JP2000204282A - Coating liquid for forming low-transmittance transparent layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating liquid for forming low-transmittance transparent layers which imparts a good antireflection effect and forms a low-transmittance transparent layer exerting a good transmitted light ray profile within the visible light range, film strength and weather resistance when applied to a front plate of display devices such as cathode-ray tubes. SOLUTION: The coating liquid essentially comprises a solvent, a carbon fine particle having an average particle size of from 10 to 150 nm and a black titanium compound fine particle having an average particle size of from 10 to 150 nm which are dispersed in this solvent. Here, the mixing ratio of the carbon fine particles to the black titanium compound is from 80 to 2,500 pts.wt. black titanium compound against 100 pts.wt. carbon fine particles. A low- transmittance transparent layer formed with this coating liquid consists of a carbon fine particle having an average particle size of from 10 to 150 nm and a black titanium compound fine particle having an average particle size of from 10 to 150 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating liquid for forming a low transmittance transparent layer for forming a low transmittance transparent layer on a transparent substrate, and more particularly to a front plate of a display device such as a cathode ray tube (CRT). When applied to a low transmittance transparent layer, it can provide a good antireflection effect and contrast improving effect, and can form a low transmittance transparent layer with good transmission light profile in the visible light range, weather resistance, and film strength. It relates to a coating liquid for use.

[0002]

2. Description of the Related Art With the recent trend toward office automation in offices, the number of opportunities to work in contact with a cathode ray tube (CRT) display of a computer has been increasing. It is demanded that the user does not feel any. Similarly, home color televisions are also required to be easily viewable on display screens.

In order to satisfy these requirements, the transmittance of the front glass of the CRT is lowered to improve the contrast, and in order to make the display screen easier to see, the face panel surface is subjected to an anti-glare treatment to suppress the reflection of the screen. Has also been done.

[0004] For example, this anti-glare treatment is also performed by a method of increasing the diffuse reflection of the surface by providing fine irregularities. However, when this method is used, it is not preferable because the resolution is reduced and the image quality is reduced. I can't say.

Therefore, it is preferable to perform anti-glare treatment by an interference method for controlling the refractive index and the thickness of the transparent film so that the reflected light causes destructive interference with the incident light.

In order to obtain a low reflection effect by such an interference method, generally, the optical film thicknesses of the high refractive index film and the low refractive index film are set to １ ／ λ and ４λ, and λλ and ４λ ( λ: wavelength)
Is generally adopted.

In order to meet the above demand, a coating liquid in which carbon fine particles are dispersed in a solvent is applied to the front glass of a CRT, dried, and then overcoated with a coating liquid mainly composed of silica sol or the like. Baking at a temperature of about ℃,
A method for forming a low transmittance transparent layer is known.

This method is much simpler than other methods of forming a low-transmittance transparent layer such as vacuum evaporation and sputtering.
The manufacturing cost is low, and a film with low reflectance can be obtained.

However, as shown in Comparative Examples 1 and 2 in FIG. 2, there is a problem that the transmission profile of the film decreases on the short wavelength side of visible light, and the transmission color becomes brownish.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. An object of the present invention is to provide a good anti-reflection when applied to a front panel of a display device such as a CRT. An object of the present invention is to provide a coating liquid for forming a low-transmittance transparent layer capable of forming a low-transmittance transparent layer having a transmission light profile in the visible light region, weather resistance and film strength, which imparts an effect and a contrast improving effect.

[0011]

That is, the invention according to claim 1 is based on a premise that a low transmittance transparent layer forming coating liquid for forming a low transmittance transparent layer on a transparent substrate is used, and a solvent and this solvent The main component is carbon fine particles having an average particle diameter of 10 to 150 nm and black titanium compound fine particles having an average particle diameter of 10 to 150 nm, and the mixing ratio of the carbon fine particles and the black titanium compound is 100 parts by weight of the carbon fine particles. The compound is set in the range of 80 to 2500 parts by weight, and the invention according to claim 2 is based on the premise of the low transmittance transparent layer forming coating solution according to the invention according to claim 1, The black titanium compound is black titanium oxide or black titanium oxynitride. Next, the invention according to claim 3 is a low transmittance transparent article according to claim 1 or 2. It assumes layer forming coating liquid, and is characterized in that it contains an inorganic binder.

