JPH09129141A - Metal oxide thin film forming coating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating agent which is easy to apply, and by which it is possible to form a dielectric protective film having an excellent transparency and film thickness as the panel characteristics of a plasma display panel by using both the coating agent composed of organic acid metal salt, solvent, a thickener and an organic substance, and a specified compound. SOLUTION: A coating agent for forming a metal oxide thin film contains an addition agent composed of the organic acid metal salts of alkaline earth metal and/or rare earth metal, solvent, a thickener and an organic substance, and a polyhydric alcohol derivative, organic acid of C1to6 , and amine are used together therewith. The coating agent is formed into a metal oxide thin film by an application heat decomposition method. As the organic acid metal salt, it is desirable that the single organic acid metal salt of Mg, Ba, or Sr, or mixture of two or more of them are used together with one or two or more of the organic acid metal salts of Ca or the rare earth metal.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a coating agent for forming a metal oxide thin film (hereinafter referred to as a coating agent) for forming a transparent dielectric protective film of a color plasma display panel by a coating pyrolysis method. Is.

[0002]

2. Description of the Related Art Conventionally, in an AC type plasma display panel (hereinafter referred to as PDP), protection of discharge electrodes,
In order to reduce the discharge start voltage and the discharge sustaining voltage, the electrodes are covered with a dielectric protective film made of an alkaline earth metal oxide.

Since the dielectric protective film of the full-color AC type surface discharge reflection type PDP is formed on the front glass, it is necessary to have particularly excellent transparency and electric characteristics. Therefore, the protective film is formed by the vapor deposition method, but it is expensive and requires complicated equipment, and the productivity is poor, so that there is an economical problem.

Therefore, there is no need for expensive and complicated equipment,
Moreover, there is a coating pyrolysis method as a method of forming a dielectric protective film in a simple process, and a specific example is a paste for forming a transparent film containing an alkaline earth metal compound soluble in an organic solvent (Japanese Patent Laid-Open No. SHO11-96, 58-135155),
A method for forming a dielectric protective layer (Japanese Patent Laid-Open No. Hei 6-162920), in which an organic compound containing an alkaline earth metal is applied to a dielectric and pyrolyzed to form a protective layer made of a metal oxide, and Mg or the like is applied to the dielectric layer. PDP coated with a metal alkoxide and thermally decomposed to cover a metal oxide protective film (Japanese Patent Laid-Open No. 6-2203).
72), alkali metal oxide particles, Al, S
A dielectric protective agent composed of a metal organic compound such as i, Ti, and Zr (JP-A-6-31667), a cathode of an AC type PDP, and a PDP in which a dielectric layer is covered with a metal oxide protective film (JP-A-6-31970). 7-14516) has been proposed.

[0005]

However, in the above-mentioned prior art, organic acid metal salt of alkaline earth metal,
Alternatively, when a metal alkoxide is used as a dielectric protective film precursor, it is possible to form a metal oxide thin film,
The thickness of the formed uniform and transparent film is 0.3 μm or less, and the film has poor adhesion to the dielectric. Moreover, the film thickness is set to 0.
If the thickness is 3 μm or more, a non-uniform and opaque film is formed, which is a practical problem.

An object of the present invention is to provide an organic metal acid metal salt for forming a metal oxide thin film on a dielectric by a coating pyrolysis method, and an additive composed of a solvent, a thickener and an organic substance for dissolving it. It is an object of the present invention to provide a coating agent that can be easily applied and has a practically desirable transparency and film thickness as a panel property of a PDP, which can form a dielectric protective film.

[0007]

In order to achieve the object, the present invention uses a polyhydric alcohol derivative together with other solvent as a solvent for dissolving an organic acid salt of an alkaline earth metal and / or a rare earth metal, and further Transparent MgO is prepared by using organic acids and amines of the formulas 1 to 6 together, using a thickener and a solvent, and adjusting the viscosity to a viscosity that is easy to apply by a method such as screen printing, spin coating, dipping, or spraying.
It can be used as a precursor of a thin film, and by coating and drying the coating agent, baking at 350 to 600 ° C.
As a panel property of the PDP, it was found that a dielectric protective film having practically desirable transparency and film thickness can be formed.

That is, the present invention is a coating agent for forming a metal oxide thin film, which comprises an organic acid metal salt of an alkaline earth metal and / or a rare earth metal, a solvent, a thickener and an additive made of an organic substance, A coating agent for forming a metal oxide thin film for forming a metal oxide thin film by a coating thermal decomposition method, which comprises using a polyhydric alcohol derivative, an organic acid having 1 to 6 carbon atoms and an amine together.

According to the present invention, the organic acid metal salt, the solvent, the thickener and the additive are organic substances, and these organic components are vaporized or thermally decomposed when the coating agent is applied and dried or baked. Dissipates into the atmosphere. Therefore, the coating agent is decomposed into a metal and an organic component by coating and drying and baking, and the subsequent oxidation by heating forms a transparent metal oxide thin film having a high light transmittance.

The solvent for dissolving the organic acid metal salt of alkaline earth metal and / or rare earth metal in the present invention into a solution is
Although not limited to these, for example, xylene, toluene, isopropyl alcohol, methyl isobutyl ketone, butyl acetate, butyl carbitol, mineral spirits, cyclohexane, cyclohexanone, and the like solvents can be used alone or in combination. However, the solution and thickener are combined to form a coating agent that is easy to apply.
Even if baked for 30 minutes, a transparent metal oxide thin film having good adhesion to the dielectric cannot be formed.

However, an organic acid metal salt of an alkaline earth metal and / or a rare earth metal is added to the polyhydric alcohol derivative of the present invention, such as butyl carbitol, carbitol, methyl carbitol, butyl cellosolve, cellosolve, methyl cellosolve, ethylene glycol. A solution of diethylene glycol or the like, alone or in combination of one or more, or in combination with another solvent, is added to a solution of 0.1 to 6 carbon atoms of an organic acid.
~ 30% (weight% in coating agent) and amine 0.1
After applying 10% (% by weight in the coating agent), and further adjusting the viscosity with a thickener to a viscosity that makes it easy to apply by a method such as screen printing, spin coating, dipping, or spraying, after applying it to the dielectric By thermally decomposing, it is possible to obtain a coating agent that has good adhesion to the dielectric and forms a uniform and transparent thin film. There is no limitation on the method of mixing the organic acid metal salt solution, the organic acid having 1 to 6 carbon atoms, the amine and the thickener, and it is sufficient to simply mix the necessary amounts in the process of preparing the coating agent.

In the present invention, one or more kinds of organic acid metal salts can be mixed and used. Particularly, one or more kinds of organic acid metal salts of Mg, Ba and Sr and Ca or rare earth metal are used. When one kind or a mixture of two or more kinds of organic acid metal salts is used, the physical strength of the metal oxide thin film mainly composed of Mg, Ba and Sr can be increased and the adhesion to the dielectric can be improved. .

The type of the organic acid forming the organic acid metal salt used in the coating agent of the present invention is not particularly limited as long as the formed organic acid metal salt can be dissolved in an organic solvent. For example, capron. Acid, caprylic acid, capric acid, octylic acid, secanoic acid, neodecanoic acid, neoheptanoic acid, neononanoic acid, N-heptanoic acid, naphthenic acid, tall oil fatty acid, etc. alone or in combination of two or more kinds of organic acid metal salts Those produced by reaction are preferable. However, an organic acid metal salt prepared by mixing an organic acid having 6 or less carbon atoms, such as acetic acid or propionic acid, with one having 7 or more carbon atoms can also be used. Further, an organic acid metal salt obtained by using an organic acid having an average carbon number of 6 or less as a starting material is difficult to use alone because it has poor solubility in a solvent, but is used within a range in which it is soluble in other organic acid metal salts. It doesn't matter.

As the solvent used in the present invention, a polyhydric alcohol derivative such as butyl carbitol, carbitol, methyl carbitol, butyl cellosolve, cellosolve, methyl cellosolve, ethylene glycol, diethylene glycol, etc., or a homogeneous mixture thereof can be used. There is no particular limitation as long as the organic acid metal salt can be dissolved, and it is preferable to use a plurality of solvents such as xylene, toluene, isopropyl alcohol, methyl isobutyl ketone, butyl acetate, butyl carbitol acetate, mineral spirits in combination. .

The organic acid having 1 to 6 carbon atoms used in the present invention has a smaller carbon number than the organic acid used for the organic acid metal salt such as formic acid, acetic acid, propionic acid, pentanoic acid, hexanoic acid, heptanoic acid and acrylic acid. It is preferable to use one type, and it is possible to use one type alone or a plurality of types in combination. It is desirable that the total amount used is in the range of 0.1 to 30% by weight, preferably 2 to 8% by weight, based on the coating agent. Further, instead of these organic acids, that is, organic acids having 1 to 6 carbon atoms, it is also possible to use them in the state of alkaline earth metal or rare earth metal salts of these organic acids. In that case, the amount used is preferably 0.1 to 30% by weight based on the coating agent, in terms of the organic component constituting the organic acid metal salt having 1 to 6 carbon atoms.

