved in water, but it can also be used by being dispersed in an organic solvent in order to improve the coating property to the substrate. As the hydrophilic organic solvent, alcohols such as methanol, ethanol, propanol and butanol, and ethers such as ethyl cellosolve can be arbitrarily used.

The coating liquid containing the rhenium compound used in the present invention is a liquid containing a metal compound other than the rhenium compound. Examples of such metal oxides include at least one of a Si compound, a Zr compound, a Ti compound, and an Al compound, which become SiO ₂ , ZrO ₂ , TiO ₂ , and Al ₂ O ₃ by heating. Specifically, Si,
At least one of Zr, Ti, Al alkoxides, hydrolysates thereof, and salts is used.

Above all, the coating liquid contains Si (OR) as a binder for improving the adhesion strength and hardness of the film.
_It is preferable to add a Si compound such as _y · R ′ _4-y (y = 3 or 4, R and R ′ are alkyl groups), or a hydrolyzate thereof. At that time, HC is used as a hydrolysis catalyst.
1, HNO ₃ , CH ₃ COOH, HCOOH, etc. can be added.

The addition ratio of the Si compound is, in terms of oxide, the weight ratio of rhenium oxide ReO ₃ and silicon oxide.
ReO ₃ : SiO ₂ = 1: 6 to 5: 1 or less is preferable.
If the amount of ReO ₃ is too small, the surface resistance value of the conductive film will be high, and if the amount of SiO ₂ is too small, the adhesive strength between the conductive film and the substrate (especially in the case of a glass substrate) will be weak. Therefore,
As a range capable of expressing sufficient conductivity and adhesive strength,
Such weight ratio is preferred.

Further, as described above, a conductive film having a high refractive index can be obtained by adding the Ti compound, the Zr compound and the Al compound to the coating liquid.

The solid content of the coating solution is 0.05 to 30.
It is preferably wt%, more preferably 0.3
~ 10.0% by weight. If the solid content is too small, the viscosity of the coating liquid will be small, and the film will be thin, so that the uniformity and sufficient conductivity of the film will not be obtained, and if it is too large, the storage stability of the coating liquid will be poor. Therefore, such solid content is preferable. Further, in order to improve the wettability with the substrate, various surfactants can be added to the coating liquid.

As a method for applying the coating liquid onto the substrate, conventionally known methods, that is, spin coating, dip coating, spray coating and the like can be preferably used. Further, spray coating may be performed to form irregularities on the film surface to impart an antiglare effect together, and in that case, a hard coat such as a silica coating may be provided on the conductive film having the irregularities.

As a substrate for forming the conductive film of the present invention, a cathode ray tube panel, a glass plate for a copying machine, a computer panel,
It is possible to use glass for a clean room, various kinds of glass such as a front plate of a display device such as a CRT or LCD, a plastic substrate and the like.

The coating solution in the present invention is directly coated on the substrate. When a low boiling point solvent is used, it is possible to obtain a uniform film by drying at room temperature, but when a high boiling point solvent is used or in order to improve the strength of the film, it is heated after coating. Preferably. The upper limit of the heating temperature is determined by the softening point of glass, plastic, etc. used for the substrate. Considering this point, the preferable temperature range is 100
~ 500 ° C.

As described above, a coating liquid containing a compound such as Zr, Ti or Al is used to form a conductive film having a high refractive index, and a low refractive material such as MgF ₂ or SiO ₂ is formed on the conductive film. Coated with a liquid containing a so as to have an appropriate optical film thickness,
It is also possible to use a conductive film having a low reflection due to the multilayer interference effect. At that time, after applying the coating liquid for forming a conductive film, it is dried,
Then, the liquid for forming the low refractive index film may be applied and heated at the same time.

[0018]

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 solution prepared by adding rhenium trichloride to ethanol so as to be 3% by weight in terms of ReO ₃ , and hydrolyzing ethyl silicate to make ethanol 3% by weight in terms of SiO _2. The added solution was mixed so as to have various ratios in terms of oxide (ReO ₃ , SiO ₂ ) on the surface of a glass plate having a diameter of 70 mm at various rotation speeds for 5 seconds by a spin coating method, and then variously applied. Heated at the temperature of. Table 1 shows the surface resistance value of the film formed as a result.