The invention according to claim 4 is based on the premise of the coating liquid for forming a low transmittance transparent layer according to the invention according to claim 1, 2 or 3, wherein the inorganic binder is mainly composed of silica sol. And

[0013]

Embodiments of the present invention will be described below in detail.

First, the present invention provides a low transmittance transparent layer using carbon fine particles alone or black titanium compound fine particles alone when a coating liquid for forming a low transmittance transparent layer in which carbon fine particles and black titanium compound fine particles are mixed is used. The above-mentioned problems have been solved based on the idea that a film having more excellent flatness of the transmission profile can be obtained as compared with the case of the coating liquid for forming.

As shown in Comparative Examples 1 and 2 in FIG. 2, the transmission color of the film becomes brownish when the coating liquid for forming the transparent layer containing the carbon fine particles is used, and the low transmission containing the black titanium compound fine particles is used. The explanation is based on the result that when the coating liquid for forming a transparent layer is used, it is bluish.

Although the optical constants (n-ik, n: refractive index, k: extinction coefficient) of the carbon fine particles and the black titanium compound fine particles are not clear, the coating liquid for forming a transparent layer having a low transmittance according to the present invention is used. A transparent low-transmittance layer composed of carbon fine particles and black titanium compound fine particles is formed on a transparent substrate, and then a transparent coat layer containing silicon oxide as a main component is formed using a coating liquid for forming a transparent coat layer. In the low-transmittance transparent substrate provided with the two-layer film described above, good low-reflection characteristics can be obtained.

Here, the carbon fine particles and the black titanium compound fine particles in the coating liquid for forming a low transmittance transparent layer in the present invention are required to have an average particle diameter of 10 to 150 nm, respectively.

If it is less than 10 nm, it is difficult to produce these fine particles, and at the same time, it is not easy to disperse in making a coating material, which is not practical.

On the other hand, if it exceeds 150 nm, visible light scattering of the formed low transmittance transparent layer increases, that is, the haze value of the film increases, which is not practical.

Incidentally, the average particle size here indicates the average particle size of the fine particles observed by a transmission electron microscope (TEM).

Next, the blending ratio of the carbon fine particles and the black titanium compound in the coating liquid for forming the low transmittance transparent layer is such that the black titanium compound is 80 parts by weight with respect to 100 parts by weight of the carbon fine particles.
It is desirably set in the range of ２2500 parts by weight (claim 1), preferably in the range of 100-2000 parts by weight.

If the compounding ratio of the black titanium compound is less than 80 parts by weight or more than 2500 parts by weight, the flatness of the transmission profile of the formed low-transmittance transparent layer deteriorates.

As the black titanium compound, black titanium oxide or black titanium oxynitride is used.

The black titanium oxide is, for example, low-order titanium oxide (TiO _2-x ) obtained by treating titanium oxide (TiO ₂ ) at a high temperature in a hydrogen atmosphere, and the black titanium oxynitride is titanium oxide (TiO ₂ ). ₂ ) a nitrogen-containing titanium compound (T) obtained by treating at a high temperature in an ammonia atmosphere.
i _X O _Y N _Z ).

Next, the coating liquid for forming a low transmittance transparent layer according to the present invention can be produced by the following method.

That is, the carbon fine particles and the black titanium compound fine particles are mixed with a dispersant and a solvent, and subjected to a dispersion treatment using a dispersing device such as a paint shaker, a sand mill, or an ultrasonic disperser to a dispersion particle size of about 50 to 180 nm. After obtaining a homogeneous dispersion, it is obtained by diluting it with a solvent. If necessary, a binder component such as silica sol may be added before or after the dispersion treatment step.

The solvent is not particularly limited.
It is appropriately selected depending on the coating method and film forming conditions. For example, water, methanol, ethanol, isopropanol,
Alcohol solvents such as butanol, benzyl alcohol, diacetone alcohol, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK),
Ketone solvents such as cyclohexanone and isophorone, glycol derivatives such as propylene glycol methyl ether and propylene glycol ethyl ether, dimethylformamide (DMF), N-methyl-2-pyrrolidone (N
MP) and the like, but are not limited thereto.

Next, using the thus-obtained coating liquid for forming a low-transmittance transparent layer according to the present invention, a transparent substrate and an average particle size of 10 to 150 nm formed on the transparent substrate are prepared.
A low-transmittance transparent base material whose main part is composed of a low-transmittance transparent layer containing m and a binder matrix as main components and a transparent two-layer film composed of a transparent coat layer formed thereon is obtained. be able to.

Then, on the transparent substrate, the low transmittance transparent 2
This can be done in the following manner to form a layer film.

That is, the solvent and the average particle size are 10 to 150 n.
m, carbon fine particles and a black titanium compound fine particle having an average particle diameter of 10 to 150 nm as main components, a low transmittance transparent layer forming coating liquid according to the present invention, spray-coated on a transparent substrate such as a glass substrate or a plastic substrate, The composition is applied by a method such as spin coating, wire bar coating, doctor blade coating and the like, dried if necessary, and then overcoated with a coating liquid for forming a transparent coating layer containing, for example, silica sol or the like as a main component.

Next, after overcoating, for example, 50
The coating liquid for forming a transparent coat layer, which has been subjected to a heat treatment at a temperature of about 500 ° C. and is overcoated, is cured to form the low transmittance transparent two-layer film.

Here, when the coating solution for forming a transparent coat layer mainly composed of silica sol or the like is overcoated by the above-described method, a low-permeability mainly composed of a previously applied solvent, carbon fine particles and black titanium compound fine particles. An overcoated silica sol solution (this silica sol solution becomes a binder matrix containing silicon oxide as a main component by the above heat treatment) is provided between the carbon fine particles and the black titanium compound fine particle layer formed by the coating liquid for forming the transparent transparent layer. By soaking, improvement in strength and weather resistance is achieved at the same time.

Further, the optical constant (n) of the low transmittance transparent layer in which carbon fine particles and black titanium compound fine particles are dispersed in the above binder matrix containing silicon oxide as a main component.
-Ik), the refractive index n and the extinction coefficient k are not clear, but the low transmittance transparent two-layer film structure of the low transmittance transparent layer and the transparent coat layer makes the reflectance of the low transmittance transparent two-layer film. Can be greatly reduced.

As shown in FIG. 1, the carbon fine particles and the black titanium compound fine particles (Example 1) were compared with the case where carbon fine particles (Comparative Example 1) and titanium oxynitride fine particles (Comparative Example 2) were applied. When 1) is used, equivalent or better reflection characteristics can be obtained.

Further, as shown in FIG. 2, the transmitted light profile of the low transmittance transparent two-layer film is also improved by using both carbon fine particles and black titanium compound fine particles.

For example, in the visible light wavelength range (380 to 780)
The standard deviation of the transmittance of only the low transmittance transparent two-layer film not containing the transparent substrate at each wavelength of 5 nm (comparative example 1) or black titanium compound fine particles (Comparative example) 4-9% when using 2)
However, when carbon fine particles and black titanium compound fine particles were used (Examples 1 to 4), the value was as small as about 1 to 3%, and a very flat transmission profile was obtained.

Here, as the silica sol, an orthoalkyl silicate is hydrolyzed by adding water or an acid catalyst,
Utilize a polymer that has undergone dehydration polycondensation, or a commercially available alkyl silicate solution that has already undergone hydrolysis and polycondensation to a tetramer to a polymer that has undergone further hydrolysis and dehydration polycondensation. be able to.

As the dehydration-condensation polymerization progresses, the solution viscosity increases and eventually solidifies. Therefore, the degree of dehydration-condensation polymerization can be applied to a transparent substrate such as a glass substrate or a plastic substrate. Adjust to below the upper limit viscosity.

The degree of dehydration polycondensation is not particularly specified as long as it is at or below the above-mentioned upper limit viscosity. However, considering the film strength and weather resistance, the weight-average molecular weight is 500 to 3,000.
The degree is preferred.

The alkyl silicate partially hydrolyzed polymer almost completes the dehydration-condensation polymerization reaction during heating and sintering of the low-transmittance transparent two-layer film to form a hard silicate film (a film mainly composed of silicon oxide). .

Incidentally, it is also possible to add the magnesium fluoride fine particles, alumina sol, titania sol, zirconia sol, etc. to the above silica sol and adjust the refractive index of the transparent coat layer to change the reflectivity of the low transmittance transparent two-layer film. is there.

Further, a solvent and carbon fine particles having an average particle diameter of 10 to 150 nm dispersed in the solvent and an average particle diameter of 10 to 150 nm are used.
In addition to the 150 nm black titanium compound fine particles, a silica sol solution as an inorganic binder component constituting the binder matrix of the low transmittance transparent layer may be blended to form the low transmittance transparent layer forming coating liquid according to the present invention. (Claims 3 and 4). Also in this case, by applying a coating liquid for forming a low-transmittance transparent layer containing a silica sol liquid and, if necessary, drying, and then overcoating the coating liquid for forming a transparent coat layer by the above-described method, A similar low transmittance transparent two-layer film is obtained.

As described above, the transparent conductive substrate provided with the low-transmittance transparent layer formed by applying the low-transmittance transparent layer forming coating solution according to the present invention has a higher transmittance than the conventional one. Has a light profile and an excellent anti-reflection effect, and
Since it has good film strength and weather resistance, it can be used for, for example, a front plate of a display device such as a CRT described above.

[0044]

EXAMPLES Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.
Further, “%” in the text indicates “% by weight” excluding (%) of transmittance, reflectance, and haze value, and “part” indicates “part by weight”.

Example 1 Titanium hydroxide obtained by hydrolyzing titanium chloride with an aqueous alkali solution was treated at 800 ° C. in ammonia gas to obtain black titanium oxynitride fine particles (nitrogen: 15.5%). Obtained.

After mixing 8 g of the black titanium oxynitride fine particles and 7 g of the dispersant with 65 g of pure water, the mixture was dispersed with a zirconia bead in a paint shaker to give a dispersion particle diameter of 135 nm.
To obtain a black titanium oxynitride fine particle dispersion (Solution A).

Next, after mixing 8 g of carbon fine particles (MA7, manufactured by Mitsubishi Chemical Corporation) and 1.2 g of dispersant with 70.8 g of isopropyl alcohol (IPA), the mixture was dispersed with a zirconia bead in a paint shaker to obtain a dispersion particle size. A 100 nm carbon fine particle dispersion (solution B) was obtained. A
Add 0.60 g of Liquid B and 0.32 g of Liquid B to ethanol (E
A), isopropyl alcohol (IPA), and propylene glycol monomethyl ether (PGM) were added, and a coating liquid for forming a low transmittance transparent layer containing carbon fine particles and black titanium compound fine particles according to Example 1 (carbon: 0.16%, black) Titanium oxynitride: 0.30%, water: 2.44%, EA:
55.59%, IPA: 11.23%, PGM: 30.0
%).

As a result of observing the obtained coating liquid containing the fine carbon particles and the fine black titanium compound particles with a transmission electron microscope, the average particle diameter of the fine carbon particles and the fine black titanium compound particles was as follows:
They were 40 nm and 55 nm, respectively.

Next, the coating liquid for forming a low-transmittance transparent layer containing the carbon fine particles and the black titanium compound fine particles was spin-coated (150 rpm, 150 rpm) on a glass substrate (soda-lime glass having a thickness of 3 mm) heated to 40 ° C. After 120 seconds, the silica sol solution is spin-coated (150 r).
pm, 60 seconds) and further cured at 180 ° C. for 30 minutes to form a low transmittance transparent layer containing carbon fine particles and black titanium compound fine particles, and a transparent coat layer composed of a silicate film containing silicon oxide as a main component. , Ie, a low-transmittance transparent substrate according to Example 1.

The silica sol solution used herein was 19.6 parts of methyl silicate 51 (trade name, manufactured by Colcoat), 57.8 parts of ethanol, 7.9 parts of a 1% aqueous nitric acid solution, and 1 part of pure water.
Using 4.7 parts, a solid having a SiO ₂ (silicon oxide) solid concentration of 10% was prepared, and finally, isopropyl alcohol (I) was adjusted so that the SiO ₂ solid concentration became 1.0%.
PA) and a mixture of n-butanol (NBA) (IPA /
NBA = 3/1).

Table 1 below shows the film properties (surface resistance, transmittance, standard deviation of transmittance, haze value, bottom reflectance / bottom wavelength) of the two-layer film formed on the glass substrate.

The above-mentioned bottom reflectance means a minimum reflectance in a reflection profile of a low transmittance transparent base material,
The bottom wavelength means a wavelength at which the reflectance is minimal.

FIG. 1 and FIG. 3 show reflection profiles of the manufactured low-transmittance transparent substrate according to Example 1.
The transmission profile is shown in FIG. 2 and FIG.