The amine used in the present invention is not limited to these as long as it reduces the surface tension of the organic acid metal salt solution, but allylamine, diallylamine, triallylamine, isopropylamine, diisopropylamine, Iminobispropylamine, ethylamine, diethylamine, triethylamine, 3-ethoxypropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine,
3-Methoxypropylamine and the like are preferable, and these amines can be used alone or in combination of two or more.

These amines are used for coating agents.
It can be used in the range of 0.1 to 20% by weight, but it is preferably used in the range of 2 to 5% by weight.

As the thickener made of an organic material used in the present invention, it is desirable to use ethyl cellulose, nitrocellulose, acrylic resin, butyral resin or the like as the thickener.

When the coating agent of the present invention is used as a paste for screen printing, one or a plurality of thickeners such as ethyl cellulose, nitrocellulose, acrylic resin and butyral resin are added to the organic acid metal salt solution. Add the required amount and dissolve, then butyl carbitol,
It is necessary to adjust the viscosity suitable for printing with a solvent such as terpineol or Texanol. In the case of spin coating or spray coating, it is possible to use the screen printing paste diluted with a solvent, but it is not necessary to use a particularly large amount of thickener, and the organic acid metal salt is simply diluted with the solvent. But it doesn't matter. Further, an antifoaming agent or a leveling agent can be used as necessary.

However, whichever coating method is used, if the total metal content in the coating agent is high, it is difficult to coat thinly and uniformly, so that a desired transparent and uniform metal oxide thin film is formed. Becomes difficult. On the other hand, if the total metal content in the coating agent is low, a uniform thin film can be formed, but 0.4-
The coating pyrolysis must be repeated several times to obtain a film thickness of 1.3 μm. Therefore, the total metal content in the coating agent is 5.0% by weight or less, preferably 2.0 to 5.0% by weight in the case of screen printing by adjusting the amount of solvent, thickener, etc. In this case, it should be 4.0% by weight or less, preferably 0.5 to 2.0% by weight.

The method for preparing the coating agent for forming a metal oxide thin film of the present invention is not particularly limited, and a solution prepared by previously dissolving a thickener in a solvent is added to an organic acid metal salt solution and dissolved.
It is preferable to adjust the viscosity with a diluting solvent. Although there is no limitation on the filtration method performed as necessary, pressure filtration is preferable, and it is not desirable to perform vacuum filtration for a long time.

[0022]

【Example】

Example 1 A sample was prepared by mixing each raw material in the order of numbers according to the formulation shown in Table 1, and the solution was mixed with an applicator of 75 μm to 70 μm.
It was applied on a glass plate of mm × 150 × 2, dried for 5 minutes with a hot air dryer at 100 ° C., and then baked for 5 minutes at 450 ° C. in an electric furnace. As a result, as shown in Table 1, a transparent metal oxide thin film could be formed on the glass surface. However, the comparative example did not form a film.

[0023]

[Table 1]

(Evaluation criteria) Film condition: ○ (transparent uniform film), Δ (slightly cloudy film), ×
(No film is formed) Film thickness: Measured with a stylus type film thickness meter (surface shape measuring instrument: manufactured by Nippon Vacuum Co., Ltd.). Transmittance: Measured with a spectrophotometer. (Note) (* 1) Mg octylate solution in which the Mg content is adjusted to 2% by weight with a mixed solvent of butyl carbitol and xylene (weight ratio 1: 1). (* 2) Butyl carbitol with ethyl cellulose (45
A liquid in which 7.5 wt% of cp) is dissolved.

Example 2 A mixture was prepared by mixing each raw material in the order of the numbers shown in Table 2 to prepare a sample.
It was applied on a glass plate of 0 mm × 150 × 2, dried for 5 minutes by a hot air dryer at 100 ° C., and then baked at 450 ° C. for 5 minutes in an electric furnace. As a result, as shown in Table 2, a transparent metal oxide thin film could be formed on the glass surface. However, the comparative example did not form a film.

[0026]

[Table 2]

(Evaluation Criteria) Film condition: ○ (transparent uniform film), Δ (slightly cloudy film), ×
(No film is formed) Film thickness: Measured with a stylus type film thickness meter (surface shape measuring instrument: manufactured by Nippon Vacuum Co., Ltd.). Transmittance: Measured with a spectrophotometer. (Note) (* 1) Organic acid Mg solution whose Mg content is adjusted to 2% by weight with a mixed solvent of butyl carbitol and xylene (weight ratio 1: 1). (* 2) Butyl carbitol with ethyl cellulose (45
A liquid in which 7.5 wt% of cp) is dissolved.