[0020]

[Table 1]

Example 2 The same rhenium trichloride solution as in Example 1, a hydrolyzate-containing solution of ethyl silicate, and
Liquid containing Ti (AcAc) ₂ (OC ₃ H ₇ ) ₂ (where AcAc is acetylacetone), Al (C ₆ H ₁₀ O
₃ ) A solution containing (OC ₃ H ₇ ) ₂ and a solution containing ZrCl ₄ are mixed at various ratios to prepare a coating solution, which is applied to a glass plate surface having a diameter of 70 mm by a spin coating method at a rotation speed of 750 times / minute for 5 seconds. It was applied and heated at 380 ° C. for 10 minutes to obtain various conductive films. Solid content concentration (wt%) of each component in each coating solution,
Table 2 shows the surface resistance value (Ω / □) of the obtained conductive film.
Shown in.

[0022]

[Table 2]

Example 3 Example 3 was repeated except that the rhenium compound in Example 2 was changed to ReCl ₄ . The results are shown in Table 3.

[0024]

[Table 3]

[Example 4] Rhenium oxide chloride was dissolved in H ₂ O and adjusted to be 20% by weight in terms of ReO ₃ . Further, this solution was diluted with ethanol and adjusted so that the solid content was 3.0% by weight. Si (OEt) ₄ was dissolved in ethanol to a solid content of 3.0% by weight,
Rhenium oxide chloride solution and ReO ₃ : SiO ₂ = 1: 1
The mixture was mixed at a ratio of 2: 1 and the coating solution was prepared by hydrolyzing Si (OEt) ₄ using HCl generated during decomposition of rhenium oxychloride as a catalyst. A plate glass was spin-coated with this solution at 750 rpm for 5 seconds and heated at 380 ° C. for 10 minutes to form a film. Table 4 shows the solid content weight ratio of each component in each coating solution and the surface resistance value (Ω / □) of the obtained conductive film.

[0026]

[Table 4]

[Comparative Example] SnO ₂ having an average primary particle size of 60Å
The fine particles were ground in pure water for 4 hours with a sand mill. After this solution was deflocculated at 90 ° C. for 1 hour, a solution obtained by hydrolyzing ethyl silicate and adding 3% by weight of ethanol to SiO _{2 in} terms of SiO _{2 was} converted to SnO ₂ : SiO ₂ = 2: 1 by weight. The mixture was mixed in a ratio such that it was coated on the surface of a glass plate having a diameter of 70 mm by a spin coating method at a rotation speed of 750 rotations / minute for 5 seconds, and then heated at 380 ° C. for 30 minutes. The surface resistance value of the obtained film was 1 × 10 ⁸ (Ω / □).

[0028]

According to the present invention, an excellent 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. Especially, it can be applied to large area substrates such as panel face of CRT.
Since it can be mass-produced, its industrial value is very high.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number for FI Technical indication H01J 29/88 9057-5E (72) Inventor Keiko Kubota 1150 Hazawa-cho, Kanagawa-ku, Yokohama, Kanagawa Asahi Glass (72) Inventor Satoshi Takemiya 1150 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Asahi Glass Co., Ltd.

Claims (6)

[Claims] 1. A method for producing a conductive film containing rhenium oxide, which comprises applying a coating liquid containing a rhenium compound and another metal compound onto a substrate and then heating the coating liquid. 2. A metal compound other than a rhenium compound is heated to produce SiO ₂ , ZrO ₂ , TiO ₂ , and A, respectively.
a Si compound, a Zr compound, a Ti compound, which becomes l ₂ O ₃ ,
The method for producing a conductive film according to claim 1, wherein the conductive film is at least one of Al compounds. 3. A metal compound other than a rhenium compound is S
The method for producing a conductive film according to claim 2, wherein the conductive film is at least one selected from the group consisting of i, Zr, Ti, Al alkoxides, their hydrolysates, and salts. 4. A conductive film obtained by the manufacturing method according to claim 1. 5. A glass article having a conductive film formed on a glass substrate by the method according to claim 1. 6. A Braun tube having a conductive film formed on the surface of the Braun tube by the manufacturing method according to claim 1.