JP7055294B2 - Method of forming coating member and siliceous coating layer - Google Patents

Description

Embodiments of the present invention relate to a method for forming a siliceous coating composition, a light transmitting member, and a siliceous coating layer.

Conventionally, silica fine particles are mixed and dispersed in resins such as acrylic, epoxy, urethane, phenol, and polyimide for the purpose of stress relaxation, hardness, heat resistance improvement, and thixo property imparting (reduction of viscosity during stirring). Is known as a technique for forming a material to be coated.

Japanese Unexamined Patent Publication No. 8-325460 Japanese Unexamined Patent Publication No. 2013-174262 Japanese Unexamined Patent Publication No. 2016-174052

However, in any of the above techniques, even if a siliceous coating film in which siliceous fine particles are dispersed is formed on a substrate such as a substrate, the substrate has desired properties such as insulating property and hard coat property (for example, insulating property and hard coat property (). There was a concern that scratch resistance, scratch resistance), heat resistance, and gas barrier properties could not always be imparted.
Further, when a siliceous coating film in which siliceous fine particles are dispersed is formed by using a light transmitting substrate as a substrate, the original light wavelength range of the light to be transmitted in the light transmitting substrate is used. It was not possible to secure the same transparency as the light transmitting substrate.

The present invention has been made in view of the above, and a silica-like coating film containing silica-like fine particles is formed and coated on a substrate such as a substrate such as glass or a semiconductor, a film member, or a sheet-like member such as a packaging member. It is an object of the present invention to provide a siliceous coating composition, a coating member, and a method for forming a siliceous coating layer, which can more reliably impart desired properties to a substrate when used as a member.
Further, when a light transmitting base material is used as the base material, a siliceous coating composition and a coating member capable of ensuring the same transparency as the original light transmitting base material in the light wavelength range of the transmitted target light. And it is an object of the present invention to provide a method for forming a siliceous coating layer.

The siliceous coating composition of the embodiment is a silica-like coating composition comprising a silica-like fine particles and a matrix member that holds the silica-like fine particles in a dispersed state, and is a silica-like fine particles and a silica-like coating composition. The carbon content in the above is 5 wt% or less.

FIG. 1 is a schematic configuration explanatory view of a glass member provided with a siliceous coating layer of an embodiment. FIG. 2 is a manufacturing flowchart of a glass member on which a siliceous coating layer is formed. FIG. 3 is an explanatory diagram of an example and a comparative example. FIG. 4 is a cross-sectional SEM image of the Pyrex glass substrate on which the siliceous coating layer of the example was formed. FIG. 5 is an explanatory diagram of the optical test results.

Next, a preferred embodiment will be described with reference to the drawings.
FIG. 1 is a schematic configuration explanatory view of a glass member provided with a siliceous coating layer of an embodiment.
Here, the glass member functions as a base material, more specifically, a light transmitting base material.
In FIG. 1, for ease of understanding, the thickness of each layer is different from the actual ratio.
The coating member 10 includes a glass substrate 11 as a light transmitting base material and a silica-based coating layer 13 in which silica-like fine particles 12 are uniformly dispersed.

Here, the portion other than the siliceous fine particles 12 constituting the siliceous coating layer 13 is referred to as a matrix (structural member) 14 for holding the siliceous fine particles 12 in a dispersed state.

In the above configuration, as the siliceous fine particles 12, known fumed silica, colloidal silica, molten silica, silica produced by a sintering pulverization method, vaporization combustion of metallic silicon, or the like can be used.

In this case, the conditions required for the siliceous fine particles 12 are the average particle size and the (volume) occupancy in the siliceous coating layer 13.
First, the average particle size will be described.
The average particle size of the siliceous fine particles 12 is preferably in the range of 2 nm to 200 nm when the light to be transmitted is visible light.
This is because when the average particle size of the siliceous fine particles 12 is less than 2 nm, it is difficult to produce the siliceous fine particles, and it is difficult to disperse them uniformly due to aggregation.

Further, when the average particle size of the siliceous fine particles 12 exceeds 200 nm, it becomes difficult to uniformly mix the siliceous coating material and the siliceous coating material used for forming the matrix 14 with the solvent, and the silica-like fine particles 12 are uniformly dispersed. This is because the average particle size becomes close to the wavelength of visible light, which is the light to be transmitted, and the transparency in the visible light region is lowered.

In this case, as the siliceous coating material, for example, any one of polysiloxane, polysilazane, and polysiloxazan is used. These siliceous coating materials eventually react with water and oxygen in the air to become silica (SiO ₂ ).

Further, the average particle size of the siliceous fine particles 12 is more preferably 5 nm or more and 50 nm or less. This is because the siliceous fine particles 12 are easy to produce, can be uniformly dispersed in the siliceous coating layer 13, and are transparent in the visible light region required by the visible light wavelength, that is, a particle size sufficiently smaller than 360-830 nm. This is because the sex can be sufficiently secured. Further, it is considered that a product having high reliability in properties other than transparency such as electrical insulation and mechanical strength can be obtained by reducing the particle size.

The above description is for the case where the transmitted target light is visible light. Similarly, in the siliceous coating layer 13, the average particles of the siliceous fine particles 12 according to the wavelength of the transmitted target light for which transparency is to be maintained. The diameter may be set.

Specifically, the average particle diameter of the siliceous fine particles 12 is set to be equal to or smaller than the wavelength of the transmitted light. When the average particle size of the siliceous fine particles 12 is sufficiently small with respect to the wavelength of the transmitted light, Rayleigh scattering occurs and is inversely proportional to the fourth power of the wavelength (proportional to the fourth power of the frequency). Therefore, it is preferable to set the average particle size of the siliceous fine particles 12 in consideration of this as well.

Next, the (volume) occupancy of the silica fine particles 12 in the silica coating layer 13 will be described.
The (volume) occupancy of the siliceous fine particles 12 in the siliceous coating layer 13 is preferably 3 vol% or more and 80 vol% or less.

This is because when the (volume) occupancy of the siliceous fine particles 12 in the siliceous coating layer 13 is less than 3 vol%, the thickening effect due to the stress reduction expected by the mixing of the siliceous fine particles 12 becomes small.

Further, when the (volume) occupancy of the siliceous fine particles 12 in the siliceous coating layer 13 exceeds 80 vol%, voids are likely to be formed between the silica fine particles 12, so that the insulating property and the hard coat property are deteriorated. Because it does.

Even more preferably, the volume occupancy of the siliceous fine particles 12 in the siliceous coating layer 13 is 10 vol% or more and 70 vol% or less. When it is less than 10 vol%, the stress relaxation effect is smaller than that of the silica coating layer 13 alone which does not contain the silica fine particles 12, and when it is more than 70 vol%, other than the silica fine particles of the silica coating layer 13 This is because pores are likely to occur between the components (silica produced by the silica coating material reacting with water and oxygen in the air) and the siliceous fine particles 12, and the mechanical strength and insulating properties are deteriorated. ..

Further, as a condition required for both the siliceous fine particles 12 and the siliceous coating layer 13, a carbon content can be mentioned.
The carbon content of both the siliceous fine particles 12 and the siliceous coating layer 13 is preferably 0.05 wt% or more and 5 wt% or less.

This is because if the carbon content of the siliceous fine particles 12 and the carbon content of the siliceous coating layer 13 are each less than 0.05 wt%, production becomes difficult. This is also because the dispersibility of the siliceous fine particles 12 in the siliceous coating layer 13 is also lowered.

Further, when the carbon content of the siliceous fine particles 12 and the carbon content of the siliceous coating layer 13 each exceed 5 wt%, the insulating property, the hard coat property (scratch resistance, scratch resistance), the heat resistance, and the gas barrier property are lowered. Because.

Further, the carbon content of the siliceous fine particles 12 and the carbon content of the siliceous coating layer 13 are more preferably 0.03 wt% or more and 3 wt% or less, respectively.

If it is less than 0.03 wt%, there is a concern that the manufacturing cost for removing the carbon component of the siliceous fine particles 12 and the siliceous coating layer 13 (and thus the siliceous coating material) will increase, and if it exceeds 3 wt%, electricity will be charged. This is because there is a concern that the insulation, mechanical strength, heat resistance, etc. will deteriorate.

Further, a condition required for the siliceous coating layer 13 is a film thickness.
The film thickness of the siliceous coating layer 13 is preferably 2 nm or more and 100 μm or less.
This is because if the film thickness of the siliceous coating layer 13 is less than 2 nm, it becomes difficult to control the film thickness.

When the film thickness of the siliceous coating layer 13 exceeds 100 μm, cracks are generated in the siliceous coating layer 13 due to stress, or the viscosity of the coating liquid used for forming the siliceous coating layer 13 increases to form a film. This is because the sex worsens.

Further, the film thickness of the siliceous coating layer 13 is more preferably 10 nm or more and 30 μm or less.
If it is less than 10 nm, the film thickness is smaller than the fine particle diameter, so the smoothness of the film surface is inferior. This is because it is difficult to obtain a uniform film thickness in the case of the method of forming a film.

Further, when the siliceous coating layer 13 is formed on a light transmitting substrate such as a glass substrate and compared with the haze rate (diffusion transmittance / total light transmittance) of only the light transmitting substrate, the silica coating layer 13 is obtained. The rate of increase in the haze rate after formation is said to be 1% or less.

This is a state in which the dispersibility of the siliceous fine particles 12 in the siliceous coating layer 13 is lowered when the rate of increase in the haze rate after the formation of the siliceous coating layer 13 exceeds 1%, and only the transparency is achieved. This is because the insulating property, flatness, gap fill property, and gas barrier property are deteriorated, which is not preferable.

Further, the rate of increase in the haze rate of the light transmitting substrate on which the siliceous coating layer 13 is formed is more preferably 0.7% or less as compared with the haze rate of only the light transmitting substrate.
When the increase rate of the haze rate is 0.7% or less, the dispersibility of the siliceous fine particles 12 in the siliceous coating layer 13 is sufficient, which is desirable in applications requiring high transparency such as a display film. This is because it can demonstrate its performance.

In the above description, a light-transmitting base material has been described as an example of the base material, but opaque substrates, sheet-like members, and the like can also be embedded, flat, insulating, gap-filled, and gas (oxygen, water vapor, etc.). ) It can be applied to other base materials that require barrier properties, etc. in the same manner.

Next, a method of manufacturing a coating member in which a siliceous coating layer is formed on a glass substrate will be described. Here, the glass substrate functions as a light transmitting base material (base material).
FIG. 2 is a flow chart for manufacturing a coating member in which a siliceous coating layer is formed on a glass substrate.
First, the siliceous fine particles 12 having a predetermined average particle size (2 nm to 200 nm) and having a predetermined carbon content (0.05 wt% or more and 5 wt% or less) are weighed in a predetermined amount (step S11).

In this case, it is preferable to apply a surface treatment to the siliceous fine particles 12 to improve the dispersibility. As the surface treatment, it is desirable to apply a surface treatment agent so that an alkyl group such as a methyl group or an ethyl group, an aromatic group such as a phenyl group, an organic group such as a vinyl group, a methacrylic group or an organosilyl group is located on the surface. Is done. Since all the corresponding surface treatment agents contain organic groups, the carbon content of the treated siliceous fine particles 12 is set to be 0.05 wt% or more and 5 wt% or less.

In parallel with this, a predetermined amount of a predetermined siliceous coating material of any one of polysiloxane, polysilazane, and polysiloxazan having a carbon content of 0.1 wt% or more and 8 wt% or less is weighed (step). S12).

Subsequently, the weighed siliceous fine particles 12 are mixed with a single or a plurality of kinds of solvents selected from predetermined solvents to prepare a siliceous fine particle liquid. In parallel with this, the siliceous coating material is mixed with a single solvent or a plurality of kinds of solvents selected from predetermined solvents to prepare a siliceous coating material liquid. Further, the siliceous fine particle liquid and the siliceous coating material liquid are mixed to prepare a siliceous fine particle mixed liquid (step S13).

Here, as the predetermined solvent corresponding to the siliceous fine particles 12 and the siliceous coating material, aromatic hydrocarbons such as toluene, xylene and trimethylbenzene, saturated hydrocarbons such as hexane, hexene and octane, butyl ether and amyl Examples thereof include ethers such as ether and anisole, esters such as ethyl acetate, propyl acetate and butyl acetate, and ketones such as diethyl ketone, methyl isobutyl ketone and cyclohexanone.

Then, the prepared siliceous fine particle mixed solution is set in a distillation apparatus under predetermined conditions, the solvent is evaporated until the total amount reaches a predetermined amount, and the solvent is concentrated to obtain a concentrated silica fine particle mixed solution (step S14). That is, concentration is performed so that the concentration (solid content concentration) of the siliceous fine particles 12 in the concentrated silica fine particle mixed solution becomes a predetermined value, and a concentrated silica fine particle mixed solution is obtained.

Subsequently, the siliceous fine particle mixture having a predetermined solid content concentration is cooled to room temperature (step S15).

A predetermined organic solvent is added to the siliceous fine particle mixed solution cooled to room temperature to obtain a predetermined amount of silica fine particle concentrate at a predetermined concentration (step S16).
Next, the silica fine particle concentrate is filtered with a filter (step S17).
As a result, the average particle size of the siliceous fine particles 12 contained in the silica fine particle concentrate can be surely set within a desired range.

Subsequently, the step of applying the filtered silica fine particle concentrate to the glass substrate (light transmitting substrate) 11 and drying it is repeated once or a plurality of times (step S18).

The dried glass substrate 11 is heated at a predetermined temperature for a predetermined time at a heating temperature (for example, 300 degrees) of 50 degrees Celsius or higher (hereinafter, the notation of degrees Celsius is omitted) corresponding to the type of solvent in the heating device. After heating, the mixture is slowly cooled in the heating device until it reaches room temperature to form a coating member 10 having a siliceous coating layer 13 formed on the glass substrate 11 (step S19). By this heat treatment, almost all of the solvent is evaporated.

In the above manufacturing method, since the matrix 14 constituting the siliceous coating layer 13 is produced by curing a plurality of types of siliceous coating materials, the carbon content (carbon component) contained in these silica coating materials is contained. ) Is high, the carbon content of the matrix after curing increases, and the insulating property, hard coat property (scratch resistance, scratch resistance), heat resistance, and gas barrier property deteriorate, which is not preferable. Therefore, the preferable range of carbon content in the siliceous coating material for forming the matrix 14 is 0.1 wt% or more and 8 wt% or less.

This is because when the carbon content in the siliceous coating material for forming the matrix 14 is less than 0.1 wt%, it is difficult to manufacture the raw material such as purification, and further, the manufacturing cost increases.

Further, when the carbon content in the siliceous coating material for forming the matrix 14 exceeds 8 wt%, the carbon content in the formed siliceous coating layer 13 is likely to exceed 5 wt%, ensuring the desired performance. This is because there is a possibility that it cannot be done.

Further, the carbon content in the siliceous coating material for forming the matrix 14 is more preferably 0.05 wt% or more and 5 wt% or less.
If it is less than 0.05 wt%, it is not easy to purify the raw material and there is a concern that the manufacturing cost will increase. If it exceeds 5 wt%, as described above, the electrical insulation and mechanical properties of the finally obtained silica film This is because there is a concern that the strength and heat resistance will decrease.

As described above, according to the coating member 10 of the present embodiment, desired characteristics are imparted to the glass substrate which is a light transmitting base material, for example, insulation characteristics, flattening characteristics, gap fill characteristics (unevenness of the substrate). (Filling characteristics), heat resistance imparting characteristics, gas barrier characteristics (oxygen, water vapor permeation suppression) and stain prevention characteristics can be imparted, and transparency equivalent to that of the original light transmissive substrate is ensured (equal haze rate is ensured). )can do.

In the above description, the case where the siliceous coating layer 13 is used as the hard coat layer (film) on the glass substrate 11 has been described, but the insulating film, the flattening film, the gap fill film (the film that fills the unevenness of the substrate), and the like. It is also possible to use a siliceous coating layer as a heat resistant film, a gas barrier film (oxygen, water vapor permeation suppression), and a stain prevention film.

Although the embodiment of the present invention has been described above, this embodiment is an example and is not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

Next, examples of the present invention will be specifically described.
FIG. 3 is an explanatory diagram of an example and a comparative example.

[1] Example First, a method of forming the coating member of the embodiment will be described. In the following description, for ease of understanding, the step numbers in FIG. 2 described above are described.
In this example, as shown in FIG. 3, fumed silica having an average particle diameter of 20 nm and a carbon content of 3 wt% was weighed and prepared as the siliceous fine particles 12 (step S11).

Subsequently, fumed silica, which is the prepared siliceous fine particles 12, is dispersed in a methyl isobutyl ketone solution so as to have a content of 20 wt% to prepare 100 g of a methyl isobutyl ketone dispersion.
In parallel with this, 1 wt% polysilazane hydride (silica coating material) is weighed (step S12) and dissolved in a xylene solution to prepare 100 g of a xylene solution containing 20 wt%.

Subsequently, while stirring the xylene solution of hydrogenated polysilazane (silica coating material) at room temperature, the methylisobutylketone dispersion of the siliceous fine particles 12 was applied to 100 g of the xylene solution of hydrogenated polysilazane (silica coating material) for 3 minutes. And gradually inject to prepare a 200 g silica fine particle mixed solution (step S13).
Then, the silica fine particle mixture is set in a distillation apparatus (the evaporator is at 50 degrees and 10 torr), and the solvent is evaporated until the total amount reaches 100 g (step S14).

Then, the mixture is cooled to room temperature (step S15), 20 g of xylene is added, and a silica fine particle concentrate of 120 g having a predetermined concentration is obtained (step S16).
Next, the silica fine particle concentrate is filtered through a Teflon filter having a pore size of 200 nm (step S17).

5 g of the filtered silica fine particle concentrate was dropped onto a 50 mm square, 0.7 mm thick Pyrex glass substrate (light transmitting substrate), and the spin coater was applied under coating conditions of 1,000 rpm for 50 seconds, and 30 at room temperature. It was allowed to stand for a minute to dry (step S18; first time).

Then, 5 g of the filtered silica fine particle concentrate was dropped again onto the Pyrex glass substrate coated with the dried silica fine particle concentrate, and the mixture was applied at 1,000 rpm for 50 seconds under the same conditions as the first coating. It was allowed to stand at room temperature for 30 minutes to dry (step S18; second time).

An example in which the dried Pyrex glass substrate was heated in an oven at 300 degrees for 1 hour, then left in the oven and slowly cooled to room temperature (step S19) to form a siliceous coating layer on the Pyrex glass substrate. It was used as a coating member.

[2] Comparative Example Next, a method of forming the coating member of the comparative example will be described.
In this comparative example, as shown in FIG. 3, the siliceous fine particles 12 are dissolved in ethanol water as a solvent and dispersed to prepare 5 g of an ethanol aqueous dispersion containing 20 wt% of the siliceous fine particles 12 having an average particle diameter of 20 nm. do. In parallel with this, hydrogenated polysilazane having a carbon content of 1 wt% is dissolved in xylene as a solvent to prepare 100 g of a xylene solution containing 20 wt% of hydrogenated polysilazane.

Then, 5 g of the prepared ethanol aqueous dispersion was gradually poured into 100 g of the xylene solution over 3 minutes while stirring at room temperature.

Then, the solvent is evaporated until the total amount reaches 100 g with a distillation apparatus (evaporator under 50 degrees and 10 torr), and then 100 g of xylene is injected and the total amount becomes 100 g again with a distillation apparatus (evaporator under 50 ° C and 10 torr conditions). Evaporate until it becomes.

Then, the mixture is cooled to room temperature, 20 g of xylene is added, and 120 g of a silica fine particle concentrate is obtained.
5 g of the silica fine particle concentrate is dropped onto a Pyrex glass substrate having a 50 mm square shape and a thickness of 0.7 mm, and the spin coater is applied at 1,000 rpm for 50 seconds.

Subsequently, it was allowed to stand at room temperature for 30 minutes to dry.
Then, 5 g of the filtered silica fine particle concentrate is dropped again onto the Pyrex glass substrate coated with the dried silica fine particle concentrate, and the silica fine particle concentrate is applied at 1,000 rpm for 50 seconds, which is the same condition as the first coating.

Then, it was left at room temperature for 30 minutes to dry.
After heating the dried Pyrex glass substrate in an oven at 300 degrees for 1 hour, the Pyrex glass substrate was left in an oven and slowly cooled to room temperature to form a silica-like coating layer on the Pyrex glass substrate. bottom.

[3] Test Results FIG. 4 is a cross-sectional SEM (Scanning Electron Microscope) image of a Pyrex glass substrate on which the siliceous coating layer 13 of the example was formed.

According to this cross-sectional SEM image, it can be seen that the siliceous fine particles 12 (granular substances that appear white in the cross-sectional SEM image) of about 20 nm are uniformly dispersed, and that the aggregation and vacancies of the particles cannot be confirmed.
The (volume) occupancy of the siliceous fine particles in the siliceous coating layer was about 62 vol%.
The film thickness of the thin film was 4 μm.

FIG. 5 is an explanatory diagram of the optical test results.
After the above treatment, the haze rate of the glass member after film formation measured by the spectral reflectance transmittance measuring device is 0.4%, which is 0 as compared with the Pyrex glass substrate (haze rate 0.3%) before coating. It only increased by 1% and remained transparent as a coating member.
Further, as shown in FIG. 5, the coating member of the example obtained the same values as the Pyrex glass substrate before coating in all of the total light transmittance, the parallel transmittance and the diffusion transmittance.

Further, as a result of measuring the element composition in the siliceous coating layer 13 by X-ray photoelectron spectroscopy (XPS: after sputtering treatment) using a photoelectron spectroscope (ESCA) manufactured by Nippon Denshi Co., Ltd., the carbon content (SiO ₂ ). (Converted from% of carbon atoms in the equivalent) was 3 wt%.

As a quantification method, the binding energy was calculated from the CC bond (carbon-carbon bond) peak and the CO bond (carbon-oxygen bond) peak in the 284-288 eV region.

On the other hand, in the coating member of the comparative example, white cloudiness was observed instead of transparent, and the haze rate was 10.3%, which was 10.0 compared to the Pyrex glass substrate (haze rate 0.3%) before coating. Was increasing by%.
Further, as shown in FIG. 5, it can be seen that the coating member of the comparative example has lower performance than the Pyrex glass substrate before coating in all of the total light transmittance, the parallel transmittance and the diffusion transmittance.

As described above, according to the examples, insulation characteristics, flattening characteristics, gap fill characteristics (characteristics for filling irregularities on the substrate), heat resistance imparting characteristics, gas barrier characteristics (oxygen and water vapor permeation suppression) and stain prevention characteristics Etc., and the same transparency as the original light-transmitting base material (base material: Pyrex glass substrate) can be secured (the same haze rate can be secured), as compared with the comparative example. It was found to have more suitable properties.

10 Coating member 11 Glass substrate (base material, light transmitting base material)
12 Silica fine particles 13 Silica coating layer (silica coating composition)
14 Matrix

Claims (11)

With the base material
With a siliceous coating layer laminated on the substrate,
The siliceous coating layer has a siliceous fine particles and a matrix that holds the siliceous fine particles in a dispersed state, and the carbon content in the siliceous fine particles and the siliceous coating layer is 0.05 wt% or more and 5 wt. % Or less,
The matrix is one of polysiloxane, polysilazane, and polysiloxazan.
Coating member. The carbon content in the siliceous fine particles and the siliceous coating layer is 0.1 wt% or more and 3 wt% or less.
The coating member according to claim 1. The substrate is either a substrate or a sheet-like member.
The coating member according to claim 1 or 2. The base material is a light transmitting member and is
The silica fine particles have an average particle diameter equal to or smaller than the wavelength of the light to be transmitted by the light transmitting member.
The transmitted target light is visible light.
The average particle size is 2 nm or more and 200 nm or less.
The coating member according to any one of claims 1 to 3. The rate of increase in the haze rate of the light transmitting member on which the siliceous coating layer is formed is 1% or less with respect to the haze rate of the light transmitting member alone.
The coating member according to claim 4. The rate of increase in the haze rate of the light transmitting member on which the siliceous coating layer is formed is 0.7% or less with respect to the haze rate of the light transmitting member alone.
The coating member according to claim 5. The carbon content in the siliceous coating material for forming the matrix is 0.1 wt% or more and 8 wt% or less.
The coating member according to any one of claims 1 to 6. The volume occupancy of the siliceous fine particles in the siliceous coating layer is 3 vol% or more and 80 vol% or less.
The coating member according to any one of claims 1 to 7. A method for forming a siliceous coating layer having a carbon content of 0.05 wt% or more and 5 wt% or less.
Silica fine particles having an average particle size equal to or less than the wavelength of the light to be transmitted and a carbon content of 0.05 wt% or more and 5 wt% or less, and polysiloxanes and polysilazanes having a carbon content of 0.1 wt% or more and 8 wt% or less. After dispersing or dissolving any of the siliceous coating materials of polysiloxazan in a predetermined solvent, the dispersion liquid of the siliceous fine particles and the solution of the siliceous coating material are mixed to prepare a mixed solution. The process and
The process of distilling the solid content concentration of the mixed solution to adjust it to a predetermined concentration, and
The process of applying the mixed solution after adjusting the solid content concentration to the light transmitting substrate, and
The process of drying the light-transmitting substrate coated with the mixed solution and then heating it at a temperature of 50 ° C. or higher, and
Equipped with
The silica fine particles have an average particle diameter equal to or smaller than the wavelength of the light to be transmitted by the light transmitting substrate.
The transmitted target light is visible light.
The average particle size is 2 nm or more and 200 nm or less.
A method for forming a siliceous coating layer. Solvents for dissolving the siliceous coating material include aromatic hydrocarbons such as toluene, xylene and trimethylbenzene, saturated hydrocarbons such as hexane, hexene and octane, ethers such as butyl ether, amyl ether and anisole. It is selected from one or more kinds of solvents selected from esters such as ethyl acetate, propyl acetate and butyl acetate, and ketones such as diethyl ketone, methyl isobutyl ketone and cyclohexanone.
The method for forming a siliceous coating layer according to claim 9. Solvents for dispersing the siliceous fine particles include aromatic hydrocarbons such as toluene, xylene and trimethylbenzene, saturated hydrocarbons such as hexane, hexene and octane, ethers such as butyl ether, amyl ether and anisole, and acetic acid. It is selected from one or more kinds of solvents selected from esters such as ethyl, propyl acetate and butyl acetate, and ketones such as diethyl ketone, methyl isobutyl ketone and cyclohexanone.
The method for forming a siliceous coating layer according to claim 9 or 10.

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