JP2000290591A - Preparation of inorganic coating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form inorganic films excellent in hot-water resistance, alkali resistance and the like only by heating at relatively low temperatures by hydrolyzing a silicon-containing alkoxide compound in a water-organic solvent mixed solvent, followed by hydrolysis/polycondensation in the presence of a specific complex compound. SOLUTION: A silicon-containing alkoxide compound selected from tetraalkoxysilanes of the formula Si(OR)4 and oligomers thereof is hydrolyzed for one hour-one week at room temperature-95 deg.C in a mixed solvent comprising 5-80 wt.% of water of pH5 or less and an organic solvent. Then, at least one complex compound selected from Zr-, Al- and Ti-complexes is added thereto, and the resultant mixture, adjusted to pH5 or less, is subjected to hydrolysis/ polycondensation for 30 min.-one week at room temperature-95 deg.C to obtain an inorganic coating agent. The inorganic coating agent is blended with metallic oxide particles having an average particle diameter of 1-30 nm as occasion demands. in the formula, R is a 1-4C alkyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an inorganic coating agent, an inorganic coating agent, a method for producing an inorganic film, and an article having an inorganic film.

[0002]

2. Description of the Related Art Inorganic coating films using silicon-containing compounds such as Si alkoxides, oligomers thereof, and silicone resins as binder components are known as hard coats,
It is formed on various substrates as a highly weather-resistant coating, an antifouling coating, a hydrophilic coating, etc. for the purpose of protecting the substrate and imparting functionality.

For example, Japanese Patent Application Laid-Open No. 8-164334 discloses a coating film forming composition for coating and adhering a titanium dioxide fine powder having a photocatalytic function to the surface of a substrate, wherein a Si alkoxide or an oligomer thereof is used as a binder component. A composition containing a hydrolyzate is disclosed. Also,
Photocatalyst particles were adhered onto a substrate using a binder containing a silicon compound such as polyorganosiloxane (JP-A-8-67835) as a binder of an inorganic paint containing a component having antibacterial performance, and a silicone resin or the like as a binder. Photocatalysts (JP-A-7-171408) are also known.

In order to impart sufficient water resistance or alkali resistance to an inorganic film to be formed, an inorganic coating agent containing such a silicon-containing compound as a binder component has to be used.
Usually, it is necessary to perform heat treatment at a high temperature of about 300 to 700 ° C. However, when heat treatment is performed at such a high temperature, it is necessary to use a substrate having excellent heat resistance, and there is a problem that the types of substrates that can be used are limited.

[0005] For this reason, usually, the inorganic coating agent is often used after being cured at a relatively low temperature of about 300.degree. As a result, sufficient durability cannot be imparted to the formed inorganic film. For example, when the film is used for a long time in an environment exposed to wind and rain, or in an environment exposed to warm water or an alkaline detergent, the film may deteriorate. Progresses, elution and peeling of the film occur, and it is impossible to maintain various functions such as abrasion resistance and antifouling property of the film for a long time. Also, W
O97 / 00134 is a method for improving the durability of an inorganic coating film by forming a film such as SiO ₂ —ZrO ₂ or SiO ₂ —Al ₂ O ₃ by mixing a gel such as an oxide or a hydroxide. However, since this method is a modification method by mixing particles, a sufficient modification effect cannot be obtained.

On the other hand, S formed by the sol-gel method
It is known that an iO ₂ —Al ₂ O ₃ composite oxide film and a SiO ₂ —ZrO ₂ composite oxide film have high water resistance and alkali resistance. However, among the raw materials used to form such a composite oxide film, Zr alkoxides and Al alkoxides have a very high hydrolysis rate as compared with Si alkoxides, and the hydrolysis rates in the coating agent are significantly different. Of the alkoxide will be present. For this reason, in such an inorganic coating agent, there is a problem that hydrolysis easily proceeds non-uniformly, aggregation of the hydrolyzate occurs, the coating solution becomes cloudy, and a precipitate is formed. For this reason, in order to form a good composite oxide film, it is necessary to strictly control the amount of water and acidity in the raw material, the humidity in the air, and the like, and to fire at a high temperature of 400 ° C. or higher.

[0007]

SUMMARY OF THE INVENTION The main object of the present invention is to:
An object of the present invention is to provide an inorganic coating agent capable of forming an inorganic film excellent in warm water resistance, alkali resistance and the like only by heating at a relatively low temperature.

[0008]

The inventor of the present invention has conducted intensive studies in view of the state of the prior art as described above and as a result,
A liquid coating obtained by hydrolyzing a silicon-containing alkoxide in a mixed solvent of an organic solvent and then adding at least one complex compound selected from a Zr complex, an Al complex and a Ti complex to carry out hydrolysis polycondensation. According to the agent
After applying this to a base material, it is heated at a relatively low temperature, so that Zr, Al, Ti
It has been found that the oxide such as is incorporated, the inorganic coating film is uniformly improved, and an inorganic film having extremely good warm water resistance and alkali resistance can be formed, and the present invention has been completed.

That is, the present invention provides the following method for producing an inorganic coating agent, an inorganic coating agent, a method for forming an inorganic film, and an article having an inorganic film. 1. After hydrolyzing a silicon-containing alkoxide compound in a water-organic solvent mixed solvent, a Zr complex, an Al complex and T
A method for producing an inorganic coating agent, comprising adding at least one complex compound selected from i-complexes and subjecting them to hydrolysis polycondensation. 2. The silicon-containing alkoxide compound has the formula: Si (O
R) ₄ (wherein R is the same or different and is an alkyl group having 1 to 4 carbon atoms), and at least one selected from oligomers thereof and a tetraalkoxysilane represented by the formula: Item 1 is at least one selected from the group consisting of a Zr-β diketone complex, a Zr-β ketone ester complex, an Al-β diketone complex, an Al-β ketone ester complex, a Ti-β diketone complex, and a Ti-β ketone ester complex. The described method. 3. Item 7. An inorganic coating agent obtained by the method according to Item 1 or 2. 4. Item 4. The inorganic coating agent according to item 3, which contains metal oxide particles. 5. Item 5. The inorganic coating agent according to Item 4, wherein the metal oxide particles are blended as a sol containing the metal oxide particles. 6. Item 6. A method for forming an inorganic film, comprising applying the inorganic coating agent according to any one of Items 3 to 5 to a base material and then curing the applied material. 7. An article having an inorganic film formed by the method of claim 6.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the silicon-containing alkoxide compound has the formula: Si (OR) ₄ (where R is the same or different and is an alkyl group having 1 to 4 carbon atoms). The represented tetraalkoxysilane, its oligomer, and the like can be suitably used.

In the above general formula, the alkyl group having 1 to 4 carbon atoms represented by R is a straight-chain methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl or sec-butyl group. Alternatively, a branched alkyl group can be exemplified. In the above tetraalkoxide, all the alkyl groups may be the same, or some or all may be different.

Specific examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane and the like.

As the oligomer of tetraalkoxysilane, for example, dimer to 10-mer can be used.

The silicon-containing alkoxide compounds can be used alone or as a mixture of two or more.

In the present invention, first, the silicon-containing alkoxide compound is hydrolyzed in a mixed solvent of water and an organic solvent.

As the organic solvent to be mixed in the water-organic solvent mixed solvent, for example, alcohols, esters, cellosolves and the like can be used. Among them, alcohols having an alkyl group having 1 to 4 carbon atoms such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, sec-butanol, tert-butanol and the like. alcohol,
Examples of tetrahydrofurfuryl alcohol and the like, examples of esters include ethyl acetate and butyl acetate, and examples of cellosolves include methyl cellosolve and ethyl cellosolve. The mixing ratio of water and the organic solvent is preferably about 5 to 80% by weight, with the total amount of water and the organic solvent being 100% by weight. If the water content is too small, the hydrolysis of the silicon-containing alkoxide compound does not proceed sufficiently, and the durability of the formed inorganic film tends to be insufficient. On the other hand, if the water content is too large, the film-forming property is reduced. Not preferred.

The concentration of the silicon-containing alkoxide compound to be mixed in the mixed solvent of water and organic solvent may be about 1 to 60% by weight, preferably about 5 to 40% by weight.

In order for the hydrolysis reaction to proceed sufficiently, the pH of the mixed solvent of water and organic solvent is preferably about 5 or less, more preferably about 1 to 4.
When the pH of the water-organic solvent mixed solvent exceeds 5, for example, an inorganic acid such as nitric acid, hydrochloric acid, or acetic acid, acetic acid, or an organic acid such as p-toluenesulfonic acid is added to lower the pH to 5 or less. Adjust it.

The hydrolysis reaction of the silicon-containing alkoxide compound is carried out by stirring or leaving at a temperature of about room temperature to about 95 ° C. for about 1 hour to about 1 week, preferably at about room temperature to about 50 ° C. for about 6 hours to 72 hours. be able to.
In such hydrolysis conditions, when a low temperature reaction condition is employed, the hydrolysis reaction is performed for as long as possible within the above range, and when a high temperature reaction condition is employed, the hydrolysis reaction is performed within the above range. It is preferable to carry out the hydrolysis reaction for a short time.

Next, Zr is added to the mixed solvent after hydrolysis.
At least one complex compound selected from a complex, an Al complex, and a Ti complex is added and hydrolytic polycondensation is performed.

As the Zr complex, for example, a Zr-β diketone complex, a Zr-β ketone ester complex and the like can be used. As the Al complex, an Al-β diketone complex, A
l-β ketone ester complex or the like can be used;
As the complex, a Ti-β diketone complex, a Ti-β ketone ester complex, or the like can be used.

Among these, examples of the Zr complex include a general formula: Zr (OR) _m (S) _n (where R is a carbon number of 1 to 4)
S represents β-diketone or β-ketone ester, m represents an integer of 0 to 3, and n represents an integer of (4-m). The compound represented by the general formula: Al (O 2)
R) _m (S) _n (wherein, R represents an alkyl group having 1 to 4 carbon atoms, S represents β-diketone or β-ketone ester, m represents an integer of 0 to 2, and n represents Represents an integer of (3-m).)
Examples of the complex include a general formula: Ti (OR) _m (S) _n (where R represents an alkyl group having 1 to 4 carbon atoms, and S represents β-
Represents a diketone or β-ketone ester, and m is 0 to 3
And n represents an integer of (4-m). )).

Among these, specific examples of the Zr-β diketone complex include Zr-acetylacetonate and Zr-benzoylacetonate. Specific examples of the Zr-β ketone ester complex include Zr-acetoacetic acid. Examples of the Al-β diketone complex include Al-acetylacetonate and Al-benzoylacetonate. Specific examples of the Al-β ketone ester complex include Al-acetoacetic acid. A methyl complex and the like can be exemplified, and a specific example of the Ti-β diketone complex is Ti-
Acetylacetonate, Ti-benzoylacetonate and the like can be exemplified, and specific examples of the Ti-β ketone ester complex include a Ti-acetoacetate methyl complex and the like.

These Zr complexes, Al complexes and Ti complexes can be used alone or in combination of two or more.

The method of adding at least one complex compound selected from the group consisting of a Zr complex, an Al complex and a Ti complex is not particularly limited, and a liquid compound may be added in a mixed solvent containing a hydrolyzate of a silicon-containing alkoxide compound. May be directly mixed with the organic solvent such as alcohols, ethers such as tetrahydrofuran, esters such as ethyl acetate, ketones such as 2-butanone at room temperature or under heating. It is preferable to add after dissolving.

The amount of at least one complex compound selected from the group consisting of Zr complex, Al complex and Ti complex depends on the amount of SiO ₂ formed from the hydrolyzate of the silicon-containing alkoxide compound in the finally formed inorganic film. Assuming that the total amount of ZrO ₂ formed from the hydrolyzate of the Zr complex, Al ₂ O ₃ formed from the hydrolyzate of the Al complex, and TiO ₂ formed from the hydrolyzate of the Ti complex is 100% by weight, ZrO 2 ₂ , the total amount of Al ₂ O ₃ and TiO ₂ is 0.
The amount is preferably about 2 to 4% by weight. still,
When one or two of the Zr complex, the Al complex and the Ti complex are added, the amount of oxide based on them is 0.2 to 0.2.
The amount may be in the range of about 4% by weight. When the ZrO ₂ amount, Al ₂ O ₃ amount and TiO ₂ amount in the formed inorganic film are too small, the effect of modifying alkali resistance and hot water resistance is not sufficient, but when these compounding amounts are too large. Also, alkali resistance and warm water resistance tend to deteriorate.

The pH of the solution at the time of performing the hydrolysis polycondensation reaction is preferably about 5 or less, more preferably about 1 to 4. If the pH is too high, the pH may be adjusted to 5 or less by adding an inorganic acid such as nitric acid, hydrochloric acid, or acetic acid, acetic acid, or an organic acid such as p-toluenesulfonic acid, as in the above case. .

The hydrolysis polycondensation reaction can be carried out by stirring or standing at room temperature to about 95 ° C. for about 30 minutes to about 1 week, preferably at room temperature to about 80 ° C. for about 1 hour to 72 hours. In such hydrolysis polycondensation reaction conditions, when a low temperature reaction condition is employed, the hydrolysis polycondensation reaction is performed for as long as possible within the above range, and when a high temperature reaction condition is employed, It is preferable to carry out the hydrolysis-polycondensation reaction within the above range for as short a time as possible.

After hydrolyzing the silicon-containing alkoxide compound in a water-organic solvent mixed solvent as described above, at least one compound selected from a Zr complex, an Al complex and a Ti complex is added, and the resulting mixture is subjected to hydrolysis polycondensation. By doing so, a uniform polycondensate is formed in the mixed solvent. By using a coating agent containing this polycondensate, an inorganic coating film having excellent (hot) water resistance, alkali resistance and the like can be formed only by heating at a relatively low temperature. On the other hand, if a Zr complex, an Al complex, a Ti complex, or the like is added before the silicon-containing alkoxide compound is hydrolyzed, hydrolysis of the silicon-containing alkoxide compound is inhibited, and a film having excellent durability cannot be formed.

The inorganic coating agent obtained by the above method may further contain various metal oxide particles, if necessary.

As the metal oxide particles, various components conventionally mixed in the inorganic film may be appropriately selected and used according to the purpose of use.

Particularly, in the inorganic coating agent obtained by the method of the present invention, metal oxide particles having an average particle diameter of about 1 nm to 30 nm are preferable from the viewpoint of transparency and durability of the formed inorganic film. Usually, such metal oxide particles are
It is blended in a coating agent as a sol containing a metal oxide. Examples of such a sol include silica sol, alumina sol, silica-alumina composite sol, zirconia sol, titania sol and the like. In particular, in order to form an inorganic film having good transparency, it is preferable to use an acid peptizing sol peptized with hydrochloric acid or nitric acid or a sol previously dispersed in an organic solvent among these sols.

With respect to the metal oxide particles, if the metal oxide particles are mixed in a large amount, the durability of the formed inorganic film is reduced. Therefore, usually, the weight of the formed inorganic film is 100% by weight and the amount of the metal oxide is 50% by weight. The content is preferably the following or less, more preferably 45% by weight or less.

The metal oxide particles or the sol thereof can be added to the coating agent at any time. For example,
The silicon-containing alkoxy compound may be added to the mixed solvent before hydrolysis, or may be added to the finally obtained coating agent. When the acid peptizer sol of the metal oxide is added to the silicon-containing alkoxide compound before hydrolysis of the silicon-containing alkoxide compound, the pH of the mixed solvent containing the silicon-containing alkoxide compound is adjusted to 5 or less due to the acid contained in the acid peptizer sol. In this case, the silicon-containing alkoxide compound can be hydrolyzed without adjusting the pH.

The inorganic coating agent obtained by the method of the present invention may further contain, if necessary, other various additives. For example, when titanium oxide sol is added to a coating agent to provide a photocatalytic function, Au, Pt, P
Metal salts such as d, Cu, Ni, Fe, and Ag can be added. In order to impart antibacterial properties, Cu, Ag
Can add antibacterial metal salts and colloids, etc.
An inorganic antibacterial agent in which Cu or Ag is immobilized on an inorganic carrier by a method such as ion exchange can also be added. Furthermore, in order to impart antifungal properties, an organic antifungal agent that does not decompose or deactivate depending on the pH of the coating agent and does not decompose or deactivate even when the film is cured can be added. It is preferable that these additives are usually contained in an amount of about 0.005 to 2.0% by weight, based on the total weight of the formed inorganic film as 100% by weight.

Further, the coating agent may be a silicon compound having an alkyl group such as methyltriethoxysilane or diethoxydimethylsilane, a silane coupling agent, or the like, in order to enhance film-forming properties and adhesion to a substrate. It can also be added. When these components are blended in a large amount, the durability of the film tends to decrease. Therefore, it is preferable that the content of the inorganic film to be formed be 100% by weight or less and 10% by weight or less.

The coating agent obtained by the method of the present invention comprises:
An inorganic film can be obtained by applying the composition to a substrate and curing the composition. The appropriate amount of the solid content (residue after heating) in the coating agent at the time of application is about 1 to 40% by weight.

The formed inorganic film is composed of SiO ₂ derived from the silicon-containing alkoxide compound used as a raw material,
ZrO ₂ , Al ₂ O ₃ and T derived from at least one complex compound selected from a Zr complex, an Al complex and a Ti complex
It is composed of a composite oxide with at least one oxide selected from iO _{2. When a} metal oxide powder is blended in a coating agent, the composite oxide serves as a binder, and Are dispersed and fixed.

There is no particular limitation on the method of coating the substrate, and the spin coating method, the dip coating method, the flow coating method,
A known method such as a roll coating method and a spray coating method may be appropriately selected. The coating thickness is not particularly limited and may be appropriately determined depending on the purpose of use and the like,
Usually, about 0.1 μm to 10 μm is appropriate.

There is no particular limitation on the type of the base material. For example, base materials of various materials such as glass, plastic, and metal can be used.

The method of curing the applied coating agent is not particularly limited.
At a temperature of at least about 100 ° C.
By heating for about 1 minute to 1 hour, it can be easily cured. If the heating temperature is too low, the dehydration condensation of the binder component does not sufficiently proceed, and good durability may not be obtained. The upper limit of the heating temperature is not particularly limited, and the heating temperature may be appropriately determined according to the type of the base material. For example, the heating may be performed at a high temperature of about 700 ° C., but the heating temperature is usually up to about 400 ° C. Is enough. In addition to the heating method, when the heat-resistant temperature of the substrate is low, it can be cured by irradiation with light, ultraviolet rays, electron beams, microwaves, or the like.

A primer may be previously applied to a plastic substrate or a substrate having an organic coating film in order to enhance the adhesion of the inorganic film. As the primer, a known primer such as a urethane resin, an epoxy resin, an acrylic resin, an acrylic urethane resin, an acrylic silicone resin, and a silicone resin can be used. It is desirable that the primer be cured before application of the inorganic coating agent by a method such as room temperature curing, heat curing, curing by irradiation with light, ultraviolet rays, electron beam microwaves or the like.

[0043]

According to the inorganic coating agent obtained by the method of the present invention, an inorganic film excellent in (hot) water resistance, alkali resistance and the like can be formed only by heating at a relatively low temperature. For this reason, by adding various metal oxides and other additives to the inorganic coating agent, if necessary, it can be used for outdoor members exposed to the elements, such as outdoor members exposed to wind and rain, and water surrounding members using alkaline detergents and the like. Various functions such as wear resistance and antifouling property can be provided for a long term.

[0044]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. Silica sol (trade name Example 1 Purified water 45.0 g: SNOWTEX O, Nissan Chemical Co., Ltd. SiO ₂ 20 wt% content, pH
= 2-4) 15.0 g and 36.5 g of methanol were added and stirred. This tetramethoxysilane oligomer (trade name: MS-51, manufactured by Mitsubishi Chemical Co., SiO ₂ in terms of 5
(Containing 1% by weight) and stirred at room temperature for 48 hours to hydrolyze the tetramethoxysilane oligomer. At this time, the pH of the mixed solvent was about 3. 36.4 g of ethanol and 36.2-propanol were added to the obtained liquid.
4 g was added to obtain solution A.

5.0 g of aluminum acetylacetonate (manufactured by Dojindo Laboratories) was added to ethyl acetate 9
It was added to 5.0 g, stirred at room temperature and dissolved to prepare a 5% solution (solution B). Separately, zirconium acetylacetonate (manufactured by Dojindo Laboratories Inc.) 5.0
g was added to 95.0 g of ethyl acetate, and dissolved by stirring while heating at 60 ° C. to prepare a 5% solution (solution C).

9.5 g of solution B and 7.9 g of solution C were added to solution A, and the mixture was stirred at room temperature for 24 hours to prepare an inorganic coating agent (solution D). The heating residue of the solution D at 500 ° C. was 5.0% by weight.

A clean soda lime glass plate subjected to ultrasonic cleaning was immersed in the solution D, dip coated at a pulling rate of 25 mm / min, and dried at 150 ° C. for 30 minutes to form an inorganic film on the glass plate. .

70% by weight of the formed inorganic film
Is derived from tetramethoxysilane oligomer, aluminum acetylacetonate and zirconium acetylacetonate and has a composition ratio of SiO ₂ : AlO _3/2 : ZrO
₂ = 97.5: 1.1: 1.4 complex oxide, and the remainder was SiO ₂ particles contained in the silica sol dispersed and fixed in the complex oxide. Example 2 In 47.7 g of purified water, a nitric acid peptizing sol of titanium oxide as a photocatalyst (trade name: STS-01, manufactured by Ishihara Techno Co., Ltd.)
13.3 g of TiO _{2 (} containing 30% by weight, pH = 1.3) and 36.7 g of methanol were added and stirred, and then tetramethoxysilane oligomer (trade name: MS-51, manufactured by Mitsubishi Chemical Corporation, SiO ₂ ) 11.4).
g was added and stirred at room temperature for 48 hours to hydrolyze the tetramethoxysilane oligomer. The mixed solvent p
H was about 2.5. Add ethanol 3 to the obtained liquid.
6.7 g and 36.7 g of 2-propanol were added, and E was added.
Liquid.

9.5 g of Solution B and 7.9 g of Solution C used in Example 1 were added to Solution E, and the mixture was stirred at room temperature for 24 hours to prepare an inorganic coating agent containing a photocatalyst (Solution F). .
The heating residue of the solution F at 500 ° C. was 5.0% by weight.

The soda lime glass plate cleaned by ultrasonic cleaning is immersed in the solution F, dip coated at a pulling rate of 25 mm / min, dried at 150 ° C. for 30 minutes, and coated with an inorganic coating containing a photocatalyst on the glass plate. A film was formed.

In the formed inorganic film, 60% by weight
Is derived from tetramethoxysilane oligomer, aluminum acetylacetonate and zirconium acetylacetonate and has a composition ratio of SiO ₂ : AlO _3/2 : ZrO
₂ = 97.1: 1.3: 1.7 is a composite oxide, and the balance is TiO ₂ contained in titanium oxide nitrate peptizer.
The particles were dispersed and fixed in the composite oxide. Comparative Example 1 45.0 g of purified water was mixed with silica sol (trade name: Snowtex O, manufactured by Nissan Chemical Industries, Ltd., containing 20% by weight of SiO ₂ )
(pH = 2-4) 15.0 g and methanol 42.1 g were added and stirred. 13.7 g of a tetramethoxysilane oligomer (trade name: MS-51, manufactured by Mitsubishi Chemical Corporation, containing 51% by weight in terms of SiO ₂ ) was added thereto, and the mixture was added at room temperature for 48 hours.
After stirring for an hour, the tetramethoxysilane oligomer was hydrolyzed. At this time, the pH of the mixed solvent was about 3. 42.1 g of ethanol and 2-propanol 4 were added to the obtained solution.
2.1 g was added, and the mixture was stirred at room temperature for 24 hours to obtain a solution G. The heating residue of the solution G at 500 ° C. was 5.0% by weight.

A clean soda-lime glass plate subjected to ultrasonic cleaning was immersed in the solution G, dip-coated at a pulling rate of 25 mm / min, and dried at 150 ° C. for 30 minutes to form an inorganic film on the glass plate. .

70% by weight of the formed inorganic film
Is amorphous silica derived from a tetramethoxysilane oligomer, and the remainder is SiO ₂ particles contained in the silica sol dispersed and fixed in the amorphous silica. Comparative Example 2 Silica sol (trade name: Snowtex O, manufactured by Nissan Chemical Co., Ltd., containing 20% by weight of SiO ₂ ) in 45.0 g of purified water,
(pH = 2-4) 15.0 g and methanol 39.7 g were added and stirred. 13.6 g of a tetramethoxysilane oligomer (trade name: MS-51, manufactured by Mitsubishi Chemical Corporation, containing 51% by weight in terms of SiO ₂ ) was added thereto, and the mixture was stirred at room temperature for 48 hours to hydrolyze the tetramethoxysilane oligomer. Decomposed. At this time, the pH of the mixed solvent was about 3. 39.7 g of ethanol and 2-propanol 3 were added to the obtained solution.
9.7 g was added to obtain solution H.

0.5 g of aluminum sec-butoxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added to 9.5 of 2-propanol.
g, and stirred and dissolved at room temperature to give a 5% solution (Solution I).
Was prepared.

7.3 g of solution I was added to solution H, and the mixture was stirred at room temperature for 24 hours to prepare an inorganic coating agent (solution J). At this time, as the solution I was added to the solution H, clouding of the solution was confirmed, which is considered to be due to the rapid hydrolysis of aluminum sec-butoxide. The heating residue of the solution J at 500 ° C was 5.0% by weight.

A clean soda lime glass plate subjected to ultrasonic cleaning was immersed in the J solution, dip coated at a pulling rate of 25 mm / min, and dried at 150 ° C. for 30 minutes to form an inorganic film on the glass plate.

70% by weight of the formed inorganic film
Is a tetramethoxysilane oligomer and aluminum s
ec-butoxide derived from SiO ₂ : Al
The composite oxide was O _3/2 = 98.9: 1.1, and the remainder was SiO ₂ particles contained in the silica sol dispersed and fixed in the composite oxide. Comparative Example 3 45.0 g of purified water was mixed with silica sol (trade name: Snowtex O, manufactured by Nissan Chemical Co., Ltd., containing 20% by weight of SiO ₂ )
(pH = 2-4) 15.0 g and methanol 40.1 g were added and stirred. A tetramethoxysilane oligomer (trade name: MS-51, manufactured by Mitsubishi Chemical Corporation, SiO ₂ )
13.5 g) was added at room temperature.
After stirring for 8 hours, the tetramethoxysilane oligomer was hydrolyzed. At this time, the pH of the mixed solvent was about 3.
40.1 g of ethanol and 40.1 g of 2-propanol were added to the obtained liquid to obtain a K liquid.

85% of zirconium n-butoxide n-
0.5 g of butanol solution (manufactured by Wako Pure Chemical Industries, Ltd.)
-Butanol was added to 8.0 g, and dissolved by stirring at room temperature to prepare a 5% solution (L solution).

When 6.2 g of the L solution was added to the K solution, a white precipitate was formed, which is considered to be due to the rapid hydrolysis of zirconium n-butoxide, to prepare a uniform inorganic coating agent. Could not be done. Comparative Example 4 A nitric acid peptizing sol of titanium oxide as a photocatalyst (trade name: STS-01, manufactured by Ishihara Techno Co., Ltd.) was added to 47.7 g of purified water.
13.3 g of TiO _{2 (} containing 30% by weight, pH = 1.3) and 42.4 g of methanol were added and stirred, and then tetramethoxysilane oligomer (trade name: MS-51, manufactured by Mitsubishi Chemical Corporation, SiO ₂ ) 11.8).
g was added and stirred at room temperature for 48 hours to hydrolyze the tetramethoxysilane oligomer. The mixed solvent p
H was about 2.5. Ethanol 42.
4 g of 4-propanol and 42.4 g of 2-propanol were added, and the mixture was stirred at room temperature for 24 hours to prepare an inorganic coating agent containing a photocatalyst (M solution). The heating residue of the liquid M at 500 ° C. was 5.0% by weight.

A clean soda lime glass plate subjected to ultrasonic cleaning was immersed in the M solution, dip coated at a pulling rate of 25 mm / min, dried at 150 ° C. for 30 minutes, and an inorganic film containing a photocatalyst was placed on the glass plate. Formed.

60% by weight of the formed inorganic film
Is amorphous silica derived from a tetramethoxysilane oligomer, and the remainder was TiO ₂ particles contained in a nitric acid peptizing sol of titanium oxide dispersed and fixed in amorphous silica. Evaluation of hot water resistance The glass plates on which the inorganic films obtained in Examples 1 and 2 and Comparative Examples 1, 2 and 4 were formed were allowed to stand at room temperature for 10 days, and then placed in a beaker containing 900 ml of boiling ion-exchanged water. Get in,
Heated for 1 hour to continue boiling, then pulled up and dried for 1 hour at room temperature. The pencil hardness of the dried inorganic film was measured, and the deterioration of the film was evaluated. Evaluation of alkali resistance The glass plates on which the inorganic films obtained in Examples 1 and 2 and Comparative Examples 1, 2 and 4 were formed were allowed to stand at room temperature for 10 days, and then 5%
Immerse in an aqueous sodium hydroxide solution, pull up every hour, wash with ion-exchanged water, dry at room temperature for one hour, visually observe the surface condition of the inorganic film, and immerse it until deterioration of the film is observed. The time was measured.

The compositions and test results of the inorganic films in the above Examples and Comparative Examples are shown in Tables 1 to 3 below.

[0063]

[Table 1]

[0064]

[Table 2]

[0065]

[Table 3]

Claims (7)

[Claims] 1. A method comprising the steps of hydrolyzing a silicon-containing alkoxide compound in a water-organic solvent mixed solvent, adding at least one complex compound selected from a Zr complex, an Al complex and a Ti complex, and performing hydrolysis polycondensation. A method for producing an inorganic coating agent, comprising: 2. The method of claim 1, wherein the silicon-containing alkoxide compound has the formula:
i (OR) _{4 wherein} R is the same or different and has 1 carbon atom
４4 alkyl groups. )) And at least one selected from oligomers thereof, wherein the complex compound is a Zr-β diketone complex, Zr-
β ketone ester complex, Al-β diketone complex, Al-
β ketone ester complex, Ti-β diketone complex and Ti
The method according to claim 1, wherein the method is at least one selected from -β ketone ester complexes. 3. An inorganic coating agent obtained by the method according to claim 1. 4. The inorganic coating agent according to claim 3, comprising metal oxide particles. 5. The inorganic coating agent according to claim 4, wherein the metal oxide particles are blended as a sol containing the metal oxide particles. 6. A method for forming an inorganic film, comprising applying the inorganic coating agent according to any one of claims 3 to 5 to a substrate and curing the applied material. 7. An article having an inorganic film formed by the method of claim 6.