JP2002105358A - Inorganic film-forming coating agent, method for forming inorganic film using the same, and inorganic film-coated aluminum material and inorganic film-coated steel material each obtained using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inorganic film-forming coating agent capable of forming inorganic film with high corrosionproofness to metal in particular. SOLUTION: This inorganic film-forming coating agent is characterized by being obtained by reaction between (A) at least one fluoride selected from silicofluoric acid, titanofluoric acid and zirconofluoric acid and (B) at least one hydrolyzable monomer and/or oligocondensate selected from silicon monomer, titanium monomer and zirconium monomer each wholly substituted with hydrolyzable groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a coating agent for forming an inorganic film which forms an inorganic film excellent in corrosion resistance of a metal, a method of applying and drying the same to form an inorganic film, and an aluminum material coated with the inorganic film, The present invention relates to a steel material coated with an inorganic film.

[0002]

2. Description of the Related Art As a fin substrate for a heat exchanger of an air conditioner, a material obtained by subjecting aluminum or an aluminum alloy, which is excellent in light weight, workability, and heat conductivity, to a chemical conversion treatment is generally used. .

In a heat exchanger of an air conditioner, condensed water generated during cooling becomes water droplets to form a water bridge between the fins, and the ventilation passage is narrowed to increase the ventilation resistance, resulting in loss of power and noise. There is a problem that problems such as generation and scattering of water droplets occur. As a measure to prevent such a phenomenon, for example, the surface of an aluminum fin material (hereinafter, referred to as a “fin material”) is subjected to a hydrophilic treatment to prevent water droplets and the formation of bridges due to the water droplets.

[0004] However, the fin material on which the hydrophilized coating film obtained by these methods is formed, if the fin material is placed in a strong corrosive environment because the coating film has hydrophilicity,
There was a problem that it would be corroded in a few months.

[0005] To solve this problem, corrosion resistance,
From the viewpoint of cost and the like, there are many methods of performing a chromate treatment on the surface of an aluminum or aluminum alloy material as a base material. However, the chromate treatment has a problem in terms of environmental protection because chromium ions are harmful metal ions.

[0006] The undercoating agent and treatment method not using chromium ions are also known, for example, an acidic solution containing a titanium salt (zirconium salt), hydrogen peroxide and (condensed) phosphoric acid (derivative). Aluminum surface treatment method (JP-A-54-24232), treating aluminum with an alkaline aqueous solution containing titanium ions (zirconium ions, iron ions) and a complexing agent;
An aluminum surface treatment method of washing with water and treating with an aqueous acidic solution such as phosphoric acid (Japanese Patent Application Laid-Open No. 54-160527), and an aluminum surface treatment composition containing a phosphate ion, a titanium compound, a fluoride and an accelerator (Japanese Patent Application Laid-Open No. No. 20984), an aluminum-based metal surface treatment composition containing (condensed) phosphoric acid (salt), titanium salt (zirconium salt), fluoride, and (next) phosphorous acid (salt) 143
No. 752).

However, the surface treatment agent and the treatment method using the above-mentioned titanium compound have insufficient stability of the surface treatment agent, insufficient corrosion resistance as compared with chromate treatment, insufficient hydrophilicity, There were problems such as insufficient durability. Further, in recent years, excellent corrosion resistance is required for rust-proof coated steel sheets, and surface-treated steel sheets using zinc-based plated steel sheets as substrates in place of conventional cold-rolled steel sheets are often used.

Conventionally, chromate treatment and zinc phosphate treatment have been generally performed as surface treatments for galvanized steel sheets, but the toxicity of chromium is a problem. The chromate treatment has a problem of volatilization of chromate fume in the treatment process, a large cost for wastewater treatment equipment, and a problem of elution of chromate from the chemical conversion coating. Hexavalent chromium compounds are available from IARC (International
l Agency for Researchon Cancer Review) and many other public institutions have designated it as a carcinogen for the human body, and it is extremely harmful.

In the zinc phosphate treatment, after the zinc phosphate treatment, rinsing treatment with chromic acid is usually performed, so there is a problem of chromium treatment, and a reaction accelerator in the zinc phosphate treatment agent, and waste water such as metal ions. There is a problem of sludge treatment due to elution of metal ions from the treated and treated metal.

As a treatment method other than the chromate treatment and the zinc phosphate treatment, (1) a surface treatment method of treating with an aqueous solution containing aluminum biphosphate and then heating at a temperature of 150 to 550 ° C. -28857), (2)
A method of treating with an aqueous solution containing tannic acid (JP-A-51
And (3) a treatment method using sodium nitrite, sodium borate, imidazole, an aromatic carboxylic acid, a surfactant, or a combination thereof.

However, in the method (1), when a paint is applied thereon, the adhesion of the paint is not sufficient, and in the method (2), the corrosion resistance is inferior. In the method (3),
All have the problem that the corrosion resistance when exposed to a hot and humid atmosphere is poor.

Further, as a zinc-based steel sheet having a thin film having a thickness of several μm or less, JP-A-58-224174 and JP-A-
JP-A-60-50179 and JP-A-60-50180 disclose a method in which a zinc-based plated steel sheet is used as a base material, a chromate film is formed thereon, and an organic composite silicate film is further formed thereon as an uppermost layer. Rusted steel sheets are known, and have excellent performance in workability and corrosion resistance. However,
Since this rust-preventive steel sheet has a chromate film, there is a problem of safety and health due to chromate ions as described above. Further, the steel sheet obtained by removing the chromate film from the rust-proof steel sheet still has insufficient corrosion resistance. SUMMARY OF THE INVENTION An object of the present invention is to provide a coating agent for forming an inorganic film which forms an inorganic film which is particularly excellent in anticorrosiveness of a metal, and a method for forming an inorganic film by coating and drying it.

Another object of the present invention is to provide an inorganic material coated with an inorganic film which is excellent in corrosion resistance and which is suitable for a chromium-free undercoating film, particularly a heat exchanger aluminum fin material.

It is a further object of the present invention to provide a steel material coated with an inorganic film exhibiting excellent corrosion resistance even if the zinc-coated steel sheet does not have a chromate film.

[0015]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a coating agent for forming an inorganic film formed by reacting a specific fluoride with a specific hydrolyzable monomer and / or a low condensate thereof. Finds that it solves the traditional problems,
The present invention has been completed.

Thus, according to the present invention, the following components (A) at least one fluoride selected from hydrofluorosilicic acid, titanium hydrofluoric acid and zirconium hydrofluoric acid, and (B) all of which are hydrolyzed A coating material for forming an inorganic film, characterized by reacting at least one hydrolyzable monomer selected from a silicon monomer, a titanium monomer and a zirconium monomer substituted by a decomposable group and / or a low-condensate thereof. Is provided.

The present invention also provides a method for forming an inorganic film, which comprises applying the above-mentioned coating material for forming an inorganic film to a substrate and subjecting it to a heat treatment if necessary. The present invention also provides an aluminum material coated with an inorganic film, wherein an inorganic film formed from the above-mentioned coating material for forming an inorganic film is formed on the surface of an aluminum material or an aluminum alloy material.

Further, the present invention provides an inorganic film-coated steel material characterized in that the surface of the steel material is coated with an inorganic film formed from the above-mentioned coating material for forming an inorganic film.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION First, a coating agent for forming an inorganic film of the present invention will be described.

The coating agent for forming an inorganic film according to the present invention comprises (A) at least one fluoride selected from the group consisting of hydrofluoric silicic acid, titanium hydrofluoric acid, and zirconium hydrofluoric acid (hereinafter referred to as “hydrofluoric acid”).
This is sometimes abbreviated simply as “fluoride (A)”. ), And (B) at least one hydrolyzable monomer selected from silicon monomers, titanium monomers, and zirconium monomers, all of which are substituted with hydrolyzable groups, and / or low-condensates thereof (hereinafter, these are referred to as (Hereinafter sometimes simply referred to as "hydrolyzable compound (B)").

The fluoride (A) is hydrofluorosilicic acid, titanium hydrofluoric acid, or zirconium hydrofluoric acid;
H ₂ MF ₆ (M represents the same meaning as described above).

The hydrolyzable monomer used for the reaction with the above-mentioned fluoride (A) is one in which all hydrolyzable groups are directly bonded to silicon, titanium and zirconium atoms. The hydrolyzable group is a functional group that generates a hydroxyl group by a hydrolysis reaction. The hydrolyzable group is not particularly limited as long as it is conventionally known, but a lower alkoxyl group is particularly preferred from the viewpoint of excellent hydrolyzability and non-coloring.

As the hydrolyzable monomer, a compound represented by the general formula M (OR) ₄ (wherein M is a silicon atom, a titanium atom or a zirconium atom, and R is the same or different and is an alkyl group having 1 to 4 carbon atoms) Are preferred. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, and a tert-butyl group. No.

Specific examples of the hydrolyzable monomer include, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysisilane, trimethoxyethoxysilane, dimethoxydiethoxysilane, triethoxymethoxysilane, tetraethoxysilane, Methoxytitanium, tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium, trimethoxyethoxytitanium, dimethoxydiethoxytitanium, triethoxymethoxytitanium, tetramethoxyzirconium, tetraethoxyzirconium, tetrapropoxyzirconium, tetrabutoxysidirconium, trimethoxy Suitable examples include ethoxyzirconium, dimethoxydiethoxyzirconium, and triethoxymethoxyzirconium.

The low-condensation product of the hydrolyzable monomer includes
A low condensate obtained by hydrolyzing the above hydrolyzable monomers with each other and subjecting them to a condensation reaction can be used. The degree of condensation of the low condensate is preferably 2 to 30, particularly preferably 2 to 10. The hydrolysis-condensation reaction can be carried out by a conventionally known method, for example, by reacting a hydrolyzable monomer at room temperature or by heating in the presence of water and a catalyst (eg, a basic catalyst, an acidic catalyst, etc.). The above reaction is carried out, if necessary, for example, with methanol,
It can be carried out in a hydrophilic solvent such as ethanol, isopropyl alcohol, ethylene glycol or propylene glycol.

The ratio of the reaction between the fluoride (A) and the hydrolyzable compound (B) is preferably 0.1 to 10 weight ratio of the hydrolyzable compound (B) to 1 fluoride (A). Is desirably reacted in the range of 0.5 to 10 weight ratio. When the amount of the hydrolyzable compound (B) is less than 0.1, the film-forming property is reduced and the corrosion resistance is poor. On the other hand, when the amount of the hydrolyzable compound (B) is more than 10, the ratio of fluoride is reduced and the corrosion resistance is poor. It is not preferable. The reaction between the fluoride (A) and the hydrolyzable compound (B) is carried out at a reaction temperature of 1 to 70.
C., preferably within a range of 5 to 70 ° C. for 5 minutes to 20 hours, preferably 5 minutes to 10 hours.

[0027] The coating material for forming an inorganic film of the present invention produced by the reaction between the fluoride (A) and the hydrolyzable compound (B) provides a reaction between the fluoride (A) and the hydrolyzable compound (B). And a mixture of fluoride (A) and hydrolyzable compound (B). The structure of the reaction product of the fluoride (A) and the hydrolyzable compound (B) is not clear, but the fluoride (A) and the hydrolyzable compound (B) are linear or branched.
Or, it is considered that these structures are combined. The molecular terminal may be a fluoride (A) reaction component or a hydrolyzable compound (B) reaction component.

The reactant contains a MOR (H) group and an MF group. After coating the inorganic film-forming coating material of the present invention having the reactant, the reactant is dried or baked. Accordingly, it is considered that the MOR (H) group and the MF group do not substantially remain and a complete inorganic film is formed.

The coating material for forming an inorganic film of the present invention may be, if necessary, for example, methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol.
-Can be used after diluting with a hydrophilic solvent such as

The coating material for forming an inorganic film of the present invention may contain, if necessary, for example, a surfactant, a bactericide, and a rust inhibitor (tannic acid, phytic acid,
Benzotriazole), pigments such as coloring pigments, extender pigments, rust-preventive pigments, and the like.

The coating material for forming an inorganic film according to the present invention is usually used in an amount of 0.01 to 10% by weight, particularly 0.1 to 5% by weight, as a coating solid content.
% By weight is preferred. When the solid content is less than 0.01% by weight, the film-forming property becomes insufficient and the corrosion resistance is poor. On the other hand, when the solid content is more than 10% by weight, the film is cracked and the corrosion resistance is poor, which is not preferable.

The coating agent for forming an inorganic film of the present invention becomes a stable liquid in an acidic region, and particularly has a pH of 0.5 to 5, particularly 0.5 to 0.5.
The range of ~ 3 is preferred. The coating material for forming an inorganic film of the present invention can be applied to a base material and, if necessary, heat-treated to form an inorganic film.

Examples of the substrate include, but are not limited to, polyvinyl chloride resin, polyethylene terephthalate, acrylic resin, silicone resin, polyester resin, fluorine resin, epoxy resin, polyethylene resin, nylon resin, Butyral resin, cellulosic resin, phenolic resin, and resin in which two or more of these resins are combined, plastic substrate with surface treatment or primer, inorganic substrate such as glass, cement, paper, fiber, etc. Pulp base material, steel, aluminum, copper, stainless steel,
Examples include zinc, tin, a combination of two or more of these metals, and a metal substrate to which a surface treatment or a primer has been applied.

In the coating material for forming an inorganic film of the present invention, the coating material is applied to an aluminum material or an aluminum alloy material, and is applied to an aluminum material coated with an inorganic film, a steel material, or a phosphate-treated film surface of a metal surface. The steel material coated with an inorganic film obtained as described above will be described below.

Inorganic film-coated aluminum material: An inorganic film can be formed by applying the inorganic film-forming coating agent of the present invention on an aluminum material and drying. The coating material for forming an inorganic film is coated on a base material of an aluminum material (for example, an aluminum fin material or the like assembled on a heat exchanger) by a known coating method, for example, dipping. Painting, shower painting, spray painting,
It can be applied by roll coating, electrodeposition coating, or the like. As for the drying condition of the coating material for forming an inorganic film, it is usually preferable to dry the coating material at a maximum temperature of about 60 to 250 ° C. for about 2 seconds to about 30 minutes.

The dry thickness of the coating material for forming an inorganic film is usually 0.001 to 10 μm, especially 0.1 to 3 μm.
Is preferable. When the thickness is less than 0.001 μm, the performance such as corrosion resistance and water resistance is poor. On the other hand, when the thickness is more than 10 μm, the inorganic film is broken or the hydrophilicity is poor, which is not preferable.

Inorganic film-coated steel material: An inorganic film-forming coating material can be formed by applying the inorganic film-forming coating material of the present invention on the surface of the following steel material and drying it. The coating agent for forming an inorganic film is applied on the following steel material (for example, it may be assembled) by a coating method known per se, for example, dip coating, shower coating, spray coating, roll coating, electrodeposition coating It can be painted by such as. As for the drying condition of the coating material for forming an inorganic film, it is usually preferable to dry the coating material at a maximum temperature of about 60 to 250 ° C. for about 2 seconds to about 30 minutes.

The dry film thickness of the coating material for forming an inorganic film is usually from 0.001 to 10 μm, especially from 0.1 to 3 μm.
Is preferable. When the thickness is less than 0.001 μm, the performance such as corrosion resistance and water resistance is poor. On the other hand, when the thickness is more than 10 μm, the inorganic film is broken or the hydrophilicity is poor, which is not preferable.

As the steel material, preferably, hot-dip galvanized steel sheet, electro-galvanized steel sheet, iron-zinc alloy-coated steel sheet,
Examples thereof include a nickel-zinc alloy-plated steel sheet and an aluminum-zinc alloy-plated steel sheet (for example, an alloy-plated steel sheet sold under the trade names "Galvalume" and "Galphan"). Further, as the zinc-based plated steel sheet, a zinc-based plated steel sheet which has been subjected to a chemical conversion treatment such as a chromate treatment, a zinc phosphate treatment, and a composite oxide film treatment can also be used.

The steel material coated with an inorganic film is excellent in corrosion resistance, fingerprint resistance and the like, and can be used as it is as a rust-preventive steel plate or a lubricating rust-preventive steel plate, but an upper layer coating can be further formed thereon. The composition for forming this upper layer coating is:
Various coating compositions may be used, which may be appropriately selected according to the purpose. Examples of the coating composition include a primer coating and a colored top coating. A primer paint may be applied, and a colored top coat may be further applied thereon.

[0041]

In the present invention, an inorganic film-forming coating agent having the above-described structure is applied to a metal substrate such as aluminum or an electrogalvanized steel plate and heated to form an inorganic film. The fluoride (A) component constituting the coating agent for forming a film acts as a metal corrosion inhibitor,
On the other hand, the hydrolyzable compound (B) forms a metal oxide film such as silicon oxide, titanium oxide, or zirconium oxide or a silicon oxide film, so that an inorganic film having low oxygen permeability is formed, so that the anticorrosion property is excellent. (A) component and (B) component are chemically bonded to each other, so that the fluoride (A) component coordinated to the metal material acts as an inhibitor of metal corrosion. B) It is presumed that an inorganic film having high corrosion resistance and high durability was formed to be protected by the constituent metal oxide film or silicon oxide film.