Example 3 A mixture was prepared by mixing each raw material in the order of the numbers shown in Table 3 to prepare a sample.
It was applied on a glass plate of 0 mm × 150 × 2, dried for 5 minutes by a hot air dryer at 100 ° C., and then baked at 450 ° C. for 5 minutes in an electric furnace. As a result, as shown in Table 3, a transparent metal oxide thin film could be formed on the glass surface.

[0029]

[Table 3]

(Evaluation Criteria) Film Condition: ◯ (Transparent uniform film). Film thickness: Measured with a stylus type film thickness meter (surface shape measuring instrument: manufactured by Nippon Vacuum Co., Ltd.). Transmittance: Measured with a spectrophotometer. (Note) (* 1) Organic acid Mg solution whose Mg content is adjusted to 2% by weight with a mixed solvent of butyl carbitol and xylene (weight ratio 1: 1). (* 2) Butyl carbitol with ethyl cellulose (45
A liquid in which 7.5 wt% of cp) is dissolved.

(Example 4) The ingredients shown in Table 4 were mixed in the order of numbers to prepare a screen printing paste.
It was printed on a 70 mm × 150 × 2 glass plate with a mesh (SUS), dried for 5 minutes by a hot air dryer at 100 ° C., and then baked at 450 ° C. for 5 minutes in an electric furnace. As a result, as shown in Table 4, a transparent metal oxide thin film could be formed on the glass surface. However, the comparative example did not form a film.

[0032]

[Table 4]

(Evaluation Criteria) Film condition: ○ (transparent uniform film), Δ (slightly cloudy film), ×
(No film is formed) Film thickness: Measured with a stylus type film thickness meter (surface shape measuring instrument: manufactured by Nippon Vacuum Co., Ltd.). Transmittance: Measured with a spectrophotometer. (Note) (* 1) Organic acid Mg solution whose Mg content is adjusted to 2% by weight with a mixed solvent of butyl carbitol and xylene (weight ratio 1: 1). (* 2) Butyl carbitol with ethyl cellulose (45
A liquid in which 7.5 wt% of cp) is dissolved.

(Example 4) According to the formulation of Table 5, raw materials were mixed in the order of numbers to prepare a sample, and the solution was applied onto a 70 mm x 150 x 2 glass plate with an applicator of 75 µm, and 1
After drying for 5 minutes in a hot air dryer at 00 ℃, 450 ℃ in an electric furnace
And baked for 5 minutes. As a result, as shown in Table 5, it was possible to form a transparent metal oxide thin film on the glass surface, which is not easily scratched.

[0035]

[Table 5]

(Evaluation Criteria) After the film formed by firing was cooled, the easiness of scratching when lightly rubbing with gauze was examined. ○: Good (no scratches). Δ: Slightly defective (easily scratched). Film condition: ○ (transparent uniform film). Film thickness: Measured with a stylus type film thickness meter (surface shape measuring instrument: manufactured by Nippon Vacuum Co., Ltd.). (Note) (* 1) Mg octylate solution in which the Mg content is adjusted to 2% by weight with a mixed solvent of butyl carbitol and xylene (weight ratio 1: 1). (* 2) Butyl carbitol with ethyl cellulose (45
A liquid in which 7.5 wt% of cp) is dissolved.

[0037]

The transparent MgO protective film of the dielectric of the surface discharge reflection type color PDP is conventionally formed by the vapor deposition method, but the productivity is poor and there is an economical problem. However, the coating material for forming a metal oxide thin film of the present invention is screen-printed or spray-coated on the dielectric of PDP, and after drying, 350 to 6
By baking at 00 ° C for 1 to 30 minutes, the film thickness becomes 0.1
It became possible to form a transparent metal oxide thin film of ˜1.3 μm. As a result, a significant economic effect can be expected.

Claims (2)

[Claims] 1. A coating agent for forming a metal oxide thin film, which comprises an organic acid metal salt of an alkaline earth metal and / or a rare earth metal, a solvent, a thickener, and an additive, and is a polyhydric alcohol. A coating agent for forming a metal oxide thin film for forming a metal oxide thin film by a coating thermal decomposition method, which comprises using a derivative, an organic acid having 1 to 6 carbon atoms and an amine together. 2. An organic acid metal salt of Mg, Ba, Sr alone or a mixture of two or more kinds of organic acid metal salts, and one or more kinds of organic acid metal salts of Ca or rare earth metals are used in combination. The coating agent for forming a metal oxide thin film according to claim 1, characterized in that: