JP2520223B2 - Coating liquid for forming ultraviolet absorbing film and ultraviolet absorbing glass using the coating liquid - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating solution for forming an ultraviolet absorbing film for forming a zinc oxide-based composite oxide film which absorbs ultraviolet rays and transmits visible rays and by baking, and a method for forming the same. The present invention relates to an ultraviolet absorbing glass in which the coating is formed on a glass substrate and an ultraviolet absorbing glass in which an oxide coating is formed on the ultraviolet absorbing glass to improve optical properties, mechanical properties and chemical properties.

[0002]

2. Description of the Related Art As a method of providing an ultraviolet absorbing coating on a glass substrate, (1) a method of adhering an organic polymer film containing an ultraviolet absorber of an organic or inorganic compound to the surface, (2) ultraviolet absorption There is a method of adhering a film of the substance having the ability itself to the glass surface, and (3) a method of adhering a UV absorber of an organic or inorganic compound to the glass surface with an organic or inorganic compound binder.

The methods (1) and (3) using an organic binder are not suitable for long-term use because the surface hardness of the film itself is low and the film itself is deteriorated by ultraviolet rays.

When the ultraviolet absorbing film is formed on the glass surface by the method (2), vacuum deposition of metal or its oxide,
Physical film forming methods such as sputtering and ion plating are used. However, this method requires a vacuum system, and has the drawbacks that the film forming apparatus becomes large and the manufacturing cost becomes high. Therefore, apart from this method, a coating method has been considered in which a solution of a metal compound is coated on a substrate and baked to deposit a metal oxide film. The metal oxide used is zinc oxide, cerium oxide, iron oxide, vanadium oxide, or the like. Zinc oxide has an advantage that it has an excellent ability to absorb ultraviolet rays and has a very high visible light transmittance. As an example of forming a zinc oxide film using this type of coating liquid and coating method, for example, according to Japanese Patent Laid-Open No. 223111/1993, zinc 2-ethylhexanoate and linoleic acid are used.
There is an example in which a coating liquid is prepared by oxidative polymerization in an oxygen-containing atmosphere at 50 to 200 ° C., and the liquid is applied and fired, and it is reported that a transparent film was obtained.

However, although zinc oxide has an ultraviolet absorbing ability superior to that of other metal oxides, it has hardly been put to practical use. This is because the zinc oxide film has a low surface hardness, is easily scratched, and is attacked by acid or alkali. JP-A-5-147978 discloses a method in which a solution of silicon, zirconium or a compound thereof is applied and baked on a zinc oxide film on a glass surface to provide a protective film in order to eliminate this defect. However, it is complicated and time-consuming to separately provide the oxide protective film on the ultraviolet absorbing film.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned problems and to easily and inexpensively produce an ultraviolet absorbing film on a glass substrate, and earnestly conduct research to develop a material suitable for the method. As a result, by adding ethanolamine to the mixed solution of fatty acid zinc, zirconium alkoxide and / or aluminum alkoxide, the solution became homogeneous and stabilized, and this solution was applied to a glass substrate and baked at a temperature of 400 ° C or higher. -The present invention has been accomplished by finding that a zinc oxide-based composite oxide film is formed by oxidation, and that the purpose can be easily achieved.

That is, the present invention provides a dense film of a high-hardness zinc oxide-based composite oxide having an excellent ultraviolet absorption ability, which is impossible with the prior art, and a coating solution for easily and inexpensively forming the film and its coating film. The present invention provides a forming method, an ultraviolet absorbing glass having the film formed on a glass substrate, and an ultraviolet absorbing glass having an oxide film formed on the ultraviolet absorbing glass.

The coating solution of the present invention has a weight which is reduced by thermal decomposition during firing, that is, an organic substance, as compared with a coating solution prepared by a conventional method, that is, a coating solution prepared by oxidative polymerization of zinc 2-ethylhexanoate and linoleic acid. The content is extremely low, which is advantageous from the viewpoint of forming a dense film. Furthermore, since it does not require heating or atmosphere control when preparing the coating liquid, the manufacturing cost is also very low, which is economically advantageous. Is.

In the method for producing the coating liquid of the present invention, first, fatty acid zinc and zirconium alkoxide and / or aluminum alkoxide are organically adjusted so that the Zn concentration becomes 1 to 9 (mol ratio) with respect to the Zr and / or Al concentration. Mix in solvent. At this time, the ratio of zirconium alkoxide and aluminum alkoxide to be mixed is not particularly limited, and either one may be used alone or both substances may be used in an arbitrary blend. However, the Zn ratio and the (Zr + Al) amount are preferably the above-mentioned molar ratios in consideration of the ultraviolet absorbing ability and the hardness of the film. As the zinc content increases, the UV absorption capacity increases, but the hardness of the film decreases. On the other hand, when the zirconium and aluminum components increase in hardness, the hardness increases but the ultraviolet absorption ability decreases. Therefore, the Zn concentration is (Zr + Al)
The concentration is preferably 1 to 9 (mol ratio).

Examples of the fatty acid zinc used as the Zn raw material include zinc acetate, zinc propionate, zinc butyrate, zinc valerate, zinc caproate, etc., but the fatty acid salt having a large number of carbons has a large weight loss during thermal decomposition. Therefore, fatty acid zinc having a small number of carbon atoms is more preferable. Examples of the organic solvent used include alcohol solvents such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol and 2-butanol, ethylene glycol,
Examples thereof include glycols such as propylene glycol and glycol ethers such as methoxyethanol and ethoxyethanol. Of these organic solvents, only one kind may be used, but two or more kinds may be mixed and used. As the amount of the organic solvent, the Zn concentration is 0.1 to 2 mol
/ L is preferred. This amount is an amount for keeping the zinc concentration in the liquid at an appropriate value and for making the viscosity suitable for coating. If the amount of solvent is large, the zinc concentration will be low, and the coating thickness is thin and the ultraviolet absorption effect is not sufficient. A film is formed, which is not preferable.
On the other hand, when the amount of solvent is small, the viscosity becomes high and it becomes unsuitable as a coating liquid, and the coating film is cracked or a film having a low visible light transmittance is formed.

Depending on the zinc concentration and the alkoxide concentration, the fatty acid zinc, zirconium alkoxide and / or aluminum alkoxide mixed solution does not dissolve the fatty acid zinc but exists as a solid dispersed or precipitated. Cannot be used.
By adding an appropriate amount of ethanolamine to this, all the fatty acid zinc is dissolved, and a homogeneous and stable transparent solution is obtained. If the amount of ethanolamine to be added is less than 0.7 (mol ratio) with respect to zinc fatty acid, the fatty acid zinc is not sufficiently dissolved, and undissolved fatty acid zinc particles are deposited during coating. Or. Also, the amount of ethanolamine added is 1.5 with respect to fatty acid zinc.
When it is more than the (mol ratio), the coating film becomes cloudy. Therefore, the addition amount of ethanolamine is preferably 0.7 to 1.5 (mol ratio) with respect to zinc fatty acid.
Zirconium alkoxides and / or aluminum alkoxides are very rapidly hydrolyzed and condensed, and if they are used as a coating solution as they are, the coating film will be rapidly hydrolyzed by moisture in the air during drying and will be whitened. . Therefore, it is difficult to prepare a coating solution using zirconium alkoxide or aluminum alkoxide. Therefore, Zr-O-Zr, Zr-O-Al, or Al- is used to gradually cause partial hydrolysis of alkoxide by using fatty acid zinc having water of crystallization as a zinc source.
The present inventors have succeeded in forming a partial inorganic polymer containing an O-Al bond, thereby reducing the amount of alkoxy groups hydrolyzed by moisture in the atmosphere, and solving the problem to reach the present invention. . Furthermore, ethanolamine substitutes or coordinates with the remaining alkoxy groups of zirconium alkoxide and / or aluminum alkoxide, prevents precipitation and turbidity of the film due to hydrolysis-condensation of the alkoxide, and improves the stability of the coating solution. Also plays a role.

Examples of ethanolamine to be added include monoethanolamine, diethanolamine, and triethanolamine, but monoethanolamine is preferable in view of boiling point, viscosity, and workability. Triethanolamine has a high boiling point and requires high temperature for drying the coating film. Further, since diethanolamine is in a solid state or a high viscosity state at room temperature, it is not preferable from the viewpoint of workability. Therefore, prepare the coating solution with good workability, and apply the coating film to
Monoethanolamine is most suitable for drying at a temperature of about 0 to 150 ° C.

Examples of the zirconium alkoxide used include tetraethoxyzirconium, tetranormalpropoxyzirconium, tetraisopropoxyzirconium, tetranormalbutoxyzirconium and tetraisobutoxyzirconium. Also, as the aluminum alkoxide, triethoxy aluminum,
Examples thereof include trinormal propoxy aluminum, triisopropoxy aluminum, trinormal butoxy aluminum and triisobutoxy aluminum. The solution obtained by the above-mentioned manufacturing method is the most suitable as a coating solution for forming a dense zinc oxide-based composite oxide film that absorbs ultraviolet rays.

As a method for applying the coating solution, spraying, roll coating, spin coating, dipping, printing and the like are excellent as methods for easily producing a uniform film. After forming a coating film on the surface of the glass substrate by the method described above, in order to remove the organic solvent, it is dried at 70 to 150 ° C. for 10 to 30 minutes and further baked at a temperature of 400 ° C. or higher for 10 to 30 minutes. In order to sufficiently absorb the ultraviolet rays and sufficiently increase the transmittance in the visible light region, the film thickness on one side is 0.5 to 2 μm, and the film thickness on one side is about 0.25 to 1 μm in the case of double side coating. preferable. By this method, ZnO, which has a higher surface hardness than a film of zinc oxide alone, is dense and has a high ultraviolet absorption capacity
The main component -ZrO ₂ based oxide, or ZnO-A
composed mainly of l ₂ O ₃ based oxide, or ZnO-Zr
A zinc oxide-based composite oxide film containing an O ₂ —Al ₂ O ₃ -based oxide as a main component is obtained.

The obtained zinc oxide-based composite oxide film is superior to the film of zinc oxide alone in terms of ultraviolet absorbing ability and surface hardness, but depending on the composition, a slight interference color is produced in the visible light region. In order to prevent the interference (reflection) of this light and further increase the visible light transmittance, an oxide film is formed on the obtained ultraviolet absorbing glass. When one or more oxide coatings of silica, alumina, and zirconia are formed on the ultraviolet absorbing glass, in addition to the effect of preventing visible light interference (reflection) and further improving the visible transmittance, it is also effective against acids and alkalis. It has been found that there is an advantage that chemical stability and durability against abrasion are further improved. In particular, coating an oxide film having a refractive index lower than that of the ultraviolet absorbing coating of the present invention on the ultraviolet absorbing film has a large effect of preventing reflection and improving the visible light transmittance. Alternatively, a composite oxide film in which zirconia is added to alumina is preferable. In addition, among oxide coatings containing at least one of silica, alumina and zirconia, those having a lower refractive index than the ultraviolet absorbing coating of the present invention are effective. Many of these oxide films have high chemical resistance and high hardness, and the surface hardness and chemical resistance of the ultraviolet absorbing film are simultaneously improved.

As a method for forming an oxide coating on the ultraviolet absorbing glass obtained by the present invention, Si, Al, Z
r or their physical film-forming methods such as vacuum deposition, ion plating, sputtering, reactive sputtering, chemical film-forming methods such as CVD, MOCVD and plasma CVD, spraying of metal salts, metal alkoxide solutions, etc., roll coating Coating by spin coating, dipping, printing, etc.,
Examples include, but are not limited to, oxidative pyrolysis. Of these, coating and oxidative pyrolysis are the easiest and cheapest methods, and are therefore very preferable in view of economic efficiency, mass production, coating on a large area glass, and the like.

The coating liquid used in this coating method is Si, A
The alkoxide of 1, Zr or the alkoxy group of the alkoxide is partially substituted with a chlorine or alkyl group, or an acetoxy group, or prepared from a salt of each metal.
In the case of using i alkoxide, Na, K, Ca, Al, B, Z are used as modifiers in order to facilitate glass formation.
It can also be prepared by adding an alkoxide such as r or Pb or an inorganic salt. Specifically, examples of the raw material of Si include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, and dimethyldiethoxysilane.

Examples of the raw material of alumina include triethoxyaluminum, trinormalpropoxyaluminum, triisopropoxyaluminum, trinormalbutoxyaluminum, triisobutoxyaluminum and the like. Examples of raw materials for zirconia include tetraethoxyzirconium, tetranormalpropoxyzirconium, tetraisopropoxyzirconium, tetranormalbutoxyzirconium and tetraisobutoxyzirconium.

The concentration of the coating liquid for forming the oxide film provided on the ultraviolet absorbing glass is preferably 0.1 to 2 mol / l in terms of the concentration of the metal component in the solution. This is 0.1 mol
If the concentration is lower than 1 / l, the thickness of the film that can be formed by one coating operation will be extremely thin, and the effect of preventing light interference (reflection) and improving visible light transmittance, abrasion resistance, and chemical resistance will be improved. I can't get enough. The coating operation must be repeated many times in order to form a film which exerts a sufficient effect with the coating solution having such a low concentration, which is very unfavorable for practical use because productivity is very poor. When the concentration of the coating liquid is 2 mol / l or more, the coating film is whitened or cracks occur. Therefore,
0.1 to 2 mol / l is preferable.

The thickness of the coating film formed using this coating solution is preferably about 0.1 to 2 μm. If the thickness is less than 0.1 μm, the effects of preventing light interference (reflection) and improving visible light transmittance, abrasion resistance, and chemical resistance cannot be sufficiently obtained. vice versa,
A film thicker than 2 μm is not preferable because the transmittance of visible light becomes worse.

The method for forming the oxide film on the ultraviolet absorbing glass is as described above by spraying the coating solution, roll coating,
70 to 1 after applying by spin coating, dipping, etc.
Dry at 50 ° C for 10 to 30 minutes, 10 at 400 ° C or higher
Bake for ~ 30 minutes. By this operation, it is possible to form an oxide film having the effect of preventing interference (reflection) and the effect of improving visible light transmittance, abrasion resistance and chemical resistance on the ultraviolet absorbing glass of the present invention, which is excellent. It becomes UV absorbing glass.

As described above, since the ultraviolet absorbing glass obtained in the present invention has excellent ultraviolet absorbing ability and durability,
Wide range in the optical glass field such as glass for automobiles, ships, railway vehicles, headlights for automobiles, lamps, lighting equipment, interior decoration glass for showcases, window glass for buildings, glasses, sunglasses, lenses, etc. It is thought to have various uses.

[0023]

Example 1 Zinc acetate (first-class reagent, Fe as an impurity,
0.58 mol (including Pb, As, etc.), tetra-normal propoxyzirconium (reagent grade, Hf as an impurity,
Fe, Si, Al, etc.) 0.25 mol and triisopropoxyaluminum (special grade reagent) 0.006 m
is mixed in 430 ml of normal propyl alcohol (special grade reagent, including water) and stirred, and 0.45 mol of monoethanolamine (special grade reagent, including water) is added to the mixture.
And mix for 1 hour. A slide glass was immersed in the coating solution for forming a zinc oxide-based complex oxide film thus prepared, and pulled up at a speed of 48 cm / min to form a coating film. This coating film is dried at 150 ° C. for 10 minutes to remove the organic solvent and cure the film, and then 50 in an electric furnace.
It was baked at 0 ° C. for 30 minutes to obtain a uniform zinc oxide-based composite oxide film having a thickness of 0.35 μm on one surface. The light transmittance characteristics of the ultraviolet absorbing glass of this example are shown in FIG. 370n
It can be seen that almost all light having a wavelength of m or less is absorbed, and excellent transmission characteristics are exhibited in the visible light region. A cross-cut tape test was conducted to examine the adhesion of the obtained ultraviolet absorbing film. The result was 100/100, and it was found that the film had no peeling and had good adhesion.

[0024]

Example 2 Zinc acetate 0.58 mol, triisopropoxy aluminum 0.25 mol and isopropanol 5
Mix and stir in 00 ml, add 0.45 mol of monoethanolamine to the mixture, and mix for 1 hour. A slide glass was dipped in the coating liquid for forming a zinc oxide-based complex oxide film thus prepared, and pulled up at a speed of 24 cm / min to form a coating film. This coating film is 150 ℃
After 10 minutes of drying to remove the organic solvent and cure the film, it is baked in an electric furnace at 500 ° C. for 30 minutes to form a uniform zinc oxide-based composite oxide film having a thickness of 0.25 μm on one side. Obtained. The light transmittance characteristics of the ultraviolet absorbing glass of this example are shown in FIG. As in Example 1, it is understood that almost all light having a wavelength of 370 nm or less is absorbed and excellent transmission characteristics are shown in the visible light region.

[0025]

Examples 3 to 6 The coating solutions shown in Table 1 were applied to the ultraviolet absorbing glass having the zinc oxide-based composite oxide coating obtained in Example 1 by the dipping method. Lifting speed is 24 cm /
min, dry at 150 ° C for 10 minutes, then 500 ° C
And baked for 30 minutes. By this operation, an oxide film having a film thickness shown in Table 1 was formed on the ultraviolet absorbing glass. The light transmission characteristics of the ultraviolet absorbing glasses obtained in Examples 3 and 4 are shown in FIGS. 3 and 4. Compared with Example 1, the ultraviolet absorption ability at 370 nm or less is almost the same, but the visible light transmittance is considerably improved and shows a high value, and the degree of light interference is reduced, and the transparency is high. It became UV absorbing glass. Also in Example 5 and Example 6, an ultraviolet absorbing glass having similar optical characteristics was obtained.

Further, the ultraviolet absorbing glass obtained as shown in Table 1 was tested for chemical stability and adhesion. Comparative Example 1 is the ultraviolet absorbing glass itself obtained in Example 1, which is not coated with anything. In the acid resistance test, the sample was immersed in a 1% hydrochloric acid aqueous solution at 35 ° C. for 1 hour, and changes in light absorption characteristics before and after immersion were examined. In the alkali resistance test, the sample was immersed in a 1% aqueous sodium hydroxide solution at 35 ° C. for 1 hour, and the change in light absorption characteristics before and after the immersion was examined. For the adhesion test, a 1 mm square cross-cut tape test was conducted to examine the degree of peeling.

From the results of the above Examples and Comparative Examples, the ultraviolet absorbing glass having an oxide coating on the surface thereof has a higher visible light transmittance and transparency than the ultraviolet absorbing glass having only the zinc oxide type composite oxide coating. Furthermore, it has been revealed that it is excellent in terms of chemical durability.

[0028]

EFFECT OF THE INVENTION The coating solution for forming a zinc oxide-based complex oxide film of the present invention absorbs only light in the ultraviolet region by coating, drying and baking on a glass substrate, and with respect to light in the visible light region. It is a dense film having excellent optical characteristics such as high transmission characteristics. Therefore, according to the present invention, it becomes possible to easily manufacture an ultraviolet absorbing glass which is very inexpensive to manufacture. Furthermore, by forming at least one oxide film of silicon, aluminum, or zirconium on the ultraviolet absorbing glass, the transparency and visible light transmittance are further improved, and the ultraviolet absorption is also excellent in chemical durability. It becomes glass.

[0029]

[Table 1]

[Brief description of drawings]

FIG. 1 is a diagram showing a light transmittance characteristic of each ultraviolet absorbing glass obtained in Example 1 of the present invention as a graph in comparison with a glass substrate.

FIG. 2 is a diagram showing the light transmittance characteristics of each ultraviolet absorbing glass obtained in Example 2 of the present invention as a graph in comparison with a glass substrate.

FIG. 3 is a graph showing the light transmittance characteristics of each ultraviolet absorbing glass obtained in Example 3 of the present invention in comparison with a glass substrate.

FIG. 4 is a graph showing a light transmittance characteristic of each ultraviolet absorbing glass obtained in Example 4 of the present invention in comparison with a glass substrate.

Claims (3)

(57) [Claims] 1. A fatty acid of the formula Zn (OCOR) ₂ .xH ₂ O (wherein x represents the number of water of crystallization, and R represents a linear or branched alkyl group having 1 to 8 carbon atoms). Zinc and ethanolamine in a mole ratio of 0.7 to 1.5 per mole thereof;
The formula Zr (O
R ′) ₄ (wherein R ′ represents a linear or branched alkyl group having 1 to 4 carbon atoms) zirconium alkoxide,
And / or a zinc oxide-based composite oxide ultraviolet absorbing film composed of an aluminum alkoxide of the formula Al (OR ″) ₃ (wherein R ″ represents a linear or branched alkyl group having 1 to 4 carbon atoms) Forming coating liquid. 2. A zirconium alkoxide of the formula Zr (OR ′) ₄ (wherein R ′ represents a straight-chain or branched alkyl group having 1 to 4 carbon atoms) and / or a formula Al (O
R ″) ₃ (in the formula, R ″ represents a linear or branched alkyl group having 1 to 4 carbon atoms) and a formula Zn (OCOR) ₂ · xH ₂ O) (in the formula, x Represents the number of water of crystallization, and R represents a straight chain or branched chain alkyl group having 1 to 8 carbon atoms) in an organic solvent to partially hydrolyze / depolymerize the metal alkoxide. A method for producing a coating solution for forming a zinc oxide-based complex oxide ultraviolet absorbing film, which comprises condensing and adding ethanolamine to form a transparent solution. 3. A fatty acid of the formula Zn (OCOR) ₂ .xH ₂ O (wherein x represents the number of crystal water, and R represents a linear or branched alkyl group having 1 to 8 carbon atoms). Zinc and ethanolamine in a mole ratio of 0.7 to 1.5 per mole thereof;
The formula Zr (O
R ′) ₄ (wherein R ′ represents a linear or branched alkyl group having 1 to 4 carbon atoms) zirconium alkoxide,
And / or a zinc oxide-based composite oxide ultraviolet absorbing film composed of an aluminum alkoxide of the formula Al (OR ″) ₃ (wherein R ″ represents a linear or branched alkyl group having 1 to 4 carbon atoms) After coating the coating solution for formation on a glass substrate and drying it, at least one of silicon, aluminum, and zirconium is oxidized on the ultraviolet absorbing glass coated with a zinc oxide-based complex oxide film by firing at 400 ° C or higher. An ultraviolet absorbing glass on which a film made of a material is formed.