[0042]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. Hereinafter, “parts” and “%” mean “parts by weight” and “% by weight”, respectively. The present invention is not limited to the following examples.

Production Example of Inorganic Film Forming Coating Agent (1) A mixture of 2.0 parts of tetra-iso-propoxytitanium and 48 parts of ethanol was mixed with 1.5 parts of 40% titanium hydrofluoric acid and 48.5 parts of deionized water. Was added dropwise with stirring at 20 ° C. for 1 hour. A cloudy inorganic film forming coating agent (1) was obtained.

Production Example of Inorganic Film-Forming Coating Agent (2) A white turbid inorganic film-forming coating agent (Tetra n-butoxytitanium) was used in place of tetraiso-propoxytitanium of Production Example 1 under the same manufacturing conditions. 2) was obtained.

Production Example of Inorganic Film Forming Coating Agent (3) Coating for forming a cloudy inorganic film under the same production conditions using 40% zirconium hydrofluoric acid instead of titanium hydrofluoric acid of Production Example 1. Agent (3) was obtained.

Production Example of Inorganic Film Forming Coating Agent (4) Coating for forming a cloudy inorganic film under similar production conditions using 40% hydrofluoric acid instead of titanium hydrofluoric acid of Production Example 1. Agent (3) was obtained. Production Example of Inorganic Film Forming Coating Agent (5) In the production example of the titanium treating agent (1), a transparent inorganic film forming coating agent (40% titanium hydrofluoric acid) was used under the same production conditions using 6 parts. 5) was obtained.

Preparation Example of Inorganic Film Forming Coating Agent (6) Preparation Example A mixture of 2.0 parts of tetra-iso-propoxytitanium and 48 parts of ethanol was added to a mixture of 50 parts of deionized water at 20 ° C.
For 1 hour with stirring. A cloudy inorganic film forming coating agent (6) was obtained.

Preparation Example of Inorganic Film Forming Coating Agent (7) A mixture of 40% titanium hydrofluoric acid (6 parts) and deionized water (94 parts) was mixed to obtain a transparent inorganic film forming coating agent (7).

Production Example of Inorganic Film-Forming Coating Agent (8) 6 parts of 40% zirconia hydrofluoric acid and 94 parts of deionized water were mixed to obtain a transparent inorganic film-forming coating agent (8).

Coatings (1) to (5) for forming inorganic film (Example) and coatings (6) to (8) for forming inorganic film (Comparative Example) were obtained.

Preparation of Test Plate A: An aluminum plate (A1050) having a thickness of 0.1 mm was replaced with an alkaline degreasing agent (trade name “Chem Cleaner 56, manufactured by Nippon CB Chemical Co., Ltd.).
1B ") using a 2% aqueous solution of
After washing with water, the undercoating agents obtained in the above Examples and Comparative Examples were applied so that the dry film weight was 0.2 g / m ^2, and baked for 20 seconds so that the material reached temperature was 100 ° C. A treated film was formed.

Each of the test coated plates was subjected to a corrosion resistance test. The test results are shown in Table 1 below. The test was performed according to the following test method.

Corrosion resistance: According to JIS-Z-2371 salt spray test method. The test time was set in three stages of 120 hours, 240 hours and 360 hours, and evaluated according to the following criteria. …: No white rust or swelling was observed on the coated surface.…: Little white rust or swelling was generated. ×: White rust or swelling was remarkably generated.

Preparation of Test Plate B: An electrogalvanized steel plate having a plate thickness of 0.6 mm and a coating adhesion amount of 20 g / m ^{2 on} one side was prepared.
After degreasing and washing with a 2% concentration aqueous solution in which an alkali degreasing agent (trade name “Chem Cleaner 561B” manufactured by CB Chemical Co., Ltd.) is dissolved, the base treating agent obtained in the above Examples and Comparative Examples With a dry film weight of 1.0 g / m ²
And baked for 20 seconds so that the temperature at which the material reached reached 100 ° C. to form an undercoating film. A corrosion resistance test was performed on each of the obtained test coated plates. The test results are shown in Table 2 below. The test was performed according to the following test method.

Corrosion resistance: A salt spray test specified in JISZ2371 was performed for up to 72 hours on a test-coated plate in which the end surface and the back surface of the test-coated plate were sealed.
The degree of rust on the coating film surface over time was evaluated according to the following criteria. a: no white rust is observed; b: white rust is less than 5% of the coating area; c: white rust is 5% or more and less than 10% of the coating area; d: white The degree of rust generation is 10% or more and less than 50% of the area of the coating film. E: The degree of white rust generation is 50% or more of the area of the coating film.