In Table 1, the visible light wavelength range (380
The transmittance of only the two-layer film not including the transparent substrate (glass substrate) at each wavelength of 5 nm (to 780 nm) is determined as follows. That is, the transmittance (%) of only the two-layer film not including the transparent substrate = [(the transmittance measured for each transparent substrate) / (the transmittance of the transparent substrate)]
× 100 In this specification, the transmittance and the transmission profile of only the low-transmittance transparent film that does not include the transparent substrate are used as the transmittance and the transmission profile unless otherwise specified.

The haze value and visible light transmittance of each transparent substrate were measured using a haze meter (HR-20, manufactured by Murakami Color Research Laboratory).
0).

The reflectivity and the reflection / transmission profile are as follows:
The measurement was performed using a spectrophotometer (U-4000) manufactured by Hitachi, Ltd.

The particle size of the fine particles in the dispersion is measured by a laser scattering particle size analyzer (ELS-800) manufactured by Otsuka Electronics Co., Ltd.
The particle diameters of the carbon fine particles and the black titanium compound fine particles were evaluated with a transmission electron microscope manufactured by JEOL.

Example 2 0.45 g of solution A and 0.4 g of solution B
08 g of the coating liquid for forming the low transmittance transparent layer containing the carbon fine particles and the black titanium compound fine particles according to Example 2 (carbon: 0.08%, black titanium oxynitride: 0.45%,
Water: 3.66%, EA: 55.0%, IPA: 10.4
(1%, PGM: 30.0%) except that a low transmittance transparent layer containing fine carbon particles and black titanium compound fine particles and a silicate film containing silicon oxide as a main component were obtained. , A glass substrate with a two-layer film composed of a transparent coat layer made of, that is, a low-transmittance transparent substrate according to Example 2.

The film characteristics of the two-layer film formed on the glass substrate are shown in Table 1 below. FIG. 5 shows the reflection profile of the manufactured low-transmittance transparent substrate according to Example 2.
FIG. 6 shows the transmission profile.

Example 3 Black titanium oxide (Tila)
After mixing 8 g of ckD (manufactured by Ako Kasei Co., Ltd.) and 3.2 g of a dispersant with 68.8 g of diacetone alcohol (DAA), the mixture was dispersed with a zirconia bead in a paint shaker, and a black titanium oxide fine particle dispersion having a particle diameter of 125 nm was dispersed. (Liquid C), and using 1.8 g of Liquid C and 0.08 g of Liquid B, a coating liquid for forming a low transmittance transparent layer containing carbon fine particles and black titanium compound fine particles according to Example 3 (carbon:
0.08%, black titanium oxide: 1.80%, EA: 4
3.52%, IPA: 8.39%, DAA: 15.48
%, PGM: 30.0%), except that a low transmittance transparent layer containing carbon fine particles and black titanium compound fine particles and a silicate film containing silicon oxide as a main component were obtained. Thus, a glass substrate with a two-layer film composed of a transparent coat layer and a low transmittance transparent substrate according to Example 3 was obtained.

The film characteristics of the two-layer film formed on the glass substrate are shown in Table 1 below. FIG. 7 shows the reflection profile of the manufactured low-transmittance transparent substrate according to Example 3.
FIG. 8 shows the transmission profile.

Example 4 0.3 g of solution A of Example 1
And SiO ₂ (silicon oxide) prepared using 19.6 parts of methyl silicate 51 (trade name, manufactured by Colcoat), 70.3 parts of ethanol, 7.9 parts of 1% nitric acid aqueous solution, and 2.2 parts of pure water. 0.46 silicate solution with a solid content of 10%
g, and a coating liquid for forming a low transmittance transparent layer containing carbon fine particles and black titanium compound fine particles according to Example 4 (carbon: 0.16%, black titanium oxynitride: 0.30%, Si
O ₂ : 0.46%, water: 2.90%, EA: 54.91
%, IPA: 10.54%, PGM: 30.0%), except that a low-transmittance transparent layer containing carbon fine particles and black titanium compound fine particles, and silicon oxide were formed. A glass substrate with a two-layer film composed of a transparent coat layer composed of a silicate film as a main component, that is,
A low transmittance transparent substrate according to Example 4 was obtained.

Table 1 below shows the film characteristics of the two-layer film formed on the glass substrate. FIG. 9 shows the reflection profile of the manufactured low-transmittance transparent substrate according to Example 4, and FIG. 10 shows the transmission profile.

Comparative Example 1 In Example 1, carbon fine particles (MA-7, manufactured by Mitsubishi Chemical Corporation) were used instead of carbon fine particles and black titanium compound fine particles, and carbon fine particles having an average particle size of 40 nm were dispersed. The coating liquid for forming a low transmittance transparent layer containing carbon fine particles according to Comparative Example 1 (carbon: 0.32%, EA: 56.78%, IPA: 11.2%).
95%, PGM: 30.0%), except that a low transmittance transparent layer containing carbon fine particles and a transparent coat layer composed of a silicate film containing silicon oxide as a main component were obtained. , That is, a low-transmittance transparent substrate according to Comparative Example 1.

Table 1 shows the film characteristics of the two-layer film formed on the glass substrate. FIG. 1 shows a reflection profile of the manufactured low transmittance transparent substrate according to Comparative Example 1.
FIG. 2 shows the transmission profile.

Comparative Example 2 The black titanium oxynitride fine particles used in Example 1 were used instead of the carbon fine particles and the black titanium compound fine particles in Example 1, and the average particle diameter was 55 n.
m black titanium oxynitride fine particles dispersed therein, and a coating liquid for forming a low transmittance transparent layer containing black titanium oxynitride fine particles according to Comparative Example 2 (black titanium oxynitride fine particles: 0.60%, water: 4.88)
%, EA: 54.40%, IPA: 9.60%, PGM:
30.0%), except that a low transmittance transparent layer containing black titanium oxynitride fine particles and a transparent coat layer composed of a silicate film containing silicon oxide as a main component were used. A glass substrate with a two-layer film, that is, a low-transmittance transparent substrate according to Comparative Example 2 was obtained.

The film characteristics of the two-layer film formed on the glass substrate are shown in Table 1 below. FIG. 1 shows a reflection profile of the manufactured low transmittance transparent substrate according to Comparative Example 1.
FIG. 2 shows the transmission profile.

Comparative Example 3 0.15 g of solution A and 0.15 g of solution B
Using 24 g, a coating liquid for forming a low transmittance transparent layer containing carbon fine particles and black titanium compound fine particles according to Comparative Example 3 (carbon: 0.24%, black titanium oxynitride: 0.15%,
Water: 1.22%, EA: 56.19%, IPA: 12.
04%, PGM: 30.0%), except that a low transmittance transparent layer containing fine carbon particles and fine black titanium compound particles, and a silicate film containing silicon oxide as a main component were obtained. 2 composed of a transparent coat layer composed of
A glass substrate with a layer film, that is, a low-transmittance transparent substrate according to Comparative Example 3 was obtained.

Table 1 below shows the film properties of the two-layer film formed on the glass substrate. FIG. 1 shows the reflection profile of the manufactured low-transmittance transparent substrate according to Comparative Example 3.
1 and the transmission profile is shown in FIG.

Comparative Example 4 The procedure of Example 1 was repeated, except that the transparent coat layer composed of a silicate film containing silicon oxide as a main component was not formed. Glass substrate with a single layer film composed of a low transmittance transparent layer containing fine particles, that is,
A low-transmittance transparent substrate according to Comparative Example 4 was obtained.

Table 1 below shows the film characteristics of the single-layer film formed on the glass substrate. FIG. 1 shows the reflection profile of the manufactured low-transmittance transparent substrate according to Comparative Example 4.
3 and the transmission profile is shown in FIG.

[0072]

[Table 1]

Note 1: Parts by weight of carbon / parts by weight of black titanium compound. Note 2: 5 nm in the visible light wavelength range (380 to 780 nm)
It is a value for the transmittance (%) of only the two-layer film not including the transparent substrate at every other wavelength.

"Weather Resistance Test" The low transmittance transparent base materials according to Examples 1 to 4 were immersed in a 10% aqueous saline solution, a 50% aqueous acetic acid solution, and a 5% aqueous ammonia solution for 24 hours to form a transparent substrate (glass substrate). The transmittance and appearance of the film provided thereon were examined, but no change was observed.

[Film Strength Test] The low transmittance transparent base materials according to Examples 1 to 4 and Comparative Example 4 were subjected to a pencil hardness test (load 1 k
g). Table 2 shows the results.

[0076]

[Table 2]

“Evaluation” (1) As is clear from the results shown in Table 1, the value of the standard deviation of the transmittance of the two-layered film according to each example was determined in Comparative Example 1.
It is confirmed that the values are improved as compared with the values of the two-layer films according to Nos. 1 to 3. As is clear from the comparison between the transmission profile of the low transmittance transparent substrate according to Example 1 and the transmission profile of the low transmittance transparent substrate according to Comparative Example 1 or Comparative Example 2 shown in FIG. It is also confirmed that the low transmittance transparent base material of Example 1 has a very flat transmission profile. Further, as is apparent from the reflection profile of FIG. 1, compared to Comparative Examples 1 and 2, the low-transmittance transparent substrate according to Example 1 has a reflection characteristic in the visible light wavelength region that is equal to or higher than that of Comparative Example 1. It is confirmed that it is done. (2) Further, as is clear from the results shown in Table 2, it is confirmed that the film strength of the two-layer film according to each example is significantly superior to the single-layer film according to Comparative Example 4. .

[0078]

According to the coating liquid for forming a transparent layer having a low transmittance according to the present invention, a solvent, carbon fine particles having an average particle size of 10 to 150 nm dispersed in the solvent and an average particle size of 10 As the main component is black titanium compound fine particles of ~ 150 nm, the mixing ratio of carbon fine particles and black titanium compound is set in the range of 80 to 2500 parts by weight of black titanium compound with respect to 100 parts by weight of carbon fine particles.
Compared with the low transmittance transparent layer to which the conventional low transmittance transparent layer forming coating liquid has been applied, it has a flatter transmission light profile in the visible light region, and has good film strength, weather resistance, and anti-reflection effect. This has the effect of forming a transparent layer having a low transmittance.

[Brief description of the drawings]

FIG. 1 is a graph showing a reflection profile of a low-transmittance transparent substrate according to Example 1 and Comparative Examples 1 and 2.

FIG. 2 is a graph showing a transmission profile of a low transmittance transparent base material according to Example 1 and Comparative Examples 1 and 2.

FIG. 3 is a graph showing a reflection profile of a low transmittance transparent substrate according to Example 1.

FIG. 4 is a graph showing a transmission profile of a low-transmittance transparent substrate according to Example 1.

FIG. 5 is a graph showing a reflection profile of a low-transmittance transparent substrate according to Example 2.

FIG. 6 is a graph showing a transmission profile of a low-transmittance transparent substrate according to Example 2.

FIG. 7 is a graph showing a reflection profile of a low-transmittance transparent substrate according to Example 3.

FIG. 8 is a graph showing a transmission profile of a low-transmittance transparent substrate according to Example 3.

FIG. 9 is a graph showing a reflection profile of a low transmittance transparent substrate according to Example 4.

FIG. 10 is a graph showing a transmission profile of a low-transmittance transparent substrate according to Example 4.

FIG. 11 is a graph showing a reflection profile of a low transmittance transparent base material according to Comparative Example 3.

FIG. 12 is a graph showing a transmission profile of a low transmittance transparent substrate according to Comparative Example 3.

FIG. 13 is a graph showing a reflection profile of a low transmittance transparent substrate according to Comparative Example 4.

FIG. 14 is a graph showing a transmission profile of a low-transmittance transparent base material according to Comparative Example 4.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 29/88 H01J 29/88 F term (Reference) 4F100 AA02B AA12B AA20B AA21B AA37B AG00 AS00B BA02 CC00B EH46 GB41 JB07B JK01 JL09 JL10B JM01B JN01A JN01B JN02 JN06 YY00B 4G047 CA02 CA10 CC03 CD03 4G059 AA07 AC30 EA04 EA12 EA13 EA16 EB05 4J038 AA011 HA026 HA216 HA316 HA441 KA06 KA20 MA10 NA02 DA02 NA19 NA02

Claims (4)

[Claims] 1. A low transmittance transparent layer forming coating solution for forming a low transmittance transparent layer on a transparent substrate, comprising: a solvent; Black titanium compound fine particles having a diameter of 10 to 150 nm as a main component, and the mixing ratio of the carbon fine particles and the black titanium compound is set in the range of 80 to 2500 parts by weight of the black titanium compound with respect to 100 parts by weight of the carbon fine particles. A coating liquid for forming a low-transmittance transparent layer, comprising: 2. The black titanium compound is black titanium oxide or black titanium oxynitride.
The coating liquid for forming a low transmittance transparent layer according to the above. 3. The coating liquid for forming a low-transmittance transparent layer according to claim 1, further comprising an inorganic binder. 4. The coating liquid for forming a low transmittance transparent layer according to claim 1, wherein the inorganic binder contains silica sol as a main component.