JPH0971438A - Composition for film formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition for film formation, capable ofeasily preparing a coating solution because of its good solubility to organic solvent, excellent in preservability in the presence of moisture, and good in coating workability, comprising a zirconium alkoxide chelate compound prepared by chelating (A) a zirconium alkoxide with (B) a β-ketoester compound and (C) β-diketone compound. SOLUTION: This composition comprises a zirconium alkoxide chelate compound which is prepared by chelating the component A with the components B and C at the weight ratio A/B/C of (x:y:z) ((x), (y) and (z) satisfy the following relationships: 1<=(y/x)<=3, and 1<=(z/x)<=3). The component A is e.g. a zirconium tetraalkoxide; the component B is e.g. methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, butyl acetoacetate; and the component C is e.g. acetylacetone. In this composition, (D) and organosilicon compound may be contained in the component A; in this case, the ratio for the components A and D is 0.2-2 in terms of the molar ratio Si/Zr.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a film forming composition, and more particularly to a composition having excellent coating properties and storage stability for forming a film on a substrate such as glass, metal or semiconductor.

[0002]

2. Description of the Related Art There has been proposed a method of forming a functional thin film, for example, an optical thin film such as an ultraviolet ray shielding thin film, a heat ray reflecting thin film and an antireflection film on a substrate such as glass, metal or semiconductor by a wet method. In order to impart a chemical and mechanical protective function to such a functional thin film, those containing ZiO ₂ are often used in the composition of these coatings. As a starting material for zirconium oxide, a coating liquid composition containing zirconium alkoxide as a main component is used. Since zirconium alkoxide has high reactivity, it rapidly gels and its viscosity rises rapidly, so that coating workability becomes difficult unless it is used within a short period after preparation. Further, when the coating operation is performed in an atmosphere of high humidity, the film surface is whitened, which makes it unusable for applications requiring a transparent appearance. Furthermore, since the water content contained in the coating solution causes a precipitate during storage, there is a problem that the storage stability of the coating solution is poor.

In order to solve such a problem, β-
It has been disclosed to use a coating liquid composition starting from a zirconium alkoxide chelated with a diketone compound or a β-ketoester compound [Togeto et al. Jpn. J. Appl. Phys. Vol. 33 (1994) pp. L1181-L11
84, and Journal of Sol-Gel Science and Technolog
y, 2, 581-585 (1994)]. However, in order to improve stability, a chelate compound in which 2 molecules of acetylacetone are coordinated with 1 molecule of zirconium alkoxide as a β-diketone compound has low solubility in an organic solvent, and it is difficult to arbitrarily adjust the concentration of the coating solution. The range is significantly limited. Further, even when the β-ketoester compound was used as a chelating agent, the stability against water was not sufficient.

As described above, hitherto, no coating liquid composition containing a zirconium oxide raw material sufficiently satisfying both the stability in water and the solubility in an organic solvent has been known.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, has good solubility in organic solvents, can easily prepare a coating solution, has excellent storage stability against moisture, and can be used for coating. It is an object of the present invention to provide a film-forming composition having good workability.

[0006]

In order to solve the above problems, in the present invention, β having good solubility in an organic solvent is used.
A film-forming composition containing a ketoester compound and a β-diketone compound having excellent stability, which simultaneously chelate a zirconium alkoxide chelate is used.

As zirconium alkoxides used in the present invention, tetramethoxyzirconium, tetraethoxyzirconium, tetraisopropoxyzirconium, tetraisopropoxyzirconium isopropanol complex, tetra n-propoxyzirconium, tetraisobutoxy zirconium, tetra n-butoxy zirconium, Tetra sec-butoxy zirconium, tetra t-
Zirconium tetraalkoxides such as butoxyzirconium can be conveniently used. It is also possible to use zirconium halide alkoxides such as zirconium monochloride trialkoxide and zirconium dichloride dialkoxide. It is also possible to use alkoxyzirconium organic acid salts in which at least one of the alkoxy groups of the zirconium alkoxide is replaced with an organic acid such as acetic acid, propionic acid, butanoic acid, acrylic acid or methacrylic acid.

A chelating reagent for chelating the zirconium alkoxide will be described. As the β-ketoester compound, acetoacetic acid esters such as methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, butyl acetoacetate and phenyl acetoacetate can be enumerated. Methyl acetate and ethyl acetoacetate are preferable because they can be obtained relatively inexpensively. Examples of the β-diketone compound include acetylacetone, 2,2,6,6-tetramethyl-3,5-heptanedione, vinylacetylacetone, and the like, and acetylacetone is preferable because it is inexpensively available.

Next, the mixing ratio of the chelating agent to the zirconium alkoxide will be described. The molar ratio of zirconium alkoxide, β-ketoester compound and β-diketone compound is (zirconium alkoxide):
(Β-ketoester compound): (β-diketone compound)
= x: y: z, 1 ≦ y / x ≦ 3, 1 ≦ z / x ≦ 3
Is preferably within the range. Furthermore, x = y = z = 1
Is more preferable.

In addition to the above-mentioned zirconium alkoxide chelate, the film-forming composition of the present invention may contain a composition as a raw material for oxides of silicon, titanium, cerium, zinc and the like. An organosilicon compound, which is a raw material compound of silicon dioxide, may be contained in order to adjust the film characteristics and the refractive index. The organosilicon compound used is Si (OR) 4 (where R is a methyl group,
A tetraalkoxysilane represented by an ethyl group, a propyl group, or a butyl group) and a hydrolyzed condensate thereof are preferably used. Or SiR'4-n (OR) n,
(Here, R is a methyl group, an ethyl group, a propyl group, or a butyl group, and R'is a methyl group, an ethyl group, a propyl group, a vinyl group, a γ-chloropropyl group, a γ-aminopropyl group, a γ-methacryloxypropyl group. Group, or a γ-mercaptopropyl group, n is an integer of 1 to 3), and so-called silane coupling agents can also be used.

The composition of the present invention may contain an organic silicon compound as described above, and silicon and zirconium can be mixed in any ratio. When tetraalkoxysilane is used as a raw material for silicon dioxide, in order to improve wettability with respect to glass, metal, and semiconductor substrate surface,
Hydrolyzed alkoxysilane is preferably used. An acid catalyst and water are used for the hydrolysis of the alkoxysilane. If the molar ratio Si / Zr is large,
The ratio of the acid catalyst and water to the zirconium chelate compound becomes relatively large, and gelation is likely to occur due to the hydrolysis condensation reaction. However, since the zirconium chelate compound used in the present invention has extremely high stability to water, the alkoxysilane There is no problem even if the amount of hydrolyzate is increased. Usually, a mixture of an organosilicon compound and a zirconium alkoxide chelate represented by a molar ratio Si / Zr of 0.2 to 5.0 is used.

Further, the zirconium chelate compound used in the present invention has remarkably high solubility in an organic solvent, so that it is possible to increase the zirconium chelate compound concentration in order to increase the zirconia content. The coating liquid composition does not whiten even when coated in an atmosphere of high humidity, for example, 70% relative humidity, and the transparency of the film is not impaired. When coating,
It is used by adjusting the viscosity of the liquid by diluting it with an organic solvent so that the value of the total solid content conversion concentration falls within the range of 3 to 15%.

The organic solvent used in the composition of the present invention is
It depends on the coating method. For example, as the organic solvent for the gravure coating method, the flexographic printing method, and the roll coating method, a solvent having a slow evaporation rate is suitable. This is because with a solvent having a high evaporation rate, the solvent evaporates before sufficient leveling is performed. The evaporation rate of the solvent is
It is generally evaluated by the relative evaporation rate index of butyl acetate as 100. A solvent having a value of 40 or less is classified as a solvent having an "extremely slow" evaporation rate, and such a solvent is preferable as an organic solvent for the gravure coating method, the flexographic printing method, and the roll coating method. Examples thereof include ethyl cellosolve, butyl cellosolve, cellosolve acetate, diethylene glycol monoethyl ether, hexylene glycol, diethylene glycol, tripropylene glycol, diacetone alcohol, and tetrahydrofurfuryl alcohol. The coating liquid composition of the present invention preferably contains at least one such solvent, but a plurality of the above solvents may be used in order to adjust the viscosity, surface tension and the like of the coating liquid. A solvent with a high evaporation rate and a relative evaporation rate index of more than 100, such as methanol (61
0), ethanol (340), n-propanol (11
0), isopropanol (300), butanol and the like (the numbers in parentheses represent the above relative evaporation rate index values) when mixed with a solvent having the above relative evaporation rate index of 40 or less, It is preferable that 50% by volume of the solvent having a relative evaporation rate index of 40 or less is contained in the entire solvent.

The film forming composition of the present invention is prepared as follows. Predetermined amount of zirconium alkoxide, β
-The ketoester compound and the β-diketone compound are added to the organic solvent so as to have a concentration of 20 to 80% by weight and stirred at room temperature for 1 to 5 hours. As a result, a film-forming composition containing a zirconium alkoxide chelate is obtained.

In the case where the composition for forming a film contains a chelate of zirconium alkoxide, a composition as a raw material for oxides of silicon, titanium, cerium, zinc, etc., for example, when an organic silicon compound is contained. ,
The alkoxysilane and the acid catalyst were sequentially added to an organic solvent and stirred at room temperature for 1 to 5 hours to obtain a solution in which the alkoxysilane was partially hydrolyzed, and then the organic solvent, zirconium alkoxide, β-ketoester compound and By adding the β-diketone compound and stirring at room temperature for 1 to 5 hours, a film-forming composition containing a zirconium alkoxide chelate and an alkoxysilane hydrolyzate can be obtained.

The coating method is not particularly limited, but examples thereof include a spin coating method, a dip coating method, a spray coating method and a printing method.
In particular, printing methods such as a gravure coating method, a flexographic printing method, a roll coating method, and a screen printing method are preferable because they have high productivity and high use efficiency of the coating liquid composition.

The composition for forming a film of the present invention is applied onto a substrate by the above-mentioned coating method, then dried in an oxidizing atmosphere at a temperature of 100 to 300 ° C. for 5 to 200 minutes, and then 500 to 700 ° C. or higher. By firing at a temperature of 10 seconds to 5 minutes, a thin film of an oxide containing zirconia having a thickness of 20 to 200 nm is manufactured.

The action of the zirconium compound used in the present invention will be described below. The zirconium compound used in the present invention has excellent stability in water, while exhibiting excellent solubility in organic solvents. The reason for this can be explained as follows, though it is beyond the scope of estimation. The β-diketone compound used as a chelating agent for zirconium alkoxide is present in the solution as an equilibrium mixture of keto form and enol form as shown below, taking acetylacetone as an example. CH ₃ COCH ₂ COCH ₃ (keto form) CH ₃ COCH = C (OH) CH ₃ (enol form)

Under neutral conditions such as in an organic solvent, it is known that 70% of acetylacetone exists in the enol form. This enol form strongly binds with metal ions to form a chelate complex and suppresses the hydrolysis reaction. On the other hand, in the case of the β-ketoester compound, when ethyl acetoacetate is taken as an example, an equilibrium mixture exists as in the case of acetylacetone as follows,
Only about 8% of the enol form is present. CH ₃ COCH ₂ COOCH ₂ CH ₃ (keto form) CH ₃ C (OH) = CHCOOCH ₂ CH ₃ (enol form)

Therefore, acetylacetone forms a more stable metal chelate complex than ethyl acetoacetate. On the other hand, a β-ketoester compound such as ethyl acetoacetate probably has a hydrophobic ethyl group or other alkyl group or phenyl group,
It has high solubility in organic solvents. The β-keto (alkyl) ester compound generally has an alkyl group having a high affinity for an organic solvent, and thus has a high solubility. For these reasons, it is explained that the zirconium compound used in the present invention has excellent stability in water and excellent solubility in organic solvents.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the present invention will be described below, but the present invention is not limited thereto. Example 1 Ethyl cellosolve 75.0 g, tetraethoxysilane multimer (mixture of monomer to hexamer, Colcoat Co., trade name "ethyl silicate 40") 67.0 g, concentration 0.1 mol / l Add 8.0 g of hydrochloric acid in sequence and add 2 at room temperature.
Stir for hours. After completion of the reaction, the mixture was cooled to room temperature, then ethyl cellosolve 437.4 g, ethyl acetoacetate 77.3.
g, 59.3 g of acetylacetone and 276.0 g of tetra-n-butoxyzirconium were added and stirred at room temperature for 2 hours to obtain a coating liquid composition for forming a film. This composition had Si / Zr = 3/4 (molar ratio), a solid content of 10%, and a viscosity of 4 cp (25 ° C.). 4 of this composition
It was stored for 60 days in a constant temperature bath kept at 0 ° C, but there was no change. Furthermore, when 1 g of pure water was added to 10 g of the coating liquid composition at room temperature and the stability against water was evaluated, gelation was not observed even when 8 g was added. $ The composition (10 days after preparation) on a 3.4 mm thick soda lime glass plate by the gravure coating method
Was coated in an atmosphere of 70% relative humidity. The composition showed a good leveling property after coating, and became a smooth and uniform film within 1 minute after coating.
After drying at 260 ° C. for 120 minutes, the glass with a coating film was put in an electric furnace at 720 ° C. for 2 minutes to be baked. The highest temperature of glass in the electric furnace was 610 ° C. The thickness of the silica-zirconia layer after firing was 70 nm, the haze ratio was 0.1%, and glass with a coating film having excellent light reflection performance with excellent transparency without whitening was obtained.

Example 2 A coating liquid composition was prepared in the same manner as in Example 1 except that methyl acetoacetate was used instead of ethyl acetoacetate. The solid content was 10% and the viscosity was 4 cp. This composition was stored for 60 days in a thermostat kept at 40 ° C., but there was no change in appearance. Furthermore, when 1 g of pure water was added to 10 g of the coating liquid composition at room temperature and the stability against water was evaluated, gelation was not observed even when 8 g was added.

The composition (10 days after preparation) was coated on a 3.4 mm thick soda lime glass by an gravure coating method in an atmosphere of 70% relative humidity. The composition showed a good leveling property after coating, and became a smooth and uniform film within 1 minute after coating. After drying at 260 ° C. for 120 minutes, the glass with a coating film was put in an electric furnace at 720 ° C. for 2 minutes to be baked. The highest temperature of glass in the electric furnace was 610 ° C. The thickness of the silica-zirconia layer after firing was 70 nm, the haze ratio was 0.1%, and glass with a coating film having excellent transparency without whitening was obtained.

Example 3 A coating liquid composition was prepared in the same manner as in Example 1 except that tetra n-propoxy zirconium was used instead of tetra n-butoxy zirconium. The solid content was 10% and the viscosity was 4 cp. 4 of this composition
It was stored for 60 days in a constant temperature bath kept at 0 ° C., but there was no change in appearance. Furthermore, when 1 g of pure water was added to 10 g of the coating liquid composition at room temperature and the stability against water was evaluated, gelation was not observed even when 8 g was added.

3.4m by gravure coating method
m composition of soda lime glass
0 day old) was coated in an atmosphere of 70% relative humidity. The composition had a brush-like streak-like undried coating film surface immediately after coating, but showed good leveling property with the passage of time, and became a smooth and uniform film within 1 minute after coating. After drying at 260 ° C. for 120 minutes, the glass with a coating film was put in an electric furnace at 720 ° C. for 2 minutes to be baked. The highest temperature of glass in the electric furnace was 610 ° C. The thickness of the silica-zirconia layer after firing was 70 nm, the haze ratio was 0.1%, and glass with a coating film having excellent transparency without whitening was obtained.

Comparative Example 1 75.0 g of ethyl cellosolve and a polymer of tetraethoxysilane (trade name "Ethyl Silicate 4 manufactured by Colcoat Co., Ltd.
0 ") 67.0 g, 0.1 mol / l concentration of hydrochloric acid 8.
0 g was sequentially added, and the mixture was stirred at room temperature for 2 hours. After the reaction,
After cooling to room temperature, 419.4 g of ethyl cellosolve, 154.6 g of ethyl acetoacetate, and 276.0 g of tetra-n-butoxyzirconium were added, and the mixture was stirred at room temperature for 2 hours to obtain a coating liquid composition for forming a film. This composition had Si / Zr = 3/4 (molar ratio), a solid content of 10%, and a viscosity of 4 cp (25 ° C.). 1 g of pure water was added to 10 g of the coating liquid composition at room temperature, and the stability against water was evaluated. When 1 g was added, a precipitate was formed, and when 3 g was added, a gel was completely formed.

The composition (10 days after preparation) was coated on a 3.4 mm thick soda lime glass by an gravure coating method in an atmosphere of 70% relative humidity. The composition did not form a smooth and uniform coating film even after 5 minutes or more after coating, and streaks remained. 260 ° C
After drying for 120 minutes, the coated glass is heated to 720 ° C.
It was put in the electric furnace for 2 minutes and baked. The highest temperature of glass in the electric furnace was 610 ° C. The thickness of the silica-zirconia layer after firing was 70 nm, whitening occurred in the streak portion, and glass with a coating film having poor transparency was obtained.

Comparative Example 2 A solution of 115 g of zirconium tetrabutoxide dissolved in 200 g of ethyl cellosolve was added with 60 g of acetylacetone.
Was added to chelate zirconium tetrabutoxide with acetylacetone, but a precipitate was formed due to insufficient solubility in ethyl cellosolve.

[0029]

As described above, according to the present invention, a coating composition that is stable in water and has excellent storage stability can be obtained, and an excellent coating that does not cause whitening during coating can be formed.

Claims (8)

[Claims] 1. A film-forming composition containing a zirconium alkoxide chelate obtained by chelating zirconium alkoxide with a β-ketoester compound and a β-diketone compound. 2. When the molar ratio of the zirconium alkoxide, the β-ketoester compound and the β-diketone compound is represented by (zirconium alkoxide) :( β-ketoester compound) :( β-diketone compound) = x: y: z , 1 ≦ y / x ≦ 3, 1 ≦ z / x ≦ 3.
The film-forming composition as described above. 3. The film-forming composition according to claim 1, wherein the β-ketoester compound is methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, or butyl acetoacetate. 4. The film-forming composition according to claim 1, wherein the β-diketone compound is acetylacetone. 5. The film-forming composition according to claim 1, wherein the zirconium alkoxide is zirconium tetraalkoxide. 6. The film-forming composition according to claim 1, which contains an organosilicon compound in addition to the zirconium alkoxide chelate. 7. The organosilicon compound and the zirconium alkoxide are added in a molar ratio S of silicon and zirconium.
The composition for forming a coating film according to claim 6, which is contained in a ratio of 0.2 to 2 expressed by i / Zr. 8. The intermediate layer composition for forming an ultraviolet absorbing film according to claim 6, wherein the organic silicon compound is a silicon alkoxide.