Preparation of Test Plate C An electrogalvanized steel plate having a thickness of 0.6 mm and a coating weight of 20 g / m ^{2 on} one side was used as a substrate. After the surface of the plated steel sheet is alkali-degreased, the surface is adjusted (spray treatment using “Preparen Z” manufactured by Nippon Parkerizing Co., Ltd.), and further treated with zinc phosphate (“Palbond 3308 manufactured by Nippon Parkerizing Co., Ltd.”). ), Washed with water and dried to obtain various types of plated steel sheets that have been subjected to a zinc phosphate treatment. The adhesion amount of the zinc phosphate treated film was 1.5 g / m ² .

The surface treating agents obtained in the above Examples and Comparative Examples were applied to the surfaces of the various types of plated steel sheets subjected to the zinc phosphate treatment so that the dry film weight was 1.0 g / m ² , The substrate was baked at 100 ° C. for 20 seconds to form an undercoating film. A corrosion resistance test was performed on each of the obtained test coated plates. The test results are shown in Table 3 below. The test was performed according to the following test method.

Corrosion resistance: A salt spray test specified in JISZ2371 was performed for up to 72 hours on the test coated plate in which the end face and the back face of the test coated plate were sealed.
The degree of rust on the coating film surface over time was evaluated according to the following criteria. a: no white rust is observed; b: white rust is less than 5% of the coating area; c: white rust is 5% or more and less than 10% of the coating area; d: white The degree of rust generation is 10% or more and less than 50% of the area of the coating film. E: The degree of white rust generation is 50% or more of the area of the coating film. The test results are shown below. Table 1

[0059]

[Table 1] Table 2

[0060]

[Table 2] Table 3

[0061]

[Table 3]

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J038 AA011 DL021 DM001 HA231 HA236 HA431 HA436 NA03 PB05 PC02 4K026 AA02 AA07 AA09 AA12 AA13 BA01 BA04 BA12 BB02 BB08 CA13 CA28 CA37 DA02 DA16 EA08 EB11

Claims (10)

[Claims] 1. The following components (A) at least one fluoride selected from hydrofluorosilicic acid, titanium hydrofluoric acid and zirconium hydrofluoric acid, and (B) all substituted by a hydrolyzable group A coating agent for forming an inorganic film, characterized by reacting at least one hydrolyzable monomer selected from a silicon monomer, a titanium monomer and a zirconium monomer and / or a low condensate thereof. 2. The method according to claim 1, wherein the hydrolyzable monomer has a general formula:
(OR) _{4 wherein} M is a silicon atom, a titanium atom or a zirconium atom, and R is the same or different and represents an alkyl group having 1 to 4 carbon atoms. Coating agent for inorganic film formation. 3. The coating material for forming an inorganic film according to claim 1, wherein the low-condensate has a degree of condensation of 2 to 30. 4. The reaction ratio between the fluoride (A) and the hydrolyzable monomer and / or the low-condensate thereof (B) is such that the ratio of the hydrolyzable monomer and / or the low hydrolyzable monomer to the fluoride (A) is one. The coating material for forming an inorganic film according to any one of claims 1 to 3, wherein the condensate (B) is reacted in a range of 0.1 to 10 weight ratio. 5. An inorganic film forming method, comprising applying the coating material for forming an inorganic film according to any one of claims 1 to 3 to a substrate and subjecting it to a heat treatment if necessary. Method. 6. An inorganic material, wherein the coating material for forming an inorganic film according to any one of claims 1 to 3 is applied to a metal base material and, if necessary, heat-treated to form the inorganic material. Film formation method. 7. An inorganic film formed from the coating material for forming an inorganic film according to claim 1 on the surface of an aluminum material or an aluminum alloy material. Aluminum material coated with inorganic film. 8. The aluminum material coated with an inorganic film according to claim 7, wherein the thickness of the inorganic film is 0.001 to 10 μm. 9. The steel material according to claim 1, wherein
An inorganic film-coated steel material characterized by being coated with an inorganic film formed from the coating material for forming an inorganic film according to item 6. 10. The inorganic film has a thickness of 0.001 to 10 μm.
The inorganic film-coated steel material according to claim 9 or 10, wherein: