JP7169493B1 - Coating liquid, method for producing same, method for producing substrate with film - Google Patents

Abstract

Provided is a coating liquid capable of forming a thick film with a high refractive index on a substrate. According to the present invention, a coating liquid containing a titanium-containing oxide, an organic binder, and an adamantane derivative is used to form a film on a substrate. This coating liquid contains 50 to 75% by weight of the titanium-containing oxide in the solid content, 10 to 35% by weight of the adamantane derivative in the solid content, and 10 to 25% by weight of the organic binder in the solid content. preferably Moreover, it is preferable to use an organic binder having an alkoxy group.

Description

TECHNICAL FIELD The present invention relates to a coating liquid for forming a thick film with a high refractive index on a substrate.

BACKGROUND ART Conventionally, high refractive index films have been used for eyeglasses, lenses, touch panels, and the like. In order to form such a film, a coating liquid containing titania particles with a high refractive index is used. Further, it is known to form a crack-resistant high refractive index film using a coating liquid containing titanium alkoxide and silane alkoxide (see, for example, Patent Document 1).

It is also known to prepare a coating liquid for forming a high refractive index film using a resin having an adamantane skeleton with a high refractive index (see, for example, Patent Document 2).

JP 2016-194008 A Japanese Patent Publication No. 2019-510119

A high refractive index film can be formed on a substrate using the coating liquid of Patent Document 1. However, since the coating film tends to shrink during film formation, a thick film of 150 nm or more cannot be formed. Moreover, since it is necessary to heat the film at a high temperature (300° C. or higher) when curing the film, the base material is easily distorted.

Although the coating liquid of Patent Document 2 contains a resin with a high refractive index, the density of the formed film is low, so that only a refractive index of about 1.7 can be obtained.

An object of the present invention is to provide a coating liquid which has a high refractive index and is capable of forming a thick film.

Therefore, a coating liquid containing a titanium-containing oxide, an organic binder, and an adamantane derivative was used to form a film on a substrate. Further, the ratio of these components in the solid content is preferably 50 to 75% by weight for the titanium-containing oxide, 10 to 35% by weight for the adamantane derivative, and 10 to 25% by weight for the organic binder. Also, the organic binder preferably has an alkoxy group.

Further, the method for producing the coating liquid includes a step of preparing a dispersion of the titanium-containing oxide (preparing step), and a step of mixing the dispersion of the titanium-containing oxide and an organic binder to prepare a mixture (mixing step). , and a step of adding an adamantane derivative (adding step).

The coating liquid of the present invention contains a titanium-containing oxide (hereinafter referred to as titanium oxide), an organic binder and an adamantane derivative. When such a coating liquid is used, a film in which the adamantane derivative and the organic binder are densely packed around the titanium oxide is formed. That is, since the film becomes dense, the density of the film increases. Therefore, the refractive index and transparency of the film are increased.

Since the refractive index of titanium oxide is high, if the titanium oxide is 50% by weight or more of the solid content in the coating liquid, the refractive index of the film will be high. If the titanium oxide is 75% by weight or less of the solids contained in the coating liquid, the titanium oxide is easily dispersed in the coating liquid and the film.

If the organic binder is 25% by weight or less of the solid content in the coating liquid, the content of titanium oxide and adamantane derivative is relatively high. Titanium oxide and adamantane derivatives have a higher refractive index than the organic binder, so a high content of these will increase the refractive index of the film. On the other hand, when the organic binder accounts for 10% by weight or more of the solid content in the coating liquid, the compatibility between the titanium oxide and the adamantane derivative is enhanced. Therefore, the titanium oxide is easily dispersed in the coating liquid. Therefore, the film is easily formed in a state in which the titanium oxide is dispersed, and the titanium oxide can be uniformly present in the film. As a result, the film becomes more transparent. Also, when a film is formed in a state where titanium oxide is dispersed, voids in the film are reduced as compared with the case where titanium oxide is agglomerated, so the film becomes denser.

In particular, when the solid content of the coating liquid is 50 to 75% by weight, the adamantane derivative is 10 to 35% by weight, and the organic binder is 10 to 25% by weight, a component with a high refractive index (titanium oxide titanium oxide and adamantane derivative) are high, and titanium oxide easily disperses in the coating solution or film.

In the solid content of the coating liquid, when the content (weight) of the organic binder is 1, the content of titanium oxide is 2.5 to 4.0, and the content of adamantane derivative is 0.5 to 1.5. If it is in the range of , the film will be dense. In particular, it is preferable that the content of titanium oxide is in the range of 3.0 to 3.5, and the content of adamantane derivative is in the range of 0.8 to 1.3.

If necessary, other solid components (oxides, resins [monomers, oligomers, polymers], additives [curing agents and surface control agents]) may be added. When these are added, if the concentrations of titanium oxide, adamantane derivative and organic binder are within the above range, the film becomes dense.

When the solid content in the coating liquid is 5% by weight or more, it becomes easy to form a thick film of 150 nm or more with a uniform thickness. 10% by weight or more is more preferable. Further, when the solid content in the coating liquid is 50% by weight or less, the titanium oxide tends to disperse in the film. 45% by weight or less is more preferable.

When the organic binder has an alkoxy group, compatibility with titanium oxide is enhanced. Furthermore, the alkoxy group is hydrolyzed in the coating liquid and undergoes a dehydration condensation reaction with the OH group of the titanium oxide (hereinafter, hydrolysis and dehydration condensation are collectively referred to as coupling reaction). That is, titanium oxide chemically bonds with the organic binder. Therefore, the film becomes dense. Also, the hardness of the film increases. Since the titanium oxide chemically bonded to the organic binder has high compatibility with the adamantane derivative and the organic solvent, it is easily dispersed in the coating liquid and the film.

Also, when the alkyl group bonded to the oxygen atom of the alkoxy group is a methyl group or an ethyl group, the organic binder is easily hydrolyzed. That is, it easily undergoes a coupling reaction with titanium oxide. Further, when a catalyst that promotes hydrolysis of the alkoxy group is added to the coating liquid, the coupling reaction is facilitated.

When the organic binder has two or more alkoxy groups, the organic binder that has not undergone coupling reaction (unreacted organic binder) is polymerized in the coating solution. As a result, oligomers of the organic binder are formed. The oligomers are believed to have a polarity intermediate between titanium oxides and adamantane derivatives. When such an oligomer is contained in the coating liquid, the solid content is easily dispersed in the coating liquid, resulting in a dense film. At this time, if an organic binder having 2 to 3 alkoxy groups is used, the compatibility between the titanium oxide and the adamantane derivative is enhanced. Therefore, the solid content is easily dispersed in the film during film formation. In particular, when an organic binder having three alkoxy groups is used, the oligomer becomes moderately polar. Therefore, the compatibility between the titanium oxide and the adamantane derivative is enhanced.

At this time, when 80% or more of the unreacted organic binder forms an oligomer, the compatibility between the titanium oxide and the adamantane derivative is enhanced. When the amount of the monomer is 10% or less of the total amount of the unreacted organic binder, the organic binder is difficult to volatilize during film formation, and a dense film can be formed.

When the molecular weight of the oligomer is 5000 or less, the strength of the film and the adhesion of the film to the substrate are increased. In particular, when the molecular weight is in the range of 500 to 5000, the compatibility between the titanium oxide and the adamantane derivative is high. More preferably, the molecular weight ranges from 1,500 to 4,000.

When the organic binder having an alkoxy group further has a (meth)acrylate group, the (meth)acrylate groups are bonded to each other by ultraviolet irradiation, so that the film can be cured at a low temperature. In addition, the (meth)acrylate groups of the organic binder are bonded to the (meth)acrylate groups of other solids during curing, resulting in a dense film. Oligomers formed from organic binders with alkoxy groups have multiple (meth)acrylate groups. Upon curing, such oligomers combine with multiple solids, resulting in a denser film.

Moreover, when the organic binder is an organic silicon compound, it is easy to handle industrially. The organosilicon compound can be represented by the general formula (RO) _m Si(Y) _4-m . where R is Me or Et. m represents an integer of 1 to 4; Y is an organic compound having a (meth)acrylate group. Y specifically includes -(CH ₂ ) ₃ OC(=O)C(CH ₃ )(=CH ₂ ) or -(CH ₂ ) ₃ OC(=O)CH(=CH ₂ ).

When the adamantane derivative of the monomer is used, the adamantane derivative can be polymerized with the solid content in the coating liquid, so that a denser film can be obtained. Also, monomers are more likely to shrink than oligomers or polymers during curing. Therefore, the film becomes dense.

At this time, when the adamantane derivative has two or more (meth)acrylate groups in the molecule, it can be polymerized with other solids having two or more (meth)acrylate groups. In particular, an adamantane derivative having two (meth)acrylate groups has less steric hindrance than three or more (meth)acrylate groups. Therefore, the use of such an adamantane derivative results in a dense film. At this time, if (meth)acrylate groups are bonded to the 1st and 3rd positions of the adamantane skeleton, the steric hindrance of the adamantane derivative is further reduced. Moreover, when the adamantane derivative does not have a substituent other than a (meth)acrylate group, steric hindrance is reduced. Moreover, when the molecular weight of the adamantane derivative is 350 or less, the steric hindrance is reduced.

Instead of titanium oxide, the coating liquid may contain a precursor of titanium oxide. Examples of precursors include monomers and oligomers. Furthermore, if the precursor is titanium alkoxide, it will be hydrolyzed and condensed when the coating film is heated and dried to form titanium oxide. Since the organic binder having an alkoxy group hydrolyzes and condenses with titanium alkoxide, the film becomes dense.

When the coating liquid contains an organic solvent, the solid content tends to disperse in the coating liquid. Such a coating liquid can be easily applied to the substrate. Furthermore, when the content of the organic solvent is 50% by weight or more, the titanium oxide is easily dispersed in the coating liquid or the film. More preferably, the content is 60% by weight or more. On the other hand, when the content of the organic solvent is 95% by weight or less, it becomes easy to form a film having a thickness of 150 nm or more with a uniform thickness. 90% by weight or less is more preferable.

Moreover, when the boiling point of the organic solvent is 50° C. or higher, the coating liquid can be dried slowly. Therefore, the titanium oxide is easily dispersed uniformly in the film. On the other hand, if the boiling point of the organic solvent is 200° C. or less, the coating liquid can be dried at a low temperature of substantially 120° C. or less in a few minutes, thereby increasing productivity.

When the organic solvent has an ester bond, an ether bond, or a ketone group, the surface of the film becomes smooth so that the adamantane derivative can be dispersed in the coating liquid. If the organic solvent has two or more of these bonds or functional groups, the solid content will be more easily dispersed in the coating liquid. Two or more of the same type may be used, or one or more of each of two different types may be used. Organic solvents having three are more preferred.

Organic solvents include propylene glycol monomethyl ether (PGME) or propylene glycol monomethyl ether acetate (PGMEA). Among them, PGMEA is preferable.

A curing agent, a surface control agent, and the like are added to the coating liquid as necessary. If the curing agent is a photopolymerization initiator, the film can be formed at a low temperature. Among them, when an acylphosphine oxide-based photopolymerization initiator is used, curing of the film proceeds efficiently and the film becomes dense. When the content of the photopolymerization initiator is 2 parts by mass or more with respect to 100 parts by mass of the adamantane derivative, the curing reaction proceeds easily and the hardness of the film increases. On the other hand, when the content is 10 parts by mass or less, the ratio of excess polymerization initiator decreases, so polymerization proceeds efficiently.

If the coating liquid does not contain solids other than titanium oxide, organic binder, adamantane derivative, and curing agent, the film tends to be dense. At this time, these may include those that have changed over time.

Titanium oxide will be described in detail below.

The crystal structure of titanium oxide may be anatase, rutile, brookite, or amorphous. A plurality of crystals may be mixed. A portion of the titanium oxide may be amorphous. When the titanium oxide contains 80% by weight or more of titanium oxide in terms of TiO ₂ concentration, the refractive index of the film increases. 90% by weight or more is more preferable, and 95% by weight or more is even more preferable.

If the titanium oxide is particulate (hereinafter particulate titanium oxide is simply referred to as particles), the film tends to be dense. Moreover, it is easy to form a thick film.

The larger the crystallite size of the particles, the higher the density of the particles and the higher the refractive index of the film. The crystallite diameter is preferably 1 nm or more, more preferably 5 nm or more. On the other hand, when the crystallite diameter is 100 nm or less, the haze of the film becomes low. 50 nm or less is more preferable. In addition, when the particle diameter of the particles is 100 nm or less, the haze of the film becomes low.

If the particles contain an inorganic component other than titanium oxide, they will be easily dispersed in the coating liquid. Among them, when inorganic components such as alumina, silica, zirconia, and tin oxide are contained in the particles in an amount of 0.5 to 10.0% by weight in terms of Al ₂ O ₃ , SiO ₂ , ZrO ₂ , and SnO ₂ , respectively, the particles are added to the coating liquid. easily dispersed. A range of 0.5 to 6.0% by weight is more preferred. In particular, titanium oxide containing 1 to 3% by weight of tin oxide in terms of SnO ₂ tends to form particles. In particular, particles containing 0.5 to 1.5% by weight of alumina in terms of Al ₂ O ₃ easily disperse in the solvent.

Further, when the particles are treated with 1 to 30 parts by mass of the surface treatment agent per 100 parts by mass of the particles, the particles are easily dispersed in the organic solvent. More preferably, the particles are treated with 5 to 22 parts by mass of the surface treatment agent.

In addition, since the surface treatment agent having an alkoxy group easily undergoes a coupling reaction with the particle surface, the particles are easily dispersed in the organic solvent. The more alkoxy groups, the more likely the coupling reaction will occur on the particle surface. A surface treatment agent having 3 to 4 alkoxy groups is preferred, and a surface treatment agent having 4 alkoxy groups is more preferred.

Also, if the alkoxy group is a methoxy group or an ethoxy group, it is easily hydrolyzed. That is, the smaller the molecular weight of the alkyl group in the alkoxy group, the easier the hydrolysis of the alkoxy group.

Examples of surface treatment agents include silicon compounds, titanium compounds, zirconium compounds, and aluminum compounds. The surface treatment agent can be represented by the general formula (RO) _n M(X) _4-n . n is an integer of 1-4. M represents either Si, Ti, Zr or Al. X as Me, Et, Pr, -(CH ₂ ) ₃ OC(=O)C(CH ₃ )(=CH ₂ ), -(CH ₂ ) ₃ OC(=O)CH(=CH ₂ ), - CH= _CH2 can be mentioned. R is Me or Et. In particular, when the surface treatment agent is a silicon compound, it is industrially easy to handle.

Next, a method for producing the coating liquid will be described. First, a dispersion of titanium oxide is prepared (preparation step). Next, a dispersion of titanium oxide and an organic binder are mixed to prepare a mixture (mixing step). An organic binder may be mixed in the preparation step. Next, a coating liquid is obtained by adding an adamantane derivative to the mixture (adding step).

Each step will be described in detail below.

<Preparation process>
First, a dispersion of titanium oxide is prepared. Here, a dispersion of titanium-containing oxide particles (hereinafter referred to as titanium oxide particles) was prepared. First, a compound containing titanium is neutralized in an aqueous solution to prepare a slurry. The prepared slurry can be washed with water to remove excess salt. Next, a hydrogen peroxide solution is added to the slurry to prepare an aqueous peroxotitanic acid solution. After that, it is preferable to carry out a dealkalization treatment. By heating this peroxotitanic acid aqueous solution, a dispersion of titanium oxide particles having a crystallite size of several nanometers to several tens of nanometers can be obtained. Grain growth can be controlled by adding an inorganic component other than titanium oxide before heating. In addition, the particles are easily dispersed in the coating liquid. The amount of the inorganic component to be added is preferably an amount corresponding to the concentration of the inorganic component in the particles described above. By reducing the amount added, the proportion of titanium oxide in the particles can be increased. The prepared dispersion of titanium oxide may further contain an oxide other than titanium oxide.

The surface of the particles can be treated by adding the surface treating agent to the dispersion of the particles. The surface-treated particles are easier to disperse in organic solvents. By maintaining the dispersion after the addition of the surface treatment agent at 40° C. or higher for 1 hour or more, the surface treatment agent can be treated quickly. If the time to hold at 40° C. or higher is 20 hours or less, the cost will be low. The treatment amount of the surface treatment agent is 20 to 85 parts by mass with respect to 100 parts by mass of the particles (3 to 30 parts by mass in terms of oxide {in terms of _SiO2 if the surface treatment agent is a silicon compound}). is easily dispersed in organic solvents. When a surface treatment agent is added to an aqueous dispersion of particles, aggregation of the surface treatment agent is suppressed by adding an organic solvent. Therefore, the surfaces of the particles are easily uniformly treated with the surface treatment agent. At this time, if the organic solvent to be added is alcohol, aggregation of the surface treatment agent is further suppressed. Also, alcohol is easily mixed with water.

If the solvent of the dispersion is an organic solvent, aggregation of the organic binder to be mixed later is suppressed. When the solvent of the titanium oxide dispersion is water, it is preferable to replace the water with an organic solvent. At this time, when the organic solvent is alcohol, it is easily mixed with water, so that the solvent is easily replaced. As a replacement method, a method of removing water (dehydrating) after adding an organic solvent can be mentioned. Methods of dehydration include methods such as ultrafiltration and distillation. When the titanium oxide is particles, the solvent is easily replaced if the particles are treated with a surface treatment agent.

A dispersion liquid of the precursor of titanium oxide may be prepared and used for preparing the coating liquid.

<Mixing process>
In this step, a dispersion of titanium oxide and an organic binder are mixed to prepare a mixture. At this time, by using an organic binder having an alkoxy group, the organic binder can undergo a coupling reaction with titanium oxide. The compatibility between the titanium oxide that has undergone the coupling reaction and the organic solvent is high. Unreacted organic binders are hydrolyzed and condensed to form oligomers. When the oligomer is contained in the coating liquid, the compatibility between the titanium oxide and the organic solvent is further enhanced.

When using an organic binder having an alkoxy group, the hydrolysis reaction proceeds by maintaining the temperature of the mixture at 40° C. or higher. The holding temperature is preferably 45°C or higher. Furthermore, holding for 1 hour or more facilitates the progress of the reaction. The retention time is preferably 10 hours or longer, more preferably 15 hours or longer. Further, stirring the mixture facilitates uniform condensation reaction of the organic binder with the surface of the titanium oxide. When the solvent is alcohol, if the mixture is kept at 60° C. or less, the solvent is difficult to evaporate.

Further, when the organic binder has an alkoxy group, adding a catalyst, water, or the like to the mixture promotes the hydrolysis reaction of the organic binder. If the catalyst does not easily remain in the film after film formation, the density of the film increases. Also, the hydrolysis reaction is preferably carried out on the alkali side rather than the acid side. Ammonia is suitable as a catalyst that hardly remains and can promote the hydrolysis reaction on the alkaline side.

When the amount of the organic binder mixed with 100 parts by mass of titanium oxide is 10 parts by mass or more, the titanium oxide is easily dispersed in the organic solvent. 20 parts by mass or more is more preferable, and 30 parts by mass or more is even more preferable. On the other hand, if the amount of organic binder mixed with 100 parts by mass of titanium oxide is 50 parts by mass or less, the proportion of titanium oxide in the film increases. 40 parts by mass or less is more preferable. However, when the titanium oxide is particles, 100 parts by mass is the amount including the surface treatment agent.

By replacing the solvent in the mixture with an organic solvent having an ester bond, an ether bond, or a ketone group, the adamantane derivative can be dispersed in the organic solvent. In addition, in the process of applying the coating liquid and then drying it, the stability of the film formation is enhanced, so that a uniform, dense and smooth surface film can be easily obtained. PGMEA is suitable as such an organic solvent.

<Addition process>
A coating liquid is obtained by adding an adamantane derivative to the mixture. After the addition, it is preferable to sufficiently stir using an ultrasonic device or the like. Moreover, it is preferable to add a photopolymerization initiator after the addition. Moreover, in this step, a resin other than the adamantane derivative may be further added. At this time, the order of addition does not matter.

When 10 to 40 parts by mass of an organic binder is mixed with 100 parts by mass of titanium oxide and 15 to 80 parts by mass of an adamantane derivative is added, the density of the film increases. It is more preferable to mix 20 to 40 parts by mass of the organic binder and add 20 to 50 parts by mass of the adamantane derivative. However, when the titanium oxide is particulate, 100 parts by mass is the amount including the surface treatment agent.

A film-coated substrate can be produced by applying the coating liquid described above onto a substrate.

Specifically, the film-coated substrate is obtained by applying the coating liquid onto the substrate and then drying and curing the coating liquid. Examples of coating methods include spin coating, bar coating, gravure coating, and slit coating. Here, drying means volatilizing and removing the solvent. If the drying temperature is 60°C or higher, the drying time will be shortened. Also, the solvent hardly remains in the film. Therefore, a dense film can be obtained. On the other hand, if the drying temperature is 120° C. or less, the base material is difficult to deform. Moreover, it is industrially easy to handle. The drying temperature is more preferably 100° C. or lower, more preferably 80° C. or lower. If the coating film is dried and then cured, production efficiency increases.

Examples of the present invention will be specifically described below.

[Example 1]
≪Preparation process≫
First, a dispersion of titanium oxide particles was prepared as follows. 900 g of an aqueous titanium tetrachloride solution containing 2% by weight of titanium tetrachloride in terms of TiO ₂ and 352 g of 15% by weight ammonia water were mixed to prepare a white slurry having a pH of 8.6. After filtering this slurry, it was washed with pure water to obtain 360 g of a cake having a solid concentration of 5% by weight. To 360 g of this cake, 411.2 g of 35% by weight hydrogen peroxide solution and 128.8 g of pure water were added to obtain slurry again. By heating this slurry at 80° C. for 1 hour, 900 g of an aqueous peroxytitanic acid solution containing 2% by weight of peroxytitanic acid in terms of TiO ₂ was obtained. The color of this aqueous solution was a transparent yellow-brown color. The pH of this aqueous solution was 8.1.

To 900 g of this aqueous solution, 19.4 g of silica sol containing 15% by weight of silica particles having an average particle size of 7 nm (manufactured by Nikki Shokubai Kasei Co., Ltd.: Cataloid (registered trademark) SN-350) and 1178 g of pure water were added. After that, the aqueous solution was held at 165° C. for 18 hours using an autoclave. After the aqueous solution was cooled to room temperature, it was concentrated using an ultrafiltration membrane apparatus to obtain 209.1 g of an aqueous dispersion of titanium oxide having a solid content of 10% by weight. Table 1 shows the composition of the prepared titanium oxide (ratio of inorganic components added).

While stirring 263 g of an aqueous zirconium oxychloride solution containing 2% by weight of zirconium oxychloride in terms of ZrO ₂ , 15% by weight of aqueous ammonia was added thereto to obtain a slurry of pH 8.5. This slurry was filtered and washed with pure water to obtain 52.6 g of a cake containing ₁₀ % by weight of the zirconium compound in terms of ZrO2. To 20 g of this cake were added 180 g of pure water and 12 g of a 10% by weight potassium hydroxide aqueous solution. Furthermore, after adding 40 g of 35% by weight hydrogen peroxide water, the cake was heated to 50° C. to dissolve the cake and obtain a dispersion liquid. 148 g of pure water was added to this dispersion to obtain 400 g of an aqueous zirconate peroxide solution containing 0.5% by weight of zirconate peroxide as ZrO ₂ .

Alkaline components were removed by adding a cation exchange resin (Mitsubishi Chemical Co., Ltd.) to water glass containing 2% by weight of sodium silicate in terms of SiO ₂ concentration. After that, the ion exchange resin was separated to obtain a silicic acid aqueous solution of 2% by weight as SiO ₂ .

After adding 640 g of pure water to 160 g of an aqueous dispersion of titanium oxide, the aqueous dispersion was heated to 90°C. This aqueous dispersion, 53.4 g of an aqueous zirconic acid peroxide solution, and 42.4 g of an aqueous silicic acid solution were mixed to obtain a mixture. This mixed solution was stirred at 90° C. for 1 hour and then kept at 165° C. for 18 hours using an autoclave. After the mixed solution was cooled to room temperature, it was concentrated using an ultrafiltration membrane apparatus to obtain 195.2 g of an aqueous dispersion of titanium oxide having a solid content of 10% by weight. A cation exchange resin was added (dealkalized) to 195.2 g of this aqueous dispersion. The ion exchange resin was then separated. After adding 210.1 g of a methanol solution containing 14.9 g of tetraethoxysilane (manufactured by Tama Kagaku Co., Ltd.) having an SiO ₂ equivalent concentration of 28.8% by weight dissolved therein, the mixture was stirred at 50° C. for 1 hour. After cooling this dispersion to room temperature, the solvent was replaced with methanol using an ultrafiltration membrane. Thereafter, by concentrating the dispersion, 119.2 g of a methanol dispersion of titanium oxide having a solid content concentration of 20% by weight and having a silica layer was obtained. This methanol dispersion was used as a titanium oxide dispersion.

≪Mixing process≫
Next, the titanium oxide dispersion and the organic binder were mixed. Specifically, a mixture is prepared by mixing 100 g of a methanol dispersion of titanium oxide and 3.68 g of 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-503) as an organic binder. did. The mixture was stirred at 50° C. for 19 hours. After cooling the mixture to room temperature, the solvent in the mixture was replaced with PGMEA using a rotary evaporator to obtain 103.7 g of a mixture having a solid concentration of 20% by weight.

≪Addition process≫
Next, an adamantane derivative was added to prepare a coating liquid. Specifically, 100.0 g of PGMEA in 100.0 g of a mixture having a solid concentration of 20% by weight, 6.0 g of an adamantane derivative (manufactured by Mitsubishi Gas Chemical Co., Ltd.: Diapurest (registered trademark) ADDA), and diphenyl ( A coating liquid was prepared by adding and stirring 0.36 g of 2,4,6-trimethylbenzoyl)-phenylphosphine oxide (manufactured by IGM Resins B.V.: OMNIRAD (registered trademark) TPO-H).

Table 1 summarizes the preparation conditions of the coating liquid. Using the obtained coating liquid, a substrate with a transparent film (glass substrate) was formed as follows, and the total light transmittance and haze of the substrate with the film were measured. Further, using the obtained coating liquid, a transparent film-coated substrate (silicon wafer) was formed as follows, and the refractive index and film thickness of the film-coated substrate were evaluated. Table 2 shows the measurement results and evaluation results. For Examples and Comparative Example 2, which will be described later, transparent film-attached substrates were produced in the same manner, and measured and evaluated.

≪Manufacturing of base material with transparent film (glass base material)≫
The coating liquid was applied to a glass substrate (made by Hamashin Co., Ltd.: FL glass, thickness: 3 mm, refractive index: 1.51) by a spin coating method. After drying this coating solution at 80° C. for 2 minutes, a high-pressure mercury lamp (manufactured by GS Yuasa: EYEUVMETER) was used to irradiate this coating solution with ultraviolet light under the conditions of 3000 mJ/cm ² to form a transparent film. A substrate (glass substrate) was prepared. Using a haze meter (manufactured by Nippon Denshoku Co., Ltd.: NDH-5000), the total light transmittance and haze of the substrate with a transparent coating (glass substrate) were measured. The uncoated glass substrate had a total light transmittance of 99.0% and a haze of 0.1%.

≪Manufacturing of substrate with transparent film (silicon wafer)≫
The coating liquid was applied to a silicon wafer (manufactured by Matsuzaki Manufacturing Co., Ltd.: 6-inch dummy wafer (P type), thickness: 625 μm) by spin coating. After drying this coating liquid at 80° C. for 2 minutes, this coating liquid was irradiated with ultraviolet light under the condition of 3000 mJ/cm ² using an EYEUVMETER to prepare a base material (silicon wafer) with a transparent film. Using spectroscopic ellipsometry (manufactured by Japan Semilab Co., Ltd.: SE-2000), the refractive index and film thickness of the transparent film-attached substrate (silicon wafer) were evaluated.

[Example 2]
A white slurry having a pH of 9.2 was prepared by mixing 2000 g of an aqueous titanium tetrachloride solution containing 7.5% by weight of titanium tetrachloride in terms of TiO ₂ and 2000 g of 7.5% by weight of aqueous ammonia. This slurry was filtered and washed with pure water to obtain 1500 g of a cake having a solid content of 10% by weight. 1500 g of this cake was diluted with pure water to 1.5% by weight. After adding 1714 g of 35% by weight hydrogen peroxide water to this cake, it was held at 80° C. for 1 hour to obtain 11714 g of an aqueous peroxide titanate solution containing 1.5% by weight of titanic acid in terms of TiO ₂ . rice field. After adding 3286 g of pure water to this aqueous solution, the aqueous solution was stirred to obtain a transparent yellow-brown aqueous peroxide titanic acid solution. The pH of this aqueous solution was 7.8. A cation exchange resin was added (dealkalization) to 15000 g of this aqueous titanate peroxide solution. After adding 309 g of a 1% by weight potassium stannate aqueous solution to this aqueous solution, the ion exchange resin was separated. Further, 155 g of a 1% by weight sodium aluminate aqueous solution was added and stirred. After that, this aqueous solution was held at 165° C. for 18 hours using an autoclave. After cooling this aqueous solution to room temperature, it was concentrated using an ultrafiltration membrane apparatus to obtain 3866 g of an aqueous dispersion of titanium having a solid content of 4% by weight.

To 3866 g of this aqueous dispersion were added 3866 g of methanol and 118.4 g of orthoethyl silicate (manufactured by Tama Kagaku Kogyo Co., Ltd.) of 28.8% by weight in terms of _SiO2 . After that, the mixture was stirred at 50° C. for 18 hours to obtain a water/methanol dispersion of titanium oxide.

After cooling this dispersion to room temperature, the solvent of this dispersion was replaced with methanol using an ultrafiltration membrane. By concentrating this dispersion, 943.7 g of a methanol dispersion of titanium oxide having a solid concentration of 20% by weight was obtained.

17.7 g of 5% by weight aqueous ammonia was added to 890 g of this methanol dispersion. An additional 53.3 g of KBM-503 was added and the dispersion was stirred at 50° C. for 18 hours. After cooling this dispersion to room temperature, the solvent of this dispersion was replaced with PGMEA using a rotary evaporator to obtain 943.3 g of a mixture having a solid concentration of 20% by weight.

A coating solution was prepared in the same manner as in Example 1, except that the mixture prepared in this example was used in the addition step and Diapurest ADTM manufactured by Mitsubishi Gas Chemical Company, Inc. was used as the adamantane derivative.

[Example 3]
A coating solution was prepared in the same manner as in Example 2, except that DIAPUREST HADDM manufactured by Mitsubishi Gas Chemical Company, Inc. was used as the adamantane derivative in the addition step.

[Example 4]
A white slurry having a pH of 8.6 was prepared by mixing 4500 g of an aqueous titanium tetrachloride solution containing 2% by weight of titanium tetrachloride in terms of TiO ₂ and 450 g of 15% by weight of ammonia water. This slurry was filtered and washed with pure water to obtain 900 g of a cake having a solid content of 10% by weight. After 900 g of this cake was diluted with pure water to 1.5% by weight and slurried, 1029 g of 35% by weight hydrogen peroxide solution was added to the slurry. By holding this slurry at 80° C. for 1 hour, 7039 g of an aqueous peroxytitanic acid solution containing 1.5% by weight of peroxytitanic acid in terms of TiO ₂ was obtained. After adding 1961 g of pure water to this aqueous solution, the aqueous solution was stirred to obtain a transparent yellow-brown aqueous solution of titanic acid peroxide. The pH of this aqueous solution was 8.1.

A cation exchange resin was added (dealkalization) to 9000 g of this aqueous solution. After separating the ion exchange resin, 91 g of 1% by weight sodium aluminate aqueous solution was added to the aqueous solution and the aqueous solution was stirred. This aqueous solution was held at 155° C. for 18 hours using an autoclave. After cooling this aqueous solution to room temperature, it was concentrated using an ultrafiltration membrane apparatus to obtain 2275 g of an aqueous dispersion of titanium oxide having a solid concentration of 4% by weight.

To 2275 g of this aqueous dispersion were added 2275 g of methanol and 70 g of normal ethyl silicate of 28.8% by weight in terms of SiO ₂ . Thereafter, this aqueous dispersion was stirred at 50° C. for 18 hours to obtain a water/methanol dispersion of titanium oxide. This dispersion was cooled to room temperature, and the solvent of this dispersion was replaced with methanol using an ultrafiltration membrane. By concentrating this dispersion, 555.8 g of a methanol dispersion of titanium oxide having a solid concentration of 20% by weight was obtained.

10 g of 5% aqueous ammonia was added to 500 g of this methanol dispersion. Additionally, 30 g of KBM-503 was added. The dispersion was stirred at 50° C. for 18 hours and cooled to room temperature. Thereafter, the solvent of this dispersion was replaced with PGMEA using a rotary evaporator to obtain 530 g of a mixture having a solid concentration of 20% by weight.

Coated in the same manner as in Example 1 except that the mixture prepared in this example was used in the addition step, and the amount of the adamantane derivative added was changed to 4.0 g and the amount of the photopolymerization initiator added was changed to 0.24 g. A liquid was prepared.

[Example 5]
A coating solution was prepared in the same manner as in Example 4, except that in the adding step, the amount of the adamantane derivative added was changed to 14.0 g and the amount of the photopolymerization initiator added was changed to 0.84 g.

[Example 6]
To 500 g of the methanol dispersion of titanium oxide of Example 2, 10.0 g of 5% aqueous ammonia was added. After adding 29.9 g of 3-phenyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-103), the dispersion was stirred at 50° C. for 18 hours. After cooling this dispersion to room temperature, the solvent of this dispersion was replaced with PGMEA using a rotary evaporator to obtain 529.9 g of a mixture having a solid concentration of 20% by weight.

A coating liquid was prepared in the same manner as in Example 1, except that the mixture prepared in this example was used in the addition step.

[Example 7]
An aqueous dispersion of titanium oxide was obtained in the same manner as in Example 2, except that the potassium stannate aqueous solution was not added and the addition amount of the 1% by weight sodium aluminate aqueous solution was changed to 152 g. However, the amount of the aqueous dispersion of titanium oxide after ultrafiltration was 3788 g.

In the preparation step, in the same manner as in Example 2, except that 3788 g of methanol and 116 g of normal ethyl silicate (28.8% by weight in terms of SiO ₂ ) were added to 3788 g of the titanium oxide aqueous dispersion of this example. 924.6 g of a methanol dispersion of titanium oxide having a solid concentration of 20% by weight was obtained.

In the mixing step, the solid content concentration was 20% by weight in the same manner as in Example 2, except that 17 g of 5% aqueous ammonia was added to 824 g of the methanol dispersion of titanium oxide of this example, and then 49 g of KBM-503 was mixed. 873 g of a mixture of

In the addition step, except that 100.0 g of the mixture of this example with a solid content concentration of 20% by weight was used, the amount of the adamantane derivative mixed was 8.0 g, and the amount of the photopolymerization initiator added was 0.48 g. A coating solution was prepared in the same manner as in Example 1.

[Example 8]
Example except that the mixture of Example 4 with a solid content concentration of 20% by weight was used in the addition step, and that the polymerization initiator was changed to 1-hydroxycyclohexylphenyl ketone (manufactured by IGM Resins B.V.: OMNIRAD184). A coating liquid was prepared in the same manner as in 1.

[Example 9]
A coating solution was prepared in the same manner as in Example 4, except that in the addition step, the amount of the adamantane derivative mixed was changed to 8.0 g, and the amount of the photopolymerization initiator added was changed to 0.48 g.

[Example 10]
A coating solution was prepared in the same manner as in Example 1, except that the mixture of Example 2 with a solid content concentration of 20% by weight was used in the addition step.

[Comparative Example 1]
403.71 g of methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-13) having an SiO ₂ equivalent concentration of 44.1% by weight and a solvent (manufactured by Nippon Alcohol Sales Co., Ltd.: Solmix (registered trademark) AP-11) 1061. 55 g were mixed to prepare a mixed liquid. The mixture was stirred for 30 minutes. 322.92 g of 0.1% by weight nitric acid was added to this mixed solution over 30 minutes while stirring. It was then stirred for an additional 30 minutes. The pH of the mixed solution at this time was 2.0. Furthermore, 2.86 g of triethanolamine (manufactured by Hayashi Junyaku Kogyo Co., Ltd.) was added to this mixture while stirring. Further, this mixed solution was stirred for 10 minutes to prepare a hydrolyzed compound having a concentration of 10.0% by weight in terms of SiO ₂ . The pH of the mixed solution at this time was 7.0. This hydrolyzed compound was added to 1194.03 g of stirred hexylene glycol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to obtain a dispersion of the hydrolyzed compound. This dispersion was further stirred for 30 minutes to prepare a hydrolyzed compound dispersion having a concentration of 6.0% by weight in terms of SiO ₂ .

5211.44 g of hexylene glycol (manufactured by Fujifilm Wako Pure Chemical Co., Ltd.), _261.19 g of acetylacetone (manufactured by Fujifilm Wako Pure Chemical Co., Ltd.), and 28 wt% titanium alkoxide (manufactured by Matsumoto Fine Chemical Co., Ltd.: Olga 1492.54 g of Tix (registered trademark) TA-10) was mixed to obtain a mixed liquid. The mixture was then stirred for 5 minutes. While this mixed solution was being stirred, a hydrolyzed compound dispersion having a concentration of 6.0% by weight in terms of SiO ₂ was further mixed with this mixed solution. After stirring this mixed liquid for 10 minutes, 49.75 g of pure water was added to this mixed liquid. The mixture was stirred at 25° C. for 30 minutes and then filtered through a 0.2 μm filter to prepare a coating liquid having a solid content of 6.0% by weight.

Using the obtained coating liquid, a substrate with a transparent film (glass substrate) was formed as follows, and the total light transmittance and haze were measured. Also, a base material (silicon wafer) with a transparent film was formed in the same manner, and the refractive index and film thickness were evaluated. Table 2 shows the measurement results and evaluation results.

≪Manufacturing of base material with transparent film (glass base material)≫
This coating liquid was applied onto a glass substrate by a flexographic printing method. After that, this coating liquid was dried at 90° C. for 5 minutes. After irradiating this coating liquid with ultraviolet rays (wavelength: 365 nm) at 3000 mJ/cm ² , this coating liquid was heated at 230° C. for 30 minutes to prepare a substrate with a transparent film (glass substrate). Using NDH-5000, the total light transmittance and haze of the transparent film-coated substrate (glass substrate) were measured. The uncoated glass substrate had a total light transmittance of 99.0% and a haze of 0.1%.

≪Manufacturing of substrate with transparent film (silicon wafer)≫
The coating liquid was applied onto a silicon wafer by a flexographic printing method. After that, this coating liquid was dried at 90° C. for 5 minutes. After irradiating this coating liquid with ultraviolet rays (wavelength: 365 nm) at 3000 mJ/cm ² , this coating liquid was heated at 230° C. for 30 minutes to prepare a base material (silicon wafer) with a transparent film. SE-2000 was used to evaluate the refractive index and film thickness of the base material (silicon wafer) with a transparent film.

[Comparative Example 2]
A coating liquid was prepared in the same manner as in Example 1, except that the adamantane derivative was not mixed in the addition step.

[Comparative Example 3]
By replacing the solvent in 500 g of the methanol dispersion of titanium oxide of Example 4 with PGMEA using a rotary evaporator, 500 g of a PGMEA dispersion of titanium oxide having a solid content concentration of 20% by weight was obtained. This dispersion had a high viscosity and was cloudy.

Claims (9)

A film-forming coating liquid containing at least one of a titanium-containing oxide and a precursor thereof, an adamantane derivative, and an organic binder having an alkoxy group and a (meth)acrylate group . The titanium-containing oxide is contained in a solid content of 50 to 75% by weight,
10 to 35% by weight of the adamantane derivative is contained in the solid content,
2. The coating liquid according to claim 1, wherein the organic binder is contained in a solid content of 10 to 25% by weight. 2. The coating liquid according to claim 1, wherein at least part of said organic binder forms an oligomer. 2. The coating liquid according to claim 1, wherein the adamantane derivative has two or more (meth)acrylate groups in the molecule . 5. The coating liquid according to claim 4 , wherein the adamantane derivative does not have a substituent other than a (meth)acrylate group . 5. The coating liquid according to claim 4 , wherein the adamantane derivative has a molecular weight of 350 or less. a preparation step of preparing a dispersion comprising at least one of a titanium-containing oxide and a precursor thereof;
A mixing step of mixing the dispersion and an organic binder having an alkoxy group and a (meth)acrylate group to prepare a mixture;
and an addition step of adding an adamantane derivative to the mixture. In the mixing step, 10 to 40 parts by mass of the organic binder is mixed with 100 parts by mass of the titanium-containing oxide,
8. The method for producing a coating liquid according to claim 7 , wherein 15 to 80 parts by mass of the adamantane derivative is added to 100 parts by mass of the titanium-containing oxide in the adding step. A method for producing a film-coated substrate, comprising applying the coating liquid according to claim 1 onto a substrate to form a film.