JPH106431A - Manufacturing method of laminated film and laminated film - Google Patents

Abstract

(57) [Problem] To provide a functional film and its protective film by one firing, and to form a protective film that has excellent adhesion to the functional film and solves the problems of the prior art. To provide a method for manufacturing a laminated film. SOLUTION: In the method for forming a laminated film in which an inorganic functional film and its inorganic protective film are in close contact with each other, a coating liquid for forming an inorganic functional film is applied on a substrate and dried to form a film,
Then, a coating liquid for forming an inorganic protective film is applied and dried on the coating to form a coating, and thereafter, both the coatings are simultaneously subjected to heat treatment. Laminated film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated film and a laminated film, and more particularly to a method for producing a functional film used for electronic / electric parts and optical parts and a laminated film.

[0002]

2. Description of the Related Art Conventionally, so-called functional films such as tin oxide used for electronic and electric parts, iron oxide used for magnetic articles, and silicon dioxide and titanium dioxide used for optical members are mainly composed of metal oxides. Is formed.

For example, in the case of a plasma display panel, an electrode provided on a glass substrate is covered with a dielectric film, and a magnesium oxide film as a protective film is formed on the dielectric film. Films of magnesium oxide and other metal oxides are usually prepared by EB evaporation, sputtering, CVD, etc.
And the like, or a thick film method in which a dispersion of a metal oxide or a precursor thereof is applied to a substrate, dried and fired to form a metal oxide film.

[0004] The thin film method using a vacuum process generally has the disadvantage that the productivity is low and the obtained product is expensive, and it is extremely difficult to store a large substrate such as a plasma display panel substrate in a vacuum chamber. Assuming a large screen plasma display panel,
The thin film method using a vacuum process has problems in terms of equipment cost and productivity.

[0005] The coating method has been energetically studied because it is a simple method, but a protective film having satisfactory performance has not been formed yet. For example, in a plasma display panel, a film of a protective film forming material is formed on a dielectric film formed by firing, and a magnesium oxide film is formed by firing. Are insufficient, and cracks occur in the protective film during firing.
In addition, firing is performed for 1 time each when forming the dielectric film and when forming the protective film.
It has to be performed twice each time, so that the process is complicated, which is not only unfavorable from the viewpoint of energy saving, but also hinders continuous production of the display.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to form a functional film and its protective film by a single firing, and to form a functional film with a functional film. It is an object of the present invention to provide a method for producing a laminated film in which a protective film having excellent adhesion and a solution to the above-mentioned problems is formed.

[0007]

The above object is achieved by the present invention described below. That is, the present invention provides a method for forming a laminated film in which an inorganic functional film and its inorganic protective film are in close contact with each other, forming a coating by applying and drying a coating liquid for forming an inorganic functional film on a substrate, A coating method for forming an inorganic protective film is applied and dried on the coating to form a coating, and thereafter, both coatings are simultaneously subjected to heat treatment. It is a laminated film.

[0008]

Next, the present invention will be described in more detail based on embodiments. First, the functional film forming material and the protective film forming material used in the present invention will be described. As the coating liquid used to form the functional film, for example, when the functional film is a dielectric film, for example, low melting glass, alumina, titania, lead oxide, zirconia, zinc sulfide and the like An inorganic dielectric material is used, and in the case of another functional film, a material exhibiting each function is used. The preferred particle size of these functional inorganic particles is 0.01 to
1.0 μm, more preferably 0.05 to 0.5 μm
m.

The above-mentioned coating liquid is, for example, a paste obtained by mixing the above-mentioned functional material particles, a binder, a solvent, and the like, and a dispersion obtained by dispersing the above-mentioned functional material particles in an appropriate solvent ( (Sol solution) or the like, but it goes without saying that the form of use may be other than these.

In the following, the case where the functional film is a dielectric film will be described. However, the dielectric film described below is also used for other functional films, except that the functional material for expressing the function and the material for forming the protective film are different. This is the same as the case of forming the protective film.

The coating liquid for forming a protective film may contain only an alkaline earth metal compound or may contain inorganic composite particles obtained by coating functional material particles with fine particles of an alkaline earth metal compound. It may be something. In the former case, the preferred particle size of the alkaline earth metal compound particles is 0.01 to 1.0 μm, more preferably 0.1 to 1.0 μm.
05 to 0.5 μm. When the particle size is less than 0.01 μm, the formed protective film cannot exhibit a sufficient protective function. On the other hand, when the particle size exceeds 1.0 μm, the formed protective film has poor transparency and visibility. Will be damaged. A preferred alkaline earth metal is magnesium, and preferred magnesium compounds include, for example, inorganic compounds such as magnesium oxide, magnesium hydroxide, and magnesium carbonate; And organic magnesium compounds having a group. When using an organic magnesium compound having a hydrolyzable group as a dispersion of water or an organic solvent, use additives such as alkanolamines such as diethanolamine, carboxylic acids, and glycols that promote dispersion stability. Is preferred.

When the coating liquid for forming a protective film contains the inorganic composite particles, the particle size of the alkaline earth metal compound covering the inorganic particles is preferably 0.001 to 0.5 μm.
m, and more preferably 0.01 to 0.1 μm. When the particle size is less than 0.001 μm, since the fine particles of the alkaline earth metal compound form aggregates, it is extremely difficult to perform the coating treatment with the alkaline earth metal compound at the time of forming the composite particles, and uniform coating can be achieved. I can't get it. On the other hand, when the particle size exceeds 0.5 μm, the coating treatment of the inorganic particles with the alkaline earth metal compound cannot be performed efficiently.

The above-mentioned inorganic composite particles are obtained by a mechanical method using a powder mixer or the like; dispersing inorganic functional particles such as low-melting glass particles in a solution of an alkaline earth metal compound; A method of precipitating a derivative of an alkaline earth metal compound on a substrate; mixing fine particles of an inorganic functional material having a zeta potential of + and-and material particles for a protective film in a medium to form another particle on the surface of one particle; A method utilizing hetero-aggregation for aggregation (for example, the zeta potential of low-melting glass particles is -15.76 V, and the zeta potential of magnesium oxide is +30.18 V); protection with inorganic functional particles having mutually reactive groups A surface decoration method in which a coating made of a material for a protective film is formed on the surface of the inorganic functional particles by reacting with a material for a film (in a solution state) Dispersion liquid can be prepared by dissolving the organic alkaline earth metal compound is reacted) or the like having a hydrolyzable group.

Next, formation of a dielectric film and a protective film using each of the above coating solutions will be described. (1) Preparation of Dielectric Film Coating When, for example, a paste-like coating liquid is used for forming a dielectric film, the coating liquid is screen-printed on a base (for example, an electrode) and dried. As a result, a film for a dielectric film is formed. The thickness of the film after drying is usually 5 to 50 μm
It is about. When the coating liquid is a liquid such as a dispersion,
Conventional coating methods such as spray coating, dip coating, spin coating, roll coating, bar coating, meniscus coating, and curtain flow coating are used.

(2) Preparation of Protective Film Forming Film Next, a film is formed on the above dielectric film forming film using a coating liquid for forming a protective film of the dielectric film. The protective film forming film is formed on the dielectric film forming film formed in the above (1). The method of forming the coating is exactly the same as in the case of (1). The thickness of the coating after drying is usually 0.01 to 1
It is about 0 μm.

In the present invention, when a coating film for forming a protective film is applied on the coating film for forming a dielectric film before baking to form a coating film, the coating liquid for forming a protective film is used for forming the dielectric film. The protective film-forming material penetrates into the film-forming film through the gap, and after sintering, the protective film-forming material is buried in the dielectric film, or the protective film-forming coating liquid aggregates on the dielectric film-forming film. That a uniform coating cannot be obtained.

In such a case, by forming a layer of a polymer material on the film for forming a dielectric film and then forming a film composed of a coating solution for forming a protective film, a uniform film free of the above-mentioned problems can be obtained. A protective film for forming a protective film can be formed. The polymer material used for the above purpose is not particularly limited,
Materials that are preferably water-soluble or water-dispersible, are completely decomposed by baking, and do not leave organic matter in the film, such as celluloses, acrylic resins, and acetal resins, are preferred materials. The polymer material is applied as a solution or a dispersion on the dielectric film forming film by the above-mentioned application method, and dried. The thickness of the film is not particularly limited as long as the above problem is prevented, and is usually about 0.01 to 10 μm.

(3) Formation of Dielectric Film and Protective Film Thereof The substrate on which the dielectric film-forming film and the protective film-forming film are deposited on the substrate in (1) and (2) above is subjected to heat treatment ( By firing, a laminated film in which a dielectric film having a predetermined thickness and a protective film thereof are in close contact with each other is simultaneously formed. The firing is performed at the higher of the dielectric film forming temperature and the protective film forming temperature. In this case, the heat treatment is performed at the temperature and time for forming a normal dielectric film. For example, 400-6
It is about 1 to 4 hours at 00 ° C.

As described above, a laminated film in which the dielectric film and its protective film are laminated on the substrate is formed. Further, by forming a protective film forming film on the functional film forming film and performing a heat treatment at the same time, an intermediate layer in which the functional film forming material and the protective film forming material are mixed is partially formed. Therefore, the adhesion between the functional film and the protective film is sufficient, and the film strength of the protective film is sufficiently improved. In the case of an inorganic functional film other than a dielectric film, except that the above-mentioned dielectric material-forming inorganic material and its protective film-forming inorganic material are changed to a target functional film-forming inorganic material and its protective film-forming inorganic material. A laminated film of a functional film and its protective film is formed in the same manner as described above.

[0020]

Next, the present invention will be described more specifically with reference to examples. Parts and percentages in the text are based on weight unless otherwise specified.

Example 1 Preparation of a coating solution for forming a protective film of a dielectric film Magnesium oxide (UBE Kosan, UBE
2000A) was dispersed to prepare a 2% concentration magnesium oxide dispersion.

A paste prepared by dispersing a low-melting point gatas in an aqueous solution of hydroxypropylmethylcellulose as a coating liquid for forming a dielectric film was coated on a glass substrate so as to have a dry film thickness of 20 μm.

Next, the above-mentioned coating liquid for forming a protective film is coated on the above-mentioned coating film for forming a dielectric film by dip coating so as to have a dry film thickness of about 0.2 μm, and a lifting speed of 4 mm. / Sec and dried at 120 ° C. for 0.5 hour. Thereafter, baking was performed at 580 ° C. for 2 hours. The total thickness of the dielectric film 5 and the protective film 6 thus formed was 15 μm.

Embodiment 2  1% concentration on the dielectric film forming film in Example 1.
Dip hydroxypropyl methylcellulose aqueous solution
After applying by the coating method and drying at 120 ° C for 30 minutes
Then, a coating film for forming a protective film was formed in the same manner as in Example 1.
Except for making the laminated film of the present invention the same as in Example 1,
Produced. FIG. 1 shows a schematic diagram of this production method.

Example 3 Preparation of Coating Liquid for Forming Protective Film for Dielectric Film A liquid (1% solid content) in which low-melting glass powder (particle diameter: 2 to 3 μm) was dispersed in special grade ethanol. In 27 parts, 14.27 parts of magnesium acetate tetrahydrate was dissolved. This solution was refluxed at 80 ° C. for 1 hour to precipitate a magnesium compound on the surface of the lead oxide powder. The powder was separated from this solution by filtration and dried at room temperature for 12 hours. One part of the obtained powder (inorganic composite particles) was dispersed in 49 parts of a 0.25% aqueous solution of hydroxypropylmethylcellulose to obtain a coating liquid for forming a protective film of a dielectric film.

A laminated film of the present invention was prepared in the same manner as in Example 1 except that the above-mentioned coating solution was used as a coating solution for forming a protective film for a dielectric film. FIG. 2 shows a schematic diagram of this production method.

[0027]

According to the present invention described above, a dielectric film and its protective film can be formed in one firing step.
It is possible to reduce the manufacturing cost of a plasma display panel and the like and save energy. Further, by forming a protective film forming film on the functional film forming film and performing a heat treatment at the same time, an intermediate layer in which the functional film forming material and the protective film forming material are mixed is partially formed. Therefore, the adhesion between the functional film and the protective film is sufficient, and the film strength of the protective film is sufficiently improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of forming a laminated film.

FIG. 2 is a schematic view showing an example of forming a laminated film.

Claims (8)

[Claims] In a method for forming a laminated film in which an inorganic functional film and an inorganic protective film thereof are in close contact with each other, a coating liquid for forming an inorganic functional film is applied on a substrate and dried to form a film.
Next, a coating liquid for forming an inorganic protective film is applied and dried on the coating to form a coating, and then both the coatings are heat-treated simultaneously. 2. The method according to claim 1, wherein a layer made of a polymer material is interposed between the inorganic functional film before the heat treatment and the inorganic protective film, and the layers are simultaneously heat-treated. 3. The method according to claim 1, wherein the inorganic functional film is an inorganic dielectric film. 4. The method according to claim 1, wherein the coating liquid for forming an inorganic protective film contains an alkaline earth metal compound. 5. The alkaline earth metal compound is at least one compound selected from an alkaline earth metal oxide, hydroxide, carbonate, and organic alkaline earth metal compound having a hydrolyzable group. A method for manufacturing a laminated film according to claim 4. 6. The method according to claim 5, wherein the alkaline earth metal compound is used in a state of being coated with the inorganic functional particles. 7. The method for producing a laminated film according to claim 4, wherein the alkaline earth metal is magnesium. 8. A laminated film formed by the method according to claim 1. Description: